perioperative care

INFORMED CONSENT

Colorectal surgical practice encompasses invasive surgi-cal interventions that range from outpatient endoscopicand digital examination to proposing pelvic clearance andsacrectomy for a recurrent rectal cancer. The purpose of acolorectal procedure is to restore an individual to health:a state of complete physical, mental and social well-being,not merely the absence of disease or infirmity. By the verynature of the conditions dealt with and the surgical pro-cedures employed, a proportion of patients admitted to acolorectal service will become ill, develop life-long disabil-ity and, in some cases, die from the surgical intervention.Many patients therefore correctly fear that consenting toa colorectal procedure could result in mutilation, disrup-tion of body image, destruction of sexuality and an inabil-ity to function in society. Perioperative care in colorectalpractice has to address all of these mental, physical andsocial concerns when preparing the individual patient andhis or her family for the planned procedure.

The key element in proceeding with an invasive col-orectal intervention is to obtain from the patient informedconsent. This is now widely recognised as more than get-ting a patient to sign a written consent form. The AmericanMedical Association has defined it as a process of commu-nication between a patient and physician that results in thepatient’s authorisation or agreement to undergo a specificmedical intervention. The British Medical Association(BMA) has issued the following principles that not only rep-resent good practice but go beyond the legal minimum forUK practice:

● Patient consent must be voluntary, free from pressure andarise from a competence to decide.

● Patient consent is required on every occasion the doctorwishes to initiate an examination or treatment or anyother intervention, except in emergencies or where thelaw prescribes otherwise. Consent can be verbal, writtenor implied by acquiescence by a person who understandswhat will be undertaken. Acquiescence when a patient

does not know what the intervention entails or that thereis an option of refusing is not ‘consent’.

● The amount of information doctors provide to eachpatient will vary according to factors such as the natureof the condition, the complexity of the treatment, the risksassociated with the treatment or procedure, and thepatient’s own wishes. The General Medical Councilrequires doctors to take appropriate steps to find out whatpatients want to know and ought to know about theircondition and its treatment.

● The doctor who recommends that the patient shouldundergo the intervention should have responsibility forproviding an explanation to the patient and obtaining hisor her consent. In a hospital setting this will normally bethe senior clinician. In exceptional circumstances the taskof reaffirming this consent may be delegated to a doctorwho is suitably trained and qualified, is sufficiently famil-iar with the procedure and possesses the appropriatecommunication skills.

● Generally, there is no legal requirement to obtain writtenconsent. The consent form simply documents that somediscussion about the procedure or investigation has takenplace. The quality and clarity of the information given isthe paramount consideration.

● Consent forms are evidence of a process; they are not theprocess itself. Any discussion, however, should be recordedin the patient’s medical notes.

● Competent patients are entitled to refuse consent totreatment even when doing so may result in permanentphysical injury or death.

● Legally, in England, Wales and Northern Ireland, no per-son can give consent to medical treatment on behalf ofanother adult. Doctors may treat a patient who lackscapacity, without consent, providing it is necessary andin the patient’s best interests. In Scotland, in some casesa proxy decision maker may be involved.

● Where a minor lacks capacity, a person or local author-ity with parental responsibility can give consent on behalfof the patient. Competent minors can give consent toexamination or treatment, but it does not necessarily

3PERIOPERATIVE CARE

Informed consent 69

Patient information 70

Risk 70

Measuring risk 70

Communicating risk: disclosure of

risk 80

Risk management 81

Mechanical bowel

preparation 81

Colorectal surgery and surgical site

infections 89

Thromboembolism prophylaxis 99

Transfusion and bleeding 105

Colorectal patients and high-

dependency care: evolution

of the surgical high-dependency

unit 105

Anaesthesia for colorectal

surgery 107

Colorectal surgery and

nutrition 115

Enhanced recovery after colorectal

surgery 123

References 126

Chapter 3 Perioperative Care70

follow that they have the same right to refuse treatment.The courts have made clear that, in England, Wales andNorthern Ireland, parents and courts do not lose theirright to give consent on behalf of a competent young per-son under the age of 18 even if the patient has refused thetreatment. It is possible that the Human Rights Act willchange the outcome of such cases in the future. InScotland, it is unlikely that a competent young person’srefusal can be overridden.

The principles of informed consent described by theAmerican Medical Association are similar (see http://www.ama-assn.org/ama/pub/category/4608.html) and includethe patient and surgeon discussing the following:

● The patient’s diagnosis, if known.● The nature and purpose of a proposed treatment or pro-

cedure.● The risks and benefits of a proposed treatment or proce-

dure.● Alternatives (regardless of their cost or the extent to

which the treatment options are covered by health insur-ance).

● The risks and benefits of the alternative treatment or pro-cedure.

● The risks and benefits of not receiving or undergoing atreatment or procedure.

PATIENT INFORMATIONProcedure-specific information that is relevant, understoodand retained by the patient is a key element in informedconsent. Over a timely period the patient and family shouldbe allowed to develop an informed view of benefits and haz-ards of the proposed procedure so that they take owner-ship of the decision to proceed or not to proceed with theplanned surgery. In practice, the proposed procedure, alongwith alternative courses of action and possible complica-tions, requires discussion between the patient and the sur-geon. It is useful for the patient to be accompanied by afriend or family member when these discussions takeplace. As well as the surgeon, the specialist colorectalnurse also provides an important source of information.Torkington et al (2003) examined the sources of informa-tion patients and their families used to make a decision asto whether or not to undergo an ileoanal pouch procedure.Preoperatively, 59 of 65 (91%) patients felt that thecolorectal nurse specialist and/or the consultant surgeonhad been the most influential source of information in thedecision to have a pouch procedure.

Videotaped or DVD information enhances significantlypatient knowledge about a procedure when compared toverbal information alone (Rossi et al, 2004). However,within colorectal practice, both DVDs and leaflets havebeen shown to increase a patient’s knowledge with respectto cancer surveillance in ulcerative colitis with meanpercentage improvements in scores of 71% [95% confi-dence interval (CI) 40.2–100] and 49% (95% CI 32.1–66),respectively (Eaden et al, 2002). As to the content ofpatient information leaflets, a comparison has been madefor patients undergoing gynaecological laparoscopy inwhich patients were randomised to receive one of two infor-mation leaflets. The old leaflet consisted of information

about the procedure (including a diagram of the pelvicarea), anaesthesia, preparation and normal after-effects,organised as one section. The new leaflet covered exactlythe same content, with two differences, it omitted the dia-gram and included two brief paragraphs headed ‘What arethe possible risks or complications?’ (Garrud et al, 2001).Whereas knowledge and patient satisfaction was higheramongst patients receiving the detailed complication infor-mation, the anxiety score was the same for both sets ofpatients. In clinical practice it is helpful to outline the out-comes and risks of a proposed procedure in correspondenceto both the referring clinician and the patient if theyrequest this. Such correspondence should include alloptions including the option of doing nothing.

The internet is a new and powerful source of patientinformation (Table 3.1). Gilliam et al (2003) studiedpatients undergoing follow up for Barrett’s oesophagus orcolonic polyps. Patients received a postal questionnaireseeking details of internet access and other sources of dis-ease specific information. The majority of patients (88%,n = 141) wanted more information on their condition.Interestingly, although 45% (73) had home internet access,and a further 32% (52) had access to the web from othersources, only 8% (12) had used the internet as a source ofinformation; however the majority (57% of patients) saidthey would access a recommended website. Al-Bahrani andPlusa (2004) have investigated the quality of internet sitesavailable for colorectal cancer patients. In their analysis,Google identified 55 700 sites for the search term ‘colo-rectal cancer’ and 214 000 for ‘bowel cancer’. Hotbotproduced 27 700 and 190 000, respectively. Of 400 sitesstudied in detail, 118 (30%) provided information, 70(18%) were lists of links, 27 (7%) were adverts, 22 (6%)promoted medical centres, 51 (13%) were dead links and15 (4%) were message boards. Of the 118 that providedinformation, 73 (62%) advised on treatment and 73 (62%)were designed for patients. The sources of information wereclear in 55 (47%) and the date when this information wasreported was given in only 63 (53%). Sites were classifiedas excellent 18 (15.3%), very good 19 (16.1%), good 28(23.7%), fair 8 (6.8%) and poor 45 (38.1%). The authors(Al-Bahrani and Plusa, 2004) concluded that cliniciansshould guide patients as to the quality of internet sites toavoid confusion and misinformation.

RISK

Risk: an unwanted event that might or might not occur.

MEASURING RISKUnwanted outcomes in colorectal surgery include postop-erative death, formation of a stoma, prolonged postopera-tive illness, loss of pelvic autonomic function and recurrenceof disease. Of these events, the risk of postoperative deathand illness has been addressed by the development of pre-operative scoring systems. Not only are these risk-assess-ment tools intended to inform individual patients of the riskthey face from a particular procedure, risk-adjusted out-comes are also intended to allow comparison between insti-tutional outcomes and individual surgeon outcomes. Jones

Risk 71

and de Cossart (1999) using a Medline literature searchidentified a wide range of preoperative and physiologicalscores of severity of illness.

ASA gradeThe grading system produced by the American Society ofAnesthetists (ASA) (Table 3.2) uses history and examina-tion to give a subjective evaluation of a patient’s clinicalstate before conducting an anaesthetic procedure. If theprocedure is conducted as an emergency, ‘E’ is added to thegrade to signify a worse prognosis for each category (Jonesand de Cossart, 1999).

In a prospective study of 3250 elective surgical patients,Klotz et al (1996) confirmed that high ASA grade was asso-

ciated with subsequent postoperative morbidity. Similarly,in a population of 6301 vascular and general surgerypatients, increasing ASA classification was strongly asso-ciated with postoperative death and the risk of postopera-tive complications (Wolters et al, 1996). When estimatingthe increased risk odds ratio for single variables, the risk ofcomplication was influenced mainly by ASA class IV (riskodds ratio = 4.2) and ASA class III (risk odds ratio = 2.2).

The subjective nature of the ASA grade and possibleinconsistency in its use has attracted some criticism.Haynes and Lawler (1995) sent a postal questionnaire to113 anaesthetists, of varying degrees of experience, work-ing in the Northern Region of England. Each anaesthetistwas asked to give an ASA grade to ten hypothetical

TABLE 3.2 AMERICAN SOCIETY OF ANESTHETISTS’ (ASA) GRADINGSYSTEM

ASA grade DescriptionI Normal healthy individualII Mild systemic disease that does not limit activityIII Severe systemic disease that limits activity but is not incapacitatingIV Incapacitating systemic disease which is constantly life threateningV Moribund, not expected to survive 24 hours with or without surgery

TABLE 3.1 INTERNET SOURCES OF PATIENT INFORMATION IN COLORECTAL SURGERY

American Society of Colon and RectalSurgeons: http://www.fascrs.orgAnal abscess/fistulaAnal cancerAnal fissureAnal wartsBowel incontinenceColonoscopyVirtual colonoscopyColorectal cancerColorectal cancer surgeryConstipationCrohn’s diseaseDiverticular diseaseHaemorrhoidsIrritable bowel syndromeOstomyPilonidal diseasePolyps of the colon and rectumPruritus aniRectal prolapseRectoceleUlcerative colitis

Association of Coloproctology of Great Britainand Ireland: http://www.acpgbi.org.ukACE procedureAbdominperineal excision of rectumAnal abscess/fistulaAnal fissuresAnorectal testsAnal wartsAnterior resection of the rectum

Crohn’s diseaseGTN (0.2%) ointmentHaemorrhoidsLateral anal sphincterotomyLeft hemicolectomyPolypsPruritus aniRectal cancerRight hemicolectomyTests for bowel problemsUlcerative colitis

Other useful websitesColorectal cancerhttp://www.patient.co.ukhttp://www.cancerresearchuk.org/http://www.nice.org.ukhttp://www.cancer.orghttp://www.gastro.orghttp://www.ccalliance.orghttp://www.hereditarycc.orghttp://www.nci.nih.govhttp://www.naric.com

Stomashttp://www.uoa.orghttp://www.the-ia.org.uk

Inflammatory bowel diseasehttp://www.nacc.org.ukhttp://www.mayoclinic.org/crohnshttp://www.ileostomypouch.demon.co.ukhttp://www.j-pouch.org

ACE, Antegrade continent enema; GTN, glyceryl trinitrate.

patients. In no case was there complete agreement on ASAgrade and in only one case were responses restricted to twoof the five possible grades. Despite these concerns, the ASAgrade is a bedside tool that persistently correlates with therisk of an adverse outcome in patient populations aftersurgical intervention.

Surgical risk scaleIn this system, each surgical procedure (Sutton et al, 2002)is allocated a score based on confidential enquiry into post-operative death (CEPOD) scheduling, BUPA (private healthinsurance scheme—the largest in the UK) operative sever-ity and ASA grade (Table 3.3). The scoring system was devel-oped using 3144 procedures associated with 134 deaths andvalidated using 2024 procedures associated with 62 deaths.

Univariate logistic analysis of the surgical risk scale (SRS)score revealed it to be significantly predictive of death andshowed that it did not over predict death in low-risk proce-dures. Brooks et al (2005) compared the SRS, Physiologicaland Operative Severity Score for the enUmeration ofMortality and morbidity (POSSUM) and Portsmouth POS-SUM (P-POSSUM) scores in 949 consecutive patients under-going inpatient surgical procedures in a district generalhospital under the care of a single surgeon. The observed30-day mortality rate was 8.4%. Mean mortality rates pre-dicted using SRS, POSSUM and P-POSSUM scores were5.9%, 12.6% and 7.3%, respectively. No significant differ-ence was observed in the area under the receiver-operatingcharacteristic (ROC) curves for the three methods. Specificrisk models can be used to accurately predict mortality, asfor instance one specifically designed for elderly patients withcolorectal cancer, where risk benefit of surgical interventionis particularly important in deciding whether an operationis advisable (Heriot et al, 2006).

Cardiopulmonary riskThe Goldman Cardiac Risk Index was specifically designedto predict the risk of cardiac complications following non-cardiac surgery. Nine factors are scored, giving a total pos-sible score of 0–53, factors included age, myocardialinfarction in the previous 6 months, S3 gallup or jugularvenous congestion, non-sinus rhythm and more than fivepremature ventricular contractions per minute (Jones andde Cossart, 1999). Prause et al (1997) studied 16 227 sur-gical patients in whom ASA grade and Goldman CardiacRisk Index were determined preoperatively. Both indices cor-related significantly with perioperative mortality, the ASAgrade showing a closer correlation. A regression tree analy-sis divided the combination groups into five subgroups; themortality was lowest (0.4%) in ASA grade ≤ 2 and GoldmanCardiac Risk Index group I (score 0–5 points) and increasedup to 7.3% in ASA grade = 4 and Goldman Cardiac RiskIndex group ≥ 3 (score > 13 points). Thus, combining bothscores can increase the perioperative prediction of postop-erative mortality (Prause et al, 1997) (Figure 3.1).

Gilbert et al (2000) compared four existing methodsfor predicting cardiac risk in 2035 patients: ASA,Goldman Cardiac Risk Index, modified Detsky Index andthe Canadian Cardiovascular Society Index. Cardiaccomplications (myocardial infarction, unstable angina,acute pulmonary oedema or death) were seen in 6.4% ofthe patient population. The area under the ROC curvewas 0.625 (95% CI 0.575–0.676) for the ASA grade,0.642 (95% CI 0.588–0.695) for the Goldman Index,0.601 (95% CI 0.544–0.657) for the modified Detskyindex and 0.654 (95% CI 0.601–0.708) for the CanadianCardiovascular Society Index. These values were not sig-nificantly different and Gilbert et al (2000) concludedthat existing indices for prediction of cardiac complica-tions perform better than chance, but that no index issignificantly superior to the others.

The prediction of pulmonary complications after non-cardiac surgery is less well explored. McAlister et al (2005)determined the incidence of postoperative pulmonary com-plications in 1055 consecutive patients attending thepreadmission clinic of a university hospital (mean age 55years, 50% men, 15% with history of obstructive airwaysdisease). Overall, 2.7% suffered a significant pulmonarycomplication within 7 days of surgery: 13 patients devel-oped respiratory failure requiring ventilatory support, ninepneumonia, five atelectasis requiring bronchoscopic inter-vention, and one pneumothorax requiring intervention.Multivariate analyses revealed that four preoperative fac-tors were independently associated with increased risk ofpulmonary complications: age [odds ratio (OR) 5.9 for age≥ 65 years, P < 0.001], positive cough test (OR 3.8, P =0.01), perioperative nasogastric tube (OR 7.7, P < 0.001)and duration of anaesthesia (OR 3.3 for operations lastingat least 2.5 hours, P = 0.008).

Colorectal scoring systemsACPGBI colorectal cancer modelThis model (Tekkis et al, 2003b) was constructed withdata from 73 hospitals, forwarded on a voluntary basisto the Association of Coloproctology of Great Britain andIreland (ACPGBI) and encompassing 8077 new cases of


TABLE 3.3 SURGICAL RISK SCALE(AFTER SUTTON ET AL, 2002)

Factor ScoreCEPODElective 1Scheduled 2Urgent 3Emergency 4

BUPAMinor 1Intermediate 2Major 3Major plus 4Complex major 5

ASAI 1II 2III 3IV 4V 5

ASA, American Society of Anesthetists; BUPA, British United

Provident Association (British private health insurance scheme);

CEPOD, confidential enquiry into postoperative death.

colorectal cancer. Factors initially considered includedage, sex, ASA grade, cancer site, procedure, urgency,Dukes stage, cancer excision and case volume. In 30% ofthe 7374 patients used for the analysis, 2216 did nothave recorded ASA grades. The overall postoperative inhospital mortality was 7.5% and the independent predic-tors of death were age, ASA grade, Dukes stage, urgencyof the operation and cancer excision (Table 3.4). A scorecan be calculated for each factor and converted into anindividual risk.

The authors of the model (Tekkis et al, 2003a) proposethat it can be used to give individual patients and theircarers an estimated probability of survival from surgery.However, two of the five variables (resection/no resectionand Dukes stage) are available only after patients havesubjected themselves to the irrevocable step of surgicalresection. As such, the model has limited application tocommunicating preoperative risk. In addition, the ACPGBIcolorectal cancer (CRC) model might be accurate for elec-tive cases but appears to significantly underestimate pre-dicted mortality in the emergency setting, both actual andpredicted by P-POSSUM. This could be due to a failure toincorporate adequate weighting for faecal peritonitis andthe associated systemic insult into the ACPGBI model(Metcalfe et al, 2005)

Cleveland clinic ileal pouch failure modelWhen counselling patients as to the risks and benefits ofileal pouch surgery it would be useful to identify thosepatients that might be at risk of ileoanal pouch failure—defined as excision of the ileoanal pouch (Fazio et al, 2003).The Cleveland Clinic model considered risk factors in 1965patients including the presence of prior anal pathology(perianal abscesses, fistula-in-ano, fissure-in-ano, or sig-nificant haemorrhoids/skin tags), extraintestinal manifes-tations of inflammatory bowel disease, patient comorbidity(cardiac, respiratory, renal impairment, diabetes or morbid

obesity), preoperative diagnosis, anal sphincter manome-try (mean resting pressure and squeeze pressure measuredin mmHg) and previous abdominal operations, Other fac-tors taken into consideration included details of surgicalprocedures, postoperative pathologic diagnoses along withthe early (within 30 days of surgery) and late complica-tions. Pelvic sepsis was defined as the presence of para-pouch abscesses and excluded anastomotic leak andpouch-related fistulae, which were recorded as separatecomplications. Chronic pouchitis was defined as four ormore episodes of pouchitis per year or the need for chronicantibiotic, immunosuppressive therapy to control symp-toms, in addition to endoscopic evidence of pouch inflam-mation (Fazio et al, 2003). The median patient follow-upwas 4.1 years (range 0–19 years). Five-year ileal pouch sur-vival was 95.6% (95% CI, 94.4–96.7). The following riskfactors were found to be independent predictors of pouchsurvival: patient diagnosis, prior anal pathology, abnormalanal manometry, patient comorbidity, pouch-perineal orpouch-vaginal fistulae, pelvic sepsis, anastomotic strictureand separation.

Although an interesting approach to counselling andselecting patients for ileoanal pouch surgery, the ileal pouchfailure model has two significant problems (Marcello,2004). The first is that of all the numerous factors consid-ered in the model, only four can be determined before sur-gery: prior anal pathology (perianal abscess, fistula-in-ano,anal fissure, haemorrhoids), preoperative diagnosis (Crohn’sdisease versus ulcerative colitis and indeterminate colitis),patient comorbidity (cardiac, respiratory, renal, diabetes,morbid obesity) and a weak anal sphincter by manometry.The other risk factors that arise from pouch surgery andassociated complications are not known when the patientis trying to get a view of the likelihood of success or failure,i.e. before committing to the procedure. The second problemis how applicable is the model to other colorectal centresoffering pouch surgery (Marcello, 2004).

Risk 73

Figure 3.1 Classification andregression tree analysis showingincreased predicting power of thetwo scores combined. Figures areper cent mortality. From Prause et al(1997).

ASA ≤ 3

CRI ≤ IIASA ≤ 2

CRI ≤ I

YES

YES

3.19% 4.40%

YES

NO

NO

NOYES

NO

0.40% 1.36% 7.29%

Physiological scoring of illness severityPOSSUM developmentThe Physiological and Operative Severity Score for theenUmeration of Mortality and morbidity was developed byGraham Copeland (Copeland et al, 1991) to provide risk-adjusted mortality rates in general surgery. From a start-ing point of measuring 62 factors, the authors were ableto use multivariate analysis to identify the most importantpredictors: 12 physiological and 6 operative factors (Table3.5). Thus, although other factors might be significant insurgical outcome, their contribution did not add to thepower of the selected 18 factors. To approximate to theirrelative predictive value, each factor was subdivided intotwo to four levels and given a weighted score of between 1and 8. POSSUM outperformed APACHE II scoring in theprediction of postoperative death and morbidity amongst177 patients admitted to a surgical high-dependency unit(Jones et al, 1992).

However, the general application of POSSUM to thetotality of a UK general surgical population has been ques-tioned by Bann and Sarin (2001), who studied 521 oper-

ations performed on 501 patients. In total, 162 of thesewere classified as emergency and 342 as elective; theremaining 17 operations were performed on transferredpatients. A complete POSSUM score was only obtained in155 patients (29.8). Bann and Sarin (2001) concludedthat this evaluation cast serious doubt on the suitability ofPOSSUM for use in audit of general surgeons. In particu-lar, exclusion of day cases and children from POSSUM, 48%of the workload, along with a blanket approach to preop-erative investigation for inpatient treatment that was notin keeping with hospital guidelines, were significant weak-nesses in the use of POSSUM.

The major disadvantage of the original POSSUM pre-diction equation is a tendency to overpredict patient deathin low-risk general surgery. Whiteley et al (1996) foundthat the bulk of the overprediction occurred in the groupat lowest risk (predicted mortality 10% or less), in whichdeath was overpredicted by a factor of six. The authorsfound that the original POSSUM predictor equation formortality returns a minimum predicted mortality of1.08%, much greater than that expected for a fit patient


TABLE 3.4 THE COLORECTAL CANCER MODEL OF THE ASSOCIATIONOF COLOPROCTOLOGY OF GREAT BRITAIN AND IRELAND (ACPGBI)AND CONVERSION CHART OF ACPGBI SCORE TO PREDICTED 30-DAYOPERATIVE MORTALITY FOR PATIENTS UNDERGOING SURGERY FORCOLORECTAL CANCER

ACPGBI colorectal Predicted Risk factor Score cancer score mortality (%)

Age (years)< 65 0 0 0.865–74 0.7 0.1–0.4 0.9–1.175–84 1.1 0.5–0.8 1.3–1.784–95 1.3 0.9–1.2 1.9–2.5> 95 2.6 1.3–1.6 2.8–3.7

Cancer resectedASA I 0 1.7–2.0 4.1–5.4ASA II 0.8 2.1–2.4 6.0–7.9ASA III 1.6 2.5–2.8 8.6–11.3ASA IV–V 2.5 2.9–3.2 12.3–16.0

Cancer not resectedASA I 1.7 3.3–3.6 17.4–22.1ASA II 1.8 3.7–4.0 23.9–29.8ASA III 2.1 4.1–4.4 31.9–38.7ASA IV–V 2.4 4.5–4.8 41.1–48.5

Cancer stagingDukes’ A 0 4.9–5.2 51.0–58.4Dukes’ B 0 5.3–5.6 60.8–67.7Dukes’ C 0.2 5.7–6.0 69.9–75.8Dukes’ D or any metastases 0.6 6.1–6.4 77.6–82.4

Operative urgencyElective 0 6.5–6.8 83.8–87.4Urgent 0.8Emergency 1.1

After Tekkis et al (2003b).

having minor surgery. Whiteley et al (1996) used logisticregression on data from a set of 1485 surgical episodesto generate a local predictor equation for mortality. Thisgave a predictor equation that fitted well with theobserved mortality rate and gave a minimum predictedrisk of mortality of 0.20%. Even this risk of death inminor surgery (1 : 500) can be seen as an overestimate(Table 3.6).

Prytherch et al (1998) compared the performance ofthe original POSSUM equation with the performance of theP-POSSUM in 10 000 general surgical cases managedbetween 1993 and 1995. The 10 000 patients werearranged in chronological order and the first 2500 wereused as a training set to produce the modified P-POSSUMpredictor equation. This was then applied prospectively tothe remaining 7500 patients, who were arranged chrono-logically in five groups of 1500. The original POSSUM mor-

tality equation showed a significant lack of fit between thepredicted mortality and the observed mortality. By contrast,the P-POSSUM equation gave much better agreementbetween expected and observed mortality and has beenproposed as the standard methodology of calculatingexpected outcomes against which observed outcomes canbe measured (Table 3.7).

The comparative utility of the two POSSUM equationsin predicting death after gastrointestinal surgery wasexamined using 505 patients, 65% of whom had colorec-tal procedures, 27.5% upper gastrointestinal surgery and7.5% small bowel surgery (Tekkis et al, 2000). In this com-parison, the observed overall operative mortality rate was11.1% (elective was 3.9% and emergency was 25.1%).The Portsmouth predictor equation for mortality equationpredicted a mortality rate of 11.3% (P = 0.51). However,the original POSSUM equation was found to overpredictdeath by a factor of two: 21.5% (P < 0.001) (Tekkis et al,2000).

Physiological scoring and colorectal surgeryIn a Saudi Arabian population of rectal cancer patients,POSSUM failed to predict outcomes accurately in patientsundergoing surgery, P-POSSUM also overpredicted mor-tality but to a lesser extent (Isbister and Al Sanea, 2002).The overall POSSUM predicted (using median scores)morbidity and mortality rates were 35.4% and 6.7%. TheP-POSSUM predicted (using mean scores) mortalityrate was 3.5%. Observed morbidity and mortality rateswere 54.5% and 1.4%.

Tekkis et al (2003a) examined the predictive value ofboth POSSUM and P-POSSUM within a population under-going colorectal procedures using the outcomes of 1017patients (79% elective and 21% emergency). The overalloperative mortality rate was 7.5% (POSSUM-estimatedmortality rate 8.2%; P-POSSUM-estimated mortality rate7.1%). Both scoring systems overpredicted mortality inyoung patients and underpredicted mortality in the elderly(P < 0.001). In addition, death was underpredicted by bothequations for emergency cases (Table 3.8).

By contrast, Poon et al (2005) found a good fit betweenP-POSSUM-predicted mortality and observed mortality inpatients presenting with colorectal malignant obstruction.A total of 160 patients were included in the study, of whom18 died postoperatively. The observed operative mortalitywas therefore 11.3%, compared with the P-POSSUM pre-dicted overall mortality of 15%. The observed and predictedmortality was found to have no significant lack of fit (chi-squared = 5.98; degrees of freedom = 3; P = 0.11). POS-SUM is also an accurate predictor of 5-year survival incolorectal cancer (Brosens et al, 2006).

Laparoscopic assisted colectomy presents furtherchallenges for the predictive value of both POSSUM andP-POSSUM. In a series of 250 consecutive laparoscopicassisted colectomies, the observed morbidity rate (6.8%)was significantly lower than the predicted rates calculatedwith an operative score of 4 or 2 (12.4%, P < 0.001; 9.6%,P = 0.001) but was fully corrected with an operative scoreof 1 (7.0%, P = 0.325) (Senagore et al, 2003). In addi-tion, the observed mortality rate (0.8%) was significantlylower than the expected mortality rates calculated using

Risk 75

TABLE 3.5 PREOPERATIVE ANDOPERATIVE FACTORS SCORED TO CALCULATE POSSUM

Physiological OperativeAge Operative complexityCardiac history Multiple proceduresElectrocardiogram Blood loss

report Peritoneal contaminationRespiratory history Extent of malignant spreadBlood pressure Elective versus emergency Pulse rate surgeryGlasgow Coma ScaleHaemoglobinWhite cell countUreaSodiumPotassium

POSSUM, Physiological and Operative Severity Score for the

enUmeration of Mortality and morbidity; P-POSSUM,

Portsmouth Physiological and Operative Severity Score for the

enUmeration of Mortality and morbidity.

TABLE 3.6 ORIGINAL POSSUM AND P-POSSUM PREDICTOR EQUATIONS FOR MORTALITY

EquationPOSSUM ln R/1 − R = −7.04 + (0.13 ×

physiological score) + (0.16 ×operative score)

P-POSSUM Ln R/1 − R = −9.065 + (0.1692 ×physiological score) + (0.1550 ×operative score)

From Whiteley et al (1996).

POSSUM, Physiological and Operative Severity Score for the

enUmeration of Mortality and morbidity; P-POSSUM,

Portsmouth Physiological and Operative Severity Score for the

enUmeration of Mortality and morbidity.

either the original POSSUM equation (9.6%, P = 0.001)or the P-POSSUM equation (3.5%, P = 0.001).

Subsequently, an age-adjusted POSSUM model and adedicated (colorectal) CR-POSSUM model (Tekkis et al,2004) have been developed using a population of 6883patients undergoing colorectal surgery in 15 hospitals inthe UK, in a 60 : 40% split-sample validation technique.The subcategories for each factor included in the final CR-POSSUM model were weighted according to odds ratiosderived from multivariate logistic regression analysis. POS-SUM variables relating to the structure and process of care

were excluded from the multifactorial models; includingoperative blood loss and number of procedures (Table 3.9).

Comparison was made between the performance of P-POSSUM, age-adjusted POSSUM and CR-POSSUM. In thiscomparison, the P-POSSUM model overpredicted mortal-ity in the low-risk group of patients (0–9.9% mortality rategroup) and underpredicted outcome in the higher-riskgroup (mortality rate of 20–29.9%), a difference that wasstatistically significant. The age-adjusted and CR-POSSUMmodels fitted the data well, with no significant discrepan-cies between observed and predicted outcomes, as


TABLE 3.7 THE ORIGINAL POSSUM EQUATION APPLIED TO 10 000CASES AND THE P-POSSUM EQUATION APPLIED TO LAST 1500PATIENTS

Predicted No. of Predicted Observed mortality operations deaths deaths

Original POSSUM equation applied to 10 000 cases0–5 7034 159 225–15 1879 160 6815–50 866 227 12050–100 221 151 770–100 10000 697 287

P-POSSUM equation applied to last 1500 patients0–5 1331 13 135–15 121 10 1315–50 37 10 950–100 11 8 70–100 1500 41 42

From Prytherch et al (1998).

POSSUM, Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity;

P-POSSUM, Portsmouth Physiological and Operative Severity Score for the enUmeration of Mortality

and morbidity.

TABLE 3.8 POSSUM AND P-POSSUM UNDERPREDICTION OF DEATHIN EMERGENCY COLORECTAL SURGERY AND ELDERLY PATIENTSSUBJECTED TO COLORECTAL SURGERY

Observed mortality P-POSSUM POSSUM n (range) mortality mortality

OperationElective 804 3.2 (2.1–4.7) 3.8 4.6Emergency 213 23.4 (18.0–30.0) 19.5 16.7

Age< 50 192 0.5 (0.1–2.9) 2.6 3.350–59 149 2.7 (0.7–6.7) 3.6 6.160–69 228 5.3 (2.7–9.0) 6.2 7.570–79 290 8.6 (5.7–12.5) 9.7 11.8> 80 158 22.0 (16.0–29.4) 12.3 12.4Total 1017 7.5 (5.9–9.3) 7.1 8.2

From Tekkis et al (2003a).

POSSUM, Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity;

P-POSSUM, Portsmouth Physiological and Operative Severity Score for the enUmeration of Mortality

and morbidity.

evidenced by the calibration plot (Figure 3.2) (Tekkis et al,2004). Similar observations have now been reported whenPOSSUM, P-POSSUM and CR-POSSUM were compared(Ramkumar et al, 2006).

Al-Homoud et al (2004) compared the accuracy of twopredictive models based on ASA grade (the ACPGBIColorectal Cancer model and the Malignant BowelObstruction model) with the CR-POSSUM model based onphysiological and operative scoring. The test populationconsisted of the 16 006 patients with diseases of the colonand rectum who were included in the three multicentre

UK-based studies that were used to develop the three prog-nostic models (Al-Homoud et al, 2004). For each of thethree models, discrimination (as shown by the area underthe ROC curve), was similar in the ACPGBI CRC (77.5%)and MBO (80.1%) models but was higher in the CR-POSSUM model (89.8%). All three models fitted the datawell, with no significant discrepancies between theobserved and predicted mortality, as tested by theHosmer–Lemeshow c statistic (Table 3.10).

The authors concluded that all three predictive modelscan be used in everyday practice for preoperative counselling

Risk 77

TABLE 3.9 THE COLORECTAL POSSUM SCORING SYSTEM

Score

1 2 3 4 8Age group (years) ≤ 60 61–70 71–80 ≥ 81Cardiac failure None or mild Moderate SevereSystolic blood pressure (mmHg) 100–170 > 170 or 90–99 < 90Pulse (beats/min) 40–100 101–120 > 120 or < 40Urea (mmol/L) ≤ 10 10.1–15.0 > 15.0Haemoglobin (g/dL) 13–16 10–12.9 or 16.1–18 < 10 or > 18

Operative severity scoreOperative severity Minor Intermediate Major Complex majorPeritoneal soiling None or Local pus Free pus

serous fluid or faecesOperative urgency Elective Urgent EmergencyCancer staging No cancer or Dukes’ C Dukes’ D

Dukes’ A,B

From Tekkis et al (2004).

Colorectal POSSUM equation: ln[R/(1 − R)] = −9.167 + (0.338 × PS) + (0.308 × OSS), where PS is the total Physiological Score and OSS is the total

Operative Severity Score.

CR-POSSUM, Colorectal POSSUM; POSSUM, Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity.

Observed mortality

P-POSSUMAge-adjusted POSSUM

CR-POSSUM

Risk of mortality (%)

Op

erat

ive

mor

talit

y (%

)

50

40

30

20

10

00−4.9 5−9.9 10−19.9 20−29.9 30−100 0−100

Figure 3.2 Calibration of the three Physiological and Operative Severity Scores for the enUmeration of Mortality and morbidity(POSSUM) models according to the risk of mortality: Portsmouth (P)-POSSUM, age-adjusted POSSUM and colorectal (CR)-POSSUM. Each bar represents the mean observed or predicted in-hospital operative mortality rate; error bars indicate the 95%confidence interval for observed mortality. From Tekkis et al (2004).

of patients and their carers, as a part of the process ofinformed consent. In addition, they can be employed tocompare outcomes between multidisciplinary CRC teamsand therefore are a powerful tool not only for the purposesof consent, but also for audit, research, training andrevalidation (Al-Homoud et al, 2004).

Comparative auditBetween national health systemsComparison between national health-care systems can beexplored using risk-adjusted data as defined by P-POSSUM(Bennett-Guerrero et al, 2003). Using Mount Sinai Hospitalas the US centre and Queen Alexandra Hospital and StMary’s Hospital Portsmouth as the UK centres, two com-parative populations of surgical patients were identified.Among the 1056 patients treated in the US, POSSUM phys-iology scores ranged from 12 to 42 and the operative sever-ity scores from 6 to 37. For the 1539 patients treated in theUK, respective POSSUM scores ranged from 12 to 52 andfrom 9 to 40. The severity of the operations performed ineach country was similar between groups: the US cohorthad a mean (s.d.) (median, interquartile range) operativeseverity score of 16.7 (5.7) (17, 13–20) and the UK cohort16.5 (6.2) (16, 11–20) (P = 0756). Overall, the mean (s.d.)(median, interquartile range) postoperative length of stayin hospital was slightly lower for patients in the US cohort[10.3 (12.6) (8, 6–10) days] compared with that for theUK cohort [11.8 (11.6) (9, 5–14) days] (P < 07001)(Bennett-Guerrero et al, 2003). Within both the US andthe UK cohorts, an increase in risk estimated by P-POSSUMpredicted an increase in observed mortality rate (P <07001). However, for any given risk level (Figure 3.3), themortality rates were significantly higher in the UK cohortthan in the US cohort [odds ratio 4.50 (95% CI 2.81–7.19);Z = 6725; P < 07001) (Bennett-Guerrero et al, 2003).

Although these differences cannot be generalised to theentire US and UK health-care systems, these findingsshould stimulate further exploration into potential causes

and strategies to improve patient management (Bennett-Guerrero et al, 2003).

A similar exploration of the utility of POSSUM, P-POS-SUM and CR-POSSUM to health care in nine hospitals inCleveland, Ohio, was carried out by Senagore et al (2004).A total of 890 colon cancer resections were studied; resec-tions per institution ranged from 13 to 437. The observedmortality rate ranged from 0.8% to 15.4% among the


TABLE 3.10 COMPARISON OF MODEL PERFORMANCE BETWEENACPGBI CRC, MBO AND COLORECTAL-POSSUM SCORING SYSTEMS

Model performance (validation set)

Study Discriminationa Calibrationb O : E mortalityc (%)ACPGBI CRC 77.5% (1.6%) 5.98, P = 0.649 7.5 : 7.5MBO 80.1% (1.9%) 7.606, P = 0.473 14.3 : 13.5CR-POSSUM 89.8% (1.1%) 5.01, P = 0.756 5.7 : 5.7

From Al-Homoud et al (2004).aDiscrimination is measured by the area under the receiver–operator characteristic curve (standard error):

higher values represent better model discrimination.bCalibration is measured by the Hosmer–Lemeshow c statistic (8 degrees of freedom): smaller values

represent better mode calibration.cO : E = Observed to expected mortality in the validation set.

ACPGBI, Association of Coloproctology of Great Britain and Ireland; CRC, colorectal cancer; CR-POSSUM,

Colorectal POSSUM; MBO, malignant bowel obstruction; POSSUM, Physiological and Operative Severity

Score for the enUmeration of Mortality and morbidity.

UK cohortUS cohort

P-POSSUM-estimated risk of death (%)

Mod

el-b

ased

ris

k of

dea

th (

%)

90

80

70

60

50

40

30

20

10

100

0 10 20 30 40 50 60 70 80 90 100

Figure 3.3 Risk-adjusted mortality rates for US (n = 1056)and UK (n = 539) cohorts based on the multivariate logisticregression model. The relationship between the risk of deathpredicted by the Portsmouth Physiological and OperativeSeverity Score for the enUmeration of Mortality andmorbidity (P-POSSUM) and the risk-adjusted mortality ratesin each of these cohorts based on the multivariate logisticregression model is shown. From Bennett-Guerrero et al(2003).

institutions, with an overall operative mortality of 2.3%.The POSSUM, P-POSSUM and CR-POSSUM predicted mor-tality was 10.7%, 11.2% and 4.9%, respectively. The POS-SUM and P-POSSUM models overpredicted mortality in allinstitutions (P < 0.01), whereas the CR-POSSUM demon-strated an observed over expected hospital mortality ratioof > 1 in three institutions. It might be that a recalibrationprocess is required in order for POSSUM scoring to accu-rately reflect US mortality surgical outcomes (Senagoreet al, 2004).

Between institutionsIn the US, Veterans’ Affairs (VA) medical centres, with acentralised administration and data collection process, areuniquely able to compare the surgical outcomes of differ-ent institutions. This process is the National VA SurgicalQuality Improvement Program (NSQUIP). This auditencompassed a surgical database of 417 944 major surgi-cal procedures from 123 VA medical centres that recordedpresurgical risk factors, process of care during surgery andoutcomes 30 days after surgery (Khuri et al, 1998). Logisticregression analysis was used to develop the predictive mod-els for surgical death and complications. In this logisticregression model, surgical death and complications are thedependent variables; the presurgical risk factors (Table3.11) are the independent variables.

Using this model, comparisons of expected and observedmortality in each institution identified low and high out-lier hospitals for 30-day mortality rates for all surgicalprocedures are identified (Figure 3.4).

Hospitals with consistently low outlier status are com-mended and encouraged to share with the NSQIP (whichsubsequently disseminates this information to the rest ofthe medical centres) the processes and structures that thesehospitals consider to have contributed to their good per-formance. Various levels of concern are raised about high

outlier hospitals and suggestions are forwarded regardinginternal and external reviews to verify and improve out-comes of surgery at these hospitals (Khuri et al, 1998).Subsequent analysis has shown that the NSQUIP modelof risk adjustment can be applied to other non-federal UShospitals (Fink et al, 2002).

Risk 79

TABLE 3.11 ORDER OF ENTRY OF MOSTPREDICTIVE PREOPERATIVE RISKFACTORS IN MORTALITY MODELS FORNON-CARDIAC SURGERY

Risk factor Average rankSerum albumin 1ASA class 2Disseminated cancer 3.3Emergency operation 4.3Age 5BUN > 40 mg/dl 7DNR 7.3Operation complexity score 11SGOT > 40 IU/mL 11.3Weight loss > 10% in 6 months 11.5Functional status 12.3WBC > 11 000/mm3 14

From Khuri et al (1998).

ASA, American Society of Anesthetists; BUN, blood, urea,

nitrogen, DNR, do not resuscitate; SGOT, serum glutamic

oxaloacetic transaminase; WBC, white blood cells.

BEFORELow outlier surgical services rankedby observed 30-day mortality rate (%)

HospitalCode

HospitalCodeRank Rank

Low outlier surgical services ranked byrisk-adjusted O/E ratio for 30-day mortality

% O/E

AFTER

p

0.026

0.020

0.030

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0.0005

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0.0001

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0.77

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Misclassified byunadjustedmortality rate

A

BEFOREHigh outlier surgical services rankedby observed 30-day mortality rate (%)

HospitalCode % Rank

High outlier surgical services ranked byrisk-adjusted O/E ratios for 30-day mortality

AFTER

HospitalCode O/E Rankp

0.035

0.036

0.017

0.014

0.002

0.015

0.016

0.011

0.003

0.031

0.001

0.006

0.001

0.0007

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0.007B

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7.1

107

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1.23 111

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1.33

1.34

1.35

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1.37

1.40

1.46

1.46

1.48

1.50

1.68

2.31

Misclassified byunadjustedmortality rate

121

122

123

Figure 3.4 Low (panel A) and high (panel B) outlierhospitals in 30-day mortality rates for all surgical proceduresperformed during FY97. Within each panel, the hospitals’rankings by adjusted and unadjusted mortality rates arecompared. Hospitals appearing in both rankings areconnected with a line. In the columns showing the risk-adjusted mortality rates, the O/E ratios shown are those thatare significantly different from one at the 90% confidencelimits. In the columns showing the unadjusted mortalityrates, a probability value is calculated that refers to the testcomparing each hospital’s observed mortality rate to theobserved mortality rate of all hospitals combined (P < 0.05).From Khuri et al (1998).

Between surgeonsHuman nature is, however, less interested in institutionalperformance than in the question ‘Who is the surgeon whois least likely to kill me and most likely to fix me?’

This question fits with the moves in recent years toincrease openness and transparency in the delivery ofhealth care. In the UK, this has been accelerated by theBristol Royal Infirmary inquiry into paediatric surgicaldeaths (Bridgewater, 2005). This inquiry included 198 rec-ommendations, of which two stated that patients must beable to obtain information on the relative performance ofthe Trust and of consultant units within the Trust. This ledto an increasing belief that the interests of the public andpatients would be served by publication of individuals’ sur-gical performance in the form of postoperative mortality(Keogh et al, 2004).

In the US, outcomes attributable to individual cardiacsurgeons in New York were dragged into the public arenain December 1991. The New York department of healthwas sued by a newspaper, Newsday, using the state’sFreedom of Information Law. The lawsuit was lost andthe surgeon-specific mortality data was given to Newsday,and published in December 1991 (Chassin et al, 1996).Interestingly no movement of patients away from hospitalswith high mortality rates has occurred. Thus, in 1989,8.7% of all patients undergoing CABG were treated at hos-pitals whose risk-adjusted mortality rates were significantlyhigher than the State average, and 15.7% were treated athospitals with significantly lower rates. The comparable fig-ures in 1993 were 9.5% and 17.0%, respectively (Chassinet al, 1996).

Recently, the Freedom of Information Act has becomelaw in England and Wales. This gives individuals the rightto obtain data from public organisations. Under the Act, itis inevitable that individual surgeon data will come into thepublic domain. Some individual hospitals are respondingby putting results on the internet (Bridgewater, 2005). Ifit is to be useful to the public and fair to individual surgeons(Bridgewater, 2005), mortality data:

● should be easy to understand● needs to be based on robust data● must compare like with like, i.e. risk adjusted● should not engender a surgical culture of avoiding high-

risk patients.

Comparison of individual surgeon outcomes after colorec-tal resection using unadjusted data demonstrates widevariations: morbidity varying from 13.6% to 30.6% andmortality from 4.5% to 6.9%. However, risk-adjustedanalysis based on POSSUM scores demonstrated that thepredicted outcomes expected for each surgeon’s casemixwere very similar to those observed (Sagar et al, 1996).Tekkis et al (2000) similarly found that the mortality ratesamong the four surgeons varied from 7.6% to 14.7%. Theobserved-to-expected ratio of deaths for the original POS-SUM equation was only 0.45 to 0.56 but for P-POSSUMthe predictor equation for mortality was close to unity(0.905 to 1.067) for all four surgeons.

Keogh et al (2004) point out that although the surgeonplays an important role in surgical outcome, so do manyother important factors. These include which patients are

selected for surgery, which is affected by socioeconomic sta-tus of the local population, prevalence of comorbidities,threshold of referral from the general practitioner andthreshold of acceptance by the surgeon. In addition, thereis the influence of the entire health-care infrastructure—the anaesthetist, the intensive care physician, the surgical/high-dependency nurse, the junior surgical staff enmeshedwith local standards of anaesthesia, surgery and intensivecare; adequacy of facilities and staffing levels; attitudestowards training; interpersonal relationships between staff;and the geographical layout of the unit (for example, insome units the wards are so far from the theatre that sur-geons have no time to check-up on ward patients betweensurgery cases).

In the authors’ view this complex interaction cannot bereflected in surgeon-specific outcomes. We agree with theapproach taken in the VA medical centres outlined above,i.e. the National VA Surgical Quality ImprovementProgram (NSQUIP; Khuri et al, 1998). This approachovertly recognises that the performance of a surgeon can-not be separated from that of his or her institution, as qual-ity is highly dependent on institutional systems. Forhealth-care systems to develop these comparative audits,investment is required in valid data collection and pro-cessing that generates meaningful institutional out-comes, which can in turn be used for constructive serviceimprovement.

COMMUNICATING RISK: DISCLOSURE OF RISKThe right to free and informed consent is an internationalobligation placed on all health-care workers (Moumjid andCallu, 2003). The new medical conversation integrates riskcommunication into the doctor–patient consultation(Edwards, 2003). The information offered should be sim-ple, relevant, and responsive to the needs and values of theindividual patient. Difficult and complex risks will requirea series of consultations, at the end of which both surgeonand patient might have to share the same uncertainties asto the outcome of the proposed procedure (Edwards,2003).

The first barrier, for both professional and patient, is inunderstanding the arithmetic size of the proposed risk:moving from innumeracy to insight (Gigerenzer andEdwards, 2003). Three classes of numerical representationthat lead to confusion—single-event probabilities, condi-tional probabilities and relative risks—are discussed byGigerenzer and Edwards (2003). In their account theyconsider ways in which alternative representations mightpromote insight (Table 3.12).

In most colorectal surgical consultations, single-eventprobabilities are presented in the course of discussing a sur-gical intervention. Thus, for a patient being counselled forelective colorectal cancer resection (5% mortality), it wouldbe appropriate to inform the patient and his or her familythat, of every 20 patients admitted for resection, onepatient dies within 30 days of the procedure. However,presenting risk to a patient is not only about the numeri-cal data but also the context in which it is presented.For effective risk communication, the colorectal surgeonhas to display both competence and a caring approach


(Paling, 2003). Other important communication strategiesdescribed by Paling (2003) include:

● Avoiding the use of descriptive terms only (e.g. terms suchas ‘low risk’).

● Using standardised vocabulary (‘very common’, ‘com-mon’, ‘uncommon’, ‘rare’ and ‘very rare’).

● Using a consistent denominator (e.g. 40 out of 1000 and5 out of 1000, rather than 1 in 25 and 1 in 200). Manypatients can mistake which is the greater risk if differentdenominators are used.

● Using absolute numbers.● Using visual aids for probabilities.

RISK MANAGEMENT

MECHANICAL BOWEL PREPARATIONThe need for some method of bowel preparation wasproposed soon after the introduction of colonic resectionrather than colostomy for the management of large boweldisease (Reybar, 1844; Wilkie, 1938). In the past, clini-cians relied upon a period of starvation (allowing liquidsonly for 4–5 days), purgation (usually with magnesiumsalts), enemata and rectal washouts (Rogers, 1971, Miller,1975). During the 1970s and 1980s new techniques wereintroduced, largely to improve patient compliance andreduce the length of preoperative hospital stay (Huddyet al, 1990; Lee et al, 1996). In this section we present adetailed account of mechanical bowel preparation forpatients undergoing colonic resection and/or endoscopicinspection of the colon. This is because for many colorec-tal surgeons in the USA and the UK, colonic preparation

continues to be a cornerstone of modern elective colorec-tal surgery in preventing sepsis (Nichols et al, 2005).Others, however, take an entirely contrary view in whichmechanical bowel preparation before elective colonic sur-gery is viewed as injurious to the patient (Fearon et al,2005).

Distal preparationEnemata are essential if sigmoidoscopy is uninformativebecause of gross faecal residue. This is particularly relevantto pouch surveillance after restorative proctocolectomy aswell as for examination of the rectum after ileorectal anasto-mosis. Devlin et al (1979) compared dioctyl sodium sulpho-succinate (1% w/v) with sodium acid phosphate (10%) andwith soap enemata (5% w/v). All three preparations wereequally successful for rigid sigmoidoscopy. Although thedioctyl and phosphate enemata were more expensive thanthe soap enemata, the added cost of the proprietary prepa-rations was justified by reduced nursing time. An outpatientflexible sigmoidoscopy is often desirable in a patient with asuspected carcinoma in the sigmoid which cannot be visu-alised or biopsied with the rigid instrument. In this situation,a disposable phosphate enema is superior to the small volumeMicrolax (Silverman and Keighley, 1985).

Colonoscopy and colonographyPolyethylene glycol electrolyte oral lavage was reportedto be superior to conventional purgation with enemas(Ernstoff et al, 1983). By contrast, radiologists find thatwhole gut irrigation leaves the colon too wet for optimummucosal coating (Skucas et al, 1976; Backran et al, 1977;Lee et al, 1981; Ernstoff et al, 1983). Traditional mechan-ical preparation may influence the histology of the colon

Risk Management 81

TABLE 3.12 EXAMPLES OF CONFUSING STATISTICAL INFORMATION, WITH ALTERNATIVESTHAT FOSTER INSIGHT

Type of information Examples How to foster insightSingle-event probabilities ‘You have a 30% chance of a side effect Use frequency statements: ‘Three

from this drug’ out of every 10 patients have a side effect from this drug’

Conditional probabilities The probability of a positive test result if Use natural frequencies, alone or the patient has the disease (sensitivity) together with conditional

The probability of a negative test result probabilitiesif the patient does not have the disease (specificity)

The probability of the disease if the patient has a positive test result (positive predictive value)

Relative risks If four out of every 1000 women (aged 40 Use absolute risks, alone or together or older) who do not undergo with relative risks: ‘In every 1000 mammography screening die of breast women who undergo screening cancer, compared with three out of every one will be saved from dying of 1000 who are screened, the benefit is breast cancer.’often presented as a relative risk: Use the number needed to treat or ‘Mammography reduces breast cancer harm: ‘To prevent one death from mortality by 25%.’ breast cancer, 1000 women need

to undergo screening for 10 years.’

From Gigerenzer and Edwards (2003).

and can be associated with flattening of the surface epithe-lial cells, goblet-cell depletion and increased oedema in thelamina propria (Gaginella and Phillips, 1976; Saunderset al, 1977; Meisel et al, 1977). By contrast, GoLytely wasassociated with minimal changes on light microscopy(Pockros and Foroozan, 1985). Fa-Si-Oen and Penninckx(2004) compared full-thickness surgical colonic biopsiesfrom 20 patients who received a normal meal the nightbefore surgery with biopsies from 20 patients that hadundergone colonic cleansing with polyethylene glycol.After assessing five microscopic criteria of damage to thecolonic wall the authors concluded that polyethylene gly-col caused no significant additional tissue damage. Othershave reported that sodium phosphate can produce aph-thous ulcers and that they are more common than inpatients prepared with polyethylene glycol electrolyte solu-tions (Hixson, 1995; Zwas et al, 1996). Nevertheless, theselesions have not been observed elsewhere (Curran andPlosker, 2004) either at endoscopy or from resection spec-imens (Kolts et al, 1993; Cohen et al, 1994; Oliveira et al,1997). Furthermore, oral whole-bowel irrigation is oftenpoorly tolerated and cannot be completed in a high pro-portion of patients (Burbridge et al, 1978; King et al, 1979;Thomas et al, 1982; Ernstoff et al, 1983; Adler et al, 1984;DiPalma et al, 1984; Kohler et al, 1990; Cohen et al, 1994;Chia et al, 1995; Oliveira et al, 1997).

Colonoscopy preparation with sodium phosphate hasbeen reported as superior to oral polyethylene glycol elec-trolyte lavage (Adams et al, 1994; Cohen et al, 1994; Chiaet al, 1995; Golub et al, 1995; Hookey et al, 2004; Curranand Plosker, 2004). Recently, however, a more com-plex triple regimen [senna syrup (sennoside B), Picolax(sodium picosulphate), and Klean Prep (polyethylene glycol3350)] appeared to be superior to Fleet Phospho-soda forcolonoscopy preparation, achieving better colonic cleans-ing (triple regimen 73%; Fleet phospho-soda 57%; P =0.037) (Chilton et al, 2000). Subsequently, a comparison ofbowel cleansing efficacy in patients having colonoscopy, hasbeen made between the standard polyethylene glycol-elec-trolyte solution based on the GoLytely formulation (PEG-EL1; Klean-Prep); a sulphate-free PEG-EL solution basedon the NuLytely formulation (PEG-EL2, Endofalk); and asodium phosphate preparation (NaP, Fleet Phospho-Soda).Among 185 patients randomly assigned to the three thera-pies PEG-EL1 (Klean-Prep) was significantly superior to PEG-EL2 (Endofalk) and NaP (Fleet Phospho-Soda) in achievingeffective cleansing of the entire colon prior to colonoscopy(Ell et al, 2003).

In a comparison of patient preference between the tech-niques of computed tomography (CT) colonography andconventional colonoscopy, bowel preparation was the fea-ture of both techniques most disliked by the patients stud-ied (Ristvedt et al, 2003). Lefere et al (2002) examined thefeasibility of detecting colonic polyps when a preparationof ‘reduced colonic’ cleansing had been employed—faecaltagging. The technique of faecal tagging was better toler-ated than conventional polyethylene glycol preparation andalso improved colonographic differentiation of polyps fromresidual stool. In virtual magnetic resonance colonogra-phy, faecal tagging is employed by either making the stoolbright (Gd-based MR contrast agent) in conjunction with

a ‘bright’ Gd-based enema or making the stool dark byadministering barium sulphate with each of four mainmeals 36 hours before the examination (Debatin andLauenstein, 2003). In the second strategy, the colon isdistended by a water enema. Intravenously administeredparamagnetic contrast then renders the colonic wall andcolorectal mass lesions bright. Therefore in the futurecolonography without colonic cleansing offers greaterpatient acceptability in diagnostic colonic studies (Herfarthand Schreyer, 2003).

Traditional preoperative methodsTraditional bowel preparation, which involves starvation,purgation, enemata and washouts, is time consuming,exhausting to the patient and demanding on nursing time,requiring supervision for some days before operation(Duthie et al, 1990; Santos et al, 1994):

● Food intake is discontinued for a variable period. Patientsare encouraged to drink plenty, both to avoid dehydrationand to overcome the feeling of hunger (Binder, 1977;Fingl and Freston, 1979). To avoid faecal residue, onlyclear fluids should be consumed, because low-residuediets result in the production of some faeces (Winitz et al,1966; Cooney et al, 1974; Johnson, 1974). Milk productsshould not be allowed and oral iron therapy must bediscontinued (Teague and Manning, 1977). This formof preparation is unsuitable for people with diabetes.

● Purgatives: magnesium salts have been used extensivelyin the past. These reduce sodium and water absorptionand produce some secretion into the lumen of the smallbowel, hence a large-volume hyperosmolar fluid load ispresented to the caecum. Consequently, although mag-nesium salts produce excellent clearance of the rightcolon, they cause considerable abdominal colic (Forthet al, 1972; Jauch et al, 1975). The dose of magnesiumsulphate varies from 5 to 15 g; in some institutions 10 mgis given 2-hourly on the day before operation. Magnesiumcitrate causes less colic and is usually effective using onlytwo 13 g doses. Sodium sulphate has a similar action tomagnesium citrate and inhibits sodium reabsorption(Tsang et al, 1992).

● Senna compounds are activated by colonic bacteria andhave no laxative effect until they reach the large bowel,hence clearance of the right colon is inferior to thatachieved with magnesium salts (Hardcastle and Wilkins,1970). Senna also causes vigorous mass contractions inthe colon, which result in some discomfort (Laurence,1973). Sodium picosulphate (10 mg), which is oftengiven with magnesium citrate (Picolax), is another purga-tive whose action depends on bacterial activation. Theanthraquinones such as bisacodyl or oxyphenisatin maybe given orally and are also activated by colonic bacteria.They may be given rectally as a stimulant enema.

● Castor oil may be used as a stool softener (Levy et al,1976; Beck et al, 1985) in a dose of 45 mL on theevening before operation, with saline enemata anda fluid diet (Margulis, 1967; Barnes, 1968; Irwin et al,1974). Alternatives to castor oil include dioctyl sodiumsulphosuccinate (100 mg 8-hourly for 3–4 days prior tothe enemata) and washouts.


● Most traditional preparations conclude with enemata and awashout. Saline enemata are said to cause less electrolytedisturbance than tap water or soap enemata (Turrell andLandau, 1959; Tyson and Spaulding, 1959; Mikal, 1965).Phosphate or bisacodyl enemata stimulate mass contrac-tion of the rectosigmoid. Corman (1993) considers that thetap water enema is the most important part of bowel prepa-ration and should be continued until the returns are com-pletely clear. The most aggressive form of distal clearanceis by the Henderson or Suda irrigating machines or usingpulsed irrigation evacuation (Kokoszka et al, 1994). Likemost forms of distal preparation, the quality is largely deter-mined by the commitment of the nurse. Both De Lacey et al(1982) and Lee and Ferrando (1984) came to the conclu-sion that these forms of rectal washout had no influenceon quality of preparation for barium enema. Furthermore,rectal washout produced a wet colon which resulted in poormucosal coating by barium.

Nasogastric whole-bowel irrigationIrrigation of the bowel with an electrolyte solution wasproposed for the treatment of cholera (Hewitt et al, 1973)and for the investigation of bidirectional ionic flux (Loveet al, 1968). The technique was subsequently modified asa method of bowel preparation. The procedure involvespassing a fine nasogastric tube. Intravenous metoclo-pramide may minimise nausea and accelerate gastricemptying (Crapp et al, 1975). Advancement of the tubethrough the pylorus does not alleviate distension andnausea (Christensen and Kronberg, 1981).

Walls (1980) recommended adding 90 g of salt to 10 Lof tap water and infused at a constant rate. After about 30minutes, the patient usually wants to defecate and shouldthen be seated on a commode. The preparation should notbe terminated until completely clear fluid has been passedfor at least half an hour. It is usually necessary to infuse10–12 L of fluid and the procedure takes between 4 and 6hours. If nothing is passed after 1 hour, if the patient’sabdomen becomes distended or if there is repeated vomit-ing, the infusion should be stopped, to avoid causingobstruction. Patients do not like this form of bowel prepa-ration (Downing et al, 1979) and, although whole-bowelirrigation still provides a high-quality bowel preparation,it is not superior to polyethylene glycol electrolyte solutionor sodium phosphate with bisacodyl (Wolters et al, 1994).

Isotonic saline (Hewitt et al, 1973), caused fluid andsodium retention with potassium loss and was contraindi-cated in patients with renal, cardiac or hepatic failure(Crapp et al, 1975). Gilmore et al (1981) recommended asolution containing less sodium (125 mmol/L) but includ-ing potassium and bicarbonate. Ringer’s lactate was there-fore recommended by those still enthusiastic about thetechnique (Wolters et al, 1994), but water retention ofbetween 1 and 8 L is a serious complication in patients withcardiac or renal disease.

Combining an osmotic agent with saline irrigationreduced the volume required (Donovan et al, 1980).Furthermore, the fluid and sodium retention which accom-panied saline lavage alone was eliminated when an osmoticagent was used before the saline irrigation (Minervini et al,1980a). A balanced electrolyte solution with polyethylene

glycol as an osmotic agent was developed and achievedan excellent quality of mechanical preparation with only4–5 L of fluid, so that the procedure could be completedin 2–3 hours without disturbance of fluid or electrolytebalance (Ambrose et al, 1983b).

Nasogastric whole-bowel irrigation using an osmoticagent and a balanced electrolyte solution is an excellentmethod of preparing the colon (Kohler et al, 1990). It isbetter than traditional bowel preparation (Christensen andKronberg, 1981) but the method is disliked by patients.Furthermore, the technique is contraindicated in acutecolitis, in megarectum with gross constipation and inobstructing tumours of the large bowel. An alternativeapproach, which reduces the duration of preparation, is touse Picolax before whole gut irrigation (Grace, 1988).

Oral whole-bowel irrigationElectrolyte solutionLevy et al (1976) proposed the use of an oral electrolytesolution by mouth. Patients found this extremely nauseat-ing and four of 37 patients could not complete the prepa-ration. Not surprisingly, patients also complained ofabdominal fullness. However, they found oral irrigation lessof an ordeal than traditional preparation.

Osmotic agentsNewstead and Morgan (1979) introduced the concept ofdrinking an osmotic agent. They chose the oligosaccharidemannitol because this is not absorbed during rapid transitthrough the small bowel, thereby achieving an osmoticcatharsis (Hindle and Code, 1962; Nasrullah and Iber,1969; Kreel, 1975; Nagy, 1981). However, it soon becameapparent that mannitol was associated with dehydrationand sodium loss (Gilmore et al, 1981). There were alsoreports of occasional fatal explosion with mannitol bowelpreparation, probably due to methane production as aresult of its fermentation by Escherichia coli (Bigarde et al,1979; Keighley et al, 1981; Taylor et al, 1981; Zanoni et al,1982). Mannitol was therefore discontinued.

Electrolyte solution and osmotic agentsGilmore et al (1981) suggested that if osmotic agents werecombined with an electrolyte solution there should be nofluid and electrolyte disturbance. A formulation that usedsodium sulphate was developed (Davis et al, 1980).Sulphate inhibits sodium reabsorption, thereby minimisingsodium and water retention. The mannitol was replaced bypolyethylene glycol, an inert, non-absorbable, non-fer-mentable compound that acted as the osmotic agent. Theformulation also included sodium bicarbonate to preventacidosis and some sodium supplements to minimise potas-sium loss. The formulation can be prepared in any phar-macy but it is now marketed in many different preparations,such as sulphate free, NuLytely, Calyte and CP100, many ofwhich are flavoured for improved palatability (Berry andDiPalma, 1994; Diab and Marshall, 1996).

Polyethylene glycol electrolyte solutions are safe andgenerally achieve a high quality of preparation (Kolts et al,1993; Lazzaroni et al, 1993; Chia et al, 1995). However,4 L of fluid must be taken, which some patients find diffi-cult to tolerate (Goldman and Reichelderfer, 1982; Thomas

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et al, 1982; Girard et al, 1984). There is no need to admin-ister metoclopramide (Rhodes et al, 1978) but bisacodylreduces the fluid intake from 4 to 2 L, which is easier forelderly patients to cope with, without compromising thequality of preparation (Adams et al, 1994). The risk ofexplosion is related only to the amount of faecal residue inthe colon and there is no disturbance in electrolyte balanceor acidosis (Ambrose et al, 1983b). The preparation is moreefficient than conventional preparation for colonoscopy(Rhodes et al, 1977; Thomas et al, 1982; Ernstoff et al,1983; DiPalma et al, 1984; Beck et al, 1985) but all formsof gut lavage seem to be disappointing when used for bar-ium enema examination (Skucas et al, 1976; Backran et al,1977; King et al, 1979; Ernstoff et al, 1983). Completionof a 4-L preparation is only achieved in 50–65% of patientsand causes considerable nausea and distress to manypatients (Vanner et al, 1990; Marshall et al, 1993; Adamset al, 1994; Chia et al, 1995; Golub et al, 1995).

Oral irrigation with electrolyte and polyethylene glycolis preferred by most patients to conventional preparationand nasogastric whole-bowel irrigation (Ambrose et al,1983b). However, in our experience, compliance is muchhigher with Picolax or sodium phosphate (Takada et al,1989; Yoshioka et al, 1998). Outpatient compliance to thepolyethylene glycol electrolyte solution is variable. Manyelderly patients will not drink a sufficient volume to ensurethat the faecal effluent is completely clear. The techniquemay also precipitate large bowel obstruction.

Purgation aloneSodium picosulphate and magnesium citrate (Picolax)Sodium picosulphate with magnesium citrate (Picolax)gives better results than either sennosides or mannitolbecause the right colon is cleared better (Lee and Ferrando,1984). In a randomised comparison of sodium picosulphatewith polyethylene glycol electrolyte lavage for colonoscopy,picosulphate was significantly better, with fewer side effectsand better bowel cleansing (Regev et al, 1998). Picolax issubstantially more effective than preparation with enemasand washouts (Roe et al, 1984). Tsang et al (1992) foundthat Picolax was superior to a balanced oral electrolytesolution (CP100) but inferior to sodium sulphate, which ismarginally less expensive. Clear fluids for 24 hours seemsessential to achieve an adequate bowel preparation.

Our practice has been to use Picolax exclusively, usingtwo sachets given 4 hours apart, 24 hours before opera-tion, endoscopy or double contrast barium enema, followedby clear fluids thereafter. Compliance is good and generallya high-quality preparation is achieved. Dehydration wascommon unless patients were given an intravenousinfusion or encouraged to take extra fluids (Takada et al,1993; Barker et al, 1992).

Sodium phosphateSodium phosphate is marketed as Fleet phospho-soda. Itsadvantage is that a much smaller volume is required com-pared with the polyethylene glycol electrolyte solutions: 45mL of the highly osmotic cathartic is mixed with 90 mL ofwater and taken twice (Chia et al, 1995). The only draw-back to sodium phosphate is the small risk of hyperphos-

phataemia and hypocalcaemia. Hyperphosphataemia isdose related and more common in patients with renal fail-ure (Afridi et al, 1995). Patients may encounter a modestreduction in serum potassium and increased serum sodiumwith sodium phosphate preparation (Lieberman et al,1996) and it is therefore contraindicated in congestive car-diac failure, ascites and renal failure (Aradhye & Brensilver,1991).

With the exception of a small colonoscopy study fromCalifornia (Marshall et al, 1993), most studies have foundthat sodium phosphate was cheaper, better tolerated, morelikely to be completed and more effective than polyethyleneglycol electrolyte lavage for bowel preparation (Vanner et al,1990; Kolts et al, 1993; Cohen et al, 1994; Chia et al, 1995;Golub et al, 1995; Hookey et al, 2004; Curran and Plosker,2004). A transient minor elevation of serum phosphate wasrecorded by some, who examined body composition, butthere were no recorded side-effects and calcium levels wereuninfluenced by the preparation. Sodium phosphate is thusgaining popularity for colonoscopy in the USA because of itscompetitive price, ease of administration and greater patientcompliance. It has also been recommended as the preparationof choice in a consensus statement on bowel preparation forcolonoscopy (Wexner et al, 2006). A trial to compare sodiumphosphate with polyethylene glycol based oral lavage alsoreported greater compliance, less pain, fatigue and bloatingwith comparable efficacy but both preparations resulted ina significant decrease in serum calcium (Oliveira et al,1997). Similarly, in a comparison of sodium phosphate withsodium picosulphate (Picolax), poor preparation was lesscommon in the sodium phosphate group (poor/awful 5/76,9%) than in the picosulphate group (poor/awful 13/73,18%; P = 0.084) (Yoshioka et al, 2000).

On-table preparationAntegrade irrigationPeroperative preparation is a method of ensuring that thecolon is empty prior to primary anastomosis. This proce-dure may be used either during an emergency operationfor bleeding, localised perforation or obstruction, or whenpreoperative bowel preparation is unsatisfactory (Muir,1968; Dudley et al, 1980).

IndicationsThe concept of intraoperative irrigation for large-bowelobstruction stems from the knowledge that staged proceduresare attended by a high mortality and a high permanentstoma rate, (Hughes, 1966; Fielding and Wells, 1974; Irvinand Greaney, 1977; Stewart et al, 1984; Phillips et al, 1985).The aim is therefore to resect diseased bowel and perform aprimary anastomosis after removing all faecal residue fromthe proximal colon.

Patients with localised sepsis from a walled-off perfora-tion of the colon constitute a group in whom on-tablelavage might also be advised because conventional bowelpreparation may result in a free perforation. If the proxi-mal colon can be rendered empty, a safe primary anasto-mosis can be performed (Mealy et al, 1988). In patientswith severe repeated colonic haemorrhage, on-table lavageshould facilitate total gut endoscopy and bleeding lesionsmay be more easily identified.


Technique● A large (no. 26) Foley catheter is inserted through a

purse-string suture placed in the caecum, either throughthe base of the appendix, if it is still present, or where thetaenia coli converge. Alternatively, and especially if a loopileostomy is to be raised a small ileostomy is made in theterminal ileum (at the site of the proposed stoma) and theFoley catheter is advanced through an ileostomy pursestring into the caecum for irrigation. The Foley catheteris attached to an infusion set and a 3-L bag ofHartmann’s solution (Munro et al, 1987). Some authorsuse tap water but there is a risk of excessive water absorp-tion if an isotonic solution is not used (Jones and Siwek,1986; Pollock et al, 1987).

● The entire colon, including both flexures, is mobilised, tak-ing great care not to injure the distended and obstructedbowel or to damage the vascular arcade. The bowel is iso-lated below the site of obstruction with a tape or curvedaortic clamp, and an on-table rectal washout is performeduntil the rectum is completely clean (see below).

● The bowel below the obstruction or locally perforatedbowel is divided. The colon is then delivered out of thewound. Colonic effluent is drained via anaesthetic scav-enger tubing, connected to a transparent plastic bag ora purpose-built unit (Koruth et al, 1985b), inserted intothe proximal colon through the purse-string and securedby a second nylon tape (see Figure 3.5). Irrigationthrough the Foley catheter can now commence. The irri-gation fluid should be at room temperature. Jones andSiwek (1986) use a mercuric perchloride rectal irrigationat the completion of the proximal colonic lavage. Pollocket al (1987) use 10% povidone–iodine through the prox-imal colon as a ‘last wash’ (Banich and Mendak, 1989).

● If anaesthetic tubing is used to collect the distal effluent itmay be necessary to break-up any solid faecal matter in thedescending colon to allow it to pass through the tubing intothe collecting bag and to vent the tubing with a wide-boreneedle if a negative pressure develops in the closed irriga-tion system. An alternative lavage technique involves open-ing the colon just above the lesion through a longitudinalcolotomy so that the solid and liquid stool can be rapidlydirected into a bowl held to the side of the wound, the colo-tomy and colonic lesion both being included in the resectedspecimen. The irrigation should continue until clear efflu-ent emerges and the whole procedure should not take anylonger than 20 minutes. A stapled or sutured anastomosisshould be possible with an empty rectum and proximalcolon (Koruth et al, 1985b). Some authors advise decom-pressing the anastomosis (tube ileostomy or tube caecos-tomy, depending on the site of enterotomy) by inflating theballoon after securing the serosa of the bowel to the pari-etal peritoneum and the catheter to the abdominal wall.However, we much prefer a loop ileostomy if the bowelpreparation has been successful.

● There are several reported series of patients who have hadantegrade on-table colonic irrigation; most of these stud-ies are not confined to patients with acute obstruction butinclude those in whom preoperative bowel preparationwas inadequate. The mortality in patients having primaryresection and anastomosis under emergency surgical con-

ditions with on-table lavage ranges from 0% to 17%,specifically: 3% (Radcliffe and Dudley, 1983), 13%(Koruth et al, 1985a), 4% (Thomson and Carter, 1986),3% (Weaver and Khawaja, 1986), 17% (Pollock et al,1987) and 0% (Maher et al, 1996).

Rectal washoutOn-table rectal washout should always be a therapeuticoption when operating on the left colon or rectum.Accordingly, all patients should be placed in the LloydDavies position and a large (no. 30) Foley catheter insertedinto the rectal ampulla.

IndicationsIf a stapled rectal anastomosis is used, rectal washout isadvised if the bowel is unprepared or where preparation ispoor, to ensure that the rectal ampulla is free from any fae-cal material. Passage of a stapling instrument through aninadequately prepared rectal ampulla increases the risk ofpelvic contamination.

TechniqueThe rectum is cross-clamped after full mobilisation and, inthe case of rectal cancer, the clamp should be applied justbelow the tumour. The washout is performed using ano. 30 Foley catheter or, if very low, a 50-mL syringe, andshould continue until the effluent is clear of faecal residue(see Figure 3.6). For mid-rectal cancers, an alternativetechnique is to staple the rectum below the tumour, per-form the distal washout and then place a second stapleline a further 1–2 cm distally beyond the first staple lineand divide the bowel at this point through lavaged rec-tum. Washout with povidone–iodine achieves a significantreduction in the aerobic counts within the rectal ampulla,0.3% hypochlorite solution eliminated both aerobes andanaerobes from the rectal stump (Scammell et al, 1985).There is no evidence that rectal washout reduces the anas-tomotic leak rates after low anterior resection (Cade, 1981;Tagart, 1981).

Efficacy and surgery: the authors’ viewBowel preparation is probably still practised by most sur-geons performing elective colorectal operations in thebelief that it is a safe technique and that sepsis and anas-tomotic breakdown may be minimised by operating onan empty colon (Nichols and Condon, 1971). However,this concept has been challenged in recent years (Irvingand Scrimgeour, 1987). Thus series that describe goodresults following the immediate repair of colonic pene-trating trauma without mechanical colonic cleansing,have brought into question the relevance of electivebowel preparation (Curran and Borzotta, 1999; Conradet al, 2000). Before assuming that mechanical bowelpreparation is desirable, the impact of bowel preparationon infections, anastomotic dehiscence and safety mustbe assessed critically.

SafetyIt is important that mechanical bowel preparation is safeand does not cause unnecessary discomfort or anxiety to

Risk Management 85


c

a

b

Figure 3.5 On-table colonic lavage in progress. (a) Anelectrolyte solution at body temperature is being irrigatedthrough an appendicostomy purse-string and solid faecalresidue is being irrigated from the colon proximal to thetumour through the anaesthetic scavenger tubing which drainsinto a plastic bag below the operating table. (b) Commerciallyavailable device for achieving on-table colonic lavage toachieve rapid volume irrigation. (c) Commercially availabletechnique for collecting effluent to minimize contaminationand to provide a method of venting.

the patient. Special consideration (Valantas et al, 2004)needs to be given to elderly patents undergoing bowelpreparation with respect to:

● Nursing-home residents with impaired mobility, impairedsphincter function and coexisting problems with diar-rhoea or constipation.

● Obtunded patients, who should not be given lavage prepa-rations.

● Avoiding magnesium citrate in patients with renal fail-ure.

● Not giving a phosphate load to patients with renal, car-diac or hepatic insufficiency.

Vigorous mechanical bowel preparation may occasionallybe complicated by perforation and bacteraemia, hence theuse of bowel preparation should be avoided in acute colitisand possibly in patients with a localised pericolic abscess(Galloway et al, 1982).

Reducing the risk of sepsisAlthough it is assumed that a clean colon is associated witha significant reduction in sepsis, the evidence that this istrue among patients having mechanical preparation alone,without antibiotic cover, is lacking (Burton, 1973). If anefficient method of bowel preparation is used with antibi-otic cover, the quality of bowel preparation is an inde-pendent variable in reducing sepsis (Morris et al, 1983).There are some forms of mechanical bowel preparation,such as the oligosaccharide mannitol, that may increasethe risk of sepsis (Hares et al, 1981a). Previous clinical

series have suggested that efficient mechanical bowelpreparation will protect against the risk of sepsis if it iscombined with some form of systemic antibiotic cover(Chung et al, 1979; Gottrup et al, 1985; Panton et al,1985; Raahave et al, 1986). In this regard, oral whole-bowel irrigation or nasogastric irrigation is not necessarilysuperior to traditional forms of preparation in minimisingsepsis (Christensen and Kronberg, 1981; Fleites et al,1985).

But does mechanical bowel preparation have a role inreducing wound sepsis or anastomotic leaks after colorec-tal surgery? Jansen et al (2002) report on 102 consecutiveelective right hemicolectomies or extended right hemi-colectomies for colorectal cancer. All underwent resectionover a 10-year period without bowel preparation. Therewere no leaks, two wound infections and one death (anas-tomosis intact at autopsy). Vlot et al (2005) reported on144 patients who underwent an elective (low) anteriorresection between January 1996 and December 2001 andneither had mechanical bowel preparation nor a coveringloop ileostomy. Anastomotic leakage occurred in seven outof 144 patients (4.9%). There was a trend toward a higherleakage frequency in men, in patients with a distal anas-tomosis, in patients with a stapled anastomosis, and inpatients with a T3–T4 tumour or with positive lymphnodes.

Bucher et al (2005) studied patients scheduled forelective left-sided colorectal resection with primary anas-tomosis randomised to preoperative mechanical bowelpreparation (3 L polyethylene glycol) (group 1) or

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Figure 3.6 On-table rectal washout. Thepatient is in the Lloyd–Davies position.Bowel clamps have been placed belowthe obstructing lesion. A Foley catheterhas been inserted into the rectal stump.The rectal stump is being irrigated withan antiseptic solution.

surgery without mechanical bowel preparation (group 2).Postoperative abdominal infectious complications andextra-abdominal morbidity were recorded prospectively.One hundred and fifty-three patients were included in thestudy, 78 in group 1 and 75 in group 2. The overall rate ofabdominal infectious complications (anastomotic leak,intra-abdominal abscess, peritonitis and wound infection)was 22% in group 1 and 8% in group 2 (P = 0.028).Anastomotic leak occurred in five patients (6%) in group1 and one (1%) in group 2 (P = 0.210). Extra-abdominalmorbidity rates were 24% and 11% for bowel preparationor no preparation, respectively (P = 0.034). Hospital staywas longer for patients who had mechanical bowel prepa-ration [mean (s.d.) 14.9 (13.1) versus 9.9 (3.8) days; P =0.024].

Reducing the risk of anastomotic breakdownEarly evidence from clinical series suggested that the qual-ity of mechanical bowel preparation was closely related toanastomotic dehiscence (Rosenberg et al, 1971). Irvin andGoligher (1973), in their retrospective review of 204 hand-sutured large-bowel anastomoses, showed that the mostpowerful determinant of anastomotic leakage was thequality of mechanical bowel preparation. There were nineleaks from 116 anastomoses when mechanical prepara-tion was of good quality (8%), compared with 19 leaksfrom 59 anastomoses when faecal residue was present atthe operation (32%). Morris et al (1983) reported anasto-motic leaks or perianastomotic abscess in 1 of 76 patientswho had a good bowel preparation compared with 6 of 13in those in whom there was gross faecal residue in thecolon. Similar observations have been made by others(Schrock et al, 1973; Walls, 1980; Christensen andKronberg, 1981). Animal studies indicate that the burst-ing pressure at a colonic anastomosis is reduced if there isincreased faecal residue (Smith et al, 1983; O’Dwyer et al,1989), possibly due to increased collagenase activity(Hawley et al, 1970a,b; Ryan, 1970).

More recently, this issue has been addressed in the set-ting of randomised clinical trials. Miettinen et al (2000)randomised 267 patients admitted for colorectal surgery toeither oral polyethylene glycol electrolyte solution (n = 138)or no preparation (n = 129). Patients who were unable todrink the polyethylene glycol electrolyte solution or who hadhad bowel preparation in the previous week were excluded.There were no differences in outcome between the twogroups: anastomotic leaks were 4% in the oral preparation

group versus 2% in the no preparation group; other surgi-cal site infections were 6% in the oral preparation group ver-sus 5% in the no preparation group. Similarly, Ram et al(2005) could find no advantage for mechanical bowelpreparation in a randomised controlled trial (RCT) ofpatients undergoing elective colorectal surgery.

Zmora et al (2003a) recruited 415 patients into groupsfor comparison of the effect of bowel preparation on post-operative sepsis: group A received 1 gallon of polyethyleneglycol 12–16 hours before surgery (n = 187), group Breceived no preoperative bowel cleansing (n = 193). Thegroups were identical for demographics, indications forsurgery and type of surgery. After randomisation, 29patients were excluded (18 APR, 11 proximal stoma).Spillage of bowel content (Zmora et al, 2003b) was signi-ficantly more common in group A than group B. However,there was no difference in the two groups in the rateof postoperative wound infections, clinical anastomotic leaksor intra-abdominal abscesses (Table 3.13). One patient ineach group died from sepsis related to an anastomoticleak.

Slim et al (2004) conducted a meta-analysis of RCTs ofmechanical bowel preparation that identified 11 studies,of which seven were felt to be suitable for inclusion. Themethodological quality of each trial was assessed for ran-domisation (Table 3.14), blinding and withdrawals ordropouts; a trial was considered poor when it scored 2 orless. The final meta-analysis for anastomotic leakage as theoutcome related to bowel preparation showed a negativeoutcome for bowel preparation. Slim et al (2004) con-cluded that there was significantly higher incidence ofleaks in the preparation group than in the control group(5.6% versus 3.2%; OR 1.74 (95% CI 1.05 to 2.90;P = 0.032). They also concluded that wound infection washigher after bowel preparation although not significantlyso (7.4% versus 5.7%; OR 1.33; 95% CI 0.88–2.03).

Bucher et al (2004), in a meta-analysis, examined sevenRCTs constituting 1297 patients undergoing elective col-orectal surgery (642 who had received mechanical bowelpreparation and 655 who had not). Among all the RCTsreviewed, anastomotic leak was significantly more frequentin the mechanical bowel preparation group (35/642 =5.6%), compared with the no mechanical bowel prepara-tion group (18/655 = 2.8%) (OR 1.84; P = 0.03). By con-trast, rates of intra-abdominal infection (3.7% for themechanical bowel preparation group versus 2.0% for theno mechanical bowel preparation group), wound infection


TABLE 3.13 RANDOMISED TRIAL OF PEG vs. NO PREPARATION

Group A: (n =187) Group B: (n =193)bowel no bowel

preparation preparation P valueAnastomotic leak 7 (3.7%) 4 (2.1%) NSIntra-abdominal abscess 2 (1.1%) 2 (1%) NSWound infection 12 (5.4%) 11 (5.7%) NSTotal 19 (10.2%) 17 (8.8%) NS

After Zmora et al (2003a).

NS, not significant.

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TABLE 3.14 META-ANALYSIS OF IMPACT OF BOWEL PREPARATIONON ANASTOMOTIC LEAK RATES

Quality Leaks in prepared Leaks in score patients non-prepared patients

Brownson et al, 1992 2 8/67 1/67Santos et al, 1994 4 7/72 4/77Burke et al, 1994 3 3/82 4/87Miettinen et al, 2000 4 5/138 3/129Fillman et al, 2001 4 2/30 1/30Zmora et al, 2003a 4 7/187 4/193Fa-Si-Oen 2003 2 7/125 6/125Total 39/701 23/708

After Slim et al (2004).

(7.5% for the mechanical bowel preparation group versus5.5% for the no mechanical bowel preparation group), andreoperation (5.2% for the mechanical bowel preparationgroup versus 2.2% for the no mechanical bowel prepara-tion group) were not significantly different.

In the most recent Cochrane review (Guenaga et al,2005; Wille-Jørgensen et al, 2005) of mechanical bowelpreparation in elective colorectal surgery, nine RCTs involv-ing 1592 patients were identified. Of these, 789 were allo-cated to mechanical bowel preparation (group A) and 803to no preparation (group B) before elective colorectal sur-gery. For anastomotic leakage (the main outcome) theresults were:

● Low anterior resection: 9.8% (11 of 112 patients in groupA) compared with 7.5% (9 of 119 patients in group B);Peto OR 1.45; 95% CI 0.57–3.67; not significant.

● Colonic surgery: 2.9% (group A) compared with 1.6%(group B); Peto OR 1.80; 95% CI 0.68–4.75; not signifi-cant.

● Overall anastomotic leakage: 6.2% (group A) comparedwith 3.2% (group B); Peto OR 2.03; 95% CI 1.276–3.26;P = 0.003).

For the secondary outcome of wound infection, the resultswere: 7.4% (group A) compared with 5.4% (group B); PetoOR 1.46, 95% CI 0.97–2.18; P = 0.07.

In our view, the place of mechanical bowel prepara-tion as a technique to prevent anastomotic leakage andpostoperative wound sepsis must be called into doubt bythese findings. However, the widespread abandonmentof mechanical bowel preparation in all colorectalresections should be viewed with some caution. Thedefinitive randomised study (assuming an infectiouscomplications rate of 10%), for a prospective study thatwill be able to detect a difference of 5% in infection rate,in a one-tailed statistical test, assuming an alpha levelof 0.05, with a statistical power of 90%, 770 patientswould be required to be randomised to each group(Zmora et al, 2003b).

We would concur with Zmora and Habr-Gama (2004)that mechanical bowel preparation still has a place in themanagement of patients undergoing colorectal resection—especially low rectal cancer extirpation. Whereas thisprobably does not apply to right hemicolectomy, we

would continue to advocate the use of mechanical bowelpreparation in the following two circumstances:

● all patients in whom on table colonoscopy may form partof the operative procedure

● all patients in whom a distal anastomosis might requirea proximal defunctioning stoma.

● all patients having an ultralow anterior resection.

COLORECTAL SURGERY AND SURGICALSITE INFECTIONSDefinition and surveillanceWound infection or surgical site infection causes a sub-stantial degree of illness and, in some cases, patient death(Wilson et al, 2004). Hospital discharge is delayed and, asa result, this complication alone produces a significantincrease in health-care costs: infected surgical wounds costthe NHS over £62 million in 1995 (Plowman et al, 2001).

The definition of surgical site infection remains prob-lematic. There are currently at least four common defini-tions in use (Wilson et al, 2004):

● 1992 Centers for Disease Control (CDC) definition: 16wound or patient characteristics in the surgeon’s diag-nosis of infection plus culture of microorganisms fromthe wound.

● US National Nosocomial Infections Surveillance System(NINSS): as above but the NINSS criteria to be based onpositive cultures of tissue and fluid rather than woundswabs.

● ‘English’ NINSS: modified CDC definition to exclude theneed for surgeon’s diagnosis and requires pus cells to bepresent to satisfy the criterion of microorganisms culturedfrom the wound.

● ASEPSIS: quantitative scoring method that provides anumerical score related to the severity of the wound infec-tion using objective criteria based on wound appearanceand clinical consequences.

Wilson et al (2004) examined 5804 surgical wounds froma variety of specialties and found that the mean percent-age of wounds classified as infected differed substantiallywith different definitions: 19.2% with the CDC definition(95% CI 18.1–20.4%), 14.6% (13.6–15.6%) with theNINSS version, 12.3% (11.4–13.2%) with pus alone and

6.8% (6.1–7.5%) with an ASEPSIS score > 20. In addition,the agreement between definitions with respect to individ-ual wounds was poor. Thus, whereas a single definition ofsurgical site infection used consistently can show changesin wound infection rates over time at a single centre,differences in interpretation may prevent comparisonbetween centres. Similarly, Bruce et al (2001) using a sys-tematic review of prospective studies of surgical woundinfection published over a 7-year period (1993–9), identi-fied extensive variation in the definition of surgical woundinfection used in clinical practice.

In the UK, the Department of Health and the PublicHealth Laboratory Service have established a NINSS inEngland. Hospitals are required to collect data over a min-imum of 3 months, data collection being coordinated bythe Infection Control Team in each hospital (Wilson et al,2002). Infection Control Teams have shown considerablesupport for this approach, with results being passed backto clinicians and managers. As a result, two-thirds of hos-pitals have reviewed or changed clinical practice (Wilsonet al, 2002). The responsibility for conducting this exerciseis now with the Health Protection Agency, which hasdefined the categories for surgical site infection surveillance.For large bowel surgery these are: incision, excision or anas-tomosis of the large bowel including procedures that involveanastomosis of the small to large bowel. The definitions ofsurgical site infection are given in (Table 3.15).

A NNIS risk index has been developed to stratify the riskof surgical site infection, each operation being scored bythe presence or absence of three risk factors at the time ofsurgery:

● ASA of > 2.● Operation classified as contaminated or dirty.● An operation lasting for a specific period of time (T hours)

where T is the 75th percentile of the duration of surgeryand depends on the surgical procedure being performed(for large bowel surgery, T = 3 hours).

Each of the risk factors contributes one point to the riskindex, which therefore ranges from 0 to 3 (if all risk factorspresent) (Health Protection Agency, 2004).

Table 3.16 shows the the distribution of surgical siteinfection rates and risk index category in the AmericanNational Nosocomial Infections Surveillance (NNIS)System Report (2003).

Surgical site infection prophylaxisOperating room routineQuite apart from surgical technique, operating theatre dis-cipline is believed by many to reduce the risk of contami-nation, and consequently the incidence of sepsis (Hughes,1972; Krukowski et al, 1984). In the UK and USA, povi-dine–iodine and chlorhexidine gluconate are the scrubagents of choice for the surgical team (Mangram et al,1999). No clinical trials have evaluated the impact of thescrub agent on surgical site infections. The first scrub ofthe day should include a thorough cleaning underneaththe fingernails usually with a brush. A 2-minute scrub maybe as effective as a 10-minute scrub in reducing bacterialcolony counts but the optimum duration is not known(Mangram et al, 1999). Parienti et al (2002) compared two

hand-cleansing methods alternately every other month:a hand-rubbing protocol with 75% aqueous alcoholicsolution containing propanol-1, propanol-2 and mecetro-nium etilsulfate, and a hand-scrubbing protocol with anti-septic preparation containing 4% povidone–iodine or 4%chlorhexidine gluconate. Thirty-day surgical site infectionrates were 55 of 2252 (2.44%) in the hand-rubbing pro-tocol and 53 of 2135 (2.48%) in the hand-scrubbing pro-tocol, a difference of 0.04% (95% CI 0.88–0.96%). Thushand-rubbing with liquid aqueous alcoholic solution canbe safely used as an alternative to traditional surgical handscrubbing.

Wearing finger rings and nail polish was thought toreduce the efficacy of the scrub as these are thought toharbour bacteria (in microscopic imperfections of nail pol-ish and on the skin beneath finger rings). However, in aCochrane review, no RCTs measured patient outcomes,including surgical infection, with the wearing of fingerrings versus the removal of finger rings and there were notrials of nail polish wearing versus removal (Arrowsmithet al, 2001). In a further small RCT, nurses were allocatedto: unpolished nails, freshly applied nail polish (less than 2days old), or old nail polish (more than 4 days old). Bothbefore and after surgical scrubbing, there was no signifi-cant difference in the number of bacteria on the hands.However, the wearing of artificial nails has been associatedwith isolated outbreaks of surgical site infection (Passaroet al, 1997).

Although the use of barriers to separate the surgicalfield from the live organisms shed by the surgical teamseems prudent, there are few controlled studies to supportthe use of scrub suits and other covering attire (Mangramet al, 1999). Clinical series demonstrate that the use oftightly woven special scrub suits reduces the dispersal oftotal counts of bacteria and of Staphylococcus aureus fromstaff in the operating room, thus possibly reducing the riskof airborne contamination of surgical wounds (Tammelinet al, 2001). Surgical site infections have been linked toorganisms shed from the hair or scalp and therefore capsand hoods reduce surgical field contamination (Mangramet al, 1999). A recent Cochrane review of randomised stud-ies of facemask versus non-facemask use concluded that itremains unclear as to whether wearing a surgical facemask results in any harm or benefit to the patient under-going clean surgery (Lipp and Edwards, 2002). Shoe coversor operating room restricted shoes transfer fewer bacteriaonto a disinfected floor area than do unprotected streetshoes (Copp et al, 1987). However, the use of shoe covershas not been shown to decrease surgical site infections(Mangram et al, 1999).

Sterile gloves have the dual role of stopping transmis-sion of bacteria from the surgical team to the patient andprevent contamination of the team members’ hands by thepatient’s blood and body fluids. Perforation of the latexsurgical glove negates this dual barrier and has led to thepractice of double gloving. A Cochrane systematic review(Tanner and Parkinson, 2002) has concluded that wear-ing two pairs of latex gloves significantly reduces the num-ber of perforations to the innermost glove. This evidencecomes from trials undertaken in ‘low risk’ surgical spe-cialties, i.e. specialties that do not include orthopaedic joint


Risk Management 91

TABLE 3.15 DEFINITION OF SURGICAL-SITE INFECTIONS

Superficial incisional infectionDefinition Surgical site infection that occurs within 30 days of surgery and involves only the skin or

subcutaneous tissue of the incision and meets at least one of the following criteria:Criterion 1 Purulent drainage from the superficial incisionCriterion 2 The superficial incision yields organisms from the culture of aseptically aspirated fluid or tissue

or from a swab with pus cells presentCriterion 3 At least two of the following symptoms and signs

● Pain or tenderness● Localised swelling● Redness● Heat and:

● the superficial incision is deliberately opened by a surgeon to manage the infection, unlessincision culture is culture-negative

or:● the clinician diagnoses a superficial incisional infection

Important note Stitch abscesses: these are defined as minimal inflammation and discharge confined to the points of suture penetration and localised infection around a stab wound, They are notclassified as surgical site infections

Deep incisional infectionDefinition Surgical site infection involving the deep tissues (i.e. fascial and muscle layers) that occurs

within 30 days of surgery if no implant is in place or within a year if an implant is in place andthe infection appears to be related to the surgical procedure and meets at least one of thefollowing criteria:

Criterion 1 Purulent drainage from the deep incision but not from the organ/space component of the surgical site

Criterion 2 The deep incision yields organisms from the culture of aseptically aspirated fluid or tissue or from a swab with pus cells present

Criterion 3 A deep incision that spontaneously dehisces or is deliberately opened by a surgeon when the patient has at least one of the following symptoms or signs:

● Fever (> 38˚C)● Localised pain or tendernessUnless the incision is culture negative

Criterion 4 An abscess or other evidence of infection involving the deep incision that is found by direct examination during reoperation or by histopathological or radiological examination

Criterion 5 Diagnosis of a deep incisional surgical site infection by an attending clinicianImportant note An infection that involves both superficial and deep incision is classified as deep inicisonal

surgical site infection

Organ/space infectionDefinition Surgical site infection involving any part of the anatomy (i.e. organ/space) other than the

incision, opened or manipulated during the surgical procedure, that occurs within 30 days ofsurgery if no implant is in place or within a year if an implant is in place and the infectionappears to be related to the surgical procedure and meets at least one of the following criteria:

Criterion 1 Purulent drainage from a drain that is placed through a stab wound into the organ/spaceCriterion 2 The organ/space yields organisms from the culture of aseptically aspirated fluid or tissue or from

a swab with pus cells presentCriterion 3 An abscess or other evidence of infection involving the organ/space that is found by direct

examination during reoperation or by histopathological or radiological examinationCriterion 4 Diagnosis of an organ/space surgical site infection by an attending clinicianImportant notes 1. Occasionally an organ/space infection drains through the incision. Such infection generally

does not require reoperation and is considered to be a complication of the incision and istherefore classified as a deep incisional infection

2. Where doubt exists refer to the definitions of specific site of organ/space infection to determine if the organ/space infection meets the definition

From Health Protection Agency (2004) http://www.hpa.org.uk/infections/topics_az/hai/menu.htm

surgery. Wearing two pairs of latex gloves does not causethe glove wearer to sustain more perforations to their out-ermost glove. Wearing double latex indicator gloves enablesthe glove wearer to detect perforations to the outermostglove more easily than when wearing double latex gloves(Tanner and Parkinson, 2002). Furthermore, changingsurgical gloves before wound closure has been shown to beassociated with significantly fewer wound infections (2/46= 5.5% gloves changed; 9/46 = 25% gloves not changed)in a randomised comparison of women undergoingcaesarean section (Ventolini et al, 2004).

Skin preparationMost colorectal surgeons accept the need for antisepticskin preparation as well as antibiotic prophylaxis as pro-tection against bowel contamination during resection(Ambrose et al, 1983a; McDonald et al, 1984). Skin prepa-ration should be performed with two applications of analcohol-based preparation, which should be given ade-quate time to dry between applications (Lilly and Lowbury,1971; Lowbury and Lilly, 1973; Lowbury et al, 1974).Hexachlorophane may cause hypersensitivity reactions(Cruse and Foord, 1973); chlorhexidine or iodine solutionsin an alcohol base are usually preferred. In a Cochranesystematic review (Edwards et al, 2004), six eligible RCTsevaluating preoperative antiseptics were identified.Significant heterogeneity meant that comparisons and theresults could not be pooled. In one study, infection rateswere significantly lower when skin was prepared usingchlorhexidine compared with iodine. There was, however,no evidence of a benefit in four trials associated with theuse of iodophor impregnated drapes. The current view isthat there is insufficient research examining the effects ofpreoperative skin antiseptics to allow conclusions to bedrawn regarding their effects on postoperative surgicalwound infections (Edwards et al, 2004).

Surgical techniqueSimple matters, such as ensuring that division of the bowelis the last event in a colonic resection, and the use ofoccluding tapes and staples reduce the duration and theextent of contamination (Keighley et al, 1996). Ensuringthat an adequate sucker is available when the bowelis divided and the use of large gauze swabs soaked in anantiseptic solution helps to minimise contamination (Rietz

et al, 1984). Other simple measures include protecting theend of the bowel prior to construction of a stoma with aclamp or by staples to reduce contamination of the woundand the stoma trephine. In addition the stoma should notbe constructed until the abdominal incision has been closedand covered.

Gentleness in handling tissues, adequate perfusion ofthe gut and avoidance of local ischaemia are importantsurgical principles (Fawcett et al, 1996). Avoidance of ten-sion at an anastomosis or a stoma and preserving an ade-quate blood supply to the colon are crucial. Other surgicalexpedients, such as avoiding an anastomosis if there isgross contamination or established infection, cannot beoverstressed (Fikri and McAdams, 1975; Hughes et al,1982; Krukowski and Matheson, 1983; Ahrendt et al,1994, 1996). Using these principles, Krukowski et al(1984) reported an infection rate of only 1.8% in electivecolorectal surgery and a rate of 6.7% in emergency proce-dures. Synchronous surgical procedures increase the riskof sepsis (Simchen et al, 1984).

Techniques to limit surgical site infections include theuse of drains after colorectal anastomosis to reduce orprevent accumulation of fluids particularly blood in thepelvic or peritoneal cavity and to permit early detectionof anastomotic dehiscence by faecal or purulent dischargefrom the drain. However, Brown et al (2001) could notshow any difference in morbidity between patients thatdid and those that did not receive a drain after infraperi-toneal colorectal anastomosis. The French Association forSurgical Research (Merad et al, 1999) conducted a largerandomised trial of 494 patients undergoing resection forcolorectal cancer, benign neoplasm, colonic Crohn’s dis-ease and diverticular disease of the sigmoid colon followedby colorectal anastomosis. Patients were randomised toeither drainage (n = 248) with two multiperforated 14Fsuction drains or no drainage (n = 246). The incidence ofanastomotic leakage, postoperative reoperation and post-operative death were no different between the two groups.In a Cochrane systematic review of surgical drains inelective colorectal surgery (Jesus et al, 2004), of the 1140patients enrolled (six RCTs), 573 were allocated fordrainage and 567 for no drainage. The patients in the twogroups had very similar outcomes in terms of postopera-tive complications and deaths (Table 3.17). Others(Urbach et al, 1999; Petrowsky et al, 2004)—usinglargely the same RCT evidence in a meta-analysis—havesimilarly concluded that routine prophylactic drainageprovides no benefit after uncomplicated major colon andrectal surgeries.

At the conclusion of the procedure and before stoma for-mation, a wound dressing is used to cover the closed inci-sion for 24–48 hours (Mangram et al, 1999). The evidenceas to which type of wound dressing best prevents surgicalsite infection is very limited. Holm et al (1998), in a verysmall study of clean wounds, found no difference in infec-tion rates when two dressing techniques—Mepore andComfeel—were compared. Burrows (2000) included thislatter study and two others in an attempt to answer thequestion as to whether occlusive or non-occlusive dress-ings best reduced infections in surgical wounds. From theresults of three trials analysed, it was concluded that the


TABLE 3.16 DISTRIBUTION OF SURGICALSITE INFECTION RATES AND RISK INDEXCATEGORY

Risk Number Pooled index of mean

category hospitals rateColon 0 94 4.0%Colon 1 102 5.64%Colon 2 81 8.55%Colon 3 27 11.53%

National Nosocomial Infections Surveillance (NNIS) System

Report (2003).

use of occlusive dressings was not associated with a reduc-tion in wound infection rates but that larger trials wereprobably required if a significant difference was to bedetected. Similarly, the need for wound dressing after 48hours has not been supported by a reduced infection ratein a comparison of two groups of 50 patients each (Meylanand Tschantz, 2001).

Intraoperative antisepticsAntiseptics can damage small blood vessels, collagen syn-thesis and rapidly dividing cells (Brennan et al, 1986).Kuijpers (1985) questioned the wisdom of using povi-done–iodine in patients with peritonitis, because this cancause serious peritoneal damage. However, it can be usefulif there has been inadvertent faecal contamination(Browne and Stoller, 1970; Gilmore et al, 1978b;Ahrenholz and Simmons, 1979; Flint et al, 1979; Sindelarand Mason, 1979). Most authorities believe that antisep-tic lavage is unsafe if there is established inflammation, asin faecal or purulent peritonitis (Lagarde et al, 1978;McAvinchey et al, 1983). Neither continuous salinenor antiseptic lavage influenced postoperative sepsis in colorectal surgery (Hallerback and Andersson, 1986;Leiboff and Soroff, 1987; Baker et al, 1994).

Intraluminal antiseptics may be used for rectal washoutsas they reduce the counts of luminal bacteria (Jones et al,1976; Scammell et al, 1985). Povidone–iodine rectalwashout can be extended in a retrograde fashion to thewhole colon: 1 L reaches the caecum in 2 minutes (Marianiet al, 2002). Although the use of povidone–iodine in thisfashion is associated with increased systemic iodine absorp-tion, it appears that a single intraoperative bowel irrigationwith povidone–iodine may be performed with practicallyno risk (Tsunoda et al, 2000).

Antiseptics have been applied to the wound at the endof the operation to minimise the consequences of inadver-tent contamination (Gilmore and Sanderson, 1975;Gilmore, 1977; Stokes et al, 1977; Gilmore et al, 1978a;Sindelar and Mason, 1979; Galle and Homersley, 1980; deJong et al, 1982). A more recent extension of this approachhas been the development of antiseptic wound ventilationwith a combination of CO2 and 95% ethanol (Persson et al,2003). On filter disks, CO2 carrying vapour from a 95%

ethanol solution decreased the number of colony-formingunits after 5 min of exposure (P = 0.04), and killed allbacteria within 10–15 min (P < 0.001).

Optimising the wound environmentThe wound environment is increasingly recognised as hav-ing a key role in determining its susceptibility to surgicalsite infection. Obesity is associated with an increased inci-dence of wound-site infection. Tsukada et al (2004) cal-culated the intra-abdominal fat area (IAF) and thesubcutaneous fat area (SCF) for 139 patients undergoingelective gastric or colorectal cancer surgery using a CT scanof the abdomen performed at the level of the umbilicus.The IAF area was quantified by delineating the border ofthe peritoneal cavity and was computed as the area withan attenuation range of −250 to −50 Hounsfield units. Theabdominal SCF area was calculated by subtracting the vis-ceral fat area from the total abdominal fat area. Using thecriteria of Japan Society for Study of Obesity, the IAF cut-off point was 160 cm2 for males and 120 cm2 for females,and SCF cut off point was 180 cm2 for males and 250 cm2

for females. Nineteen patients (Tsukada et al, 2004) hadsurgery-related complications (anastomotic leakage, intra-abdominal collections or abdominal wound infection) andthese were significantly associated with IAF and SCF val-ues greater than the cut-off points. Kabon et al (2004) hassubsequently demonstrated that intraoperative subcuta-neous tissue oxygen tension is significantly less in obesepatients (BMI > 30 kg/m2) at baseline (36 versus 57mmHg; P = 0.002) and with supplemental oxygen admin-istration (47 versus 76 mmHg; P = 0.014). Immediatepostoperative tissue oxygen tension is also significantly lessin subcutaneous tissue of the upper arm (43 versus 54mmHg; P = 0.011) as well as near the incision (42 versus62 mmHg; P = 0.012) in obese patients.

Melling et al (2001) conducted a randomised study ofwound warming. 421 patients having clean (breast, vari-cose vein, or hernia) incisions closed after surgery. Patientsrandomly assigned to the non-warmed (standard) groupreceived the usual preoperative care, without any activetemperature control. Patients in the systemic warminggroup received the same standard preoperative care, plusthe addition of a minimum 30-minute preoperative warm-ing to the whole body using a forced-air, warming blanket.Patients assigned to the local warming group also receivedthe standard care and a minimum 30-minute preoperativewarming to just the planned wound area using a non-con-tact, radiant heat dressing. Both warming devices were leftin situ until just before surgery. A wound was classified asinfected if there had been a purulent discharge or a painfulerythema that lasted for 5 days and was treated withantibiotics within 6 weeks of surgery. Warming (localand/or systemic) was associated with significantly reducedpostoperative wound infection rate (Table 3.18).

Interestingly, local radiant heating has been shown toincrease subcutaneous oxygen tension for several hoursafter the heating has been discontinued (Ikeda et al, 1998)and wound oxygenation has also been identified as a sig-nificant factor in avoiding wound infection in patientsundergoing colorectal resection (Gottrup, 2004). Hopf et al(1997) identified the subcutaneous oxygen tension as a

Risk Management 93

TABLE 3.17 RANDOMIZED TRIAL OFDRAINS IN COLORECTAL SURGERY

Drainage Non-drainageMortality 18/573 (3%) 25/567(4%)Clinical anastomotic 11/522 (2%) 7/519 (1%)

dehiscenceRadiological 16/522 (3%) 19/519 (4%)

anastomotic dehiscence

Wound infection 29/573 (5%) 28/567 (5%)Re-intervention 24/542 (6%) 28/539 (5%)Extra abdominal 34/522 (7%) 32/519 (6%)

complications

After Jesus et al (2004).

stronger predictor of wound infection than the SENIC(Study on the Efficacy of Nosocomial Infection Control)score. A randomised study of 500 patients undergoing col-orectal operations (Greif et al, 2000) compared the effectsof two supplemental oxygen regimens (Table 3.19) on thedevelopment of postoperative wound infection—30% oxy-gen during and 2 hours after surgery versus 80% oxygenduring and 2 hours after surgery. The 80% oxygen sup-plemental group had a much lower incidence of woundinfection.

More recently, however, the routine use of perioperativehyperoxia in reducing surgical-site infection has beenchallenged. Pryor et al (2004) randomly assigned generalsurgical patients to receive either 80% oxygen (FiO2 of0.80) or 35% oxygen (FiO2 of 0.35) during surgery and forthe first 2 hours after surgery. The overall incidence of sur-gical-site infection was 18.1%: patients who developed sur-gical-site infection having a significantly longer period ofhospitalisation after surgery (mean [S.D.] 13.3 [9.9] ver-sus 6.0 [4.2] days; P < 0.001). In contrast to previous stud-ies, however, the incidence of infection was significantlyhigher in the group receiving FiO2 of 0.80 than in thegroup with FiO2 of 0.35 (25.0% versus 11.3%; P = 0.02).Indeed, in this study FiO2 was a significant predictor of sur-gical-site infection (P = 0.03) in multivariate regressionanalysis (Pryor et al, 2004). Aspects of this latter study,such as identifying wound infection from retrospectivechart review (Akca and Sessler, 2004; Hopf et al, 2004)and aspects of randomisation (Greif and Sessler, 2004)have attracted criticism. Other commentators (Urbach,2004) take the view that the possibility of an adverse effectof high FiO2 on surgical site infection in some surgical

patients means that, in clinical practice, oxygen shouldcontinue to be administered with the goals of maintainingadequate haemoglobin oxygen saturation and ensuringadequate oxygen transport, rather than achieving supra-normal levels of arterial oxygen tension.

Perioperative antibiotic prophylaxisThe term ‘prophylaxis’ should be confined to colorectalsurgery undertaken in the absence of established sepsis(Wittmann and Schein, 1996). Hence, antibiotic cover fordisease complicated by pericolic abscess, a fistula or activeperianal disease cannot be classified as prophylaxis and theterm ‘therapy’ should be used.

Topical antibioticsTopical antibiotics have been explored but administrationis rarely advised in colorectal procedures (Nash and Hugh,1967; Anderson et al, 1972; Evans and Pollock, 1973;Stone and Hester, 1973; Evans et al, 1974; Holder, 1976;Lord et al, 1977; Greenhall et al, 1979; Brumfitt andHamilton-Miller, 1980; Pitt et al, 1980; Pollock, 1981). Inintestinal surgery, topical cephradine was inferior to sys-temic antibiotic administration (Finch et al, 1979). Thecombination of broad-spectrum systemic antibiotic coverand topical agents conferred no benefit over intravenousadministration alone in colorectal surgery (Moesgaardet al, 1988; Raahave et al, 1989). A recent meta-analysisindicates that topical ampicillin versus no antibiotic pro-phylaxis in both clean contaminated wounds and con-taminated wounds significantly reduces surgical woundinfection rates (clean contaminated wounds OR = 0.084;95% CI 0.04–0.16; P < 0.0001; contaminated woundsOR = 0.262; 95% CI 0.14–0.51; P < 0.0001). However,topical ampicillin combined with systemic antibioticsoffers no reduction in surgical wound infection rates over systemic antibiotics alone (Charalambous et al, 2003).A recent Health Technology Assessment of antimicrobialprophylaxis in colorectal surgery could find no additionalbenefit in six trials that compared parenteral alone withparenteral plus topical wound antibiotic prophylaxis(Song and Glenny, 1998).

Intraincisional antibioticsAntibiotics may be administered by injection into the sub-cutaneous tissues and the rectus muscle immediately priorto laparotomy (Armstrong et al, 1982; Taylor et al, 1982;


TABLE 3.18 IMPACT OF WARMING ONWOUND INFECTIONS

Wound n infection rate

Local warming 138 5 (4%)Systemic warming 139 8 (6%)All warmed patients 277 13 (5%)Non-warmed 139 19 (14%)P 0.001

After Melling et al (2001).

TABLE 3.19 EFFECTS OF TWO SUPPLEMENTAL OXYGEN REGIMENSON THE DEVELOPMENT OF POSTOPERATIVE WOUND INFECTION

30% oxygen 80% oxygen (n = 250) (n = 250) P

Wound infection 28 (11.2%) 13 (5.2%) 0.01ASEPSIS score 5 ± 9 3 ± 7 0.01Solid food (days) 4.4 4.5 NSSkin staples out (days) 10.4 10.3 NSLength of stay (days) 11.9 12.2 NS

From Greif et al (2000).

NS, not significant.

Chalkiadakis et al, 1995). This method of delivery isassociated with more sustained serum levels of antibioticthan if the same agent is given intravenously. Clinical trialsindicate that this method of antibiotic cover may becomparable to systemic antibiotic cover in prevention ofwound sepsis in large-bowel surgery (Pollock et al, 1989).Infusion of kanamycin into the wound, allowing it to dwellfor 2 hours, was associated with a very low wound infec-tion rate in 400 morbidly obese patients undergoing opengastric bypass (Alexander and Rahn, 2004).

Antibiotic peritoneal lavageAntibiotic peritoneal lavage is controversial in colorectalpractice both for prophylaxis and treatment of intra-abdom-inal sepsis (Krukowski and Matheson, 1983; Krukowskiet al, 1984). Lavage with saline alone may be dangerousbecause microorganisms may be disseminated by peritoneallavage (Minervini et al, 1980b; Ambrose et al, 1982).Antibiotic lavage may be dangerous in faecal or purulentperitonitis because absorption is much more rapid and toxicserum levels have been reported (Ericsson et al, 1978).Renal failure and adhesive obstruction may occur if tetra-cycline lavage is used in acute peritonitis (Sandle andMandell, 1980; Phillips and Dudley, 1984).

Washington et al (1974) reported a significantly reducedrate of residual abdominal sepsis with erythromycin lavagecompared with saline alone in diffuse bacterial peritonitis.Williams and Champion (2004) demonstrated significantbacterial contamination of the peritoneal cavity adjacentto a laparoscopic entero-enterostomy but no clinical infec-tions after the use of parenteral antibiotics and peritonealantibiotic lavage.

Stephen and Loewenthal (1979) claimed that peritoneallavage with gentamicin, cephalothin and lincomycinimproved survival and reduced the risk of residual abscess.Others maintain that lavage with a broad-spectrum antibi-otic is effective (Rambo, 1972; Moukhtar and Romney,1980; Jennings et al, 1982). Tetracycline lavage is reportedby some to reduce sepsis in peritonitis from appendicitis andin colorectal surgery because of the very high peritonealconcentrations of tetracycline achieved in this way.However, these studies were not randomised (Steigbigelet al, 1968; Stewart and Matheson, 1978; Krukowski et al,1984). In a randomised trial of tetracycline lavage in con-taminated colorectal surgery, wound infection rates were

reduced but there was no influence on intra-abdominalsepsis despite a sustained reduction in the counts of aero-bic and anaerobic organisms in the peritoneal cavity(Silverman et al, 1986). However, more recently tetracy-cline has been withdrawn, and has been replaced in somecentres by other antibiotic peritoneal lavage solutions suchas cefotaxime (1 mg/mL) (Jansen et al, 2002).

As most antibiotics administered systemically achievehigh concentrations in peritoneal fluid, the intravenousroute is generally preferred for antibiotic administrationin the treatment of established intra-abdominal sepsis(Schiessel et al, 1984). Furthermore, Sauven et al (1986)reported that short-term antibiotic cover was superior totetracycline lavage. Similarly, Pearl and Rayburn (2004)concluded that minimal peritoneal lavage with non-antibiotic containing solutions is adequate in woundprophylaxis.

Oral antimicrobial agentsAntimicrobial prophylaxis in elective colorectal surgeryused to be exclusively by oral agents, such as neomycin orthe sulphonamides, which although poorly absorbed arethought to be capable of reducing the faecal flora. However,none was clinically effective because they had no influenceon the gut anaerobes (Poth and Knotts, 1942; Everett et al,1969; Washington et al, 1974; Varquish et al, 1978;Taylor et al, 1979).

Neomycin with metronidazole, however, caused a pro-found fall in the counts of aerobic and anaerobic flora inthe colon (Arabi et al, 1978), with a significant reductionin postoperative sepsis (Matheson et al, 1978). Neomycinand erythromycin base also reduced the counts of strepto-cocci, coliforms and Bacteroides spp. and clinical studiesindicated that these agents were capable of achieving a sig-nificant reduction in the rates of infection in elective col-orectal surgery (Nichols et al, 1971, 1972; Clarke et al,1977; Bartlett et al, 1978). Stenosing tumours of the largebowel did not adversely effect the reduction in faecalmicroflora achieved by oral antimicrobial agents (Figure3.7). A significant reduction in faecal flora and postopera-tive sepsis was observed using kanamycin and metronida-zole (Goldring et al, 1975; Keighley et al, 1979). However,metronidazole alone had no influence on the faecal floraunless there was severe diarrhoea (Lewis et al, 1977; Arabiet al, 1978).

Risk Management 95

Time (hours)

Con

cent

ratio

n (m

g/L

)

25

20

15

10

5

00 1 2 3 4 5 6 7 8 9

Cinc

AUClurg

Cclos

Figure 3.7 Profile of serumgentamicin concentration againsttime. C

inc, incision concentration; C

clos

closure concentration. After Zelenitskyet al (2002).

In a prospective multicentre randomised controlledstudy involving 11 centres, Clarke et al (1977) reportedthat oral neomycin and erythromycin reduced sepsis from43% to 9% but 407 patients were excluded, leaving only116 for eventual analysis. Brass et al (1978) found that thecombination of neomycin and erythromycin was inferiorto neomycin with metronidazole. Varquish et al (1978)showed that neomycin and erythromycin was no betterthan neomycin alone. If antibiotics are to be used to reducegut flora, ciprofloxacin may be more effective because it israpidly absorbed (Taylor and Lindsay, 1994; McArdle et al,1995).

When Weaver et al (1986) compared oral erythromy-cin and neomycin with systemic antibiotic cover the studyhad to be discontinued after the entry of only 60 patientsbecause of a 48% sepsis rate with the oral regimen. A sys-tematic review of RCTs of antimicrobial prophylaxis in col-orectal surgery concluded that trials that showed extrabenefit from the use of oral antibiotics used inadequate par-enteral regimens for comparison (Song and Glenny, 1998).Other serious disadvantages of oral agents are the promo-tion of antibiotic resistance (Hartley and Richmond, 1975;Keighley and Burdon, 1979; Lacey, 1980), superinfectionfrom yeasts or staphylococci and the risk of antibiotic-associated colitis (Keighley et al, 1979).

The combination of neomycin with erythromycin stillhas a considerable impact in parts of North America(Nichols et al, 1997; Nichols, 2001). The common prac-tice among colorectal surgeons in the USA uses both intra-luminal and parenteral prophylaxis, with the parenteralmedication administered immediately before the operation(Handelsman et al, 1993; Woods and Dellinger, 1998).A total of 471 of 808 board-certified colorectal surgeonsresponded to a survey of their current bowel preparationpractices before elective procedures. Most (86.5%) includeoral and parenteral antibiotics in their regimen; 11.5%used only parenteral antibiotics, 1.1% used only oralantibiotics and 0.9% used no antibiotics (Nichols et al, 1997). The American Society of Health-SystemPharmacists (ASHP) therapeutic guidelines includein their recommendations for colorectal surgery oralneomycin sulphate 1 g and erythromycin base 1 g givenafter bowel preparation is complete at 19, 18, and 9 hoursbefore surgery. The guidelines add that if the oral route iscontraindicated then a single 2-g dose of an intravenouscephalosporin with both aerobic and anaerobic activityshould be administered at induction of anaesthesia (ASHP,1999).

There is, however, some evidence that this practicemight change. Zmora et al (2003b) obtained 515 responses(81% colorectal accredited, average time in practice 13.7years) from 1295 questionnaires. Half of the respondentsstated that prophylactic oral antibiotics were essential, 41%felt their place was doubtful and 10% considered oral pro-phylaxis unnecessary. Despite these views, 75% of the sur-geons routinely utilised oral antibiotics (96% of them useda combination of two drugs), 11% used them selectivelyand only 13% omitted oral prophylaxis from their practice.Similarly, although the usefulness of intravenous antibioticswas questioned by 11% of the surgeons, 98% used themroutinely (Zmora et al, 2003b).

Systemic antimicrobial prophylaxisEarly studies compared antibiotic prophylaxis with noantibiotic cover at all and, almost without exception, theseindicated that some form of prophylaxis is better thanno cover at all (Stokes et al, 1974; Griffiths et al, 1976;Keighley and Crapp, 1976; Keighley et al, 1976; Downinget al, 1977; Willis et al, 1977; Hojer and Wetterfors, 1978;Eykyn et al, 1979). Two principles are important to followwhen selecting an antibiotic prophylactic regimen incolorectal surgery (Song and Glenny, 1998):

● The selected antibiotic(s) should be active against aerobicand anaerobic bacteria.

● The administration of antibiotics should be timed toensure that tissue concentration within the wound is highwhen bacterial contamination occurs.

Principles of systemic antibiotic prophylaxisTiming of antibiotic administrationAntibiotics are only effective when given immediately priorto the inoculation of bacteria into wounds (Burke, 1961).These principles were confirmed clinically by Stone and hiscolleagues (1976), who showed that if antibiotic adminis-tration was delayed for 1–4 hours after operation, the rateof sepsis was the same as if no antibiotic cover had beengiven at all. Systemic antibiotics should be administeredimmediately before the start of an operation, either in theanaesthetic room or in the theatre (Bates et al, 1989).

Zelenitsky et al (2002) studied wound infection rates incolorectal surgical patients receiving gentamicin prophyl-axis. The gentamicin concentration at the time of surgicalclosure was one of the strongest independent risk factorsfor infection (P = 0.02), along with the presence of dia-betes mellitus (P = 0.02), stoma (P = 0.04), and advancedage (P = 0.05). Gentamicin concentrations at closure of< 0.5 mg/L were associated with an infection rate of 80%(representing 8/10 patients with concentrations below thatlevel; P = 0.003). ROC curve analysis identified a criticalclosure concentration of 1.6 mg/L for effective surgicalprophylaxis (P = 0.002; sensitivity, 70.8%; specificity,65.9%) (see Figure 3.7).

Timing of prophylaxis still requires emphasis. Bratzleret al (2005) carried out a retrospective cohort study of34 133 Medicare inpatients undergoing a range of proce-dures, including colorectal resection, to determine thetiming of antibiotic prophylaxis in relation to the timingof the incision. In this large study only 55.7% (95% CI54.8–56.6%) of patients received their antimicrobial pro-phylaxis within 1 hour before incision. Galandiuk et al(2004) found that hospital participation in a quality net-work improved the rate of timely antibiotic administra-tion in patients undergoing both colon and rectalresections. In the first 30 months of the study period forcolon resection, 66% of patients (63/96) received a sys-temic antibiotic preoperatively compared with 98%(117/119) in the second half of the study period (P <0.0001). Similarly, for rectal resections, in the first halfof the study period, 79% of patients (34/43) receivedantibiotic preoperatively compared with 100% of patientsin the last 30-plus months of the study period (P <0.0001).


Route of administration: oral or systemic?A few studies have compared oral against systemic antimi-crobial prophylaxis. In three, oral administration wasinferior to systemic antibiotic cover (Keighley et al, 1979;Weaver et al, 1986; Lau et al, 1988), whereas two studiesshowed no difference (Aeberhard et al, 1979; Beggs et al,1982). The combination of oral and systemic antibioticcover was shown to be superior to intravenous adminis-tration alone in three studies (Kaiser et al, 1983; Playforthet al, 1988; Taylor and Lindsay, 1994), equivalent in onestudy (Lau et al, 1988) and inferior in another (Coppa andEng, 1988).

Espin-Basany et al (2005) compared 300 electivepatients undergoing colorectal resection randomised to oneof the following three groups: group A received three dosesof oral antibiotic at the time of mechanical colon cleans-ing (1 g neomycin and 1 g metronidazole at 3.00 p.m.,7.00 p.m. and 11.00 p.m.); group B received one dose oforal antibiotic (1 g neomycin and 1 g metronidazole at3.00 p.m.) and group C received no oral antibiotics. Notonly did oral antibiotics not confer any advantage in reduc-ing wound sepsis (Table 3.20), but patient tolerance to oralantibiotics, reflected as gastrointestinal symptoms at thetime of preoperative preparation for surgery (i.e. nausea,vomiting), was significantly more common in patients withcombined treatment (group A) than in those who did notreceive oral antibiotics or received only one dose.

Influence on faecal floraIn view of the dangers of disturbing the normal faecalflora, it is appropriate to consider the influence of intra-venous antibiotic administration on colonic microflora.Jonkers et al (2002) studied cardiac surgery patients whoreceived cefazolin as antibiotic prophylaxis (2 g intra-venously just before surgery and then 1 g intravenouslyevery 6 hours for 18 hours). Patients who were receivingtherapeutic antibiotics during hospitalisation wereexcluded. Discharged patients had received 24-hour cefa-zolin prophylaxis and had a mean hospital stay of 10 ± 5days. The prevalence of resistance of Escherichia coli toamoxicillin (P < 0.05), cefazolin (P < 0.05) and oxytetra-cycline was higher for patients at discharge (41%, 12% and35%) than for patients at admission (28%, 2% and 27%).Intravenous doxycycline and many of the third-generation

cephalosporins suppress faecal microflora with the emer-gence of Clostridium difficile (Ambrose et al, 1985), whereastinidazole, metronidazole and most of the penicillinshave little, if any, influence (Heimdahl and Nord, 1979;Heimdahl et al, 1982; Kager et al, 1985).

Prophylactic regimensThe antibiotics chosen for prophylaxis should provide ade-quate serum concentrations for the duration of the opera-tion. Some cephalosporins, penicillins and aminoglycosideshave extremely short half-lives. Therefore, for complexcolorectal procedures involving excessive blood loss or pro-longed operation, repeated intraoperative antibiotic admin-istration may be indicated (Burdon et al, 1985).

With the exception of a study with four major variablesand small numbers (McArdle et al, 1995) most now indi-cate that, provided antibiotics with an adequate half-lifeare used for prophylaxis, single-dose cover is as effective asprolonged antibiotic cover for 24 hours or even several days(Higgens et al, 1980; Giercksky et al, 1982; Goranssonet al, 1984; Dipiro et al, 1986; Juul et al, 1987; Jensen et al,1990; Rowe-Jones et al, 1990; Wittmann and Schein,1996). Agents such as ceftriaxone, with a long serum half-life, have been particularly effective in large-bowel surgery(Shepherd et al, 1986; Weaver et al, 1986; Morris, 1993;Matikainen and Hiltunen, 1993). Song and Glenny (1998)in a health technology assessment, examined seventeenrandomised trials comparing a single-dose regimen with amultiple-dose regimen (one or two doses) using the sameantibiotic or combinations of antibiotics. None of these tri-als found a significant difference in postoperative surgicalwound infection between single dose and multiple doseregimens.

Many studies have examined single and combinedantibiotic agent efficacy for prophylaxis in colorectal sur-gery (Morris et al, 1984; Cunliffe et al, 1985; NorwegianStudy Group, 1985; Roland et al, 1986; Bergman andSolhaug, 1987). So far, single-agent, broad-spectrumantibiotic cover does not seem to be sufficiently reliableto be advised in colorectal surgery (Hares et al, 1981a;de la Hunt and Karran, 1986; McCulloch et al, 1986; Tudoret al, 1988; Walker et al, 1988; Hall et al, 1989;Kingston et al, 1989; Taylor and Lindsay, 1994). A spe-cific anaerobicide alone is inadequate for prophylaxis

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TABLE 3.20 COMPARISON OF POSTOPERATIVE COMPLICATIONSAMONG TREATMENT GROUPS

Group A % Group B % Group C % P valueWound infection 7 8 6 0.858Suture dehiscence 2 2 3Postoperative ileus 7 13 10 0.368Urinary tract infection 4 4 3Intra-abdominal abscess 4 3 4Pneumonia 0 1 2

After Espin-Basany et al (2005).

Group A: three doses of oral antibiotic at the time of mechanical colon cleansing (1 g of neomycin

and 1 g of metronidazole at 3.00 p.m., 7.00 p.m. and 11.00 p.m.); group B: one dose of oral antibiotic

(1 g of neomycin and 1 g of metronidazole at 3:00 p.m.); group C: no oral antibiotics.

(Cunliffe et al, 1985; Roland et al, 1986; Khubchandaniet al, 1989). Cephalosporins or penicillins in combina-tion with a β-lactamase inhibitor are less effective thantheir use in combination with metronidazole becausethey are not sufficiently active in vivo against faecalanaerobes (Condon et al, 1979; Hoffmann et al, 1981;Kager et al, 1981; Ivarsson et al, 1982; Kaiser et al,1983; Peck et al, 1984; Baker et al, 1985; Drumm andDonovan, 1985; de la Hunt and Karran, 1986; Hall et al,1989; Hakansson et al, 1993). Song and Glenny (1998)analysed a total of 147 RCTs exploring antibiotic pro-phylaxis in colorectal surgery. They concluded that theestimates of efficacy of many of the different regimenswere very similar. As a result it was not possible to iden-tify a ‘best one’. However, they found that there was noconvincing evidence that new generation cephalosporinsare more efficacious than first generation cephalosporinsin preventing surgical wound infection in colorectalsurgery.

Platell and Hall (2001) note that, given the results ofnumerous previous trials, it would appear that clinicaltrials of antibiotic wound prophylaxis in colorectal surgeryare being performed with the commercial intent of estab-lishing equivalence. It is therefore pertinent that Woodfieldet al (2005) carried out a prospective randomised com-parison of the pharmacoeconomic effectiveness of ceftri-axone and cefotaxime prophylaxis in abdominal surgery,the aim being to use the cost of infection as a direct meas-urement of the severity of infection. In this study, 1013patients admitted into a general surgical unit for bothacute and arranged abdominal surgery were studied overa 3-year period. The major endpoint was superficial or deepsurgical site infection. Hospital costs associated with woundinfection along with outpatient costs (outpatient clinics,accident and emergency care, the use of community nurs-ing service, loss of wages, the use of primary care andprivate health-care services, insurance expenses, and sup-plements to income by social welfare) were ascertained.

The frequency (Woodfield et al, 2005) of wound infec-tion for appendicectomies when additional metronidazolewas not administered was greater with cefotaxime (ceftri-

axone 6%, cefotaxime 18%, P < 0.05) but the cost of infec-tion was the same (average cost ceftriaxone $994 ± s.d.$1101, cefotaxime $878 ± $1318). For all other proce-dures, the frequency of wound infection was similar (cef-triaxone 8%, cefotaxime 10%) but the cost was less withceftriaxone (ceftriaxone $887 ± $1743, cefotaxime $2995± $6592; P < 0.05). Ceftriaxone decreased the frequencybut not the cost of chest and urinary infection (fre-quency ceftriaxone 6%, cefotaxime 11%; P < 0.02; cost cef-triaxone $1273 ± 2338, cefotaxime $1615 ± 4083).Ceftriaxone decreased either the frequency or the cost ofdifferent postoperative infections (Table 3.21). In thefuture, the cost of infection after antibiotic prophylaxis mayboth increase the discriminatory power of trials comparingantibiotic effectiveness and provide a significant factor inprophylactic regimen choice.

Methicillin-resistant Staphylococcus aureusAn unfortunate feature of all hospital medicine, includingcolorectal surgical practice, is the increasing prevalence ofmethicillin-resistant Staph. aureus (MRSA) (Figure 3.8),which is now considered to be undergoing an epidemicincrease, hence the designation EMRSA for epidemic MRSAstrains (Leaper, 2004).

A retrospective cohort study at the Detroit ReceivingHospital, between 1999 and 2001, of patients with Staph.aureus bacteraemia compared outcomes associated withMRSA isolates and methicillin-susceptible Staph. aureus(MSSA; Lodise and McKinnon, 2005). Controlling forconfounding variables, patients with MRSA had a 1.5-foldlonger length of stay (19.1 versus 14.2 days; P = 0.005)and a 2-fold increased cost of hospitalisation ($21 577 ver-sus $11 668; P = 0.001) compared with MSSA. In addi-tion, patients with MRSA were at increased risk ofinfection-related death (Table 3.22).

Isolated strains of MRSA are numbered sequentially inthe UK, where three have dominated: EMRSA-1, which wasprevalent in the Thames regions in the 1980s and proba-bly originating in Australia, and EMRSA-15 and EMRSA-16, which are currently predominant in the UK and areresponsible for outbreaks elsewhere (Duckworth, 2003).


TABLE 3.21 COST OF SUPERFICIAL AND DEEP SURGICAL SITEINFECTION

Ceftriaxone Cefotaxime P value

All cases except appendectomy without metronidazoleNumber of patients 379 358Number with infection 31 (8%) 36 (10%) NSMean cost $ (± SD) 887 (± 1743) 2995 (± 6592) < 0.05*

Median cost $ (range) 170 (19–6767) 824 (21–31 914)

Appendectomy without metronidazolezoleNumber of patients 83 100Number with infection 5 (6%) 18 (18%) < 0.05Mean cost $ (± SD) 994 (± 1101) 878 (± 1368) NSMedian cost $ (range) 614 (66–2860) 330 (0–4557)

After Woodfield et al (2005).

Initial UK guidelines to reduce MRSA rates in UK hospitalsby a ‘search and destroy’ policy were watered down by poorsupport from senior management, lack of isolation facili-ties, high occupancy rates of beds and understaffing(Duckworth, 2003). There is evidence that some of thegovernment’s policies conflict with the prevention and con-trol of infections. Seven out of 10 Hospital Trusts still havebed occupancy rates levels that are higher than the 82%target set by the Department of Health for 2003–4(Kmietowicz, 2005).

The UK now has some of the highest rates of MRSAinfection in Europe (Duckworth, 2003). By contrast, theprevalence of MRSA in the Netherlands is among the low-est in the world: the Netherlands prevalence of MRSAamong clinical Staph. aureus isolates < 1%. This success isbased on a ‘search and destroy policy’ (Wertheim et al,2004). All patients from countries outside the Netherlandsand contacts of MRSA patients are strictly isolated at hos-pital admission until screening cultures for MRSA provenegative (‘search’). In case of MRSA carriage, individualsare kept in isolation and treated to eradicate MRSA

(‘destroy’) (Wertheim et al, 2004). Although the evidencebase for formulating MRSA reduction programmes is com-plex, isolation of MRSA-positive individuals would appearto play a central role (Cooper et al, 2004; Bissett, 2005).

THROMBOEMBOLISM PROPHYLAXISPatients at riskAlthough it is unlikely that minor anorectal surgery posesa significant risk of venous thromboembolism, patientsundergoing major abdominal colorectal procedures areat high risk of developing postoperative venous throm-boembolism (The Standards Task Force of the AmericanSociety of Colon and Rectal Surgeons, 2000). Estimatesfrom control groups of randomised prophylaxis trials showthat > 30% of colorectal surgical patients develop post-operative deep venous thrombosis (DVT) compared withapproximately 20% of all general surgery patients (McLeodet al, 2001). Tongren (1983) found fatal pulmonaryembolism (PE) in 3.1% of colorectal surgery patientsand in 0.8% of those having other abdominal surgicalprocedures.

Risk factors for venous thromboembolism include ageover 40 years, extended immobility or paralysis, priorepisodes of venous thromboembolism, malignancy, majorsurgery, obesity, congestive heart failure, myocardial infarc-tion, stroke, pelvic and long bone fractures, presence of anindwelling femoral catheter, inflammatory bowel disease,nephrotic syndrome and oestrogen use (Table 3.23) (Rosenand Clagett, 1999). Among the hypercoagulable states thatcontribute to the risk for venous thromboembolism areactivated protein C resistance (factor V R506Q [Leiden]mutation), prothrombin 20210A, antithrombin III defi-ciency, and protein C and protein S deficiency, as well asantiphospholipid antibodies, dysfibrinogenaemias, hyper-homocystinaemia, disorders of plasminogen and myelo-proliferative disorders (Rosen and Clagett, 1999).

Because of the perceived risk of venous thromboem-bolism and the opportunity to reduce preventable postop-erative deaths, there continues to be considerable interest

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TABLE 3.23 RISK FACTORS FORTHROMBOEMBOLISM

Major abdominal or pelvic surgeryAge > 40 yearsPrevious thromboembolic eventHereditary hypercoagulable stateMalignancyMorbid obesityInflammatory bowel diseaseStroke (with paralysis)Prolonged immobilizationHeparin-induced thrombocytopeniaCongestive heart failureAcute myocardial infarctionOral contraceptivesTamoxifenVenous stasis

From Practice Parameters (2000).

44%

34%

42%

49%

35%

45%

46%

41%43%

Figure 3.8 Methicillin-resistant isolates in Staphylococcusaureus bacteraemia reports from England and Wales. Fromhttp://www.hpa.org.uk/cdr/PDFfiles/2001/cdr0701.pdf

TABLE 3.22 UNIVARIATE ANALYSIS OFTHE IMPACT OF MRSA ON OUTCOMES

MRSA MSSA Outcome (n = 170) (n = 183) P valueInfection-related 52 (30.6 %) 28 (15.3%) 0.001

mortalityLOS-SAB (days) 20.1 13.7 < 0.001Cost-SAB ($) 22 735 11 205 < 0.001

After Lodise and McKinnon (2005).

LOS, length of stay; SAB, Staphylococcus aureus bacteraemia.

in reducing postoperative mortality from this cause. Usingrisk factors, prophylaxis against postoperative venousthromboembolism should be tailored according to thepatient’s level of risk (Caprini et al, 1991). Two methods ofprophylaxis are available either separately or in combina-tion: mechanical techniques (pneumatic compressionand/or graded compression stockings) or anticoagulantprophylaxis.

Mechanical prophylaxisNicolaides et al (2001) reviewed the evidence for the effi-cacy of mechanical prophylaxis in patients undergoinggeneral surgical and urological procedures. When DVT wasassessed, by phlebography or fibrinogen uptake, a reducedincidence of DVT was seen for both intermittent compres-sion and the use of graduated elastic compression stock-ings. This review data from 13 studies of intermittentpneumatic compression showed DVT formation in 7.7% of776 patients compared with 24% of 835 control patients.A pooled comparison for the prophylactic use of graduatedcompression stockings demonstrated a DVT rate of 11% in463 patients subjected to the intervention compared with29% of the 446 control patients (Nicolaides et al, 2001).

In a Cochrane systematic review, Amaragiri and Lees(2000) considered the outcomes of seven RCTs in whichgraduated compression stockings were the sole form of pro-phylaxis in a treatment group of 536 patients. The use ofcompression stockings was associated with a DVT rate of15% (assessed by I125 uptake test) compared with 29% in the491 control patients (Peto’s OR 0.36; 95% CI 0.26–0.49)with an overall effect of favouring treatment with graduatedcompression stockings (P < 0.00001). The authors also con-cluded that graduated compression stocking prophylaxiswas even more effective when combined with another pro-phylactic technique (Amaragiri and Lees, 2000).

The optimal length of stocking required to prevent DVTwas the subject of a randomised study by Howard et al(2004). This study recruited patients from a variety ofsurgical specialties: breast and oncology (73 patients), ENT(13), gastrointestinal (122), neurosurgery (34), orthopaedic(62), urology (58) and vascular venous surgery (14). Theefficacy of stocking length in reducing DVT formation wasassessed against a background of low-molecular-weightheparin (LMWH) thromboprophylaxis. The authors foundthat the Medi Thrombexin® climax™ thigh-length stock-ings were significantly better at preventing postoperativeDVT than the knee-length stockings (2 versus 11; OR 0.18;95% CI 0.04–0782; P = 0.026) (Howard et al, 2004).

An alternative method of mechanical prophylaxis forpostoperative DVT/PE is the use of intermittent pneumaticcompression of the legs. A sequential compression deviceconsists of a microprocessor allowing pressurised air (e.g.45 mmHg) into segmental compartments secured aroundthe leg for a fixed period of time (e.g. 11 seconds) (Augusteet al, 2004). Sequential devices produce a wave-likemilking effect to evacuate the leg veins. This compressionmay exert its prophylactic effect on thromboembolism,partly by preventing venous stasis and partly from enhanc-ing fibrinolysis. In one study, intermittent pneumaticcompression applied for 120 minutes to 21 male, non-smoking volunteers ranging in age from 19 to 47 years was

associated with a significant increase in global fibrinolyticpotential (Giddings et al, 2004).

Ramirez et al (2003) audited the incidence of DVTand/or PE in 1281 patients with colon cancer, rectal can-cer or inflammatory bowel disease. All underwent majorabdominal or transabdominal pelvic surgery with theirthromboembolism prophylaxis being exclusively deliveredusing sequential compression devices. Ten episodes ofvenous thromboembolism were identified, for an incidenceof 0.78%. These included seven cases of thrombophlebitis(incidence of 0.55%) and three cases of PE (incidence of0.23%). Among the 944 patients who had surgery for col-orectal cancer, the incidence of venous thromboembolism(VTE) was 0.53%. Among the 337 patients who had majorsurgery for inflammatory bowel disease, the incidence ofVTE was 1.48% (Ramirez et al, 2003). The authors con-cluded that VTE prophylaxis employing sequential com-pression devices alone does not result in a higher incidenceof VTE than the incidence reported for modern colorectalpractice. In addition, they suggested (Ramirez et al, 2003)that because sequential compression devices are not asso-ciated with bleeding complications, advocating the use ofthese devices in the highest-risk patients may increase sur-geons’ compliance for VTE prophylaxis in those patients.

Heparin prophylaxisHeparin is the dominant form of pharmacological prophyl-axis against VTE in colorectal practice. About one-third ofan administered dose of heparin binds to antithrombin (AT)and this fraction is responsible for most of its anticoagulanteffect (Hirsh et al, 2001). The heparin–AT complex inacti-vates a number of coagulation enzymes, including throm-bin factor (IIa) and factors Xa, IXa, XIa and XIIa. Of these,thrombin and factor Xa are most responsive to inhibitionand human thrombin is about 10-fold more sensitive toinhibition by the heparin–AT complex than factor Xa (Hirshet al, 2001) (Table 3.24).

To inhibit thrombin, heparin must bind to both thecoagulation enzyme and AT, but binding to the enzyme isless important for the inhibition of activated factor X (fac-tor Xa). Molecules of heparin containing < 18 saccharidesdo not bind simultaneously to thrombin and AT and aretherefore unable to catalyse thrombin inhibition. By con-trast, very small heparin fragments containing the high-affinity pentasaccharide sequence catalyse inhibition offactor Xa by AT. By inactivating thrombin, heparin not onlyprevents fibrin formation but also inhibits thrombin-inducedactivation of factor V and factor VIII. Unfractionatedheparin (UFH) and LMWH also induce secretion of the tis-sue factor pathway inhibitor by vascular endothelial cells.This reduces procoagulant activity of tissue factor VIIacomplex and could contribute to the antithrombotic actionof heparin and LMWH (Hirsh et al, 2001).

The activated partial thromboplastin time (APTT) activ-ity of heparin mainly reflects its antifactor IIa activity.LMWH fractions prepared from standard commercial-grade heparin have progressively less effect on the APTT,as they were reduced in molecular size, while still inhibit-ing activated factor X (factor Xa) (Hirsh et al, 2001). Thereduced antifactor IIa activity relative to antifactor Xaactivity of LMWH, combined with a better benefit-to-risk


ratio observed in animal experiments, have stimulatedinterest in its clinical use (Hirsh et al, 2001). However, it isthe pharmacokinetic differences between LMWH and UFHthat are of most clinical importance (Hirsh et al, 2001)(Table 3.25).

LMWHs produce a more predictable anticoagulantresponse than unfractionated heparin, reflecting their bet-ter bioavailability, longer half-life and dose-independentclearance (Weitz, 1997). Thus, when LMWHs are givensubcutaneously in low doses, the recovery of antifactor Xaactivity approaches 100%, compared with about 30% withunfractionated heparin. The plasma half-life of LMWHs istwo to four times longer than that of unfractionatedheparin, ranging from 2 to 4 hours after intravenous injec-tion and from 3 to 6 hours after subcutaneous injection.The inhibitory activity of low-molecular-weight heparinsagainst factor Xa persists longer than their inhibitory activ-ity against thrombin, reflecting the more rapid clearanceof longer heparin chains (Weitz, 1997).

In a Canadian multicentre, double-blind trial (McLeodet al, 2001), patients undergoing resection of part or all ofthe colon or rectum were randomised to receive, by sub-cutaneous injection, either calcium heparin 5000 unitsevery 8 hours (low dose unfractionated heparin; LDH) orenoxaparin (LMWH) 40 mg once daily (plus two additionalsaline injections). DVT was assessed by routine bilateral

contrast venography performed between postoperative days5 and 9, or earlier if clinically suspected. The venousthromboembolism rate was the same in both groups:44/468 or 9.4% (95% CI of the difference, 0 ± 3.7%). Ofthese, five were symptomatic (three in the LDH group, twoin the LMWH group). The rate of proximal DVT was 2.6%in the LDH group and 2.8% in the LMWH group. Noinstances of isolated iliac vein thrombosis were identifiedby venography or ultrasonography; only one enoxaparinpatient had a symptomatic, non-fatal PE. No deaths wereattributable to thromboembolism. The total bleeding eventrate was significantly lower in the LDH group than in theLMWH group (6.2% vs. 10.1%, P = 0.003), primarilybecause of an excess of minor bleeding episodes in theLMWH patients (P = 0.03). The rate of major bleedingevents was also increased, but not significantly (1.5% vs.2.7%, 95% CI difference −0.4 to 2.8%; P = 0.136). Overall,only three patients required reoperation for bleeding; noneof the patients died of a bleeding complication (McLeodet al, 2001).

Data from the Canadian Colorectal Trial (Etchells et al,1999) was used in an economic analysis of low-doseheparin versus the LMWH enoxaparin for prevention ofvenous thromboembolism after colorectal surgery. In thisanalysis the relative risk of DVT and PE for enoxaparincompared with low-dose heparin was 1.0 (95% CI

Risk Management 101

TABLE 3.25 COMPARISON OF LOW-MOLECULAR-WEIGHT HEPARIN PREPARATIONS

Mean molecular Anti Xa:Anti IIa Preparation Method of preparation weight ratioArdeparin Peroxidative depolymerisation 6000 1.9Dalteparin Nitrous acid depolymerisation 6000 2.7Enoxaparin Benzylation and alkaline depolymerisation 4200 3.8Nadroparin Nitrous acid depolymerisation 4500 3.6Reviparin Nitrous acid depolymerisation, 4000 3.5

chromatographic purificationTinzaparin Heparinase digestion 4500 1.9

From Weitz (1997), copyright © Massachusetts Medical Society. All rights reserved.

TABLE 3.24 ANTIHAEMOSTATIC EFFECTS OF HEPARIN

Effects CommentsBinds to AT-III and catalyses Major mechanism for anticoagulant effect,

inactivation of factors IIa, produced by only one third of heparin molecules Xa, IXa, and XIIa (those containing the unique AT-III-binding

pentasaccharide)Binds to heparin cofactor II Anticoagulant effect requires high concentrations

and catalyses inactivation of heparin and occurs to the same degree of factor IIa whether or not the heparin has high or low

affinity for AT-IIIBinds to platelets Inhibits platelet function and contributes to the

hemorrhagic effects of heparin. High-molecular-weight fractions have greater effect than low-molecular-weight fractions

From Hirsh et al (2001).

0.7–1.5) and the relative risk of major bleeding was 1.8(95% CI 0.8–3.9). With the use of these data in the base-line analysis, a strategy of enoxaparin prophylaxis wasassociated with equal numbers of symptomatic DVTs andPEs, and an excess of 12 major bleeding episodes forevery 1000 patients treated, with an additional cost of$86 050 (Canadian data) or $145 667 (US data). Theinvestigators (Etchells et al, 1999) concluded thatalthough heparin and enoxaparin are equally effective,low-dose heparin is a more economically attractivechoice for thromboembolism prophylaxis after colorectalsurgery.

In the Cochrane Systematic Review (Wille-Jørgensenet al, 2004), the efficacy of heparin and mechanical meth-ods in thromboprophylaxis of patients undergoing col-orectal surgery was considered. This review identified 558studies, of which 477 were excluded. A total of 19 studiesentered the review, only three of which focused exclusivelyon colorectal patients. The findings were as follows(WilleJørgensen et al, 2004):

● Heparins versus no treatment: any kind of heparincompared to no treatment or placebo (11 studies).Heparin is better in preventing DVT and/or PE, with aPeto odds ratio at 0.32 (95% CI 0.20–0.53).

● Unfractionated heparin versus LMWH (four studies): thetwo treatments were found equally effective in preventingDVT and/or PE, with a Peto odds ratio 1.01 (95% CI0.67–1.52).

● Mechanical methods (two studies): the combination ofgraded compression stockings and LDH is better than LDHalone in preventing DVT and/or PE, with a Peto odds ratioat 4.17 (95% CI 1.37–12.70).

The authors of the systematic review (Borly et al, 2005)concluded that the optimal thromboprophylaxis incolorectal surgery is the combination of graduatedcompression stockings and LDH or LMWH.

A similar review (Bergqvist, 2004) identified a total of16 comparative studies examining the role of heparin inpreventing thromboembolism after abdominal surgery(Table 3.26). These showed that LMWH is as effective asUFH in reducing VTE after abdominal surgery and, at

appropriate doses, can reduce bleeding complications. Invery high-risk patients, a higher dose of LMWH may offerincreased efficacy without increasing bleeding risk. In addi-tion, Bergqvist (2005) concluded that extending the stan-dard 7–10-day period of prophylaxis may benefit certainhigh-risk groups.

Applying venous thromboembolismprophylaxisA major anxiety in VTE prophylaxis is that, despite insti-tutional protocols, individual patients may be omitted fromthese measures. Tooher et al (2005) identified six studiesthat relied on the passive dissemination of guidelines (viainternational or local publication) to change VTE prophyl-axis practice. Adherence to guidelines and the provision ofadequate prophylaxis was poor in these studies, with nomore than 50% of patients receiving appropriate prophyl-axis, despite dissemination of the guideline. By contrast,the most effective strategies incorporated a system forreminding clinicians to assess patients for venous throm-boembolism risk, either electronic decision-support systemsor paper-based reminders, and used audit and feedback tofacilitate the iterative refinement of the intervention(Tooher et al, 2005).

Mosen et al (2004) addressed the value of a computerreminder system in improving the rate of VTE prophyl-axis. A comparison was made of the rate of symptomaticDVT/PE in patient groups: one group (2077 surgicalpatients) receiving prophylaxis before the computerisedreminder system and a second group (2093 surgicalpatients) whose venous prophylaxis was subjected to acomputerised reminder. The overall prophylaxis rateincreased from 89.9% before implementation of thecomputerised reminder system to 95.0% after implemen-tation (P < 0.0001). The combined 90-day rate of symp-tomatic DVT, PE and death attributable to PE remainedthe same (preintervention 1.0%; postintervention 1.2%;odds ratio 1.21; 95% CI 0.67–2.20). However, of the 46venous thrombembolic complications, 87% (40/46)occurred despite the delivery of American College of ChestPhysicians recommended measures to prevent VTE (Mosenet al, 2004).


TABLE 3.26 SUMMARY OF COMPARATIVE CLINICAL TRIALS OF LOW-MOLECULAR-WEIGHTHEPARIN (LMWH) PROPHYLAXIS IN COLORECTAL SURGERY

Trial design No. of LMWH Once-daily patients versus dose of

comparator LMWH Safety EfficacyDouble-blind 936 Enoxaparin 40 mg s.c. Major bleeding: 2.7 versus VTE: 9.4% in both groups

randomized versus UFH 1.5% (P = 0.136) Proximal DVT: 2.8 multicentre versus 2.6%

Randomized 320 Enoxaparin 40 mg s.c. Bleeding complications: DVT: 0 versus 3% controlled versus control* 6.7 versus (P = 0.045)

1.8% (P = 0.037)

From Bergqvist (2004).

*Control group had no prophylaxis.

DVT, deep vein thrombosis; s.c., subcutaneous; UFH, unfractionated low-dose heparin; VTE, venous thromboembolism.

LMWH versus comparator

VTE prophylaxis protocols should be included in surgi-cal unit and ward guidelines, clinical pathways and resi-dent medical officer manuals. Regular audits should beundertaken of the extent and quality of VTE prophylacticmeasures. There should be documentation in the casenotes of the VTE risk assessment for each patient and anyprophylactic measures that are used, mechanical (gradu-ated compression stockings, intermittent pneumaticcompression) as well as pharmacological prophylaxis withunfractionated heparin or LMWH (Fletcher, 2002).

After discharge home, the surgical patient can still bevulnerable to VTE (Kearon, 2003). In orthopaedic surgery,particularly in patients undergoing hip surgery, there is agrowing interest in using extended anticoagulationbeyond that traditionally given in the postoperative periodusing LMWH, oral anticoagulants, or newer agents suchas fondaparinux sodium. Most studies show a benefit toextending anticoagulation without a considerable increasein major bleeding (Blanchard and Ansell, 2005). Hull et al(2001) examined studies of out of hospital VTE prophyl-axis with LMWH in patients undergoing elective hip sur-gery. Systematic review of six studies showed that,compared with placebo, extended out-of-hospital LMWHprophylaxis decreased the frequency of all episodes of deepvenous thrombosis [placebo rate 150/666 patients(22.5%); relative risk 0.41; 95% CI 0.32–0.54; P <0.001], proximal venous thrombosis [placebo rate 76/678patients (11.2%); relative risk 0.31; 95% CI 0.20–0.47; P <0.001] and symptomatic venous thromboembolism[placebo rate 36/862 patients (4.2%); relative risk 0.36;95% CI 0.20–0.67; P = 0.001]. Major bleeding was rare,occurring in only one patient in the placebo group (Hullet al, 2001).

Bergqvist et al (2002) examined the role of extended out-of-hospital LMWH prophylaxis in patients undergoing open,elective, curative surgery for a malignant tumour of thegastrointestinal tract (other than the oesophagus),genitourinary tract, or female reproductive organs. Allpatients received 40 mg enoxaparin once daily, with the firstdose given 10–14 hours preoperatively, for 6–10 days. Afterthis open-treatment period, the patients were randomlyassigned to receive 40 mg subcutaneous enoxaparin orplacebo once daily for 19–21 days. The mean duration ofdouble-blind therapy was 19.5 days in the placebo groupand 19.3 days in the enoxaparin group. During the double-blind period (Bergqvist et al, 2002), the overall incidence ofvenous thromboembolism was 8.4% (28/332). In the groupgiven 1 week of prophylaxis (placebo group), the incidencewas 12.0% (20/167); in the group given 4 weeks of pro-phylaxis, it was 4.8% (8/165) (P = 0.02). This correspondsto a reduction in risk of 60% (95% CI 10–82). Proximaldeep vein thrombosis was identified in three patients in theplacebo group and one in the enoxaparin group. Similarresults have been described in colorectal cancer patients.Rasmussen (2003) investigated 117 patents having surgeryfor malignant disease (colorectal cancer resection in thelarge majority) 63 of whom had no further thrombopro-phylaxis on discharge and 53 being given 4 weeks of outof hospital prophylaxis with dalteparin 5000 IU daily.Prolonged thromboprophylaxis with daltaparin in this can-cer population reduced the incidence of all DVT from 15.9%

to 5.6% and reduced the incidence of proximal DVT from15.9% to 0% (P < 0.005) (Rasmussen, 2003).

In general surgery, LMWHs are relied on more andmore for prophylaxis and initial anticoagulant treatmentof DVT, because of their multiple advantages in efficacy,safety and convenience in handling (Gutt et al, 2005).Newer anticoagulant molecules such as fondaparinux andximelagatran seem to have similar efficacy to LMWH in thetreatment of VTE, but they have a 2-fold increased efficacyin its prophylaxis (Gutt et al, 2005). The new anticoagulantscan be classified as follows (Hoppener and Buller, 2005).

Tissue factor/factor VIIa inhibitorsThe initiation of thrombus formation occurs when tissuefactor, exposed within a damaged blood vessel, rapidlycomplexes with factor VIIa. A recombinant nematodeanticoagulant protein C2 (r-NAPc2), based on a substancepresent in the saliva of the hookworm, is a potentinhibitor of the tissue factor/factor VIIa complex.Subcutaneous injection on alternate days is effective inthe prevention of venous thromboembolism after totalknee replacement.

Factor Xa inhibitorsIndirect inhibitors are synthetic analogues of the five keysugars (pentasaccharides) present in heparin that specifi-cally bind to the natural anticoagulant anti-thrombin, andsubsequently block factor Xa. Two pentasaccharides, bothadministered subcutaneously, are now available: fonda-parinux has a half-life of 15–20 hours (which makes itsuitable for once-a-day administration) and idraparinuxhas a half-life of about 130 hours (and so can be adminis-tered once a week).

The PEGASUS study (Bauersachs, 2005) compared theefficacy and safety of fondaparinux with the LNWH dal-teparin in the prevention of VTE in 2048 patients at highVTE risk undergoing abdominal surgery. Compared withdalteparin, fondaparinux reduced the incidence of VTEfrom 6.1% to 4.6%, an odds ratio reduction of 25.8% (95%CI 49.7–9.5%; P = 0.14) in favour of fondaparinux.Among the 1408 cancer patients analysed for efficacy, fon-daparinux significantly reduced the incidence of venousthromboembolism from 7.7% to 4.7%, an odds reductionof 40.5% (95% CI 61.9–7.2%; P = 0.02). There wereno significant differences between the two groups in theincidence of major bleeding.

Thrombin inhibitorsThe prototype of thrombin inhibitors is recombinanthirudin. This is based on the anticoagulant produced byleeches and can block thrombin independent of antithrom-bin; it is a direct inhibitor. Two clinical studies have shownthat hirudin, given subcutaneously, is more effective thanand as safe as LMWH in the prevention of VTE in patientsundergoing elective hip arthroplasty. Melagatran is anotherdirect thrombin inhibitor that must be given subcuta-neously. At present, the greatest clinical need is for an oralanticoagulant to replace warfarin for long-term preventionand treatment of patients with venous and arterial throm-bosis. Ximelagatran, an oral direct thrombin inhibitor,might meet this need (Hirsh et al, 2005).

Risk Management 103

Venal caval filters and venousthromboembolismSince the early 1900s, surgical interruption of the inferiorvena cava (IVC) has been utilised in the management ofVTE. Newer-generation percutaneous IVC filters wereintroduced in the late 1970s and, since then, their useand indications have expanded (Moores and Tapson,2001). For those patients with established thromboem-bolic disease in which anticoagulation is either ineffectiveor contraindicated, vena caval interruption is generallyaccepted as the standard of care (Jacobs and Sing, 2003).Other indications for filter insertion will remain a matterfor clinical opinion (Table 3.27). Girard et al (2002)conducted a systematic MEDLINE search of vena cavafilters insertion and found a total of 568 referencesbetween 1975 and 2000. Nearly two-thirds (65.0%) ofthese publications were retrospective studies or casereports (33.3% and 31.7%, respectively), 12.9% were ani-mal or in vitro studies, 7.4% were prospective studies,6.7% were reviews and 8.1% reported on miscellaneousrelated topics. Among the prospective studies, only 16studies included 100 patients and only one was an RCT(0.02% of 568 references).

Complications of IVC filter use include acute procedure-related complications: misplacement (1.3% of insertions),pneumothorax (0.02%), haematoma (0.6%), air embolism(0.2%), inadvertent carotid artery puncture (0.04%) andarteriovenous fistula (0.02%) along with a placement mor-tality of 0.13% (Hann and Streiff, 2005). Longer-termproblems include insertion-site thrombosis, recurrent DVT,IVC thrombosis, filter migration, IVC penetration and filterdisruption.

IVC thrombosis is of concern because this can lead tophlegmasia cerulea dolens, recurrent DVT and a height-ened risk of post-thrombotic syndrome and recurrent PEdue to thrombi, which extend proximal to the thrombosedfilter (Hann and Streiff, 2005). Thus Crochet et al (1999)found a progressive decrease in IVC patency in 142 patientsmanaged with a Vena Tech-LGM filter, reaching 66.8% at9 years of follow-up. Complete caval occlusion occurred in28 patients and was significantly associated with retrac-tion in 24 cases. IVC occlusion was not related to age, sex,PE, DVT level, underlying conditions predisposing to athromboembolic disease before filter insertion, the level of

filter placement, use of anticoagulant therapy or deathduring follow-up.

However, post-thrombotic syndrome is also a commoncomplication among patients not treated with an IVC filterfor VTE (Hann and Streiff, 2005). Compression stockingsmay have a role in reducing the incidence of post-throm-botic syndrome: in one study (Brandjes et al, 1997), 194patients with a first episode of venogram-proven proximalDVT were randomly assigned compression stockings (n =96) or no stockings (n = 98). After a median follow-upof 76 months (range 60–96) mild-to-moderate post-thrombotic syndrome occurred in 19 (20%) patients in thestocking group and in 46 (47%) control-group patients(P < 0.001), while severe post-thrombotic syndromewas seen in 11 (11%) patients in the stocking group (score≥ 4), compared with 23 (23%) patients in the control group(P < 0.001). Routine use of compression stockings shouldbe encouraged among all filter patients (Hann and Streiff,2005).

Given the long-term complications of permanent filters,development of a safe and effective temporary filter hasbeen proposed as an alternative to a permanent filter inpatients who have an acute episode of VTE and a short-term contraindication to anticoagulation. Two types ofremovable filtering device are currently available (Jacobsand Sing, 2003): temporary filters and retrievable filters.The temporary filter remains attached to an accessibletranscutaneous catheter, or guidewire, so that removal ofthe filter is easily accomplished and is mandatory. Thesedevices, however, carry a higher risk of insertion-siteinfection, filter thrombosis and filter dislocation.Retrievable filters, like permanent filters, are ‘freestand-ing’ endovascular devices that require repeat endovascu-lar access to accomplish their removal. If, however, thepatient’s need for temporary PE prophylaxis becomes per-manent, these filters may be left in place and treated in afashion similar to that of permanent IVC filters (Jacobs andSing, 2003). Previously, if temporary IVC filtration wasthe desired goal then filters could not be left in place forlonger than 10 days, as endothelial incorporation of thefilter might complicate removal if left too long (Jacobs andSing, 2003). The recovery nitinol filter (RNF), however,can be safely removed up to 134 days after implantation(Asch, 2002).


TABLE 3.27 INDICATIONS FOR INFERIOR VENA CAVA (IVC) FILTER PLACEMENT

Appropriate indication Potential indication Unsubstantiated indicationContraindication Failure of adequate anticoagulation Treatment of VTE in:

to anticoagulation Pulmonary thromboembolectomy patients ● Cancer patientsin established Prophylaxis in high-risk trauma patients ● COPD patientsthromboembolic Extensive free-floating iliofemoral thrombus ● Patients with poor cardiopulmonary reservedisease Thrombolysis of iliocaval thrombus ● Pregnant patients

● Organ transplant patients● Patients with history of GI bleed● Prophylaxis in burn patients● Prophylaxis in bariatric surgery patients

Based on Hann and Streiff (2005).

COPD, chronic obstructive pulmonary disease; GI, gastrointestinal; VTE, venous thromboembolism.

TRANSFUSION AND BLEEDINGMost colorectal surgical resections can be performed with-out the transfusion of blood or blood products. Mynsteret al (2004) compared blood loss associated with rectalcancer surgery before (n = 246; 1991–3) and after theintroduction of total mesorectal excision (n = 311;1996–8). The median intraoperative blood loss was 1000mL (range 50–6000 mL) before and 550 mL (range10–6000 mL; P < 0.001) after introduction of TME. Theoverall perioperative transfusion rate was reduced from73% to 43% (P < 0.001). When adjusted for blood loss,age, gender, weight and type of resection, TME significantlyreduced the risk of receiving intra or postoperative bloodtransfusion by 0.4 (95% CI 0.3–0.6).

Thus, most operations can be performed safely in thosewith faith issues that make transfusion an ethical dilemma(Gohel et al, 2005). Preoperative patients with anaemia orclotting deficiency should be treated by appropriate replace-ment therapy before elective operative intervention.Okuyama et al (2005) demonstrated that, in anaemic col-orectal cancer patients, iron supplementation for at least 2weeks before surgery reduces the need for intraoperativetransfusion. Of 569 patients who underwent colorectalcancer surgery between 1998 and 2003, 32 anaemicpatients received iron supplementation for at least 2 weekspreoperatively (group A) while 84 anaemic patients did not(group B). Anaemia was defined as a haemoglobin level atfirst presentation of ≤ 10.0 g/dL. There were no significantdifferences between groups A and B in age, sex, surgicaltechnique, tumour stage and operating time. Their haemo-globin and haematocrit values were similar at first presen-tation, but significantly different immediately beforesurgery (both P < 0.0001). There were no significant dif-ferences in intraoperative blood loss between the groupsbut significantly fewer patients in group A needed an intra-operative blood transfusion (9.4% versus 27.4%; P < 0.05).

Cross-matching blood is necessary for tumours requiringextensive resection (pelvic exenteration) or in patients withchronic sepsis needing surgical interventions. Nakafusa et al(2004) compared transfusion requirements in locallyadvanced colorectal cancer with and without multivisceralresection. Of 323 patients, 53 (16.4%) received multivisceralresection because of adhesion to other organs. Multivisceralresection was significantly associated with tumour size,depth of invasion, operative blood loss, operation time, andblood transfusion (all: P < 0.0001).

Massive bleeding is uncommon in colorectal practice,alarming haemorrhage is usually venous. Arterial bleed-ing, which can be annoying because access is often poor,may be encountered from the internal pudendal vessels orbranches of the internal iliac artery. Venous bleeding canbe difficult to control if veins near the confluence of theright colic vessels or the superior mesenteric vein areinjured or if splenic hilar vessels are torn. The most alarm-ing form of blood loss to the relatively inexperienced col-orectal surgeon is from presacral veins. Bleeding can beextensive, the pelvis simply fills up with low-pressurevenous blood. van der Vurst et al (2004) encountered thisproblem in five of 165 patients (3%) who underwent a pre-sacral dissection for rectal mobilisation. In these five cases,successful tamponade of presacral haemorrhage was

obtained using absorbable haemostatic sponges fixed to thesacrum with endoscopic helical tackers.

Placing the patient in the steep Trendelenburg tilt sothat the veins are no longer dependent and packing thepelvis tightly allows the surgeon to pursue another part ofthe operative procedure. If the pelvis is not dry when thepacks are removed 1 hour later, then the pelvis shouldbe repacked through the perineum if the procedure hasbeen an abdominoperineal excision (or proctocolectomy) orthrough the abdomen (Metzger, 1988). Application ofhaemostatic gauze to the haemorrhaging point is main-tained by the pressure of several lengths of 6-inch ribbongauze. The gauze may be used dry and the patient is post-operatively nursed in an ITU or HDU setting. Packs are leftin place for 48–72 hours while coagulation studies and thepatient’s haemoglobin are normalised.

Care should be exercised when removing the packs.Pulling adherent gauze from the sacral fascia may causefurther bleeding. Packing the gauze into an intestinal baghas been described as a technique to prevent haemostaticpacks adhering to the sacrum.

The patient should be returned to the operating roomfor removal of the pack with the personnel and equipmentavailable for a full laparotomy, if pelvic haemorrhageresumes on removal of the pack. In selected cases, leavingthe ends of the gauze packs emerging from the lower endof the laparotomy wound allows removal in some instanceswithout laparotomy. Alternatively pack removal is carriedout via a formal laparotomy when pelvic haemostasis canbe checked under direct vision as the packs are removed(Curran and Scott, 2005).

COLORECTAL PATIENTS AND HIGH-DEPENDENCY CARE: EVOLUTION OF THESURGICAL HIGH-DEPENDENCY UNITTraditional postoperative care for abdominal procedures incolorectal patients has been provided by either generalward care or by ITU provision. Two separate observationshave identified the need for care provision intermediatebetween these two levels. First, that within the workload ofa general ITU it has become apparent that a significant pop-ulation is at relatively low risk and might be cared for in anintermediate facility. Thus, Kilpatrick et al (1994) foundthat among 1168 ITU admissions, 40% of patients wereadmitted with a risk of hospital mortality of 10% or less:such patients received only a short period of intensive careand had a low mortality in the intensive therapy unit. Theauthors (Kilpatrick et al, 1994) proposed that a group ofpatients with a low predicted (and actual) mortality ratemight be more appropriately managed on a high-depend-ency unit. Second, it has become apparent from a surgicalperspective that continuous monitoring of some patientsis required in a unit that provides a specified increasedpatient to nurse ratio: a surgical high-dependency unit(HDU) (Crosby and Rees, 1994, Edbrooke, 1996).

In a survey of Scottish HDU provision, surgical HDUsaccount for 41% of the HDUs, 24% are mixed (i.e. cover-ing both medical and surgical), 16% are combined ICU/HDU, 11% are medical and 8% are neurosurgical (see:http://www.scottishintensivecare.org).

Risk Management 105

Coggins (2000) similarly demonstrated that in a hospi-tal without a surgical HDU, at least 5% of the beds on ageneral surgical ward are occupied by inappropriatelyplaced HDU patients. Moreover, the needs of such patientshas an impact on the number of observations made on themore routine patients—the mean of 5.1 observations every24 hours falling to 3.8 every 24 hours in the presence ofan HDU patient (P < 0.02). Accordingly, in UK practice theprovision of surgical HDU has developed on an ad hoc basisout of and alongside the ITU. Nehra et al (1994) proposedthat a 250 000-population UK district general hospitalwould require a six-bed ITU and eight high-dependencysurgical beds in two separate but adjacent units, wherethere will be a free interchange of skills at the differentlevels of care.

Attempts to demonstrate that the introduction of a sur-gical HDU will reduce surgical mortality can be confoundedby other variables in a hospital’s casemix. Thus, in one hos-pital the first 12 months of HDU utilisation was associatedwith an increase in overall surgical mortality from 2.16%to 3.2%; however, in the same 12 months there was a dis-proportionate increase in emergency admissions (27%)and emergency out-of-hours operating (12%) (Davies et al,1999). A more telling demonstration of surgical high-dependency care on surgical outcomes is provided by astudy of 1363 patients undergoing a range of surgical pro-cedures. Postoperatively, 349 were judged by the surgeonand anaesthetist to require HDU provision but only 140(42.3%) actually received HDU care. In the group ofpatients that received optimal postoperative care, the mor-tality rate was 1.2%—significantly better than the 3.1%mortality rate observed among those not receiving the carelevel requested (Turner et al, 1999).

Further evidence for a specific HDU effect on prevent-ing postoperative morbidity comes from comparison ofoutcomes between a surgical population managed on ageneral ward in a hospital with no HDU and a similar sur-gical population managed in the HDU of a second hospi-tal (Jones et al, 1999). Ideally, this study would have beencarried out in the same institution but the two groupswere very comparable in their physiological and opera-tive severity scores. A surgical HDU association was seenin reducing postoperative morbidity, specifically reducingchest infections (25% versus 41%), prolonged hypoten-sion (1% versus 14%) cardiac dysrhythmia (7% versus13%) and wound infection (2% versus 17%) (Jones et al,1999).

Step-down from ITU care is another function of surgi-cal HDU care in the management of colorectal patients.Papagrigoriadis et al (2004) described the hospital careof 148 patients with diverticular disease. Of 982 hospi-tal days, 94 were on an ICU and 68 were on a surgical HDU(Papagrigoriadis et al, 2004). Boots and Lipman (2002)describe the potential of every patient in the ICU to be atsome time classifiable as an HDU patient. In their view, onlyif there is a need for monitoring for more than 12–24hours should a patient move from the ICU to theHDU rather than being discharged to the ward. Otheradvantages to surgical HDU care include:

● Increased patient and nursing satisfaction with the levelof care delivered (Armstrong et al, 2003).

● A consistent and valuable clinical resource for teachingand learning in surgical education and training (Ghoshet al, 2004).

Surgical high dependency unit careDe Silva et al (2001) used the Logistic Organ DysfunctionSystem (LODS) to monitor patient progress in a predomi-nantly surgical HDU, concentrating on a subset of 100patients whose stay on the unit was greater than 48 hours,representing 14.5% of the total HDU admissions over thestudy period. Sixty-six patients’ LODS scores improvedduring their HDU admission, whereas in 20 patients theLODS scores remained the same and for 14 the LODS scoreincreased. These 14 patients were older than the otherpatients and required longer HDU admission; the 14includes the two patients who died and the patient trans-ferred to the ICU (De Silva et al, 2001).

Care within a surgical HDU is likely to reflect the patientcasemix and the evolution of local policies in the provisionof critical care. For now, the colorectal surgeon is stillexpected to manage patient illness that commonly arisesafter colorectal surgery. The clinical roles of the surgicalHDU include accurate fluid management, invasive moni-toring, good oxygenation and optimal pain relief. In addi-tion, the surgical setting of the HDU acts to maintain theinvolvement of the operating surgeon in the critical care ofthe patient in whom they have undertaken a procedure(Coggins and Cossart, 1996). For the minority of patientswho require extended HDU care, nutritional assessment isalso required. Kinn and Scott (2001) examined HDU-basednutritional care. They found that the most common formof supplementary feeding was total parenteral nutrition(TPN), the choice of supplementary feeding being depend-ent on the type of surgery and the individual patient’scondition.

The Scottish Intensive Care Society conducted a tele-phone questionnaire in April 2000 to assess the provisionof high-dependency care beds across Scotland. As well asidentifying the number of HDUs and their bed complement,the survey assessed the extent of the variation in nursingprovision and the range of critical care interventions thateach unit could provide. Almost every acute hospital hadhigh-dependency facilities available for surgical patients.Surgical HDUs provide transduced monitoring of centralvenous and intra-arterial pressures, and the majority areable to infuse inotropes and care for patients withtracheostomies (Figure 3.9).

Ng and Goh (2002) studied 471 patients that hadepidural catheters inserted for postoperative analgesia.Ninety per cent of patients received continuous local anaes-thetic infusion (75% ropivacaine and 15% bupivacaine) and10% received intermittent morphine boluses. There werefew serious complications but 60% of patients required oneor more interventions, mainly for inadequate analgesia.One-third of patients had their epidural analgesia termi-nated prematurely due to inadequate analgesia (14.2%),shortage of beds in the HDU (14%) and other complications.Only 19% of patients had no reported adverse effects.Coggins et al 1998 documented changes in pain relief tech-niques in surgical HDU admissions (Figure 3.10), with alarge increase in the use of epidural analgesia.


Batra et al (2001) reported on 226 colorectal patients(colorectal cancer and inflammatory bowel disease) admit-ted to a surgical HDU over a 12-month period. A total of29 patients (13%) had significant arrhythmias on ECGmonitoring (median age 74 years, range 35–88 years).Pre-existing ischaemic heart disease, which was present innine patients, accounted for the underlying problem in the

majority of these patients. Equal numbers of supraven-tricular and ventricular arrhythmias were detected, atrialfibrillation being the most commonly detected abnormal-ity. Therapeutic intervention (electrolyte correction andanti-arrhythmic agents) was required in 23 patients. Onepatient required DC shock for ventricular fibrillation. Sevenpatients were transferred to the heart-care unit or inten-sive care unit to manage their cardiac problems. Twopatients died as a result of their cardiac problem and 27were discharged home alive, three on long-term anti-arrhythmic therapy.

The key to successful HDU care is multiprofessionalteam care in which the surgical team, HDU nurses andanaesthetic/intensivist colleagues assess patients for post-operative organ dysfunction and intervene early to preventorgan failure. In this context, the following represent com-mon HDU assessments and interventions.

ANAESTHESIA FOR COLORECTAL SURGERYPreoperative assessmentAdequate preoperative assessment is important to iden-tify existing medical conditions, potential anaesthetic dif-ficulties and to plan perioperative care. It also gives anopportunity for the patient to receive an explanation ofthe anaesthetic and ask questions. Patients should alwaysbe seen by an anaesthetist preoperatively, but basicscreening and assessment can be organised in a varietyof ways. Trained nurses, working to agreed protocols, canidentify patients who need minimal investigation or thosewho require further assessment and referral. Thisarrangement can improve efficiency and enhance patientcare. All patients with intercurrent disease should havetheir condition optimised prior to surgery. Very fewpatients will be deemed unfit for anaesthesia but manyare ill-suited to the stress of the intended procedure andmay be predicted to have a difficult postoperative course.

Risk Management 107

Epidural

CVP

IV analgesia

Patient controlledanalgesia

Thrombolysis

250

200

150

100

50

0

1991−92 1993−941992−93 1994−95

Figure 3.10 Changes in epidural use in surgical high-dependency unit admissions. From Coggins et al (1998).

Epidural

CVP line

Arteria

l line

ECG mon

itor

Trac

he

Inotro

pes

CPAP mas

k

ET tub

e

PA cathe

ter

Ventila

tion

Renal

Intervention

0

10

20

30

40

50

60

70

80

90

100

Per

cent

age

of u

nits

Figure 3.9 Interventions in Scottishhigh-dependency units.

It is inappropriate to discuss detailed preoperative assess-ment here and general references are given at the end ofthe chapter. It is, however, sensible to list some of thecommon problems that affect the management of anaes-thesia and recovery, many of which not infrequently slipthrough the net.

Cardiovascular diseaseIschaemic heart diseaseIschaemic heart disease is common—often occult—andthere may well be no signs or symptoms present. Anymaintenance therapy should be continued peroperatively.Postoperative hypoxia can precipitate cardiac ischaemiaand compromise pump function. Cardiac pain may be

masked by postoperative analgesia and the episode canpresent as an acute confusional state. Diagnosis is clinicaland by ECG and isoenzyme changes. Because of the rela-tively high incidence of incidental abnormalities, allpatients over 60 years old should have a recent preopera-tive ECG available for comparison. Echocardiography maybe valuable to assess left ventricular function and anyvalvular abnormality.

HypertensionHypertensive patients are at increased risk duringthe perioperative period. Complications of hypertensioninclude ischaemic heart disease, heart failure, cerebro-vascular disease and renal impairment. The presence of


Monitoring Assessment InterventionsRespiratory rate Clinical examination/chest X-ray, Increase FiO

2

Pulse oximetry ABGs, ARDS CPAPITU referral

ABG, arterial blood gases; ARDS, acute respiratory distress syndrome; CPAP, continuous positive airway

pressure; ITU, intensive treatment unit.

Monitoring Assessment InterventionsPulse rate Clinical examination Fluid bolusBlood pressure Observation trends Exclude haemorrhageUrine output Dopamine

ITU referral

ITU, intensive treatment unit.

Monitoring Assessment InterventionsPain score Clinical examination Epidural adjustment

Respiratory effort PCA

PCA, patient controlled analgesia.

Monitoring Assessment InterventionsECG trace Clinical examination Correct electrolytes

K+/Mg2+ ITU/cardiology consult Acid–base balance (anti-arrhythmic

drugs/DC shock)

ITU, intensive treatment unit.

Oxygenation and respiratory function

Haemodynamic stability

Analgesic requirements

Cardiac arrhythmia

these is a major contribution to perioperative cardiac risk.Repeated measurements should be taken to minimise theeffect of ‘white coat’ hypertension. Investigations shouldinclude:

● ECG: no evidence of left ventricular hypertrophy,conduction abnormalities or dysrhythmias.

● Chest X-ray: no evidence of ventricular dilatation.● Full blood count: no evidence of polycythaemia.● Urea and electrolytes: no evidence of renal/endocrine

involvement. Mild hypokalaemia is unlikely to be associ-ated with intraoperative dysrhythmias but levels below3 mmol/L should probably be treated.

● Serum glucose: not diabetic.

Although the evidence is unclear, it would seem sensible topostpone patients for routine surgery who have a systolicblood pressure > 180 mmHg or a diastolic pressure of> 110 mmHg. Blood pressure is best normalised over a periodof weeks although in urgent cases this may not be possi-ble. Very rapid control of blood pressure may increase mor-bidity and mortality. The problems specific to hypertensivepatients are the following:

● There is a greater blood pressure lability especially duringinduction and at laryngoscopy.

● Arrhythmias are more common.● Increased levels of afterload and cardiac work predispose

to myocardial ischaemia and infarction.● Interactions may be anticipated between antihyperten-

sive and anaesthetic agents.

Perioperative care may require invasive monitoring andadmission to an HDU. It is important to prescribe postoper-ative maintenance therapy. As the oral route is usuallyinappropriate following colonic surgery this implies achange to a parenteral or alternative preparation.

Pulmonary diseaseChronic obstructive airways diseasePatients with chronic obstructive airways disease(COAD) have a 20-fold increase in postoperative pul-monary complications compared to healthy adults.Preoperative assessment and treatment should be aimedat optimising the patient’s respiratory status. A historyof dyspnoea, limitation of physical activity, sputum pro-duction and clinical examination give a good indicationof the patient’s pulmonary function and are usefullyaugmented with arterial blood gas analysis and lungfunction tests.

Although in many cases the likely outcome is easy topredict, the only studies of the results of preoperativelung function tests to postoperative complications relateto lung resections. Some general deductions can,however, be made. If the tidal volume (VT) is close to thevital capacity (VC), then there is little ‘ventilatory reserve’and the adequacy of postoperative ventilation easilydeteriorates with opioids and residual neuromuscularblock (including that provided by a thoracic epidural).Irrespective of the cause, perhaps the most importantfeature of low values of the forced expiratory volume in1 second (FEV1) and the peak expiratory flow rate (PEFR)is an indication that the patient cannot expel air rapidly.

Although these tests are not a direct measure of the‘power’ of a cough, they are closely related to the abilityto expel sputum. An FEV1 of < 2 L or an FEV1 : VC ratioof less than 50% are sometimes quoted as values whichdefine serious disease.

Arterial blood gas analysis showing a pO2 less than 7.1kPa in association with dyspnoea at rest predicts depend-ence on respiratory support postoperatively in upperabdominal surgery. A raised pCO2 may indicate a patient isfunctioning on a hypoxic respiratory drive and will requirecontrolled oxygen therapy postoperatively.

All patients with significant pulmonary dysfunctionneed to be cared for postoperatively in an appropriatesetting. This care needs to include regular observa-tions to detect and treat hypoxia and meticulous atten-tion to fluid balance and analgesia. Pulse oximetry canbe invaluable.

AsthmaIn addition to clinical assessment the most sensitive indicesof bronchial tone are the PEFR and FEV1. Bronchospasmand infection should be controlled prior to elective surgeryand it is important to allow patients to continue their nor-mal medication up to the time of operation. Prophylacticantibiotic therapy is indicated for people with severeasthma. All patients need a chest X-ray, both as a baselineand to show the presence of bullae and hyperinflation.

The three most common problems during anaesthesiaare bronchospasm on intubation or during gas induction,the risk of a pneumothorax when on intermittent positivepressure ventilation (IPPV) and bronchospasm secondaryto thiopental or other histamine-releasing drugs such asatracurium, suxamethonium, morphine, etc.

Adequate premedication is important if the patient isnervous, because an attack can be precipitated by fear.

An asthmatic attack in the postoperative period shouldbe treated in the normal way. Maintenance therapy mayneed to be changed from the inhalation to the parenteralroute in the immediate postoperative period.

DiabetesApproximately one-quarter of all diabetic patients under-going surgery are undiagnosed on admission to hospital.Almost all of these fall into the ‘adult onset’ type, i.e. indi-viduals who have a small but insufficient insulin produc-tion. It is therefore necessary to have a high index ofsuspicion that diabetes may be present in any patient, espe-cially if obese and over 60 years old. The stress of surgerymay precipitate frank diabetes in a previously undiagnosedpatient.

Diabetes has widespread physiological effects relevantto preoperative assessment, the most important of whichare listed systemically below.

● Cardiovascular effects: evidence of angina, myocardialinfarction, intermittent claudication, gangrene and pos-tural hypotension (systolic fall of > 30 mmHg on stand-ing) should be sought.

● Neurological complications: neurological involvement maybe evident as numbness, pain, paraesthesia, leg ulcers,strokes, transient ischaemic attacks, impotence or gustatory

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sweating. Postural hypotension is a late sign of autonomicneuropathy; loss of heart rate variability during deepbreathing is the most reliable early sign.

● Renal complications: range from minimal proteinuria tochronic renal failure with secondary complications ofanaemia and/or hypertension.

● Skin: staphylococcal infections are common and there isan increased risk of sepsis, especially over the pressureareas.

Most of the excess perioperative mortality of diabetes isrelated to cardiovascular comorbidity but good metaboliccontrol is also important. Non-insulin-dependent diabeticscan usually be managed by omitting their hypoglycaemicon the morning of surgery but insulin-dependent diabeticsand all those undergoing major surgery will require insulinperioperatively. Regular blood glucose estimations andadherence to local protocols are vital to safe management.

Bowel preparationBowel preparation agents (e.g. Picolax) may lead to markeddehydration and subsequent hypotension and oliguriaintraoperatively. Patients should be encouraged to drinkadequate amounts orally or receive intravenous fluidspreoperatively.

Selection for day-case surgeryMany minor surgical procedures may be considered to beappropriate for admission as day cases. The surgicalprocedures should usually last no longer than an hour,although no absolute time limit is necessary. Patientsshould be assessed for their suitability on both medical andsocial criteria and this requires preoperative screening andconsistent protocols in each unit. They should be in goodgeneral health and any chronic disease (e.g. asthma, dia-betes, epilepsy) should be well controlled. Grossly obesepatients should be excluded. Patients need to be accompa-nied home, have an adult carer for at least 24 hours, haveaccess to a telephone and be able to return easily to thehospital if problems occur.

Intraoperative techniquesFor the well-prepared elective bowel resection, the require-ments are abdominal muscle relaxation and lack ofresponse to surgical stimulae, preferably with contractedintestines. This state of anaesthesia can be achieved by gen-eral or local techniques, or by a combination of both. Inthe UK, the majority of colonic resections are done undergeneral anaesthesia using muscle relaxation. This gives asmooth intraoperative course but can produce problemsduring reversal and postoperatively (see below).Increasingly, anaesthetists are combining general anaes-thesia (to achieve unconsciousness) with some form ofregional blockade (to achieve analgesia), which can be car-ried into the postoperative period for pain relief. Patientswith a dense regional blockade who are awake during sur-gery are rarely seen in the UK, although it is not uncom-mon in some other European countries such as Sweden. Incertain instances (e.g. intestinal obstruction), the condi-tion dictates specific techniques (e.g. rapid sequence induc-tion with cricoid pressure in order to prevent aspirationpneumonitis).

Local anaesthetic techniquesLocal anaesthetic techniques have an undeserved reputa-tion for safety (particularly in the compromised patient),which tends to obscure their dangers. All local anaesthet-ics can produce direct toxicity and adverse side-effects. It isimportant that those who employ them can recognise andtreat these complications. For this to be so, local anaes-thetics should be used only in environments where fullresuscitation facilities and the staff who know how to usethem are available. A surgical procedure in a fully con-scious patient should not be pushed on to unwilling ornervous patients and all members of the operating theatrestaff need to know and to be constantly reminded that thepatient is awake.

For colorectal surgery there are only a limited numberof ways in which local blocks can be used and none ofthem interrupt the vagus nerve. This can be a nuisancebecause traction on the mesentery and viscera often resultsin unwanted bradycardia and, in the awake patient, canproduce intense nausea.

InfiltrationThis is suitable only for operations on the anal canal, whereit can be very successful. From a point 2.5 cm posterior tothe anus (with the index finger of the left hand in therectum), 25 mL 1.5% lidocaine–adrenaline solution isinjected. Only one site of injection is necessary andthe anus and anal canal are ensheathed by a cylinder ofsolution. Local infiltration is very successful in suitablyselected patients having sphincterotomy excision of analskin tags (often with rubber band ligation) and around alow lying anal fistula being laid open. Local infiltration canalso be used for excision of pilonidal sinus if simple andexcision of condylocmata.

Caudal blockThis is a form of epidural blockade achieved through thesacral hiatus. It is usually performed as a one-shot proce-dure and requires proper sterile precautions. The sacralcanal, in addition to housing the nerves to be blocked, alsocontains the dural sac (usually attached to the secondsacral vertebrae), and a venous plexus. It is therefore quitepossible to inject large quantities of local anaesthetic solu-tion both intravascularly and into the subarachnoid space:both of these events can be disastrous if not detected andtreated promptly.

When local anaesthetic solution is injected into thesacral canal it ascends upwards in the extradural space fora distance proportional to the volume of the solution, theforce of injection, the amount of leakage through the eightsacral foramina, and the consistency of the connective tis-sue in the sacral space. While the first two are controllable,the last two are not and unexpected results can occur. Inan average man, 30 mL of local anaesthetic solution willblock to L2–L4 (the whole perineal area) and 20 mL willsuffice for haemorrhoids or anal fissure. If surgeons do notlike a relaxed anal sphincter during surgery, the block canbe instituted after surgery but before awakening, for post-operative pain relief. Urinary retention is an easily missedcomplication of the block which, in the elderly, can presentas confusion.


Epidural blockThis is blockage of the nerve roots outside the dura. Withinthe relevant peripheral nerve distribution it gives relaxationof muscles, analgesia and a degree of hypotension depend-ent upon the extent of sympathetic blockade. Unless theblock goes to an unpredictably high level it allows sponta-neous respiration with the diaphragm, although the inter-costals may be compromised. Like other forms of regionalblockade it suppresses afferent impulses secondary topainful stimuli and the hormonal and autonomic responsesto surgery. A catheter is usually introduced into theepidural space so that the block can be continued into thepostoperative period. One of the advantages of epiduralblockade is that it allows a ‘band’ of analgesia to beestablished without paralysis of the lower limbs.

When the epidural space has been identified, the extentof the block is influenced by the volume and concentrationof solution injected, the age of the patient (the aged needless), the location of the catheter (thoracic segments needless than lumbar segments for each dermatome), the lengthof the vertebral column and the presence of large abdominaltumours. The exact extent of block secondary to a givenvolume of local anaesthetic is unpredictable to a highdegree of accuracy.

Epidural blockade has several complications, which canoccur during ‘top-ups’ on the postoperative ward as well asat the time of insertion. Those most likely to causeproblems are:

● Inadequate block, unilateral block or missed segments.● Hypotension and cardiovascular depression from sympa-

thetic blockade. This requires oxygen, intravenoussolutions, pressor drugs and, if there is a bradycardia,atropine.

● Toxicity due to absorption of the injected drug (eitherlocal anaesthetic or opioid).

● Unexpected respiratory depression.● Unexpected total spinal anaesthesia, sometimes from

migration of the catheter into the subarachnoid space.This is life threatening and requires immediate action.A typical dose of epidural local anaesthetic (10 mL) isapproximately five times the volume of drug required toproduce the same level of block when injected into thesubarachnoid space.

● Nausea, vomiting and shivering.● Unexpectedly prolonged analgesia.

Because of the potential complications of epidural analge-sia, all patients receiving it postoperatively should benursed in a suitable environment with ready access toanaesthetic support. All catheters should be inspected afterremoval and recorded as being intact. Although extraduralabscesses are rare, many anaesthetists are reluctantto establish or continue with epidural analgesia in thepresence of systemic sepsis.

Other absolute contraindications to regional blockadeare local sepsis, patient refusal and the presence of a coagu-lopathy or therapeutic anticoagulation because of the riskof epidural haematoma formation and subsequent neuro-logical damage. There is controversy concerning the use ofthese techniques in patients receiving prophylactic low-dose heparin or aspirin. There is no firm evidence that this

will increase the risk of epidural haematoma and abalanced judgement as to the risks and benefits of thetechnique needs to be taken for each patient. If possible,regional anaesthesia should be undertaken before the firstdose of unfractionated heparin is given or delayed until6 hours after the previous dose (Bullingham and Strunin,1995). A 12-hour interval has been recommendedfollowing low molecular weight heparin. Similarly, somewould consider that aspirin therapy should ideally bestopped for 7–10 days before instituting a regional blockor before a bleeding time is performed.

Other relative contraindications include neurologi-cal disease and some forms of cardiac disease (e.g. aorticstenosis).

Subarachnoid (spinal) blockSubarachnoid block entails performing a lumbarpuncture and injecting local anaesthetic directly into thecerebrospinal fluid (CSF). Although the use of very finecatheters has been reported, spinal block is essentially asingle-shot technique.

Unlike epidural block, when local anaesthetics areinjected into the subarachnoid space they effectively pro-duce a pharmacological transection of the cauda equinaand spinal cord at the upper level of the solution. There isno sparing of any fibres or tracts and if the abdomen is tobe anaesthetised then the lower limbs are automaticallyparalysed. The highest dermatome reached depends onthe volume and concentration of solution, the force andrate of injection, the position of the patient, the interspacechosen and the specific gravity of the solution.

The most common intraoperative complication is a fallin blood pressure from sympathetic blockade, which, if nec-essary, is treated with fluid and vasoconstrictors. As longas the block is acting, retention of urine remains a possi-bility and the immobility of the patient may lead toischaemia over pressure areas. If the block does not startto regress at the expected time the anaesthetist should becontacted at once.

The most common postoperative complication isheadache. The classic spinal headache is a low-pressureheadache that is worse in the upright posture and relievedby lying down, and may be associated with meningism andphotophobia. It is seen most commonly in young adults(females more than males) and is closely related to thesize and type of needle used; the larger the needle, thegreater the incidence of headache. The majority of spinalheadaches can be managed by bed rest, adequate hydra-tion and simple analgesics. If the headache does not settlewithin a day or so, consideration should be given to per-forming an epidural blood patch.

The introduction of pencil-point needle tips and finer-gauge needles have significantly lowered the risk of post-dural puncture headaches and hence spinal techniquesmay be satisfactory for day patients.

Anastomosis and anaesthesiaMorbidity and mortality from gastrointestinal complicationscan result indirectly from the effects of anaesthesia on car-diovascular and respiratory function, or directly from theeffects of drugs and anaesthetic manoeuvres on the bowel.

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Drugs and gastrointestinal activityMany of the drugs that are administered intraoperativelycan potentially affect intestinal activity.

The anticholinesterase neostigmine used to reverse neu-romuscular block may increase bowel activity and intra-luminal pressure and reduce colonic blood flow, henceincreasing the risk of anastomotic leak (Bell and Lewis,1968; Whittaker, 1968). No large, well-controlled serieshave assessed the detailed effect of neostigmine or the anti-cholinesterases atropine or glycopyrollate on the humancolon in clinical practice. It is frequently possible to avoidthe use of neostigmine in modern practice (Hunter, 1996).

Halothane depresses intestinal and colonic contractionsand antagonises the effect of morphine and neostigmineon the bowel (Marshall et al, 1961). Diazepam depressesgastrointestinal motility (Birnbaum et al, 1970) andmetoclopramide, although it generates contractions, mayprolong ileus because the contractions are uncoordinatedand non-propulsive (Jepsen et al, 1986).

Morphine increases the tone of the small and largeintestine but decreases motility. The effects can be antago-nised experimentally with naloxone. It has been suggestedthat in patients with diverticular disease morphine shouldbe avoided because of the risk of colonic spasm and diver-ticular perforation (Painter and Truelove, 1964a). It hasalso been suggested that because of its spasmolytic effectspethidine may be the analgesic of choice following intes-tinal anastomosis; on the other hand it may contribute topostoperative ileus in view of its atropine-like action(Painter and Truelove, 1964b; Ekbom et al, 1980).

Spinal and epidural anaesthesia increase motility in thecolon because blockade of the sympathetic nerves allowsthe parasympathetic to act unopposed. Disruption of acolonic anastomosis in the early postoperative period hasbeen attributed to the increased contractility associatedwith extradural blockade (Bigler et al, 1985) but morerecent evidence contradicts this (Holte and Kehlet, 2001).

Colonic blood flowWhittaker and colleagues (Whittaker, 1968; Whittakeret al, 1970) concluded that the blood flow to the bowel wasthe most important factor in the healing of an anastomo-sis and that a 10% reduction in blood volume fromhaemorrhage markedly increased the risk of anastomoticbreakdown. Schrock et al (1973) found a high anastomoticleakage rate when the blood pressure fell below 50 mmHg.Blood viscosity is cited as being an important factor inwound healing and there is a theoretical optimal haemat-ocrit at which the balance between oxygen carriage andviscosity maximises the oxygen delivery to the tissues: thisis about 11 g/dL, which corresponds to a haematocrit of35% (Gruber, 1970).

Colonic perfusion is regulated extrinsically by the sym-pathetic and parasympathetic systems: intrinsically, arte-riolar and precapillary tone are modulated by cellularmetabolites, and arteriolar smooth muscle contractilityresponds to stretch, providing some myogenic autoregula-tion. There are thus many ways in which anaesthesia andits effects can affect colonic blood flow.

Halothane decreases vascular resistance and increasesmesenteric blood flow. Enflurane produces little change but

isoflurane, surprisingly, was found to increase splanchnicvascular resistance (Tverskoy et al, 1985). However, isoflu-rane can suppress the reflex vasoconstriction in the renaland intestinal blood vessels in response to surgical stimu-lation, and to this end its effects were beneficial (Ostmanet al, 1986). All these effects of volatile agents are dosedependent and motility returns to normal as the drug iseliminated. Thus, volatile agents are unlikely to alter thepostoperative course by effects on gut motility, althoughthey may modify the effects of other drugs given during theoperation. Nitrous oxide diffuses into gas-containing vis-cera more rapidly than nitrogen diffuses out, with result-ant distension of the bowel. This distension may hamperabdominal wall closure, predispose to ileus and interferewith colonic blood flow (Lewis, 1975); there are no harddata to quantify these theoretical problems in patients.

If it is necessary to administer vasoactive agents thereis considerable potential for altering colonic blood flow.Direct or indirect action on the splanchnic and lumbarcolonic nerves decreases blood flow by vasoconstriction.Adrenaline and noradrenaline increase colonic vascularresistance and decrease blood flow and oxygen uptake; iso-prenaline increases colonic perfusion but appears to haveno effect on oxygen uptake. Vagal stimulation has littleeffect on colonic blood flow, but activity in the parasym-pathetic pelvic nerves causes intense hyperaemia.

Spinal and epidural anaesthesia vasodilate the bodycaudal to the height of the block. Blood flow to the bowelreflects the balance between the degree of vasodilatationand the reduction in systemic arterial perfusion pressure.In dog models, a 22% increase in colonic blood flow hasbeen recorded with the onset of epidural block (Aitkenheadet al, 1980). In humans, although retrospective studieshave suggested a reduction in anastomotic breakdownwith the use of spinal block, this has not been confirmedby prospective studies (Worsley et al, 1988). Althoughspinal block may well improve colonic blood flow, anyimprovement may be negated by haemorrhage or the useof vasoconstrictors.

In summary, there are therefore no definite conclusionsto be drawn that can at present recommend any one par-ticular intraoperative anaesthetic technique as being supe-rior to another, given that patients are well oxygenated andhydrated.

Perioperative blood transfusionAdequate perioperative fluid replacement is necessary tomaintain vital organ function. Blood transfusion may beassociated with many unwanted sequelae including infec-tion and allergic reactions. Subsequent immunosuppres-sion is well described, probably due to donor leucocytescarrying foreign antigens and this may be associated withincreased tumour recurrence rate after colorectal surgery(Wheatley and Veitch, 1997). To reduce this risk, leuco-cyte-depleted blood has been used, as have a variety ofmethods to reduce the requirement for homologous bloodtransfusion. There has also been a move, over the past fewyears, towards accepting a lower perioperative haemoglo-bin level in otherwise fit patients. This may even improvetissue perfusion, providing that the circulating fluid volumeis maintained.


Anaesthesia for minimally invasive surgeryLaparoscopic techniques for abdominal surgery offer anumber of advantages, including reduced postoperativepain, low postoperative pulmonary dysfunction and aquicker recovery. However, the effects of a pneumoperi-toneum, changes in position and prolonged surgery mayhave significant adverse effects, especially in patients withpre-existing cardiorespiratory disease.

A steep Trendelenburg position will cause a cephaladmovement of the diaphragm leading to a reduced func-tional residual capacity, reduced lung volume and pul-monary compliance and possibly a deterioration inventilation/perfusion matching. The pneumoperitoneumwill exacerbate these changes. If carbon dioxide is used asthe insufflating gas, this will be absorbed systemically, lead-ing to a progressive rise in carbon dioxide excretion whichusually plateaus after 20 minutes. This is an importantperiod for careful monitoring since intravascular carbondioxide can be fatal. A significant gas embolus is charac-terised by a sudden fall in expired carbon dioxide andcardiovascular collapse. Monitoring with capnographyis mandatory as is good communication betweenanaesthetist and surgeon.

The Trendelenburg position produces an increasedvenous return and central venous pressure which mayproduce deleterious effects in those with coronary arterydisease or ventricular dysfunction. Intra-abdominal insuf-flation is associated with a marked reduction in cardiacoutput due to a diminution of venous return and increasedsystemic vascular resistance. Splenic and mesenteric bloodflow may also be deleteriously affected. These side effectsare all increased if the laparoscopic procedure provesdifficult and is of long duration.

In addition, the anaesthetist may have to deal withthe other consequences of surgical complications such aspneumothorax and vascular trauma (Brichant, 1995).

Postoperative careAll patients recovering from general or regional anaesthe-sia should be admitted to a properly staffed and equippedrecovery room until they are in a satisfactory condition toreturn to the general ward. There should be adequateprovision of high-dependency beds for patients undergo-ing major surgery or for those with significant intercurrentdisease, thereby allowing appropriate analgesia andphysiological support postoperatively. The use of high-dependency beds allows proper intensive therapy facilitiesto be used only for those patients requiring a higher levelof respiratory or cardiovascular support.

The major effects of anaesthesia on pulmonary gasexchange in the postoperative period depend upon the siteof surgery. In the operative and immediate postoperativeperiod the functional residual capacity (FRC) is reducedwith alveolar gas trapping and there is an increased right-to-left shunt. The cause is unknown but it can produce afall in PaO2 of up to 30 mmHg (4.0 kPa) when breathingair compared with the preoperative level. It is easily cor-rected by giving 30–40% oxygen through a facemask. Afterthe first hour or two most patients reverse these changesand effectively return to their normal preoperative state.However, when patients with previously healthy lungs

undergo abdominal surgery this reduction in oxygenationcontinues for at least 48 hours and may extend for up to 5days. This effect is worst with upper abdominal, thoracicand paramedian incisions and least with lower abdominalincisions. Factors known to exacerbate these effects arewound pain (prevents deep breathing, can reduce vitalcapacity by up to 50% and reduces expiratory force),abdominal distension (splints the diaphragm), the supineposition (when the relationship of FRC to closing volumeis least favourable) and overtransfusion (tendency to pul-monary oedema).

All the above changes are intensified in patients withpoor preoperative lung function, cigarette smokers, theobese and the aged. They are also the groups most at riskfrom infection and segmental collapse secondary to sputumretention.

Postoperative pain reliefEffective postoperative pain relief is important not only forhumanitarian reasons but may also confer other benefits:

● Pain relief can aid rapid mobilisation, thus reducing thecomplications of bed rest (deep vein thromboses andpressure sores).

● Pain may inhibit effective ventilation and expectorationresulting in hypoxia and the development of chest infec-tions. Good pain relief also facilitates effective physio-therapy.

● Pain produces hypertension and tachycardia and inhibitssleep. This can produce tiredness, irritability and myocar-dial ischaemia in susceptible persons.

● There is also good evidence that effective pain reliefreduces the detrimental components of the metabolicstress response to surgery.

There is a tremendous variability in individual require-ments for postoperative analgesia. This is related to the siteof surgery, pharmacokinetic and pharmacodynamic vari-ability, the psychological make-up of the patient and theexpectations of the ward staff. Regular recording of painpostoperatively allows proper assessment and audit of theproblem and may, in itself, improve the administration ofanalgesia (Gould et al, 1992). Recording may take the formof a visual analogue scale or a simple scoring system. It ispreferable that the pain scores are recorded on the samesheet as a sedation score and other routine postoperativeobservations including respiratory rate, pulse and bloodpressure. Acute pain services are well established in manyhospitals and are instrumental in education, audit andresearch and promoting safety.

The several ways in which postoperative pain can bemanaged are described briefly below.

Oral analgesiaOral analgesia for minor procedures may include para-cetamol, codeine and tramadol. The latter is associatedwith less constipation than codeine. Non-steroidal anti-inflammatory drugs are useful for relieving the pain ofminor surgery and may also be used after major surgeryfor their morphine sparing effect. Side-effects may includerenal dysfunction, bronchospasm and peptic ulceration.Recent clinical guidelines on their use have been

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published by the Royal College of Anaesthetists (RoyalCollege of Anaesthetists, 1998). Cyclo-oxygenase IIinhibitors may be associated with a reduction in some sideeffects. Oral morphine is effective if gastrointestinal func-tion is intact.

Intramuscular opioidsThe administration of an intramuscular opioid drug on an‘as required’ basis produces peaks and troughs of analge-sia and provides poor control of pain. This can be improvedby with more frequent dosing guided by an algorithmincorporating pain and sedation scoring. However, themethod obviously entails repeated painful injections.

Intravenous opioid infusionsThese are best established with an intraoperative loadingdose and then continued into the postoperative period.Properly managed they can be very effective and havethe advantage of being able to be titrated to individualneed by the nursing staff. The major danger is the risk ofserious respiratory depression occurring and respiratorymonitoring is mandatory. It is the view of many anaes-thetists that this form of analgesia should not be used out-side an intensive therapy unit, high-dependency unit orother specialised environment.

Patient-controlled analgesiaThe basis of patient-controlled analgesia (PCA) is thatpatients are able to control how much analgesia theyreceive, within the limits set by the prescribing doctor. Toset a PCA regimen it is necessary to decide several factors,e.g. type of drug, size of bolus dose, lock-out interval,background infusion rate (if any) and total dose permis-sible within a given time interval. PCA is usually used toadminister drugs intravenously but has also been used byintramuscular, subcutaneous or extradural routes.Several studies have shown that the use of PCA is associ-ated with a lower total dose of drug and superior patientsatisfaction.

Caudal blocksThese have been described above and, using bupivacaineon a single-shot basis, provide several hours of effectiveanalgesia for operations on the anus and perineum.

Spinal techniquesOnly spinal opioids are relevant to postoperative pain con-trol because local anaesthetics are short acting and spinalblocks cannot be topped up. Spinal opioid receptors exist,probably in the substantia gelatinosa, and their action isthought to be presynaptic, reducing the release of sub-stance P from the first-order pain neurons. Analgesia fromintrathecal morphine typically lasts for 24 hours and themajor danger is respiratory depression, which may notoccur maximally for several hours. Some of the complica-tions of spinal anaesthesia have been given above in thesection on subarachnoid (spinal) block. Careful monitor-ing of respiration is essential after the administration ofspinal opioids. The side-effects of spinal opioids are similarto those of epidural opioids.

Epidural techniquesWell-conducted epidural analgesia should provide the goldstandard for pain relief at rest and on movement. Other ben-efits may include a reduction in perioperative myocardialischaemia, attenuation of the stress and metabolic response,improvement in pulmonary function and a reduction inthromboembolic complications. Epidural analgesia allowsthe avoidance of systemic opioids and a reduction in sym-pathetic activity. This should reduce the duration of post-operative ileus and improve bowel blood flow. Meta-analysishas been disappointing in showing little improvement inoverall outcome with epidural analgesia and there has beenmuch discussion why this may be, including variation inepidural technique, efficacy of epidurals in the studies andend points of therapy (Ballantyne, 2004). There is evidenceto suggest that an improved outcome may be obtained ifused as part of a multimodal rehabilitation strategy includ-ing limited surgical injury, maintenance of normothermia,early enteral nutrition and early post operative mobilisation(Wilmore and Kehlet, 2001).

To cover the required dermatomes and to minimiselower limb blockade a thoracic approach to the epiduralspace is most appropriate. It is, however, more technicallychallenging and carries a greater risk of accidentalneurological damage.

Most commonly, opioids or local anaesthetics are givenby the epidural route although other agents e.g. clonidine,have been used. Drugs may be used as sole agents or incombination. A mixture of a low concentration of a localanaesthetic, e.g. bupivacaine 0.1%, and an opioid, e.g. fen-tanyl, given by continuous infusion will usually provide thebest analgesia and limit the hypotension caused by localanaesthetic alone and the effect on gut motility producedby epidural opioid alone. (Wheatley et al, 2001). The useof local anaesthetic alone provides the best conditions fora rapid return to normal gut motility (Holte and Kehlet,2000). Drugs may also be delivered by PCA or bolusmethods.

Epidurals need to be managed aggressively by the acutepain team to maintain efficacy. This may include earlycatheter replacement if the block is inadequate.

Postoperative nausea and vomitingMany patients consider nausea and vomiting to be the mostunpleasant aspect of their postoperative course and may,for example, desist from using a patient-controlled analge-sia pump to avoid this complication. There may also bemore serious effects, including wound dehiscence, bleed-ing, dehydration, electrolyte imbalance as well as economicsequelae from increased recovery room stay and unantic-ipated admission after day surgery (Reynolds and Blogg,1995). The reported incidence of postoperative nauseaand vomiting (PONV) is very variable but is increased infemales, non-smokers, those with a past history of PONVor motion sickness and the administration of opiates. Thetype of surgery is also important: abdominal and laparo-scopic surgery are associated with a higher incidence.Volatile anaesthetic agents may cause early PONVwhereas propofol may be mildly anti emetic. Avoidance ofopioid analgesia should be considered for those at risk fromPONV.


A variety of drugs is available for prophylaxis and treat-ment. These act at different receptor sites and a combina-tion of agents may be considered appropriate in high riskpatients. Agents available include the phenothiazines (e.g.prochlorperazine), the butyrophenones (e.g. droperidol),antihistamines (e.g. cyclizine), 5-hydroxytryptamine antag-onists (e.g. ondansetron) and dexamethasone. Significantside effects may occur with some of these agents.Metoclopramide has limited efficacy for PONV. Thereis good evidence that acupuncture may also be a usefultreatment modality.

COLORECTAL SURGERY AND NUTRITIONMalnutritionMalnutrition is common on admission to hospital (Corishet al, 2004), particularly in elderly surgical patients(Rosenthal, 2004) and is associated with adverse outcomesin surgery. Windsor and Hill (1988) assessed weight loss in102 patients before major surgery and assigned each patientto one of three groups: group I (n = 43) were normal, groupII (n = 17) had weight loss greater than 10% but no clinicalevidence of physiologic impairment, and group III (n = 42)had weight loss greater than 10% with clear evidence of dys-function of two or more organ systems. The patients ingroup III had significantly more postoperative complications(P < 0.05), more septic complications (P < 0.02) includinga higher incidence of pneumonia (P < 0.05) and a longerhospital stay (P < 0.05) than patients in each of the othertwo groups. Colorectal patients with inflammatory boweldisease and colorectal neoplasia are particularly at risk ofperioperative malnutrition. De la Hunt (1984) specificallyidentified colorectal patients at high risk of postoperativecomplications especially sepsis and breakdown of anasto-moses and wounds. Using anthropometric measurements:of 30 recorded major postoperative complications, 72% wereseen in patients with low body weight, 69% with low fore-arm muscle circumference, 55% with recent weight loss,and 57% with serum albumin below 35 g/L.

AssessmentsIn the acute-care setting (Huckleberry, 2004), history ofweight loss from the patient, relatives or care-giver is thebasis of most nutritional assessments. As a rule of thumb,patients weighing less than 70% of their ideal weight orless than 80% of their usual weight are considered severelymalnourished. However, the accuracy of determiningweight loss by history alone has been questioned(Jeejeebhoy, 2000): 33% of patients with weight loss beingmissed and 25% of those with stable weight being wronglydiagnosed as having lost weight. Aspects of physical exam-ination may also be useful (Hammond, 1999) in assessingnutritional status. Anthropometry includes triceps andsubscapular skinfold thicknesses, which provides an indexof body fat, and mid-arm muscle circumference, whichgives a measure of muscle mass. Although these meas-urements seem to be useful in population studies, their reli-ability in individual patients is less clear (Jeejeebhoy, 2000).

A valuable tool of bedside nutritional assessment is thetechnique of subjective global assessment (SGA; Jeejeebhoy,2000). The history used in the SGA determines:

● Percentage of body weight lost in the previous 6 months:mild (< 5%), moderate (5–10%), and severe (> 10%).

● Dietary intake: normal or abnormal as judged by a changein intake and whether the current diet is nutritionally ade-quate.

● Presence of persistent gastrointestinal symptoms such asanorexia, nausea, vomiting, diarrhoea, and abdominalpain, which have occurred almost daily for at least2 weeks, is recorded.

● Functional capacity: defined as bedridden, suboptimallyactive or full capacity.

● Metabolic demands of the patient’s underlying diseasestate: high-stress illnesses are burns, major trauma andsevere inflammation such as acute colitis; moderate-stressdiseases might be a mild infection or limited malignancy.

Physical examination includes assessing:

● Loss of subcutaneous fat is measured in the triceps regionand the midaxillary line at the level of the lower ribs.

● Muscle wasting in the temporal areas and in the deltoidsand quadriceps, as determined by loss of bulk and tonedetectable by palpation.

● Presence of oedema in the ankle and sacral regionsand/or the presence of ascites.

● Mucosal and cutaneous lesions are recorded, and thecolour and appearance of the patient’s hair.

The findings of the history and physical examination areused to categorise patients as being well nourished, havingmoderate or suspected malnutrition, or having severemalnutrition (Table 3.28).

Malnutrition as measured by subjective global assess-ment is associated with postoperative complications aftermajor abdominal surgery (Sungurtekin et al, 2004). Guptaet al (2005) examined the prognostic significance of SGAin patients with advanced colorectal cancer. The prevalenceof malnutrition in this patient population, as determinedby SGA, was 52% (113/217). The median survival ofpatients with SGA A was 12.8 months (95% CI 9.1–16.5),those with SGA B was 8.8 months (95% CI 6.7–10.9) andthose with SGA C was 6 months (95% CI 3.9–8.1); the dif-ference being statistically significant (P = 0.0013). In addi-tion to being a clinically useful tool, SGA is a clinicaltechnique that can be rapidly taught to medical personnel(Duerksen, 2002) (Table 3.29).

Visceral proteinsLow serum albumin correlates with an increased inci-dence of medical and surgical complications. Kudsk et al(2003) performed a retrospective study of 526 surgicalpatients who had preoperative serum albumin levelsmeasured and underwent elective oesophageal, gastric,pancreaticoduodenal or colon surgery between 1992and 1996 and did not receive preoperative nutrition.Preoperative albumin correlated inversely with complica-tions (Table 3.30), length of stay, postoperative stay, ICUstay, mortality, and resumption of oral intake. Patientsundergoing oesophageal or pancreatic procedures sus-tained a significantly higher complication rate at mostalbumin levels, whereas colonic surgery resulted in lowercomplication rates at the same albumin levels.

Risk Management 115

Although albumin concentration correlates with out-comes it is not a good indicator of nutritional status per se(Jeejeebhoy, 2000). This is because several processes con-trol plasma albumin concentration, including the absoluterate of albumin synthesis, the fractional catabolic rate(FCR), albumin distribution between the vascular andextravascular compartments, and exogenous loss of albu-min. Thus the rate of albumin synthesis is affected by bothnutrition and inflammation, given that albumin is a neg-ative acute-phase protein (Don and Kaysen, 2004).Prealbumin has been proposed as a visceral protein thatis responsive to nutritional changes. However, it is alsoinfluenced by several disease-related factors, making itunreliable as an index of nutritional status in patients(Jeejeebhoy, 2000).

Perioperative enteral nutritionDeliveryFor the large majority of hospital patients, enteral nutri-tion means hospital food. Unfortunately, eating in hospitalcan be difficult for some patients. This can be attributed tothe disruption of sociocultural, psychological and physio-logical factors that occurs as a result of illness and/or hos-pitalisation (Holmes, 2003). For example, admission tohospital may cause significant stress, markedly reducinginterest in food. Similarly, although it is known that eatingimproves when some control is exerted over the diet,patients can rarely influence either their food or times ofeating. There is an expectation that food will be poor and,in practice, the daily expenditure (Table 3.31) on food anddrink for UK hospital patients is remarkably modest (Audit


TABLE 3.28 CLASSIFICATION OF NUTRITION STATUS

Well nourished Moderately malnourished Severely malnourishedNo history of weight loss History of decreased dietary intake History of decreased dietary intakeNo change in dietary intake Weight loss (unintentional) of 5% to Weight loss (unintentional) > 10% of usual body No physical findings 10% of usual body weight weight

associated with Mild signs of malnutrition on Severe signs of malnutrition on physical malnutrition physical examination: examination:

Improving findings of ● Loss of subcutaneous fat ● Loss of subcutaneous fatmalnutrition (recent ● Muscle wasting ● Muscle wastingweight gain)

After Duerksen (2002).

TABLE 3.29 SUBJECTIVE GLOBAL ASSESSMENT OF MALNUTRITIONCORRELATED WITH IDEAL/USUAL BODY WEIGHT AND BMI

SGA % ideal % usual Malnutrition body weight body weight BMI kg/m2

Mild 80–90% 90–95% 17–18.5Moderate 70–79% 80–89% 16–17Severe < 70% < 80% < 16

After Salvino et al (2004) and Huckleberry (2004).

BMI, body mass index.

TABLE 3.30 INCIDENCE OF MAJOR COMPLICATIONS BY PREOPERATIVE ALBUMIN LEVEL ANDSITE OF SURGERY

Albumin level

Site of complication n 17.5 17.6–22.5 22.6–27.5 27.6–32.5 32.6–37.5 37.6–42.5 > 42.5Oesophagus 59 1/1 — 2/4 5/11 6/13 6/25 1/5Stomach 140 3/4 3/6 4/16 8/27 6/33 7/46 2/8Pancreas 106 1/1 3/4 8/11 8/17 6/32 4/30 1/11Colon 221 2/7 6/14 4/19 7/40 9/54 2/68 0/19Total 526 7/13 (54%) 12/24 (50%) 18/50 (36%) 28/95 (29%) 27/132 (20%) 19/169 (11%) 4/43 (9%)

After Kudsk et al (2003).

Commission, 2001). Fulham (2004) has suggested that asnack box should be made available to patients undergoingcolorectal and stoma surgery once oral intake is resumed(containing yoghurt, bananas, digestive biscuits, cheeseand crackers). In addition, verbal and written dietaryadvice should be provided for patients with new stomas,those undergoing stoma reversal and those having resectionwithout stoma formation.

Formal oral nutritional supplementation can be an effec-tive intervention in colorectal patients (Smedley et al,2004). Keele et al (1997) randomised principally colorec-tal cancer surgical patients to receive either a normal warddiet postoperatively, or the same diet supplemented with anoral dietary supplement. During the inpatient phase,patients treated with oral supplements had a significantlyimproved nutritional intake and lost less weight (2.2 kg;95% CI 0.9 kg) than control patients (4.2 kg; 95% CI 0.78kg; P < 0.001). Supplemented patients maintained theirhand grip strength whereas control patients showed asignificant reduction in grip strength (P < 0.01). Subjectivelevels of fatigue increased significantly above preopera-tive levels in control patients (P < 0.01) but not in thesupplemented group. Twelve patients in the control groupdeveloped complications compared with four in thesupplemented group (P < 0.05). Thus, merely raisingnutritional intakes with oral dietary supplements or earlypostoperative enteral feeding appears to be sufficient tomaintain immune and muscle function in patientsundergoing elective lower gastrointestinal surgery (Silk,2003). In addition, enteral nutrition is associated with aspecific therapeutic effect in Crohn’s disease. Gassull et al(2002) record that three meta-analyses of RCTs compar-ing steroids and enteral nutrition in the treatment of activeCrohn’s disease show that although steroids are moreeffective, the overall remission rate by intention-to-treatafter enteral nutrition is 60%, substantially higher thanthe placebo response in trials evaluating other drugs forCrohn’s disease.

Short-term delivery systems for enteral nutrition includenasogastric (NG; 14 to 16 French), nasoduodenal andnasojejunal tubes (Nisim and Allins, 2005). These systemsavoid a surgical procedure but are probably only useful forshort-term (< 6 weeks) nutrition. The length of tube

required is gauged by measuring the distance from the noseto an earlobe and then to the xiphoid process. Appropriateplacement of nasoenteric tubes can be confirmed by aus-cultation over the epigastrium or the left upper quadrantof the abdomen while insufflating air (50 mL) down thetube. However, this auscultation technique can be unreli-able and a postinsertion X-ray should be taken to confirmplacement of the tube (Williams and Leslie, 2004; Nisimand Allins, 2005). To minimise the risk of aspiration, thehead of the bed must be elevated to 30 to 45 degrees. Thenasoenteric tube should be flushed with water after beingused to administer medication.

The assumption that nasojejunal tubes are superior tonasogastric feeding with regard to avoiding aspiration hasbeen challenged. Strong et al (1992) compared chest X raysfrom 17 stomach-fed patients with 16 patients fed post-pylorus. Chest radiographs met the criteria for aspirationpneumonia in 31.3% of gastric and 40% of postpylorus-fed patients (P = NS). Together, these data indicate thatcomplications from enterally fed patients are equally com-mon whether the distal port of the feeding tube is in thestomach or beyond the second portion of the duodenum.Similarly, in a critical care setting Neumann and DeLegge(2002) found no increase in aspiration and other adverseoutcomes when the nasogastric route was compared withnasal-small-bowel feeding tubes. Moreover, patients fed inthe stomach received nutrition sooner from initial place-ment attempt (11.2 hours versus 27.0 hours) and withfewer attempts (one versus two) than those fed in the smallbowel. Patients achieve feeding goals sooner (28.8 hoursversus 43.0 hours) with gastric feeding compared withsmall-bowel feeding. Eatock et al (2005) also reported thatenteral nutrition of patients with acute pancreatitis wascheaper and easier with nasogastric feeding compared tonasojejunal feeding.

The goal of enteral feeding (Nisim and Allins, 2005)is to approximate normal nutrient consumption in anindividual. As such, intermittent bolus feedings (12–16hours in each 24-hour period) are typically implemented.The rate of administration is determined by infusing intothe stomach a volume of water that is equivalent to thedesired hourly feeding volume. This should be done grad-ually over 1 hour to avoid acute gastric distension, whichcan lead to overestimation of the residual volume. At theend of the hour, the feeding tube should be clamped for30 minutes. The residual volume is then checked byunclamping the feeding tube and aspirating any remain-ing fluid. One can initiate tube feedings if the residualsare less than 50% of the infused volume.

Longer-term delivery systems (Culkin and Gabe, 2002;Dormann and Huchzermeyer, 2002; Gopalan and Khanna,2003; Nisim and Allins, 2005) include percutaneous endo-scopic gastrostomy (Holmes, 2004), percutaneous endo-scopic jejunostomy, needle catheter jejunostomy, operativegastrostomy, which can be temporary (e.g. Stam’s tech-nique) or permanent (e.g. Janeway’s technique) and openor laparoscopic jejunostomy. Infection of the tube insertionsite can be a source of patient morbidity. MRSA infectionof gastrostomy and jejunostomy sites may be reduced by astrategy consisting of screening, skin decontamination andglycopeptide prophylaxis (Rao et al, 2004). Once these

Risk Management 117

TABLE 3.31 NET EXPENDITURE ON FOODAND BEVERAGES PER PATIENT DAY

Location of Total net expenditure Hospital Trust per patient day

Outside LondonSmall Trust £6.56Medium-sized Trust £5.91Large Trust £5.46

London£7.64

From Audit Commission (2001).

tubes become colonised by MRSA, eradication is usuallyonly achieved either by removing the tube altogether or ifneeded long term by replacement under vancomycin cover.McClave and Chang (2003) provide an overview ofcomplications associated with enteric feeding devices(Table 3.32).

Laparoscopic gastrostomy was compared with open gas-trostomy insertion by Murayama et al (1995). Operativetime was significantly shorter in the laparoscopic gastros-tomy group (38 ± 7 min) than in the open gastrostomygroup (62 ± 19; P < 0.0001. Major complication rate forlaparoscopic gastrostomy was 6% and for open gastrostomywas 11%. The authors concluded that laparoscopic gas-trostomy was a safe and effective alternative to open gas-trostomy, particularly in patients unable to undergo upperendoscopy or in patients undergoing a concomitant laparo-scopic procedure. Hotokezaka et al (1996) reviewed laparo-scopic jejunostomy in 32 patients. Laparoscopic insertionwas successfully completed in 28 patients but the procedurewas converted to an open operation in four cases. Three ofthese four were among 14 patients undergoing the proce-dure who had a history of previous abdominal surgery.Major complications were observed in seven patients,including one reoperation and one death from aspirationpneumonia. Tube feeding was accomplished in all patientswith progression to a full enteral feeding proceeded with-out interruption in 20 patients. There is a risk of faecal tubefeed peritonitis in malnourished patients who leak from thejunction between the enterotomy and abdominal wall.

CompositionThe carbohydrate content of a given feeding formula is theprimary source of calories. Most formulas contain 1 to 2kcal/L. Carbohydrates are also the major determinants ofa formula’s osmolality, which typically varies from 280 to100 mOsm/kg of H2O. Protein contents of common liquidfeeding formulas range from 35 to 40 g/L. Patients whohave conditions that result in impaired intestinal absorp-tion (e.g. inflammatory bowel disease) often benefit fromformulas with enhanced absorption properties. Small pep-tides tend to be better absorbed by the intestinal mucosa

than amino acids, hence these patients often receive pep-tide-based formulas. Lipids provide a concentrated sourceof calories in the form of long-chain triacylglycerols derivedfrom vegetable oils. They are high-energy compounds thatcontain approximately three times the amount of caloriesas carbohydrates (9 kcal/g versus 3.4 kcal/g, respectively).Typically, the total lipid content in formulas is limited to30% of the total volume. A host of enteral formulas exist.Table 3.33 lists important features that can be used for theselection and administration of enteral feeding products(Lipman, 2004).

Immunonutrients are defined as nutrients that pro-vide specific benefits to the immune system, and includeglutamine, arginine, long-chain n-3 polyunsaturated fattyacids (PUFAs) and nucleotides (Moskovitz and Kim,2004):

● Glutamine is a precursor for the synthesis of other aminoacids, purines and pyrimidines. It serves as an impor-tant nutrient for many cell types, including small intes-tine enterocytes, colonocytes and fibroblasts. Muscleis the chief supplier, containing 60% of the total, free glu-tamine in the body. Limiting the supply of glutamine tothe immune system results in reduced capability of thehost to fight infection.

● Arginine is a precursor for the synthesis of nitric oxide. Itis a dietary non-essential amino acid. Arginine levels arereduced in stress states as a result of inadequate endoge-nous synthesis. Supplementation with arginine has beenshown to have beneficial effects on the immune responseby improving the response of peripheral blood cells tomitogen, enhancing natural killer cell activity, andincreasing lymphokine-activated natural killer cellpopulations.

● Eicosapentaenoic acid (EPA) and PUFAs enhance the pro-duction of prostaglandin E-3 and decrease the productionof prostaglandin E-2. EPA and PUFAs have a major impacton the function of many components of the immunesystem. PUFAs exert their effect on membrane lipidcomposition, the binding of cytokines, the formation ofmembrane-generated cellular signals, and effects on geneexpression.


TABLE 3.32 COMPLICATIONS ASSOCIATED WITH ENTERIC FEEDINGDEVICES

Nasoeneteric tube PEGProcedure Epistaxis 1.8–4.7% Aspiration 0.3–1%

Aspiration 0–1.8% Haemorrhage 1%Other viscous injury 0.5–1.8%Transient pneumoperitoneum 40–56%Prolonged ileus 3%

Specific Migration 12.5–16% Site infection 5.4–30%Dislodgement 25–41% Excessive leakage 1–2%Tube breakage 11–20% Buried bumper up to 21.8%Tube occlusion 9–20% GI bleeding 0.6–1.2%

Inadvertent extubation 1.6–4.4%

After McClave and Chang (2003).

GI, gastrointestinal; PEG, percutaneous endoscopic gastrostomy.

Grimble (2005) describes a ‘transcriptional focus’ as thebasis of immunonutrition. Thus oxidant molecules upreg-ulate cytokines, other inflammatory mediators, adhesionmolecules and enzymes associated with antioxidantdefence through the activation of nuclear transcriptionfactors such as nuclear factor kappa B (NFκB) and acti-vator protein-1 (AP-1). Both antioxidants and the omega-3 fatty acid, EPA, prevent NFκB from activation, theformer substances by reducing oxidative stress in the celland the latter by stabilisation of the transcription factorcomplex.

Heys et al (1999) conducted a meta-analysis of 11 RCTs(published in peer-reviewed journals) evaluating the use ofenteral nutritional support supplemented with combina-tions of key nutrients versus standard enteral nutrition, ina total of 1009 patients with a critical illness. The keynutrients used in the various combinations were L-arginine,L-glutamine, branched-chain amino acids, essential fattyacids and RNA. Although there was no reduction in patientdeath, the analysis did reveal:

● Significant reduction in the overall OR for the risks ofdeveloping major (pneumonia, intra-abdominal abscess,major wound infections, septicaemia) infectious compli-cations (OR 0.47; 95% CI 0.32–0.70).

● Significant reduction in hospital stay for patients receiv-ing targeted nutrition. This was a reduction of 2.5 days(95% CI 4.0–1.0 days; chi square test for heterogeneity4.73; P = NS).

A similar, more recent meta-analysis (Montejo et al, 2003)examined randomised clinical trials of critically ill patientstreated with enteral nutrition comparing diets enrichedwith pharmaconutrients with non enriched enteral diets.Infectious complications and outcome variables (days onmechanical ventilation, ICU and hospital length of stay andmortality) were evaluated. Global results from 26 relevantprimary studies indicated that immunonutrition regimensare associated with:

● a reduction in infection rate: lower incidence of abdomi-nal abscesses (OR 0.26; 95% CI 0.12–0.55; P = 0.005),nosocomial pneumonia (OR 0.54; 95% CI 0.35–0.84;P = 0.007) and bacteraemia (OR 0.45; 95% CI0.35–0.84; P = 0.0002)

● a reduction in time on mechanical ventilation (mean 2.25days; 95% CI 0.5–3.9; P = 0.009), ICU length of stay(mean reduction of 1.6 days, CI: 1.9-1.2) (P < 0.0001)and hospital length of stay (mean reduction of 3.4 days;95% CI 4.0–2.7; P < 0.0001)

● no effect on mortality (OR 1.10; 95% CI 0.85–1.42;P = 0.5).

On this basis, Montejo et al (2003) concluded that the evi-dence supported a grade B recommendation for the use ofimmunonutrient enteral feed in ICU patients.

Garcia-de-Lorenzo et al (2003) described glutamine-enriched diets as being associated with good overall tolerance,improvement of immunologic aspects in multiple traumapatients, cost reduction in critically ill patients and improve-ment of mucositis in postchemotherapy patients (grade Brecommendations). However, several studies reviewed byHeyland and Samis (2003), with the exception of Galbanet al (2000), indicated that septic critical care patients ran-domised to immunonutrition fared less well than patientsreceiving standard enteral nutrition or parenteral nutri-tion (Table 3.34). Thus, Bertolini et al (2003) studied 237patients randomised by 33 ICUs between November 1999and April 2001, 39 of whom had severe sepsis. Of these 39patients with severe sepsis, 21 were randomised to receiveeither TPN (59% carbohydrate, 23% fat, 18% protein,1.2 kcal/mL) and 18 were randomised to an enteral nutri-tion formula that included L-arginine, omega-3 fatty acids,vitamin E, beta carotene, zinc and selenium (55% carbo-hydrate, 25% fat, 21% protein, 1.3 kcal/mL). The ICU mor-tality of the group receiving the enteral immunonutrients(44%) was significantly higher than the group assignedparenteral nutrition (14%). Heyland and Samis (2003)speculate that the immune-modulating nutrient (or com-bination of nutrients) responsible for the excess harmobserved, in septic patients in these studies is probably argi-nine. Arginine supplementation is capable of promoting anincrease in nitric oxide production, which may havean adverse effect on critically ill patients with sepsis.Heyland and Samis (2003) therefore recommend morestudy of arginine supplementation before it is routinelyincorporated into immunonutrient regimens.

Kieft et al (2005) conducted the largest randomised,controlled trial of immunonutrition in a general ICU

Risk Management 119

TABLE 3.33 CONSIDERATIONS IN ENTERAL NUTRITION FORMULA COMPOSITION

Water Origin Macronutrient content Added substrates Disease specificSufficient Blenderised Intact protein vs amino Soluble fibre Liver

free water whole food acids and/or peptides ‘Immune-enhancing’ Pulmonary(1 kcal/cc vs defined Complex carbohydrates nutrients: omega-3 Renalformulas) vs nutrient vs simple sugars fatty acids, RNA, Diabetesconcentrated substrates ‘Normal’ fat content arginine, ± glutamine Critical careformulas with vs reduced fat ± Modules of protein, free water medium-chain carbohydrate or fat removed triglycerides can be added before

Lactose-free administration to increase protein or energy content

From Lipman (2004).

population. The control group comprised 140 surgical, 16trauma and 83 medical patients; the immunonutritiongroup was composed of 113, 23 and 95 patients, respectively.The study formula (immunonutrition) was a high-proteinenteral tube feed enriched with glutamine, arginine, 3-FA,antioxidants and a mixture of fibres (Stresson Multi Fibre®,Nutricia, the Netherlands). The control feed was anisocaloric enteral formula to prevent the groups receivingdifferent amounts of energy. Results of the intention-to-treat analysis in control versus immunonutrition were:median ICU length of stay in days, 8.0 (IQR 5.0–16.0)versus 7.0 (4.0–14.0); median hospital length of stay indays, 20.0 (IQR 10.0–34.0) versus 20.0 (10.0–35.0);median days of ventilation, 6.0 (IQR 3.0–12.0) versus 6.0(IQR 3.0–12.0); ICU mortality, 26.8% versus 28.2%; in-hospital mortality, 36.4% versus 38.5%; infectiouscomplications, 41.7% versus 43.0%. Thus, immunonutri-tion has no beneficial effect on clinical outcome parametersin the general ICU population. Heyland and Dhaliwal(2005) concluded that the current approach to definingthose key nutrients that may have positive effects in criticallyill patients is not working. A new paradigm should focuson single nutrients dissociated from nutrition, tested inhomogenous patient populations in large, rigorouslydesigned randomised clinical trials.

Perioperative parenteral nutritionThe Veterans Affairs Total Parenteral Nutrition CooperativeStudy Group (1991) studied 395 malnourished patientswho required laparotomy or non-cardiac thoracotomy andrandomly assigned them to receive either TPN for 7–15days before surgery and 3 days afterward (the TPN group)or no perioperative TPN (the control group). The patientswere monitored for complications for 90 days after surgery.Major complications during the first 30 days after surgeryin the two groups were similar (TPN group 25.5%; controlgroup 24.6%), as were the overall 90-day mortality rates(13.4% and 10.5%, respectively). Although the TPN grouphad more infectious complications than in the controls(14.1 versus 6.4%; P = 0.01; relative risk, 2.20; 95% CI,1.19–4.05), this increase was confined to patients cate-gorised as either borderline or mildly malnourished,according to SGA or an objective nutritional assessment.By contrast, severely malnourished patients who receivedTPN had fewer non-infectious complications than controls(5 versus 43%; P = 0.03; relative risk, 0.12; 95% CI,0.02–0.91), with no concomitant increase in infectious

complications. The authors concluded that the use of pre-operative TPN should be limited to patients who areseverely malnourished unless there are other specificindications.

Heyland et al (2001) conducted a meta-analysis of 27papers that met their inclusion criteria. Overall, 2907patients were randomised to comparisons of TPN againststandard care (oral diet or intravenous dextrose solution).Aggregation of the results of these trials showed no effecton mortality (RR = 0.97; 95% CI 0.75–1.24). However,TPN was associated with a reduction in complication rates(RR = 0.081; 95% CI 0.65–1.01, P = 0.06). Comparisonwas made between trials that only included malnourishedpatients with the other available trials. TPN was again notassociated with any difference in mortality in either studiesof malnourished or normally nourished patients. However,TPN was associated with a significant reduction in compli-cation rates in the trials that contained overtly malnour-ished patients (RR = 0.52; 95% CI 0.30–0.91). The authors(Heyland et al, 2001) concluded that although methodol-ogy and year of publication might influence the meta-analysis findings, TPN appears to reduce the complicationrate in surgical patients but not the death rate of this group.

Nehra et al (1999) described their indications for par-enteral nutrition in 100 consecutive patients. Characteristicsof this patient population included mean weight (118 ±29% of ideal), body mass index (25 ± 6 kg/m2) and serumalbumin (28 ± 7 g/L). The most common specific reasonsidentified for initiating TPN rather than enteral nutritionwere ileus (25%), an underlying acid–base or electrolyte/mineral disorder requiring correction (13%) and the con-venience of TPN because a central venous catheter was inplace (12%). Jones (2003) describes three clinical patternsof intestinal failure which may require parenteral support:

● Type 1: short-term intestinal failure as after abdominalsurgery when intestinal failure is self limiting.

● Type 2: intestinal failure in severely-ill patients with majorresections of bowel and septic, metabolic and nutritionalcomplications requiring complex multidisciplinary inter-vention with metabolic and nutritional support to permitrecovery.

● Type 3: chronic intestinal failure requiring long-termnutritional support.

In most colorectal surgical practice parenteral support isseen most commonly in type 1 patients and occasionallyin type 2 patients.


TABLE 3.34 IMMUNONUTRIENTS AND MORTALITY OF SEPTIC PATIENTS IN CRITICAL CARE

Control group Experimental P valueBower et al, 1995 4/45 (8.9%), 11/44 (25%) 0.051 ImpactDent et al, 2003 8/83 (9.6%) 20/87 (23%) 0.03 L-arginine, omega-3 fatty acids,

vitamins A and E, beta caroteneGalban et al, 2000 28/87 (32.2%) 17/89 (19.1%0 0.05 ImpactBertolini et al, 2003 3/21 (14.3%) 8/18 (44.4%) 0.039 L-arginine, omega-3 fatty acids, vitamin E,

(severe sepsis beta carotene, zinc, seleniumsubgroup)

After Heyland and Samis (2003).

Complications of parenteral nutritionBloodstream infections are a common complication ofimplanted venous access catheters. This is a troublesomecomplication of short term total parenteral nutrition (TPN)which can be fatal unless promptly treated. However, thesepsis and lack of venous access from repeatedly changingvenous access catheters is the issue which determines lifeexpectancy in home parenteral nutrition (HPN). Tay et al(2002) audited 50 patients in a surgical intensive care unitand found that hyperglycaemia and line sepsis increasedwith duration of TPN use. Moore et al (2004), in a retro-spective survey of home parenteral nutrition patients,describe a higher catheter infection rate with PICC lines(458 per 100 catheter days) than with central venouscatheters (285 per 100 catheter days; P < 0.01). Surveysof hospital-acquired bacteraemias and septicaemias in theUS have shown that during 1986–9, coagulase-negativestaphylococci, followed by Staph. aureus, were the most fre-quently reported causes of bloodstream infections,accounting for 27% and 16%, respectively, but that pooleddata from 1992 to 1999 indicate that coagulase-negativestaphylococci, followed by enterococci, are now the mostfrequently isolated causes of hospital-acquired bloodstreaminfections (O’Grady et al, 2002). The authors recommendthat strategies to reduce central-line sepsis might include:

● educating and training health-care providers who insertand maintain catheters

● using maximal sterile barrier precautions during centralvenous catheter insertion

● using a 2% chlorhexidine preparation for skin antisepsis● avoiding routine replacement of central venous catheters

as a strategy to prevent infection.

Endocarditis is a particularly feared complication of cen-tral-line access and may require repeated echocardiogra-phy (Leinhardt et al, 1992) to confirm the diagnosis.Fungal as well as bacterial infection may be implicated inthe valvular lesions (Schelenz and Gransden, 2003).

Sutton et al (2005) introduced a clinical nurse special-ist to maintain protocol standards for parenteral nutritionvenous catheters. The protocols included care of the exitsite (exit site from the subcutaneous tunnel), sprayed withBetadine Powder Spray (Seton Healthcare plc, UK), dressedwith Mepore™ (Smith and Nephew plc, UK) and coveredwith an Opsite™ dressing (Smith and Nephew plc, UK) andthe use of designated nursing staff to commence TPN infu-sions. Designated nurses were required to attend a studyday and pass a practical assessment dealing with aseptic

procedures and TPN catheters. This innovation bothreduced the infection rate of central venous catheters(Table 3.35) and paid for the cost of employing the clinicalnurse specialist by savings in wasted central venouscatheters, TPN and operating time.

Hepatobiliary dysfunction (Porayko, 1998) is associatedwith the use of TPN occurring in up to 90% of patients onlong-term therapy. Luman and Shaffer (2002) described 51patients (47.7%) with deranged liver function tests (LFT).The abnormality in LFT was transient in nine patients. Forthe other 42 patients (39%), abnormalities in LFT remainedstable for median duration of follow-up of 18.5 (range3–180) months. No patients developed decompensated liverdisease. On univariate analysis, length of small bowel of lessthan 100 cm, a higher total caloric intake from HPN (homeparenteral nutrition) (mean 1117 ± 486 kcal against 907± 576 kcal, P < 0.05), and higher daily caloric intake fromHPN in relation to calculated daily energy requirement(70 ± 32% against 57 ± 36%) were noted to be significantlyassociated with deranged LFT. However, on multivariateanalysis, length of small bowel of less than 100 cm was theonly significant variable for deranged LFT.

Instituting surgical nutritionThere are three basic steps in providing perioperativesurgical nutrition:

1. Does the patient require nutritional support?2. Which route(s)—enteral or parenteral—should be

used?3. Are the goals of nutritional support being achieved?

Malnourished patients are at greater risk for perioperativeand postoperative morbidity and mortality than well-nourished patients (Salvino et al, 2004). Preoperativenutritional support should be considered for severely mal-nourished patients if their elective surgery can be delayedfor this period of time. Postoperatively, nutritional supportshould be considered if it is anticipated that a patient willbe unable to eat within 7 to 10 days of surgery (Salvinoet al, 2004).

If perioperative nutritional support is required, whichis the best route—enteral or parenteral? The followingrecommendations are based on ASPEN guidelines:

● Moderately to severely malnourished patients scheduledfor major gastrointestinal surgery should receive 7–14days of preoperative nutritional support if surgery can besafely postponed.

Risk Management 121

TABLE 3.35 CATHETER-RELATED SEPSIS BEFORE (YEAR 0) AND AFTER INTRODUCTION OFNUTRITION VIA CENTRAL VENOUS CATHETER IN PATIENTS ON HPN

Year 0 Year 1 Year 2 Year 3 Year 4 (n = 56) (n = 54) (n = 49) (n = 34) (n = 40)

Definite sepsis (%) 5.2 3.7 2 2.9 2.3Probable sepsis (%) — 9.2 4 0 0Possible sepsis (%) — 5.5 4 0 0

After Sutton et al (2005). HPN, Home parenteral nutrition.

● Parenteral nutrition should not be routinely prescribedin the immediate postoperative period for patientsundergoing major gastrointestinal surgery.

● Postoperative nutritional support is warranted if inade-quate oral nutrition is anticipated for 7–10 days.

Heyland et al (2003) carried out a systematic analysis ofcontrolled clinical trials of nutrition in ICU patients. Themajor findings of the analysis were:

● Increased infectious complications for parenteral nutri-tion reported in six trials for which the relative risk forenteral nutrition was 0.61. By contrast, there was nosignificant difference in mortality or in length of stay.

● Early enteral nutrition showed a trend toward reducedmortality or infectious complications without statisticalsignificance.

● Arginine supplementation in enteral nutrition did notinfluence mortality or infections.

● Glutamine supplementation resulted in heterogeneousfindings with reduced complications in some, but notother, studies.

● Enteral nutrition in the semirecumbent position signif-icantly reduced the incidence of pneumonia in onestudy.

The findings of reduced infectious complications withenteral nutrition but no advantage in overall patientmortality have been repeatedly reported in other systematiccomparisons. Braunschweig et al (2001) systematicallyreviewed the results of prospective randomised clinicaltrials to examine the relations among the nutrition inter-ventions, complications and mortality rates. Aggregatedresults from 27 studies involving 1828 patients showed asignificantly lower relative risk of infection with tube feed-ing (0.64; 95% CI 0.54–0.76) and standard care (0.77;95% CI 0.65–0.91). However, in studies in which partici-pants had high rates of protein-energy malnutrition, therewas a significantly higher risk of mortality (3.0; 95% CI10.9–8.56) and a trend towards a higher risk of infectionwith standard care than with parenteral nutrition (1.17;95% CI 0.88–1.56). Gramlich et al (2004), from a meta-analysis of 13 studies, found that the use of enteral nutri-tion as opposed to parenteral nutrition was associated witha significant decrease in infectious complications (RR =0.64; 95% CI = 0.47–0.87; P = 0.004) but made no dif-ference to mortality rate (RR = 1.08; 95% CI = 0.70–1.65;P = 0.7). Peter et al (2005) examined 30 RCTs (10 medical,11 surgical, 9 trauma) to compare the impact of earlyenteral nutrition with parenteral nutrition on patientoutcomes. There was no differential treatment effectof nutrition type on hospital mortality for all patients(0.6%; P = 0.4) and subgroups. Parenteral nutrition wasassociated with increases in infective complications (7.9%;P = 0.001), catheter-related bloodstream infections (3.5%;P = 0.003), non-infective complications (4.9%; P = 0.04)and hospital LOS (1.2 days; P = 0.004). There was noeffect of nutrition type on technical complications (4.1%;P = 0.2). Enteral nutrition was associated with a signifi-cant increase in diarrhoeal episodes (8.7%; P = 0.001).

If enteral nutrition is associated with no improvementin mortality but is associated with a reduced rate of infec-

tious complications, does it have any drawbacks? The majordrawback of enteral nutrition in a critical-care populationis that the nutritional support can be inadequate. Onestudy of patients in a multidisciplinary ICU populationrevealed that only 56% of goal caloric requirements weremet by enteral nutrition (Sigalet et al, 2004). Underfeedinghas been ascribed to gut dysfunction and elective cessationof enteric feeding. Moreover, there does not appear to beany advantage to combining enteral and parenteral nutri-tion in critically ill patients who are not malnourished andhave an intact gastrointestinal tract. Dhaliwal et al (2004)examined studies of enteral nutrition alone against com-binations of enteral and parenteral nutrition. When thefive identified studies were aggregated, meta-analysisshowed that the use of combination enteral and parenteralnutrition had no effect on mortality (RR 1.27; 95% CI0.82–1.94; P = 0.3).

In essence, there is no dichotomy in the use of par-enteral or enteral nutrition. Although parenteral nutritionis associated with more septic complications, it does pro-vide a reliable means of delivering protein, energy, elec-trolytes and vitamins (Sigalet et al, 2004). Moreover,parenteral nutrition has been shown to be associated withimproved survival in malnourished surgical patients whencompared to standard care.

The composition of all nutritional support is aimed atdelivering the correct requirements of water, electrolytes,calories (carbohydrate and fat), protein, vitamins andmicronutrients. Total energy requirement is usually deliv-ered as a mixture of glucose and lipid in a ratio of 60 : 40.However, significant glucose intolerance or the require-ment for fat free parenteral nutrition would need to befactored into the individual patient’s regimen.

A patient’s energy requirements (basal metabolic rate;BMR) can be estimated from equations such as theSchofield or Harris–Benedict equation (Bauer et al, 2004)(Table 3.36). In turn, the estimated BMR can be increasedby a ‘stress factor’ associated with the degree of systemicinsult—perhaps 5–20% by uncomplicated surgery and25–40% in complicated surgery using published nomo-grams (Reeves and Capra, 2003). However, among ‘stressfactor’ estimates identified, including the Elia nomogram,the evidence base for the estimates is less than robust.

The accuracy and agreement of estimated BMR is alsofar from perfect (Bauer et al, 2004). McClave et al (1998)found that, compared with indirect calorimetery measuredresting energy expenditure, nutritional regimens based onthe Harris–Benedict equation meant that underfeeding andoverfeeding were common, with only 25% of patientsreceiving calories within 10% of required needs. The res-piratory quotient (RQ = VCO2/VO2) has been proposed asa test to determine the adequacy of caloric support.Underfeeding, which promotes use of endogenous fatstores, should cause decreases in the RQ, whereas over-feeding, which results in lipogenesis, should cause increasesin the RQ. However, McClave et al (2003) concluded froma study of 263 enterally fed, mechanically ventilatedpatients that although changes in the overall and non-pro-tein RQ correlate to percentage calories provided/required,low sensitivity and specificity limit its efficacy as an indi-cator of over- or underfeeding. In our experience, the


typical surgical patient will require a 1800 kcal regimenwith an average daily requirement of 25 kcal/kg/day.Excess calories should be avoided as they can adverselyaffect liver function and lead to increased CO2 production.

For 95% of the normal population consuming an ade-quate energy intake, 0.8 g of protein/kg body weight isadequate (Bistrian and Babineau, 1998). Surgical insult ordisease leads to protein malnutrition by inducing anorexia,motor inactivity, protein anabolic inefficiency and anincrease in protein catabolism. Greater amounts of proteinthan the recommended dietary allowance are required toachieve protein sparing with increasing severity of the sys-temic inflammatory response syndrome, but further pro-tein sparing is difficult to achieve once 1.5 g of protein/kgbody weight is provided. This situation invariably leads tonet protein loss early in the illness of most critically illpatients (Bistrian and Babineau, 1998). Therefore, mostprotein replacement regimens consist of 1.2–2.0 g/kg/day(Huckleberry, 2004; Salvino et al, 2004). Protein providedin excess of this amount is converted to urea.

ENHANCED RECOVERY AFTERCOLORECTAL SURGERYOne of the major benefits of laparoscopic colorectal sur-gery has been the realisation that the time honoured prac-tice of postoperative starvation, morphine analgesia,delayed ambulation inhibits the speed of recovery follow-ing both open and minimal access colorectal surgery.Furthermore delayed feeding does not protect against anas-tomotic breakdown. The need for minimal analgesicrequirements and rapid recovery in laparoscopic surgeryhas influenced open surgical practice and the developmentof enhanced recovery policies (Wind et al, 2006). A groupof 60 consecutive patients scheduled for elective colonicresection (excluding planned low anterior resection andrectum extirpation, and patients undergoing surgery forinflammatory bowel disease) were studied in the context ofan accelerated rehabilitation program by Basse et al(2000). Features of the study design included:

● Patient informed by the research team of a planned 48-hour postoperative hospital stay.

● No premedication administered.● Thoracic epidural catheter inserted at T6–T7 for right

hemicolectomy and at T8–T10 for left-sided and sigmoidresection. After surgery, continuous epidural analgesiawith bupivacaine and morphine maintained for 48 hours.

● Right-sided hemicolectomy performed with a horizontalincision 2–3 cm above the umbilicus, resection of thetransverse colon with a transverse incision cephalad tothe umbilicus, and left-sided hemicolectomy and sigmoidresection with a curved incision in the left iliac fossaextended up toward the curvature when necessary. Allanastomoses hand-sewn.

● Gastrointestinal tubes not used.

Postoperative mobilisation and oral intake followed a well-defined nursing care program (Table 3.37).

The colonic resections (Basse et al, 2000) included 23right-sided hemicolectomies, two resections of the trans-verse colon, 34 sigmoid resections or left hemicolectomiesand one subtotal colectomy. Median duration of surgerywas 120 minutes (range 70–360). Median intraoperativeblood loss was 100 mL (range 50–2450 mL). Underlyingcolonic disease was cancer in 42 patients (Dukes’ A infour patients, Dukes’ B in 22, Dukes’ C in 11 and Dukes’D in five), lymphoma in one patient and benign colonicdiseases in 17 patients. Overall, normal gastrointestinalfunction (defecation) occurred within 48 hours in 57patients and the median hospital stay was 2 days. Therewere no cardiopulmonary complications. The readmis-sion rate was 15%, including two patients with anasto-motic dehiscence (one treated conservatively, one withcolostomy); other readmissions required only short-termobservation.

In a similar study, Delaney et al (2001) subjected 60 con-secutive patients [median age 44.5 (range 13–70) years]undergoing major procedures to a ‘fast track’ protocol (earlydiet and early ambulation; defined discharge criteria) overa 6-week period. Nasogastric tubes and epidural anaesthe-sia were not used. Patients participated in a protocol of earlydiet and early ambulation, and were discharged after meet-ing defined criteria. Fifty-eight patients (97%) were deemedsuitable for the ‘fast track’ approach at the time of surgeryand stayed for a mean (S.D.) of 4.3 (1.6) days after opera-tion. Three patients (5%) required a nasogastric tube forvomiting. No readmissions were directly attributable to ‘fasttrack’ failure, although four patients (7%) were readmittedwithin 30 days of operation for other reasons. Eight poorlycompliant patients stayed for 5.1 (1.1) days (P = 0.02versus compliant patients).

A comparison of outcomes after colonic resection andconventional care with fast-track multimodal rehabilita-tion was carried out by Basse et al (2004). However, the

Risk Management 123

TABLE 3.36 ESTIMATION OF BASAL METABOLIC RATE

Equation Subset of subjects FormulaHarris and Benedict Males BMR (kJ/day) = (57.5 × W) + (20.9 × H) − (28.3 × A) + 278

Females BMR (kJ/day) = (40.0 × W) + (7.7 × H) − (19.6 × A) + 2741Schofield Males, 30–60 years BMR (MJ/day) = (0.048 × W) + 3.653

Females, 30–60 years BMR (MJ/day) = (0.034 × W) + 3.538Males, over 60 years BMR (MJ/day) = (0.049 × W) + 2.459Females, over 60 years BMR (MJ/day) = (0.038 × W) + 2.755

From Bauer et al (2004).

BMR, basal metabolic rate.

two populations compared were treated in separate hos-pitals: 130 consecutive patients receiving conventionalcare (group 1) in one hospital were compared with 130consecutive patients receiving multimodal, fast-trackrehabilitation (group 2) in another hospital. Median agewas 74 years (group 1) and 72 years (group 2) and theASA score was significantly higher in group 2 (P < 0.05).Defecation occurred on day 4.5 in group 1 and day 2 ingroup 2 (P < 0.05). Median hospital stay was 8 days ingroup 1 and 2 days in group 2 (P < 0.05). The overallcomplication rate (35 patients) was lower in group 2 (P < 0.05), especially cardiopulmonary complications(five patients; P < 0.01). Readmission was necessary in12% of cases in group 1 and 20% in group 2 (P > 0.05)(Basse et al, 2004).

Nygren et al (2005) performed a comparative study ofoutcomes from four European units practising conven-

tional colorectal surgery with the reference ‘fast-track’unit in Denmark. The study populations consisted of451 consecutive patients from the conventional units(Sweden, n = 109; UK, n = 87; Netherlands, n = 76,Norway, n = 61) and 118 from the Danish centre. Basedon the P-POSSUM scores, the case mix was similarbetween centres. There were no differences in morbidityor 30-day mortality between the different centres. Themedian length of stay was 2 days in Denmark and 7–9days in the other centres (P < 0.05). The readmission ratewas 22% in Denmark and 2–16% in the other centres (P< 0.05). Thus, when compared with traditional care, fast-track perioperative care is associated both with a reducedlength of hospital stay but also with a higher readmissionrate (Table 3.38).

A small, randomised comparison between conventionalcare (n = 11) and a 10-point optimisation programme(n = 14) was reported by Anderson et al (2003) for patientsundergoing elective right or left hemicolectomy. In thiscomparison the optimisation programme was associatedwith maintained grip strength, earlier mobilisation (46 ver-sus 69 hours; P = 0.043) and significantly lower pain andfatigue scores. Patients in the optimisation group tolerateda regular hospital diet significantly earlier than controls(48 versus 76 hours; P < 0.001). In addition, the optimi-sation programme significantly reduced the median lengthof hospital stay (3 versus 7 days; P = 0.002) (Andersonet al, 2003).

Zutshi et al (2005) recently compared the utility of tho-racic epidural anaesthesia with PCA in patients who hadlaparotomy colonic resection and were then managed ona fast track protocol. There was no difference in length ofstay (5.8 versus 6.2 days, thoracic epidural versus PCA,P = 0.55), total length of stay (including readmissions),pain scores, quality of life, complications or hospital costsat any time point. They concluded that thoracic epiduraloffers no advantage over PCA for patients undergoingmajor intestinal resections who are on a fast-track post-operative care plan. Patients undergoing ileocolic resec-tion for Crohn’s disease appear to do well on ‘fast-trackprotocols’: epidural analgesia, enforced postoperative oralnutrition and mobilisation with a scheduled stay of 2 days(Andersen and Kehlet, 2005). Following 32 consecutiveileocolic resections for Crohn’s disease in 29 patients, themedian time to defecation was 2.5 days and postoperativehospital stay was 3 days. During a 30-day postoperativefollow-up there was two readmissions, one for mechanicalbowel obstruction (9 days) and one because of fever andvomiting (6 days). Wind and others (2006) compared 6studies using fast track surgery compared with conven-tional surgery, 3 of which were randomised studies. Fasttrack was safe, shortened hospital stay and readmissionrates were not increased. Despite these results King andothers (2006) found that these advantages did not influ-ence quality of life or health care economic outcomes.

For patients undergoing laparoscopic sigmoid colec-tomy, Raue et al (2004) found that a fast-track protocol(epidural analgesia, early oral feeding and enforcedmobilisation) shortened the time to patient discharge.Comparisons were made after laparoscopic sigmoidresection between 29 standard-care patients (19 men and


TABLE 3.37 NURSING CARE PROGRAMMEAND GOALS AFTER ELECTIVE COLONICRESECTION USING ENHANCED RECOVERY

Before surgeryRepeat information about perioperative coursepreviously given in the outpatient clinic. Discusswith family the 2-day postoperative program. Fluidnutrition including four protein drinks for 3 days.Laxatives and bowel cleansing

After surgeryDay of surgery 0–24 hoursMobilised: 2 hours, initiated 6 hours postoperativelyDrinking: 1000 mL including 2 protein drinksOral paracetamol 2 g q12 oral magnesium 1 g q12and cisapride 20 mg q 12 (repeated duringsubsequent days)Additional bupivacaine, ibuprofen and opioid (in thatorder) only for breakthrough painNormal food allowed

Postoperative day 1 (24–48 hours)Urinary catheter removed in the morningMobilisation 8 hoursNormal food and oral fluid > 2000 mL, including fourprotein drinksPlan discharge

Postoperative day 2 (48+ hours)Epidural catheter removed in the morningOral ibuprofen 600 mg q 8 hoursFull mobilisation and normal oral intakeStop cisapride, continue magnesium for 1 weekunless diarrhoea presentDischarge after lunch (48 hours postoperatively)

Postoperative day 8Check-up in outpatient clinicSuture removal and further treatment depending onhistology

Postoperative day 30Check-up in outpatient clinic

10 women) and 23 fast-track patients (15 men and 8women). On the first postoperative day, pulmonaryfunction was improved (P = 0.01) in fast-track patients.Oral feeding was achieved earlier (P < 0.01) and defeca-tion occurred earlier (P < 0.01) in the fast-track group.Fast-track laparoscopic sigmoidectomy patients weredischarged on day 4 (range 3–6 days) and standard-carepatients on day 7 (range 4–14 days) (P < 0.001).

All the elements of enhanced recovery after surgery(Figure 3.11) have been the subject of a consensus from TheEuropean Society of Clinical Nutrition and Metabolism(ESPEN) special interest group on management of patientsundergoing colonic surgery (Fearon et al, 2005).

In all, the Consensus Group (Fearon et al, 2005) makes20 recommendations as to perioperative care in promot-ing enhanced patient recovery:

● Consensus 1: a patient should receive oral and writtenpreadmission information describing what will happenduring their hospital stay, what they have to expect, andwhat their role is in their recovery.

● Consensus 2: patients undergoing colonic resection shouldnot receive routine oral bowel preparation. However,bowel preparation may be essential in selected patientswho require intraoperative colonoscopy.

● Consensus 3: patients should only be fasted for liquids for2 hours and for solids for 6 hours preoperatively. Patientsshould receive oral preoperative fluids and carbohydrateloading.

● Consensus 4: patients should not receive preanaestheticanxioloytic or analgesic medication.

● Consensus 5: patients should receive antithromboticprophylaxis according to the local peer-reviewed protocol.

● Consensus 6: patients should receive single-dose antibioticprophylaxis against both aerobic and anaerobic pathogens.

● Consensus 7: patients should undergo anaesthesiaavoiding long-acting opioids. Patients should receive amid-thoracic epidural commenced preoperatively andcontaining local anaesthetic in combination with alow-dose opioid.

● Consensus 8: patients should undergo laparotomy usingan abdominal incision of minimum length.

Risk Management 125

TABLE 3.38 COMPARATIVE OUTCOMES OF FAST TRACK IN DENMARK COMPARED WITHCONVENTIONAL PROGRAMMES IN EUROPE FOR COLORECTAL SURGERY

Total DK NL NO UK SEn 451 118 76 61 87 109Mortality: n (%) 10 (2) 6 (5) 2 (3) 1 (2) 1 (1) 0 (0)Readmissions: n (%) 49 (11) 26 (22) 6 (8)* 10 (16) 2 (2)* 5 (5)*Reoperations: n (%) 33 (7) 8 (7) 7 (9) 8 (13) 3 (3) 7 (6)Length of stay in hospital: median (IQR) — 2 (1) 8 (6)* 7 (3)* 9 (6)* 7 (5)*

After Nygren et al (2005)

DK, Denmark; LOS, NL, Netherlands; NO, Norway; SE, Sweden; UK, United Kingdom.

*P < 0.05 versus DK.

IQR, interquartile range.

Audit of compliance/outcomes

Perioperativeoral nutrition

Preadmissioncounselling

Early removalof catheters

Stimulationof gut motility

Prevention of nauseaand vomiting

Non-opiate oralanalgesics/NSAIDs

Routine mobilisationcare pathway

Warm air bodyheating in theatre Short incisions,

no drains

Avoidance of sodium/fluid overload

Short-actinganaesthetic agent

Mid-thoracic epiduralanaesthesia/analgesia

No nasogastric tubes

No premedication

No bowel preparation

Fluid andcarbohydrate-loading/

on fasting

ERAS

Figure 3.11 Enhanced recoveryafter surgery (ERAS). AfterFearon et al (2005).

● Consensus 9: nasogastric decompression tubes should notbe used as a routine in the postoperative period.

● Consensus 10: intraoperative maintenance of normo-thermia with infusion of warmed fluids and an upper-body forced-air heating cover should be used routinely.

● Consensus 11: drains are not recommended followingroutine colonic resection.

● Consensus 12: it is recommended that urinary bladderdrainage is used for the duration of thoracic epiduralanalgesia. Earlier removal of urinary drainage may beconsidered before the epidural is stopped.

● Consensus 13: antiemetics should be used selectively andin a structured manner to diminish postoperative nauseaand vomiting and promote an early return of oral intake.

● Consensus 14: patients should undergo a structured pat-tern of care to avoid postoperative ileus and promoteearly oral intake.

● Consensus 15: patients should receive continuous epiduralmid-thoracic low-dose local-anaesthetic/opioid combi-nations for 2 days after colonic resection. Paracetamolshould be given as a base-line analgesic (4 g daily)throughout the postoperative course. For break-throughpain, NSAIDs and bolus epidural bupivacaine should begiven whilst the epidural is running. NSAIDs should bestarted just before removal of the epidural and continueduntil and/or after discharge.

● Consensus 16: patients should be encouraged to commenceoral food intake 4 hours after surgery. Oral nutritionalsupplements should be taken (approximately 400 mLenergy-dense oral nutritional supplements) from the dayof surgery until a normal level of food intake is achieved.Continuation of oral nutritional supplements at home isrecommended for nutritionally depleted patients.

● Consensus 17: patients should be nursed in an environ-ment that encourages independence and mobilisation.A care plan that facilitates patients being out of bed for2 hours on the day of surgery and 6 hours thereafter isrecommended.

● Consensus 18: planning the discharge process shouldbegin when the patient attends for preadmissioncounselling. Defined discharge criteria should befollowed:● good pain control with oral analgesia● taking solid food, no intravenous fluids● independently mobile or same level as prior to admission● all of the above and willing to go home.

● Consensus 19: surgical units undertaking an enhancedrecovery programme must be restructured to provideadequate follow-up and continuity of care. An enhancedrecovery programme should only be initiated once thereis a clear pathway established for the prompt and safereadmission of the 1–3% of patients who will experiencean anastomotic leak (or other major complications) athome.

● Consensus 20: audit is an inherent and essential compo-nent of every enhanced recovery programme.

Many of these recommendations are not contentiousbut others do reflect a departure from what has until now represented conventional care. The proponents ofenhanced recovery state (Lassen et al, 2005) that surgicalpatients remain exposed to unnecessary starvation, sub-optimal stress reduction and fluid overload. While furtheroutcome studies are required, enhanced recovery with orwithout early hospital discharge is clearly desirable aftercolon and rectal surgery.


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