The Anaesthetic Assessment of an Elderly Surgical Patient

Dr. Irwin FooConsultant Anaesthetist and Honorary

Clinical Senior Lecturer

Department of Anaesthesia

Western General Hospital

Edinburgh

Scope of the lecture

• Anaesthetic definition of elderly and workload

• How elderly patients differ from younger counterparts

• The current state of affairs and why there is room for improvement

• Importance of good anaesthetic assessment• Concept of functional reserve/capacity• Perioperative management

Anaesthetic Definition of ‘Elderly’

• AAGBI document (2001)– > 80 yrs = elderly – Physiological changes/functional decline

most marked after 80 years

• Chronological vs biological age– Chronological age - poor discriminator of

individual surgical risk– ‘old’ 60 yr old vs ‘young’ 80 yr old– Heterogenecity - most consistent feature

in the elderly population

Variability of organ function with age

0

20

40

60

80

100

20 30 40 50 60 70 80 90

% ORGAN FUNCTION

AGE (YEARS)

‘YOUNG’

‘AVERAGE’

‘OLD’

Size of the problem

• Increasing numbers– > 80’s -fastest growing section of the

population

– 2005- >20% of population 65 yrs and over

• increasing workload– 50% of elderly will require anaesthesia for

surgical intervention in their lifetime

– surgical/anaesthetic advances

Anaesthetic/Surgical Workload in the Elderly Population

10

12

14

16

18

20

22

24

26

85 86 87 88 89 90 91 92 93 94

(%)

(YEAR)

Anaesthetised population

Resident population

Klopfenstein CE et al. Anesth Analg 1998; 86:1165-70

How do elderly surgical patients differ from younger counterparts ?

• Anaesthetising the elderly……….

• “Applied clinical pharmacology with enough patho-physiology included to confuse the picture”

Comorbidity in the elderly

• Increasing medical conditions with age

CVS RS CNS

No preoperative

problems(20%)

n = 288Vaz FG et al. Age and Ageing 1989; 18: 309-315

% ofpatients

Extent of surgical stress(patients > 90 yrs; n = 301)

Type of surgery

Mortality after2 days (%)

Mortality after30 days (%)

Major vascular 20.0 20.0

Thoracotomy 12.5 37.5

Biliary, liver 6.7 26.7

Bowel, rectal, anal 3.8 23.8

Hip 2.7 8.2TURP, eye 0.0 0.0

Warner et al, Ann Surg 1988; 207: 380 -386

Variable physiological ageing in the elderly

0

20

40

60

80

100

20 30 40 50 60 70 80 90

% ORGAN FUNCTION

AGE (YEARS)

‘YOUNG’

‘AVERAGE’

‘OLD’

The main risk factors determining outcome in the elderly

• Severity of co-existing disease

• Surgical procedure

• Physiological age

How are we doing?

The Good News…………

Outcome of Anaesthesia and Surgery in people > 100yrs and olderWarner et al JAGS 1998; 46:988

• Retrospective study• n = 31 (100-107yrs)• GA 39% RA 35%

Sedation 26%• 1 major complication

within 48hrs• Mortality rates

– 48hrs 0%

– 30 day 16%

– 1 year 36%

The Bad News……….

Highest incidence of mortality and morbidity- NCEPOD data

Remained constant despite advances in anaesthesia/surgical techniques

• NCEPOD 1998/1999 -

Likely Explanations

• British surgical patients have on average a worse ASA status than 10yrs ago

• ASA Physical Status categories:• Class 1: a normally healthy patient• Class 2: patient with mild systemic disease• Class 3: patient with moderate to severe

disease that is not incapacitating• Class 4: patient with incapacitating disease that is a

constant threat to life• Class 5: moribund patient- not expected to survive 24

hrs with or without an operation

Likely Explanations

• 9 out of 10 patients aged > 60yrs receiving GA have ASA status of 2 and over

• 21% > 65yrs developed one or more in-hospital postoperative complications

Relevance of postoperative complications

• Hospital postoperative complications shortens long-term survival (Manku et al, 2003)– 7 x risk in the first 3 months after surgery

• (3 x without complications)

– In-hospital risk factors:- pulmonary and renal complications

– Other factors:- history of cancer, ASA>II, age, history of neurological disease

Hospital postoperative complications shorten long-term survival

Relative risk of mortality:0-3 months 3-12 months > 12 months

No complications 2.9(1.8-4.6)

2.3(1.7-3.2)

1.3(1.04-1.7)

With complications 7.3(3.8-14)

2.4(1.2-4.6)

1.9(1.2-3.1)

No complicationsAge > 80 yrs

1.7(0.8-3.8)

1.6(0.98-2.5)

1.1(0.84-1.6)

With complications 6.2(2.6-14.9)

2.4(1.06-5.3)

2.1(1.2-3.6)

Room for improvement?

NCEPOD report- extremes of ages 1999

Recommendations

• lack of senior multidisciplinary care• poor fluid management• matching of experience of

surgeon/anaesthetist to physical status of elderly patient

• Appropriate postoperative care

• Effective pain management

Scottish Audit of Surgical Mortality - Case Assessments Booklet - 2004

• Four hourly bags of iv fluids can drown an elderly patient

• Elderly patients have limited physiological reserve

• Cardiovascular collapse during orthopaedic surgery

• Unnecessary laparotomy on elderly patient

How we can improve the management of the elderly surgical patient ?

• Adequate anaesthetic assessment• identification of failing integrated responses/functional

reserve of individual organs• plan appropriate anaesthetic technique

• Optimisation preoperatively – multidisciplinary approach

• Estimate likely outcome of proposed surgery (alter if necessary)

• ? day or inpatient surgery• Postoperative placement

Preoperative Assessment

• Assessment of damaging effects of concurrent medical conditions

• Influence of normal ageing processes

• Functional reserve/capacity assessment: both intergrated and individual organs

• Specific elderly issues e.g. postoperative cognitive dysfunction (POCD)

The effects of ageing• Progressive loss of functional reserve in all

integrated and single organ systems• Invisible loss until 70-80% loss of reserve

has occurred• Anaesthesia/surgical insult often utilises

50% or more of functional reserve

0

20

40

60

80

100

20 30 40 50 60 70 80 90

% Maximal Organ Function

Basal

MaximalFunctional

Reserve

The effects of ageing

• Clinical signs of failure in any organ system indicates complete loss of functional reserve

• Confusion/delirium developing postoperatively suggests poor cognitive reserve

• Preoperative assessment aim is to identify systems at risk of failure and to try and minimise risk (if possible)

Traditional diagnostic approach

CNS CVS RS GI UGS Immunesystem

History of presenting illness

Medical/Surgical history

Physical examination

Investigations

Diagnosis and Mx plan

Organ-system based approach for preoperative assessment

CNS CVS RS GI UGS Immunesystem

Medical and surgical history

Activity level and quality

Physical examination

Investigations

Assessment of organ system reserve

Brief reminder of age-related changes

Age-related cardiovascular changes

• Reduced autonomic responsiveness• SNS activity ;Parasympathetic • Baroreceptor reflex activity -adrenoceptor responsiveness

• Decreased maximum heart rate• Frank-Starling mechanism- major

mechanism for maintaining stroke volume

Priebe H-J. BJA 2000; 85:763 - 78

Age-related cardiovascular changes

• Increased vascular stiffness– systolic BP– widening of pulse pressure

• Left ventricular wall thickening compliance: impairment of diastolic

function• Greater dependence on atrial function for

ventricular filling– contribute up to 30% of SV

Priebe H-J. BJA 2000; 85:763 - 78

Age-related respiratory changes

Vital capacity / Residual volume• strength and mobility of muscles

• lung elastic recoil • chest wall compliance • spinal collapse (anterior wedging)

closing volume/capacity V/Q abnormalities → gas exchange

Effect of age on closing capacity and FRC

0

1

2

3

30 40 50 60 70

Lung volume (L)

Age (years)

FRC, upright

FRC, supine

Closing capacity

Postoperative PaO2 in the Elderly

0

20

40

60

80

100

120

140

160

20 30 40 50 60 70 80

Oxygen by facemask

No Oxygen supplement

Postoperative PaO2 (mmHg)

Age (years)Patients with no preexisting pulmonary disease

Age-related respiratory changes

hypoxic and hypercapnic reflex control• Poor upper airway tone

– snoring almost universal

• Poor cough (7 fold reduction in sensitivity of cough reflex)

risk of aspiration (silent!!)• Chest wall rigidity more dependent on

the diaphragm

Age-related neurological changes brain cell mass (10-30% by age 80)

– loss of central cholinergic and dopaminergic cells

– 70-80% loss of dopaminergic function required before symptoms seen in Parkinson’s disease

– ‘Crystallised’ intelligence better preserved than ‘liquid’ intelligence

• Poor reflex control– baroreceptor , thermoregulation

Age-related neurological changes

• Blindness – cataracts, glaucoma– problem with visual analogue scales

• Deafness – problems with comprehension– may be denied by patient

• Cognitive impairment– dementia present in 22% of over 80’s– (life expectancy-50% in 5yrs)

Age-related hepatic changes

liver mass and blood flow– 1% loss/yr after 30 yrs– minor changes in cytochrome P450 activity– variable effect on Phase I reactions; Phase II not

affected

• Drugs which are flow-limited affected greater than capacity limited– lignocaine/bupivacaine, opioids

• Reduced albumin: altered drug binding

Age-related renal changes

• Marked decline in RBF and GFR (1% loss of function/yr after 30yrs)

• Plasma creatinine: not good guide of renal function bec. of reduced muscle mass

• Response to Na concn impaired; less able to excrete Na load

• Reduced ability to dilute/concentrate urine thirst perception– fear of incontinence– locomotor problems-inability to get to fluids

Age-related musculoskeletal changes

• Osteoarthritis/Osteoporosis– immobile venous stagnation– limits ability to exercise

• Poor stability/balance risk of accidents esp. in unfamiliar

surroundings

• Ligamental laxity– cervical vertebrae slip

Functional Reserve/Capacity Assessment

Integrated functional reserve

• Metabolic equivalence– attempt to quantify metabolic (O2 delivery)

capacity of the patient– estimates the likely outcome of surgery– predicts the likelihood of postoperative

complications• patients unable to reach 4 METS

Examples of metabolic equivalents

Score Activity1 Eat and dress, walk indoors

around the house2 Walk a block on the level, do

light work around the house4 Climb a flight of stairs or walk

uphill, heavy domestic work, runa short distance

6 Moderate recreational activitiese.g. dancing, golf, doubles tennis

10 Strenuous sports e.g. swimming

Integrated functional reserve

• METS-dependent on patient history

• McGlade et al. Anaesth Intensive Care 2001; 29:520-6– compared reliability of patients as historians

– used a questionnaire and a simple exercise test

– 14% of patients who claimed they could climb a flight of stairs declined to do so

• watching them climb a flight of stairs more reliable

Cardiopulmonary Exercise Testing in elderly patients undergoing major

surgery Older et al. Chest 1999;116:355-62

CPX testing: gold standard for identifying high-risk patients

• bicycle ergometer/ metabolic cart– computerised analysis of

gas exchange data/ 12 lead ECG data

– anaerobic threshold (AT)

– AT < 11ml/min/kg equivalent to less than 4 METs

CPX testing:as screening test for perioperative management

CPX testing: gold standard for identifying high-risk patients?

• excellent predictor of mortality from cardiopulmonary causes postop– allows appropriate placement

• good safety record

• Drawbacks– requires up to 1hr per patient – not all elderly patients can perform test

Functional reserve of individual organs

• Cardiac assessment-– ECG most useful

– abnormality in up to 60%

– asymptomatic systolic murmur require further investigation: NCEPOD 2001

• aortic valve sclerosis: 48%;

• calcific aortic valve stenosis: 4%

– Normal systolic cardiac failure• disorder of the elderly

• ? role of brain natriuretic peptide in Dx

Guidelines for Preoperative Resting Echocardiography

• Previous CCF or MI with a reduction in functional capacity (< 4 METS)

• Dyspnoea not explicable by pulmonary disease (on PFTs) or obesity, with an abnormal ECG

• Cardiac murmur with one or more factors below• Reduced functional capacity (< 4 METS)

• Chest pain

• Orthopnoea

• PND

• Peripheral oedema

• Cardiomegaly (on CXR)

• Abnormal ECG (arrhythmia, conduction defect, LVH)

Functional reserve of individual organs• Respiratory assessment-

– Pulse oximetry on air (lying and standing)– Hx of snoring should be actively sought

• Renal assessment-

– use Cockcroft Gault Formula

• converts serum creatinine to creatinine clearance

– CC (ml/min) =(140 - age) x wt (kg) x (1.04 for )llllllllllll

creatinine (μmol/l)

• 88yr old female for colectomy, weighing 40kg with a serum creatinine of

100 μmol/l.

• Calculated creatinine clearance = 21.6 mls/min

Functional reserve of individual organs

• Neurological assessment - – delirium (acute confusional state) is an

independent predictor of adverse outcomes in older hospital patients

• prolonged hospital stay• functional decline risk of developing hospital-acquired

complication

– Incidence of postoperative delirium: 10-20%

Delirium

• Hx of previous postoperative delirium indicates incipient brain failure– ?avoid general anaesthesia/sedation

• Preoperative tests recommended– AMT– MMSE

• Serial testing using the AMT useful– abrupt decline of 2 or more points =

sensitive/specific indicator of delirium

Abbreviated mental testAgeTime (to the nearest hour)Address - to recall at the end of the test:

42 West Street (ask patient to repeat the address to ensure it has been heard correctly)

YearName of hospitalRecognition of two persons (e.g. doctor, nurse)Date of birthYear of start of the first world warName of monarchCount downwards from 20 to 1

Causes of delirium• medications• medications• medications• infection• hypoxia• pain• congestive heart failure• metabolic problems• some combination• something else

Neurological assessment • If AMT abnormal MMSE

– dementia likely if score less than 25– diagnosis of dementia should not be made lightly

(involve care of the elderly)– Issue of consent: Adult with Incapacity Act 2000

• Cerebrovascular disease of the vertebral arteries

• flexion/extension of the neck during intubation• test: looking up from sitting position without feeling

dizzy

Laboratory investigations• Blanket routine preoperative investigations

are inefficient, expensive and unnecessary– AAGBI working party publication (2001)

– Age per se is not an indication for preoperative testing

– Guided by history, clinical examination and proposed surgery

• NICE guidelines (2003)

Optimisation preoperatively

• Multidisciplinary team approach– care of the elderly

• mental state

• endocrine

• polypharmacy issues

– cardiology• murmurs (aortic stenosis)

• intractable cardiac failure

– physiotherapists, nutritionists

Outcome assessment and placement

• Inherent risk of operation– size of stress response– is it appropriate surgery?

• matching of experience of surgeon/anaesthetist to physical status of elderly patient

• Plan appropriate anaesthetic technique• Appropriate postoperative care

– ward/HDU/ICU

Day or inpatient surgery?• Minimises disorientation and stress for the patient

– Social support must be in place

• Outpatient surgery reduce postoperative cognitive dysfunction (ISPOCD2 group)– n = 372; > 60 yrs; no restriction on type of

anaesthetic/analgesia used– POCD = inpatient: 9.8%; outpatient: 3.5% at 7 days – Risk factors: age > 70yrs and in vs outpatient surgery

Preoperative management

• Premedication– avoid if possible– no benzodiazepines (esp. diazepam), centrally active

anticholinergics and intramuscular drugs– avoid pethidine

• Give all regular medications – including nicotine patches +/- alcohol

• Preoperative fluids (bowel prep) • Maintain dignity- dentures to remain in place

Postoperative cognitive deficit (POCD)

• Complex clinical picture that includes– disorientation

– delirium

– dementia

– personality changes

• Incidence of POCD - ISPOCD 1 (1998)– 1100 patients over 60yrs

– 25.8% deficit at 1 week

– 9.9% deficit at 3 months

– (still 10% at 2yrs)

Postoperative cognitive deficit (POCD)

• Causes of POCD– Not hypoxia or hypotension– Not general anaesthesia (ISPOCD 2- 2003) but lab

studies: ↑ ß-amyloid deposition with volatile anaesthetics

– Stress response to surgery• prolonged hypercortisolaemia• central catecholamine changes

– Decline in central cholinergic function– Genetic predisposition (APOE gene) –negative

studies

Futility

• Inappropriate procedure with no benefit in longevity– heroic surgical therapy– ‘senior’ decision to operate

• Palliative surgery must be provided for symptomatic relief

Case study 1

• 82 yrs• Scheduled for paraumbilical hernia

repair (laparotomy 15 yrs ago for small bowel obstruction)

• Preoperative cardiac murmur and 2 episodes of dizziness

• ECHO- critical aortic stenosis and moderately impaired LV

• Intermittent abdominal pain from hernia site

Case study 2

• 72yrs• Hartmann’s procedure for

perforated diverticular disease 1yr ago

• ‘Not quite the same - poor concentration, tends to get confused and more withdrawn

• Requesting reversal of Hartmanns as ‘cannot cope with bag’

To sum up………….

Young Elderly