Surgical Challengesin the treatment of cIAI (complicated Intraabdominal Infection)

Reno Rudiman

Hasan Sadikin General Hospital, Bandung, Indonesia

DefinitionInfections that spread beyond the hollow viscus of origin into the peritoneal space and are associated with:

Abscess formation or

Peritonitis

PeritonitisPrimary = spontaneous bacterial peritonitis

arises without a breach in the peritoneal cavity or GI tract

Secondary

spillage of gut organisms through a physical hole in the GI tract or through a necrotic gut wall

community acquired or healthcare associated

Tertiary

peritonitis in a critically ill patient which persists or recurs at least 48 h after apparently adequate management of primary or secondary peritonitis

Microbiology:Abscesses or secondary peritonitis

Health care associated intra-abdominal infection

Community acquired infections

Infections derived from stomach, duodenum, biliary system and proximal small bowel:

Gram positive and Gram negative aerobic and facultative bacteria

Distal small bowel:

Gram negative facultative and aerobic bacteria

Anaerobes

Large bowel:

Facultative and obligate anaerobic bacteria

Streptococi and enterococci commonly present

Clinical features of cIAIDifficult to diagnose in the critically ill patient because history is usually unobtainable and physical signs usually masked by decreased conscious level

Clinical features of cIAIConsider diagnosis in the appropriate clinical setting in patients with otherwise unexplained signs of sepsis or organ dysfunction:

recent abdominal surgery

source of arterial emboli

peripheral vascular disease

thrombotic disorder

recent arteriography

history of reduced splanchnic blood flow(eg use of vasopressors or prolonged shock)

Clinical features of cIAI

Suspicion of intra-abdominal infection

Unexpected shortness of breath

supraventricular tachycardia occurring 3-4 days after an abdominal operation

new onset renal dysfunction

elevated bilirubin or transaminases

InvestigationsMicrobiological

Blood cultures

often negative

polymicrobial or anaerobic bacteraemia should raise possibility of anaerobic infection

Community acquired infections: Gram stain of no value

Healthcare associated infections: Gram stain may be valuable in S.aureus or Enterococcus spp. infections

AXR

Ultrasound

CT abdomen

Invasive Investigations in ICU

Probing of surgical wounds with sterile culture swab or gloved finger can often identify collections of infected material immediately adjacent to incision

Diagnostic peritoneal lavage

may reveal bacteria, white cells, bile or intestinal contents

bloody lavage return suggests acute intestinal ischaemia

Bedside laparoscopy

difficult

experience in critically ill patients largely anecdotal

Management of cIAI

Physiological resuscitation

Systemic antibiotics

Source control

Physiologic resuscitation: Early Goal Directed Therapy

What is Source Control?All those physical measures that are undertaken

To eliminate a focus of infection

To control ongoing contamination

To restore premorbid anatomy & function

What is Source Control?Not always surgical procedures, also include

Radiologically directed drainage of abscess

Removal of colonized urinary or vascular catheter

Removal of devitalized tissue by frequent dressing changes

Term Definition

Source controlAll physical measures undertaken to eliminate a

source of infection, control ongoing contamination, and restore premorbid anatomy and function

SinusAbnormal communication to an epithelial cell-lined

surface

FistulaAbnormal communication between two epithelial

cell-lined surfaces

AbcessFluid-filled collection of tissue fluid, tissue debris,

neutrophis, and bacteria contained within a fibrous capsule

Drainage Creation of a controlled sinus or fistula

DebridementRemoval of devitalized tissue, foreign bodies, or other areas advantageous to bacterial growth

Principles of Source Control

Drainage of abscess

Debridement of nonviable of infected tissue

Definitive management of the anatomic abnormality responsible for ongoing microbial contamination & restoring normal function and anatomy

Drainage

• Converting a contained collection to a controlled fistula (to exterior) or sinus

• Drain must permit free flow of the abscess

• Minimum risk and physiologic derangement: percutaneous drainage

• Modern imaging: all collections can be visualized preoperatively

• In unstable and ill patient – surgery for controlled sinus/fistula & removal of dead tissue only

DrainageCT guided abcess drainage

Debridement

• The process of removing nonviable tissue

• Directed against solid components that promote bacterial growth

• Demarcation between viable and nonviable tissue maybe not absolute at early stage

• Gentle debridement - use wet to dry saline dressing

Debridement• Remove all necrotic tissue but minimize the

resulting defects for easier reconstruction

• Bleeding from viable tissue is better than fail to debride necrotic material

DebridementNecrotic bowel

• Excision for necrotic bowel is more complex

• The benefits of resection must be weighed against the consequences of loss of bowel length

• The dilemma is usually best resolved by a planned second-look laparotomy

DebridementRetroperitoneum

• Peripancreatic retroperitoneal necrosis is well tolerated

• Blind exploration of retroperitoneum - risk of uncontrollable hemorrhage

• Delayed debridement is preferred for suspected infected necrosis

DebridementForeign body

• Risks are minimal when urinary or vascular catheter is infected

• Risks are high when aortic graft or heart valve is infected

Definitive management

• The ultimate aim of therapy: • to restore function with the least risk• To correct the abnormality that created the infection

Extent of Surgical Therapy

• The more extensive the initial intervention, the greater is the challenge of subsequent reconstruction

• The optimal intervention is that which accomplishes the source control objectives in the simplest manner

Failed Source Control

• Failure of source control is more important than antibiotic failure

• Cause of failure:• Poor choice of operation• Correct operation performed poorly• Poor timing

• Consequences of failure:• Nosocomial infections• Nutritional and metabolic disorders• Multiple organ dysfunction syndrome

Diffuse Peritonitis

• Aggressive initial surgical source control : intraoperative lavage

• If source control not possible• Continuous lavage• Laparostomy• Planned reexploration• Or combination of above

Complications of Source Control

• Complications from• Technical error• Local factors that impair healing

Source Control

Should be individualized based on:

Diagnostic uncertainty

Physiologic stability

Premorbid health status

Previous surgical interventions

Surgeon’s experience & skill

Available surgical facilities

AntibioticsHigh risk patients should be given antibacterials with a wider spectrum of activity

Risk factors:

higher APACHE II

poor nutritional status

significant cardiovascular disease

inability to obtain adequate source control

immunosuppression

Antibiotics

Should be active against enteric Gram negative aerobic and facultative bacilli and ß-lactam susceptible Gram positive cocci

For distal small bowel and colon-derived infections antibacterials should cover anaerobes

Same recommendation also applies to more proximal GI perforations when obstruction is present

AntibioticsSuitable regimes include:

imipenem/cilastin, meropenem, doripenem

3rd or 4th generation cephalosporin plus metronidazole

ciprofloxacin plus metronidazole

aztreonam plus metronidazole

piperacillin/tazobactam

Risk Factors for Treatment Failure

Patient factors

• Age, comorbidity, malnutrition

• Prolonged hospital stay, Antibiotic resistance

• Severity of illnessSurgical factors

• Inadequate source control

Ineffective antibiotic therapy

ModifiableRisk

Factors

Surg Inf 2002(3):175-233

Conclusion

Management of cIAI includes: physiologic resuscitations, systemic antibiotics and source control

The key to success when treating surgical infections is timely intervention to stop the delivery of bacteria and adjuvants of inflammation/infection into the peritoneal cavity

All others are useless if source control failed