What is the recommended management of intra‑abdominal sepsis?

Management of Intra-Abdominal Sepsis

Intra-abdominal sepsis requires immediate simultaneous initiation of three interventions: aggressive fluid resuscitation, broad-spectrum antibiotics within 1 hour for septic shock (within 8 hours otherwise), and emergency surgical source control for diffuse peritonitis. 1, 2

Immediate Resuscitation (Start Immediately)

• Begin aggressive intravenous crystalloid resuscitation the moment hypotension or sepsis is identified, targeting mean arterial pressure ≥65 mmHg 1, 2
• Continue resuscitation measures during surgical intervention if needed—do not delay surgery waiting for "complete" stabilization 3, 1
• Add norepinephrine as first-line vasopressor if fluid resuscitation fails to restore adequate perfusion or hypotension persists 1
• Monitor response through skin color, capillary refill, mental status, urine output, and serum lactate levels 1
• Use ultrasonography to measure inferior vena cava diameter to guide fluid therapy 1

Antimicrobial Therapy (Within 1 Hour for Septic Shock)

For patients with septic shock, administer antibiotics as soon as possible—ideally within the first hour, as each hour of delay significantly increases mortality. 3, 1, 2

• For patients without septic shock, initiate antibiotics in the emergency department within 8 hours of presentation 3, 2
• Collect blood cultures (at least two sets) and plan for intraoperative cultures, but never delay antibiotics to obtain cultures 1, 2

Antibiotic Selection by Clinical Scenario:

Community-acquired infection (immunocompetent, non-critically ill):

• Piperacillin/tazobactam 4 g/0.5 g q6h or 16 g/2 g continuous infusion 3
• Alternative: Ertapenem 1 g q24h 3

Critically ill patients or septic shock:

• Meropenem 1 g q6h by extended infusion or continuous infusion 3, 2
• Alternative: Imipenem/cilastatin 500 mg q6h by extended infusion 3
• Alternative: Doripenem 500 mg q8h by extended infusion 3
• Alternative: Eravacycline 1 mg/kg q12h 3

Healthcare-associated infection:

• Use carbapenems as above, driven by local antibiogram data 2
• Add vancomycin to cover MRSA 2

Beta-lactam allergy:

• Eravacycline 1 mg/kg q12h or Tigecycline 100 mg loading dose then 50 mg q12h 3

Source Control (Emergency Surgery for Diffuse Peritonitis)

Patients with diffuse peritonitis require emergency surgical intervention as soon as possible, even if physiological stabilization measures must continue during the procedure. 3, 1, 2

Timing of Intervention:

• Diffuse peritonitis: Operate immediately 3, 1, 2
• Hemodynamically stable patients without acute organ failure: Intervention may be delayed up to 24 hours only if adequate antibiotics are administered and close clinical monitoring is provided 3
• Post-operative peritonitis: Early re-laparotomy (within 24 hours) significantly reduces mortality compared to delayed intervention 3

Source Control Methods:

• Surgical drainage is mandatory for diffuse peritonitis: drain infected foci, control ongoing peritoneal contamination through diversion or resection, and restore anatomical and physiological function 3, 1, 2
• Percutaneous drainage is preferable to surgery for well-localized abscesses when feasible and the patient is hemodynamically stable 3, 2
• Primary resection with anastomosis for clinically stable patients without major comorbidities 3
• Hartmann's procedure for critically ill patients or those with multiple major comorbidities 3
• Maintain satisfactory antimicrobial drug levels during source control procedures, which may require additional antibiotic administration just before the procedure 3

Duration of Antibiotic Therapy

• Administer antibiotics for 4 days in immunocompetent, non-critically ill patients if source control is adequate 3
• Extend to 7 days for immunocompromised or critically ill patients based on clinical conditions and inflammatory markers 3
• Continue antibiotics until clinical signs of infection resolve (normalized temperature, white blood cell count, return of gastrointestinal function) 2
• If clinical signs persist after 5-7 days, obtain CT or ultrasound imaging to identify persistent or recurrent infection requiring additional intervention 2
• De-escalate to targeted therapy once culture results and sensitivities are available to reduce resistance and toxicity 1, 2

Monitoring and Reassessment

• Use the SOFA score for organ dysfunction assessment (systolic blood pressure, heart rate, respiratory rate, temperature, oxygen saturation, level of consciousness) 1
• Measure serum lactate as part of initial assessment—levels >2 mmol/L with vasopressor requirement define septic shock 1
• Monitor for intra-abdominal hypertension and abdominal compartment syndrome, especially in patients requiring aggressive fluid resuscitation 1
• Obtain routine cultures from the infection site for higher-risk patients, particularly those with prior antibiotic exposure who are more likely to harbor resistant pathogens 3
• For community-acquired infections, obtain routine culture and susceptibility studies if there is significant resistance (10-20% of isolates) of common organisms like E. coli to empiric regimens 3

Critical Pitfalls to Avoid

• Never delay antibiotics to obtain cultures in septic shock—each hour of delay increases mortality 1, 2
• Never postpone surgical source control in diffuse peritonitis—inadequate or delayed source control is associated with significantly increased mortality rates 3, 1
• Never use narrow-spectrum agents for severe infections—these are only appropriate for mild-to-moderate community-acquired infections 2
• Never continue broad-spectrum antibiotics beyond clinical resolution—failure to narrow the spectrum contributes to antimicrobial resistance 1, 2
• Do not perform mandatory or scheduled relaparotomy in severe peritonitis unless there is intestinal discontinuity, abdominal fascial loss preventing closure, or intra-abdominal hypertension 3