What is the appropriate treatment for a patient with abdominal infection sepsis?

Management of Abdominal Infection Sepsis

For patients with abdominal infection sepsis, immediately initiate aggressive fluid resuscitation with crystalloids, administer broad-spectrum antibiotics within the first hour, and perform emergency surgical source control as soon as possible—even while resuscitation continues—as delays in any of these interventions significantly increase mortality. 1, 2

Immediate Recognition and Initial Resuscitation

Early recognition is the critical first step. Use the SOFA score to identify organ dysfunction (≥2 point increase defines sepsis), assessing respiratory function (PaO2/FiO2), Glasgow Coma Scale, mean arterial pressure/vasopressor requirements, bilirubin, platelets, and creatinine. 1 In resource-limited settings, use simple physiological parameters: systolic blood pressure, pulse rate, respiratory rate, temperature, oxygen saturation, and level of consciousness combined with abdominal examination findings (pain, rigidity). 1

Measure serum lactate immediately as part of the initial evaluation, though elevated lactate alone no longer defines sepsis—it is used to define septic shock when combined with vasopressor requirements. 1, 2

Fluid Resuscitation Protocol

• Begin crystalloid infusion immediately upon recognizing sepsis or hypotension—crystalloids are first-line therapy due to their tolerability and cost-effectiveness. 1, 2
• Administer 30 mL/kg of intravenous crystalloid within the first 3 hours for sepsis-induced hypoperfusion. 3
• Target mean arterial pressure (MAP) ≥65 mmHg as the initial hemodynamic goal. 2, 3, 4
• Titrate resuscitation to clinical response, not rigid protocols—monitor skin color, capillary refill time, mental status, and urine output (target >0.5 mL/kg/hour). 1, 2
• Use ultrasound to measure inferior vena cava (IVC) diameter to guide fluid administration; IVC distensibility index >15% during expiration predicts fluid responsiveness, while diameter >21 mm suggests adequate filling. 1, 2, 4
• Stop fluid administration when no improvement in tissue perfusion occurs or when signs of fluid overload develop (basal lung crepitations, elevated IVC diameter), as excessive fluids worsen intra-abdominal hypertension and abdominal compartment syndrome. 1, 3

Vasopressor Support

• Add norepinephrine as first-line vasopressor if hypotension persists after initial fluid resuscitation. 2, 3, 4
• Do not delay vasopressor initiation if adequate IVC diameter is achieved but hypotension continues. 4
• In resource-limited settings where norepinephrine is unavailable, epinephrine is an acceptable alternative. 1

Antimicrobial Therapy

Administer broad-spectrum intravenous antibiotics within 1 hour of recognizing sepsis—each hour of delay significantly increases mortality, particularly in septic shock. 1, 2, 3

Antibiotic Selection and Timing

• For septic shock, give antibiotics as soon as possible, ideally within the first hour. 1, 2
• For patients without septic shock, initiate antibiotics in the emergency department within the first 8 hours. 1, 2
• Obtain blood cultures (at least two sets) and intraoperative cultures before antibiotics, but do not delay therapy for this purpose. 2, 3
• Ensure satisfactory drug levels during source control procedures, which may require additional antibiotic administration just before surgery. 1

Empiric Antibiotic Regimens

Cover gram-negative bacilli (including Pseudomonas aeruginosa), anaerobes, and gram-positive organisms. 2, 3 Based on FDA-approved regimens for complicated intra-abdominal infections:

• Meropenem 1 gram IV every 8 hours for complicated intra-abdominal infections (covers broad spectrum including Pseudomonas). 5
• Piperacillin-tazobactam 3.375 grams IV every 4-6 hours or 4.5 grams every 6-8 hours for intra-abdominal infections. 6

Adjust doses for renal impairment: For meropenem, reduce to every 12 hours if creatinine clearance 26-50 mL/min, and to half-dose every 12 hours if 10-25 mL/min. 5

Duration and De-escalation

• Administer a short course of 3-5 days after adequate source control. 2
• Reevaluate in 24-48 hours based on cultures and clinical response. 2
• De-escalate to targeted therapy once pathogen and sensitivities are identified. 2

Surgical Source Control

Source control is absolutely essential—abdominal sepsis cannot be successfully treated with antibiotics alone, unlike extra-abdominal sepsis. 1 Delay in adequate source control is directly associated with increased mortality. 1

Timing of Intervention

• Patients with diffuse peritonitis require emergency surgical intervention immediately, even if physiological stabilization measures must continue during the procedure. 1, 2
• For hemodynamically stable patients without acute organ failure, intervention may be delayed up to 24 hours if adequate antibiotics are administered and close clinical monitoring is ensured. 1, 2
• In the most severe cases, proceed with source control even while ongoing resuscitation continues, as the patient may die before being "optimized" for surgery. 1

Source Control Objectives

The surgical procedure must accomplish three goals: 1, 2

1. Drain infected foci and fluid collections
2. Control ongoing peritoneal contamination through diversion or resection
3. Restore anatomical and physiological function to the extent feasible

Approach Selection

• Percutaneous drainage is preferable to surgical drainage for well-localized abscesses and fluid collections in hemodynamically stable patients. 1
• Emergency laparotomy is mandatory for diffuse peritonitis, intestinal perforation, or necrotizing infection. 1, 3
• Damage control surgery with abbreviated laparotomy should be utilized in patients with severe physiological derangement, leaving the abdomen open with temporary abdominal closure and planning staged reoperations. 7
• Mandatory or scheduled relaparotomy is not recommended in the absence of intestinal discontinuity, abdominal fascial loss, or intra-abdominal hypertension. 1

Diagnostic Imaging

• CT scan is the imaging modality of choice in adult patients not undergoing immediate laparotomy to determine the presence and source of infection. 1
• Further imaging is unnecessary in patients with obvious signs of diffuse peritonitis who require immediate surgical intervention. 1
• In resource-limited settings, use ultrasound and plain abdominal X-ray as cost-effective alternatives. 1

Monitoring and Ongoing Assessment

• Continuously evaluate SOFA score components to assess organ dysfunction progression. 1, 2
• Monitor for intra-abdominal hypertension and abdominal compartment syndrome, especially in patients receiving aggressive fluid resuscitation. 1, 2, 3
• Follow serial lactate measurements to assess adequacy of resuscitation and tissue perfusion. 2, 3, 4
• Perform regular clinical examinations multiple times daily to assess for improvement or deterioration. 3

Critical Pitfalls to Avoid

• Do not delay antibiotics—each hour of delay in septic shock significantly increases mortality. 1, 2
• Do not postpone surgical source control—inadequate or delayed source control is the main determinant of poor outcome. 1, 7
• Do not use rigid early goal-directed therapy protocols—recent trials (ProCESS, ARISE, ProMISe) show no mortality benefit over clinical judgment-guided care; titrate to individual clinical response. 1, 3, 4
• Do not continue aggressive fluid resuscitation once adequate perfusion is achieved—this increases risk of intra-abdominal hypertension and abdominal compartment syndrome. 1, 3, 4
• Do not use hydroxyethyl starches for fluid resuscitation—they are associated with worse outcomes. 3, 4
• Do not fail to de-escalate antibiotics—failure to narrow the spectrum contributes to antimicrobial resistance. 2
• Do not use central venous pressure alone to guide fluid therapy—it poorly predicts fluid responsiveness. 4