Therapeutic Paracentesis in Spontaneous Bacterial Peritonitis
A repeat diagnostic paracentesis at 48 hours after initiating antibiotics is recommended to assess treatment response in patients with SBP, but routine therapeutic (large-volume) paracentesis is not indicated for SBP management itself.
Diagnostic Paracentesis for Treatment Monitoring
Response to empirical antibiotic therapy should be assessed by repeating diagnostic paracentesis 48 hours after initiation of treatment. 1 This follow-up tap serves a critical monitoring function rather than a therapeutic one.
Criteria for Treatment Response Assessment
Treatment failure is defined as a decrease in ascitic fluid PMN count <25% from baseline, which should prompt broadening of antibiotic coverage and investigation for secondary bacterial peritonitis. 1
If an organism is isolated and is susceptible to the antibiotic used, and the patient is improving clinically, repeat paracentesis may be unnecessary. 1
A second diagnostic tap at 48 hours helps identify antibiotic resistance or the presence of secondary peritonitis, which occurs in approximately 4.5% of cirrhotic patients with peritonitis. 1
When Diagnostic Paracentesis is NOT Required
Repeat paracentesis may be omitted if the patient demonstrates clear clinical improvement and culture results show a susceptible organism. 1 However, this decision requires careful clinical judgment based on:
- Documented organism susceptibility to the chosen antibiotic 1
- Clear clinical improvement (resolution of fever, abdominal pain, hemodynamic stability) 1
- No signs of treatment failure 1
Therapeutic (Large-Volume) Paracentesis in SBP
Large-volume therapeutic paracentesis is NOT part of the standard treatment protocol for SBP. The management of SBP centers on:
Immediate empirical IV antibiotics (third-generation cephalosporin for community-acquired SBP, or broader spectrum for nosocomial/healthcare-associated infections) 1
IV albumin administration (1.5 g/kg at diagnosis and 1.0 g/kg on day 3) to reduce risk of hepatorenal syndrome and mortality 1, 2
Antibiotic therapy duration of 5-7 days 1
Common Pitfalls to Avoid
Do not confuse diagnostic paracentesis (removing 10-20 mL for analysis) with therapeutic large-volume paracentesis (removing liters of fluid for symptomatic relief). 1 The former is essential for SBP diagnosis and monitoring; the latter addresses refractory ascites, not infection. 1
Do not delay the 48-hour follow-up paracentesis in patients who appear to be responding poorly, as this may indicate multidrug-resistant organisms requiring escalation of antibiotic therapy. 1, 3 Early identification of treatment failure is critical, as ineffective response to first-line treatment is an independent predictor of 90-day mortality (hazard ratio 20.6). 3
Avoid performing unnecessary repeat taps in clearly improving patients with documented susceptible organisms, as this exposes patients to procedural risk without added benefit. 1