Surgical Memo for Paracentesis
Pre-Procedure Requirements
Obtain informed consent from the patient before performing diagnostic or therapeutic paracentesis 1. This is a strong recommendation across all major guidelines.
Pre-Procedure Testing
Do NOT routinely measure prothrombin time, platelet count, or transfuse blood products before paracentesis 1. This represents a paradigm shift from older practice—coagulopathy and thrombocytopenia are not contraindications to paracentesis 2. The complication rate remains <1% even with abnormal coagulation profiles 1, 2.
Exception: If thrombocytopenia is severe (<40,000/mm³), most clinicians give pooled platelets, though this lacks strong evidence 2.
Procedure Technique
Site Selection
Use ultrasound guidance when available to reduce adverse events 1. The left lower quadrant is optimal—the abdominal wall is thinner and ascites depth is greater here 1.
Specific anatomical landmarks:
- Insert at least 8 cm lateral to midline and 5 cm above the symphysis pubis 1
- Avoid the inferior and superior epigastric arteries (run just lateral to umbilicus toward mid-inguinal point) 2
- Avoid enlarged liver or spleen 2
- The traditional site is approximately 15 cm lateral to the umbilicus in the left or right lower quadrant 2
Fluid Removal
For large volume paracentesis, drain all ascitic fluid to dryness in a single session over 1-4 hours 1. Do not perform serial small-volume taps when complete drainage is possible.
Post-drainage positioning: Have patient lie on the opposite side for 2 hours if fluid leakage occurs, and consider a purse-string suture around the drainage site 1.
Fluid Analysis
Diagnostic Paracentesis (10-20 mL sample)
Essential tests to send:
- Ascitic fluid cell count with differential (inoculate into EDTA tube) 2
- Ascitic fluid culture (inoculate at least 10 mL into aerobic and anaerobic blood culture bottles at bedside before antibiotics) 3, 2, 4
- Serum-ascites albumin gradient (SAAG) in preference to ascitic protein 2
- Ascitic fluid amylase if pancreatic disease suspected 2
Additional tests when PMN ≥250 cells/mm³:
- Total protein, LDH, glucose, and Gram stain to distinguish spontaneous bacterial peritonitis (SBP) from secondary peritonitis 3
Cytology: Only when malignancy is clinically suspected 2.
Post-Procedure Management
Albumin Replacement
For paracentesis >5 L: Administer 20-25% intravenous albumin at 8 g per liter of ascites removed 1, 5. This is a high-quality, strong recommendation to prevent post-paracentesis circulatory dysfunction.
For paracentesis <5 L: Consider albumin (same dose) in patients with:
- Acute-on-chronic liver failure (ACLF)
- High risk of post-paracentesis acute kidney injury
- Hypotension
- Renal insufficiency
- Electrolyte abnormalities 1, 5
Alternative plasma expanders (150-200 mL gelofusine or haemaccel) may be used for uncomplicated paracentesis <5 L 2, though albumin remains superior.
Antibiotic Therapy
Start empiric antibiotics immediately if ascitic fluid PMN count ≥250 cells/mm³ 3, 4:
- First-line: IV cefotaxime 2 g every 8-12 hours (or ceftriaxone) in settings without prevalent multidrug-resistant organisms 3, 4
- Nosocomial/ICU patients: Consider broader coverage with carbapenems due to increasing multidrug-resistant organisms 4
Also treat empirically if PMN <250 cells/mm³ but patient has:
- Temperature ≥100°F (37.8°C)
- Abdominal pain or tenderness
- Encephalopathy, renal failure, acidosis, or peripheral leukocytosis 3
For SBP with renal impairment: Add albumin 1.5 g/kg within 6 hours of diagnosis, followed by 1 g/kg on day 3 1, 2.
Follow-Up Paracentesis
Repeat paracentesis is NOT routinely needed in typical SBP cases (advanced cirrhosis, typical symptoms, single organism, dramatic response) 3.
DO repeat paracentesis if:
- Setting, symptoms, or ascitic fluid analysis are atypical
- Multiple organisms isolated
- Poor clinical response to antibiotics
- Suspicion of secondary peritonitis (PMN count rises despite treatment, unlike SBP where it falls) 3
Critical Pitfalls to Avoid
- Never place a chest tube for spontaneous bacterial empyema—treat with antibiotics only 4
- Avoid NSAIDs in cirrhotic patients with ascites—they reduce urinary sodium excretion and can convert diuretic-sensitive to refractory ascites 3
- Do not restrict fluids unless serum sodium <120-125 mmol/L 1, 3
- Bedside inoculation of blood culture bottles increases culture sensitivity to >90%—do not send fluid to lab first 4
Transplant Evaluation
All patients with cirrhosis and ascites should be considered for liver transplantation 3, 2, 5, as development of ascites increases annual mortality from <5% to 20% 5. This applies regardless of MELD score, as ascites is an independent predictor of mortality 5.