What are the indications and guidelines for performing paracentesis in patients with ascites?

Indications and Guidelines for Paracentesis in Patients with Ascites

A diagnostic paracentesis is strongly recommended in all patients with new-onset ascites and in cirrhotic patients with ascites on hospital admission to rule out spontaneous bacterial peritonitis (SBP). 1

Diagnostic Paracentesis Indications

• A diagnostic paracentesis should be performed in all patients with new-onset ascites to determine the cause 1
• Diagnostic paracentesis should be performed without delay in all cirrhotic patients with ascites on hospital admission to rule out SBP 1
• Paracentesis is indicated in patients with signs or symptoms of infection including:
  • Gastrointestinal bleeding 1
  • Shock or fever 1
  • Abdominal pain or tenderness 1
  • Hepatic encephalopathy 1
  • Renal failure or worsening renal function 1
  • Acidosis 1
  • Peripheral leukocytosis without another explanation 1

Initial Ascitic Fluid Analysis

• The initial analysis should include:
  • Total protein concentration and calculation of serum ascites albumin gradient (SAAG) 1
  • Neutrophil count (>250/mm³ is diagnostic of SBP) 1
  • Ascitic fluid culture with bedside inoculation into blood culture bottles 1, 2
• Additional tests based on clinical suspicion:
  • Cytology 1
  • Amylase (when pancreatic disease is suspected) 1
  • Brain natriuretic peptide (BNP) 1
  • Adenosine deaminase 1

Therapeutic Paracentesis Indications

• Therapeutic paracentesis is the first-line treatment for patients with large or refractory ascites 1
• Paracentesis is more effective than diuretics for eliminating ascites (96.5% vs 72.8%) and has fewer complications 3
• Paracentesis should be performed in a single session, draining ascites to dryness as rapidly as possible over 1-4 hours 4

Volume Expansion Guidelines

• For paracentesis >5 liters (large-volume paracentesis):
  • Albumin should be infused at 8g albumin/L of ascites removed 1, 4
  • Use 20% or 25% albumin solution after paracentesis is completed 1, 4
• For paracentesis <5 liters:
  • Synthetic plasma expanders (150-200 ml of gelofusine or haemaccel) are sufficient 1
  • Consider albumin (8g/L) in high-risk patients with acute-on-chronic liver failure or high risk of post-paracentesis acute kidney injury 1, 4

Procedural Considerations

• Ultrasound guidance should be considered when available to reduce the risk of adverse events 1, 5
• Routine measurement of prothrombin time and platelet count before paracentesis is not recommended 1
• Informed consent should be obtained before the procedure 1
• The Z-track technique should be used during insertion to prevent leakage 5
• For leaking paracentesis sites:
  • Have the patient lie on the opposite side for at least two hours 5
  • Consider a purse-string suture around the drainage site for persistent leakage 5

Management of Spontaneous Bacterial Peritonitis (SBP)

• Ascitic neutrophil count >250/mm³ is diagnostic of SBP 1
• Immediate empirical antibiotic therapy should be started when SBP is suspected 1
• Cefotaxime has been widely studied, but antibiotic choice should be guided by local resistance patterns 1
• In patients with SBP and renal impairment, albumin should be administered at 1.5g/kg within 6 hours of diagnosis, followed by 1g/kg on day 3 1
• A second diagnostic paracentesis at 48 hours should be considered in patients with inadequate response or suspected secondary bacterial peritonitis 1

Prophylaxis of SBP

• Patients who have recovered from an episode of SBP should receive prophylaxis with:
  • Norfloxacin (400 mg once daily) 1
  • Ciprofloxacin (500 mg once daily) 1
  • Co-trimoxazole (800 mg sulfamethoxazole and 160 mg trimethoprim daily) 1
• Patients with gastrointestinal bleeding and ascites should receive prophylactic antibiotics 1

Common Pitfalls and Caveats

• Failure to perform diagnostic paracentesis in patients with new-onset ascites or hospitalized cirrhotic patients with ascites can delay diagnosis of SBP 1
• Not inoculating ascitic fluid into blood culture bottles at the bedside reduces diagnostic yield for SBP 1, 2
• Omitting albumin administration after large-volume paracentesis can lead to post-paracentesis circulatory dysfunction, renal impairment, and hepatorenal syndrome 4
• Leaving drains in overnight increases infection risk and should be avoided 4