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Practice Guideline Highlights in Gastroenterology
Diagnostic Paracentesis
· All patients with ascites need an immediate diagnostic paracentesis upon presentation.
· Diagnostic paracentesis is a safe procedure even with thrombocytopenia and a prolonged prothrombin time.1,2
· Fluid analysis includes:
1. Cell count with differential (purple top tube)
2. Total protein and albumin (red top tube)
3. Gram stain(red top tube)
4. Culture (aerobic and aerobic culture bottles)
· To calculate the serum-ascites albumin gradient (SAAG) a serum albumin should obtained at the same time as the paracentesis.
· Cultures should be inoculated at the bedside with 10cc of ascitic fluid into each anaerobic and aerobic blood culture bottles.3
· If peritoneal carcinomatosis is suspected, then additional fluid can be obtained for cytology.
The 2 most common locations for obtaining fluid include the midline (ML) halfway between the umbilicus and symphysis pubis and the left lower quadrant (LLQ) 2 fingerbreadths cephalad and 2 fingerbreadths medial from the anterior superior left iliac spine4. The LLQ has been shown to be a better site for performing a paracentesis than the ML4.
After obtaining proper consent from the patient, the area in the LLQ described above should be marked and the patient be positioned at 30-450 in the bed. The marked area should be percussed to ensure dullness and the presence of fluid. It may be helpful to roll the pt in a left lateral oblique position. The area should be prepped and procedure performed using sterile technique.
A paracentesis/thoracentesis tray is usually not necessary for a diagnostic paracentesis. A 30-60cc syringe with a 2” 20-22 gauge needle is all that is required. The needle should be inserted through the skin into the abdominal wall with tension held until fluid is aspirated. Once 30cc of fluid is obtained the physician can stop and withdraw the needle.
· A PMN count > 250 is diagnostic of infection and empiric antibiotics should be started.
· SAAG is calculated by subtracting the ascites from the serum albumin level. If the result is > 1.1, portal hypertension is present. If the SAAG is < 1.1 portal hypertension is not the likely cause of ascites.
· An ascites fluid total protein >2g/dl indicates low likelihood of spontaneous infection. If the ascites total protein is < 1.5 and the PMN count is negative for infection these patients still need prophylactic antibiotics during hospitalization.
The AASLD management guidelines for the evaluation and treatment of patients with ascites are available online through the AASLD website.
The cited publication and link to this article:
Runyon, BA. Management of Adult Patients with Ascites Due to Cirrhosis. Hepatology. 2004 Mar;39(3):841-56. https://www.aasld.org/eweb/docs/practiceguidelines/ascites.pdf
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