General Considerations

Indications:

• Diagnostic: to determine etiology of ascites or rule-out SBP in known ascites.
• Therapeutic: to relieve symptoms of abdominal pain, distension, or dyspnea.

Contraindications:

• Absolute:
  • Cellulitis, herpes zoster, scar, hernia or vessels (i.e. caput medusea) over entry site.
• Relative:
  • Consider reversing coagulopathy if INR >2 (or >3 in patients with cirrhosis) and/or platelets <30K for a standard paracentesis; no cutoffs for a modified paracentesis (using a smaller angiocatheter without scalpel incision).
  • Worsening renal failure for therapeutic paracentesis.
  • Distended bowel, ileus, bowel obstruction, or pregnancy (in the absence of ultrasound as these conditions may be confused for ascites).

Technique

Preparation:

• Obtain informed consent.
• Review procedure with your supervisor and watch the NEJM “Paracentesis” video.
• Gather supplies:
  • Diagnostic: marking pen or temp probe cover, chlorohexidine, 10mL 1% lidocaine, 10mL syringe for lidocaine, 25g needle, 22g needle, 60mL syringe for fluid collection, 1 lavender tube, 1 gold tube, 1 black top tube, 2 orange top tubes (cytology), 2 blood culture bottles, blood transfer device, sterile gauze, Tegaderm, 2 sets of sterile gloves, 2 face masks with eye shields, chuck, wastebasket, ultrasound with abdominal and vascular probes.
  • Therapeutic: marking pen or temp probe cover, paracentesis kit, 15g Caldwell needle if desired (need to order separately), vacutainer bottles (1-8), 2 blood culture bottles, blood transfer device, 2 sets of sterile gloves, 2 face masks with eye shields, sterile gauze, Tegaderm, chuck, wastebasket, ultrasound with abdominal and vascular probes.
• Hold therapeutic enoxaparin for 12 hours and therapeutic heparin for 4 hours prior.
• Have the patient to urinate to empty the bladder.
• Place the patient in a semi-recumbent position (30˚) and percuss the level of dullness. Acceptable insertion areas include midline, RLQ and LLQ. Midline insertion is 2cm below umbilicus (caution in patients with cirrhosis as may have a recanalized umbilical vein).
• Lateral insertion points are 2-4cm medial and cephalad to anterior superior iliac spine. The LLQ is preferred in obese patients as abdominal wall is thinner with a larger fluid pocket.
• Perform bedside ultrasound using the abdominal probe to locate a safe pocket of ascitic fluid (>2cm). Use the vascular probe to ensure there are no overlying subcutaneous blood vessels. Mark the needle entry with a marking pen or temp probe cover.
• If ascites is small on bedside ultrasound, consider consulting IR to do the paracentesis.

Procedural steps:

• Perform Time-Out. Complete and have an assistant co-sign the pre-procedure checklist.
• Ask about allergy to iodine prior to prep. Prep the area with chlorhexidine or betadine.
• Drape the area in sterile fashion and make sure you have all supplies ready, positioned optimally, and in order of use.

• Draw 10mL of 1% lidocaine in a small syringe. Use a 25g needle for the initial wheal and subcutaneous anesthesia. Using a 22g needle, insert the needle perpendicular to the patient and anesthetize all the way to peritoneum. When you obtain peritoneal fluid, note depth of needle.
• For diagnostic paracentesis: use a 20g angiocath attached to 60mL syringe to aspirate ascitic fluid. Remember to continuously aspirate and pull at least 50mL.
• For therapeutic paracentesis: make a small puncture at site of insertion with a scalpel. Attach a small (10mL) syringe to the Caldwell needle and insert needle at insertion site. Slowly advance needle while aspirating until ascitic fluid fills the syringe. Advance the catheter and needle another 0.5cm forward before then keeping the needle still and advancing the catheter over the needle until hubbed. Remove the needle/ syringe. Attach the non-collapsible tubing to the stopcock and then drain fluid in a vacutainer.

Post-Procedure

• Albumin repletion:
  • Post-paracentesis albumin is not necessary for removal of <5L. For ≥5L removed, albumin replacement can be given. The AASLD Class IIA recommendation is 6-8 grams of albumin for every liter removed (~1 bottle of 50cc of 25% IV albumin per 2 liters of ascites).
• Complications:
  • Abdominal wall hematoma, infection (peritonitis), ascitic leakage, perforated viscous, bladder perforation, laceration of abdominal organs, hemorrhage, renal failure, hypotension.

Diagnostic Studies

• Send fluid for cell count/differential (lavender top), albumin and total protein (gold top), and culture (2 culture bottles). Gram stain (black top) is generally unhelpful unless secondary peritonitis is suspected. 
• Other studies (amylase, cytology, AFB, etc.) only if clinically indicated.
• Send simultaneous serum albumin to calculate a SAAG gradient: subtract the ascitic fluid albumin value from the serum albumin value.
• Tips:
  • SBP diagnosed with >250 PMNs (sensitivity 80-100%, specificity 86-100%).
  • A SAAG ≥1.1 g/dL (11 g/L) is indicative of portal hypertension with 97% accuracy.
  • To correct for a traumatic tap, subtract 1 PMN (not WBC) per 250 RBCs. 

Moore KP, Aithal GP. Guidelines on the management of ascites in cirrhosis. Gut 2006;55 Suppl 6:vi1-12.

Runyon BA, AASLD Practice Guidelines Committee. Management of adult patients with ascites due to cirrhosis: update 201.2 Hepatology 2013;57:1651-53.

Thomsen TW, Shaffer RW, White B, Setnik GS. Videos in clinical medicine: Paracentesis. N Engl J Med 2006;355(19):e21.