Paracentesis Technique

Advanced Ultrasound Techniques

Step by Step Instructions


Tips and Tricks

Diagnostic versus therapeutic paracentesis

  • Diagnostic paracentesis saves time
    • Once lidocaine needle enters the ascites, simply unscrew the lidocaine syringe, and screw on a 20ml syringe to aspirate diagnostic fluid
      • Preservatives in the Lidocaine syringe may interfere with analysis of ascites fluid and culture results
  • Diagnostic paracentesis may reduce complications
    • The single pass of the small 22 gauge needle may reduce bleeding and ascites fluid leakage

Inoculate blood culture bottles at the bedside

  • Waiting for the lab to inoculate culture bottles reduces the sensitivity of SBP by 25%1
  • Always obtain aerobic and anaerobic blood cultures (+/- fungal culture) bottles from the nursing supply room prior to the procedure
  • Wipe the tops of the bottle with an alcohol swab and inject 8-10ml into each


  • Not mandatory, but generally considered the standard of care for paracentesis2
    • US increases success rate from 65% -> 95%3
    • US decrease bleeding complications4
  • Tips
    • Locate largest fluid pocket5
      • At least 3cm
      • For small fluid pockets use a sterile probe cover and follow the needle in real-time to ensure safe entry into ascites
    • After marking the skin don’t let the patient move prior to needle insertion
      • Small movements can change the bowel location in relation to the skin markings above
      • If the patient moves, reconfirm your insertion site with US
      • A sterile probe cover should be used if the area has been sterilized
    • Wipe off the Gel
      • Surgical markers and sharpies immediately stop working when they come into contact with US gel
      • Use a hand towel to wipe off the gel prior to marking the skin

Poor flow of ascites

  • During aspiration, small bowel or omentum can occlude the bevel or the catheter ports
  • To improve flow
    • Roll the patient towards the side of needle insertion to increase pooling of fluid around the needle
      • Pillows are helpful to support them in this position
    • Pushing on the abdominal wall can increase the flow of ascites
    • Briskly injecting a 10ml normal saline flush can push away loops of bowel
    • Slowly withdrawing the catheter to pull it away from loops of bowel may also help flow

Don’t let the lab throw away your specimen

  • The lab is mandated to dispose of improperly labeled specimens
  • Place a patient sticker on ALL tubes of ascites including blood culture bottles
    • Mark them with you initials, date, and time


  1. Runyon, B.A. Management of adult patients with ascites due to cirrhosis: an update. Hepatology 49, 2087-107 (2009).
  2. Thomsen, T.W., Shaffer, R.W., White, B. & Setnik, G.S. Videos in clinical medicine. Paracentesis. N Engl J Med 355, e21 (2006).
  3. Nazeer, S.R., Dewbre, H. & Miller, A.H. Ultrasound-assisted paracentesis performed by emergency physicians vs the traditional technique: a prospective, randomized study. Am J Emerg Med 23, 363-7 (2005).
  4. Mercaldi, C.J. & Lanes, S.F. Ultrasound guidance decreases complications and improves the cost of care among patients undergoing thoracentesis and paracentesis. Chest 143, 532-8 (2013).
  5. Scheer, D., Secko, M. & Mehta, N. ACEP.–Ultrasound-Guided-Paracentesis (November, 2012).