Today’s post follows up on one of the first ones on this site, about abdominal paracentesis!

Paracentesis is the process of drawing out fluid from the peritoneum. It is useful for diagnosing ascites when its cause is unclear, and the procedure be used to therapeutically remove large volumes of ascites fluid.

While it is overall a quite safe procedure, the risks of paracentesis include: bleeding, bowel or bladder perforation, persistent ascites fluid leak, infection.

Paracentesis is usually done in a lateral decubitus position (or supine, for large volumes). The level of the ascites fluid is percussed and a needle is inserted in either in the midline (2-3 cm below umbilicus) or lateral lower quadrant (lateral to rectus abdominus muscle, 2-4 cm superomedial to anterior superior iliac spine). This positioning prevents puncture of the inferior epigastric arteries; visible superficial veins and surgical scars should be avoided too. To reduce risk of ascites fluid leak, the needle is inserted either with a z-tracking technique, or at a 45-degree angle.

• Lee SY, Pormento JG. 2009. Abdominal paracentesis and thoracentesis. Surgical Laparoscopy, Endoscopy & Percutaneous Techniques; 19:e32.
• McGibbon A, Chen GI, Peltekian KM, Veldhuyzen van Zanten S. 2007. An evidence-based manual for abdominal paracentesis. Digestive Disease Science; 52:3307.
• Thomson TW, Shaffer RW, White B, Setnik GS. 2006. Paracentesis. NEJM; 355:e21.