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Abdominal Paracentesis

E. J. Mayeaux, Jr, MD, DABFP, FAAFP



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Subject: Abdominal Paracentesis

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Abdominal paracentesis is a safe and effective diagnostic and therapeutic procedure used in the evaluation of a variety of abdominal problems, including ascites, abdominal injury, acute abdomen, and peritonitis. Ascites may be recognized on physical examination as abdominal distention and the presence of a fluid wave. Therapeutic paracentesis is employed to relieve respiratory difficulty due to increased intra-abdominal pressure caused by ascites. 
Midline and lateral approaches can be used for paracentesis, with the left-lateral technique more commonly employed. The left-lateral approach avoids air-filled bowel that usually floats in the ascitic fluid. The patient is placed in the supine position and slightly rotated to the side of the procedure to further minimize the risk of perforation during paracentesis. Because the cecum is relatively fixed on the right side, the left-lateral approach is most commonly used. 
Most ascetic fluid reaccumulates rapidly. Some experts recommend that no more than 1.5 L of fluid be removed in any single procedure. Patients with severe hypoproteinemia may lose additional albumen into reaccumulations of ascites fluid and develop acute hypotension and heart failure. Cancer patients with malignant effusions may also need repetitive therapeutic paracentesis. Intravenous fluid and vascular volume support may be required in these patients if larger volumes are removed. 
After diagnostic paracentesis, fluid should be sent to the laboratory for Gram stain; culture; cytology; protein, glucose, and lactate dehydrogenase levels; and blood cell count with a differential cell count. A polymorphonuclear cell count of >500 cells/mm3 is highly suggestive of bacterial peritonitis. An elevated peritoneal fluid amylase level or a level greater than the serum amylase level is found in pancreatitis. Grossly bloody fluid in the abdomen (>100,000 red blood cells/mm3) indicates more severe trauma or perforation of an abdominal organ. The classic positive test for hemoperitoneum is the inability to read newspaper type through the paracentesis lavage fluid. 


Disposable paracentesis/thoracentesis kits usually include the following: 
  • Antiseptic swab sticks

  • Fenestrated drape

  • Lidocaine 1%, 5-mL ampule

  • Syringe, 10 mL

  • 2-inch-long injection needle

  • No. 11 blade scalpel

  • 14-gauge catheter over 17-gauge × 6-inch needle with three-way stopcock or one-way valve, self-sealing valve, and a 5-mL Luer Lock syringe

  • Syringe, 60 mL

  • Tubing set with roller clamp

  • Drainage bag or vacuum container

  • Specimen vials or collection bottles (3)

  • Gauze, 4 inch × 4 inch

  • Adhesive dressing


  • Evaluation of ascites fluid to help determine etiology, to differentiate transudate versus exudate, to detect the presence of cancerous cells, or to address other considerations

  • Evaluation of blunt or penetrating abdominal injury

  • Relief of respiratory distress due to increased intra-abdominal pressure

  • Evaluation of acute abdomen

  • Evaluation of acute or spontaneous peritonitis

  • Evaluation of acute pancreatitis


  • Acute abdomen requiring immediate surgery (absolute contraindication)

  • Severe thrombocytopenia (platelet count <20 × 103/μL)

  • Coagulopathy (international normalized ratio [INR] >2.0)

  • In patients without clinical evidence of active bleeding, routine labs such as prothrombin time (PT), activated partial thromboplastin time (aPTT), and platelet counts may not be needed prior to the procedure.

  • Severe bowel distention (use extra caution)

  • Multiple previous abdominal operations

  • Pregnancy (absolute to midline procedure)

  • Distended bladder that cannot be emptied with a Foley catheter (relative contraindication)

  • Obvious infection at the intended site of insertion (relative contraindication)

  • Severe hypoproteinemia (relative contraindication)

  • Intra-abdominal adhesions

The Procedure

Step 1

The anatomy of the abdominal wall is shown. The insertion sites may be midline or through the oblique transversus muscle, which is lateral to the thicker rectus abdominus muscles. 

Step 2

Empty the patient’s bladder either voluntarily or with a Foley catheter. Place the patient in the horizontal supine position, and tilt the patient slightly to the side of the collection (usually the left lower quadrant). Slightly rotate the hip down on the table on the side of needle insertion to make that quadrant of the abdomen more dependent. The insertion sites are shown. 

Step 3

Prep the skin with povidone-iodine or chlorhexidine solution, and allow it to dry while applying sterile gloves and a mask (see Appendix E: Skin Preparation Recommendations). 
  • Pearl: Prep a wide area so that an undraped area is not inadvertently exposed if the drape slides a little.

Step 4

Center the sterile drape about one third of the distance from the umbilicus to the anterior iliac crest. 

Step 5

Infiltrate the skin and subcutaneous tissues with a 1% solution of lidocaine with epinephrine. A 2-inch needle is then inserted perpendicular to the skin to infiltrate the deeper tissues and peritoneum with anesthetic. 

Step 6

Insert the catheter/introducer through the skin. The nondominant hand then stretches the skin to one side of the puncture site, and the needle is further inserted to create a Z tract. 

Step 7

Advance the catheter until a “pop” is felt and the catheter penetrates the peritoneum. Release the pressure on the skin after the introducer enters the peritoneum. Advance the catheter into the abdominal cavity. 

Step 8

Remove the introducer, and attach the syringe. Draw the fluid into the syringe. If no fluid returns, rotate, slightly withdraw, or advance the catheter until fluid is obtained. If still no fluid returns, abort the procedure, and try an alternative site or method. Ascites fluid may be removed by attaching a three-way stopcock or one-way valve, a 60-cc syringe to one arm, and drainage tubing and bag to the other arm. If lavage is desired, such as for detecting hemoperitoneum after trauma, connect intravenous tubing to the three-way stopcock. Remove excess fluid and then infuse 700 to 1,000 mL of Ringer lactate or normal saline into the abdominal cavity. Gently roll the patient from side to side. Then, remove the fluid as described above or using a trap-suction arrangement. 

Step 9

After the procedure, gently remove the catheter, and apply direct pressure to the wound. Observe the characteristics of the fluid, and send it for the appropriate studies. If the insertion site is still leaking fluid after 5 minutes of direct pressure, suture the site with a vertical mattress suture. Apply a pressure dressing. 
  • PITFALL: Gauze dressing should be applied when rare, persistent drainage occurs.


  • Abdominal radiographs should be obtained before paracentesis, because air may be introduced during the procedure and may interfere with interpretation.

  • Perforation of bladder and stomach (emptied prior to the procedure to decrease the risk)

  • Bowel perforation

  • Laceration of a major blood vessel

  • Loss of catheter or guide wire in the peritoneal cavity

  • Abdominal wall hematomas

  • Pneumoperitoneum

  • Bleeding

  • Perforation of the pregnant uterus

  • Infection

  • Persistent leak from the puncture site

  • Postparacentesis hypotension

  • Dilutional hyponatremia

  • Hepatorenal syndrome

Pediatric Considerations

Pediatric patients may not cooperate with placement of catheter placement. Because of the risks of damage to vessels, nerves, and so forth, consider conscious sedation with intramuscular injections or oral administration of sedating medications such as Versed and Ketamine. 

Postprocedure Instructions

The patient should be instructed to monitor the bleeding of the area and return if any abnormal bleeding is noted. The patient should also be educated to call with questions or concerns regarding pain, numbness, or discomfort in the area. The patient should also monitor for evidence of infection. Lastly, the patient should be advised to clean the area with warm soap and water and pat the area dry. 

Coding Information and Supply Sources

Paracentesis trays that include all instruments needed to perform the procedure can be ordered from the following manufacturers: 


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2008 MAG Mutual Healthcare Solutions, Inc.’s Physicians’ Fee and Coding Guide. Duluth, Georgia. MAG Mutual Healthcare Solutions, Inc. 2007.