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 intraabdominal 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.
Abdominal radiographs should be obtained before paracentesis, because air may be introduced during the procedure and may interfere with interpretation. It is unnecessary to perform abdominal ultrasound before paracentesis, except in cases of diagnostic uncertainty. The bladder and stomach may need to be emptied to decrease the risk of perforation of these organs. Other possible complications of paracentesis include 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, and infection.
Most ascetic fluid reaccumulates rapidly. Some expert 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 more than 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.
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 (Figure 1A) and abdominal wall anatomy (Figure 1B) are shown. Prep the skin with povidone-iodine solution, and allow it to dry while applying sterile gloves and a mask. Center the sterile drape about one third of the distance from the umbilicus to the anterior iliac crest. 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.
(1) Insertion sites.
Insert an 18-gauge, 2-inch angiocatheter 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 (Figure 2A). Release the pressure on the skin after the needle enters the peritoneum. Advance the catheter until a “pop” is felt and the catheter penetrates the peritoneum (Figure 2B). Remove the stylette, attach to a Luer-lock 20-mL syringe, and advance the catheter into the abdominal cavity (Figure 2C). 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. Use large Luer-tipped syringes or a syringe and one-way valve or stopcock to remove additional fluid.
(2) Lateral site.
If lavage is desired, such as for detecting hemoperitoneum after trauma, make a 3- to 5-mm skin incision (i.e., large enough to allow threading a lavage catheter) in the midline 5 cm below the umbilicus. In a similar manner to that previously described, insert an 18-gauge needle attached to a 20-mL syringe into the peritoneum while applying slight suction to the syringe. Collect fluid in the syringe as described earlier.
(3) Midline site.
PITFALL: Maintain careful control over the depth of needle penetration to help prevent accidental viscus perforation.
Introduce a guide wire through the needle (Figure 4A). If there is any resistance to the wire's passage, withdraw the wire, and reposition the needle until the wire feeds easily. Remove the needle after about one half of the wire is inserted (Figure 4B). Slide the peritoneal lavage catheter over the wire using a gentle twisting motion (Figure 4C). Remove the wire after the catheter is in the peritoneal cavity. Additional fluid may be aspirated before beginning lavage. Connect the intravenous tubing, and infuse 700 to 1000 mL of Ringer's lactate or normal saline into the abdominal cavity. Clamp the tube, and gently roll the patient from side to side. Then unclamp and connect the tubing to a 1-L vacuum bottle or a syringe with stopcock, and remove the fluid. Adjust the patient's position as necessary to get as much fluid as possible returned.
(4) Peritoneal lavage.
PITFALL: Maintain careful control over the wire to prevent it from slipping into the peritoneal cavity.
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.
(5) Apply direct pressure to the wound after the catheter is removed.
PITFALL: Gauze dressing should be applied when rare, persistent drainage occurs.
INSTRUMENT AND MATERIALS ORDERING
Instruments and materials are available from Arrow Medical Products Ltd.; 2400 Bernville Road, Reading, PA 19605 (phone: 800-233-3187;http://www.arrowintl.com/products/critical_care/). Many kits and supplies from various companies (including Baxter and American Hospital Supply) can be obtained from Cardinal Health, Inc., 7000 Cardinal Place, Dublin, OH 43017 (phone: 800-234-8701;http://www.cardinal.com/) and from Owens and Minor, 4800 Cox Road, Glen Allen, VA 23060-6292 (phone: 804-747-9794; fax: 804-270-7281).
Cappell MS, Shetty V. A multicenter, case-controlled study of the clinical presentation and etiology of ascites and of the safety and clinical efficacy of diagnostic abdominal paracentesis in HIV seropositive patients. Am J Gastroenterol 1994;89:2172–2177.
Guarner C, Soriano G. Spontaneous bacterial peritonitis. Semin Liver Dis 1997;17:203–217.
Gupta S, Talwar S, Sharma RK, et al. Blunt trauma abdomen: a study of 63 cases. Indian J Med Sci 1996;50:272–276.
Halpern NA, McElhinney AJ, Greenstein RJ. Postoperative sepsis: reexplore or observe? Accurate indication from diagnostic abdominal paracentesis. Crit Care Med 1991;19:882–886.
Mansoor T, Zubari S, Masiullah M. Evaluation of peritoneal lavage and abdominal paracentesis in cases of blunt abdominal trauma—a study of fifty cases. J Indian Med Assoc 2000;98:174–175.
Runyon BA. Management of adult patients with ascites caused by cirrhosis. Hepatology 1998;27:264–272.
Stephenson J, Gilbert J. The development of clinical guidelines on paracentesis for ascites related to malignancy. Palliat Med2002;16:213–218.
Thomson A, Cain P, Kerlin P, et al. Serious hemorrhage complicating diagnostic abdominal paracentesis. J Clin Gastroenterol1998;26:306–308.
Watanabe A. Management of ascites: a review. J Med 1997;28:21–30.
Webster ST, Brown KL, Lucey MR, et al. Hemorrhagic complications of large volume abdominal paracentesis. Am J Gastroenterol1996;91:366–368.