Tuesday, January 18, 2011
Diagnostic paracentesis is a simple bed side procedure. The basic items needed are a 60 cc syringe, 10 cc syringe, chloraprep, 18 gauge needle, 22 gauge needle, sterile gloves, ultrasound, lidocaine bottle, cap, and mask. Find a safe area to draw peritoneal fluid on the abdomen. The left lower quadrant or right lower quadrant can be used. The largest risk of a diagnostic paracentesis is bowel perforation with the sharp needles. The left lower quadrant is preferred by some since the cecum is prominent in the right lower quadrant. After finding an appropriate area with the ultrasound, sterilize the area and inject with lidocaine. Inject a wheal superficially with a 10 cc syringe and 22 gauge needle. Then inject perpendicularly deeper into the tissue beyond the muscle layers. Always apply negative pressure before injecting to avoid hitting a vein. The needle should advance into the peritoneum and ascites should be aspirated. Inject the lidocaine into the peritoneal area and inject along the pathway as the needle is pulled out. Use the 18 gauge and 60 cc syringe to aspirate the ascites along the anesthetized pathway. Obtain 60 ccs of fluid. Diagnostic paracentesis fluid should be sent for the following tests: cell count and differential, culture, albumin, and total protein. The most important initial test is cell count and differential. If the product of WBC count and segment percentage is greater than 250, then the patient has spontaneous bacterial peritonitis and needs to be treated with intravenous antibiotics. One option is Ceftriaxone. Cultures will provide specific microbe identification and antibiotic sensitivity. Albumin and protein can also help to identify the etiology of ascites, usually differentiating cardiac from hepatic sources. A diagnostic paracentesis is often important and mandatory for all patients admitted with ascites.