Abdominal paracentesis is a simple bedside or clinic procedure in which a needle is inserted into the peritoneal cavity and ascitic fluid is removed. Diagnostic paracentesis refers to the removal of a small quantity of fluid for testing. Therapeutic paracentesis refers to the removal of 5 liters or more of fluid to reduce intra-abdominal pressure and relieve the associated dyspnea, abdominal pain, and early satiety.
There are several generally accepted indications for paracentesis:
•Evaluation of new onset ascites.
•Testing of ascitic fluid in a patient with preexisting ascites who is admitted to the hospital, regardless of the reason for admission.
•Management of tense ascites, or ascites that is diuretic-resistant.
•Evaluation of a patient with ascites who has signs of clinical deterioration, such as fever, abdominal pain/tenderness, hepatic encephalopathy, peripheral leukocytosis, deterioration in renal function, or metabolic acidosis.
The benefits of abdominal paracentesis in patients with appropriate indications almost always outweigh the risks. There are some relative contraindications to paracentesis, though in most cases steps can be taken to allow for paracentesis, even in the setting of a relative contraindication.
Relative contraindications include:
•Clinically apparent disseminated intravascular coagulation
•Primary fibrinolysis
•Massive ileus with bowel distension
•Surgical scars at the proposed paracentesis site
An elevated international normalized ratio or thrombocytopenia is not a contraindication to paracentesis, and for most patients, transfusion of blood product before paracentesis is discouraged since it is not supported by the available data, can delay the procedure, exposes the patient to risk of transfusion, and is costly. Exceptions are patients with clinically apparent disseminated intravascular coagulation or clinically apparent hyperfibrinolysis, who do require treatment to decrease their risk of bleeding.
Proper technique is important to decrease the risk of sample contamination and complications. In particular, proper Z-track technique minimizes the chance of an ascitic fluid leak, the most common complication of paracentesis. Other complications are much less common.
Testing for cell count and differential should be performed on all specimens, even scheduled therapeutic paracenteses.