Paracentesis Health Article

Definition

Also known as peritoneal tap or abdominal tap, paracentesis consists of drawing fluid from the abdomen through a needle.

Purpose

Although little or no fluid is present in the abdominal (peritoneal) cavity of a healthy man, more than half an ounce may accumulate at certain times during a woman's menstrual cycle. Any cancer that originates in or spreads to the abdomen can result in fluid accumulation (malignant ascites).

Doctors remove fluid (ascites) from the abdomen to analyze its composition and determine its origin, to relieve the pressure and discomfort it causes, and to check for signs of internal bleeding This procedure should be performed whenever an individual experiences sudden or worsening abdominal swelling or when ascites is accompanied by fever, abdominal pain, confusion, or coma.

Paracentesis in cancer patients

When performed on a patient who has been diagnosed with cancer, paracentesis helps doctors determine the extent (stage) of the disease and whether conservative or radical treatment approaches would most effectively relieve symptoms or lengthen survival.

Precautions

Before undergoing paracentesis, a patient must make the doctor aware of any allergies, bleeding problems or use of anticoagulants, pregnancy, or possibility of pregnancy.

Description

Paracentesis is performed in a doctor's office or a hospital. The puncture site is cleansed and, if necessary, shaved. The patient may feel some stinging as a local anesthetic is administered, and pressure as the doctor inserts a special needle (tap needle) into the abdomen. Occasionally, guidance with CT or ultrasound may be used.

When paracentesis is performed for diagnostic purposes, less than an ounce of fluid is drawn from the patient's abdomen into a syringe. As much as 15 ounces may be needed to determine whether ascites contains cancer cells. When the purpose of the procedure is to relieve pressure or other symptoms, many quarts of ascites may be drained from the abdomen. Because removing large amounts of fluid in a short time can cause dizziness, lightheadedness, and a sudden drop in blood pressure, the doctor may drain fluid slowly enough that the patient's circulatory system has time to adapt.

Laboratory analysis of abdominal fluid can detect blood, cancer cells, infection, and elevated protein levels often associated with malignant ascites. Results of these tests can help doctors determine the most appropriate course of treatment for a particular patient.