Paracentesis is the insertion of a needle into the abdominal cavity for the removal of fluid. Normally, the abdominal cavity contains only a small amount of fluid. However, fluid can accumulate in the abdomen (ascites) in certain circumstances, such as when a person has liver disease, heart failure, a ruptured stomach or intestine, cancer, or a ruptured spleen. A doctor may use paracentesis to aid in diagnosis (for example, to obtain a fluid sample for analysis) or as part of treatment (for example, to remove excess fluid).
Before paracentesis, a physical examination, sometimes accompanied by an ultrasound scan, is done to confirm that the abdominal cavity contains excess fluid. Next, an area of the skin, usually just below the navel, is washed with an antiseptic solution and numbed with a small amount of anesthetic. A doctor then pushes a needle attached to a syringe through the skin and muscles of the abdominal wall and into the area of fluid accumulation. The needle is used to remove a small amount of fluid for laboratory testing, or a thin tube is used to remove up to several quarts of fluid to relieve swelling (distention) of the abdomen.
Complications of paracentesis include perforation of the digestive tract, leakage of fluid through the hole made by the needle, and bleeding.