Paracentesis is a procedure to take out fluid that has collected in the belly. This fluid buildup is called ascites. Ascites may be caused by infection, inflammation, an injury, or other conditions, such as cirrhosis or cancer. Paracentesis also may be done to take the fluid out to relieve belly pressure or pain in people with cancer or cirrhosis.

REASONS FOR EXAM

  • Paracentesis may be done to:
  • Find the cause of fluid buildup in the belly
  • Diagnose an infection in the peritoneal fluid
  • Check for certain types of cancer, such as liver cancer
  • Remove a large amount of fluid that is causing pain or difficulty breathing or that is affecting how the kidneys or the intestines (bowel) are working
  • Check for damage after a belly injury

PREPARATION

You will empty your bladder before the procedure. Other blood tests may be done before a paracentesis to make sure that you do not have any bleeding or clotting problems.

THE PROCEDURE

Your doctor puts a numbing medicine into your belly. Once the area is numb, your doctor will gently and slowly put the paracentesis needle in where the extra fluid is likely to be. If a large amount of fluid is present, the paracentesis needle may be hooked by a small tube to a vacuum bottle for the fluid to drain into it.

Generally, up to 4 L of fluid is taken out. If your doctor needs to remove a larger amount of fluid, you may be given fluids through an intravenous line (IV) in a vein in your arm. It is important that you lie completely still during the procedure, unless you are asked to change positions to help drain the fluid.

When the fluid has drained, the needle is taken out and a bandage is placed over the site. Paracentesis takes about 20 to 30 minutes.

RISKS

There is a very small chance that the paracentesis needle may poke the bladder, bowel, or a blood vessel in the belly. If cancer cells are present in the peritoneal fluid, there is a small chance that the cancer cells may be spread in the belly. If a large amount of fluid is removed, there is a small chance that your blood pressure could drop to a low level. This could lead to shock. If you go into shock, IV fluids or medicines, or both, may be given to help return your blood pressure to normal. There is also a small chance that removing the peritoneal fluid may affect how your kidneys work. If this is a concern, IV fluids may be given during the paracentesis.

RESULTS

The fluid taken from your belly will be sent to a lab to be studied and looked at under a microscope. Results will be ready in a few hours.