What is Paracentesis?

Paracentesis is a procedure to remove fluid that has collected in the abdomen. The fluid buildup is called ascites. Ascites may be caused by infection, inflammation, an injury, or other conditions, such as cirrhosis or cancer. The fluid is taken out using a long, thin needle put through the belly. The fluid is sent to a lab and studied to find the cause of the fluid buildup. Paracentesis also may be done to take the fluid out to relieve discomfort due to pressure or pain in people with cancer or cirrhosis.

How to prepare for Paracentesis?

There is no sedation used, so you do not need a driver. It is also not necessary to stop blood thinners or other medications. However, you do need to inform your doctor of all medications you take.

It is recommended that you eat only lightly before the procedure.

Why is it done?

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.

How is it done?

An IV is placed before the procedure. You are asked to lie flat on your back. Ultrasound is used to locate the site for drainage and it is usually in one of the flanks. The area is cleaned and made sterile. A numbing agent (Lidocaine) is then injected into the skin followed by insertion of a long needle into the fluid. This step is painless. The fluid may be drawn with a syringe.

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 5 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 (IV) in a vein in your arm. This fluid is needed to prevent low blood pressure. 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. After the test, your pulse, blood pressure and temperature are watched for about an hour. You may be weighed and the distance around your belly may be measured before and after the test.

Paracentesis takes about 20 to 30 minutes. It will take longer if a large amount of fluid is taken out. You can do your normal activities after the test unless your doctor tells you not to.

You can drive to and back from the procedure since no sedation is being used.

What are the Risks?

There is a very small chance that the paracentesis needle may poke the bladder, bowel, or a blood vessel in the belly. Ultrasound scan is used to accurately locate the fluid and minimize the risk.

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.

Sometimes, the site of the paracentesis may leak small amounts of fluid after you go home. This usually stops in a few hours and if it continues, you may need a small stitch placed at the leak site.