Paracentesis

A paracentesis is a procedure used to drain fluid from the abdomen. It is done by inserting a thin, hollow needle into the peritoneal cavity. A paracentesis may also be called an abdominal tap.

Normally, there is a very small amount of fluid in the peritoneal cavity. This fluid lubricates the surfaces of the organs in the cavity and prevents friction between the organs and the cavity lining. Sometimes a medical problem can cause extra fluid to build up in the peritoneal cavity (called ascites) . This can cause symptoms such as pain, problems breathing or a swollen abdomen.

If you have symptoms of ascites and tests show that there is a buildup of fluid in the abdomen, you may have a paracentesis to remove the fluid and relieve your symptoms. A sample of fluid is sometimes collected for testing. Lab tests can be used to check if the fluid contains cancer cells or if the ascites is caused by a non-cancerous condition.

A paracentesis is usually done as an outpatient procedure. This means that you won’t have to stay in the hospital or clinic overnight. It typically takes about 30 minutes. If a lot of fluid is removed, you may need stay for a few hours to have your blood pressure monitored. If a paracentesis is done as a part of palliative care, you may be able to have the procedure done at home.

You will be awake during the procedure, lying on your back on a bed that has your head slightly raised. You won’t have anything covering your abdomen. You may be asked to urinate (pee) right before so that your bladder is empty.

Your doctor may use an ultrasound to find the best place to insert the needle. After cleaning the skin, your doctor will numb the area with a local anesthetic so that you don’t feel pain. They will insert a thin, hollow needle through the skin and muscles into the peritoneal cavity and then place a flexible tube called a catheter into the site to help the fluid drain. The doctor pulls out the fluid through the catheter using a syringe or tubing connected to a vacuum bottle.

When the extra fluid has been removed, your doctor will take out the catheter and put a bandage over the site. They sometimes send a small amount of fluid to a lab to be tested.

If there is a lot of fluid or your doctor thinks that it will build up again, you may need to have a tunnelled peritoneal drainage catheter put in place. This is a flexible tube that goes under the skin into the peritoneal cavity. The other end is attached to a container outside the body. This long-term solution means you can drain the fluid at home and won’t have to keep going back to the hospital.

Side effects can happen with any procedure. The most common side effect from a paracentesis is discomfort, pain or bleeding where the needle or catheter is inserted. It's also common for a small amount of fluid to leak out from the injection site after the procedure.

Other side effects are rare but may include:

• dizziness or light-headedness, especially if a lot of fluid is removed
• an infection where the needle or catheter is inserted
• injury to the bowel (called a bowel perforation)
• low blood pressure
• kidney failure

Albumin, a protein made by the liver, may be given through a needle into a vein (intravenously or by IV) after a paracentesis. This is done to help prevent low blood pressure.

Any fluid samples collected during the paracentesis will be tested in a lab. The lab results can help your doctor find out what caused the ascites.

Many types of cancer can cause ascites, including ovarian, uterine, cervical, colorectal, stomach, bladder, pancreatic, liver and breast cancer.

Other conditions that can cause ascites include:

• infection of the peritoneum (peritonitis)
• scarring of the liver tissue (cirrhosis) or liver failure

If the results are abnormal, your doctor may recommend more tests, procedures, follow-up care or treatment.

Preparing children for a test or procedure by explaining what will happen during the test, such as what the child will see, feel and hear, can be very helpful. Preparing children before a test or procedure can help lower their anxiety, make them more cooperative and develop their coping skills.

How you prepare your child for paracentesis depends on your child’s age and experience. Find out more about helping your child cope with tests and treatments.