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Thoracentesis is a procedure that uses a needle to drain fluid from the space around the lungs (called pleural effusion)

It can be caused by many different conditions, including cirrhosis. If you have a pleural effusion, you may have pain or feel short of breath.  Your healthcare team might suggest a thoracentesis to remove a large amount of fluid from around your lungs to make it easier for you to breathe. Or, they might want to collect a fluid sample for testing.

The Procedure

Before your procedure, the doctor or nurse practitioner will check your chest for a good spot to insert the needle. They’ll do this by tapping on your chest or by ultrasound, where sound waves are used to show a picture of the fluid. When they’ve chosen the best spot, they might put freezing medicine under your skin. This will numb the area and should make you more comfortable. You may still feel a very brief, sharp pain during the procedure.

Next, they’ll insert a needle to drain the fluid. If there’s a lot of fluid, they’ll drain it into containers connected to the needle by a small tube. When the fluid has finished draining, they’ll remove the needle and bandage the spot.

After the Procedure

Sometimes, your healthcare team will order a chest x-ray after your procedure to see if there’s any fluid left, or to check for problems. They might also check your fluid to make sure you don’t have an infection. If you have infection, you’ll probably need to be admitted to the hospital for treatment.

If you go home the same day as your procedure, you’ll probably be at the hospital for 2 to 3 hours. But if you need a lot of fluid drained, you’ll probably be admitted to the hospital for a day or 2.

After the procedure, keep your bandage on for 24 hours. Then, if there is no fluid leaking from the needle site, you can remove the bandage and have a shower. You can wash the needle site gently with soap and warm water. You might feel sore for a few days, but you can go back to your normal activities unless your nurse or doctor gives you other instructions.

If you have a pleural effusion, it’s very important to eat less salt. This helps slow down the fluid buildup around your lungs. Some people need a thoracentesis only once. Others need one every week or 2. Your healthcare team will work with you to decide how often is best for you.

Risks and Side Effects

Just like any medical procedure, thoracentesis has risks you should know about. In rare cases, infection, bleeding, or damage to the liver or spleen can happen. Also, there can be a small risk of a partial collapse of the lung. Sometimes, air can enter the space around the lung. This is called a pneumothorax.

If you have trouble breathing after the procedure, or have pain, fever, bleeding, or fluid is leaking from the needle site, call your doctor or nurse or go to the emergency department right away.


The information on this page was adapted (with permission) from the references below, by the Cirrhosis Care Alberta project team (physicians, nurse practitioners, registered nurses, registered dietitians, physiotherapists, pharmacists, and patient advisors).

This information is not intended to replace advice from your healthcare team. They know your medical situation best. Always follow your healthcare team’s advice.


  1. US Department of Veterans Affairs, Veterans Health Administration 
  2. Canadian Liver Foundation
Last reviewed March 15, 2021
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