What Is Thoracentesis?

Thoracentesis (THOR-a-sen-TE-sis) is a procedure to remove excess fluid in the space between the lungs and the chest wall. This space is called the pleural space.

Normally, the pleural space is filled with a small amount of fluid—about 4 teaspoons full. But some conditions, such as heart failure, lung infections, and tumors, can cause more fluid to build up. When this happens, it’s called a pleural effusion. A lot of extra fluid can press on the lungs, making it hard to breathe.

Overview

Thoracentesis is done to find the cause of a pleural effusion. It also may be done to help you breathe easier.

During the procedure, your doctor inserts a thin needle or plastic tube into the pleural space and draws out the excess fluid. Usually, doctors take only the amount of fluid needed to find the cause of the pleural effusion. However, if there's a lot of fluid, they may take more. This helps the lungs expand and take in more air, which allows you to breathe easier.

After the fluid is removed from your chest, it's sent for testing. Once the cause of the pleural effusion is known, your doctor will plan treatment. For example, if an infection is causing the excess fluid, you may be given antibiotics to fight the infection. If the cause is heart failure, you will be treated for that condition.

Thoracentesis usually takes 10 to 15 minutes. It may take longer if there's a lot of fluid in the pleural space. You will be watched for up to a few hours after the procedure for complications.

Outlook

The procedure usually doesn't cause serious problems, but some risks are involved. These include pneumothorax (noo-mo-THOR-aks), or collapsed lung; pain, bleeding, bruising, or infection where the needle or tube was inserted; and liver or spleen injury (very rare).

Most of these complications get better on their own, or they're easily treated.

December 2007