(Pleural Fluid Aspiration; Pleural Tap)
by Cynthia M. Johnson, MA
Thoracentesis is the removal of excess fluid from the space between the lungs and the chest wall (pleural space).
Reasons for Procedure
This procedure is done to ease or test for the cause of pleural effusion. This is a buildup of fluid in the pleural space that can make it hard to breathe.
The fluid may be tested to look for signs of health problems, such as:
Problems are rare, but all procedures have some risk. The doctor will go over some problems that could happen, such as:
Things that may raise the risk of problems are:
What to Expect
Prior to Procedure
The surgical team may meet with you to talk about:
A local anesthetic will be used. It will numb the area where the needle will be inserted.
Description of the Procedure
You will sit upright on the edge of a bed or chair. Your arms will be resting on a nearby table. A needle or thin plastic catheter will be inserted between the ribs. An ultrasound or CT scan may be used to guide the needle and monitor the fluid. The needle or catheter is then passed into the pleural space. Some or most of the fluid will be drawn into the syringe. The needle or catheter will be removed. A bandage will be placed over the site.
How Long Will It Take?
About 15 minutes
Will It Hurt?
You may feel slight pain or a stinging when the needle is inserted. You may feel a sense of pulling when the fluid is removed.
At the Care Center
The fluid may be sent to a lab for testing. Another image may be taken to make sure your lungs are working well.
Physical activity may be limited for a few days.
Call Your Doctor
Call your doctor if you are not getting better or you have:
If you think you have an emergency, call for medical help right away.
American Lung Association
American Thoracic Society
The Canadian Institutes of Health Information
The Lung Association
How to Do Thoracentesis. The Merck Manual Professional Edition website. Available at:
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Updated June 2019. Accessed May 5, 2020.
Thoracentesis. American Thoracic Society. Available at: https://www.thoracic.org/patients/patient-resources/resources/thoracentesis.pdf. Updated February 2016. Accessed May 5, 2020.
Thoracentesis. EBSCO DynaMed website. Available at: https://www.dynamed.com/procedure/thoracentesis. Updated March 25, 2020. Accessed May 5, 2020.
Thoracentesis. Johns Hopkins Medicine website. Available at:
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Accessed May 5, 2020.
Thoracentesis. National Heart Lung and Blood Institute website. Available at: https://www.nhlbi.nih.gov/health/health-topics/topics/thor. Accessed May 5, 2020.
Last reviewed February 2020 by EBSCO Medical Review Board Daniel A. Ostrovsky, MD
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