(Pleural Fluid Aspiration; Pleural Tap)
by Amanda L. Dameron, MA
A pleural effusion is a build-up of fluid in the space between the lungs and the chest wall. This space is called the pleural space. Thoracentesis is a procedure to remove fluid from this area.
There are two types of thoracentesis:
Reasons for Procedure TOP
There is always a small amount of fluid in the pleural space. The fluid helps to lubricate the area. When too much fluid builds up in this space, it can make it difficult to breathe.
Your doctor may want to test some of the fluid after removing it. The build-up of fluid can be a symptom of diseases or disorders, such as:
Possible Complications TOP
Complications are rare, but no procedure is completely free of risk. If you are planning to have a thoracentesis, your doctor will review a list of possible complications, which may include:
Factors that may increase the risk of complications include:
What to Expect TOP
A local anesthetic will be used. It will numb the area where the needle will be inserted.
Description of the Procedure TOP
You may be asked to sit upright on the edge of a bed or chair. Your arms will be resting on a nearby table. If your procedure involves a CT scan, you may be asked to lie on a table. Try to avoid coughing, breathing deeply, or moving during the procedure.
A small patch of skin on your back, chest, or under your armpit will be sterilized. Anesthesia will be applied to this patch. It will help numb the area.
The doctor may use ultrasound or CT scan images to guide the needle and monitor the fluid. A needle or thin plastic catheter will be inserted between your ribs. The needle or catheter is then passed into the pleural space. Some or all of the fluid will be drawn into the syringe.
How Long Will It Take? TOP
About 15 minutes
Will It Hurt? TOP
You may feel slight pain or a stinging when the needle is first inserted. As the fluid is being extracted, you may feel a sense of pulling. Tell your doctor or nurse if you feel extreme pain, any shortness of breath, or faint.
Post-procedure Care TOP
At the Care Center
If the thoracentesis is being done for diagnostic reasons, the fluid will be sent to a lab for testing. Often, another chest x-ray will be done to ensure that the fluid has been removed and that there is no sign of a collapsed lung.
The doctor may begin treatment for the cause of the fluid build-up.
Keep the area of skin where the needle was inserted clean and dry. To help make your recovery smooth, be sure to follow your doctor's instructions.
If a diagnostic thoracentesis was done, ask your doctor when to expect the results.
Call Your Doctor TOP
After arriving home, contact your doctor if any of the following occurs:
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 Canadian Lung Association
Harrison’s Principles of Internal Medicine . 16th ed. McGraw-Hill; 2005.
Mason RJ. Murray & Nadel's Textbook of Respiratory Medicine . 4th ed. WB Saunders; 2005.
Roberts JR. Clinical Procedures in Emergency Medicine . 4th ed. WB Saunders; 2004.
What is thoracentesis? National Heart, Lung, and Blood Institute website. Available at:
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Updated February 24, 2012. Accessed April 10, 2013.
6/3/2011 DynaMed's Systematic Literature Surveillance
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: Mills E, Eyawo O, Lockhart I, Kelly S, Wu P, Ebbert JO. Smoking cessation reduces postoperative complications: a systematic review and meta-analysis.Am J Med. 2011;124(2):144-154.e8.
Last reviewed February 2014 by Michael Woods, MD
Last Updated: 3/15/2013