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Thoracentesis

Pleural fluid aspiration; Pleural tap

Thoracentesis is a procedure to remove fluid from the space between the lining of the outside of the lungs (pleura) and the wall of the chest.

How the Test is Performed

The test is done in the following way:

How to Prepare for the Test

No special preparation is needed before the test. A chest x-ray or ultrasound will be done before and after the test.

How the Test will Feel

You will feel a stinging sensation when the local anesthetic is injected. You may feel pain or pressure when the needle is inserted into the pleural space.

Tell your provider if you feel short of breath or have chest pain, during or after the procedure.

Why the Test is Performed

Normally, very little fluid is in the pleural space. A buildup of too much fluid between the layers of the pleura is called a pleural effusion.

The test is performed to determine the cause of the extra fluid and to relieve symptoms from the fluid buildup.

Normal Results

Normally the pleural cavity contains only a very small amount of fluid.

What Abnormal Results Mean

Testing the fluid will help your provider determine the cause of pleural effusion. Possible causes include:

If your provider suspects that you have an infection, a culture of the fluid may be done to test for bacteria.

Risks

Risks may include any of the following:

Considerations

A chest x-ray or ultrasound is commonly done after the procedure to detect possible complications.

Related Information

Pleural effusion
Heart failure
Cirrhosis
Hemothorax
Pulmonary veno-occlusive disease
Pulmonary embolus
Collagen vascular disease

References

Blok BK. Thoracentesis. In: Roberts JR, Custalow CB, Thomsen TW, eds. Roberts and Hedges' Clinical Procedures in Emergency Medicine and Acute Care. 7th ed. Philadelphia, PA: Elsevier; 2019:chap 9.

Ruhl TS, Good JL. Thoracentesis. In: Fowler GC, Choby BA, Iyengar D, et al, eds. Pfenninger and Fowler's Procedures for Primary Care. 4th ed. Philadelphia, PA: Elsevier; 2020:chap 218.

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Review Date: 7/31/2022  

Reviewed By: Denis Hadjiliadis, MD, MHS, Paul F. Harron, Jr. Professor of Medicine, Pulmonary, Allergy, and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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