ThoracentesisPleural 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:
- You sit on a bed or on the edge of a chair or bed. Your head and arms rest on a table.
- The skin around the procedure site is cleaned. A local numbing medicine (anesthetic) is injected into the skin.
A needle is placed through the skin and muscles of the chest wall into the space around the lungs, called the pleural space. The health care provider may use
to find the best spot to insert the needle.
Ultrasound uses high-frequency sound waves to make images of organs and structures inside the body.
- Fluid is drawn out with the needle.
The fluid may be sent to a laboratory for testing (
pleural fluid analysis
Pleural fluid analysis
Pleural fluid analysis is a test that examines a sample of fluid that has collected in the pleural space. This is the space between the lining of th...
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.
A chest x-ray is an x-ray of the chest, lungs, heart, large arteries, ribs, and diaphragm.
DO NOT cough, breathe deeply, or move during the test to avoid injury to the lung.
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 .
Short of breath
Breathing difficulty may involve:Difficult breathingUncomfortable breathingFeeling like you are not getting enough air
Chest pain is discomfort or pain that you feel anywhere along the front of your body between your neck and upper abdomen.
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 .
A pleural effusion is a buildup of fluid between the layers of tissue that line the lungs and chest cavity.
The test is performed to determine the cause of the extra fluid, or to relieve symptoms from the fluid buildup.
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:
- Liver failure
Heart failure is a condition in which the heart is no longer able to pump oxygen-rich blood to the rest of the body efficiently. This causes symptom...
- Low protein levels
- Kidney disease
- Trauma or post-surgery
- Asbestos-related pleural effusion
- Collagen vascular disease (class of diseases in which the body's immune system attacks its own tissues)
- Drug reactions
- Collection of blood in the pleural space (hemothorax)
Lung cancer is cancer that starts in the lungs. The lungs are located in the chest. When you breathe, air goes through your nose, down your windpipe...
Swelling and inflammation of the pancreas (
Acute pancreatitis is sudden swelling and inflammation of the pancreas.
- Blockage of an artery in the lungs (pulmonary embolism)
underactive thyroid gland
Underactive thyroid gland
Hypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone. This condition is often called underactive thyroid....
If your provider suspects that you have an infection, a culture of the fluid may be done to test for bacteria.
Risks may include any of the following:
A collapsed lung occurs when air escapes from the lung. The air then fills the space outside of the lung, between the lung and chest wall. This bui...
- Respiratory distress
A chest x-ray is commonly done after the procedure to detect possible complications.
Alder EH, Blok BK. Thoracentesis. In: Roberts JR, ed. Roberts and Hedges' Clinical Procedures in Emergency Medicine . 6th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 9.
Chernecky CC, Berger BJ. Thoracentesis - diagnostic. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures . 6th ed. St Louis, MO: Elsevier Saunders; 2013:1068-1070.
Review Date: 8/21/2016
Reviewed By: Denis Hadjiliadis, MD, MHS, Paul F. Harron, Jr. Associate Professor of Medicine, Pulmonary, Allergy, and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.