Reviewed by: HU Medical Review Board | Last reviewed: January 2017.

Thoracentesis is a procedure in which a needle or small tube is used to remove excess fluid in the pleural space, the space between the lungs and the chest wall. Fluid can build up as a result of lung cancer, as well as from other conditions like infections, injury, heart or liver failure, or blood clots in the lungs. This fluid build-up is called pleural effusion, and while some people experience no symptoms with pleural effusion, others experience chest pain that may worsen with deep breathing or coughing, dry cough, shortness of breath, difficulty breathing, rapid breathing, fever, or hiccups. When fluid occupies the pleural space, the lungs do not have space to properly inflate. Removing the fluid helps the patient to breathe easier.1-3

Thoracentesis can be used both to remove the fluid and determine the cause of the fluid build-up. After the fluid is removed, a laboratory may examine the fluid. Thoracentesis can be one of the procedures used to assist a physician in diagnosing lung cancer.4

About the Procedure

Prior to the procedure, ultrasound or chest x-ray may be used to determine the presence and size of pleural effusion. Ultrasound may also be used during the procedure to guide the needle.4,5

The patient is given local anesthetic to numb the area where the needle or tube will be placed. Some patients may also be given mild sedation through an IV (intravenous) line to treat anxiety related to the procedure. The patient will be awake during the procedure and is advised not to move, cough or breathe deeply during the test.4,5

Thoracentesis is a common procedure and is generally safe. Possible risks of thoracentesis include bleeding, infection, collapsed lung (pneumothorax), or respiratory distress.4,5

Following thoracentesis, the patient should be able to breathe easier.4,5

Other Tests Used to Diagnose Lung Cancer

Thoracentesis is one procedure that may contribute to the diagnosis process of lung cancer. Other tests that may be used include chest x-ray, CT (computed tomography) scans, PET (positron emission tomography) scans, laboratory tests, sputum cytology, needle biopsy, bronchoscopy, thoracoscopy, and pulmonary function testing.

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