Mesothelioma is a rare type of cancer that develops in the mesothelium, the lining that surrounds and protects the body's internal organs. One of the most common symptoms of mesothelioma is the accumulation of fluid between the pleural layer lining the lungs, called the visceral pleura, and the pleural layer lining the chest cavity, called the parietal pleura. This fluid puts pressure on the chest and lungs, decreasing the capacity for lungs to expand making it difficult for the patient to breathe. Thoracentesis is a mesothelioma treatment procedure that removes this accumulated fluid from between the pleural layers.
Thoracentesis is often performed as a diagnostic procedure, in which a small amount of fluid is removed and sent to a pathology lab for analysis. Examination of the pleural fluid can help doctors determine the cause of fluid buildup.
A small amount of fluid is normally present between the pleural layers surrounding the lungs. This fluid is produced by pleural cells as a lubricant that helps the pleura to slide smoothly against itself, the chest wall, and the body's internal organs. However, an excess of fluid - called a pleural effusion - is usually a sign of something amiss.
Two types of fluid are seen in a pleural effusion: exudative fluid and transudative fluid. Exudative fluid is cloudy because it contains many cells and proteins, and it can indicate diseases of the pleural mesothelial cells such as mesothelioma. Transudative fluid is the clear fluid normally present between the pleural layers. A pleural effusion of transudative fluid indicates that there is an imbalance in how the body is producing and removing this fluid. This can indicate the presence of other diseases, most notably congestive heart failure, but does not indicate a disease of the pleural mesothelial cells.
Analysis of the effusion fluid is not usually sufficient for mesothelioma diagnosis. In most cases, mesothelioma and other types of cancer that are connected with pleural effusions require biopsies for conclusive diagnosis.
Thoracentesis is commonly used to treat the symptoms caused by pleural effusion. Removal of the excess fluid reduces pressure on the chest and lungs, increases the area available for lung expansion, and improves the patient's ability to breathe. In this case, it is known as a "palliative" procedure, because it treats the patient's symptoms but does not affect the underlying disease.
Occasionally, thoracentesis is performed to prepare a patient for pleurodesis. Pleurodesis is a procedure in which a chemical irritant is inserted between the pleural layers to cause the layers to stick together. This removes the space between the pleural layers so that fluid can no longer accumulate there. Before the chemical irritant can be inserted, the fluid in this space must be removed via the thoracentesis procedure.
How Thoracentesis is Performed
Thoracentesis can be performed as either a bedside or outpatient procedure. In most cases, the patient sits and leans forward with arms and head supported. A local anesthetic is injected into the skin and deeper tissues until the needle reaches pleural fluid. Then the thoracentesis needle is inserted to this depth, which is the space between the pleural layers, and a catheter tube inserted through the needle. The needle is generally removed to reduce the risk of complications.
Fluid drains slowly through the tube and is collected in an attached container. The physician will be careful not to drain fluid too quickly, because rapid fluid removal can cause abnormally low blood pressure and/or fluid build up in the lungs.
Thoracentesis is usually followed by a chest X-ray to verify the amount of fluid removed and to check for complications such as air accumulation in the chest cavity.
Is Thoracentesis for You?
Thoracentesis is a relatively safe and painless procedure that removes the fluid buildup of a pleural effusion. Although thoracentesis does not treat or cure mesothelioma, it can be very helpful for diagnosing the underlying cause of the effusion and for dealing with patients' symptoms. Unfortunately, not every mesothelioma patient is a candidate for thoracentesis. Talk to your doctor to determine whether or not this procedure will be helpful for you.
- National Department of Health and Human Services and National Institutes of Health, National Heart, Lung, and Blood Institute. "What is Thoracentesis? http://www.nhlbi.nih.gov/health/dci/Diseases/thor/thor_whatis.html
- The Ohio State University Medical Center. http://medicalcenter.osu.edu/pdfs/PatientEd/Materials/PDFDocs/diagnost/pulmon/thoracen.pdf
- National Institutes of Health. Medical Encyclopedia: Thoracentesis. http://www.nlm.nih.gov/medlineplus/ency/article/003420.htm
Last modified: February 15, 2010.