The Mesothelioma SOS Glossary - Thoracentesis

Thoracentesis is an invasive surgical procedure that is performed to remove fluid from the pleural cavity, either for diagnostic or therapeutic purposes. Thoracentesis is performed under local anesthetic, and is done with a long hollow needle, or cannula. The cannula is introduced into the thorax, and fluid is drained into a vacuum bottle. This procedure can be done either to analyze the pleural fluid removed for infection or cancer, or it can be performed to release fluid that has accumulated in order to relieve symptoms. Fluid removed is interpreted as either transudate or exudate, and is an important diagnostic tool used by doctors to determine the etiology of pleural fluid. Exudate fluids indicate infection, inflammation, malignancy, and lymphatic disorders. Transudate fluids indicate congestive heart failure, cirrhosis, peritoneal dialysis, and vena cava superior obstruction. The fluids are identified as transudate or exudate by testing the total proteins, the fluid serum ratio, and absolute fluid versus the normal serum level.