thoracentesis

n. procedure in which a needle is inserted into the chest cavity in order to aspirate fluids (Medicine)

Thoracentesis (also known as thoracocentesis or pleural tap) is an invasive procedure to remove fluid or air from the pleural space for diagnostic or therapeutic purposes. A cannula, or hollow needle, is carefully introduced into the thorax, generally after administration of local anesthesia. The procedure was first described in 1852.
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Also known as pleural fluid analysis, thoracentesis is a procedure that removes fluid or air from the chest through a [more]Thoracentesis - Community and Resources

(n.)
The operation of puncturing the chest wall so as to let out liquids contained in the cavity of the chest.
  

Removal of fluid in the pleura through a needle.