A collection of fluid and gas within the pleural cavity. ... (12 Dec 1998) ... 
(hi″dro-noo″mo-thor´aks) a collection of fluid and gas within the pleural cavity; called also pneumohydrothorax.
Type: Term Pronunciation: hī′drō-nū′mō-thōr′aks Definitions: 1. The presence of both gas and fluids in the pleural cavity. Synonyms: pneumohydrothorax, pneumoserothorax