pneumopericardium
/ˌnjuːmə(ʊ)pɛrɪˈkɑːdɪəm/Medicine
noun
The presence of air or gas in the pericardium. Also (more fully artificial pneumopericardium): the deliberate introduction of air or gas into the pericardium for therapeutic or diagnostic purposes (now rare ).
Origin
Early 19th century; earliest use found in John Forbes (1787–1861), physician and medical journalist. From pneumo- + pericardium, after French pneumo-péricarde.