What is "hypercapnia"

n. (context medicine English) the condition of having an abnormally high concentration of carbon dioxide in the blood

n. the presence of an abnormally high level of carbon dioxide in the circulating blood [syn: hypercarbia] [ant: hypocapnia]

Hypercapnia, also known as CO2 retention, hypercapnea, and hypercarbia, is a condition of abnormally elevated carbon dioxide (CO) levels in the blood. Carbon dioxide is a gaseous product of the body's metabolism and is normally expelled through the lungs.

Hypercapnia normally triggers a reflex which increases breathing and access to oxygen, such as arousal and turning the head during sleep. A failure of this reflex can be fatal, for example as a contributory factor in sudden infant death syndrome.

Hypercapnia is the opposite of hypocapnia, the state of having abnormally reduced levels of carbon dioxide in the blood. The word is from the Greek hyper = "above" or "too much" and kapnos = " smoke".