Anoxia is defined, as the total absence of oxygen and it is not a pathological condition. Strictly, there can never be a total absence of oxygen, even after death, but the term is often used to mean severe hypoxia or lack of oxygen. The most vulnerable organ in the body is the brain and when the brain is deprived of sufficient oxygen, there are a number of consequences, which depend on the reason for the deprivation, its level, and its duration. The pathology is well described and may include changes, which are reversible, but also some that are not.

Dr Philip B James MB ChB DIH PhD FFOM
Wolfson Hyperbaric Medicine Unit
University of Dundee