Introduction and Definition The brain requires a constant flow of oxygen to function normally. A hypoxic-anoxic injury, also known as HAI, occurs when that flow is disrupted, essentially starving the brain and preventing it from performing vital biochemical processes. Hypoxic refers to a partial lack of oxygen; anoxic means a total lack. In general, the more complete the deprivation, the more severe the harm to the brain and the greater the consequences.