Case study 132 - Anoxic Brain Injury Anoxic brain injuries are caused by a complete lack of oxygen to the brain, which results in the death of brain cells after approximately four minutes of oxygen deprivation. The overall life expectancy for patients with anoxic brain injuries or hypoxic brain injuries can vary based on the severity of the brain damage from lack of oxygen and is something that should be discussed with a patient’s physician. If you don’t know CPR, please consider taking a class