Oxygen is crucial to the brain as it is used to metabolise glucose, which provides energy for all body cells. Brain cells are sensitive to the effects of restricted oxygen supply and can die within minutes of oxygen restriction. The immediate outcome of severe oxygen restriction is often coma and in very severe cases brain death.
- near drowning
- drug overdose
- severe asthma
- accidents involving anaesthesia
- carbon monoxide inhalation and poisoning
- heart attack
Hypoxia can also occur as a secondary injury following a traumatic brain injury, e.g. when there is serious blood loss resulting in low blood pressure, or as a result of brain swelling that restricts oxygen supply to areas of the brain.