In the state of California, patients are said to have suffered anoxic brain injury when their brain has been deprived of oxygen for more than four minutes. If the brain has been deprived of oxygen for five minutes or longer, anoxic brain injury, also called hypoxic-anoxic injury or cerebral hypoxia, can be permanent. This injury is considered life-threatening and can have serious consequences on a survivor’s cognitive abilities.
There are multiple causes of anoxia. These include electrical shock, carbon monoxide inhalation, poisoning, suffocation, illegal drug use and compression of the trachea. There are four types of anoxia;
- Anemia anoxia – This form of anoxia occurs when the blood is not carrying adequate oxygen to the brain. The blood flow to the brain is still adequate, but the lungs are not processing oxygen as they should. Carbon monoxide poisoning is one of the most common causes of anemia anoxia.
- Toxic anoxia – This form is caused by toxins in the system. For example, a buildup of carbon monoxide in a person’s body can cause this type of anoxia.
- Stagnant anoxia – This is also called hypoxicischemic injury or HII. It is an internal condition that blocks oxygen-rich blood from getting to the brain. Strokes and cardiac arrest are the most common causes.
- Anoxic anoxia – This type of anoxia often occurs at high altitudes where there is not enough oxygen in the air.
Anoxia can cause cognitive issues like short-term memory loss, poor performance of executive functions, anomia and visual disturbances. Physical issues caused by anoxia include ataxia, apraxia, movement disorders, weakness in all four limbs, and headaches.
