Hypoxia and Brain Injury

Hypoxia also called cerebral hypoxia occurs when the available oxygen needed to sustain life drops below the required level. Hypoxic brain injury is caused by a decrease in the supply of oxygen going to the brain. It differs from anoxic brain injury because anoxia means there is no oxygen going to the brain. That does not mean that a hypoxic brain injury is any less severe.

Patients must still be ventilated and other life-saving measures must be taken. Hypoxia can cause coma, seizures and, even, brain death. A major consideration with hypoxia will be how long the brain did not receive an adequate supply of oxygen, and that is, in many cases, unknown.

Various factors can create conditions where hypoxia can take place. For example, if someone suffers from anemia, there’s a shortage of oxygen in the blood so inadequate amounts of oxygen are supplied to the brain. In high altitudes where the air is thinner, the reduced partial pressure of oxygen can also bring about hypoxia. If the supply of blood and thus oxygen to the brain is limited due to a blockage, hypoxia may result. Additionally, respiratory failure, blood pressure drops, head trauma, suffocation, carbon monoxide poisoning, and heart attacks can all reduce oxygen supply to the brain.

Brain cells can begin to die within five minutes after oxygen to the brain has been deprived. If hypoxia lasts for longer than five minutes, coma, seizures, and even brain death may result. When the brain dies, no activity is measured in the brain.

Because the onset of hypoxia is so subtle, it’s essential to notice these symptoms:

  • Dizziness
  • Headache
  • Nausea
  • Fatigue
  • Rapid breathing
  • Loss of coordination
  • Hot and cold flashes
  • Visual difficulties
  • Inattentiveness

The severity of the effect of hypoxia on the brain is determined by how long the brain was deprived of oxygen. The cause of the hypoxia will also determine the seriousness and length of the resulting dysfunction. More traumatic causes like choking, strangulation, or near-drowning will necessitate more time and effort for treatment to restore the patient to full or at least partial functioning.

The recovery and rehabilitation of patients highly depend on the duration of oxygen deprivation the brain endured and on how much degeneration of brain cells occurred. Most patients who had suffered from hypoxia and recovered fully had only been unconscious for a short time. If they had been unconscious for a longer period of time, the chance of brain death or even death resulting from the episode is reasonably higher and the chance of full recovery lower.

In the majority of cases, there are no long term effects. In more severe cases, if the brain injury is in just one or several areas of the brain, the individual will have dysfunctions relating to those areas only, but may be otherwise functional. Partial effects may be speech or motor impediments or some paralysis. During the recovery period, various physical and psychological challenges may appear and later disappear, such as amnesia, muscle spasms, and hallucinations.