Hypoxic brain injury or cerebral hypoxia is a condition that refers to a severe decrease of oxygen supplied to the brain, even though there is sufficient blood flow. This condition may be caused by a blockage in the respiratory tract or airways brought about by strangling, suffocation or choking, conditions such as head trauma, cardiac arrest, carbon monoxide poisoning and complications from surgery. In mild cases, cerebral hypoxia can lead to memory loss or temporary amnesia, poor judgment, impaired motor coordination and inattentiveness or carelessness.

It is very important for the brain to have adequate supply of oxygen. Oxygen deprivation in brain cells can lead to tragic consequences within minutes. If the lack or absence of oxygen lasts longer, the brain cannot respond to stimuli, which leads to seizures, unconsciousness, coma and brain death. When brain death happens, basic life functions such as breathing, homeostasis, blood circulation and maintenance of blood pressure, along with other cardiac functions are preserved, but then the patient would already be unresponsive and unconscious of everything.

Treatments greatly depend on the primary cause of the hypoxia, but is imperative that basic life-support systems have to be installed in order to regulate the body's processes. For example, a ventilator is needed to secure the airway; medications to maintain blood pressure and heart rate; and other medicines to suppress seizures that can further damage brain tissues.

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.