Symptoms of mild brain damage from a lack of oxygen, or cerebral hypoxia, include short attention span, poor coordination and faulty judgment, according to MedlinePlus. Signs of more serious cerebral hypoxia are coma, inadequate pupil response to light and suspension of breathing.
Lack of oxygen begins killing brain cells within five minutes, states MedlinePlus. Re-establishing the oxygen supply to the brain helps limit the damaging effects. Treatment often consists of using mechanical ventilation, stabilizing regular heart rhythm and medicating to reduce seizures. In addition, blood pressure is often low, so drugs, fluids or additional blood is prescribed.
Cerebral hypoxia is sometimes caused by smoke inhalation, carbon monoxide poisoning, drowning or high altitude, MedlinePlus lists. Oxygen is cut off during traumatic incidents such as choking, pressure on the windpipe, drug overdose, injury during birth and strangulation. ALS and other diseases paralyze breathing muscles, resulting in oxygen deprivation. Cardiac arrest, arrhythmia, extremely low blood pressure and stroke sometimes stop the flow of oxygen. In certain surgical cases, complications from general anesthesia lead to cerebral hypoxia.
The severity of brain damage is typically determined by the amount of time the brain was missing oxygen and if other nutrients were cut off as well, explains MedlinePlus. Some patients recover fully, while others are left with twitching motions or seizures. However, long periods of oxygen deprivation often end in death.