Cerebral hypoxia occurs when your brain doesn’t get enough oxygen. A related condition, anoxia, occurs when no oxygen reaches the brain. Healthcare providers often use the terms together: a hypoxic-anoxic brain injury.
Without oxygen, brain cells die, and a brain injury can occur. It can happen even when enough blood reaches the brain, such as when you breathe in smoke or carbon monoxide.
Treatments can help people who have brain injuries from cerebral hypoxia. But no one can bring back dead brain cells or reverse a brain injury. The condition can result in lifelong brain damage. If it continues too long, it can be fatal.
Your brain runs your nervous system. It needs oxygen to function. In fact, the brain uses about a fifth of your body’s total oxygen supply. Oxygen helps send nerve signals and messages throughout the body.
When the brain doesn’t get enough oxygen, brain cells begin to die. Cell death happens within 5 minutes of low oxygen.
Many things can affect oxygen flow to the brain, including:
A person experiencing cerebral hypoxia may:
People who recover from cerebral hypoxia may have lifelong problems, such as:
Severe oxygen deprivation can cause life-threatening problems including coma and seizures.
After 10 minutes without oxygen , brain death occurs. Brain death means there is no brain activity. A person needs life support measures like a mechanical ventilator to help them breathe and stay alive.
A healthcare provider may order tests to determine a brain injury’s severity. These tests include:
Cerebral hypoxia is a medical emergency. You should call 911. Emergency responders and healthcare providers will take measures to quickly restore oxygen flow to the brain. If a heart attack or stroke led to oxygen loss, they will treat the condition.
If someone near you stops breathing, you can perform CPR (if their heart has stopped) and give rescue breaths. These efforts can restore blood flow and oxygen until a medical team arrives. Your actions may prevent serious brain injury.
It’s important to manage conditions like high blood pressure. Conditions that can cause a heart attack or stroke increase the risk of cerebral hypoxia.
You can also take safety measures to lower the risk of accidents that cause cerebral hypoxia. You and your family can:
A person with mild cerebral hypoxia may have few, if any, symptoms. They may recover without noticeable long-term effects.
The outlook for someone with cerebral hypoxia depends on:
Studies suggest that a person who comes out of a coma in less than four weeks has a better chance of recovering with little long-term damage.
Some people remain in a persistent vegetative state. This means they appear to be awake, but they can’t consciously respond to commands or communicate. The odds of recovery aren’t good if this condition lasts for more than three months.
You should call 911 if someone experiences:
If a loved one has cerebral hypoxia, you may want to ask a healthcare provider:
A note from Cleveland Clinic
Cerebral hypoxia requires immediate medical care. The longer a person goes without oxygen, the greater the risk of severe brain damage and brain death. Recovery from cerebral hypoxia often involves physical, occupational and speech therapies. Your healthcare provider can connect you with resources that can aid recovery.
Last reviewed by a Cleveland Clinic medical professional on 05/04/2021.