Cerebral Hypoxia

What is cerebral hypoxia?

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.

How does lack of oxygen affect the brain?

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.

What causes lack of oxygen to the brain (cerebral hypoxia)?

Many things can affect oxygen flow to the brain, including:

• Choking, strangulation or suffocation.
• Drowning.
• Electrocution.
• Head injury, including traumatic brain injuries (TBI).
• Heart attack, arrhythmia and stroke.
• Substance use disorder, including drug overdose and inhalant misuse.
• Carbon monoxide poisoning or smoke inhalation.
• Seizure.
• Severe blood loss or hemorrhage.
• Surgical complications or anesthesia problems.

What are the signs of cerebral hypoxia?

A person experiencing cerebral hypoxia may:

• Appear disoriented and slur their words.
• Breathe rapidly or shallowly or stop breathing.
• Get a bluish or grayish tint to the skin and lips.
• Have dilated pupils, convulsions or seizures.
• Not respond when you say their name or ask them to do something like squeeze your hand.

What are the long-term effects of cerebral hypoxia?

People who recover from cerebral hypoxia may have lifelong problems, such as:

• Cognitive impairment or memory loss.
• Personality changes.
• Poor judgment or inability to focus.
• Problems with balance, coordination or walking.
• Spasticity (full body muscle contractions) or muscle spasms.
• Speech and swallowing difficulties (dysphagia).
• Vision problems.

What are the complications of cerebral hypoxia?

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.

How is cerebral hypoxia diagnosed?

A healthcare provider may order tests to determine a brain injury’s severity. These tests include:

• Angiography to check blood flow to the brain.
• CT scan or MRI to look for signs of stroke, bleeding in the brain, brain swelling or other trauma.
• Electroencephalogram (EEG) to measure electrical activity in the brain.
• Evoked potentials test to assess the brain’s response to sensations like touch.

How is cerebral hypoxia managed or treated?

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.

How can I prevent cerebral hypoxia?

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.

How can I lower my risk of cerebral hypoxia?

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:

• Buckle up with seatbelts.
• Install smoke detectors and carbon monoxide detectors in your home.
• Use life vests, swim at places that have lifeguards and supervise children around water, including bathtubs.
• Wear helmets during high-impact physical activities or while biking, skating or skiing.

What is the prognosis (outlook) for people who have cerebral hypoxia?

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:

• Length of time the brain goes without oxygen.
• Severity of brain damage.
• Age at the time of the incident (people younger than 25 may recover better).

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.

When should I call the doctor?

You should call 911 if someone experiences:

• Loss of consciousness or unresponsiveness.
• Seizures.
• Shallow or stopped breathing.
• Signs of heart attack or stroke.

What questions should I ask my doctor about cerebral hypoxia?

If a loved one has cerebral hypoxia, you may want to ask a healthcare provider:

• How severe is the brain injury?
• Would physical, occupational or speech therapy help?
• Can any medications help improve symptoms?
• What’s the long-term prognosis?
• Should I look out for signs of complications?

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.