Patient education: Hypoxic brain injury (The Basics)

What is hypoxic brain injury? — 

This is damage that happens when the brain does not get enough oxygen. It is also sometimes called "anoxic brain injury."

The brain needs oxygen to work. Without it, brain cells start to die. If a person's brain goes without oxygen for too long, it can cause permanent brain damage or death.

What causes hypoxic brain injury? — 

Different things can cause the brain to not get enough oxygen. This can happen if blood can't get to the brain, or if there is not enough oxygen in the blood. Some examples include:

●Drug overdose

●Carbon monoxide poisoning

●Drowning or near-drowning

●Cardiac arrest, which is when the heart stops beating

What are the symptoms of hypoxic brain injury? — 

Very early symptoms of low oxygen in the blood can include:

●Headache

●Dizziness

●Confusion

●Tiredness

●Nausea

If a person's brain is not getting enough oxygen, they will pass out. This can lead to a coma, which is a deep state of unconsciousness. A person in a coma:

●Looks like they are asleep

●Cannot be woken up

●Cannot move on their own

●Does not respond to pain or react when spoken to, touched, or shaken

People in a coma sometimes twitch, move a hand or finger, or make faces or sounds. But this does not mean that they are aware, awake, or in control.

Is there a test for hypoxic brain injury? — 

If a person is unconscious, the doctors will try to figure out the cause if it's not clear. They will do an exam to see how the person responds to sound, touch, and pain. They will also check the person's reflexes, including how their eyes react to light.

There are also different tests that can look at brain function and blood flow. They include:

●Imaging tests – These create pictures of the brain and can show brain damage. Examples include CT scans and MRIs. Sometimes, doctors also do tests to look at the blood vessels. This is called "angiography."

●Electroencephalogram ("EEG") – This measures the electrical activity in the brain. It can measure brain waves. An EEG shows if a person is having seizures.

●Blood tests – Doctors usually order these if a person is in a coma and the cause is not clear. Blood tests can check for chemical imbalances and other problems.

What treatments might be needed? — 

If a person's brain has been injured by not getting enough oxygen, they need immediate treatment. The goal is to try to prevent further damage. Doctors and emergency workers might do different treatments, including:

●Hypothermia – This involves cooling the body to a few degrees below normal. After a person's heart has stopped beating, hypothermia can reduce the seriousness of brain injury.

●Medicine to stop seizures

●Treatments to give oxygen, control blood sugar levels, and prevent problems like infection or blood clots

When a person is in a coma, they will stay in the intensive care unit, or "ICU." There, doctors use machines to monitor their body functions. Some people need to be put on a machine that breathes for them, called a "ventilator." The medical staff will also give the person nutrition and medicines. When all of these things are needed to keep a person's body alive, it is called "life support."

Can a person recover from hypoxic brain injury? — 

It depends on what caused the injury and how long the brain was without oxygen. Unfortunately, many people with severe brain injury do not recover.

If a person is in a coma, this usually leads to 1 of the following within a few weeks:

●Death – "Brain death" is when there is no longer any brain activity. The brain cannot control the body's functions or respond to anything.

●"Persistent vegetative state" – This means that the person has brain activity suggesting that they go to sleep and wake up, but they otherwise seem like they are in a coma. If a person stays in this state for more than a few months, it will most likely be permanent.

●Recovery or partial recovery – Some people do wake up after being in a coma. But even if a person wakes up and begins to improve, they are likely to have long-term problems from their brain injury.

If you have a family member with a hypoxic brain injury, their doctors will talk to you about their situation. It is very hard to predict whether a person will recover and how much. Some things, like the person's test results and reflexes, can help doctors try to predict this. But it's not always clear, especially in the first days and weeks. Ask questions if you do not understand what the doctors tell you.

Having a loved one with a brain injury is scary and stressful, and it's important to have support.

If a person does recover, they will probably have at least some long-term problems. That's because when brain cells die, the damage is permanent. This affects people in different ways. Depending on the person's needs, different therapies and supports can help. Some people can get back some of their abilities and live a fulfilling life.

More on this topic

Patient education: Caring for someone after a hypoxic brain injury (The Basics)
Patient education: Moderate to severe traumatic brain injury (The Basics)
Patient education: Coma (The Basics)
Patient education: Breathing tubes and ventilators (The Basics)
Patient education: Advance directives (The Basics)
Patient education: Brain death (The Basics)