Brain death factsheet


Death is when the functions of the body that keep you alive, like your brain and heart, permanently stop working.

There are two types of death in medicine.

  1. Circulatory death

Circulatory death is when a person's heart and breathing permanently stop. The person will not move, and their skin will be cold. This is the most common way people die.

  1. Brain death

Brain death is when the brain and brainstem stop working completely. 

How brain death happens

The brain needs a constant supply of oxygen-rich blood to keep the body running. 

The brain starts to swell when it experiences things like:

  • serious injury to the head
  • bleeding into the brain
  • infection
  • time without oxygen or blood flow.

The skull protects the brain and prevents swelling. If pressure builds up in the skull, it can compress the blood vessels that supply oxygen to the brain and stop blood from flowing.

As pressure builds up, the brain will start to swell downwards where there is an opening in the bone. 

The swelling can injure the brainstem and stop it from working. The brainstem is the part of the brain that connects to the spinal cord and controls all the important functions like breathing and heart rate.

Unlike other cells in the body, the brain cannot regrow itself after damage. When the brain and brainstem are damaged and stop working, they will not be able to start working again.

Brain death is not the same as brain damage, injury, or coma. It is a permanent condition where a person has died. 

Signs and Symptoms

Brain death looks different to circulatory death. A person may still look like they are alive because of the support machines that keep the heart and lungs functioning without the brain's help.

Signs of brain death include:

  • pupils in the eyes that do not change depending on the light
  • eyes that do not blink when the surface of the eye is touched
  • eyes that do not move when the head is moved
  • no gagging reflex when the back of the throat is touched
  • no breathing when the support machine is switched off
  • no brain activity can be seen on an electroencephalogram test.


Two different doctors will perform specific tests separately to make sure brain death is diagnosed correctly.

To diagnose brain death, they will need to confirm that: 

  • there is enough evidence to confirm a brain injury
  • the condition is not caused by sedative medicine
  • there is no other reversible cause of their brain condition.

Doctors perform different reflex tests to check the nerves in the brainstem. If there is no response, it means that the person has experienced brain death. 

If reflex tests can't be done, scans will be done to check for blood flow to the brain.


Every possible effort is made to save lives, but there is no treatment available for brain death. 

Before brain death can be confirmed, a machine known as a ventilator is used to pump oxygen into the lungs and prevent further damage. 

Ventilators can be confusing to see, as the chest rises and falls as it does during normal breathing. It is important to note that even if a child remains on the ventilator, they will not recover from brain death.

Once the ventilator is removed, the breathing and heartbeat will stop. 


Caring for a child after brain death

Once brain death is confirmed, your child will stay connected to the ventilator while appropriate members of the medical team speak to you about the next steps.

This includes decisions like:

  • whether or not to donate your child’s organs and tissues
  • any end-of-life wishes, like religious rites
  • when the ventilator will be removed and who will be there.

Your child will have the best care, dignity, and respect at the end of their life, no matter what decisions are made, how the brain death happened or who is there.

Last updated Tuesday 19th March 2024


This factsheet is provided for general information only. It does not constitute health advice and should not be used to diagnose or treat any health condition.

Please consult with your doctor or other health professional to make sure this information is right for you and/or your child.

The Sydney Children’s Hospitals Network does not accept responsibility for inaccuracies or omissions, the interpretation of the information, or for success or appropriateness of any treatment described in the factsheet.

© Sydney Children’s Hospitals Network 2024