What is brain death?
Brain death is when the brain has been so badly damaged that it completely and permanently stops functioning. This can happen after a severe head injury, bleeding in the brain from a stroke or a haemorrhage, an infection in the brain or a lack of oxygen to the brain.
Just like any other part of the body, when the brain is injured, it swells. Because the brain is encased in the skull, which is rigid, this swelling can result in an increase in pressure. The swelling and pressure might become so severe that blood flow to the brain is blocked, which causes further damage to the brain.
Brain cells are very sensitive to a lack of blood and oxygen. Without these, the brain cells die. When this happens, the brain stops performing vital functions such as the controlling breathing, controlling the heart rate, keeping blood pressure up and keeping body temperature up. These are all necessary for life.
Since brain cells cannot grow or recover, brain death is irreversible.
Under Australian law, brain death is one of two situations in which a person can be certified dead. The other is circulatory death, which is when a person’s heart stops functioning.
What happens in Intensive Care?
When someone with a brain injury is admitted to an Intensive Care Unit (ICU), they will be given treatment aimed at controlling and decreasing the brain swelling.
- be ventilated, that is given breathing assistance (see Breathing support)
- receive intravenous fluids and drugs
- have an indwelling urinary catheter put in (see Equipment)
- have a piece of skull removed, and a drain inserted, to relieve the pressure caused by the swelling
- be closely monitored for any changes in their condition.
Sometimes, despite treatment, the swelling continues and the brain begins to die. When this happens, physical signs show, with changes to the way the pupils react to light, to the heart rate, to blood pressure and to body temperature. These changes, together with the loss of other natural processes such as breathing and blinking, show the medical staff that the brain has died.
To confirm brain death, a number of clinical tests are done.
How is brain death confirmed?
Before brain death can be confirmed, the following is required.
- There must be sufficient evidence of severe brain injury.
- It must be certain that the person’s condition is not due to sedative drugs.
- It must be clear that there is no other reversible cause of the person’s condition.
Two senior doctors must perform separate tests at the bedside to determine whether the brain is working or not. These doctors check to see if the cranial nerves that pass through the brain stem and control all vital reflexes are working.
They also check to see if the person:
- has any response to pain
- has any response when a light is shone in the pupil of each eye
- blinks or moves when each eye is touched
- responds to ice cold water put into the ear canal
- has a cough or gag (swallowing) reaction when the back of the throat is touched
- can breathe when disconnected from the ventilator.
For a person to be certified brain dead, they must show no response to every one of these tests.
In some cases, not all of these tests can be done, such as when there are extensive facial injuries. In such cases, radiological imaging is done to check if there is any blood flow to the brain.
The patient’s time of death will be recorded as the time that brain death was confirmed.
How can someone who is brain dead still seem to be alive?
During the process of brain death, someone’s skin can still feel warm and look pink, and their chest will be moving. This is because they are connected to a ventilator, and the heart can continue to beat as long as it receives oxygen. Once the brain has died though, the kidneys, liver and eventually the heart will fail over a period of hours to days.
What happens after brain death is confirmed?
Once someone has been confirmed as brain dead, and before anything else is done, the ICU doctor will meet with their immediate family to explain the situation and decide when the ventilator should be switched off and the heart allowed to stop.
If the person who has died is able to donate their organs and tissue, the doctor will discuss with the family the possibility of donation. If the family agrees to donation, the patient will be kept in the ICU connected to the ventilator receiving care for another 12 - 24 hours. If the family decides to stop the ventilator, and/or decides not to donate their loved one’s organs and tissue, the ICU staff will help guide them through this process.
Every attempt will be made to cater to the wishes of each individual family, keeping in mind that once someone is brain dead, their heart may stop even before the ventilator is turned off.
Social workers, pastoral care workers and ministers of religion are available to help the family during this difficult time.
When is there a coronial investigation?
Every death that happens in an Intensive Care Unit in NSW is assessed to determine if a coronial investigation is required. A death must be referred to the NSW Coroner as a matter of law if:
- the person died a violent and unnatural death
- the person died a sudden death and the cause is unknown
- the person had not been under the care of a doctor within the past six months
- the person died unexpectedly after having a health-related procedure (such as an operation)
- the person was under a custodial order or under State care at the time of death
- the doctor was unable to complete the death certificate because of unknown factors leading to the death.
Note: if the person who died wished to be an organ and tissue donor or the next of kin has agreed to donation, permission is sought from the Coroner and the forensic pathologist. If the next of kin do not wish the person who has died to become an organ and tissue donor, the Coroner and the forensic pathologist can not override their wishes.
The information on this page is general in nature and cannot reflect individual patient variation. It reflects Australian intensive care practice, which may differ from that in other countries. It is intended as a supplement to the more specific information provided by the doctors and nurses caring for your loved one. ICNSW attests to the accuracy of the information contained here but takes no responsibility for how it may apply to an individual patient. Please refer to the full disclaimer.