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Brain Death


Defining Death

Under Australian law there are two definitions for death: cardiac death and brain death. Cardiac death occurs when a person is not breathing and their heart stops and cannot be restarted. As a consequence of this the brain will then stop functioning as it is being starved of oxygen. Brain Death occurs as a result of the same things except they occur in a different order. The brain sustains a severe injury, is starved of oxygen and stops functioning. As the brain stops functioning vital centres become affected, the person stops breathing on their own and eventually the heart stops.

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How does a person become brain dead?

Brain injuries from direct head trauma, bleeding in and around the brain from blood vessels, or acute lack of oxygen as a result of a cardiac or respiratory arrest may lead to an increase in the pressure inside the skull which causes a coma. When the brain is injured it swells just as any part of the body does. The skull contains the brain, its blood supply and the cerebral spinal fluid. The pressure inside the skull is held in a delicate balance by the normal volumes of these three components. If there is an increase in the volume of one component that is not offset by a decrease in the other components the pressure inside the skull will rise. This increase in pressure could lead to a decrease to the oxygen supply and b rain cells begin to die after minutes when starved of oxygen, resulting in permanent brain damage. If the brain swelling increases it can push the brain downwards onto the brain stem, which is where the spinal cord and brain join at the back of the neck. When this happens, vital brain stem functions, which are necessary for life, stop. The brain stem controls our breathing, our heart rate, and our blood pressure and body temperature. Brain cells cannot regrow or be replaced. Unlike coma, brain death is irreversible.

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What happens in Intensive Care?

The aim of Intensive Care treatment for someone in a coma is to control and then decrease the brain swelling to prevent damage from a lack of oxygen supply. The patient will be closely monitored using a bedside monitor, an arterial line and oxygen saturation monitor. The patient will be fully ventilated, receive intravenous fluids and drugs, have an indwelling urinary catheter, and may be taken to theatre for temporary removal of a piece of skull to relieve the pressure caused by the swelling and insertion of a drain into the brain to monitor and relieve the pressure. Sometimes, despite this treatment the brain swelling increases and the person will progress to brain death. The medical and nursing staff in Intensive Care will be constantly monitoring the patient for changes in their condition. There are a number of physical changes in pupil reaction, heart rate, blood pressure and body temperature when the brain dies. These changes together with the loss of other natural responses such as breathing, coughing and blinking cause the medical staff to suspect that brain death has occurred. Tests would then be done to find out whether or not the brain is working.

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How is brain death diagnosed?

There is a checklist of things that must be covered before brain death tests can begin. The checklist rules out whether or not there are other causes of the coma. Two appropriately qualified senior doctors 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 involuntary reflexes are working. They will be looking to see if the person has any: response to pain; response to light by the pupil of each eye; blinking response when each eye is touched; eye movement or response to ice cold water when it is put into the ear canal,; cough or gag (swallowing) reaction when the back of the throat is touched; breathing when the person is disconnected from the ventilator . For a person to be declared brain dead they must not show any response to each and every one of these tests.

There are times when some patients may not be able to have all of these tests performed. This is often due to the nature of the injuries that have been sustained. For example, a spinal injury, eye or facial injury will mean those nerves cannot be adequately tested. In this case, special x-rays are done to check if there is any blood flow to the brain. The patient’s time of death will be recorded as the time brain death was confirmed.

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Why does the patient still appear alive?

During this time the patient will be warm and pink and their chest will be moving. After brain death has been confirmed the patient will remain connected to the ventilator until the decision is made when to stop the ventilation. The patient’s heart will continue to beat as it has a natural pacemaker that works independently of the brain and will keep working at this time whilst it receives oxygen. If the ventilator is not stopped, because the brain has already died the patient will progress to kidney, liver and then cardiac failure over a period of hours to days.

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What happens when brain death is diagnosed?

After brain death has been confirmed the Intensive Care doctor will meet with the immediate family to confirm the result of the brain death testing and discuss the implications of this outcome. Patient care will not change until after that meeting has taken place. Options for a family at this time are to stop the ventilation and allow the heart to stop or if the patient wanted to be an organ donor – to keep the patient in Intensive Care connected to the ventilator receiving care for another 10 to 12 hours. Organ and tissue donation is discussed in a separate sheet. Please use the hyperlink on organ and tissue donation. NB the patient could still be a tissue donor after the heart stops.

If the family opts to stop the ventilation and/or declines organ and tissue donation, the medical and nursing staff will discuss and plan this process with the family. Every attempt will be made to individualise this process to suit each family, keeping in mind that the patient is now legally dead and their heart may stop due to cardiac failure prior to the ventilation being ceased. Intensive Care Units have the support of social workers, pastoral care workers and ministers of religion to assist the family during this time. Once the ventilator is switched off the heart will stop almost immediately.

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What are the implications of a Coronial investigation?

Every death that occurs in Intensive Care in NSW will be assessed for cause to come within the jurisdiction of the NSW Coroner’s legislation. A patient’s death will be referred to the Coroner in NSW as a matter of law, under the following circumstances:

  • If the event that lead to the patient’s death was sustained in a car accident or through other traumatic circumstances;
  • If the patient has had an anaesthetic within the previous 24 hours up to the time death was diagnosed;
  • If the patient is under a custodial order or under State care;
  • If the patient had an accident within a year and a day, which may have contributed to the cause of death;
  • If the patient has not been under the care of a medical practitioner within the past three months;
  • If the Intensive Care doctors are unable to complete the death certificate because of unknown factors leading to the death.

NB if the deceased person wishes to be an organ and tissue donor permission is sought from the Coroner and Forensic Pathologist as well as the next of kin for the retrieval to take place.

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  • Understanding Brian Death and Organ Donation: Living beyond Loss. Australian & New Zealand Organ and Tissue Donation Agencies.

Web pages:

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The information contained on this page is general in nature and therefore cannot reflect individual patient variation. In addition it reflects Australian intensive care practice which may differ from other countries. It is meant as a back up to specific information which will be discussed with you by the Doctors and Nurses caring for your loved one. ICCMU 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.

Brain Death Version 1 March 2005(Authors Kaye Rolls CNC ICCMU and Jane Treloggen SESAHS Organ and Tissue Donation Coordinator)

Published October 2005

Last Updated on Wednesday, 18 December 2013 23:49