Right: The emergency room of a city hospital, where many accident victims are saved. Those who are not are frequently diagnosed as brain dead, while their bodies are kept "alive" by life-support machines. The families of these people are often approached for permission to use their relative's organs to save the lives of strangers.
Background information
Brain death and cardiac death(The following explanation of brain death and cardiac death is that supplied by Sydney Children's Hospital. It is intended to make sense to people without a medical background and, though a simplification of procedures applied, is in accord with Australian and New Zealand Intensive Care Society Statement on Death and Organ Donation.
The full text of the Sydney Children's Hospital explanatory statement can be found at http://www.sch.edu.au/health/factsheets/joint/?brain_death_and_organ_donation.htm)
Most people understand that death occurs when a person's heart and breathing stop. This is called cardiac death and is how most people die. When someone has died of cardiac death, they do not breathe or move, they do not have a heart beat and their skin colour changes since blood is no longer circulating around the body. However, no one actually dies until the brain dies. The brain dies when blood stops being pumped to it. Other organs such as the heart and kidneys can stop working completely and in some circumstances are able to be revived - but not the brain. This is why people who have had a heart attack where their heart has stopped beating can be resuscitated - the heart may have stopped beating for a few minutes but because the brain hasn't died, the person may still be able to recover.
Death also occurs when the brain and brainstem stopped working completely - this is called brain death. The kinds of injuries which may cause the brain to die include accidents where there is trauma to the head, bleeding into the brain, infections or a long period of time without oxygen. As part of the treatment for these conditions, the person will be connected to a machine called a ventilator, which artificially pushes oxygen into the lungs, causing the chest to rise and fall as if the person is breathing. Even though the heart may still be beating and all other organs may still be working, brain death is death. The person cannot ever recover because the brain, once dead, can never be repaired.
A person who has died as a result of brain death will look very different to a person who has died from cardiac death. Because they are attached to the ventilator and receiving oxygen, the heart will continue to beat and the skin will be pink and warm. This is why it can be difficult to understand and accept that someone who is pink and warm and appears to be asleep is actually dead.
What causes the brain to die?
Like all of our organs, the brain needs a constant supply of oxygenated blood to keep working. When any part of the body is injured it swells. The brain is no different. An injured finger or ankle can keep expanding because there is nothing to restrict it. The brain however, is contained within the rigid skull that limits how much it can expand. As the brain continues to swell, pressure builds up within the skull.
It is this increased pressure within the skull that causes so many damaging and permanent effects:
The blood and oxygen stop flowing to the brain because the blood vessels get squashed.
Without the oxygen, brain cells die and cannot re-grow or recover. This may cause further swelling.
The swelling causes the brain to push down on the brainstem, which is where the spinal cord and the brain join at the back of the neck, and stops the functions of the brain stem.
The brain stem controls breathing, heart rate, blood pressure and body temperature.
Rates of organ donation in Australia
Australia has one of the best records in transplantation outcomes in the world; however, more than 1,800 Australians are waiting for a transplant at any given time owing to a shortage of donors.
Australia's organ donation rate has hovered around 200 donors per annum for many years. Although surveys indicate more than 90 per cent of Australians support the idea of organ and tissue donation, the country continues to have one of the lowest rates of donation in the Western world.
In 2000, the Australian organ donation rate was 10 per million population. There was considerable variation in the rates for the States and Territories. South Australia had the highest rate, 20 donors per million population. In other States for which reliable rates could be calculated, rates of donation ranged from 9 per million population for New South Wales, to 12 for Western Australia.
Compared with other countries for which information is available, Australia's donation rate of 10.2 per million population - the number of people who die and become donors out of the (live) population - is low. When organ donation rates are compared per 1,000 deaths, the difference between the donation rate for Australia and some other countries is reduced. In 2000, Australia's donation rate of 1.5 per 1,000 deaths was comparable with estimated rates for New Zealand and for several European countries, including the United Kingdom and Ireland, the Netherlands and Germany.
In 2000, Spain had the highest donation rate, whether calculated per million population (33.9) or per 1,000 deaths (3.9). Over the 1990s Spain had a high and increasing rate of donors per million population. The rate rose rapidly from 14.3 per million population in 1989 to more than 20 in 1991, and had exceeded 30 by 1998. This has been attributed to procedures introduced by a national transplant organisation set up in 1989, which included having donation coordinators in hospitals, training medical staff in requesting donation, and closely monitoring potential and actual donation.