Artificial means can maintain breathing and keep the heart beating for a while, but once brain death occurs, nothing can keep the other organs functioning indefinitely.
Doctors must use specific criteria to diagnose brain death.
No treatment can help a person who is brain dead.
A diagnosis of brain death is equivalent to a person's death.
Brain death means that the brain stops functioning. People do not respond to any stimuli. No treatment can help, and once the diagnosis is confirmed, a person is considered legally dead.
In the past, the idea of brain death was irrelevant because when the brain died, so did the rest of the body. That is, the person stopped breathing, and the heart stopped beating. However now, artificial means (such as ventilators and drugs) can temporarily maintain breathing and the heart’s beating even when all brain activity stops. But eventually, even with help from artificial means, all the body's organs stop working. Nothing can keep the heart beating indefinitely once brain death occurs.
There are specific criteria for diagnosing brain death. They include
Checking for and correcting all treatable problems that could alter brain function and thus result in a misdiagnosis of brain death (such as very low body temperature, very low blood pressure, or very low blood levels of certain substances such as sugar and sodium or an overdose of a sedative)
Identifying and treating any condition that could cause coma and irreversible loss of all brain function
Testing the person's reflexes (such as the gag reflex, triggered by touching the back of the throat) and observing no response (the person does not grimace, move, or otherwise react)
Testing the eyes and observing no reaction to light
Testing breathing by taking the person off the ventilator and observing that the person makes no attempt to breathe
Doctors should maintain communication with the family or attempt to notify the person's next of kin or a close friend of their findings as soon as the diagnosis and evaluation of brain death begins.
Doctors typically recheck the criteria 6 to 24 hours later to confirm the person's lack of response.
All of the following must be done:
In adults, brain death can be confirmed after a second check is done 6 to 24 hours later. For children, some states advise doctors to do two separate examinations, separated by at least 48 hours.
Occasionally, doctors use certain diagnostic tests to help confirm brain death. The tests are typically done only to make organ donation possible—for example, after catastrophic head injuries (as may occur in car crashes). These tests can be done instead of testing a person's breathing, which requires several tests. Testing whether a person can breathe is undesirable because each test deprives organs of oxygen, risking further damage to organs that are intended for donation. The tests include
No one who meets the criteria for brain death recovers. Thus, once brain death is confirmed, the person can be considered dead.
After brain death is confirmed, all life support is stopped. Family members may wish to be with the person at this time. They need to be told that one or more limbs may move when breathing assistance is ended or that the person may even sit up (sometimes called the Lazarus sign). These movements result from spinal reflex muscle contractions and do not mean the person is not really brain dead.