Definition Of Death Debated
Modern technology has blurred the definition of death, say medical ethicists.
"Neither the controversy nor the process (of diagnosing death) has changed substantially over the past 250 years," say Professor David J. Powner, Professor Ake Grenvik, and Dr. Bruce M. Ackerman. The three authors are medical professors at the University of Pittsburgh School of Medicine.
Before the discovery that the heart could be resuscitated, the authors write, people assumed that death came when the heart ceased to function. With resuscitation came the uneasy feeling that what appeared to be death might merely be coma, overdose, or shock. Such fears in the 19th century led to the recently deceased being watched for a period of days, and to crypts and coffins being made 'escapable'.
This century saw the rise of defibrillators, artificial respirators, and organ transplants. It became clear, say the authors, that only the brain was immune to resuscitation or replacement, leading "to a focus on the brain as the 'vital' structure separating life and death."
In 1965, the term "brain-dead" was coined when a renal transplant took place using organs donated from a patient with no recorded brain function. But, even the lack of brain waves as a marker of death has problems, say the authors. "There appeared patient cases or... technological limitations that cast doubt upon its accuracy as the absolute test of absent brain function," they write.
A 1981 President's Commission found that cessation of blood flow, lack of respiration, and loss of full brain function defines death. But because the body can be kept alive by only one primitive part of the brain -- the brainstem -- confusion remains. "The irreversible loss of 'higher brain functions'... might allow death to be declared even if brainstem neurological function persists," explain the authors. Cases like anencephalic babies -- born without the more evolved parts of the brain but with beating hearts and functioning organs -- beg the question as to what constitutes life, as well as what defines death.
The study says that one line of thought holds that "all other bodily functions become secondary to vital 'personhood'." When higher brain function is lost, say the authors, so is personality, memory, and consciousness itself. Therefore, anencephalic infants, say the researchers "could be regarded as possible heart-beating organ donors" -- and nothing more.
Study authors say the same could hold true for adults. "If higher functions that were previously present are irreversibly lost," the authors explain, "proponents [of the higher function brain-dead definition] argue that such patients are dead" -- and may become organ donors.
If loss of "personhood," or cognition, constitutes loss of life, study authors say hard questions would have to be answered. What is cognition? Is it found in specific brain areas? Do we have the tools to accurately determine it no longer exists? How long is long enough to give up hope that it will never return?
Officials and experts from the American Academy of Neurology, the Child Neurology Society, and other medical groups have established the Multi-Society Task Force on Persistent Vegetative State to address such issues. They have issued certain rules to help physicians decide when brain death has occurred. Uncertainty seems to have the last word, however -- the guidelines end with this statement: "Exceptions to these rules are acknowledged."
SOURCE: The Lancet (1996;348:1219-1223)
NEW YORK (Reuters) --
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