Staff writer Brain death: It’s a phrase we hear every day. In Japan, the public has been exposed to it to the point of numbness through nationwide campaigns for more organ donors. “Brain death is human death, and organ donation saves lives,” we are exhorted. In the United States, the world’s leading transplant center, organs are transplanted from 5,000 brain-dead patients a year. The issue of what constitutes brain death is yesterday’s controversy, isn’t it?
Arthur Caplan, a leading U.S. bioethicist at the University of Pennsylvania, thinks so. “It has been settled,” he says. “There is absolute consensus in the U.S.”
Yet it is increasingly apparent that there isn’t. Robert Truog, head of intensive care at Children’s Hospital in Boston, Mass., is just one of several medical professionals in the U.S. who argue that the neurological definition of death — so-called brain death — should be abandoned because it is theoretically incoherent.
“Very few patients we diagnose as brain-dead actually meet the criteria for brain death — the permanent cessation of functioning of the entire brain,” says the professor of anesthesiology and medical ethics at Harvard Medical School. “The criterion of whole-brain death is only an ‘approximation.’ “
Equally opposed is Alan Shewmon, professor of pediatric neurology at UCLA Medical Center in Los Angeles: “People in the future will laugh at us (for having adopted brain death as a criterion of death),” Shewmon says.
It is true that in the past few decades, brain death has become widely accepted in technologically advanced countries, although the consensus is split between the U.S. standard of “whole-brain death” and Britain’s “brain-stem death.”
The criteria for whole-brain death, proposed by an ad hoc committee of Harvard Medical School in 1968, have served two purposes — the withdrawal of life-sustaining treatment from those determined to be brain-dead and the procurement of organs for transplants from such patients.
Caplan maintains that the three decades since then have witnessed no major controversy, either medical or ethical, over brain death. “There has been no effort to change the Uniform Determination of Death Act (that says people are declared dead based either on cardiopulmonary or brain criteria),” he says.
But behind the consensus, some now argue, is the fact that brain-dead patients make ideal organ donors; since blood circulation is maintained below the neck, the organs remain fresh. Is it the irresistible utilitarian appeal of organ transplants that has made brain death so widely accepted?
Interpreting residual activity
In the brain-dead, all brain functions are supposed to be permanently lost. However, Truog says, many brain-dead patients continue to show posterior pituitary function and to secrete antidiuretic hormone.
“This is very definitely a brain function,” Truog says. In addition, tests for the diagnosis of brain death require the patient not to be hypothermic, because that can depress brain function and cause the body to falsely exhibit symptoms similar to those of brain death.
“The requirement is that the body is not to be hypothermic, yet (regulation of) body temperature is actually a brain function. If you are not cold, you still have some brain function,” Truog explains. “It is a kind of Catch-22. Hypothermic patients cannot be diagnosed as brain-dead, but the absence of hypothermia itself is the evidence of brain function.”
Besides, many patients who fulfill the tests for brain death continue to show electrical activity on their electroencephalograms, he said. “We don’t know whether this represents function, but in some cases the kind of activity that’s seen on the EEG looks very much like the kind of activity we see in dreamlike states. It is an open question as to whether these patients may have brain function.”
Dead or just unconscious?
Proponents of brain death claim it constitutes human death because, they say, it signals loss of function in “the organism as a whole.”
The expectation is that if somebody meets brain-death criteria, he or she will experience cardiac arrest within a very short time. That was in fact the case in the 1970s and ’80s. “But it is no longer factually true,” Truog says. “Intensive-care techniques have improved over the last 20 years. Now we can keep brain-dead patients physiologically going for an almost indefinite period of time.”
In December 1998, UCLA’s Shewmon published a paper titled “Chronic Brain Death” in Neurology, the journal of the American Academy of Neurology.” The paper shocked medical professionals.
Shewmon reported that there had been 175 cases in the U.S. of patients physically surviving a week or more after being declared brain-dead, many of them children or pregnant women whose life support had been maintained either because parents insisted or to save a fetus. (Usually, in the U.S., once patients are determined to be brain-dead, life support is terminated.)
Of the 175, 44 survived for four weeks, 20 at least 2 months, seven at least 6 months, and four longer than one year. One survived for 15 years.
“If you dismiss these cases as presumptive misdiagnoses, it would imply that organ donors are also often misdiagnosed and that brain-death declarations are inherently unreliable,” says Shewmon, who insists that the procurement of organs from brain-dead people should be stopped because it constitutes killing.
Another key determinant of survival capacity was the cause of the injury leading to the brain-death declaration. Etiologies were divided into two categories: primary brain pathology (such as intracranial hemorrhage or a gunshot wound to the head); and diffuse or multisystem damage (such as cases of cardiac arrest in which cardiac resuscitation was successful but the brain suffered severe damage, or motor vehicle accidents).
“The latter impairs survival more,” Shewmon says.
From his research, Shewmon concludes:
1) “Brain death” does not necessarily lead to imminent cardiac arrest.
2) Survival duration is largely explainable by nonbrain factors.
3) The first few weeks are precarious. But those who make it through tend to stabilize, no longer requiring sophisticated technological support.
In his latest research, published under the title “Spinal shock and brain death” in the journal Spinal Cord in July 1999, he points out that the “somatic pathophysiology” of high-spinal-cord transection can be virtually identical to that of brain death, the only difference being that spinal-cord injury victims are conscious.
“One can take a typical textbook chapter on the intensive care of brain-dead organ donors and a typical chapter on the intensive care of high-spinal-cord injury victims and essentially transform the one into the other merely by switching the terms ‘brain death’ and ‘spinal cord injury,’ ” he says. However, he stresses that the purpose of this comparison is not to advance a claim that brain death is clinically indistinguishable from spinal-cord injury, which would be absurd.
“But it is to say that if high-spinal-cord injury victims are alive at the level of the ‘organism as a whole,’ then brain-dead patients must be too, and the only significant difference is whether they have consciousness,” Shewmon said.
Robert Veatch, professor of bioethics at the Kennedy Institute of Ethics at Georgetown University in Washington, D.C., has long argued that a higher-brain-oriented definition of death should replace the whole-brain and brain-stem definitions.
He believes that the critical brain functions identified by the Harvard committee — such things as an individual’s personality, conscious life, capacity for remembering, judging, reasoning, acting, enjoying and worrying, a person’s “uniqueness,” in short — are not randomly distributed throughout the brain, but require the cerebrum.
“(Brain-dead individuals) would be dead by higher-brain criteria, but not by whole-brain criteria,” Veatch says.
The American Medical Association’s committee has said that it is possible to determine irreversible loss of consciousness, he says. “If that’s true, we can diagnose higher-brain death.” Veatch strongly criticizes Britain’s brain-stem criteria for death, saying that lack of activity in the brain stem does not mean there are no signals going in and out of the cerebrum.
“Under the brain-stem criteria, you could have a conscious person who would be determined dead,” he said.
But can U.S. doctors really tell whether somebody has lost consciousness completely?
In a 1989 case, the New York State Supreme Court vacated an order allowing withdrawal of life-sustaining treatment from a patient named Carrie Coons when she unexpectedly regained consciousness. Having suffered a massive stroke several months earlier at the age of 86, doctors thought Coons had entered a persistent vegetative state and required a feeding tube for nutritional support. The court supported a request from her sister that the feeding tube be withdrawn, convinced by the medical experts that she had no chance of recovery. When she then unexpectedly awoke and expressed feelings of uncertainty about the decision, the court’s order was vacated and nutritional support was reinstituted.
Asked how he could be sure that doctors can distinguish between patients who have completely lost consciousness and those who have merely a very low level of consciousness, Veatch said he leaves that up to the American Neurological Association.
“I’m a philosopher, not a neurologist,” he said. “(But) if neurologists say there’s no consciousness when they can’t prove there’s no consciousness, then they’re telling a lie to patients. That’s unethical.
“Physicians say, ‘We can very accurately guarantee that consciousness will never return.’ If they claim they know there is irreversible loss of consciousness for stopping ventilators, then they also should admit they can know there is no consciousness for purposes of higher-brain death. It’s the same diagnosis in both cases,” Veatch says.
Gail Van Norman, former assistant professor of anesthesiology at the University of Washington in Seattle, Wash., says, “If you ask neurologists, they will tell you with a great deal of confidence that they can make (that) determination. Yet when we study these things, we’re usually surprised how much less certainty there is.”
An arbitrary line
Van Norman says many doctors now think that what brain death represents is “the point of no return,” not the point of death. “That’s begun to bother us recently,” she said. “We have begun to say ‘Look, calling this death is not really honest. It’s probably not death, but the point of no return.’ ”
Colin McDonald, a neurologist at Massachusetts General Hospital in Boston, says brain death may seem like an arbitrary line drawn between life and death, but it is both practical and useful.
“A family needs something other than science to know when their loved one has no hope of recovery. Once the family hear that (term ‘brain death’), they can be better informed to advocate for the patient. It is our strict responsibility to help patients and families understand what is futile and what is appropriate. Right now, brain death is the best we have,” he said.
Van Norman does not agree. If the line really is a clear and practical one, she says, nobody would be disturbed — although she adds that the perception of brain death as “the point of no return,” rather than death per se, should not cause the public to fear incorrectly that patients might be treated as dead while they are still alive.
James Bernat, professor of neurology at Dartmouth-Hitchcock Medical Center in Levanon, N.H. and a longtime champion of the whole-brain-oriented definition of death, admits that brain death is a practical definition, even a kind of social construct.
“It is a little bit contradictory,” he says. Yet at the same time, “I believe it is a biological event that also has social acceptance.” The point, he says, is that the concept of whole-brain death has served well in the Uniform Determination of Death Act, which people have respected. “Even though there is still some controversy, public policies and laws (are) very coherent and (are) accepted by the public. It’s fairly settled from the point of view of public policy.
“In our country, the public accept organ transplantation (and) they have pretty strong confidence in physicians, so even though it is not a perfect concept, it is still sufficiently coherent to design a workable public policy,” Bernat said. He accepts many of the criticisms put forward by Truog and Shewmon, but takes issue with Veatch, saying that it is not possible to tell with 100 percent accuracy whether somebody has lost consciousness or not.
Bernat said he feels intuitively that brain death is defensible, but that he lacks adequate answers to the criticisms made by opponents, particularly Shewmon: “I need to try to think more carefully why (I feel the way I do), he said.”
The brain is an exceedingly complicated structure, he points out, and what even the best neurologists know is still relatively primitive: “We should be humble enough to recognize our limitations.”
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