Consciousness vs. physiology: When is death really death?
Researchers reconsider the brain’s role in preserving life
Even as this country struggles with a shortage of organs from donors, some ethicists are beginning to question the morality of harvesting organs from the group that serves as their primary source — patients who are brain dead but have functioning hearts, lungs, and circulatory systems.
Since 1981, the primary criterion for declaring a patient dead has been a clinical diagnosis of "whole-brain death" — this determination being based on the theory that the brain is the central integrator of the body’s systems and, once the brain has irreversibly ceased to function, the organism as a whole will cease to function.1
However, recent neurological research is questioning whether the brain is indeed the central integrator of the body’s functions and whether, when a person’s brain is gone, they are as well.
"Whole brain-dead individuals have functioning circulatory systems which distribute oxygenated blood to the tissues and organs," argues Michael Potts, PhD, head of the philosophy and religion department at Methodist College in Fayetteville, NC. "Their respiratory systems also continue to function since the exchange of oxygen and carbon dioxide continues in the lungs and throughout the body, with the ventilator providing oxygenated air."
While it’s true that without the use of a ventilator or other technology, those functions would cease, that also is true of many people who are clearly alive and conscious and depend on such technologies to continue to live, he argues.
"Many people who are clearly alive and conscious depend on technologies ranging from cardiac pacemakers to ventilators in order to continue to live," he notes.
In 2001, pediatric neurologist Alan Shewmon, MD, published a report describing the case of a brain-dead child who survived for 14 years after the diagnosis of brain death.2
Although this person no longer has a brain, the body — with the assistance of mechanical ventilation and intravenous nutrition and hydration — has continued to grow, maintain metabolic functions, heal from infections and illnesses, etc.
Living without a brain
There have been numerous other reports of brain-dead pregnant women who have given birth to healthy babies, Potts adds. "It is clear that whole brain-dead individuals are functioning at the level of an organism as a whole, which falsifies the main justification for the whole-brain criterion," he says.
Some ethicists feel, however, that to say a person is living because their body is functioning is a stretch.
"My view is that we are not human organisms — we are conscious beings whose existence is supported by the continued functioning of relevant areas of the brain," states Jeff McMahan, PhD, chair of the department of philosophy at the University of Illinois-Urbana, and the author of the book, The Ethics of Killing: Problems at the Margins of Life (Oxford University Press, 2002). "My view is that I am not one and the same thing as my body. What I am is a consciousness — my technical term for this is an embodied mind.’"
While it may be true that a person’s body — the human organism — may continue to live after the brain ceases to function, it is difficult to say that the person also continues, he explains. Brain-dead people are no longer capable of consciousness or awareness, and once the brain is completely destroyed, the damage is irreversible. It is this determination that first led clinicians to embrace the concept of brain death over previous standards of determining death that relied primarily on cardiopulmonary functioning.
"In the late 1960s, we shifted from the older cardiopulmonary criteria of death," he explains. "The big moment came in 1968 when the Harvard Brain Death Committee presented arguments focusing on the irreversible loss of the capacity for consciousness. Basically, they argued that at the point the whole brain dies, we are sure the coma is irreversible."
However, as knowledge of the brain’s function has grown, it was discovered that patients who have brainstem, or "lower brain," function but have lost the functions of the cortex or "higher brain" are also not capable of consciousness or of regaining consciousness.
Then some advocated for new criteria — "higher-brain" or "neocortical" brain death to become the new standard — since consciousness was not possible for these patients as well.
"Those people say once the cerebral cortex or cerebral hemispheres are gone, the person is dead because there is no longer any possibility of consciousness," McMahan says. "The problem is that’s the state that people in persistent vegetative states are in — they can be lying in a hospital bed without a respirator, spontaneously breathing, heart beating without assistance. It is very difficult to argue that a biologically dead organism is lying on a hospital bed, breathing on its own."
At that point, the 1981 President’s Commission for the Study of Ethical Problems in Medicine and Biomedical and Behaviorial Research decided to keep the whole-brain standard based on the brain’s role as the integrator of the main functions of the human organism.
Most states currently adhere to the Uniform Determination of Death Act, which holds that an individual can be declared dead either due to irretrievable loss of heartbeat and respiration or due to whole-brain death.
What defines death?
Now that that role has come into question, McMahan agrees that use of the whole-brain death standard is problematic. Deciding who is dead and when is largely based on our beliefs as a society about the value of human life, what constitutes life vs. prolonged death and how we should deal with both.
"When I cease to exist is an individual choice," believes McMahan. "Since I think I am not the same thing as my organism is, I can believe that the higher brain criteria is the right criteria for my death, that when the cerebral hemispheres die, I have ceased to exist, but that is perfectly consistent with my body remaining alive."
Potts believes, however, that it is possible to have an objective, universal determination of death — but one that does not focus primarily on brain function. In his view, a person continues to exist as long as their body continues to function as a whole.
"The organism is dead when it no longer functions as a whole," he explains. "This is true of plants, bugs, sharks, cats, and humans. However, the criteria that are sufficient to show that an organism is no longer a whole will depend on the type of organism. Obviously, the criteria for death of a tree with differ from the criteria for the death of a cat."
The proper criteria of death for humans should be understood in terms of the destruction of key bodily systems necessary for the integrated unified functioning of the organism, he adds. "The nervous system is one of these key systems, but so are the circulatory and respiratory systems. We know that bodily cells, tissues, and organs will not survive for long without the circulation of oxygenated blood. The proper criteria for the death of the human organism then should refer to these key systems: Death should only be declared after the destruction [not just the loss of function] of the circulatory, respiratory, and nervous systems. How long after the cessation of function such destruction occurs is a matter for medical science to determine."
But such a view can have pernicious effects in the real world, McMahan argues. People who will never regain consciousness can continue to live in a motionless, twilight, unaware state though their organs may be able to help others live productive lives, and their families may be able to grieve and accept the loss of a person who will not return.
Many parents of anecephalic babies wish to donate their child’s organs before allowing the child to die, but this is not allowed because these children have brainstem function.
"Anecephalic babies are born without a higher brain — so there is never any consciousness," McMahan notes. "They are empty, unoccupied organisms because there is no consciousness at all."
But because these organisms are considered alive, their organs cannot be harvested. The parents are allowed to take their children off life support to allow nature to take its course, but the organs will never be used.
Another option would be to admit that these organisms are alive in some way, but that they are not people capable of living in the way that we normally understand it, he argues. But Potts contends that such thinking goes against the core values of respect for human life and the physician-patient relationship.
"I think the issues of withdrawing life support and/or organ donation need to be separate," he says. "Withdrawing life support from a dying patient is meant to allow nature to take its course — the patient does not receive extraordinary burdensome treatment. Just as it is not morally obligatory to give antibiotics to a terminally ill cancer patient, though it is morally permissible to do so, it is not morally required that a dying patient remain on a ventilator. The focus on withdrawing care is on the good of the individual patient, to allow that person to die as comfortably as possible."
The main problem with organ donation from beating-heart, brain-dead donors, Potts argues, is that if such donors are alive —there is good reason to believe they are — removing an unpaired vital organ (heart, liver) or both paired vital organs (both lungs or both kidneys) kills the patient.
"Instead of unnecessary treatment being withdrawn, healthy organs are removed, not for the benefit of the donor, but for the benefit of another person," he says. "Actively killing the brain dead promotes treating people as only a means to an end and not as ends in themselves. It weakens the barrier against viewing other, less disabled, lives as not being worthy to live, either. This is a dangerous path to follow."
Sources
• Jeff McMahan, PhD, Department of Philosophy, University of Illinois, 105 Gregory Hall, 810 S. Wright St., Urbana, IL 61801.
• Michael Potts, PhD, Philosophy and Religion Department, Methodist College, 5400 Ramsey St., Fayetteville, NC 28311-1420.
References
1. Guidelines for the determination of death. Report of the medical consultants on the diagnosis of death to the President’s Commission for the Study of Ethical Problems in Medicine and Biomedical and Behavioral Research. JAMA 1981; 246:2,184-2,186.
2. Shewmon AD. The brain and somatic integration: Insights into the standard biological rationale for equating brain death with death. J Med Philos 2001; 26:457-458.
Further reading
• Potts M. A requiem for whole-brain death: A response to D. Alan Shewmon’s "The brain and somatic integration." J Med Philos 2001; 26:479-491.
• Halevy A. Beyond brain death? J Med Philos 2001; 26: 493-501.
• Karakatsanis KG, Tsanakas JN. A critique on the concept of brain death. Issues Law and Medicine 2002; 18:127-141.
Even as this country struggles with a shortage of organs from donors, some ethicists are beginning to question the morality of harvesting organs from the group that serves as their primary source patients who are brain dead but have functioning hearts, lungs, and circulatory systems.
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