Redefining Death - A New Criterion For Death

Advances in medical science have complicated the definition of death. Life-saving measures such as cardiopulmonary resuscitation (CPR) or defibrillation (electrical shock) can restart cardiac activity. The development of the mechanical respirator in the 1950s also prompted a change in the concept of death. An unconscious patient, unable to breathe without assistance, could be kept alive with a respirator and, based on the heart-and-lung criterion, the patient could not be declared dead.

Further complicating the issue was the transplantation of the first human heart. Experimental organ transplantation had been performed since the early 1900s. In the 1960s, transplantation of organs such as kidneys became routine practice. Kidneys could be harvested from a patient whose heart had stopped and who therefore could be declared legally dead. A successful heart transplant, on the other hand, required a beating heart from a "dead" donor. On December 3, 1967, South African surgeon Christiaan Barnard transplanted a heart from a fatally injured accident victim into a man named Louis Washkansky.

Physicians who had been debating how best to handle patients whose life functions were supported mechanically now faced a new dilemma. With the first successful heart transplant, such patients now became potential heart donors, and it became necessary to ensure that a patient was truly dead before the heart was actually removed. Thus physicians proposed a new criterion for death—irreversible cessation of brain activity, or what many termed "brain death."

The Harvard Criteria

In 1968 the Ad Hoc Committee of the Harvard Medical School to Examine the Definition of Brain Death was organized. The goal of the Harvard Brain Death Committee, as they were also known, was to redefine death. On August 5, 1968, the committee published its report, "A Definition of Irreversible Coma," in Journal of the American Medical Association. This landmark report, known as the Harvard Criteria, listed the following guidelines for identifying irreversible coma:

• Unreceptivity and unresponsivity—the patient is completely unaware of externally applied stimuli and inner need. He/she does not respond even to intensely painful stimuli.
• No movements or breathing—the patient shows no sign of spontaneous movements and spontaneous respiration and does not respond to pain, touch, sound, or light.
• No reflexes—the pupils of the eyes are fixed and dilated. The patient shows no eye movements even when the ear is flushed with ice water or the head is turned. He/she does not react to harmful stimuli and exhibits no tendon reflexes.
• Flat electroencephalogram (EEG)—this shows lack of electrical activity in the cerebral cortex.

The Harvard Criteria could not be used unless reversible causes of brain dysfunction, such as drug intoxication and hypothermia (abnormally low body temperature—below 32.2 degrees centigrade or 89.96 degrees Fahrenheit core temperature), had been ruled out. The committee further recommended that the four tests be repeated twenty-four hours after the initial test.

The Harvard committee stated, "Our primary purpose is to define irreversible coma as a new criterion for death." Despite this, the committee in effect reinforced brain death—a lack of all neurological activity in the brain and brain stem—as the legal criterion for the death of a patient. A patient who met all four guidelines could be declared dead, and his or her respirator could be withdrawn. The committee added, however, "We are concerned here only with those comatose individuals who have no discernible central nervous system activity." Brain death differs somewhat from irreversible coma; patients in deep coma may show brain activity on an EEG, even though they may not be able to breathe on their own. People in a persistent vegetative state are also in an irreversible coma; however, they show more brain activity on an EEG than patients in deep coma and are able to breathe without the help of a respirator. Such patients were not considered dead by the committee's definition because they still had brain activity.

Criticisms of the Harvard Criteria

In 1981 President Ronald Reagan assigned a national commission to study the task of defining death. The President's Commission for the Study of Ethical Problems in Medicine and Biomedical and Behavioral Research reported that "the 'Harvard Criteria' have been found to be quite reliable. Indeed, no case has yet been found that met these criteria and regained any brain functions despite continuation of respirator support."

The President's Commission, however, noted the following deficiencies in the Harvard Criteria:

• The phrase "irreversible coma" is misleading. Coma is a condition of a living person. A person lacking in brain functions is dead and, therefore, beyond the condition called coma.
• The Harvard Brain Death Committee failed to realize that spinal cord reflexes can continue or resume activity even after the brain stops functioning.
• "Unreceptivity" cannot be tested in an unresponsive person who has lost consciousness.
• The committee had not been "sufficiently explicit and precise" in expressing the need for adequate testing of brain stem reflexes, especially apnea (absence of the impulse to breathe, leading to an inability to breathe spontaneously). Adequate testing to eliminate drug and metabolic intoxication as possible causes of the coma had also not been spelled out explicitly. Metabolic intoxication refers to the accumulation of toxins (poisons) in the blood resulting from kidney or liver failure. Though these toxins can severely impair brain functioning and cause coma, the condition is potentially reversible.
• Although all persons who satisfy the Harvard Criteria are dead (with irreversible cessation of whole-brain functions), many dead individuals cannot maintain circulation long enough for re-testing after a twenty-four-hour interval.