The Metaphysics of Brain Death, Persistent Vegetative State, and Dementia

THE METAPHYSICS OF BRAIN DEATH, PERSISTENT VEGETATIVE STATE, AND DEMENTIA A.LIFE-SUPPORT TECHNOLOGY has advanced over the past half-century, a great number of thorny philosophical and moral problems have arisen regarding patients with serious neurologic damage, who in generations past would have died from their acute illness. While the concept of " brain death " as death of the person has finally gained almost universal acceptance in the medical, legal, and public sectors, there are still a number of vigorous critics. Persistent vegetative states have become a still more perplexing issue for medical ethics. This article is intended to provide a brief overview of the salient arguments in these debates, followed by the author's analysis of the issues according to the metaphysical principles of Aristotle and St. Thomas Aquinas. THE BRAIN DEATH DEBATE Up until the 1960s, the diagnosis of death was relatively straightforward. Dea.th occurred when the heart irreversibly stopped. With cessation of blood flow, the first organ to become irreversibly damaged is the brain, with the other body tissues succumbing shortly thereafter. There is, therefore, the possibility of a critical period of a few minutes during which the only irreversibly damaged organ is the brain. The heart still has the potential for being revived, since it is driven by its own intrinsic pacemaker, and not by the brain (the role of which is merely one of moditlating the heart rate) . If the lungs were ventilated mechanically, then the heartbeat and blood flow could continue, and the non-neural tissues of the body could remain a.live. 24 BRAIN DEA'.rH, VEGETATIVE STATE, AND DEMENTIA 25 With the advent of advanced cardiopulmonary resuscitation and improved mechanical respirators in the 1950s, this condition passed from a theoretical possibility to an increasingly common reality in hospital intensive care units. The initial confusion concerning the nature of this state is reflected in the various terms that have been used to describe it: "co11w depasse ",1· 2 "irreversible coma ",3• 4 "brain death ",5 and" cerebral death." 6• 7 In the first two terms, the word " coma" implies that the person is still alive, although unaware of self and environment, as in a very deep and permanent sleep. "Brain death " is the most commonly employed term today, although its meaning still varies from one author to the next, often without explicit definition.8 It has been used in any of three basic ways. The first implies that, within an otherwise alive body, one organ (the brajn) has died. This usage is equivalent to speaking of a "dead piece of skin " or a " dead finger " due to gangrene, in no way implying that the person himself is dead. The second usage implies a more radical concept : namely that brain death is actually a type of personal death, in addition to the standard cardiopulmonary death. This interpretation is especially prevalent in the legal sector, and is explicitly formulated in the brain death statutes of a number 1.Mollaret, P., Goulon, M: Le coma depasse. Rev. Neurol. (Paris) 101:3-15, 1959. 2 Mollaret, P., Bertrand, I., Mollaret, H.: Coma depasse et necroses nerveuses centrales massives. Rev. Neurol. (Paris) 101: 116-139, 1959. a Beecher, H. K., et al: A Definition of Irreversible Coma; report of the ad hoc committee of the Harvard Medical School to examine the definition of brain death. JAMA 205 :337-340, 1968. 4 Walker, A. E. Diamond, E. L., Moseley, J.: The neuropathological findings in irreversible coma. A critique of the "respirator brain." J. Neuropathol . Exp. Neurol. 34:295-323, 1975. 5 Korein, J. (ed.) : Brain Death: Interrelated Medical and Social Issues. Ann. N.Y. Acad. Sci., Vol. 315, 1978. s Walker, A., et al: An appraisal of the criteria of cerebral death; a summary statement. JAMA 237 :982-986, 1977. 1 Walker, A. E.: Cerebral Death. Baltimore-Munich, Urban & Schwarzenberg , 2nd ed., 1981. s Black, P. McL.: Brain Death. N. Engl. J. Med. 299 (7) : 338-344 (Part I] and 299 (8) :393-401 [Part II], 1978. 26 D. ALAN SHEWMON, M.D. of states (e.g., Kansas, Maryland, New Mexico, Virginia, Oregon , and Colorado) .0• 1° Finally, the most radical sense of the term implies that there...