"Brainstem death," "brain death" and death: a critical re-evaluation of the purported equivalence.

• Author: Shewmon, D. Alan

ABSTRACT: The author challenges brain-based diagnoses of death by re-examining the concept of death, its definition, the anatomical criterion, and the clinical signs or tests. Dr. Shewmon challenges the fundamental assumptions underlying brain death: (1) that the brain is the body's "critical system"; and (2) that the body even has a localized "critical system." He does not redefine death, but shifts the anatomical criterion from a single focus (the brain) to the entire body. The clinical tests correspondingly shift from those implying loss of brain function to those implying thermodynamically supracritical microstructural damage diffusely throughout the body. He concludes that the notion of "brain death" as bodily death is logically and physiologically incoherent, and that its replacement by something scientifically more credible would promote not only the sanctity of life, but ironically even transplantation as well.

Introduction

Statement of the Problem

Brain-based diagnoses of death are now legally recognized in most developed countries of the world. This widespread consensus is split into two basic camps, following either the U.S. "whole brain" or the British "brainstem" formulation of so-called "brain death." As nicely summarized by Pallis and Harley,(1) the essential points of the disagreement over detail are twofold:

(1) What is "the critical system of the body's critical system"? (That is, what part of the brain is to the brain as the brain is to the body?)--and

(2) Can physicians identify the death of the brainstem by exclusively clinical (non-instrumental) methods?

It may come as a surprise to some readers that I shall not be arguing here the United States' side of that debate. Rather, my goal is much more radical: to challenge certain fundamental assumptions common to both sides, specifically that:

(1) the body's "critical system" is the brain, and

(2) the body even has a localized "critical system."

Background

First some background. As a neurologist in a major academic transplant center, I have extensive clinical experience with "brain death." And as a convert from atheism to theism, I have a particular interest in the relationships among brain, mind, body, and soul.

In the early and mid-1980s I was a strong proponent of the notion that human death was essentially neurological in nature, that death of the entire brain was death of the person, and that the most convincing rationale for that equivalence also happened to imply that "neocortical death" was equally death.(2) This opinion evolved to a modified version of "whole brain death," which I presented in 1989 at the Pontifical Academy of Sciences.(3) Since then, I have come to reject all brain-based formulations of death.(4) Thus, I am thoroughly conversant first-hand with the arguments on all sides of the debate.

Until the turn of the decade, most people thought that "brain death" was a settled issue; it no longer is. An increasing number of experts have begun to re-examine critically and to reject various key underlying assumptions.(5)

Of particular interest is the recent public debate in Germany over incorporating "brain death" into statutory law.(6) A surprising number of intellectuals have argued against it, not the least of whom is the archbishop of Cologne, Joachim Cardinal Meisner, who stated officially that "the identification of brain death with death of the person is from a Christian point of view no longer justifiable."(7) As a testimony to the intensity of the controversy, the finally adopted law merely specified "brain death" as a legal requirement for organ harvesting without actually declaring it to be death.(8)

The position against "brain death" that will be advanced here must not be misconstrued as necessarily anti-transplantation.(9) The equating of "brain death" with death was in retrospect quite unnecessary, even for the utilitarian purposes which historically inspired it.(10) Through a variation on the "non-heart-beating donor" approach,(11) it is possible to remove vital organs from a patient just disconnected from extraordinary ("disproportionate") means of support, after final cessation of heartbeat and circulation but before actual death (to be defined below), in such a way that death is neither caused nor even hastened by the organ removal. A number of other ethical prerequisites must of course also be assumed: (1) that the decision to discontinue the extraordinary means (typically a mechanical ventilator) be appropriate and ethical on its own ground (and irreversible coma due to extensive brain destruction seems a particularly appropriate circumstance), (2) that the decision to discontinue extraordinary means be not influenced by considerations of organ donation, (3) that fully informed consent be given and the donation of organs be truly voluntary (let us prescind, for the sake of focus, from ethical complications introduced by proxy decisionmaking, such as with pediatric donors or adults who had not previously expressed an intention concerning donation).

Whether these requirements for theoretical legitimacy can always be fulfilled in practice is an important separate issue, which could in some cases exclude this approach. But assuming moral licitness, the procedure would not begin until after final (though not yet irreversible) circulatory standstill following discontinuation of the ventilator and after a latency sufficient for moral certainty that the heart will not spontaneously start beating again if the body is left undisturbed (probably a couple of minutes would suffice). With prior informed consent, arterial catheters could already have been placed, through which to perfuse organs of interest with a cool preservative to minimize their deterioration from lack of oxygen. Although the heart is still in principle resuscitatable, if the foregoing of the ventilator is ethical, all the more so would be the foregoing of resuscitation immediately thereafter. In this very restricted and well defined context, excision of the non-beating heart (which if left alone would remain permanently non-beating) in no way alters the circulation-less body's physiology during the remaining few minutes of the dying process. Thus, transplantation techniques could be modified (and in some centers already have been) to fall under the moral rubric of donation inter vivos rather than of the Fifth Commandment or the so-called "dead-donor rule."(12) Significantly, this was in fact precisely how the first successful heart(13) and liver(14) transplants were carried out in 1967, prior to the legal equation of "brain death" with death.(15)

This approach to transplantation deserves further research into means of improving outcomes as well as urgent and intense study by expert moralists. I mention this alternative here, not because I am on any sort of promotional bandwagon, but in order to encourage such study and to reassure the transplant community that the conceptual demise of "brain death" would not necessarily entail the demise of organ transplantation, although it would surely require a radical change in the modus operandi for obtaining donor organs.

Moreover, the requirement of donor "brain death" may have paradoxically hindered rather than facilitated the transplantation enterprise. There is good reason to believe that a significant factor contributing to the low rate of signing of organ donor cards has been a widespread instinctive suspicion that "brain dead" donors are really still alive (though fatally injured),(16) and that historically the "brain death" concept was manufactured through "conceptual gerrymandering"(17) for purely utilitarian purposes.(18)

Concept of Death

Let us turn, then, to the key ontological question: Is a dead brain equatable with a dead person?

One must distinguish three levels of consideration, which are unfortunately often confused:(19)

(1) the definition of death--an essentially philosophical matter;

(2) the anatomical criterion which instantiates this definition--a hybrid philosophical/medical matter; and

(3) the clinical signs or tests to determine the occurrence of that anatomical criterion in concrete cases--a purely medical matter.

The United States vs. United Kingdom debate is at the second and third levels, whereas this article will focus on the first and second. After all, what good are valid diagnostic criteria for an invalid concept?

Three distinct concepts of death run throughout the "brain death" literature:(20)

(1) Sociological: loss of conferred membership in human society--an arbitrary, culturally relative, social construct, which presently happens to be brain based. Clearly this is incompatible with the Judeo-Christian view of human life and death.

(2) Psychological: loss of essential human properties or personhood, independent of the vital status of the body. It is species-specific and applies to many cognitively disabled human beings apart from the "brain dead." It reduces personhood to consciousness, often in turn reduced to a material product or epiphenomenon of brain electrochemical activity. It is also clearly inimical to the Judeo-Christian view.

(3) Biological: loss of integrative unity of the body. This is species nonspecific and corresponds to the ordinary understanding of "death." It is harmonious with the Judeo-Christian heritage and underlies the mainstream theory of "brain death."

According to the Aristotelian-Thomistic philosophical tradition, the principle of unity of any living thing is its substantial form or soul. In humans this also has a spiritual dimension, so that the principle of personhood is one and the same with the principle of substantial unity of the body. This view contrasts markedly with the Platonic notion of soul as a pure spirit "imprisoned" in the body, and with Descartes' equation of soul with a conscious mind and the body with an organic machine.

The formulation of soul as substantial form of the body was even dogmatically defined by the...