To say that a brain is dead, when only a very small part of it has been tested, is not to make a scientific statement. To say that all brain functions are permanently absent when they have not been rigorously sought, and evidence of their persistence has been overlooked or misconstrued, stretches scientific credibility altogether too far and borders on intellectual dishonesty. The effective proscription of available diagnostic techniques which might demonstrate remaining life in brains thus called “dead” suggests a lack of proper scientific willingness to challenge hypotheses. Inevitably, this raises thoughts of a “cherished hypothesis” which, for reasons unconnected with the pursuit of knowledge, must not be allowed to fall.
So it was, with “brain death” in the U.K. The notion that death of the brain could be safely diagnosed, by simple bedside tests, while the body was still alive, was based not on science but on wishful thinking. Under pressure to provide viable hearts and livers for transplantation, the professional body (the Conference of the Medical Royal Colleges and their Faculties in the U.K.) which advises Government in Britain, espoused that notion of “brain death” (Conference, 1976) and, on the basis of specious arguments and a false premise, declared (Conference, 1979) that “brain death”—as diagnosed by their simplistic protocol—was death. Thenceforth, for the first time in the U.K., it was possible to certify as dead patients who, although dependent upon mechanical ventilators for their breath, had intact circulations perfusing their undeniably living bodies thanks to their still naturally beating hearts. Thus was born “death by protocol,” there being no change in physiological status as a pen-stroke made a patient a “beating-heart cadaver.” So crude a device seemed to some of us more appropriate to a totalitarian régime than a democratic society. It was introduced by stealth (Singer, 1995) and foisted upon the professions and public by propaganda. But it served its purpose in side-stepping the ethical and legal difficulties associated with the acquisition of transplantable hearts and livers. Thus was spawned the U.K. explosion of expensive and disruptive activity in this misguided field of surgical endeavour.1
That Conference ever gave its backing to so shaky a concept and practice was—in an age when medicine was supposed to be becoming more scientifically based—both regrettable and surprising. To its credit—and providing comfort to those who like to believe that science and reason ultimately prevail—it did, eventually, recognize the untenability of its premise and recant (Conference, 1995). By abandoning, in 1995, its earlier claim that its protocol was capable of diagnosing brain death, Conference may one day prove to have been in the forefront of an
international movement which consigned “brain death” to the dustbin as a mere invention for the purposes of transplantation.2
I. THE SCIENCE
The essential facts with regard to the diagnosis of the death of the brain are few. The most important is that comparatively little is yet known about the basic working of this remarkable organ. Its functions are so many and so wonderful that it is generally regarded as the organ which most particularly distinguishes Man from the other animals. Thanks to the development of new techniques, progress is now being made in locating some of its functions but others remain, at present, inaccessible to scientific investigation. One of these ill-understood functions is consciousness.
There is still no convincing theory of consciousness (Pallis, 1996) and it is, therefore, not surprising that there is no means of testing for its presence (in some form); still less is there any way of ascertaining the permanent loss of the capacity for its return (under some circumstances) in those who appear deeply comatose. The theory of consciousness upon which the U.K. version of “brain death” was based (and the current notion that “brain stem death” is death depends) was proposed some 50 years ago as a result of experiments on cats.3 Its (scientifically unwarranted) application to comatose man requires acceptance of the hidden assumption that when certain brain stem functions are absent the whole of the brain stem must be dead, i.e. that all possibly active or recoverable elements of the “arousal system”—the so-called “reticular activating system” (RAS)—within the (anatomically undefined) brain stem have been destroyed. This is because the RAS is not a discrete structure and how much of it needs to remain active for there to be any possibility of consciousness is not known. As it cannot be directly tested, it is only by implication that it can be said to be permanently out of business (unable to arouse the brain to a state of consciousness for other parts to modulate) when the whole of the brain stem is destroyed. That is not the case in organ donors whose brain stems have been certified dead prior to surgery (Evans and Hill, 1989).
Even if the bedside tests used had the power to assure us that the whole of the brain stem and all its contained RAS was really and truly dead, there is the difficulty that elements of the critical RAS exist elsewhere in the brain.4 To believe that there is never again a possibility of the return of any form of consciousness therefore requires acceptance of the additional proposition that, although untested (and currently untestable), all such potential consciousness generators are permanently out of action (destroyed) because some more primitive brain functions are absent. No truly scientific mind would entertain these propositions.
II. CLINICAL APPLICATION
The present lack of knowledge of the workings of the brain requires that due caution be exercised when clinicians are asked to diagnose its death. Nothing short of demonstration that the whole of the brain, in its every part, had not only ceased to function but had lost all capacity ever to regain function should suffice. The much-mooted alternative to this factual diagnosis of whole brain death—“death of the brain as a whole” (Pallis, 1996, p. 37)—requires that an essentialist role be granted to some part of the brain, e.g. the brain stem. This is the small primitive part of the brain which connects it to the spinal cord. There is, at present, no scientific basis for granting it such status. If it ever were shown to be the quintessential “kernel” of the brain—containing its “ON/OFF switch”—the concept that the brain “as a whole” is dead when its stem is dead would lose validity as techniques were developed to replace those brain stem functions upon which continuing activity of the rest of the brain may depend. Its function in maintaining breathing has been successfully taken over by machines for several decades and the loss of its blood pressure regulating function can be compensated for pharmacologically; it may be that its arousal function is replaceable too (Hassler, 1977, quoted by Shewmon, 1997, p. 36).
The fact is that there are, as yet, no commonly available clinical investigative techniques which can diagnose, with the necessary certainty, total, irreversible, loss of all brain functions within a few hours of the onset of coma and while the circulation persists.5 That certainty can be provided only by ascertaining the complete absence of oxygen uptake by the brain over a period of time (which depends upon temperature) sufficient to ensure tissue necrosis in every part of the brain. In practice, that means being sure that all blood circulation, to every part, has finally ceased. That requirement is satisfied by observation of the final cessation of the bodily circulation and this is the basis for the diagnosis of death of the brain (and death of the person) in more than 99% of all human deaths diagnosed and certified worldwide.
III. THE WHY AND THE WHEREFORE OF U.K. “BRAIN DEATH”
So how did it ever come to be accepted--by leaders of the medical profession, some philosophers6 and even some lawyers7 in the U.K.—that brain death could be safely diagnosed on the basis of simple bedside tests for some brain stem functions, no search of any kind for remaining life in the mass of the brain (the cerebral hemispheres) being required? The lawyers and philosophers have the ready excuse that they did not really understand. Their training did not equip them to see the flaws in the specious arguments of those in the medical profession whose advice they sought—or who thrust their ideas upon them. But, that being so, it might be suggested that they should have been more cautious, and consulted more widely, before allowing themselves to be used as instruments in a process of so profound and dangerous a nature as a change in the definition, diagnosis and certification of human death.
This brings us to the question, “Why did the medical hierarchy in the U.K. ever accept, and promulgate, the view that a patient’s life could be signed away by specialized doctors on the basis of a few bedside tests, there being no change in his clinical or physiological status between the time when he was regarded as a patient and the time when he became, notionally but very obviously not factually, a cadaver?”
(And here let us be perfectly clear that it was the [negative] responses to these tests [Conference, 1976], not all of which had to be done,8 which converted a living, comatose, patient undergoing treatment for his own good into a “brain dead” so-called “beating-heart cadaver” from whom it was deemed justifiable to remove his vital organs. Much was made of the “pre-conditions” to be satisfied before the tests were performed (Conference, 1976). But, with the exception of the last, they amounted to no more than a diagnosis of deep coma with ventilator-dependence, in the causation of which the influence of drugs, metabolic and endocrine disturbances and primary hypothermia had been excluded—conditions which may be satisfied by patients retaining a chance of recovery. The final condition was that there be “no doubt that the patient's condition is due to irremediable brain damage. The diagnosis of a disorder which can lead to brain death should have been fully established.” This final condition suggests strong bias in favor of a diagnosis of “brain death” before the validating tests are carried out. So many of the pathological processes which can lead to a patient requiring ventilation can cause mortal brain damage that this condition is essentially meaningless. It does, however, indicate the dominance of [necessarily fallible] clinical opinion [Evans and Lum, 1980] in this process of rendering, on paper, a ventilator-dependent patient “dead”).
Since the prescribed tests lacked the power to establish that even the brain stem was destroyed, and did not test the cerebral hemispheres at all, how could they have been promoted as tests for the death of the brain (and, in 1979, of the person)? Was there, perhaps, a wish to call these unfortunates “dead” before they really were—and a perceived need to justify that practice, albeit by sophistry? While Conference’s 1979 pronouncement was clearly influenced by transplant considerations, since it served no other purpose (Hill and Evans, 1993; see also Dyer, 1997), I believe it should be seen in the context of a process which started some ten or twenty years earlier. Along the way, two major and sufficiently simultaneous developments—advances in life-support and transplantation techniques—had their influence and an important misnomer manipulated thought.
IV. A LITTLE HISTORY
The problem of what to do when ventilator-dependent patients appeared to pass a “point of no return” arose in the late 1950s and became relatively common in the 1960s. It was, of course, a product of the increasingly successful resuscitation and life-support techniques which were, by then, becoming generally available. Those who worked in the rather primitive intensive care units (ICUs) of those days will remember distressing decisions, reached after specialist consultation and with the full agreement of the nursing staff and relatives, to turn off the ventilator when it was felt that there was no longer any realistic prospect of recovery, no matter how hard we tried from that point on. We did this solely in the interests of the patient and his relatives—to limit their (and possibly his) distress by allowing him to die with such dignity as might remain. We regarded this decision to withdraw pointless and possibly unkind therapy as on par with the withdrawal of any other useless and improper treatment, although the effects of such withdrawal were, of course, more immediate than those of withdrawal of, e.g. antibiotics from a patient with terminal cancer. We had no reason to believe that we were acting in any way illegally by so doing (see Skegg, 1984, pp. 179-180).
The younger and more technically enthusiastic among us found it more difficult to “let them go” than some more mature physicians and, in consequence, we often continued life-support for too long (when Nature did not step in to terminate the tragic saga for us). As the days went by, and coma seemed to deepen rather than lighten, the nursing staff continued to care for these patients with great tenderness, addressing them by name—perhaps because of some intuitive feeling that hearing might be preserved. But there might come a day when it became clear to all concerned that such a ventilator-dependent, cranially areflexic patient was too far gone to have the remotest chance of recovery. The complications which might be present at that stage need not be detailed here. Before terminating ventilation, we might agree with the nursing staff that “there's nobody in there now”—a fiction, maybe, for we could not know, but one which afforded comfort to those who might have become too deeply emotionally involved.
It was a short step from that assessment to the apparently more scientific “his brain is dead.” That readily became “he’s brain dead” and that loose but easily remembered terminology may well have manipulated thought when “brain death” became, as it did, the common name for pre-mortal syndromes of that kind. It was a great pity that some more accurate term such as “mortal brain damage” was not attached to this syndrome.9
Because these onerous decisions were being made on a variety of empirical grounds, there was a need for published consensus criteria as a basis for the discontinuation of mechanical ventilation in hopeless cases—to make the decision more comfortable for the physicians concerned and to help relatives in their acceptance, as well as to afford a basis for the defense of such decisions should they be challenged subsequently (Hill and Evans, 1993; Dyer, 1997). In essence, what was required was a set of clinical tests capable of establishing, with at least that degree of certainty appropriate to clinical practice uninfluenced by any third-party interest, that there was no prospect of recovery even if ventilation were to be continued. They would define a clinical syndrome to which was attached a hopeless prognosis.
The first such criteria were published by Mollaret and Goulon (1959). They called the pre-mortal syndrome which their criteria defined, “Le coma dépassé”—begging no questions about the extent of damage to the mortally damaged brain. Their criteria defined a much later stage in the dying process than did criteria published subsequently. The EEGs of their patients were flat. They were unreactive, unable to swallow and incontinent. They had lost their tendon reflexes as well as their ocular responses to light and touch. Most of them exhibited polyuria (due to lack of posterior pituitary hormone). Crucially, all of them had lost the ability to control their body temperature (an hypothalamic function) and to sustain their blood pressure (a brain stem function); cardiovascular collapse ensued immediately upon cessation of the intravenous infusion of noradrenaline which kept the blood pressure at a level sufficient for the heart to be able to keep going.
Mollaret and Goulon raised the question of the propriety of stopping life-support measures on the basis of such criteria which seemed to define “a frontier between life and death.” Had they chosen to call their syndrome “brain stem death,” rather than “coma dépassé” or “fourth degree coma,” it would have been a far more accurate use of the term than when it was subsequently applied (by others) to syndromes diagnosable at far earlier times in the dying process—and before brain stem control of the blood pressure had certainly been lost.
V. THE BRITISH CRITERIA FOR DISCONTINUING VENTILATION
In the UK, we had to wait until 1976 for an official pronouncement on the circumstances in which withdrawal of life-support would be appropriate. It came in the form of a consensus statement by the Conference of the Medical Royal Colleges and UK Faculties (1976). Although the stated purpose was “to establish diagnostic criteria of such rigor that on their fulfillment the mechanical ventilator can be switched off, in the secure knowledge that there is no possible chance of recovery”—a purpose of which, I believe, most of us strongly approved—their paper was most unfortunately titled “Diagnosis of Brain Death.” It recorded the agreement of its members “that permanent functional death of the brain-stem constitutes brain death,” without any attempt to justify that statement as a matter of scientific fact rather than a mere form of words commonly used to describe a well-known syndrome. It depended heavily upon the Harvard Ad Hoc Committee Report (1968)—which, as Singer (1995) has pointed out, was much influenced by transplant considerations—and upon the personal experience of those concerned with the diagnosis of “brain death” for transplant purposes.10 The fact that the published criteria “were written with the advice of the Transplant Advisory Panel” was explicitly recorded. This, and the scientifically inaccurate description of the state diagnosed by their criteria (the potentially great influence of which I did not fully appreciate at the time), should have alerted me to their true purpose and triggered a protest. But the preamble concluded with, “They (the criteria) are accepted as being sufficient to distinguish between those patients who retain the functional capacity to have a chance of even partial recovery and those where no such possibility exists”—so clear a statement, as I thought, that they were to be used for purely prognostic and contingent management purposes (with no third party consideration) that I felt no pressing need to object to the misnomer and bad science. It must also be said that, at that time, I had only rare personal involvement with chronically ventilator-dependent patients. And, crucially, I believed the possibility of cardiac transplantation coming to Papworth Hospital—the Cambridge and East Anglian Cardiothoracic Centre where I was on the Consultant Staff from 1967 until 1988—was out of the question as I had refused to help in its development and there was a Government moratorium against it (imposed after earlier disastrous adventures in this field).
THE CHANGE OF USE OF THESE CRITERIA FROM PROGNOSTIC TO
DIAGNOSTIC OF DEATH
In 1979, Conference published its edict that “the identification of brain death (as diagnosed on its 1976 criteria) means that the patient is dead.” In this way the very same criteria introduced (ostensibly) for the purely prognostic purpose suddenly accorded the power to diagnose death. No coherent arguments were advanced to justify this fundamental change of use and, significantly, no reason given for this redefinition of death by decree. Since there was no need for a new basis for diagnosing death other than as a means of side stepping the legal and moral problems associated with acquiring transplantable hearts and livers, that requirement must have been the real reason for this extraordinary and illogical pronouncement. (Contrary to what was claimed by Pallis and others, there was never any legal necessity to certify ventilator-dependent patients “dead” before discontinuing life-support in their interests alone).11
Assisted by a newly-appointed cardiologist, Terence English started cardiac transplantation at Papworth Hospital in 1979.12
In its attempt to divert attention away from the time-honored and scientifically-based means of diagnosing death—which depends on observing evidence of the final cessation of the circulation and respiration—Conference’s 1979 Memorandum cited the obviously irrelevant fact that temporary cessation of the heartbeat could not be equated with death. Mention of “spontaneous cardiac arrest followed by successful resuscitation” in this context was clearly absurd. Were they counting on most of their readership not having experience of such resuscitation? Anyone who had such experience knew that one had to get the heart going again within a very few minutes (at ordinary temperatures), or at least to maintain some circulation of oxygenated blood to the brain (by massage and ventilation) while it was stopped, if there were to be any chance of saving the patient's life. And during elective cardiac arrest for the purpose of open-heart surgery (also cited) we were very careful to maintain an adequate circulation of oxygenated blood to the brain throughout the procedure—until the heart was re-started and able to take over the circulation again. In both cases, if the heart could not be re-started, i.e. if the cardiac arrest and consequent circulatory arrest proved final (and no alternative pump was substituted), that signaled the inevitable demise of the brain—and the patient—as in the everyday case of death away from such specialized facilities.
This attempted justification was so absurd that it now seems hardly credible that so expert a panel could advance it seriously. That they did so speaks loudly for their inability to find any logical basis for the change of use they were foisting upon the professions and public.
The premise upon which Conference’s (1979) edict was based is to be found in the seventh paragraph of their Memorandum. It is there stated that “brain death represents the stage at which a patient becomes truly dead, because by then all functions of the brain have permanently and irreversibly ceased” (Conference, 1979, p. 332). In the same paragraph they invite acceptance of the notion that this state equates with religious concepts of the departure of the spirit from the body. No evidence is offered in support of either statement, the second of which may very well have influenced some religious believers. From the scientific point of view, what matters is that (as we shall see) their criteria lacked the power to diagnose the permanent loss of all brain functions; in that sense, their premise was false.
CONFERENCE’S CRITERIA FOR THE DIAGNOSIS OF DEATH ON
“BRAIN DEATH” GROUNDS
The 1979 Memorandum did not modify the 1976 protocol for their diagnosis of “brain death” and it must therefore be assumed that the syndrome referred to as “brain death” in the 1979 paper was the same as that diagnosed on the criteria published in 1976. Conference did reconsider the matter in 1981 and published (Robson, 1981) some interesting riders to the essentially unchanged protocol. The status of the doctors empowered to diagnose “brain death” was clarified; one had to be a Consultant and the other a Consultant or Senior Registrar, both with expertise in the field.13 They were given leave to omit some of the prescribed tests at their discretion. The letter recommended repetition of the tests if they “confirm(ed) brain death” but left the time interval between the two series of tests to the doctors, suggesting that it be “adequate for the reassurance of all those directly concerned.”