Dr David Wainwright Evans, Cardiologist, Queens College, Cambridge, United Kingdom, suggests that organ donors diagnosed "brain dead" may still be alive:
"There were never sound scientific or philosophical grounds for a redefinition of death based on the loss of testable brain function while the body remains alive 1. Pressure for a viable heart for transplantation nevertheless resulted in a diagnosis of death on some such basis in Cape Town 2, in 1967. There followed “a euphoric, uncontrolled epidemic of heart transplantation around the world”3. This, together with demand for other organs which, to be viable in recipients, required that they be perfused until their removal, necessitated “the production of a set of legal and philosophical justifications”2 for procedures which would otherwise be seen as assault.
The story of how the Harvard Brain Death Committee produced, in 1968, a facilitating redefinition of death based on “irreversible coma” with “no discernible central nervous system activity” makes interesting reading4. The ease with which their novel redefinition of death became incorporated into American law, and subsequently accepted in many other countries, gave food for thought. It seemed to resist attacks upon its inconsistencies and contradictions because of its utility - indeed its perceived necessity to some transplant practices.
That is, until last year [2003]. Fittingly, the paper formally admitting that the concept of brain death - as this new form of death became widely known - “fails to correspond to any coherent biological or philosophical understanding of death” came from the Harvard Medical School too 5.
While the philosophical arguments about concepts of death may be for others, the possibility of diagnosing - with the necessary certainty - the “irreversible cessation of all functions of the entire brain, including the brain stem”, while the rest of the body remains alive, has always been the concern of the doctor. That “whole brain” definition was the requirement stipulated in the quaintly named Uniform Determination of Death Act (1981) if death were to be certified on other than the universally accepted cardiorespiratory basis. The Harvard tests - essentially of brainstem mediated reflexes and ventilator dependence, with or without EEG, in patients whose coma was believed irremediable - clearly lacked the power to make that diagnosis. The many protocols in use worldwide failed similarly. Indeed, their very number6 proclaimed the fact that the syndromes they diagnosed could not be one and the same entity7. And prominent among the variations was the apnoea test, which might lead to the misdiagnosis of respiratory centre failure if inadequately stimulating. If stringent, it might prove lethal 8.
Truog and Robinson acknowledge that many patients currently diagnosed “brain dead” do not, as a matter of fact, meet the American legal requirements governing that practice. They say that many of them retain demonstrable brain function - and that this knowledge, which should be uncomfortable to those certifying death on the basis that there is none, is set aside on the premise that it is not “significant”. That practice is reminiscent of the stance assumed by those who foisted “brain death” upon us here in the UK in 1979. They simply promulgated a set of prognostic criteria, first published in 1976, with a directive that they were to be used thenceforth as criteria for the diagnosis of death9 . The illogicality of that change of use was pointed out in 1980 10. The diagnosis (of “brain death”) was crucially dependent upon the absence of specified brainstem reflexes. Other persisting brainstem function, such as blood pressure control, was to be ignored. EEG activity was not to be sought. If demonstrated, it was to be set aside as of no “significance”. Such was the pretence to knowledge of our marvellous brain’s function which did not, and still does not, exist.
The term “brain death” was formally abandoned, in this country [the UK], in 1995 11. But comatose, ventilator-dependent patients are still being certified “dead” for transplant purposes using similar tests. These are now held to diagnose the irreversible loss of the capacity for consciousness, although no sound scientific evidence has been advanced to support that claim.
Nor, since these patients are not exposed to the anoxic drive stimulus, do they have the power to diagnose the irreversible loss of the capacity to breathe. That being so, the merits and demerits of the new conceptual basis for certifying these patients dead should be of no practical concern to the doctors who care for them.
Where requests for the organs of such patients are concerned, Truog and Robinson (like others12,13) propose the abandonment of all obfuscation about their status in the dying process. They suggest that people should be allowed to donate their organs when they become “neurologically devastated or imminently dying”, without first being declared dead. This refreshing call to face the facts has implications for the validity of the “consent” given by those led to believe that their offer of organs will not be taken up until after their death. But it may be that more will be prepared to register as prospective donors on the proposed new basis if it is fully and frankly explained - and the necessary legislation enacted after open debate."
Source:
Article by Dr. David W Evans - Retired Physician (sometime Consultant Cardiologist at Papworth Hospital)
27 Gough Way, Cambridge, CB3 9LN - and Queens’ College, CB3 9ET (DWEvansMD@tinyworld.co.uk)
Competing interests : None
References
1. Beyond Brain Death : the Case Against Brain Based Criteria for Human Death. Eds. Potts M,
Byrne PA, Nilges RG. Kluwer Academic Publishers, Dordrecht, 2000
2. Hoffenberg R. Christiaan Barnard : his first transplants and their impact on concepts of death.
BMJ 2001;323:1478-80 (and see bmj.com ‘Rapid responses’ to this article)
3. Smith T. Clinical freedom. BMJ 1987;295:1583
4. Singer P. Is the sanctity of life ethics terminally ill? In: Brain Death, Ed. Machado C. Elsevier Science B.V. 1995, 231-243
5. Truog RD, Robinson WM. Role of brain death and the dead-donor rule in the ethics of organ transplantation. Crit Care Med 2003;31:2391-96
6. Wijdicks EFM. Brain death worldwide : accepted fact but no global consensus in diagnostic criteria.
NEUROLOGY 2002; 58:20-25
7. Evans DW. ‘Open letter to Professor Wijdicks’, bmj.com ‘Rapid responses’ 11 Dec 2002
8. Coimbra CG. Implications of ischemic penumbra for the diagnosis of brain death. Braz J Med Biol Res 1999;32:1479-87
9. Conference of Medical Royal Colleges and their Faculties in the UK. Memorandum on the diagnosis
of death. BMJ 1979;I:332
10. Evans DW, Lum LC. Brain death. Lancet 1980 (November 8th):1022
11. Working Group convened by the Royal College of Physicians and endorsed by the Conference of
Medical Royal Colleges and their Faculties in the United Kingdom. Criteria for the diagnosis of brain stem death. J Roy Coll Physns Lond 1995;29:381-2
12. Kerridge IH, Saul P, Lowe M, McPhee J, Williams D. Death, dying and donation : organ transplantation and the diagnosis of death. J Med Ethics 2002;28:89-94
13. Woodcock TE. New act regulating human organ transplantation could facilitate organ donation.
BMJ 2002;324:1099
Articles
Aucun commentaire:
Enregistrer un commentaire