Brain stem death


Brain stem death

Brain Stem Death is the specific formulation of the concept of brain death formally adopted in the UK in 1995.

Diagnosis

The diagnostic features of brain stem death are a deep coma, dependence for oxygenation on a mechanical ventilator, and the absence of specified reflexes which depend upon circuits within the brain stem. Formal rules for its diagnosis were first published in 1976, by the UK Conference of Medical Royal Colleges, acting with advice from the Transplant Advisory Panel. They specified tests for the pupillary light reflex, the corneal reflex, vestibulo-ocular reflex, motor reflexes with brain stem arcs, the gag reflex and reflex response to bronchial stimulation. Reversible causes of coma (such as drugs, hypothermia, metabolic and endocrine abnormalities) had to be excluded. Ventilator dependence was confirmed by disconnection for long enough to ensure that the medullary respiratory centre was exposed to a powerful hypercapnic drive stimulus (PaCO2 ≥ 6.65kPa). Its exposure to the ultimate anoxic drive stimulus was avoided by pre-oxygenation and continuing oxygenation by diffusion. No testing of the medullary centres controlling heart-rate and blood pressure was required. The prescribed tests were required to be repeated, at an unspecified interval, "to ensure that there has been no observer error".

With only minor modifications, these rules for the diagnosis of the syndrome have become the basis for Codes of Practice governing the procurement of organs for transplantation which have been published by the United Kingdom Department of Health between 1980 and 1998. They are currently under further review.

Prognosis and Management

Except when diagnosed too early - when the absence of demonstrable synaptic function cannot be equated with irrecoverability - final circulatory arrest occurs within a few days in almost all cases. However, there have been exceptional long-term survivals and, most significantly, some pregnant women have been kept alive to become mothers several weeks after they were, or could have been, diagnosed "brain stem dead". Brain stem death as diagnosed by the UK Code of Practice rules may therefore be seen as a very late stage of the dying process, although not as late as that described - as "le coma dėpassė" - by Mollaret and Goulon in 1959, whose syndrome included loss of blood pressure maintenance and control (circulatory collapse).

Identification of this syndrome was held, by the Conference of the Medical Royal Colleges in 1976, to require withdrawal of "further artificial support" - particularly fruitless mechanical ventilation of the comatose patient - thus "sparing relatives from the further emotional trauma of sterile hope". The diagnostic criteria being accepted by this authoritative body as "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", no legal problems with this withdrawal of life-support measures, in the sole interests of the patient and his relatives, were likely to be encountered.

Controversial aspects

Perhaps influenced by the ad hoc Harvard Committee report of 1968 and the later Minnesota study, death of the brain stem, as diagnosed by purely bedside tests, was identified with brain death by Conference in their 1976 publication. In a Memorandum published in 1979, the same criteria were declared sufficient for the diagnosis of death itself, despite the presence of a normally regulated circulation and continuing (artificially supported) respiration. No scientific or philosophical basis for this change of use of the essentially prognostic criteria was given.

In 1995, Conference abandoned the looser term 'brain death', in favour of the "more correct" term 'brain stem death' thenceforth. However, it was not made clear that use of the term should not be seen as implying the diagnosis of death of the whole of the brain stem (however defined anatomically) in the de facto pathological sense - there being no requirement to test the medullary cardiovascular or oesophageal motility centres or to challenge the respiratory centre to the ultimate anoxic drive stimulus (even the specified apnoea testing being potentially lethal). The brain stem formulation of brain death is based on the theory that the reticular activating system, part of which is located within the brain stem, is essential for the generation of consciousness. This is important because Conference continued to underwrite the diagnosis and certification of death on the basis of their essentially prognostic criteria, claiming that satisfaction thereof meant that there could never again be any possibility of spontaneous breathing or of consciousness in any form. Whatever one may think of that particular concept of human death, a minority view within the profession holds that without subjecting the respiratory centre to the most extreme determination of persistent apnoea - a critically low oxygen tension in the arterial blood - one cannot be certain of the irreversible loss of the capacity to breathe spontaneously. Others object that the generation of consciousness is not sufficiently understood to invoke it in this context. Finally, even if a quintessential role for brain stem arousal mechanisms is accepted, some objectors feel that, as they are not directly testable, they can be considered permanently functionless only if the whole of the brain stem is shown to be destroyed.

A Working Group was set up by the UK Academy of Medical Royal Colleges in 2004 to revisit the guidelines, partly in light of anomalies in the way the tests are carried out in practice. To date (June 2008) the Working Group has not issued its formal report.

For a discussion of the general concept of a neurological rather than a cardiac definition of death, see the article on brain death.

References

*Conference of Medical Royal Colleges and their Faculties in the UK. Diagnosis of brain death. British Medical Journal 1976;2:1187-8
*Cadaveric organs for transplantation - a Code of Practice including the diagnosis of brain death. UK Department of Health, February 1983
*A Code of Practice for the diagnosis of brain stem death. UK Department of Health, March 1998
*Mollaret P, Goulon M. Le coma depasse. Revue Neurologique 1959;101:3-15
*Report of the Ad Hoc Committee of the Harvard Medical School to examine the definition of brain death - 'A definition of irreversible coma'. JAMA 1968;205:337-40
*Conference of Medical Royal Colleges and their Faculties in the UK. Memorandum on the diagnosis of death. British Medical Journal 1979;1:332
*Conference of Medical Royal Colleges and their Faculties in the UK. Criteria for the diagnosis of brain stem death. Journal of the Royal College of Physicians of London 1995;29:381-2
*Siegler M, Wikler D. Brain death and live birth. JAMA 1989;248:1101
*Coimbra CG. Implications of ischemic penumbra for the diagnosis of brain death. Brazilian Journal of Medical and Biological Research 1999;32:1479-87
*Evans DW, Hill DJ. The brain stems of organ donors are not dead. Catholic Medical Quarterly 1989;40:113-121
*Beyond brain death - the case against brain based criteria for human death. Eds. Potts M, Byrne PA, Nilges RG. Kluwer Academic Publishers, Dordrecht, 2000
*Finis vitae - is brain death still life? Ed. de Mattei R. National Research Council of Italy, Rubbettino Editore, 88049 Soveria Mannelli (Catanzaro), 2006
*bmj.com - articles and 'Rapid responses', under headings such as 'brain stem death' and 'brain death'
*Brief review: History, concept and controversies in the neurological determination of death. Baron et al. Canadian Journal of Anesthesia 53:602-608 (2006) http://www.cja-jca.org/cgi/content/full/53/6/602

External links

* [http://legalwikipro.com/wiki/index.php?title=Death_(OK) LegalWikiPro Article on Brain Death, Organ Donation and Civil Action for Mishandling of Dead Body under Oklahoma law]


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Brain death — is a legal definition of death that emerged in the 1960s as a response to the ability to resuscitate individuals and mechanically keep the heart and lungs working. In simple terms, brain death is the irreversible end of all brain activity… …   Wikipedia

  • death — /deth/, n. 1. the act of dying; the end of life; the total and permanent cessation of all the vital functions of an organism. Cf. brain death. 2. an instance of this: a death in the family; letters published after his death. 3. the state of being …   Universalium

  • death — n: a permanent cessation of all vital bodily functions: the end of life see also brain death, civil death ◇ Death is usu. defined by statute and for purposes of criminal homicide has been held to include brain death. Merriam Webster’s Dictionary… …   Law dictionary

  • Brain tumor — Classification and external resources Brain metastasis in the right cerebral hemisphere from lung cancer shown on T1 weighted magnetic resonance imaging with intravenous contrast …   Wikipedia

  • Brain herniation — Classification and external resources MRI showing injury due to brain herniation ICD 10 G …   Wikipedia

  • Brain abscess — Classification and external resources Brain abscess in a patient with CSF shunt; from Jamjoom et at., 2009[1] …   Wikipedia

  • Brain–computer interface — Neuropsychology Topics Brain computer interface …   Wikipedia

  • death — The cessation of life; permanent cessations of all vital functions and signs. Numerous states have enacted statutory definitions of death which include brain related criteria. For example, many states have adopted, sometimes with variations, the… …   Black's law dictionary

  • death — The cessation of life; permanent cessations of all vital functions and signs. Numerous states have enacted statutory definitions of death which include brain related criteria. For example, many states have adopted, sometimes with variations, the… …   Black's law dictionary

  • brain — n. & v. n. 1 an organ of soft nervous tissue contained in the skull of vertebrates, functioning as the coordinating centre of sensation, and of intellectual and nervous activity. 2 (in pl.) the substance of the brain, esp. as food. 3 a a person s …   Useful english dictionary


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.