Why the Concept of Death is Valid as a Definition of Brain Death

Statement by the Pontifical Academy of Sciences

The Notion of Brain Death

The notion of ‘brain death’ was  introduced to refer to a new  criterion for the ascertainment of  death (able to  go  beyond the  criteria relating to  the heart and breathing and the criteria relating to the  destruction of the  soma) that had become evident with new discoveries about the working of  the brain and its  role  within the body, as  well as necessary with the changed clinical situations brought about by the  use  of the ventilator and the possibility of sustaining human organs despite the loss of the unity of the organism as a whole.

Brain Death  is Death

Brain death has been a highly important and useful concept for  clinical medicine, but it continues to meet with resistance in certain circles. The reasons for this resistance pose questions for  edical neurologists, who are perhaps in the best position to clarify the pitfalls of this controversial issue. To achieve consistency, an important initial clarification is that brain death is not a synonym for  death, does not imply death, or  is not equal to death, but ‘is’ death.

‘Coma’, the ‘Persistent Vegetative State’,  and  the ‘Minimally Conscious State’ are not  Brain Death

The inclusion of the term ‘death’ in brain death may constitute a central problem, but the neurological community (with a few exceptions) acknowledges that something essential distinguishes brain death from all other types of severe brain dysfunction that encompass alterations of consciousness (for example, coma, vegetative state, and minimally conscious state). If the criteria for brain death are not met, the barrier between life and death is not crossed, no matter how severe and irreversible a brain injury may be.

Brain Death is the Death  of the Individual

The concept of brain death does not seek  to promote the notion that there is more than one  form of death. Rather, this specific terminology relates to a particular state, within a sequence of events, that constitutes the  death of an individual. Thus brain death means the irreversible cessation of all the  vital activity of  the brain (the cerebral hemispheres and the brain stem). This involves an irreversible loss of function of the brain cells and their total, or near total, destruction. The  brain is dead and the functioning of the  other organs is  maintained directly and indirectly by  artificial means. This state results solely and specifically from the use of modern medical techniques and, with only   rare exceptions, it  can only be maintained for a limited time. Technology can preserve the organs of a dead person (one appropriately pronounced dead by neurological criteria) for a period of time, usually only hours to days, rarely longer. Nevertheless, that individual is dead.

Death  is the End of a Process

This process begins with an irreversible fact  of health, namely the beginning of the failure of the integrative functions exerted by the brain and brain stem on the  body. It ends with brain death and thus the  death of the individual. Generally, this process involves an uncontrollable and progressive brain edema, causing the  intracranial pressure to rise. When the  intracranial pressure exceeds the systolic blood pressure, the heart is no  longer capable of pumping blood through the brain. The swollen brain becomes compressed within its rigid ‘shell’, the skull, and herniates through the tentorium and the foramen magnum, which eventually totally blocks its own blood supply. Brain death and the death of the individual takes place as  the  end of this process. There is a second process which begins with the eath of the individual and involves the  decomposition of the  corpse and the ying of all the cells. The ancients were aware of these two  processes and knew, for example, that hair and nails continue to grow for days after death. To think today that it is necessary to maintain the sub-systems of a corpse receiving artificial  support, and to wait for the death of all the cells in the body before pronouncing the  death of an individual would be to confuse these two  processes. This latter approach has been termed ‘exaggerated treatment’ or, more specifically, the slowing down of the inexorable decomposition of a corpse through the use of artificial instruments.

The Consensus on  Brain Death

The criterion of brain death as the death of an individual was established about forty years ago and since that time consensus on this criterion has increasingly grown. The most important academies of neurology in the world have adopted this criterion, as have most of the developed nations (the USA, France, Germany, Italy, the UK, Spain, the Netherlands, Belgium, Switzerland, Austria, India, Japan, Argentina and others) that have addressed this question. Unfortunately, there is insufficient explanation by the scientific world of this concept to public opinion which should be corrected. We  need to achieve a convergence of views and to establish an  agreed shared terminology. In addition, international organisations should seek to employ the same terms and definitions, which would help in the  formulation of legislation. Naturally, public opinion must be  convinced that the application of the criterion of  brain death is carried out with the maximum rigour and efficacy. Governments should ensure that suitable resources, professional expertise and legislative frameworks are  provided to ensure this end.

Statistics on Brain Death

In the USA, most of the  statistics on cases of the  diagnosis of recognised brain death since its full  definition, its application, and the  clinical histories involved are   generally available in organ procurement  offices. The  Mayo Clinic has information on  about 385  cases (years 1987-1996). Flowers and Patel (Southern Medical Journal 2000; 93:203-206), reported on  71 individuals who met the  clinical criteria of brain death and then were studied by the use   of  radionuclide brain scans. No blood flow  was  demonstrated in  70 patients and in 1 patient arterial blood flow was  present on  the initial evaluation but disappeared 24 hours later. The authors concluded that using established medical criteria the accuracy of the diagnosis of brain death was 100%. The famous Repertinger meningitis case ironically demonstrates that it is possible to keep a body and organs perfused for  a long period of time. One possibility is that this patient may not have been brain dead for a long period of time (cf. the detailed discussion on this possibility during the meeting and question 15,  p. LXIX ff.). Another possibility is that this represents a valid case of  brain death since all of the cinical tests were performed to ascertain brain death except the apnea test. The absent evoked potentials and the flat EEG were consistent with brain death. If this was a validly documented case of brain death, it makes the  point that in extraordinarily rare exceptions this kind of case occurs. However, many years have passed since this case, there is a great deal of uncertainty about it, and one cannot generalise from it to invalidate the criteria for brain death. With the technologies available in modern intensive care units, we  may see  more of  such prolonged cases, as technological capacity develops to reproduce some of the  functions of the  brain stem and hypothalamus in the  integration and coordination of all the  subsystems of the  body. The neurological community does not believe that this case disturbs the  conceptual validity of brain death as being equivalent to human death.

A Counterintuitive Reality

The history of science and of medicine contains many discoveries that are contrary to our perceptions and seem counterintuitive. Just as it was  difficult for common sense to accept, at the time of Copernicus and Galileo, that the  earth was  not stationary, so  it  is sometimes difficult now for  people to accept that a body with a  pumping heart and a pulse is ‘dead’ and thus a corpse; ‘heart-beating death’ appears to defy  our common sense perceptions. In part, this is because the dead brain, like the moving earth, cannot be seen, conceptualised, or experienced by the onlooker. Indeed, the common man does not easily accept that a deep sleep-like state with a heartbeat, accompanied by electrocardiogram activity, is death. Since the use of medical technology is so ubiquitous, it is easy to fail to comprehend that a ventilator machine is a necessary intermediary in maintaining this state. This may give rise to a deep-seated reluctance both to abandon brain-dead individuals and to accept the  removal of organs from their bodies for the purposes of transplantation.

Organ Transplantations

The concept of brain death has been at the centre of a philosophical and clinical debate, especially after advances made in the  field of transplantations. In particular, it has been asked whether this criterion – and this is the  view,  for  example, of Hans Jonas – was introduced to favour organ transplantations and is influenced by a dualistic vision of man that identifies what is specific to man with his cerebral activities. Yet, as emerged during discussions of the meeting, the criterion of brain death is compatible at a philosophical and theological level with a non-functionalist vision of man. St Augustine himself, who certainly did  not identify the brain with the mind or the soul, was  able to say that when ‘the brain by which the  body is governed fails’, the soul separates from the body: ‘Thus, when the  functions of the brain which are, so  to  speak, at the  service of the soul, cease completely because of some defect or perturbation – since the messengers of the sensations and the agents of movement no  longer act –, it is as if the soul was  no longer present and was not [in  the  body], and it has gone away’ (De Gen.  ad  lit., L. VII, chap. 19; PL 34, 365). Indeed, the criterion of brain death is in conformity with the ‘sound anthropology’ of John Paul II, which sees death as the separation of the soul from the body, ‘consisting in the total disintegration of that unitary and integrated whole that is the personal self’. Thus, in relation to the criterion of brain death, the Pope was  able to declare: ‘the criterion adopted in more recent times for  ascertaining the fact of death, namely the complete and irreversible cessation of all brain activity (in the  cerebrum, cerebellum and brain stem) if rigorously applied, does not seem to conflict with the  essential elements of a sound anthropology’ (Cf. Address of 29 August 2000 to the 18th International Congress of the  Transplantation Society).

From a clinical point of view, almost the  whole of the medical community  agrees that the  concept of brain death as death should not serve an ulterior purpose (specifically: organ transplantation). Indeed, the ascertainment of brain death, which in historical terms was the result of the independent study of the  brain, preceded the first transplantation procedures and thus was (and therefore is) unconnected with the related subject of transplants (cf., e.g., S. Lofstedt and G. von Reis, ‘Intracranial lesions with abolished passage of X-ray contrast throughout the  internal carotid arteries’, PACE,

1956, 8, 99-202). Few physicians are convinced that the removal of organs from brain-dead individuals amounts to murder, and there is no reasonable legislation that adopts this point of view. The advent of cardiac and hepatic transplantation in the 1960s, and the need for organs from heart-beating donors to ensure successful results, generated an evident relationship between brain death and transplants. In the future, it is possible and to be hoped, that this relationship will diminish with new  discoveries in the  use  of natural non-human and artificial organs.

Unsound Arguments

Most of the arguments against brain death are not sustainable and are incorrect diversions when scrutinised from a neurological perspective. For example, the erroneous or imprecise application of the criteriaof brain death, the fact that the neurological examination in individual cases may be misinterpreted, or variations in the criteria chosen by specialist groups, can all too easily be used as spurious arguments against the concept.

The  Apnea Test

The claims that apnea testing poses a  risk to the patient are largely invalid when the testing is  performed properly. Authorities should ensure that apnea testing is always carried out with the maximum of professional and technological expertise, and dedicate resources to this end.

Irreversible Situations:  All Death  is Brain Death

Assertions as to the existence of ‘awakenings’ from brain death have been used to discredit the concept and to prolong artificial ventilation, feeding  and medical support in the hope of a recovery. A small number of cases of brain-dead individuals maintained in this state with ventilators and other medical measures for weeks, or  even years, have given rise to unfounded claims that these subjects were in conditions other than death. In reality, as observed above in the section on ‘statistics on  brain death’, where the proper diagnostic criteria have been employed all such assertions are not valid.

Pregnancy

Pregnancies have been carried to term in brain-dead mothers. These cases are exceptional and do not involve potentially reversible conditions different from brain death. The mother’s uterus and other organs are  being supported as a technical vessel for  pregnancy, in much the same way  that the  heart or the kidneys are kept perfused. Thus, it is possible for an individual who is brain dead to give birth, if maintained with a ventilator, or other measures, for  a certain period.

Antidiuretic and  Other  Pituitary Hormones

Other spurious arguments, such as the residual excretion of antidiuretic and other pituitary hormones in some cases of brain death, refer to tranient phenomena, and are  technical arguments that can be  dealt with on a practical level. There is no need for every  single cell inside the  cranium to be dead for  brain death to be confirmed.

Axon Regeneration

Recent reports of axon regeneration in patients with severe brain damage (which require corroboration and more study) are not pertinent to brain death.

Recovery Excluded

It follows, as mentioned earlier, that there is no chance of recovery from brain death and that discussions regarding recovery from various states of coma must be distinguished from brain death.

The Need for an Expert Neurological Examination

If the criteria of brain death are  rrectly applied, and if the  neurological examination is carried out correctly by an  experienced physician, then full reliability can be achieved. As mentioned above, there have been no documented exceptions. The neurological examination evaluates consciousness and reflexes to confirm death of  the  neurons involved in hese functions. Although every  neuron in the central nervous system is not assessed during the examination, as stated earlier it is not necessary for absolutely all neurons to be dead for brain death to be reliably diagnosed. In a sedated or previously sedated patient, the lack of perfusion of the brain must be demonstrated for  brain death to be ascertained beyond all doubt.

The Loss of Heart Activity

When the cardiologist pronounces death as a result of cardiac standstill, the diagnosis is less certain than in the circumstance of brain death. Many documented cases exist of patients pronounced dead after failure of cardiac resuscitation who have subsequently been discovered to be alive. It should be further stated that the traditional definition of natural loss of heart activity as ‘death’ is not satisfactory because it is now possible to keep the  heart beating by artificial means and blood circulation to the brain can be maintained artificially to a brain that is dead. Confusionarises from the presence of mechanical systems that artificially replace the role of  the brain as  the generator of  the functioning of  essential organs.

Therefore, brain death is a much more certain diagnosis than heart death. The  reluctance to accept brain death may be mostly related to the  fact  that it is a relatively new  concept (the invention of the ventilator by Ibsen took place fifty-six years ago) compared to the traditionally accepted notion of cardiac and respiratory arrest.

The Loss of Breathing

If one proposes that the loss of spontaneous breathing defines death, then all brain-dead patients are, by definition, ‘dead’. When the patient has been pronounced dead after the application of the appropriate criteria of brain death, the decision to continue with ventilation can only be justified with reference to the life and wellbeing of another person.

No Ventilator, No Heart Activity

If one removes the ventilator from a brain-dead patient, the body under- goes the same sequence of events and physical dissolution as occurs in an individual who has undergone loss  of heart activity.

Artificial Instruments

Thus, it is as illogical to  contend that death is the loss of heart activity as it is to affirm that the loss of kidney activity is death. Indeed, both renal activity (through dialysis) and heart activity (with a non-natural instrument) can be supported artificially, something that is impossible in the  case of the brain: no  artificial instrument exists that can reactivate or replace the  brain after it has died.

No  Circulation to the Brain Means Brain Death

One does not have to be a Cartesian to assert the  central importance of the brain. Today, after advances in our knowledge of  the workings of the brain, it is the medical-philosophical view that the body is ‘directed’ by that marvellous organ, the brain. Certainly, we are not a ‘brain in a vat’ but it has to be recognised that the  brain is the  receiving centre of all sensory, cognitive, and emotional experiences and that the brain acts as the neural central driving force of existence. We must acknowledge that the loss of circulation to the brain causes death. This loss of circulation can be documented in virtually all cases of brain death if tests are performed at the  proper time.

The  Camouflaging of Death

In reality, the ventilator and not the individual, artificially maintains the appearance of vitality of the body. Thus, in  a condition of brain death, the so called life of the  parts of the body is ‘artificial life’ and not natural life. In essence, an artificial instrument has become the principal cause of such a non-natural ‘life’. In this way, death is camouflaged or masked by the use of the  artificial instrument.

Education and Brain Death

One of the tasks of physicians in general and neuroscientists is to educate the  public about discoveries in this field. As regards the concept that all death is brain death, this task may be difficult, but it is our duty to continue in such an endeavour.

At a specific level, the relatives of brain-dead individuals should be told that their relative has died rather than that he is ‘brain-dead’, with the accompanying explanation that the support systems produce only an appearance of life. Equally, the terms ‘life-support’ and ‘treatment’ should not be employed because in reality support systems are  being provided to a corpse.

A. Battro, J.L. Bernat, M.-G. Bousser, N. Cabibbo, Card. G. Cottier, R.B. Daroff, S. Davis, L. Deecke, C.J. Estol, W. Hacke, M.G. Hennerici, J.C. Huber, Card. A. López Trujillo, Card. C.M. Martini, J. Masdeu, H. Mattle, J.B. Posner, L. Puybasset, M. Raichle, A.H. Ropper, P.M. Rossini, M. Sánchez Sorondo, H. Schambeck, E. Sgreccia, P.N. Tandon, R. Vicuña, E. Wijdicks, A. Zichichi