Medical diagnosis of death in adults: historical contributions to current controversies

When Does the Human Embryonic Heart Start Beating? A Review of Contemporary and Historical Sources of Knowledge about the Onset of Blood Circulation in Man

The onset of embryonic heart beating may be regarded as the defining feature for the beginning of personal human life. Clarifying the timing of the first human heartbeat, therefore, has religious, philosophical, ethical, and medicolegal implications. This article reviews the historical and contemporary sources of knowledge on the beginning of human heart activity. Special attention is given to the problem of the determination of the true age of human embryos and to the problem of visualization of the human embryonic heart activity. It is shown that historical and current textbook statements about the onset of blood circulation in man do not derive from observations on living human embryos but derive from the extrapolation of observations on animal embryos to the human species. This fact does not preclude the existence of documented observations on human embryonic heart activity: Modern diagnostic (ultrasound) and therapeutic (IVF) procedures facilitate the visualization of early embryonic heart activity in precisely dated pregnancies. Such studies showed that the human heart started its pumping action during the fourth post-fertilization week. A small number of direct observations on the heart activity of aborted human embryos were reported since the 19th century, but did not receive much recognition by embryologists.

The intractable problems with brain death and possible solutions

Brain death has been accepted worldwide medically and legally as the biological state of death of the organism. Nevertheless, the literature has described persistent problems with this acceptance ever since brain death was described. Many of these problems are not widely known or properly understood by much of the medical community. Here we aim to clarify these issues, based on the two intractable problems in the brain death debates. First, the metaphysical problem: there is no reason that withstands critical scrutiny to believe that BD is the state of biological death of the human organism. Second, the epistemic problem: there is no way currently to diagnose the state of BD, the irreversible loss of all brain functions, using clinical tests and ancillary tests, given potential confounders to testing. We discuss these problems and their main objections and conclude that these problems are intractable in that there has been no acceptable solution offered other than bare assertions of an 'operational definition' of death. We present possible ways to move forward that accept both the metaphysical problem - that BD is not biological death of the human organism - and the epistemic problem - that as currently diagnosed, BD is a devastating neurological state where recovery of sentience is very unlikely, but not a confirmed state of irreversible loss of all [critical] brain functions. We argue that the best solution is to abandon the dead donor rule, thus allowing vital organ donation from patients currently diagnosed as BD, assuming appropriate changes are made to the consent process and to laws about killing.

The Last Breath: Historical Controversies Surrounding Determination of Cardiopulmonary Death

Cardiopulmonary determination of death is a mainstay of the practice of internal medicine and pulmonary physicians. Despite this, there is considerable variability in death exams. This article tracks the evolution of the tripartite death exam, initially developed in the middle of the nineteenth century to protect against premature burial. While the societal context for controversies about death determination has shifted to discussions about end-of-life care in intensive care units and organ transplantation, the cardiopulmonary death exam has largely remained unchanged from its original formulation. The recognition of coma dépassé and brain death has further pushed the focus of the death exam onto the neurological system. Despite advancing diagnostics and legislative attempts to standardize the definition of death, cardiopulmonary death determination largely remains an ad hoc process.

Brain death

Since the Harvard report of 1968, the concept of brain death has become widely recognized throughout the world. Most developed countries have accepted brain death as constituting death of the individual, and allow such patients to be used as ‘heart-beating’ organ donors. Although the US and most other countries accept a ‘whole-brain’ definition of brain death, the concept of brainstem death has been adopted in the UK. This article describes the UK diagnostic criteria in detail, and compares these with the criteria used in other countries. Management of the brain dead organ donor is described, and controversies relating to the concept of brain death are also discussed.

Radionuclide Evaluation of Brain Death in the Post-McMath Era

The pronouncement of death is a determination of paramount social, legal, and ethical import. The novel construct of "brain death" was introduced 50 years ago, yet there persist gaps in understanding regarding this diagnosis on the part of medical caregivers and families. The tragic, much-publicized case of Jahi McMath typifies potential problems that can be encountered with this diagnosis and serves as an effective point of departure for discussion. This article recapitulates the historical development of brain death and the evolution of scintigraphic examinations as ancillary or confirmatory studies, emphasizing updated clinical and imaging practice guidelines and the current role of scintigraphy. The limitations of clinical and radionuclide studies are then reviewed. Finally, the article examines whether radionuclide examinations might be able to play an expanded role in the determination of brain death by improving accuracy and facilitating effective communication with family members.

Determination of Death and the Dead Donor Rule: A Survey of the Current Law on Brain Death

Despite seeming uniformity in the law, end-of-life controversies have highlighted variations among state brain death laws and their interpretation by courts. This article provides a survey of the current legal landscape regarding brain death in the United States, for the purpose of assisting professionals who seek to formulate or assess proposals for changes in current law and hospital policy. As we note, the public is increasingly wary of the role of organ transplantation in determinations of death, and of the variability of brain death diagnosing criteria. We urge that any attempt to alter current state statutes or to adopt a national standard must balance the need for medical accuracy with sound ethical principles which reject the utilitarian use of human beings and are consistent with the dignity of the human person. Only in this way can public trust be rebuilt.

Brainstem death: A comprehensive review in Indian perspective

With the advent of cardiopulmonary resuscitation techniques, the cardiopulmonary definition of death lost its significance in favor of brain death. Brain death is a permanent cessation of all functions of the brain in which though individual organs may function but lack of integrating function of the brain, lack of respiratory drive, consciousness, and cognition confirms to the definition that death is an irreversible cessation of functioning of the organism as a whole. In spite of medical and legal acceptance globally, the concept of brain death and brain-stem death is still unclear to many. Brain death is not promptly declared due to lack of awareness and doubts about the legal procedure of certification. Many brain dead patients are kept on life supporting systems needlessly. In this comprehensive review, an attempt has been made to highlight the history and concept of brain death and brain-stem death; the anatomical and physiological basis of brain-stem death, and criteria to diagnose brain-stem death in India.

On noncongruence between the concept and determination of death

The debate about exactly when a person dies can benefit from distinguishing the strict biological concept of death from the medical standards for determining death.

Clinical review: the role of the intensivist and the rapid response team in nosocomial end-of-life care

In-hospital end-of-life care outside the ICU is a new and increasing aspect of practice for intensive care physicians in countries where rapid response teams have been introduced. As more of these patients die from withdrawal or withholding of artificial life support, determining whether a patient is dying or not has become as important to intensivists as the management of organ support therapy itself. Intensivists have now moved to making such decisions in hospital wards outside the boundaries of their usual closely monitored environment. This strategic change may cause concern to some intensivists; however, as custodians of the highest technology area in the hospital, intensivists are by necessity involved in such processes. Now, more than ever before, intensive care clinicians must consider the usefulness of key concepts surrounding nosocomial death and dying and the importance and value of making a formal diagnosis of dying in the wards. In this article, we assess the conceptual background, reference points, challenges and implications of these emerging aspects of intensive care medicine.

Controversies in defining and determining death in critical care

Circulatory-respiratory or brain tests are widely accepted for definition and determination of death, but have several controversial issues. Both determinations have been stimulated by organ donation, but must be valid independently of this process. Current controversies in brain death include whether the definition is conceptually coherent, whether the whole-brain or brainstem criterion is correct, whether one neurological examination or two should be required, and when to conduct the examination following therapeutic hypothermia. Controversies about the circulatory determination of death include the minimum duration of asystole that is sufficient for death to be declared, and whether the distinction between permanent and irreversible cessation of circulatory functioning is important. In addition, the goal of organ donation raises issues such as the optimal way to time and conduct the request conversation with family members of the patient, and whether the Dead Donor Rule should be abandoned.

The definition and criterion of death

The definition and criterion of death have been rendered ambiguous by developments in organ support technology, particularly the positive-pressure ventilator and vasopressor medications, that uncouple the unitary loss of vital functions in death and create cases in which the brain has been destroyed while circulation and ventilation can be supported. Developing a biophilosophic analysis of the meaning of death before physicians can declare it requires four sequential steps: (1) agreement on the paradigm conditions that frame the analysis and clarify the task; (2) identifying the definition of death, which makes explicit the meaning of death that is accepted in our consensual usage of the term but that has become obscured by technology; (3) identifying the criterion of death that shows that the definition has been fulfilled, and that can be incorporated into a death statute; and (4) devising bedside tests of death for physicians to perform to satisfy the criterion. Although there is a strong consensus on death determination medical standards in countries around the world that has been enshrined into laws, and accepted by most societies and religions, there remains an active dispute among scholars on the precise definition and criterion of death.

Diffuse Ischemia in Noncontrast Computed Tomography Predicts Outcome in Patients in Intensive Care Unit

Purpose

In the intensive care unit (ICU), prognosticating patients who are comatose or defining brain death can be challenging. Currently, the criteria for brain death are clinical supported by paraclinical tests. Noncontrast computed tomography (CT) shows diffuse loss of grey-white differentiation consistent with infarction. We hypothesize that the extent of hypodensity is predictive of poor neurologic outcome or brain death.

Materials and Methods

A total of 235 consecutive adult patients with cardiac arrest or with serious trauma admitted to ICU in 1 year were studied. Seventy met inclusion criteria. CT images were reviewed by multiple observers blinded to final outcome who assessed for loss of grey-white conspicuity. A modification of the validated Alberta Stroke Program Early CT Score (ASPECTS) was used to include non–middle cerebral artery territories. Primary outcome was death or functional disability at 3 months. Dichotomized CT scores were correlated with poor clinical status (Glasgow Coma Score < 5 and APACHE [Acute Physiology and Chronic Health Evaluation] score >19) and poor outcome (modified Rankin Scale >2).

Results

The CT score was ≤10 in 7 patients and >10 in 63 patients. The CT score value correlated with the severity of baseline clinical status on the Glasgow Coma Score ( r = 0.53, P < .01) and negatively with the APACHE-II score ( r = −0.27, P < .05). The CT score value negatively correlated with functional outcome ( r = −0.40, P < .01). All the patients with a CT score ≤10 died. The sensitivity of the CT score for functional outcome was 24%, and specificity was 100%. Agreement among observers for the CT score was good (Intraclass correlation coefficient = 0.77).

Conclusion

Diffuse loss of grey-white matter differentiation is subtle but specific for poor neurologic outcome, which may allow earlier prognostication of patients in whom clinical parameters are difficult to assess.

The circulatory-respiratory determination of death in organ donation

OBJECTIVE

Death statutes permit physicians to declare death on the basis of irreversible cessation of circulatory-respiratory or brain functions. The growing practice of organ donation after circulatory determination of death now requires physicians to exercise greater specificity in circulatory-respiratory death determination. We studied circulatory-respiratory death determination to clarify its concept, practice, and application to innovative circulatory determination of death protocols.

RESULTS

It is ethically and legally appropriate to procure organs when permanent cessation (will not return) of circulation and respiration has occurred but before irreversible cessation (cannot return) has occurred because permanent cessation: 1) is an established medical practice standard for determining death; 2) is the meaning of "irreversible" in the Uniform Determination of Death Act; and 3) does not violate the "Dead Donor Rule."

CONCLUSIONS

The use of unmodified extracorporeal membrane oxygenation in the circulatory determination of death donor after death is declared should be abandoned because, by restoring brain circulation, it retroactively negates the previous death determination. Modifications of extracorporeal membrane oxygenation that avoid this problem by excluding brain circulation are contrived, invasive, and, if used, should require consent of surrogates. Heart donation in circulatory determination of death is acceptable if proper standards are followed to declare donor death after establishing the permanent cessation of circulation. Pending additional data on "auto-resuscitation," we recommend that all circulatory determination of death programs should utilize the prevailing standard of 2 to 5 mins of demonstrated mechanical asystole before declaring death.

A review of the criteria used to assess insensibility and death in hunted whales compared to other species

This review addresses the diagnosis of insensibility and death in various species so as to evaluate the validity of the current criteria used to judge death in hunted whales by the International Whaling Commission (IWC). The only other species in which official criteria of death have been formulated is humans and these are controversial with the kernel of the debate being the definition of brain death. In slaughter animals, the moment of insensibility is regarded as the most important criterion and the issue has received scientific interest related to the pre-slaughter stunning. During hunting of terrestrial wildlife, the moment of death is usually regarded as the moment the animal falls and does not move. Based on the data presented in the present paper, it is concluded that when death in whales is solely determined on the basis of the IWC criteria, which in practice are based on immobility, a significant proportion of animals will be recorded as being sensible and alive when they are actually unconscious and the time to death (TTD) will be overestimated. If the criteria are used in conjunction with a postmortem examination, the recorded TTD will be closer to the real TTD and can be used for comparison of methods and performance.

Variability among hospital policies for determining brain death in adults*

OBJECTIVE

In the absence of federal requirements or state statutes, criteria to certify brain death are specified by medical staff and administrative policies in individual hospitals. Variability among such policies may allow inconsistency in the declaration of death by neurologic criteria. Our intent was to partially quantify diversity among hospital standards used in brain death certification.

DESIGN

Survey.

SETTING

Six hundred randomly selected hospitals.

PATIENTS

None.

INTERVENTIONS

A survey was conducted of 600 hospitals randomly selected from the American Hospital Association registry representing 200 hospitals each of <300 beds, 300-500 beds, and >500 beds. One hundred six policies submitted by these institutions comprised the final study group. Policies were reviewed for criteria of interest and were compared against variables recommended by the American Academy of Neurology.

MEASUREMENTS AND MAIN RESULTS

Significant variability in policy criteria was found compared with the American Academy of Neurology and other authoritative standards. Differences were greatest in specifying conditions to be excluded before testing and in specific testing methods during a detailed physical examination. The few differences noted between larger vs. smaller hospitals most likely reflect greater availability of resources in larger institutions.

CONCLUSIONS

Differences among hospital policies for certification of brain death may permit variability among hospitals throughout the United States in the pronouncement of death by neurologic criteria. Standardization and enforcement of policies that ensure the highest possible accuracy should be considered.

Medical and legal considerations of brain death

Brain death was first defined in 1968, and since then laws on determining death have been implemented in all countries with active organ transplantation programs. As a prerequisite, the aetiology of brain death has to be known, and all reversible causes of coma have to be excluded. The regulations for the diagnosis of brain death are most commonly given by the national medical associations, and they vary between countries. Thus, the guidelines given in the medical textbooks are not universally applicable. The diagnosis is based on clinical examination, but confirmatory tests, such as angiography or EEG, are allowed on most occasions. Brain death is followed by cardiovascular and hormonal changes, which have implications in the management of a potential organ donor. Spinal reflexes are preserved, and motor and haemodynamic responses are frequently observed in brain dead patients.

Brain death: resolving inconsistencies in the ethical declaration of death

PURPOSE

The first criteria for the determination of brain death were developed in 1968 in part to address concerns that had arisen with the retrieval of organs for transplantation. Despite over 30 years of application, some professional and public doubt persists over the validity of the theoretical construct underlying this method of determining death. Our review will address historical perspectives on the development of brain death criteria, and inconsistencies in current clinical criteria.

METHOD

Narrative review from selected MEDLINE references and other published sources.

PRINCIPLE FINDINGS

The primary construct of the determination of death is that either cardiopulmonary or neurological function irreversibly ceases. However, there is inconsistency in the neurological criteria for death between jurisdictions, between patient populations, and in the use of confirmatory tests. These inconsistencies may cause concern in the public or profession about the validity of the determination of death by neurological criteria.

CONCLUSIONS

Organ transplantation is premised on professional and public acceptance that the donor is dead. Given that the criteria for brain death or their application remain variable, we suggest that it is reasonable to consider a national consensus to address these inconsistencies. Alternatively, the standard use of confirmatory radiographic testing prior to the retrieval of organs from donors who meet clinical brain death criteria should be considered to provide conclusive evidence of permanent and irreversible loss of brain function.

Some politico-economic aspects of organ shortage in transplantation medicine

Transplantation of solid organs has become a widely performed and accepted procedure. This type of high-performance medicine has led to vigorous debates on ethical and economic issues and most of this discussion can be seen as an example of the different opinions about highly individualised and technologised approaches in health care. The paper focuses on the rising gap in the demand for suitable organs for transplantation and the levelling off, or even fall, in the supply of these organs. Despite the rather demanding requirements for organ donation, there appear to be a sufficient number of deaths under suitable circumstances to satisfy the annual demand of transplantable organs--if the collection rates are adequate. It has been shown that there are great differences in the rate of organ procurement efficiency within different regions. The question then is how to set appropriate incentives to obtain organs in sufficient quantities from eligible donors to meet the demand. This paper discusses the different medical and societal approaches as well as the economic proposals to overcome the organ shortage. The theory of Public Choice is used to develop a specific policy that can be applied to organ procurement efforts. This is a different approach, whereby political and economic considerations of ethical dilemmas focus on setting appropriate and widely accepted frameworks and rules, in which individuals may then decide about their behaviour. In an appendix, the economic consequences of transplantation medicine are discussed if more organs were to be made available and the impacts of relaxing the simplifying assumptions on effectiveness of organ replacement therapy and on the allocation system are considered. Ultimately, artificial organs or genetically transformed animal organs may be used but it is highly likely that a vigorous debate on the ethics and especially financial implications of these interventions will take place beforehand.