A survey to determine the understanding of the conceptual basis and diagnostic tests used for brain death by neurosurgeons in Canada

The Fundamental Concept of Death-Controversies and Clinical Relevance: The UDDA Revision Series

When the Uniform Law Commission (ULC) was recently in the process of revising the Uniform Determination of Death Act (UDDA), Neurology® ran a series of debates over certain controversial issues being deliberated. Omitted was a debate over the fundamental concept underlying brain death. In his introductory article, Bernat offered reasons for this omission: "It is not directly relevant to practicing neurologists who largely accept brain death, do not question its conceptual basis, …." In this article I argue the opposite: the fundamental concept of death is highly relevant to the clinical criteria and tests used to diagnose it. Moreover, most neurologists in fact disagree with the conceptual basis articulated by Bernat. Basically, there are 3 competing concepts of death: (1) biological: cessation of the integrative unity of the organism as a whole (endorsed by Bernat and the 1981 President's Commission), (2) psychological: cessation of the person, equated with a self-conscious mind (endorsed by half of neurologists), and (3) the vital work concept proposed by the 2008 President's Council on Bioethics. The first actually corresponds to a circulatory, not a neurologic, criterion. The second corresponds to a "higher brain" criterion. The third corresponds loosely to the UK's "brainstem death" criterion. In terms of the biological concept, current diagnostic guidelines entail a high rate of false-positive declarations of death, whereas in terms of the psychological concept, the same guidelines entail a high rate of false-negative declarations. Brainstem reflexes have nothing to do with any death concept (their role is putatively to guarantee irreversibility). By shining a spotlight on the deficiencies of the UDDA through attempting to revise it, the ULC may have unwittingly opened a Pandora's box of fresh scrutiny of the concept of death underlying the neurologic criterion-particularly on the part of state legislatures with irreconcilably opposed worldviews.

Rationale for revisions to the definition of death and criteria for its determination in Canada

Clarity regarding the biomedical definition of death and the criteria for its determination is critical to inform practices in clinical care, medical research, law, and organ donation. While best practices for death determination by neurologic criteria and circulatory criteria were previously outlined in Canadian medical guidelines, several issues have arisen to force their reappraisal. Ongoing scientific discovery, corresponding changes in medical practice, and legal and ethical challenges compel a comprehensive update. Accordingly, the A Brain-Based Definition of Death and Criteria for its Determination After Arrest of Neurologic or Circulatory Function in Canada project was undertaken to a develop a unified brain-based definition of death, and to establish criteria for its determination after devastating brain injury and/or circulatory arrest. Specifically, the project had three objectives: (1) to clarify that death is defined in terms of brain functions; (2) to clarify how a brain-based definition of death is articulated; and (3) to clarify the criteria for determining if the brain-based definition is met. The updated death determination guideline therefore defines death as the permanent cessation of brain function and describes corresponding circulatory and neurologic criteria to ascertain the permanent cessation of brain function. This article explores the challenges that prompted revisions to the biomedical definition of death and the criteria for its determination and outlines the rationales underpinning the project's three objectives. By clarifying that all death is defined in terms of brain function, the project seeks to align guidelines with contemporary medicolegal understandings of the biological basis of death.

The Understanding of Human Death by Polish Early Career Pre-Specialist Physicians

Despite the legal classification of cerebral death as the actual death of a human being and the continuous clarification of neurological criteria, the subject of death, particularly, when exactly it occurs, has been the subject of debate not only in the medical environment but also in other scientific communities for over sixty years. This issue is also present in social discourse. In Poland, as well as in other countries, the concepts of "death" and "cerebral death" have a legal basis. Considerations devoted to death are also important for tanatopedagogics, which focuses primarily on mortality. Indeed, the quality of relationships with other people depends to a large extent on the awareness of death. The study involved 113 pre-specialist physicians employed in various medical centers in Poland. An original questionnaire was used to study the understanding of human death in the light of legal and medical acts that came into force between 2007 and 2019. The study showed that only 7.08% of pre-specialist physicians could fully and correctly identify the basis for declaring a patient dead after diagnosing the irreversible cessation of brain function, and only 33.63% of all respondents understood death in accordance with legal acts currently in force in Poland. Moreover, nearly half of the study participants (47.79%) indicated that irreversible loss of consciousness is not adequate grounds for determining a patient's death, while 56.64% felt that cerebral death is equal to the biological death of a human being. Women were significantly more likely to understand the concept of death (p = 0.028) as defined by current documents and to perceive the irreversible loss of consciousness as an insufficient basis for determining a patient's death (p = 0.040) and also to correctly indicate on what basis cerebral death is identified with human death (p = 0.003), as expressed by current legal regulations in Poland.

Healthcare Professionals’ Understandings of the Definition and Determination of Death: A Scoping Review

Background.

During the 1950s, advances in critical care, and organ transplantation altered the relationship between organ failure and death. There has since been a shift away from traditional cardiocirculatory based to brain-based criteria of death, with resulting academic controversy, despite the practice being largely accepted worldwide. Our objective is to develop a comprehensive description of the current understandings of healthcare professionals regarding the meaning, definition, and determination of death.

Methods.

Online databases were used to identify papers published from 2003 to 2020. Additional sources were searched for conference proceedings and theses. Two reviewers screened papers using predefined inclusion and exclusion criteria. Complementary searches and review of reference lists complemented the final study selection. A data extraction instrument was developed to iteratively chart the results of the review. A qualitative approach was conducted to thematically analyze the data.

Results.

Seven thousand four hundred twenty-eight references were identified. In total, 75 papers met the inclusion criteria. Fourteen additional papers were added from complementary searches. Most were narratives (35%), quantitative investigations (21%), and reviews (18%). Identified themes included: (1) the historical evolution of brain death (BD), (2) persistent controversies about BD and death determination, (3) wide variability in healthcare professionals’ knowledge and attitudes, (4) critical need for BD determination revision.

Conclusions.

We concluded that although BD is widely accepted, there exists variation in healthcare providers’ understanding of its conceptual basis. Death determination remains a divisive issue among scholars. This review identified a need for increased opportunities for formal training on BD among healthcare providers.

Brain death debates: from bioethics to epistemology

50 years after its introduction, brain death remains controversial among scholars. The debates focus on one question: is brain death a good criterion for determining death? This question has been answered from various perspectives: medical, metaphysical, ethical, and legal or political. Most authors either defend the criterion as it is, propose some minor or major revisions, or advocate abandoning it and finding better solutions to the problems that brain death was intended to solve when it was introduced. In short, debates about brain death have been characterized by partisanship, for or against. Here I plead for a non-partisan approach that has been overlooked in the literature: the epistemological or philosophy of science approach. Some scholars claim that human death is a matter of fact, a biological phenomenon whose occurrence can be determined empirically, based on science. We should take this claim seriously, whether we agree with it or not. The question is: how do we know that human death is a scientific matter of fact? Taking the epistemological approach means, among other things, examining how the determination of human death became an object of scientific inquiry, exploring the nature of the brain death criterion itself, and analysing the meaning of its core concepts such as "irreversibility" and "functions".

Brain death debates: from bioethics to philosophy of science

50 years after its introduction, brain death remains controversial among scholars. The debates focus on one question: is brain death a good criterion for determining death? This question has been answered from various perspectives: medical, metaphysical, ethical, and legal or political. Most authors either defend the criterion as it is, propose some minor or major revisions, or advocate abandoning it and finding better solutions to the problems that brain death was intended to solve when it was introduced. Here I plead for a different approach that has been overlooked in the literature: the philosophy of science approach. Some scholars claim that human death is a matter of fact, a biological phenomenon whose occurrence can be determined empirically, based on science. We should take this claim seriously, whether we agree with it or not. The question is: how do we know that human death is a scientific matter of fact? Taking the philosophy of science approach means, among other things, examining how the determination of human death became an object of scientific inquiry, exploring the nature of the brain death criterion itself, and analysing the meaning of its core concepts such as "irreversibility" and "functions".

Building a Fence Around Brain Death: The Shielded-Brain Formulation

The concept of brain death was proposed more than 50 years ago, and it has been incorporated in laws and clinical practice, but it remains a source of confusion, debate, and litigation. Because of persistent variability in clinical standards and ongoing controversies regarding policies, the Uniform Law Commission, which drafted the Uniform Determination of Death Act in 1980, has appointed a committee to study whether the act should be revised. This article reviews the history of the concept of brain death and its philosophical underpinnings, summarizes the objections that have been raised to the prevailing philosophical formulations, and proposes a new formulation that addresses those objections while preserving current practices.

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.

A Framework for Revisiting Brain Death: Evaluating Awareness and Attitudes Toward the Neuroscientific and Ethical Debate Around the American Academy of Neurology Brain Death Criteria

BACKGROUND

There remains a lack of awareness around the American Academy of Neurology (AAN) procedural criteria for brain death and the surrounding controversies, leading to significant practice variability. This survey study assessed for existing knowledge and attitude among healthcare professionals regarding procedural criteria and potential change after an educational intervention.

METHODS

Healthcare professionals with increased exposure to brain injury at Mayo Clinic hospitals in Arizona and Florida were invited to complete an online survey consisting of 2 iterations of a 14-item questionnaire, taken before and after a 30-minute video educational intervention. The questionnaire gathered participants' opinion of (1) their knowledge of the AAN procedural criteria, (2) whether these criteria determine complete, irreversible cessation of brain function, and (3) on what concept of death they base the equivalence of brain death to biological death.

RESULTS

Of the 928 people contacted, a total of 118 and 62 participants completed the pre-intervention and post-intervention questionnaire, respectively. The results show broad, unchanging support for the concept of brain death (86.8%) and that current criteria constitute best practice. While 64.9% agree further that the loss of consciousness and spontaneous breathing is sufficient for death, contradictorily, 37.6% believe the loss of additional integrated bodily functions such as fighting infection is necessary for death. A plurality trusts these criteria to demonstrate loss of brain function that is irreversible (67.6%) and complete (43.6%) at baseline, but there is significantly less agreement on both at post-intervention.

CONCLUSION

Although there is consistent support that AAN procedural criteria are best for clinical practice, results show a tenuous belief that these criteria determine irreversible and complete loss of all brain function. Despite support for the concept of brain death first developed by the President's Council, participants demonstrate confusion over whether the loss of consciousness and spontaneous breath are truly sufficient for death.

Statement in Support of Revising the Uniform Determination of Death Act and in Opposition to a Proposed Revision

Discrepancies between the Uniform Determination of Death Act (UDDA) and the adult and pediatric diagnostic guidelines for brain death (BD) (the "Guidelines") have motivated proposals to revise the UDDA. A revision proposed by Lewis, Bonnie and Pope (the RUDDA), has received particular attention, the three novelties of which would be: (1) to specify the Guidelines as the legally recognized "medical standard," (2) to exclude hypothalamic function from the category of "brain function," and (3) to authorize physicians to conduct an apnea test without consent and even over a proxy's objection. One hundred seven experts in medicine, bioethics, philosophy, and law, spanning a wide variety of perspectives, have come together in agreement that while the UDDA needs revision, the RUDDA is not the way to do it. Specifically, (1) the Guidelines have a non-negligible risk of false-positive error, (2) hypothalamic function is more relevant to the organism as a whole than any brainstem reflex, and (3) the apnea test carries a risk of precipitating BD in a non-BD patient, provides no benefit to the patient, does not reliably accomplish its intended purpose, and is not even absolutely necessary for diagnosing BD according to the internal logic of the Guidelines; it should at the very least require informed consent, as do many procedures that are much more beneficial and less risky. Finally, objections to a neurologic criterion of death are not based only on religious belief or ignorance. People have a right to not have a concept of death that experts vigorously debate imposed upon them against their judgment and conscience; any revision of the UDDA should therefore contain an opt-out clause for those who accept only a circulatory-respiratory criterion.

Requests for somatic support after neurologic death determination: Canadian physician experiences

PURPOSE

Neurologic determination of death (NDD) is legally accepted as death in Canada but remains susceptible to misunderstandings. In some cases, families request continued organ support after NDD. Conflicts can escalate to formal legal challenges, causing emotional, financial, and moral distress for all involved. We describe prevalence, characteristics, and common experiences with requests for continued organ support following NDD in Canada.

METHODS

Mixed-methods design combining anonymous online survey with semi-structured interviews of Canadian critical care physicians (448 practitioners, adult and pediatric).

RESULTS

One hundred and six physicians responded to the survey and 12 participated in an interview. Fifty-two percent (55/106) of respondents had encountered a request for continued organ support after NDD within two years, 47% (26/55) of which involved threat of legal action. Requests for continued support following NDD ranged from appeals for time for family to gather before ventilator removal to disagreement with the concept of NDD. Common responses to requests included: consultation with an additional physician (54%), consultation with spiritual services (41%), and delay of one to three days for NDD acceptance (49%). Respondents with prior experience were less likely to recommend ancillary tests (P = 0.004) or consultation with bioethics services (P = 0.004). Qualitative analysis revealed perceptions that requests for continued organ support were driven by mistrust, tensions surrounding decision-making, and cultural differences rather than a lack of specific information about NDD.

CONCLUSIONS

Family requests for continued somatic support following NDD were encountered by half our sample of Canadian critical care physicians. Mitigation strategies require attention to the multifaceted social contexts surrounding these complex scenarios.

Do the 'brain dead' merely appear to be alive?

The established view regarding 'brain death' in medicine and medical ethics is that patients determined to be dead by neurological criteria are dead in terms of a biological conception of death, not a philosophical conception of personhood, a social construction or a legal fiction. Although such individuals show apparent signs of being alive, in reality they are (biologically) dead, though this reality is masked by the intervention of medical technology. In this article, we argue that an appeal to the distinction between appearance and reality fails in defending the view that the 'brain dead' are dead. Specifically, this view relies on an inaccurate and overly simplistic account of the role of medical technology in the physiology of a 'brain dead' patient. We conclude by offering an explanation of why the conventional view on 'brain death', though mistaken, continues to be endorsed in light of its connection to organ transplantation and the dead donor rule.

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.

Renaissance of criticism on the concept of brain death--the role of legal medicine in the context of the interdisciplinary discussion

BACKGROUND

In the practice of legal medicine in Germany, the assessment of brain death is of minor importance and attracts little attention. However, since several years, international criticism on the concept of brain death has culminated. By reviewing literature and the results of a questionnaire distributed among the participants of the 93rd Annual Congress of the Germany Society of Legal Medicine, the state of knowledge and the current views on brain death were evaluated.

MATERIALS AND METHODS

Literature search of recent publications regarding brain death was performed (PubMed database, references of legal medicine, Report of the President's Council on Bioethics, USA 2008). A questionnaire was developed and distributed among the participants of the Congress.

RESULTS

The assumption that individual and brain death are synonymous is criticized. Internationally, there are trends to harmonize the very different clinical criteria to assess brain death. The diagnostic advantage of novel techniques such as CT angiography is controversially discussed. It becomes apparent that procedures which record the blood flow and perfusion of the brain will be applied more in the future. Regrettably, these developments are not described in the literature of legal medicine. Moreover, among German forensic scientists, different views concerning brain death exist. The majority favors its equivalent treatment with individual death. The thanatological background can be improved concerning certain aspects of brain death as well as its legal implications.

CONCLUSION

Teaching and research in legal medicine should include the subject brain death. Expertise in forensic science may contribute to the interdisciplinary discussion on brain death. The transfer of actual knowledge, also on disputed ethical aspects of thanatology, to physicians of all disciplines is of great importance.

Practice variability in brain death determination: a call to action

OBJECTIVE

To characterize the present state of brain death (BD) determination in actual practice relative to contemporary American Academy of Neurology (AAN) guidelines.

METHODS

We reviewed the charts of all adult (16 years and older) BD organ donors during 2011 from 68 heterogeneous hospitals in the Midwest United States. Data were collected across 5 categories: guideline performance, preclinical testing, clinical examination, apnea testing, and use of ancillary tests. Practice within categories and overall adherence to AAN guidelines were assessed.

RESULTS

Two hundred twenty-six BD organ donors were included. Practice exceeded recommendations in guideline performance but varied widely and deviated from AAN guidelines in all other categories. One hundred two (45.1%) had complete documentation of brainstem areflexia and absent motor response. One hundred sixty-six (73.5%) had completed apnea testing. Of the 60 without completed apnea testing, 56 (93.3%) had ancillary tests consistent with BD. Overall, 101 (44.7%) strictly and 84 (37.2%) loosely adhered to contemporary AAN guidelines.

CONCLUSIONS

There is wide variability in the documentation of BD determination, likely reflecting similar variability in practice. This is a call for improved documentation, better uniformity of policies, and comprehensive and strategically targeted educational initiatives to ensure consistently contemporary approaches to BD determination in every patient.

A survey of American neurologists about brain death: understanding the conceptual basis and diagnostic tests for brain death

Background

Neurologists often diagnose brain death (BD) and explain BD to families in the intensive care unit. This study was designed to determine whether neurologists agree with the standard concept of death (irreversible loss of integrative unity of the organism) and understand the state of the brain when BD is diagnosed.

Methods

A previously validated survey was mailed to a random sample of 500 board-certified neurologists in the United States. Main outcomes were: responses indicating the concept of death that BD fulfills and the empirical state of the brain that would rule out BD.

Results

After the second mailing, 218 (44%) surveys were returned. Few (n = 52, 27%; 95% confidence interval (CI), 21%, 34%) responded that BD is death because the organism has lost integrative unity. The most common justification was a higher brain concept (n = 93, 48%; 95% CI, 41%, 55%), suggesting that irreversible loss of consciousness is death. Contrary to the recent President's Council on Bioethics, few (n = 22, 12%; 95% CI, 8%, 17%) responded that the irreversible lack of vital work of an organism is a concept of death that the BD criterion may satisfy. Many responded that certain brain functions remaining are not compatible with a diagnosis of BD, including EEG activity, evoked potential activity, and hypothalamic neuroendocrine function. Many also responded that brain blood flow and lack of brainstem destruction are not compatible with a diagnosis of BD.

Conclusions

American neurologists do not have a consistent rationale for accepting BD as death, nor a clear understanding of diagnostic tests for BD.

The bispectral index, a useful adjunct for the timely diagnosis of brain death in the comatose trauma patient

BACKGROUND

The bispectral index (BIS) is a processed electroencephalographic value (awake = 100, isoelectric = 0). The relationship of BIS and brain death (BD) is assessed.

METHODS

BIS was evaluated in GCS 3 head-injured patients with BD (no brain function including apnea) or near BD (no apnea or negative ancillary test [cerebral perfusion and electroencephalogram]).

RESULTS

In 27 patients, there were 37 BD evaluations (apnea assessment or ancillary test). BD was confirmed in 62% (n = 23). However, 38% (n = 14) showed near BD. BD BIS is 3 + or - 5 and near BD BIS is 36 + or - 31 (P = .002). In the 23 BD patients, BIS was <20 for 7 hours + or - 6 hours before a BD evaluation was performed. Of 14 near BD evaluations, 9 (64%) had BIS > or = 20. BIS <20 for predicting BD had a sensitivity of 100% (23/23), a positive predictive value of 84% (23/28), and a negative predictive value of 100% (9/9).

CONCLUSIONS

Distinguishing brain death and near brain death in severely comatose trauma patients is complex. By indicating the likelihood of brain death, BIS is an adjunct for efficient evaluation.

A 10-month-old infant with reversible findings of brain death

Death has occurred when there is irreversible loss of integration of the organism as a whole, and brain death is said to be a criterion for death. In the present case, a 10-month-old boy was found submerged in a bathtub and was given cardiopulmonary resuscitation for 37 minutes. He had received therapeutic dosing of phenobarbital and midazolam up to 5 hours prior to a brain death examination. He fulfilled all criteria for brain death according to Canadian Neurological Determination of Death Forum recommendations on an examination 42 hours after the drowning event, but started breathing another 15 hours later. Eleven previously published cases of purported reversal of findings of brain death are discussed here, including two infants who fulfilled all criteria for brain death for more than 24 hours. Recommendations for brain death determination may require revision for infants, to more clearly define a time interval between examinations and to incorporate consideration of confounding sedative drug effects. Together with previous reports, the present case calls into question the assumption that brain death as currently diagnosed is irreversible, and therefore equivalent to death of the patient.

Brain death, states of impaired consciousness, and physician-assisted death for end-of-life organ donation and transplantation

In 1968, the Harvard criteria equated irreversible coma and apnea (i.e., brain death) with human death and later, the Uniform Determination of Death Act was enacted permitting organ procurement from heart-beating donors. Since then, clinical studies have defined a spectrum of states of impaired consciousness in human beings: coma, akinetic mutism (locked-in syndrome), minimally conscious state, vegetative state and brain death. In this article, we argue against the validity of the Harvard criteria for equating brain death with human death. (1) Brain death does not disrupt somatic integrative unity and coordinated biological functioning of a living organism. (2) Neurological criteria of human death fail to determine the precise moment of an organism's death when death is established by circulatory criterion in other states of impaired consciousness for organ procurement with non-heart-beating donation protocols. The criterion of circulatory arrest 75 s to 5 min is too short for irreversible cessation of whole brain functions and respiration controlled by the brain stem. (3) Brain-based criteria for determining death with a beating heart exclude relevant anthropologic, psychosocial, cultural, and religious aspects of death and dying in society. (4) Clinical guidelines for determining brain death are not consistently validated by the presence of irreversible brain stem ischemic injury or necrosis on autopsy; therefore, they do not completely exclude reversible loss of integrated neurological functions in donors. The questionable reliability and varying compliance with these guidelines among institutions amplify the risk of determining reversible states of impaired consciousness as irreversible brain death. (5) The scientific uncertainty of defining and determining states of impaired consciousness including brain death have been neither disclosed to the general public nor broadly debated by the medical community or by legal and religious scholars. Heart-beating or non-heart-beating organ procurement from patients with impaired consciousness is de facto a concealed practice of physician-assisted death, and therefore, violates both criminal law and the central tenet of medicine not to do harm to patients. Society must decide if physician-assisted death is permissible and desirable to resolve the conflict about procuring organs from patients with impaired consciousness within the context of the perceived need to enhance the supply of transplantable organs.