Since a groundbreaking 1968 report, vigorous debate has ensued regarding how we ought to conceptually define and clinically determine when a human being has died. At the conceptual level, debate centers upon whether a human being qua “person”—understood in a Lockean psychological sense—dies if they become irreversibly comatose or if a human being is essentially an organism whose death should be defined in strictly biological terms. The latter concept has informed legal statutes, such as the U.S. Uniform Determination of Death Act (UDDA), which allows for death to be declared if a human being has experienced irreversible cessation of either “circulatory and respiratory functions” or “all functions of the entire brain, including the brain stem.” The latter “neurological criterion” comprises irreversible loss of not only consciousness but also a human organism’s capacity to sustain itself through the circulation of oxygenated blood insofar as the brain stem is required for spontaneous respiration.
Challenges to the neurological criterion have been based on a number of cases, including the highly-publicized cases of Jahi McMath and Marlise Munoz, involving long-term somatic survival following neurological determination of death. While such neurologically devastated bodies require biotechnological support mechanisms such as ventilation and tube-feeding, they continue to maintain homeostasis, proportionally grow, fight off infections, go through puberty (in McMath’s case), and can even gestate a fetus (in Munoz’s case); it is difficult to claim that such bodies are not living organisms.
Even among defenders of the neurological criterion, there are points of contention, such as whether persistent hypothalamic function—present in about half the cases of patients declared dead by the neurological criterion—is consistent with the organismic concept of death. While this debate may appear to be a matter of physiology, it is fundamentally a matter of biophilosophy. Both defenders of the current neurological criterion and critics who argue that the neurological criterion should include the death of the whole brain, including the hypothalamus, invoke distinct conceptual understandings of what it means to be a self-sustaining human organism, appealing to distinctions between, for instance, the mere “coordination” of the body’s various parts versus the “integration” of the body’s heterogenous parts into an organism as a whole.
The alternative “circulatory criterion” for determining death also has been a catalyst for philosophical debate, centering on the UDDA’s requirement that loss of spontaneous circulatory function be “irreversible.” In various protocols that have been developed by hospitals to allow for vital organ retrieval following circulatory determination of death, a “hands-off” period of as little as two minutes following heartbeat cessation is required before organ retrieval may proceed. This waiting period is purported to respect the “dead donor rule,” which requires that organ retrieval must not cause the patient’s death and can only occur once the patient has been legally declared dead. Critics of such organ retrieval protocols contend that two minutes—or five or eight minutes in more conservative protocols—is insufficient to ensure that spontaneous circulation cannot resume, and thus, the irreversibility requirement has not been met. Although it would be quite rare for spontaneous circulation to resume without any resuscitative efforts, for many patients, if cardiopulmonary resuscitation measures were employed during the waiting period, spontaneous circulation could potentially resume. This potentiality evinces that the cessation of the patient’s circulatory function is not, in fact, irreversible; rather, the resumption of circulatory function is prevented by the physician’s decision—typically based on sound ethical reasons—not to employ resuscitative measures.
The practice of donation after circulatory determination of death has led to recent calls to revise the UDDA to stipulate a requirement of “permanent” cessation of circulation following a decision to remove artificial means of life-support and not to employ resuscitative measures once the patient’s circulatory function ceases. Although the U.S. Uniform Law Commission has to-date elected not to revise the UDDA in this way, it is nevertheless a widespread practice to treat the permanent (by fiat) cessation of circulatory function as equivalent to such function being irreversible. Some philosophers have thus argued that we should reconstrue death not as a biological event determinable as an objective fact but rather as a complex constructed concept that involves not only biological realities but also social conventions regarding when it is appropriate to treat someone as dead.
I have argued, from the anthropological perspective of Aristotelian-Thomism, that the death of a human organism is not a process but an event with a determinate moment involving a substantial change from a living being to a corpse, such change perhaps being masked by technological artifice. Determining when this moment occurs in a specific case, however, may not be epistemically feasible, and hence, we must rely on criteria—neurological or circulatory—that allow us to affirm that, at some past moment, a human being has died. Implicit in this view is a rejection of a psychologically-based notion that ontologically separates the death of a human person from that of a human organism; the Aristotelian-Thomistic view having affinities with animalism. I have also argued that a human being’s death is best understood in terms of the irreversible loss of neurological function—including both the cerebral cortex and the brainstem but excluding the hypothalamus—with the circulatory criterion being valid to declare death so long as there is a sufficient waiting period to reasonably ensure the irreversible cessation of neurological function due to anoxia. Most recently, I have argued against the relatively novel practice of normothermic regional perfusion, in which the body of a patient declared dead using the circulatory criterion is infused with oxygenated blood using “extracorporeal membrane oxygenation” (ECMO). What is ethically problematic about the use of ECMO in this way is that the arteries providing blood flow to the brain are clamped to ensure that neurological function will not resume. The evident intentionality underlying this practice is to violate the dead donor rule by bringing about the cessation of neurological function, implicitly understood to constitute the true death of a human organism.
As can be seen, there are myriad philosophical questions—metaphysical, ethical, epistemic, and sociopolitical—regarding how we conceptually understand and clinically determine when a human being has died. At the most fundamental level, philosophers must continue to debate the following questions: 1) Is death a concept that properly applies to human persons—understood psychologically—or to human organisms? 2) Is death a dynamic process or a determinate event? 3) Is death a metaphysically informed biological fact or a biologically informed social construct? 4) Does a proper biophilosophical understanding of the human organism support a neurological and/or circulatory criterion for determining death?
Considering that none of these questions are likely to yield consensus answers, another key question is what policies and clinical practices we ought to adopt in the context of uncertainty. As Aristotle noted, moral science can only provide the degree of certainty its subject matter allows. Hence, we cannot expect the same degree of certainty in our moral reasoning as we can in other areas of inquiry, such as logic or mathematics. We must thus reason toward prudential certitude—in other words, we must aim toward as much certainty as can be reasonably had that we are acting morally. But what are the criteria for claiming prudential certitude in ethical matters such as when we can explant vital organs from putatively dead human beings? In the face of reasonable doubt, should we err on the side of caution and not risk causing death because we have utilized the wrong criterion? Or, should we balance such risk with the potential benefits to those whose lives may be prolonged through organ transplantation? Two opposing responses, neither of which I endorse, are either to await the onset of putrefaction as the sure sign that death has occurred, precluding any possibility of organ transplantation, or, in order to respect autonomy and diverse cultural and religious perspectives, to abandon the dead donor rule and allow individuals (or their families) to decide for themselves which criterion, or even concept, of death ought to be employed in each case.
Jason T. Eberl
Jason T. Eberl is the Hubert Mäder Chair, Professor of Health Care Ethics and Philosophy, and Director of the Gnaegi Center for Health Care Ethics at Saint Louis University. His research interests include philosophical anthropology, biotechnology, and Thomism. His latest book is The Nature of Human Persons: Metaphysics and Bioethics.
