In the late twentieth century, as a response to certain advances in critical care medicine, a new standard for determining death became accepted in both the medical and legal communities in the United States and many other parts of the world. Until then, the prevailing standard was the traditional cardiopulmonary standard: the irreversible loss of heart and lung functions signals the death of a human being. The new standard, which took its place alongside the traditional one, is based on the irreversible loss of all brain-dependent functions. In most human deaths, the loss of these neurological functions is accompanied by the traditional, familiar markers of death: the patient stops breathing, his or her heart stops beating, and the body starts to decay. In relatively rare cases, however, the irreversible loss of brain-dependent functions occurs while the body, with technological assistance, continues to circulate blood and to show other signs of life. In such cases, there is controversy and confusion about whether death has actually occurred.
There is controversy as well about the use of the traditional cardiopulmonary standard in the organ procurement practice known as “controlled donation after cardiac death” (controlled DCD). Here, too, there is debate about whether, at the time that organs are taken, the donor is truly dead. But, with controlled DCD, there is also a more acute danger that the quality of end-of-life care for the patient-donor will be compromised.
The controversies surrounding both the neurological standard and controlled DCD are the subject of this report, although the report's primary focus is the resurgent debate about the ethical validity of the neurological standard. Forty years after its inception, long-standing doubts about the standard's biological basis, fueled by more recent clinical observations about patients diagnosed as “brain dead,” have reignited the debate about the standard's validity.
It was a key advance in medical technology—the mechanical ventilator—that originally gave rise to the confusions and controversies about when death occurs in a critical care setting. A review of the history of the neurological standard for death will help to explain why.
A. The Ventilator and the Problem of Determining Death
The mechanical ventilator externally supports the patient's breathing when injury or infirmity prevents the body from doing this vital work on its own. The injuries and diseases that might lead to a need for such support are many and varied. The incapacity to breathe on one's own is a common endpoint of different ailments and, of course, a terminal one unless help can be provided quickly. Although it does not treat the underlying disease, the ventilator may stave off death, often for months or even years.
Soon after the ventilator began to be used in hospitals all over the world, a set of ethical and philosophical complexities became evident. One involved the question of whether maintaining a patient on a ventilator is always in the best interest of the patient. In many cases in which a patient has suffered a devastating injury that leaves him or her unable to breathe spontaneously (that is, without external assistance), there is little chance that use of a ventilator will lead to much improvement in the patient's condition. The reason for this is that an inability to breathe spontaneously is often the result of a very serious injury to the brain. Saving a patient from death after such an injury turns out, in many cases, to be an ambiguous sort of success. This ambiguity often leads physicians and patients' loved ones to decide that death should be allowed to come even when the ventilator is capable of putting it off for a time. 1
B. "Coma Dépassé”—Beyond Coma
With the introduction of the ventilator, however, a different sort of problem emerged as well. Some brain-injured patients, dependent on the ventilator to breathe, turn out to be definitively more incapacitated than others who at first seem to be in a similar state. In 1959, French neurologists Pierre Mollaret and Maurice Goullon characterized this condition of maximal incapacitation. The label they provided for it was coma dépassé , or “beyond coma.” 2
At the same time, other physicians were discovering the same clinical facts about some of their own patients. In response, many medical experts concluded that what the ventilator accomplishes in these cases is very different from what it accomplishes in cases in which the patient is less incapacitated. In their judgment, a patient who is “beyond coma” is not being kept barely alive by the machine but, rather, is already dead . The machine is, in essence, ventilating a corpse—albeit one that in many ways does not look like a corpse. Today, other terms are used in place of coma dépassé , including the confusing and misleading term “brain death.” The question of terminology will be explored more fully in Chapter Two.
Those who understood the coma dépassé condition in this way distinguished, therefore, two groups of brain-injured, ventilator-dependent individuals. Members of one group of patients are already dead and should therefore be removed from the ventilator. The apparent signs of life that remain—a beating heart, warm skin, and minimal, if any, signs of bodily decay—are a sort of mask that hides from plain sight the fact that the biological organism has ceased to function as such. Members of the other group of patients are not already dead. For them—but not for the first group—an ethical dilemma arises as to whether further medical treatment is futile and should be discontinued, thus allowing them to die.
C. The Harvard Committee and the President's Commission
The point of view that accepts this distinction has become the dominant one in most parts of the world, including the United States. In 1968, a physician-led committee at Harvard Medical School , in an influential paper entitled “A Definition of Irreversible Coma,” concluded that patients who meet the diagnostic criteria for a certain type of severe brain injury may be pronounced dead before the heart stops beating.3 In the 1970s, various state legislatures and courts acted to turn this “medical consensus” into a legally recognized standard for determining death. i Not all states took such action; those that did formulated the new brain-based physiological standard and its relation to the more traditional cardiopulmonary standard in often significantly different ways. In 1981, the President's Commission for the Study of Ethical Problems in Medicine and Biomedical and Behavioral Research (hereinafter “the President's Commission”) published Defining Death: Medical, Legal and Ethical Issues in the Determination of Death . In this landmark report, the President's Commission proposed a uniform statute for determining death by the application of two alternative physiological standards: (1) “irreversible cessation of circulatory and respiratory functions” and (2) “irreversible cessation of all functions of the entire brain, including the brainstem.”4
The text accompanying the proposed uniform statute clarified the relationship between the two alternative standards. It said that in almost all cases of human death the traditional standard (i.e., irreversible cessation of circulatory and respiratory functions) should be used, as it always had been. Only in rare cases in which mechanical ventilation is used to support the breathing of a severely brain-injured individual—one who meets criteria similar to those laid out by the Harvard committee—should a brain-based standard be employed.
According to the President's Commission, these latter cases require a non-traditional standard because circulatory and respiratory functions cannot and should not be considered signs of continued life if they are supported technologically . The Commission proposed a useful metaphor for the problem: recognizing death is like looking into a room to see if someone is there. When the window that one usually peers through is obscured—when the curtain is drawn—one should make every effort to find another window. In the case at hand, the “curtain is drawn” by the use of the ventilator to support breathing and (indirectly) circulation. According to the President's Commission, the neurological standard of irreversible loss of whole brain function—the coma dépassé or “brain death” diagnosis—is a second window on the same, biologically real phenomenon of human death. Such a standard is needed only when the traditional standard cannot be used—only when the curtain is drawn on the first window do we need to look through the second.
The President's Commission's model statute was endorsed by the American Medical Association (AMA), the American Bar Association (ABA), and the National Conference of Commissioners on Uniform State Laws (NCCUSL). The NCCUSL published this statute under the name “Uniform Determination of Death Act” (UDDA) and worked to get it passed in all of the states and jurisdictions of the United States . The key section of the Act, Section One, reads as follows:
§1. [Determination of Death]. An individual who has sustained either (1) irreversible cessation of circulatory and respiratory functions, or (2) irreversible cessation of all functions of the entire brain, including the brain stem, is dead. A determination of death must be made in accordance with accepted medical standards.5
Through the NCCUSL's efforts, a significant increase in uniformity has been achieved. Not all U.S. jurisdictions have adopted the exact language of the UDDA, but all of them, without exception, have some form of legal recognition for a brain-based standard of death. ii This recognition allows physicians to declare an individual who is dependent on a ventilator dead before the cessation of heartbeat and respiration if results indicating the coma dépassé or “brain death” condition are obtained upon neurological examination.
The consensus position for using a neurological standard to determine death in the United States may be stated in this way: “Whole brain death”—but no other sort of injury that leaves circulation and respiration intact—is an appropriate standard for determining the death of a human being.
D. The Contemporary Controversy
Today, however, the consensus position is subject to a number of persistent concerns and novel criticisms. There remains considerable public confusion, both about the meaning of the term “brain dead” and about its relation to the death of a human being. There is persistent dissent by some clinicians, philosophers, and other critical observers who have never been convinced that “brain death” is, indeed, the death of the human being. There are, as well, pressures against insisting that declaring death, or at least “organ donation eligibility,” requires the irreversible loss of function in the whole brain. And, perhaps most important, there are critics who have published evidence of ongoing integrated bodily activities in some persons meeting the criteria of “whole brain death” and who have claimed that this evidence invalidates the rationale for today's consensus position. These challenges invite—indeed, they necessitate—a re-examination of the neurological standard enshrined in law and medical practice. In this report, the President's Council on Bioethics offers such a re-examination.
A. Educating the Public
One aim of this report is to illuminate for the American public and its policymakers the complexities inherent in the current legal and medical understanding of death. Certain questions emerge immediately: What is “whole brain death”? How do clinicians determine that such a condition is present in a given patient? What pathophysiological and prognostic facts about the condition support the judgment that “whole brain death” is more than just another case of human injury—that it is, rather, the death of the human being? How can the confusions engendered by the term “brain death” be dispelled?
B. Addressing Challenges to the Neurological Standard
Another aim of this report is to address various challenges to the prevailing view that have emerged over the years. In truth, the clinical and pathophysiological facts about the “whole brain death” condition are better understood today than they were in 1968 or 1981. This improved understanding of the facts invites a re-examination of a standard that crucially depends, for its validity, on those facts. Some critics who have undertaken this work of re-examination have concluded that the neurological standard for death is not justifiable—that, in light of what we now know, only the traditional signs of death are adequate for confidently determining that a human being has made the transition from living body to corpse. Such a conclusion is shared also by a minority that has long held itself apart from the emerging consensus, doubting whether any patient who continues to breathe and whose blood circulates—even with technological help—can confidently be judged already dead . Thus, in this report, the President's Council also reconsiders the philosophical adequacy of the prevailing view on “brain death.”
C. Clarifying the Troubled Relationship Between Determining Death and Procuring Organs
One more critical impetus for this inquiry must be mentioned and explored. As previously noted, the “whole brain death” standard for determining death has also been challenged by critics interested in increasing the supply of organs for transplantation. Additional background will be helpful in understanding the nature of this challenge.iii
A human being whose death has been determined according to a neurological standard is the ideal source of transplantable organs. The reason for this is straightforward: with artificial support of respiration and circulation, blood continues to circulate through the body, thereby maintaining the vitality of organs targeted for surgical removal and thus optimizing their utility for their eventual recipients. If surgeons wait for the more traditional signs of death, the organs endure a period of “warm ischemia” during which they are deprived of nourishing blood and oxygen. While it is possible to procure some organs under these circumstances, concerns about ischemic damage make the heart-beating, “brain-dead” donor the preferred source of organs.iv
The advantage of the “heart-beating cadaver” for transplantation was not missed, of course, by the pioneering physicians and policymakers who advocated early on for the now widely accepted neurological standard. The Harvard committee, for instance, mentioned avoiding “controversy in obtaining organs for transplantation” as one of two primary practical goods that would come from the new understanding of death. v
After the Harvard committee released its report, a group of prominent physicians, philosophers, and bioethicists known as the “Task Force on Death and Dying of the Institute of Society, Ethics and the Life Sciences” (hereinafter “the Task Force”) published an appraisal of the new standard for determining death. In that paper, the group made it clear that, although the conclusions regarding a neurological standard would certainly have the effect of creating “available organ sources,” the neurological standard was not designed solely to accomplish that end.6 It should be noted that there were some who did not accept the Task Force's judgment and suspected that the movement for a brain-based death standard was driven by the need for transplantable organs.
Nonetheless, the Task Force's clarification has largely set the tone for all subsequent debate: The question of whether a human being in the difficult-to-judge state of “brain death” is alive or dead should be answered on its own terms, not with an eye to the practical effects that a new standard for determining death might have. In other words, society must first decide how to understand the condition of ventilator-dependent patients who have suffered the most debilitating kind of brain injury: Are these individuals dead? Can we know that they are dead with the requisite amount of certainty to act accordingly? Only after these questions have been answered can the matter of eligibility for organ procurement be addressed.
The Council's inquiry into controversies surrounding the determination of death is firmly situated in this tradition. The central question addressed by the Council is, Does a diagnosis of “whole brain death” mean that the human being is dead? That is to say, the central question is not, Does a diagnosis of “whole brain death” mean that the human being is eligible to be a heart-beating organ donor?
Even so, it would be unwise to take up the issue of the “whole brain” neurological standard for death without some acknowledgment of the pivotal role that the standard plays in transplantation medicine. In its companion inquiry into the ethics of organ transplantation, the Council examines various policy proposals offered as solutions to the growing gap between the need for and the supply of human organs. It also considers, in particular, ongoing debates about the ethics of procuring organs from individuals with various degrees of neurological injury, including patients in persistent vegetative states. For this reason, some preliminary discussion of how the determination of death fits into the larger picture of organ procurement is warranted.
Organs can be procured from either the living or the dead, but the living donor can only ethically give organs whose removal will not adversely affect his or her ability to live in a relatively healthy state. All organs and types of tissue that are useful for transplant can be taken from the deceased, but only if valid consent has been obtained.vi To count as “deceased,” an individual must meet one of the two standards described in the UDDA. In the majority of cases, the standard used to declare death prior to organ procurement is the neurological standard; to meet this standard, the patient-donor must be conclusively diagnosed with the condition known as “whole brain death.”vii
Some proponents of organ transplantation argue that these ethical constraints restrict access to the goods that transplantation makes possible: improved health for recipients and the opportunity for generous acts by donors and families in the face of loss and grief. To increase the supply of organs, they argue, more leeway should be given to individuals and families to choose organ donation when a human being is, as the law is now construed, near death—that is, before the strict neurological standard for death has been met.
Reforming the practice of organ donation and procurement to make more organs available could take two forms: (1) loosening the standard for determining death, or (2) abandoning what is known as the “dead donor rule”—the requirement that an individual be “really dead” in order to be a heart-beating donor of vital organs.
With the first option, some individuals with brain injuries less severe than “whole brain death” would also be regarded as dead. Some advocates of this measure argue that a person is dead when certain higher brain functions (or mental capacities) are gone. They would endorse changing the legal/medical definition of death to encompass this group and, still following the mandate of the “dead donor rule,” allow them to serve as heart-beating organ donors.7
The second option would leave the legal/medical definition of death as it stands (or even change it to require cessation of circulation), but would allow the removal of organs from brain-injured patients who are very close to death (but not yet dead). In this revised scheme, clear consent for organ removal—which would occur before death—would be required. Proponents of the second option seek to avoid the philosophical tangles of deciding whether a neurological standard for death is justified without losing the benefits that come from removing organs from heart-beating patients. 8
In this report, the Council will contend that arguments for both reform options are unconvincing. As regards the first option, the Council maintains that there is no “looser standard of death” that can stand up to biological and philosophical scrutiny. Arguments that have been made in support of a looser standard are based on an impoverished view of what it is to be a human being. The Council's position on this is elaborated in Chapter Four.
As for the second reform option, that is, abandoning the “dead donor rule” as a guide for practice—the Council believes this is not ethically justifiable. If indeed it is the case that there is no solid scientific or philosophical rationale for the current “whole brain standard,” then the only ethical course is to stop procuring organs from heart-beating individuals. Organ transplantation could continue, but with exclusive reliance on donors whose death is determined by the cardiopulmonary standard under a controlled DCD protocol (see Chapter Six for details). In the majority view of the Council, such a step is not necessary, however, since today's “whole brain standard” is, in fact, conceptually sound.
The discussion thus far has described the current state of the theory and the practice of determining death using a neurological standard. A few important points warrant repeated emphasis: First, the central question of this report is, Are patients diagnosed with “whole brain death” dead as human beings? A related, secondary question is, How should new empirical findings about “whole brain death” be interpreted?
Chapter Two of this report offers a critique of the term “brain death” as a description of the clinical condition of the patients whose status as living or dead is at the center of debate. The term is problematic. Whether patients in this condition are, in fact, dead, is the central uncertainty addressed by this report; therefore, a term employing the word “death”—as “brain death” or “whole brain death” does—is prejudicial to the aims of an open inquiry. With this concern in mind, we propose the term “total brain failure” for the clinical diagnosis that underlies the current neurological standard.
Chapter Three presents a thorough discussion of the clinical and pathophysiological details that must be understood in order to evaluate the validity of a neurological standard for determining death. This chapter has five main parts. Part I is an account of the “vital functions” of breathing and circulation, with an emphasis on the role of the central nervous system in their operation. The chapter then turns to the clinical state, “total brain failure,” that is, the condition typically referred to as “whole brain death.” In Part II, this clinical state is examined from the standpoint of diagnostics: How can clinicians recognize that an injured individual is, indeed, properly diagnosed with this condition? In Part III, the condition is analyzed from the standpoint of pathophysiology: What is going on in the brain and body of a patient with a diagnosis that meets the criteria of “total brain failure”? In Part IV, empirical findings about the condition that have emerged in recent years are explored. These are findings that some consider damaging to the rationale for the “whole brain death” standard. The fifth part of Chapter Three is a comparison of total brain failure with a state of brain injury with which it is often confused—the persistent vegetative state or PVS.
Chapter Four develops in detail two opposing positions on the central question of the report, Are individuals diagnosed with total brain failure — more generally known as “whole brain death” — really dead as human beings? The first of these takes a principled, agnostic posture: We cannot know with certainty that patients with total brain failure are dead or alive and, as a result, such patients should be regarded as living until their hearts stop. The second position in Chapter Four affirms the current neurological standard, but develops an argument for it based on different philosophical premises than those that have become commonplace.
In Chapter Five, we examine the implications for policy and practice of each of the positions described in Chapter Four. We do so with a concern both for the needs of organ transplantation and the need to respect the dignity of patients at the end of life.
Chapter Six explores the practice of controlled DCD. This increasingly common practice in U.S. hospitals provides a family with the opportunity to donate the vital organs of a terminally injured loved one after he or she dies. If the family agrees to donation, then the death of a loved one is monitored in a controlled setting that allows the transplant team to retrieve the organs from the donor as soon as the heart stops. Death is determined by the cardiopulmonary standard, but the timing of the determination is dictated by the requirements of successful organ procurement. For this reason, there can be unsettling ambiguities in the line between life and death with controlled DCD—and thus ethical concerns that merit thoughtful consideration. In Chapter Six, we briefly explore these concerns, which the Council also examines in detail in its report on the ethics of organ transplantation.
In the final chapter, Chapter Seven, we summarize the conclusions of the Council's inquiry into current controversies in the determination of death, taking note of its discussions of ethical concerns in controlled DCD, but focusing on its debate about the biological and philosophical justification of the neurological standard.
_______________________
1.For studies on how often this occurs, see T. J. Prendergast and J. M. Luce, “Increasing Incidence of Withholding and Withdrawal of Life Support from the Critically Ill,” Am J Respir Crit Care Med 155, no. 1 (1997) : 15-20; and S. P. Keenan et al., “A Retrospective Review of a Large Cohort of Patients Undergoing the Process of Withholding or Withdrawal of Life Support,” Crit Care Med 25, no. 8 (1997): 1324-31.
2. P. Mollaret and M. Goulon, “Le Coma Dépassé,” Rev Neurol (Paris) 101 (1959): 3-15. For a survey of the early neurological literature regarding this subgroup of ventilator-dependent patients, see M. N. Diringer and E. F. Wijdicks, “Brain Death in Historical Perspective,” in Brain Death , ed. E. F. Wijdicks (Philadelphia: Lippincott Williams & Wilkins, 2001) : 5-27; E. F. Wijdicks, “The Neurologist and Harvard Criteria for Brain Death,” Neurology 61, no. 7 (2003) : 970-6; C. Machado, “The First Organ Transplant from a Brain-Dead Donor,” Neurology 64, no. 11 (2005) : 1938-42; and C. Machado et al., “The Concept of Brain Death Did Not Evolve to Benefit Organ Transplants,” J Med Ethics 33, no. 4 (2007): 197-200.
3. Ad Hoc Committee of the Harvard Medical School to Examine the Definition of Brain Death, “A Definition of Irreversible Coma,” JAMA 205, no. 6 (1968): 337-40.
4. President's Commission for the Study of Ethical Problems in Medicine and Biomedical and Behavioral Research, Defining Death: Medical, Legal and Ethical Issues in the Determination of Death, (Washington, D.C.: Government Printing Office, 1981). Available online at http://www.bioethics.gov/reports/past_commissions/defining_death.pdf (accessed Oct. 22, 2008).
5. The complete text of the act is available online at http://www.law.upenn.edu/bll/archives/ulc/fnact99/1980s/udda80.htm. (accessed Sept. 26, 2008).
6. Institute of Society, Ethics, and the Life Sciences, Task Force on Death and Dying, “Refinements in Criteria for the Determination of Death: An Appraisal,” JAMA 221, no. 1 (1972): 48-53.
7. See, for instance, K. G. Gervais, Redefining Death (New Haven: Yale University Press, 1986) ; R. M. Veatch, “The Death of Whole-Brain Death: The Plague of the Disaggregators, Somaticists, and Mentalists,” J Med Philos 30, no. 4 (2005) : 353-78; and J. P. Lizza, Persons, Humanity, and the Definition of Death (Baltimore, Md.: Johns Hopkins University Press, 2006).
8. See, for instance, R. M. Arnold and S. J. Youngner, “The Dead Donor Rule: Should We Stretch It, Bend It, or Abandon It?” Kennedy Inst Ethics J 3, no. 2 (1993) : 263-78; N. Fost, “Reconsidering the Dead Donor Rule: Is It Important That Organ Donors Be Dead?” Kennedy Inst Ethics J 14, no. 3 (2004) : 249-60; and R. D. Truog, “Brain Death— Too Flawed to Endure, Too Ingrained to Abandon, ” J Law Med Ethics 35, no. 2 (2007): 273-81. The conceptual case for “eligibility for donation without knowledge of death” was described earlier in R. S. Morison, “Death: Process or Event?” Science 173, no. 998 (1971) : 694-8; R. B. Dworkin, “Death in Context,” Indiana Law J 48, no. 4 (1973) : 623-39; and A. Halevy and B. Brody, “Brain Death: Reconciling Definitions, Criteria, and Tests,” Ann Intern Med 119, no. 6 (1993): 519-25._______________________
i. Whether it truly was a consensus is a matter of historical debate. Certainly there were some prominent physicians and others who did not share the Harvard committee's confidence that those who were properly diagnosed with “brain death” (or “irreversible coma,” as the 1968 report called it) were dead as human beings. Some discussion of this issue can be found in M. S. Pernick, “Back from the Grave: Recurring Controversies over Defining and Diagnosing Death in History,” in Death: Beyond Whole Brain Criteria , ed. R. Zaner (The Netherlands: Kluwer Academic Publishers, 1988) ,17-74; and M. S. Pernick, “Brain Death in a Cultural Context: The Reconstruction of Death, 1967-1981,” in The Definition of Death: Contemporary Controversies , ed. S. J. Youngner, R. M. Arnold, and R. Schapiro (Baltimore: The Johns Hopkins University Press, 1999): 3-33.
ii. Forty-five U.S. jurisdictions have adopted a determination of death act that is either identical to, or shares basic elements with, the UDDA. For details, see H. R. Beresford, “Legal Aspects of Brain Death,” in Brain Death , ed. E. F. Wijdicks (Philadelphia: Lippincott Williams & Wilkins, 2001). A few states have no determination of death statute, but rely instead on precedent-setting court cases, some of which cite the UDDA in their decisions.
iii. A full treatment of the history, practice, and ethics of organ transplantation can be found in the Council's report on that subject, published as a companion volume to this report. The discussion here covers only those facts most relevant to the “determination of death” topic.
iv. Chapter Six discusses procurement of organs (e.g., kidneys, lungs, livers, hearts, pancreata, and intestines) from donors whose death has been determined based on the cessation of circulatory and respiratory function. Also, the remarks here do not pertain to the procurement of what is commonly referred to as “tissue” (as opposed to organs) from a cadaver. In this context, tissue refers to skin, bones, heart valves, corneas, tendons, and veins—all parts of the body that can be taken from a cadaver and put to medical use for another human being. These parts can be taken hours after the heart has stopped beating.
v. The other good it mentioned was relieving the burden on families and caregivers of providing invasive, expensive, and—crucially— futile medical treatment. Today, this problem is less acute since patients and their surrogate decision makers have a greater degree of control over decisions to remove interventions. Doing so does not rely in any way on deciding that the patient is already dead.
vi. For more information on consent policies, see D. Wendler and N. Dickert, “The Consent Process for Cadaveric Organ Procurement: How Does It Work? How Can It Be Improved?” JAMA 285, no. 3 (2001) ; and Chapter Three of the Council's report on organ transplantation.
vii. Cases where organ procurement occurs after a declaration of death by the cardio-pulmonary standard are discussed in detail in Chapter Six.
