- BIOETHICS FORUM ESSAY
Procuring Hearts after Cardiac-based Death: Questions About Infant Heart Donations
We sometimes hear a physician say a patient suffered “clinical death” and was brought back to life by CPR. This is, of course, wrong. The patient was never dead. (Otherwise, organs could have been procured if the temporarily “deceased” person had a donor card, the patient’s wife would be a temporary widow, life insurance would pay off, and many other absurd consequences would have resulted.) The patient suffered cardiac arrest and would have died without the resuscitation, but there is only one death per person, at least in this world.
It turns out that becoming dead based on cardiac criteria is more complicated than most of us realize. There was a time when it was the only way to die and no one agonized over exactly what it meant. Now, in the era of so-called “brain death,” some doubt that a heart that has stopped beating is ever the direct indicator that someone has died. Nevertheless, most people are pronounced dead the old-fashioned way.
The cardiac criterion has also become important for increasing the supply of transplantable organs. “Donation after cardiac death,” or DCD, accounted for 605 deceased organ donors in the period from July 2005 through June 2006. None of the organs were hearts, however, or at least none of them should have been. Death pronouncement requires irreversible loss of the critical function–brain function for brain-based death pronouncement or cardiac function for cardiac-based pronouncement. Logically, one cannot procure a beating heart after cardiac function has stopped irreversibly–or so we thought.
The August 14 New England Journal of Medicine reported that for the first time hearts were obtained following cardiac-based death. Three terminally ill babies were pronounced dead after withdrawal of life support. With their parents’ permission, their hearts were successfully transplanted into other babies. There was a problem, however. The babies could not have been dead. If the heart function was irreversibly stopped, it could not have been restarted.
Figuring out when cardiac function has stopped irreversibly and when death has occurred turns out to be a harder problem than we realized. First, some of us are increasingly skeptical that even irreversible stoppage of cardiac function, by itself, means death. Consider a bizarre case of a heart physically destroyed in a person who, by some miracle, remains conscious for a few seconds. In those seconds, the person is surely still alive. That person remains alive until, after a brief period–a few minutes–all of the brain tissue dies. However, current law says that the person died the instant the heart function ceased permanently.
It seems likely that permanent cardiac function loss is really only an indirect indicator that something has happened to the brain. Normally, by the time cardiac function has been determined to be irreversibly gone, the brain is dead and the subtleties are irrelevant, but occasionally it might be possible for the cardiac criterion to be met temporarily when the brain criterion is not. This suggests that the current law, which permits the use of either irreversible loss of cardiac or brain function to signal death, may not be exactly right. It might be better to make explicit that the cardiac criterion can only be used as an indirect indicator of the death of the brain tissue and then only when empirical evidence supports such a link.
For now, however, the law permits death pronouncement as soon as irreversible loss of cardiac function is established. That is what was used in the infant heart procurements even though surely the infants had not sustained permanent destruction of their brain tissue when they were pronounced dead. In addition, though they were pronounced dead based on irreversible loss of cardiac function, the meaning of “irreversible” is ambiguous.
Most people would understand it to refer to what I would call physiological irreversibility meaning that physically the function cannot be restored. There is a second meaning, however. I call it legal irreversibility, meaning it would be illegal to reverse the function loss even though physically it could be done. It would be illegal in the case in which the patient or surrogate has refused CPR. In that special case, some people controversially claim the function loss is irreversible once a heart cannot spontaneously restart (that is, after what is called autoresuscitation is impossible). I have not objected to this controversial way of establishing irreversibility, but it is surely debatable.
Most DCD organ donations follow death pronouncement on this basis. It requires empirical evidence about how long a heart must be stopped before autoresuscitation is impossible. The original University of Pittsburgh protocol used two minutes, but most critics have thought this was too short, leading an Institute of Medicine committee to propose five minutes, which is used by most centers today. Many people, especially practically-minded clinicians, have almost lost site of the fact that the time of asystole (heart stoppage) is important only in cases in which resuscitation would be illegal.
The New England Journal of Medicine study reveals that, in two cases, the infants who supplied organs were pronounced dead after only seventy-five seconds. Many have correctly pointed out that there is no consensus that this short period proves irreversibility. There should at least be peer-reviewed documentation. All of that misses the point, however, that autoresuscitation is relevant to irreversibility only when external resuscitation is impossible. In the recent heart procurements, restarting the heart was not only planned; it was successful. As I argued in my commentary in the New England Journal of Medicine, reversed stoppages cannot be consistent with irreversibility. The babies were not legally dead when their hearts were removed. Under present law it is simply impossible to procure usable hearts following death based on cardiac criteria.
That raises the question of whether the law should be fixed so that these hearts could be procured legally. One option long supported by Robert Truog as well as by Jack Kevorkian would be to legalize the killing of certain living patients by physicians by procuring their organs including their hearts. I don’t think it will happen. I don’t think it should happen. Legalizing intentional killing to get organs is too controversial and isn’t going to generate majority support in legislatures. Such killing by physicians would be rejected by most members of the profession as well.
We could clarify what we mean by “irreversibility” by legalizing reversals once a heart has been removed, even though resuscitation has been refused until that time. We would presumably have to specify that the irreversibility criterion need only apply to the time when the heart was in the original body. Nothing in the current law suggests this, but the law could change. This would still leave the problem of removing a heart before brain tissue has died; therefore, we might want to impose a waiting time following asystole long enough for the death of the brain to occur. Then all such deaths would clearly be based on brain criteria and no issue would remain in procuring hearts or other vital organs. This is the practice I personally would prefer.
There is real philosophical and religious disagreement over what it means for a human to be dead. No amount of scientific evidence can establish whether we should classify humans as dead when cardiac function or brain functions cease irreversibly. Among those who favor brain-based definitions, no thinking person now believes that literally all functions of the entire brain must be destroyed before death is pronounced, even though that is what the law requires. An increasingly large minority (as many as 30-40 percent) accept the idea that death occurs when there is irreversible cessation of brain tissues responsible for consciousness (even if other brain tissues survive).
The reasonable public policy would be to handle the definition of death the way we handle other matters of philosophical and religious dispute. We permit individuals to have the freedom to choose philosophical or religious positions as long as it does not have serious impact on the public interest. I have long argued that a society should choose some default definition of death–probably some form of brain death–and permit individuals, within reason, to exercise their consciences to pick a definition to be used in their own cases. I believe that should include the right to choose irreversible cardiac function loss or irreversible loss of consciousness as well as the default definition.
Presumably, parents and surrogates would be permitted to exercise this choice for children and others who have never expressed their views while competent. That would permit procuring beating hearts from some permanently unconscious patients because we consider them deceased. There is no way, however, that heart procurement could or should ever be permitted following what we now recognize as cardiac-based death. One cannot reverse the irreversible.