Posted on April 30, 2018 at 7:32 PM
by Robert M. Veatch, Ph.D.
In 2017, 10,288 people in the U.S. donated organs after they died. Most were pronounced dead using brain criteria, but 1883 were declared dead the old-fashioned way (using circulatory criteria) because their hearts had stopped beating. They became so-called DCD or “Donation after Circulatory Death” donors. When the heart stoppage indicates that circulation has ceased, the physician pronouncing death must wait to make sure that the heart will not spontaneously restart. Restarting is referred to as “autoresuscitation.” The waiting period (sometimes called the “no-touch period”) is often—but not always–based on the time needed to rule out autoresuscitation and is quite controversial. In practice it ranges from as little as 75 seconds, the time used in a controversial heart procurement from some newborns in Denver, to as long as 20 minutes, the legally required “no-touch” period in Italy. The University of Pittsburgh once recommended 2 minutes; The Institute of Medicine, 5 minutes.
DCD organ donation occurs in two ways: (1) Controlled [cDCD], from people who die planned deaths after refusing life-support, and (2) uncontrolled [uDCD], from people who have heart attacks and resuscitation fails. Particularly in the case of cDCD, the waiting time is critical since every second risks damage to organs, but we do not want to take organs before death has occurred. This raises the question of whether DCD donors are really dead. It is a more complicated question than some would think.
In the definition of death debate I estimate that about 15% believe that peopleare dead only when the circulation has irreversibly ceased regardlessof whether the brain is dead. The remainder believe that people are dead when the brain (or some portion of the brain) irreversibly ceases to function. Here is the problem: The common practice of waiting until autoresuscitation is ruled out should be important to the 15%, but usually not to the majority (about 85%) who believe that one is dead when brain function ceases irreversibly. There is no reason to believe that brain function is lost at the exact moment autoresuscitation is ruled out. Brain tissue may survive after autoresuscitation is ruled out, in which case relying on ruling out autoresuscitation to pronounce death could mean pronouncing too early. With really short no-touch times, ruling out autoresuscitation could even leave, at least theoretically, a still-conscious patient. Conscious patients are not dead. Under current law, even permanently unconscious patients for whom restoration of brain function is possible are not dead. On the other hand, brain tissue may die before autoresuscitation can be ruled out, in which case death pronouncement would come unnecessarily late. What the majority who believe in brain-based death should be interested in is the moment the brain can no longer function, not the point at which autoresuscitation is ruled out. It is not clear whether ruling out autoresuscitation requires too long or too short a wait, but either way autoresuscitation should be almost irrelevant.
I say “almost” because there is one relevant connection between autoresuscitation and brain-based death. An additional dispute exists among defenders of brain-based death pronouncement. Some would insist that, for death to be pronounced, it must be physiologically impossible for the brain to function again. Others would merely insist that, in fact, the brain will actually not function again. The difference is that in the latter case, the tissue physiologically may not be dead. It could be stimulated to function by medical intervention like CPR, but will not be because a valid decision, such as with an advance directive, has been made not to intervene. This is sometimes called the difference between “irreversible” and “permanent” stoppage, where “permanent” captures the idea that it could be restarted, but will not be. I have referred to this same distinction as the difference between “physiological irreversibility” and “moral or legal irreversibility.”
Autoresuscitation raises different issues depending on whether one favors physiological irreversibility or mere permanence. If one opts for requiring physiological irreversibility, death should be pronounced whenever it is physiologically impossible to restore brain function. Autoresuscitation is completely irrelevant. If autoresuscitation can be ruled out before physiological irreversibility, one must still wait until that point is reached. On the other hand, if it becomes physiologically impossible to restore function before autoresuscitation can be ruled out, death can be pronounced at the earlier point. Either way autoresuscitation is irrelevant.
On the other hand, if one opts for permanence, the story is more complicated. There comes a point at which the heart has stopped and no one will intervene because of an advance directive. If the brain tissue is known to be destroyed before the point at which autoresuscitation can be ruled out, then it is still appropriate to pronounce death. If loss of brain function is physiologically irreversible, then the loss is permanent regardless of whether the heart could restart itself. On the other hand, as long as it is physiologically possible to resume brain function, the fact that one has a valid decision not to intervene to resuscitate does not justify death pronouncement until resumption of circulation can be ruled out. If brain function would be restored if the heart resumed, then autoresuscitation could still restore brain function.
The conclusion is complex. In many instances autoresuscitation is irrelevant to pronouncing death in DCD cases. It is irrelevant when one believes that death is brain-based and physiological irreversibility is required. It is also irrelevant for pronouncing death when one believes that death is brain-based and all that is required is a permanent cessation of the relevant brain functions as long as physiological irreversibility precedes ruling out autoresuscitation. On the other hand, autoresuscitation remains relevant for the minority who believe death is fundamentally irreversible loss of circulation. For that minority, circulation is critical, regardless of the absence of brain function. Autoresuscitation is also relevant for the majority who favor some version of a brain-based definition of death, but only if mere permanence (rather than physiological irreversibility) is required andit is believed that destruction of brain tissue occurs after the point at which autoresuscitation can be ruled out. The longer the waiting time to rule out autoresuscitation, the more likely brain tissue is to be destroyed before autoresuscitation can be ruled out therefore, making autoresuscitation irrelevant. On the other hand, with very short no-touch times, it is less likely that brain tissue is destroyed at the time autoresuscitation can be ruled out. It that case, autoresuscitation becomes critical for those satisfied with mere permanent loss of brain function since restarting the heart would be more likely to restore brain function. If, however, brain tissue cannot be restored, the patient is dead based on brain criteria even if autoresuscitation is possible. For most of us autoresuscitation is probably not a meaningful indicator of death and thus DCD protocols that rely on it should reconsider that stance.