Friday, February 19, 2010

The Devilishly Difficult Definitional Determination of Death

"What is a superior set of criteria for death?" I asked. For a moment, the room of 17 jabbering college students went silent. Some of the students looked at each other, asking with their eyes, "who's gonna answer that one?" It's a tough question.

The definition of death is just the flipside of the definition of personhood (see my post on this subject) in my view- essentially one defines when mortal life begins and the second defines when it ends. It seems a little funny/strange to me that a reality so common and fundamental as the span of a mortal life should be so hard to pin down.

Why is the definition of death important? Well, because the resolution of that question is dispositive in so many situations (e.g. organ procurement for transplant, when to bury a person, whether to continue persistent vegetative states, who gets to make these decisions, what medical treatment to give [e.g. give treatment A or B where A) has a 40% likelihood of restoring life and consciousness but has a 60% likelihood of resulting in whole body death and B) has a 90% chance of resulting in an irreversible vegetative state], etc.).

Now back to my story. Up to the point I asked for a superior criteria set for defining death, my bioethics discussion section had vigorously criticized existing candidate definitions. I transitioned to the question by noting that criticizing and constructing are often two separate endeavors. Now I summarize the issue they had debated up to that point.

Most developed countries accept some iteration of brain death as equivalent to death. A Bioethics (the journal) article from last month (ARE RECENT DEFENCES OF THE BRAIN DEATH CONCEPT ADEQUATE) nicely summarizes three popular criteria for death, as well as some rationales and problems associated with each. The three criteria:

1) Whole brain death: irreversible loss of all critical functions of the entire brain.
2) Higher brain death: irreversible loss of the function of the cerebrum.
3) Brainstem death: irreversible loss of the capacity for consciousness and the ability to breathe.

In addition to these criteria, there are several different conceptions of/rationales for death. I'll name three prominent ones:

1) Capacity for consciousness
2) Loss of integrative unity of the organism
3) Loss of the ability to breathe

What criteria and rationale would you choose? I at first wanted to choose whether the organism is a body or a soul (meaning the spirit is inside), but I don't know how to discern whether and when a human spirit is in possession of a body, especially in situations of a coma or a persistent vegetative state. Is the spirit inside, on a temporary vacation, or permanently gone? Is possession of a body by a human spirit a discrete or a continuous reality? How reversible is possession of a body by a human spirit? Because of these difficulties, possession by a spirit offspring of God proves as yet an unworkable criterion. Therefore, because as showed above it is important to establish a definition of death, one should enter the fray and develop a superior, workable definition as I asked the students to do.

Personally, I don't find a lot of merit in the ability to breathe/breath of life rationale because I don't find the need for a ventilator or CPR equivalent to death. However, the substantively irreversible loss of capacity for consciousness rationale does seem useful, though it is only moderately amenable to a binary (rather than gradated) verdict. (e.g. if loss of capacity for consciousness is death, is its presence life? If so, at what point does life begin- sperm, zygote, morula, fetus, infant, and all the other questions raised in my personhood post, etc.). However, a rationale isn't a criterion, and a workable definition needs measurable criteria.

Consequently, my position is mostly in harmony with the students'- namely, that I don't know a superior criteria set to define death. My knee jerk solution is substantive failure of 80% plus of primary organ systems (circulation, brain/CNS function, respiration, digestion, PNS function, etc.), which is more of a whole-body failure and is broader than all three brain death conceptions.

Some of the flaws of brain death= death concepts the author (Joffe) identified:

– many with prolonged survival shows that integrative unity is not lost.8
– many integrative functions continue, showing that the brain is a modulator and
not the central regulator of integrative unity.9
– high cervical spine injury patients lack the same degree of integrative unity as
the brain dead patient.10
– prognosis of death or unacceptable quality of life is not death itself. Prognosis
of death is not a diagnosis of death
– this does not explain why this loss of function is death. This confuses a criterion
of death (loss of brain function) with a concept of death.
– this does not explain why this loss of structure is death. This confuses a
criterion of death (loss of brain structure) with a concept of death.
– this implies person essentialism; that we are essentially persons, and were never
a fetus or newborn.11
– this means that a patient in a permanent vegetative state, with movement, wake
cycles, and breathing, can be buried or cremated in that state.12
– this does not explain why the loss of these functions is death. This confuses a
criterion of death (loss of consciousness and breathing) with a concept of death.
– the capacity for consciousness may not be lost. The cerebral hemispheres may
be relatively spared, leaving the substrate required for the capacity for
consciousness still present.13
– loss of the ‘conscious soul’ suggests Cartesian dualism, implies we can know
when this soul departs the body, and that the soul departs when the ability to
demonstrate consciousness is lost.
– loss of the ‘breath of life’ suggests that the patient with a cervical spinal cord
injury and no ability to breathe is dead while alert and ventilated.

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