Academic journal article Issues in Law & Medicine

The Brain Stem in Brain Death: A Critical Review

Academic journal article Issues in Law & Medicine

The Brain Stem in Brain Death: A Critical Review

Article excerpt

There is no sure foundation set on blood,

No certain life achieved by others' death.(1)

We would take the issue of brain death from the "misty court of `philosophy'"(2) and examine it in the cool light of medical science and clinical neurology, which will not cut corners and will be as exacting as is humanly possible. We are, after all, physicians and not metaphysicians. We also cannot be prophets of an ethical "slippery slope," although we are well qualified to observe and interpret what has already occurred in these matters.

At the very least, cessation of all functions of the entire brain (the language of the Uniform Determination of Death Act [UDDA]) should be present before declaring brain death. That such cessation is "imminent" is not sufficient or satisfactory as a criterion for organ donation.(3) Dying must never be confused with death.(4)

This article focuses on the practical difficulties encountered by a neurosurgeon or a pediatrician, as potential donors' doctors, in a metropolitan or suburban community hospital. There is a nearby university hospital with a transplantation protocol. Such protocols put emphasis on the "rapid acquisition of physiologically sound organs."(5) This puts the potential donor at risk. The declaration of brain death must be made as soon as possible, usually in less than twenty-four hours. According to the protocol, fresh vital organs should be obtained untainted by any measures the donor's doctor may have taken to preserve his patient's life: e.g., dopamine to maintain blood pressure or fluid intake at a reasonable level to prevent cerebral edema (rather than allowing a fluid overload so as to better preserve the kidneys for recipients).

The statement is too easily made that if the donor's doctor has conscientious reservations regarding brain death, he should withdraw from the case. In a community hospital of two or three hundred beds, there are often only two neurosurgeons. The other neurosurgeon may have the same reservations, so that moral compunctions cannot be easily avoided as in a larger hospital with eight or nine neurosurgeons having a spectrum of opinions on the subject.

Physicians in attendance on dying patients have to understand themselves and their positions regarding reverence for life. Sometimes they find themselves making the best compromise they can between their consciences and hospital and transplant team policy. Such a compromise, like all compromises, is too often unsatisfactory for a conscientious physician as well as the patient, who, if he is not already dead, will certainly be dead after lethal action has been carried out.

Furthermore, a community hospital may not have the facilities to test all the functions of the entire brain, even of the brain stem, as the UDDA specifies.(6)

Structure and Function of the Brain Stem

Two and a half inches in length (6-1/2 cm), the brain stem extends at the base of the brain from the spinal cord at the foramen magnum to the upper border of the mesencephalon. It is a compact tube of neural tissue containing the nuclei of cranial nerves III-XII and ascending sensory and descending motor tracts, both giving collaterals to the reflex-integrating reticular formation. The reticular formation extends throughout the medullary, pontine, and mesencephalic portions of the brain stem and rostrally into the diencephalon so that functionally the brain stem extends higher than its anatomic upper border.

The brain stem subserves cranial nerve functions (III-XII). Through afferent impulses from neck muscles, cervical vertebrae, and vestibules, its motor centers control body position in space.(7) By reflex adjustments in the reticular formation of the medulla oblongata and in the vagal nuclei, the blood pressure and heart rate can vary. (The heart, however, is driven by its own intrinsic pacemaker at a steady rate when central influences are lost. …

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