Brain Death (BD) or Death by Neurological Criteria (DNC) is a “nerve” racking topic for anyone in the medical field. It is a daunting task to explain, despite the appearance of sleeping, how a patient is no longer alive. This brief review describes the history of BD/DNC and concludes with a practical suggestion to ethically talk about BD/DNC.
Humans have been determining death by using heart and lung function throughout history. Most people are still determined to be dead based on these traditional means. However, technological advancements have complicated this seemingly easy diagnosis.
Why We Needed a New Way to Diagnose Death
In the 1950s, medicine started using mechanical ventilation to support respiration. This mimicry of what we thought defined life created many concerns. Would the patient even want mechanical ventilation? As well as the more existential questions about life itself. Could a patient be dead even though their body is breathing? How can we determine if we are merely ventilating a corpse? Having the technology does not imply a necessity to use it.
In the 1960s, it was a faux pas to discontinue life-sustaining treatments such as mechanical ventilation. Yet there were patients on ventilators who were unable to regain consciousness. Were the physicians saving lives or preserving corpses? If artificial support could sustain respiration and circulation in dead bodies, then clinicians needed another means to determine if the patient was still alive. Was there a state that would be equivalent to cardiopulmonary death?
A New Definition of Death: Brain Death History
Henry Beecher, a Harvard Medical School professor, formed an ad hoc committee to consider this issue. They finalized their work by publishing “A Definition of Irreversible Coma” in 1968. The title is misleading because this article proposed a new criterion for death. One in which the brain loses the ability to maintain life in the body. This new criterion has since become known as brain death (BD), which is shorthand for death by neurological criteria (DNC).
Beecher, et al.’s epoch-making paper fell in the controversial shadow of a momentous procedure in modern medicine. One year before this 1967 publication, South African Christiaan Barnard completed the first heart transplant. The unresolved question is if the donor was dead when they removed the heart, or if the removal was the cause of death. This historical fact inspires the most prevalent concern with BD/DNC. “Was BD/DNC developed as a mere means to provide more organs for donation?” The authors inspired more questions than answers to this concern when they called out transplantation as a necessary reason for their new criteria: “Obsolete definition for the criteria for the definition of death can lead to controversy in obtaining organs for transplantation.”
Total v. Higher Brain Function Argument
Another early question about BD/DNC was how much loss of brain function was sufficient to determine death? Do we need total loss of brain function, or can we get by with only the higher functions that define a human person?
Philosopher Robert Veatch argued for the higher brain standard, in that “Death is the irreversible loss of that which is essentially significant to the nature of man.” Veatch is describing a death that is different from other animals, or even plants. (When my plants die, which is an unfortunately common circumstance, they did not lose a particular function but all functions.) Veatch argued that it is not essential to have a total loss of function, but only the higher brain functions. Thus, the ambiguity around the death of a person began.
The death of a person could mean the death of human characteristics such as personality, memories, etc. Such a person would be permanently unconscious and unresponsive to interactions, but would still have some of the basic functions of life. Such a life would be like that of a persistent vegetative state.
Argument for Total Loss of Neurological Function
We all agree that the things that make up a person, e.g. personality, experience, knowledge, make up what we define as an individual. Yet, it is difficult to use particular neurological functions to define death. The primary reason for this is that injuries to these particular neurological functions may be reversible. Yet, irreversibility is critical to defining death. The brain’s total loss of physiological function defines the severity of the injury. The function does not return from such catastrophic injuries.
For this and many other reasons, clinicians determined that BD/DNC was not only the death of a person but of a body. BD/DNC may include the death of the individual, but BD/DNC means more than that. A BD/DNC diagnosis means that body can no longer maintain its life source, the soul. The body’s life-sustaining neurological functions have ceased.
If we use the total function of the brain, rather than Veatch’s higher function standard, we can be certain that the determination of death is made correctly. When BD/DNC is made reliably, there are no cases of people “waking up”, known as the Lazarus syndrome. Which has occurred after years of a person being in a persistent vegetative state. Using the total loss of function to determine BD/DNC gives us absolute certainty that the body is dead.
Diagnosing Brain Death/Death by Neurological Criteria
The first step in the process is to know what caused the decrease in brain function. Reversible causes, or confounding conditions, may lead to decreased brain function. Without knowing the cause, patients can be misdiagnosed with BD/DNC. Misdiagnosis is not Lazarus Syndrome, but a “brain death mimic.” Thus, to accurately diagnose BD/DNC, the physicians must rule out the confounders before examining the patient.
When physicians examine patients, they look for the absence of a brainstem response, which aligns with the scientific method. The scientists aim to disprove the hypothesis to know with certainty. The unresponsive body is dead. If the body responds, then the clinician disproves the hypothesis. The philosophical question is “Is the burden of proof on disproving life, or proving death?” The clinical question is “Are the criteria they are looking at all-encompassing?”
Potential Error in Medical Diagnosis of Brain Death/Death by Neurological Criteria
There is a certain amount of error allowed in practicing medicine. If lab work is incorrect, the physician can look for something else. But BD/DNC cannot be corrected after diagnosis. Thus clinicians must have absolute certainty when diagnosing a patient with BD/DNC.
One concern worth considering is that BD/DNC patients still have activity occurring in the body. Does this negate the hypothesis that the patient is dead?
Analogously, there is an activity in the bodies of patients declared dead based upon cardiopulmonary function. There are cells in the body that will continue to metabolize after death. But the point is that the whole system is not working to sustain life. Some parts of the neuroendocrine system may still be functioning, but the system as a whole has ceased. None of these lingering operations can continue the life of the body.
Ethical Terminology Recommendation
The Ethical and Religious Directives for Catholic Health Services state that “The determination of death should be made by the physician or competent medical authority in accordance with responsible and commonly accepted scientific criteria” (ERD 62). Thus, we must rely on clinicians to determine the specific biological parameters that indicate death has occurred. Nevertheless, we must recognize that words matter, especially regarding BD/DNC.
The term Brain Death (BD) causes a great deal of confusion. When we talk about death, we are talking about an organism that has died. An organism is a living system that functions as one living entity. Organisms may have organs that can and do fail, causing death. But BD is not simply the death of the brain, it is an abbreviation for death declared by neurological criteria (DNC). DNC is cumbersome to say (hence I am abbreviating it), but it accurately portrays the state of affairs. DNC means that the death of the human being has been determined by looking at the brain and its lack of function.
It is critical to understand that BD is medical jargon. I have had patients request brain transplants. And this makes sense when thinking about the death of an organ. It has become a common practice to receive donated organs to preserve life. DNC clearly states that the body’s life cannot be preserved. Therefore, the patient is dead.
Brain Death or Death by Neurological Criteria is a “nerve” racking topic for anyone in the medical field.
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BD/DNC will always be an emotionally charged issue. Proper education of BD/DNC’s history empowers clinicians and potential patients. Clinicians are responsible for acknowledging these historical issues and the level of patient understanding. I hope we can all work together to increase our community’s knowledge of this delicate topic.
I know it is an uphill battle to change the language of medical jargon… But let me know what you think. Did I miss something in the description of BD/DNC? Do you prefer using BD over DNC? Let me know in the comments below or by Tweeting at me at @PaulWagle.