Bioethics Forum Essay
Individuals Declared Brain-Dead Remain Biologically Alive
A remarkable experiment was reported last week in which a kidney from a genetically modified pig was attached to blood vessels in a brain-dead individual, with the family’s consent. In the study, hailed as “a huge breakthrough,” the pig’s kidney functioned normally, suggesting the future feasibility of successfully transplanting organs from pigs into human beings. This research raises a host of ethical issues, including the ethics of xenotransplantation. Here I focus on the implications for the status of individuals declared brain-dead, or dead by neurological criteria, who are unable to breathe spontaneously and are being maintained in hospitals with the aid of mechanical ventilation.
It is interesting that an article in The New York Times initially described the subject in the experiment as being “kept alive on a ventilator” –a common description of a person declared brain-dead. In a version published two days later, “kept alive” was changed to “sustained.” Presumably, this wording change was meant to be consistent with the stance that the brain- dead are truly dead. However, there is no way that the experiment could have been a success had the human body attached to the pig’s kidney been a genuinely dead body. Connecting the pig’s kidney to a cold human corpse, following determination of death based on irreversible cessation circulatory and respiratory functioning, would never have permitted normal functioning of the kidney. In other words, the biological life continuing in the brain-dead research subject made it possible for the experiment to be a success.
For the past 50 years, the field of bioethics has continued to endorse the consensus view that people declared dead by neurological criteria are dead based on a biological conception of death. This view was developed and defended in the 1981 report of the President’s Commission for the Study of Ethical Problems in Medicine and Biomedical and Behavioral Research, “Defining Death,” and it was affirmed in 2008, with a somewhat different rationale, by the President’s Council on Bioethics in a report, “Controversies in the Determination of Death.” The consensus has prevailed in bioethics and in the medical and legal professions despite challenge by some bioethics scholars who have appealed to evidence that those declared brain-dead continue to maintain a variety of homeostatic functions of the organism as a whole, supported by mechanical ventilation and other medical interventions.
Recently, along with Michael Nair-Collins and Robert Truog, I argued that it is time to abandon the stance that brain-death constitutes biological death in the context of a detailed analysis of a case of a woman pronounced dead by neurological criteria who gestated a fetus and gave birth to a healthy child while being sustained with intensive care in a German hospital for over seven months. The body of this unfortunate woman gave birth to a healthy child. Her heart, both kidneys, and her pancreas were donated for transplantation, in accordance with her prior expressed preferences. The pig kidney experiment offers further evidence that those who are considered brain-dead remain alive.
The consensus regarding the status of brain-dead individuals cannot withstand critical scrutiny. As Daniel Patrick Moynihan famously declared, “Everyone is entitled to his own opinions, but not to his own facts.” The fact that individuals declared brain-dead remain biologically alive leaves open how to think ethically about the status of these living human beings with profound, irreversible brain damage—alive but having irreversibly lost consciousness. How is it possible for “the dead donor rule”—which requires that vital organs can be procured only from individuals validly determined to be dead—to be followed while obtaining organs from brain-dead donors? Do physicians have the unilateral authority to stop life-sustaining treatment for individuals determined to be brain-dead over the objection of family members who insist on maintaining treatment?
Many issues in bioethics continue to be perplexing and controversial; however, bioethics analysis and judgment should always be based on solid evidence of matters of biological fact.
Franklin G. Miller, Ph.D, is a professor of medical ethics in medicine at Weill Cornell Medical College and a Hastings Center fellow.