Redefining Death — Again

Frederick Grinnell is Professor of Cell Biology and founder of the Program in Ethics in Science and Medicine at the University of Texas Southwestern Medical Center, Dallas. His newest book, Everyday Practice of Science: Where Intuition and Passion Meet Objectivity and Logic offers an insider’s view of real-life scientific practice. Grinnell demystifies the textbook model of a linear “scientific method,” suggesting instead a contextual understanding of science. Scientists do not work in objective isolation, he argues, but are motivated by interest and passions.  In the article below he looks at a recent article in Nature about defining death.  Read previous posts by Grinnell here and visit his website here.

An editorial in Nature (1 October, 2009) entitled “Delimiting death” supports the proposal to reconsider the legal definition of death. “Ideally,” writes the Nature editor, “the law should be changed to describe more accurately and honestly the way that death is determined in clinical practice.” The current definition uses the criteria: (1) irreversible cessation of circulatory and respiratory functions, or (2) irreversible cessation of all functions of the entire brain, including the brain stem. However, assessing ‘irreversible’, ‘all functions’ and ‘entire brain’ becomes to some degree a matter of physician judgment. In cases involving organ procurement for transplantation, the physician is under pressure to obtain donor organs that are as fresh as possible. The situation becomes conflicted. “Physicians know that when they declare that someone on life support is dead, they are usually obeying the spirit, but not the letter, of this law. And many are feeling increasingly uncomfortable about it.”

The Nature piece might be dismissed as adding nothing new to the discussion except for the provocative, two part, conceptual definition of death that the editor proposes: (1) “the person is no longer there” and (2) “can never be made to return.” The first part of this definition helps makes clear the symmetry between the most contentious issues of modern bioethics – endings and beginnings of life. The person is no longer there; we can harvest the body for organs. The person is not yet there; we can harvest the body (embryo) for stem cells.

Franz Rosenzweig’s metaphorical description of death — “His I would be only an It if it were to die.” –no longer is just a metaphor. The meaning of human death emerges according to the organization of human life. For a newly formed embryo, death means loss of viability of a single cell. After several cell divisions, loss of viability of a single cell no longer equals death. Rather, death becomes equivalent to development arrest. After 3-4 months of gestation, once the cardiovascular system develops, it becomes reasonable to speak of cardiovascular death. After 6-7 months, once the central nervous system develops, it becomes reasonable to speak of brain death. After development of modern life support systems, once machines can replace heart and brain functions, it becomes reasonable to speak of the person and the body as separated entities. Modern medical technology has succeeded in separating the I from the “living” It. Modern social thinking remains conflicted about accepting this separation.

Using Nature’s conceptual definition of death as a point of departure is unlikely to produce a more easily implemented legal definition of death for two reasons. First, nobody knows the answer to the question “Where is the person?” Indeed, trying to answer this question has become the central focus of cognitive neuroscience research with no consensus in sight except that – which would return us to the current definition of death — the person will be gone after cessation of brain function. Those who support using human embryos for research up to 14 days of embryo life select 14 days not because they know when the person has arrived but rather because they agree that before day 14 the person could not yet have arrived. Second, both from technical and practical points of view, the statement “can never be made to return” will add the word ‘never’ to the ambiguous list of other terms, i.e., irreversible, all functions and entire brain, about which the Nature editor complains. Therefore, given the inherent ambiguity, trying to decide the moment of an organ donor’s death with certainty will continue to have the potential to create a conflicted (or so it might feel) situation of choosing to sacrifice one life to save another. Clinical judgment still will be required as always is the case in the practice of clinical medicine.

If changing the legal definition of death cannot solve the practical problem, is there an alternative? One approach might be to change the informed consent process so as to involve organ donors more explicitly in the choosing process. Some donors will want to gift their organs only after certainty of death. Their wishes oblige physicians to act cautiously in declaring death, even if it means potentially reducing the value of the organs. However, other donors might view themselves as more involved participants whose advanced directives encourage their physicians to act to maintain the value of their organs, even if doing so means instructing the physician to obey the spirit and not necessarily the letter of the law. Instead of deriving a new definition of life’s end as proposed by the Nature editorial, we should aim for better public understanding of how modern medical technology has made defining life’s end so difficult.