Because it is necessary for the heart to be beating and blood, carrying oxygen, to be pumping in and out of such organs at the time of removal. Therefore, the desire for vital organs for transplantation prompted some to look for new and different criteria to declare death which would allow functioning organs to be removed from the patient. Evidently, bodily unity does not derive solely or even irreplaceably from the brain. So much uncertainty prompts even more fundamental questions. These issues, and the underlying discomfort of many Americans concerning this newly created criterion for declaring death, have led some physicians and ethicists to call for return to the traditional criterion for declaring death, centered on cessation of circulation and respiration sufficient to confirm destruction of the circulatory and respiratory systems and the entire brain.
Death is a manifest reality completely different from life.
Truog, Hastings Center Report, January-February 1997, pg. The Collapse of Our Traditional Ethics, St. Martin's Press, 1994. That Respect Life, American Life League, 1996.