Traditionally, both the legal and medical communities determined death through the permanent end of certain bodily functions in clinical death, especially respiration and heartbeat. With the increasing ability of the medical community to resuscitate people with no respiration, heartbeat, or other external signs of life, the need for another definition of death occurred, raising questions of legal death. This gained greater urgency with the widespread use of life support equipment and the rising capabilities and demand for organ transplantation. Since the 1960s, laws governing the determination of death have been implemented in all countries that have active organ transplantation programs. The first European country to adopt brain death as a legal definition (or indicator) of death was Finland in 1971, while in the United States, the state of Kansas had enacted a similar law earlier.An ad hoc committee at Harvard Medical School published a pivotal 1968 report to define irreversible coma. The Harvard criteria gradually gained consensus toward what is now known as brain death. In the wake of the 1976 Karen Ann Quinlan case, state legislatures in the United States moved to accept brain death as an acceptable indication of death. In 1981, a presidential commission issued a landmark report entitled Defining Death: Medical, Legal, and Ethical Issues in the Determination of Death, which rejected the "higher-brain" approach to death in favor of a "whole-brain" definition. This report formed the basis for the Uniform Determination of Death Act, since enacted in 39 states.
In Brazil, the Federal Council of Medicine revised its regulations in 2017, including "a requirement for the patient to meet specific physiological prerequisites and for the physician to provide optimized care to the patient before starting the procedures for diagnosing brain death and to perform complementary tests, as well as the need for specific training for physicians who make this diagnosis." In 2020, an international panel of experts, the World Brain Death Project, published a guideline that:provides recommendations for the minimum clinical standards for determination of brain death/death by neurologic criteria (BD/DNC) in adults and children with clear guidance for various clinical circumstances. The recommendations have widespread international society endorsement and can serve to guide professional societies and countries in the revision or development of protocols and procedures for determination of brain death/death by neurologic criteria, leading to greater consistency within and between countries. Medical criteria
Natural movements also known as the Lazarus sign or Lazarus reflex can occur on a brain-dead person whose organs have been kept functioning by life support. The living cells that can cause these movements are not living cells from the brain or brain stem; these cells come from the spinal cord. Sometimes these body movements can cause false hope for family members. A brain-dead individual has no clinical evidence of brain function upon physical examination. This includes no response to pain and no cranial nerve reflexes. Reflexes include pupillary response (fixed pupils), oculocephalic reflex, corneal reflex, no response to the caloric reflex test, and no spontaneous respirations.