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Brain death is the complete and irreversible loss of brain function (including involuntary activity necessary to sustain life).〔(【引用サイトリンク】title=Brain death )〕 Brain death is one of the two ways of determination of death, according to the Uniform Determination of Death Act of the United States (the other way of determining death being "irreversible cessation of circulatory and respiratory functions"). It is not the same as persistent vegetative state, in which the person is "alive". Brain death is used as an indicator of legal death in many jurisdictions, but it is defined inconsistently. Various parts of the brain may keep living when others die, and the term "brain death" has been used to refer to various combinations. For example, although a major medical dictionary says that "brain death" is synonymous with "cerebral death" (death of the cerebrum), the US National Library of Medicine Medical Subject Headings (MeSH) system defines brain death as including the brainstem. The distinctions can be important because, for example, in someone with a dead cerebrum but a living brainstem, the heartbeat and ventilation can continue unaided, whereas in whole-brain death (which includes brain stem death), only life support equipment would keep those functions going. Patients classified as brain-dead can have their organs surgically removed for organ donation; though not everyone agrees with this practice, preferring to limit organ donation to those individuals who have suffered the death of all of their brain and the death of their cardiac and respiratory systems (biological, or full, death). However, if one limits the criteria to those individuals, procuring viable organs can become much more difficult. ==Legal history== 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, as well as rising capabilities and demand for organ transplantation. Since the 1960s, laws on determining death have, therefore, been implemented in all countries with active organ transplantation programs. The first European country to adopt brain death as a legal definition (or indicator) of death was Finland, in 1971. In the United States, Kansas had enacted a similar law earlier. In the 1970s, the Supreme Court of the state of New Jersey ruled that patients and their families have the right to decide when and whether to remove life support. An ''ad hoc'' committee at Harvard Medical School published a pivotal 1968 report to define irreversible coma.〔(Life-sustaining Technologies and the Elderly )〕 The Harvard criteria gradually gained consensus toward what is now known as brain death. In the wake of the 1976 Karen Ann Quinlan controversy, 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 – ''Defining Death: Medical, Legal, and Ethical Issues in the Determination of Death'' – that rejected the "higher brain" approach to death in favor of a "whole brain" definition. This report was the basis for the Uniform Determination of Death Act, which has been enacted in 39 states of the United States〔(【引用サイトリンク】url=http://uniformlaws.org/LegislativeFactSheet.aspx?title=Determination%20of%20Death%20Act )〕 the Uniform Determination of Death Act in the United States attempts to standardize criteria. Today, both the legal and medical communities in the US use "brain death" as a legal definition of death, allowing a person to be declared legally dead even if life support equipment keeps the body's metabolic processes working. In the UK, the Royal College of Physicians reported in 1995, abandoning the 1979 claim that the tests published in 1976 sufficed for the diagnosis of brain death and suggesting a new definition of death based on the irreversible loss of brain stem function alone.〔Criteria for the diagnosis of brain stem death. J Roy Coll Physns of London 1995;29:381-2〕 This new definition, the irreversible loss of the capacity for consciousness and for spontaneous breathing, and the essentially unchanged 1976 tests held to establish that state, have been adopted as a basis of death certification for organ transplant purposes in subsequent Codes of Practice.〔A Code of Practice for the Diagnosis and Confirmation of Death. Academy of Medical Royal Colleges. 70 Wimpole Street, London, 2008〕〔American Academy of Neurology. (2000, January 13).Spontaneous Movements Often Occur After Brain Death.Science Daily.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Brain death」の詳細全文を読む スポンサード リンク
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