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Abstract Till the 1950s it was breathing and heartbeat which were taken to signify the continued life of a human being, and it was the permanent cessation of these activities which were taken to constitute human death. However various medical advances throughout the 1950s and 1960s altered the perceived significance of these signs. Recovery from cardiac arrest became more common; mechanical ventilation assisted those not able to breathe spontaneously. Then on December 3rd 1967, the first successful heart transplant was carried out on a human being. The heart seemed not to be irreplaceable after all. Further, if machines could substitute for the function of the heart or the lungs then these organs could not themselves constitute human life. Only the brain seemed irreplaceable in this way; so criteria for death shifted from referring to heart and lungs to referring to the brain. By the end of the 19th century it was known that, during an increase in intracranial pressure, respirations suddenly stopped whereas the heart continued to beat for some time. The widespread use of mechanical ventilators that prevent respiratory arrest has transformed the course of terminal neurologic disorders. Vital functions can now be maintained artificially after the brain has ceased to function. This lead to development of the criteria of brain death the primary concern was to provide an acceptable mechanism to permit withdrawal of mechanical ventilatory support from such patients, and that removal of organs for transplantation was secondary. It is important to stress on the difference between severe brain damage and brain death. The physician must understand this difference, because brain death means that life support is useless, and brain death is the principal requisite for the donation of organs for transplantation. The clinical neurologic examination remains the standard for the determination of brain death and has been adopted by most countries. The clinical examination of patients who are presumed to be brain dead must be performed with precision. The declaration of brain death requires not only a series of careful neurologic tests but also the establishment of the cause of coma, the ascertainment of irreversibility, the resolution of any misleading clinical neurologic Summary 94 signs, the recognition of possible confounding factors, the interpretation of the findings on neuroimaging, and the performance of any confirmatory laboratory tests that are deemed necessary. |