الفهرس 
PhysiologyOnly 14 pages are availabe for public view
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Abstract
Life and death has been a phenomenon that has intrigued people of all walks of life since time immemorial. In the classical definition, the loss of heart and lung functions is sufficient to diagnose death. The advents of effective artificial cardiopulmonary support, together with the progressive demand for organ transplantation, have triggered a re-evaluation of this definition.
Determination of death is one of the main problems which meet physicians. Different causes of loss of consciousness obliged physicians to be careful about determination of brain stem death.
In the last 5 decades with the advent of organ transplantation from corpses, the clinical definition of death has taken on functional meaning. The brain rather than the heart is the critical organ that defines death
Coma is clinically defined by the neurologic examination, especially responses to external stimuli. All alterations in arousal should be regarded as acute and potentially life threatening emergencies until vital functions are stabilized, the underlying cause of the coma is diagnosed, and reversible causes are corrected.
The continuing shortfall in solid organs for transplantation has led to renewed interest in the original practice of non heart-beating organ donation from patients pronounced dead following a systole. Improved preservative techniques and better assessment of organs function have enabled transplant teams to procure kidneys, livers and lungs from non heart beating donors.
Organ donor is defined by the presence of either brain death or a catastrophic injury to the brain with the physician’s and the family’s intent to withdraw life support. The diagnosis of brain death requires the absence of brain-stem reflexes, motor responses, and respiratory drive in a normothermic, non drugged, comatose patient with a known irreversible brain lesion.