Wiener medizinische Wochenschrift
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The cause of brain death must be known irreversible primary or secondary structural damage of brain and brain stem. The clinical signs and symptoms of the irreversible cessation of brain functions enable to diagnose brain death. An EEG at maximal gain reflects absence of cerebral electrical activity. ⋯ Angiographic, sonographic or other methods to assure cessation of cerebral blood flow but also other methods as the apnea test etc. are helpful but seem to be not necessary. Nearly in every case typical signs and symptoms of an acute midbrain- and bulbar brain syndrome can be diagnosed in the pre-stage of brain death. In about 60% medullary-initiated movements and spinal reflexes can appear and persist for prolonged periods in brain dead patients.
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Cerebral death occurs during reanimation as an isolated destruction of the entire brain. It is the result of a malignant and irreversible increase of the intracranial pressure. Continuous registration of the intracranial and systemic blood pressures which is done as a routine monitoring procedure in the majority of deep coma patients, allows to identify the moment when cerebral perfusion has come to a complete standstill, and also allows to confirm its irreversibility. ⋯ To be on the safe side, the expiration of a 15 to 20 minute period of complete circulatory arrest within the cranial cavity is recommended before further diagnostic measures, especially cerebral arteriography, are undertaken as final proof of dissociated brain death, permitting the explantation of vital organs for grafting. At present, due to possible technical difficulties, reliance upon epidural intracranial pressure measurement alone must still be discouraged. Nevertheless, this investigation method can be most useful in the early timing of the so-called terminal angiography in order not to delay the diagnosis of brain death and its medical consequences.