[Intracranial pressure and brain death]

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. At the end of an ischaemic period of 8 to 10 minutes, absolutely lethal to brain tissue, cerebral death is completed. 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.