Brain Death Pathogenesis and Diagnosis

The criteria of brain death were evaluated in 42 neurosurgical patients in extremis. Repeated clinical and electroencephalographic examinations and continuous recording of ventricular pressure showed that the deterioration could occur suddenly or gradually. Cranial nerve reflexes and cortical EEG activity disappeared simultaneously or at different times. Ventricular pressure equalled arterial blood pressure in the terminal stage. Brain death may be presumed if cranial nerve reflexes and cortical EEG activity are absent. This assumption is supported when the cerebral perfusion pressure is below 10 mm Hg. In the present study the diagnosis was confirmed by total cerebral angiography. When no brain circulation could be demonstrated twice at an interval of 20 minutes, brain death was documented. In most patients spinal reflexes were present for some time afterwards.