RELIABILITY IN DIAGNOSIS OF BRAIN-DEATH

Objective: To compare some of the confirmatory investigations of brain death with clinical criteria in order to achieve the most sensitive a nd accurate diagnosis of brain death. Design: All patients with isolat ed brain lesions and Glasgow Coma Scale (GCS)= 3 were subjected to neu rological examination after ruling out hypothermia, metabolic disorder s and drug intoxications and diagnosed as clinically brain-dead when t he brainstem reflexes were absent and the apnea test positive. Patient s: 15 patients with clinical diagnosis of brain death entered this stu dy. Measurements and results: The patients were submitted to the follo wing investigations: electroencephalogram (EEG), transcranial Doppler (TCD) of the middle cerebral arteries (MCA), cerebral blood flow measu rements with the i.v. Xe-133 method (CBF) and selective cerebral. angi ography (CA). EEG was isoelectric in 8 patients while the remaining 7 patients showed persistence of electrical activity. TCD was compatible with intracranial circulatory arrest in 18 MCA districts, compatible with normal flow in 2 and undetectable in 10 out of 30 districts inson ated. In CBF examinations, however, all the patients showed a characte ristic ''plateau'' of the desaturation curves lasting through the whol e investigation and suggestive of absent cortical flow. CA showed circ ulatory arrest in both carotid and vertebral arteries. Conclusions: Ou r study suggests that cerebral angiography and CBF studies are the mos t reliable investigations whereas the role of EEG and TCD remains to b e determined because of the presence of false negatives and positives.