Clinical and neurophysiological epidemiology of brain death

Background: Brain death (BD) is the complete and irreversible loss of brain functions. EEG is a diagnostic test that is low-cost and relatively accessible. In Brazil, the estimated rate of BD is 90-100 cases per million people per year. Objective: This study is an epidemiological survey and neurophysiological results of individuals with suspected BD in the region of the Regional Health Department (DRS-VI). Methods: Retrospective study reviewing EEG reports of all BD protocols opened in DRS-VI over a 1-year period. This region comprises 68 municipalities with approximately 1.8 million people. All tests are performed by the OPO team at the Hospital das Clínicas, Faculty of Medicine of Botucatu - UNESP. After a compatible clinical analysis, the complementary test of choice is the EEG. This test is performed according to SBNC recommendations derived from ACNS. Basically, tests are performed with video-EEG recordings, electrode placement according to the international 10-20 system, and lasting 30 minutes including 2 painful stimuli. Results: 107 BD protocols were opened. The estimated incidence was 57 cases per million people. The individuals had a mean age of 48±18 years (min=10 – max=86, 46 women). Regarding etiology: 61% had stroke (n=8 ischemic stroke, n=48 hemorrhagic stroke, and n=9 unspecified), 22% traumatic brain injury, 7% ischemic encephalopathies, 5% neoplasms, 4% neuroinfections, and 2% others. The EEG was compatible with the diagnosis in 90% of cases. In 11 individuals, the test needed to be repeated. In these cases, it was confirmatory in 8 cases, remained inconclusive in 2, and in only 1 patient presented cerebral electrical activity. Conclusion: The incidence of BD in the region is lower than the estimated national rate. EEG helped to rule out one case in 107 and was inconclusive in 2. These findings confirm its importance in the protocol currently used in the country.