[Diagnostic criteria for brain death].
The diagnosis of brain death is made based on the clinical and EEG criteria. Clinical criteria include deep coma, loss of spontaneous respiration, and loss of all the brain stem reflexes. EEG should show electrocortical silence. The EEG examination should fulfill the technical criteria proposed by the Japanese as well as the American EEG societies. In Japan, the Ministry of Health and Welfare criteria for brain death was presented in 1986 after the collaborative study headed by Professor Takeuchi. Those patients with metabolic and endocrine coma, and those under the influence of central nervous depressant drugs or low body temperature should be excluded. Japanese criteria is the most strict one compared to those of other western countries. The most important and frequent source of error in the diagnosis of brain death in which actually alive patients are misdiagnosed as brain death is inappropriate EEG examination. Unless the gain of EEG machine is increased to either 4 (2.5 microV/mm) or 5 (2 microV/mm) with long distance bipolar and monopolar leads, absence or presence of electrocortical silence cannot be evaluated. With this condition, it is imperative to prove that no brain-derived activities above 2 microV are present to make a diagnosis of electrocortical silence (flat EEG). The author believes that as long as the strict clinical and EEG criteria are carefully followed by a specialist, there would be no mistake in the diagnosis of brain death.
Mizuno
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Department of Neurology, Juntendo University School of Medicine.
D001926:Brain Death / Q000175:diagnosis*; D004569:Electroencephalography / Q000379:methods; D006801:Humans