昏睡患者の脳波と聴性脳幹反応—聴性脳幹反応による脳死の判定

CORRELATION BETWEEN EEG AND AUDITORY BRAINSTEM RESPONSE (ABR) IN COMATOSE PATIENTS:DIAGNOSIS OF BRAIN DEATH BY ABR

　抄録　Deep coma 21例と臨床的に脳死と判定された29例を対象に聴性脳幹反応（auditory brain-stemresponse,ABR）と脳波の検討を行ない，脳死を判定する際にABRによる脳幹機能の検索が有用か否かの検討を行なった，脳波に何らかの活動の認められた症例では，全例にABRのI波からV波までの波形が認められた。また，脳波の優位波とI-V波間潜時の関係においても脳波の状態とABRの変化には一定の関係は認められなかった。脳波がisoelectricで臨床上脳死と判定された29例中11例にABRのI波からV波までの波形が認められ，I-V波間潜時も8例が4.4msec以内とほぼ正常反応に近く，従来の脳死者のABR観察の報告と與なり，脳波がisoelectricであり脳幹反射が消失した例にもABRが正常に認められた。脳波，ABRと子後との関係ではABRが無反応で脳波がisoelectricであったものは全例死亡した。臨床的に脳死を判定する際には，脳波のisoelectricのみでなく脳幹反射にABRを加え脳幹機能を十分に検討する必要性があると考えられた。

ABRs and EEGs were recorded from fifty co-matose patients. Among them 21 patients were in deep coma and remaining 29 were in brain death that was diagnosed from clinical criteria.

All the patients who showed some activity in EEG had ABR which showed waves I through V. However, there was no correlation between grade of EEG classification, dominant alpha, theta, or delta ryhthm, and the inter wave latenciesbetween waves I through V in the ABRs.

Eleven of the twenty-nine patients who were diagnosed as brain death from clinical criteria and isoelectric EEG showed waves I through V potentials in ABR. Eight of these eleven patients even exhibited normal or nearly normal ABRs which had I to V latencies less than 4. 4 ms. However, all the patients who showed isoelectric EEG and no response ABR died.

Thus it is concluded that the ABR should be included for identification of brain death in addi-tion to the clinical examination and EEG record-ings.