脑死亡评估的研究

Studies on evaluation of brain death

目的 探讨准确、客观评估脑死亡的方法。方法 2 0 0 2年 4月至 2 0 0 3年 4月神经重症监护治疗病房采用临床指标及脑电图、脑干诱发电位 (BAEP)、短潜伏期体感诱发电位 (SLSEP)和经颅多普勒超声 (TCD)等实验室指标对 11例脑死亡进行动态评估研究。结果 全部病例深昏迷 ,格拉斯哥昏迷评分 3分 ,脑干反射和脑神经支配的活动消失。全部病例脑电波静息 ,其中 3例存在静息过程。全部病例BAEP主波消失 ,1例存在主波消失过程。全部病例SLSEP的N13以后波形消失。TCD检测除 1例为极重度颅内压增高血流改变外 ,其他全部为脑死亡血流特征。自主呼吸诱发试验和阿托品试验为脑死亡提供了最后的证据。脑死亡的主要原因是呼吸心跳骤停、急性低氧血症和(或 )低血压。结论 实验室多项评估指标结合 ,尤其是临床指标与实验室指标的结合 ,以及动态观察可提高判断的准确性。

Objective To investigate the methods of evaluating brain death accurately and objectively. Methods Various kinds of clinical examination [including conscious state ,Glasgow coma score (GCS),brain stem reflection,cranial nerve dominated actions,spinal reflection,spinal nerve dominated automatic action,respiratory and apnea testing] and laboratory methods [such as electroencephalography (EEG),brainstem auditory evoked potentral (BAEP),brainstem auditory sensery evoked potentral (SLSEP) and transeranial Doppler (TCD)] were used to evaluate 11 cases with brain death. Results Eleven cases presenting with deep coma were conssedered to have brain death. All of them had GCS score of 3 and disappearance of brain stem reflection and cranial nerve dominated automatic action. Six of them patients showed anisocoria. Nine of them pharyngeal reflex could not be detected because of tracheal cannulization,but this did not influence the evaluation of brain death. None of them showed “flat” EEG and disappearience of BAEP dominant wave. None of the SLSEP show any wave behind N13. TCD showed blood stream characteristic of brain death except in one case blood stream characteristic of increased intracraniai pressure. Apnea test and atropine test provided the final proof brain death. The former had more influence on heart rate, blood pressure and oxygen saturation while the latter were more safe and reliable. Conclusion Combined and continuous observation of clinical and laboratory indices can enhance the accuracy of the evaluation of brain death.