经颅多普勒超声对脑死亡的观察(4例报告及文献复习)

Evaluation of Brain Death by Using Transcranial Doppler

应用经颅多普勒(TCD)超声仪动态观察了4例临床脑死亡病例演变过程。发现4例均有相似的变化:首先表现为大脑中动脉血流频谱切迹加深,舒张末期流速值(Vd)进行性下降,脉博指数(PI)增高;继之,Vd消失,PI继续增高;最后出现舒张期逆向流速,形成特征性"双向TCD"波型,直至TCD信号消失,患者进入临床脑死亡状态。说明TCD是诊断脑死亡的有用手段。

Transcranial doppler (TCD) was used to measure the flow velocities of middle cerebrial artery (MCA) in 4 patients of clinical brain death. The reaults showed that the changes were similar in all the patients studied; 1) the dierotic notch (DN) was deeper in the spectrum of flow velocities of MCA, end diastolic flow rate (VD) significantly decreased, and the pulastility index (PI) increased ; 2) VD decreased progressively; 3) all patients showed characteristic to-and-fro TCD pattren with antegrade flow in systole and retrograde flow in diastole; 4) the pattern totally disappeared when the patients were claimed dead. It is found that TCD is valuable for the determination of brain death.