犬腹部爆炸伤致脑间接伤早期血流动力学变化的TCD观察

Transcranial Doppler study on the early changes of brain hemodynamics caused by explosive abdomen wounds in dogs

目的 探讨犬腹部爆炸伤后早期脑血流动力学的变化特点。方法 制作犬腹部爆炸伤模型 ,分别于伤后不同时相点用TCD仪探测犬大脑中动脉 (MCA)血流速度 ,计算搏动指数 (PI) ,阻力指数 (RI) ,同时进行MCA的病理形态学观察。结果 伤后 30minMCA的血流速度显著减慢 (P<0 0 1 ) ,伤后 3h最低 ,以后收缩峰血流速度 (Vs)逐渐回升 ,至伤后 2 4h基本接近伤前水平 ,而舒张期末血流速度 (Vd)、平均血流速度 (Vm)始终维持在较低水平。PI、RI在伤后即刻明显升高 (P<0 0 1 ) ,且在 2 4h内持续维持在高水平。MCA的形态学改变以内皮、内膜损伤和动脉平滑肌构筑紊乱为主。结论 腹部爆炸伤致脑间接损伤后 。

Objective To explore the characteristics of the early changes of brain hemodynamics caused by explosive abdomen wound in dogs. Methods A dog model of explosive abdomen was made. After injury the blood velocity of middle cerebral artery(MCA) was measured by TCD. The pulsatile index (PI) and resistance index (RI) were calculated from TCD findings at different time points. Meanwhile, morphological changes were also observed under light microscope and scan electric microscope.Results The blood velocity of MCA decreased dominantly at 30 minutes after injury (P<0 01), and decreased to the lowest level at 3 hours after injury. Then, the velocity of systolic peak (Vs) of MCA began to go up and almost reached the preinjury level 24 hours after injury. The value of diastolic velocity (Vd) of MCA kept at a lower level within 24 hours after injury, while the value of PI and RI rose immediately after injury (P<0 01) and stayed at a higher level within 24 hours after injury. The morphologic changes of MCA showed injuries of endothelium, tunica intima and smooth muscle. Conclusions The hyperemia phase with relative hypoperfusion came quickly after the brain injury caused by explosive abdomen wound.