经颅多普勒超声在犬腹部爆炸伤后脑血管损伤中的应用

Transcranial Doppler to determine indirect cerebral vascular injury caused by explosive abdomen wound in dogs

目的 利用经颅多普勒超声 (TCD)技术对犬腹部爆炸伤后脑血管损伤进行评价。方法 制作犬腹部爆炸伤动物模型 ,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 伤后即刻MCA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)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 伤后Vd的持续偏低和PI、RI持续偏高可能是脑血管间接受损的特征性表现 。

Objective To evaluate indirect cerebral vascular injury caused by explosive abdomen wound in dogs by transcranial Doppler (TCD).Methods A dog model of explosive abdomen was made.After injury the blood velocity of middle cerebral artery was measured by TCD,and pulsatile index (PI) and resistance index (RI) were calculated from TCD findings at different time.Meanwhile,morphological changes were also observed under light microscope and scan electric microscope.Results The blood velocity of middle cerebral artery slowed down 30 minutes after injury (P< 0.01 ),and down to the lowest level at 3 hours after injury.Then,the velocity of systolic peak (Vs) of middle cerebral artery began to go up and almost reached the preinjury level 24 hours after injury.The value of diastolic velocity (Vd) of middle cerebral artery was 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 was maintained at a higher level within 24 hours after injury.The morphologic changes of middle cerebral artery showed injuries of endothelium,tunica intima and smooth muscle.Conclusions The indirect cerebral vascular injury from explosive abdomen wound may be characterized by a continuously lower level of Vd and a continuously higher level of PI and RI after injury.TCD can be used as an effective evaluation method.