蛛网膜下腔出血对ICP、rCBF及死亡率影响的实验研究

Comparative Study of Mortality, Cerebral Perfusion Pressure, Intracranial Pressure and Regional Cerebral Blood Flow under Different Severity of SAH

目的 :研究不同严重程度SAH对颅内压 (ICP) ,脑灌注压 (CPP) ,局部脑血流量 (rCBF)及死亡率的影响。方法 :建立一种新的大鼠颈总动脉 视交叉前池体外转流蛛网膜下腔可控制性出血动物模型 ,比较出血 3 0 ,60 ,90s及重复 3 0s 3次出血后上述指标的变化。结果 :SAH后ICP急剧上升至接近平均动脉压水平 ,当ICP超过 6kPa(80mmHg)即可引起部分动物呼吸抑制而死亡 ;60s和 90s出血组ICP水平相差未具显著性 ,提示在此期间内出血可能趋向停止 ;SAH后rCBF立即受到大幅抑制 ,其后恢复程度与SAH严重程度呈反比。结论 :SAH后ICP剧升引起呼吸功能衰竭是死亡的主要原因 ;SAH后普遍存在脑微循环障碍 。

Aim:To study the effect of different severity of SAH on intracranial pressure, regional cerebral blood flow and acute mortality.Methods:A new rat common carotid artery prechiasmal cistern extracorporeal shunt model of SAH was developed. 36 rats were divided into 4 groups. which were subjected to 30,60,90 s and repeated 30 s of SAH attack respectively. The rats' IPC, rCBF and CCP were monitored and their mortalities were calculated. Results:SAH caused dramatic increase of ICP, which have direct relation to mortality when ICP was over 6 kPa (80 mmHg). Comparison between 60s and 90s groups showed no significant increase of ICP, which may suggest the occurrence of hemorrhage arrest, inferring clinically aneurysmal SAH may not persist much longer than one minute in a survival case. rCBF was suppressed sharply after SAH and recovered slowly to a certain extent in a SAH severity dependent manner.Conclusion:Suppression of brain stem function by sharp increase of ICP is a major cause of death after SAH; disturbance of cerebral microcirculation is a widely existed phenomenon,suggesting an anti ischemia therapy be adopted as soon as possible.