摘要
目的 观察全脑缺血 -再灌流兔脑血流及脑血管CO2 收缩反应性变化 ,探讨复苏后过度通气降颅压的临床应用价值。方法 :四血管阻断法制作兔全脑缺血 -再灌流模型 ,随机分对照组和脑缺血组。经颅多普勒超声 (TCD)探测大脑中动脉平均血流速度 (Vm) ,过度通气法测定CO2 诱发的脑血管收缩反应。结果 :缺血组於再灌流 2、 6、 2 4h所测Vm、脑血管CO2 收缩反应性均明显低于缺血前及同时间点对照组 (P <0 0 0 1) ,CO2 收缩反应性以再灌流 2h最低 ,2 4h有所回升。对照组脑缺血前后Vm 及CO2 收缩反应性无显著变化 (P >0 0 5 )。结论 :兔全脑缺血 -再灌流 2～ 2 4h内前脑循环呈低灌注状态 ,脑血管CO2 收缩反应性降低。该结果提示在缺乏脑血流监测的条件下 。
Objective To observe the changes of cerebral blood flow,carbon dioxide(CO 2)reactivity of cerebral vessels in rabbits with global ischemic/reperfusion and explore the values of hyperventilation early after brain ischemia in cerebral resuscitation.Methods Sixteen healthy New Zealand white rabbits were randomly divided into control group and ischemia group( n =8 for each group).The models of global cerebral ischemic/reperfusion in rabbits were produced by clamping both carotid arteries and vertebral arteries for 30 minutes and then removing the clamps .The mean flow velocity( V m)of middle cerebral artery(MCA)was monitored by transcranial Doppler(TCD).CO 2 reactivity of cerebral vessels was induced by hyperventilation.Results The Vm of right MCA and CO 2 reactivity in ischemic group was significantly reduced at the time of reperfusion 2,6,24 hours compared with that of pre ischemia and the control group at the same time (p<0 001).No significant difference of Vm and CO 2 reactivity were found before and after operation in control group.Conclusion The results suggested that from 2 hour to 24 hour after cerebral ischemia,the rabbits with cerebral ischemic/reperfusion were at a state of postischemic hypoperfusion and decreased CO 2 reactivity.The use of hyperventilation early after brain ischemia has the potential to further reduce cerebral blood flow and worsen outcome.
出处
《中华急诊医学杂志》
CAS
CSCD
2002年第5期321-323,共3页
Chinese Journal of Emergency Medicine
基金
北京市科技新星计划资助项目 (95 2 872 90 0 )
