不同脑保护方法的实验研究

Experimental Study of Cerebral Protection in Piglets During Deep Hypothermic Circulatory Arrest

目的 比较单纯深低温停循环(DHCA)、逆行性脑灌注(RCP)和选择性脑灌注 (SCP)不同脑保护技术的效果。方法 15头小型猪随机分成 3组,DHCA组、RCP组和SCP组,三组动物在实验中均降温至食管温度 18℃,90min停循环期间采用不同的脑保护技术,然后复温至 37℃,再灌注时间为 90min。结果 DHCA组血液中PvO2、PvCO2 和脑组织氧摄取率(OER)在低温停循环(DHCA)开始后直线下降,在DHCA60min、90min时,DHCA组与其它两组相比有显著性差异(P<0. 05), DHCA90min时,RCP组与ACP组相比也有显著性差异 (P<0.05),复温再灌注 30min、60min时,三组之间PvO2 值、PaCO2 值以及OER之间存在显著性差异 (P<0. 05),实验结束时,DHCA组PvCO2 仍然较高,未恢复到术前水平,与其它两组相比有显著性差异 (P<0. 05 ),脑组织水含量和电镜检测DHCA组的脑组织水肿严重,RCP组次之,ACP组没有发生脑水肿。结论 DHCA方法简单,但安全时间较短,RCP能在DHCA期间的一定时间内较好地向脑组织提供氧及营养物质,有一定的使用价值。SCP在停循环过程中确保脑的血液供应,保证有足够的时间完成手术,避免了长时间的DHCA所造成脑部并发症。

OBJECTIVE To study cerebral protection during deep hypothermic circulatory arrest, using deep hypothermic circulatory arrest (DHCA), retrograde cerebral perfusion (RCP) and selective cerebral perfusion (SCP).METHODS Fifteen piglets were divided into three groups DHCA group, RCP group and SCP group randomly. Piglets were cooled to 18℃, underwent DHCA for 90 min and reperfusion for 90 min. At the different points of experiment, artery and vein blood gas were analyzed, oxygen metabolism and water content were measured. RESULTS Parameters showed that Pvo 2,Pvco 2 and oxygen extraction rate (OER) levels of DHCA group reached statistics significance between RCP group and SCP group after hypothermic circulatory arrest 30 min(P<0.05). RCP group had significant lower tissue oxygen metabolic levels compared to SCP after DHCA 60 min (P<0.05). Brain edema was present in both DHCA group and RCP group.CONCLUSION In piglet's model, DHCA method is simple, but safe period is very short. RCP prolong safe period in DHCA, but safe period of RCP is limitted to 60 min. SCP is not limited by operative time. SCP is the best method for cerebral protection to provides physiological cerebral blood flow and better cerebral oxygenation.