体外循环期间不同血气管理方法对脑组织血流和氧代谢的影响

目的:比较两种血气管理方法,对中浅低温双瓣膜置换体外循环期间,大脑血流速度和氧代谢的影响。方法:选取连续24例中浅低温体外循环下行双瓣膜置换患者,使用CDI500进行连续血气监测。分别于以下5个时间点:麻醉诱导后(T1),体外循环转机10min时(T2),当鼻咽温降至25℃时,使用α稳态管理并校正血气15min后(T3),后改用pH稳态管理并校正血气15min后(T4),停机后10min(T5),使用经颅多普勒超声仪和近红外线光谱仪,测定大脑中动脉血流速度和脑氧饱和度,评估不同血气管理方法的脑保护效果。结果:与T1相比较,T2、T3脑血流速度和脑氧饱和度均有所减少,但差异无统计学意义(P0.05)。与T3相比较,T4时间点大脑血流速度和脑氧饱和度稍有升高,但差异并无统计学意义(P0.05)。结论:中浅低温体外循环期采用pH稳态血气管理并未明显增加大脑血流速度和氧供。

Effects of pH-stat versus alpha-stat strategies on cerebral blood flow and cerebral oxygen saturation during moderate hypothermic cardiopulmonary bypass

Objective：To compare the effect of alpha-stat versus pH-stat strategies for acid-base management on cerebral blood flow and regional cerebral oxygen saturation in patients undergoing moderate hypothermic cardiopulmonary bypass.Methods：In 24 adult patients undergoing elective double valve replacement operation were studied.The cerebral blood flow （CBF） and regional cerebral oxygen saturation （rSO2） were monitored using TCD and NIRS at five time points：induction of anesthesia（T1）,after 10min of the beginning of cardiopulmonary bypass （T2） and during the moderate hypothermic phase of CPB managed by the alpha-stat after calibrate blood gas 15 min（T3）,and pH-stat followed,after calibrate blood gas 15 min（T4）,10min after CPB （T5） Results：The values of CBF and rSO2 of T2 and T3 were not significantly decreased compare with that of T1 （P ＞ 0.05）.The values of T4 slightly increased compare with that of T3,but it is not significant （P ＞ 0.05）.Conclusion：During moderate hypothermic cardiopulmonary bypass,the cerebral blood flow and the rSO2 were no significantly higher during pH-stat than that of alpha-stat.