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目的 :探讨异丙酚对体外循环 (CPB)各阶段脑氧及乳酸代谢的影响。方法 :选择心内直视手术病人 31例 ,随机分为异丙酚组 (A组 ) 16例 ,对照组 (B组 ) 15例。分别于CPB前、降温至 33℃和 30℃、低温期、复温至 30℃和33℃以及CPB后 15分钟七个时点测定动脉、颈内静脉血气及乳酸值 (LA) ,并计算脑摄氧率 (O2 Ext)及动脉 颈内静脉乳酸差值 (AVDL)。结果 :两组颈内静脉氧饱和度 (SjO2 )于低温期均明显升高 ,复温时降低 ,SjO2 <6 0 %者占 2 3% (A组 4/16 ,B组 3/15 ) ,两组间无差异 (P >0 0 5 )。B组复温期O2 Ext较低温期增加 (P <0 0 5 )。CPB开始后两组LA均升高并持续至CPB结束。两组AVDL始终接近零 ,LA无差异 (P >0 0 5 )。CPB结束后LA与CPB时间在B组呈正相关 (R =0 744 3,P <0 0 0 1) ;A组二者无相关性 (R =0 0 30 3,P >0 5 )。结论 :CPB复温期间有发生脑氧供需失衡趋势。异丙酚可降低O2 Ext,并在一定程度上防止CPB延长所致的LA进行性升高
Objective: To investigate the effects of propofol on cerebral oxygen and lactic acid metabolism during CPB stages. Methods: Totally 31 patients undergoing open heart surgery were randomly divided into propofol group (A group), 16 cases and control group (B group), 15 cases. Arterial and internal jugular vein blood gas and lactic acid (LA) were measured before CPB, when the temperature was lowered to 33 ℃ and 30 ℃, respectively, at low temperature, rewarmed to 30 ℃ and 33 ℃, and 15 minutes after CPB. Oxygen uptake rate (O2 Ext) and arterial jugular vein lactic acid difference (AVDL). Results: The levels of SjO2 in both groups increased significantly at low temperature and decreased at rewarming. SjO2 <60% accounted for 23% (group A 4/16, group B 3/15) There was no difference between the two groups (P> 0.05). In group B, O2 Ext increased at a lower temperature (P <0.05). After the beginning of CPB, both groups of LA increased and continued until the end of CPB. The two AVDLs were always close to zero, with no difference in LA (P> 0.05). There was a positive correlation between LA and CPB time in group B at the end of CPB (R = 0 744 3, P <0.01). There was no correlation between LA and CPB in group A (R = 0 0 30 3, P> 0 5). Conclusion: The imbalance of supply and demand of cerebral oxygen occurred during CPB rewarming. Propofol decreased O2 Ext and to some extent prevented the progressive elevation of LA due to CPB prolongation