The Observation Of Propofol's Effects On Cerebral Protection And Hemodynamic During Mild Hypothermia Cardiopulmonary Bypass

Objective:This study was designed to evaluated the neuroprotective effects of propofol and its adverse effects on circulation during mild hypothermia cardiopulmonary bypass,so as to determine the appropiate clinical dosage of its.Methods:Thirty consecutive patients,age 25～40years and cardiac functionⅡ-Ⅲ, undergoing elective mitral valve replacement surgery,were randomly allocated into three groups:group I (n=6) propofol 2mg/kg.h,group II propofol 4mg/kg.h (n=6), groupIII(n=6) propofol 6mg/kg.h,were maintained until the end of surgery by infusion.MAP,JVP,CVP were monitored during operation.Before induction of anesthesia(T1),just before the Cardiopulmonary bypass(CPB) (T2),just at the end of CPB (T3), and 24 hours after operation(T4),Simultaneously from radial artery 2ml bloodsamples were collected, lml of which used to detect Pa02,Sa02,Hb,Hct,La,and another 1ml used to detect Ga; 4ml bloodsamples were collected from internal jugular vein,1ml of which used to detect Pjv02 Sjv02 Lv,1ml used to detect Gv,and another 2ml used to detect CKBB. Based on the above indicators calculate arterial oxygen content(Ca02),jugulary vein oxygen content(Cjv02),arterial-vein oxygen content difference(AVD02),cerebral oxygen extraction rate(CE02),lactate oxygen index(LOI),Arterial-vein lactate difference(AVDL),cerebral lactate Production (CLP),aterial-vein glucose difference(AVDG),and glucose extraction rate(CGU).All the above indexes were analyzed by statistics.Result:(1)Hemodynamic:group III has the biggest fall in MAP,CPP,being the significant differences when compared to I andⅡ(P<0.05).(2) Cerebral oxygenation: LOI were higer than were higher in group I than in group II amdⅢ(P<0.05);whereas There were no significant changes in Ca02,Cjv02,AVD02,Sj02 and CE02 among three groups (P>0.05).(3) Cerebral oxygen metabolism:Lv,AVDL,CLP were higher in group I than those in group II amd III (P<0.05).(4)braim injury:CKBB were higher in group I than those in group II amd III (P<0.05).Conclusion:The propofol of 4mg/kg.h has better crebral protection,meanwhile has less adverse effects on circulation.