Effect Of Dexmedetomidin On The Half Effective Concentration Of Bupivacaine Under Ultrasound Guided Sacral Block In Children

Objective:The aim of this clinical trail was to observe the effect of dexmedetomidin on the half effective concentration of bupivacaine under ultrasound guided sacral block in children.Methods:There were 40 cases of pediatric circumcision,intravenous anesthesia combined with ultrasound guided sacral anesthesia in children.The children were randomly divided into 2 groups: Bupivacaine group(group B): Sacral canal injection of 0.2% bupivacaine,bupivacaine combined with dexmedetomidine group(group BD): Sacral canal injection of 0.2% bupivacaine and 1ug/kg dexmedetomidine mixture.The volume of local anesthetic was 1 ml/kg.The concentration of bupivacaine was measured by sequential method.The initial concentration was 0.2%,and the adjacent concentration ratio was 1.1.Blocking effectively reduced the first level concentration and blocked the ineffective increase of the first level until 7 turning points appeared.The onset time of the two groups was observed.The base value(T1)of the children was recorded,before the sacral canal anesthesia(T2),before the cutting of the skin(T3),the change of HR and SBP after the skinincision(T4),and the OAA/S score was used to determine the sedative depth.The EC50 and 95% confidence interval CI of the sacral canal block under ultrasound guidance were calculated for bupivacaine.Results:1.There was no significant difference in the general data of ASA,age and weight in the two groups(P>0.05).2.In group B,the effect of anesthesia was better than that of BD group,and the difference was statistically significant(P<0.05).3.Compared with group B,BD group before skin incision(T3),after skin incision(T4),SBP and HR were lower than B group(P<0.05).There was no statistically significant difference in SBP,HR and OAA/S score between two groups(B)before caudal anesthesia(P>0.05).4.In group B and group BD,the EC50 and 95% confidence interval CI of bupivacaine in the two groups were B group EC50 0.1741%(0.1605%-0.1877%),respectively.Group BD was 0.1414%(0.1267%-0.1561%)(P<0.05),and the difference was statistically significant.5.In this experiment,there was no adverse reaction to the sacral canal anesthesia guided by ultrasound.Conclusion:Combined use of dexmetomidine 1ug/kg reduced bupivacaine EC50 in sacral canal block in children.