The Clinical Investigation Of Target-Controlled Infusion Anesthesia With Midazolam Alone And Midazolam-Ketamine During Sacrul Block In Children

Objective To investigate the feasibility of target-controlled infusion anesthesia with midazolam alone and midazolam-ketamine (subdissociative dose)during sacrual block and to determine the interaction between midazolam and ketamine in children , also to assess the values of bispectral index(BIS)and heart rate variability(HRV)on measuring the depth of midazolam-ketamine anesthesia and the efficiency of predicting movement during the surgery.Methods One hundred ASA I-II chidren(2-6 years old)undergoing selective surgery were randomly assigned to two groups(50 cases each group)according to different anesthesia.Both groups received sacrul block ,then group MS received midazolam alone and group MKS received midazolam with subdissociative dose ketamine respectively.The non-invasive BP ,HR,finger plethysmograph, electrocardiogram and electroencephalogram were monitored ,bispectral index and heart rate variability and the active movement were recorded. In the observing processes,the hemodynamic changes were infinitesimal.Results Both groups can maintain circulation and respiratorysystem stabile.The rate of hemodynamics(SPo2<93%)after anesthesia induction were 6% and 0 in group MS and MKS respectively.The effective concentrations in 50% patient of midazolam for skin incision(EC50i) wasl66.99ng/ml in group MS and 63.25ng/ml in group MKS.After induction,the BIS values of both groups were lower than those in preoperation(p<0.01) , and LF, LF/HF, TP decreased significantly from 540.80 ± 182.12, 3.32 ± 1.58, 1399.02 ± 359.03 to260.41 ± 102.30, 1.93± 0.80, 1029.04 ± 206.01 respectively compared with before in group MS ,HF was not changed markedly (from 181.51 ± 103.01 to 161.44 ± 77.50).In group MKS the values of HRV decreased also,but lower than those in group MS.Within each group , when the values of BIS were between 35-45,the incidence of movement occurring was lower than 20 percent.Conclusion Target-controlled infusion midazolam alone ormidazolam with ketamine during sacrul block offers satisfactory anesthesia for children.The circulation maintains stabile and respiratory depression rarely occurs.Ketamine may markedly reduced the EC₅0 of midazolam.BIS seemed to be a useful predictor of patient movement during surgery. HRV may be respond the changes of the sympathetic nerve system and the degree of analgesia during surgery indirectly.