The Effect Of Dexmedetomidine On The Median Effective Concentration (EC₅₀) Of Sufentanil For Respiratory Depression

Objective To determine the effect of dexmedetomidine on the median effective concentration (EC50) of sufentanil for respiratory depression.Methods ASA I or II patients of both sexes aged20-50years with a body weight index of20-25undergoing selective thyroid adenoma operation were randomly divided into2groups:control group(group C) and dexmedetomidine group (group D). Patients in groups D received intravenous of0.6ug/kg dexmedetomidine (diluted with normal saline) and patients in groups C received intravenous of5ml normal saline. According to sequential methods we set the target plasma concentration of sufentanil. The initial target plasma concentration of sufentanil was set at0.20ng/ml and decreased/increased by20%in the next patient. Effective concentration (EC50) of sufentanil for respiratory depression and95%confidence interval (CI) were calculated with sequential methods.Results EC50of sufentanil in group D wasO.1770ng/ml(95%CI0.1638-0.1902ng/ml) and0.2080ng/ml(95%CI0.1950-0.2210ng/0.1950-0.2210ml)in group C,and was significantly lower in group D than in group C.Conclusion Dexmedetomidine0.6ug/kg infused iv before opration can reduce the effective concentration (EC50) of sufentanil for respiratory depression...