Comparison of butorphanol or midazolam alone and combination of the two drugs in preventing etomidate-induced myoclonus during anesthesia induction / 中华麻醉学杂志

ABSTRACT

Objective To compare butorphanol or midazolam alone and combination of the two drugs in preventing etomidate-induced myoclonus during anesthesia induction.Methods One hundred sixty patients, aged 40-64 yr, with body mass index of 20-25 kg/m2, of American Society of Anesthesiologists physical status Ⅰ or Ⅱ , scheduled for elective operations under general anesthesia, were randomly allocated into 4 groups with 40 patients in each group control group (group C), butorphanol group (group B) , midazolam group (group M) , and butorphanol combined with midazolam group (group BM).Before induction of anesthesia, butorphanol 15.0 μg/kg, midazolam 50 μg/kg, and butorphanol 7.5 μg/kg combined with midazolam 25 μg/kg were injected intravenously over 30 s in B, M and BM groups, respectively.The equal volume of normal saline was given in group C.And 2 min later, etomidate 0.3 mg/kg was injected intravenously over 1 min.The occurrence of myoclonus was recorded within 2 min after administration of etomidate, and the severity of myoclonus was assessed.Results Compared with group C, the incidence and severity of myoclonus were significantly decreased in B, M and BM groups (P＜0.05).Compared with B and M groups, the incidence and severity of myoclonus were significantly decreased in group BM (P＜0.05).There was no significant difference in the incidence and severity of myoclonus between group B and group M (P ＞ 0.05).Conclusion Butorphanol or midazolam alone produces similar efficacy in preventing etomidate-induced myoclonus during anesthesia induction, and the combination of the two drugs provides better efficacy than either alone in the patients.