Effect Of Sevoflurane On Muscle Relaxation Produced By Rocuronium

Background Rocuronium is a new non-depolarizing neuromuscular blocking agent with the shortest onset time and intermediate duration of action and cardiovascular stability in the clinical use. The studies of midazolam, fentanyl, etomidate, propofol have no effects on the neuromuscular block effect of rocuronium and inhalation of enflurane, isoflurane, deflurane can augment the effect of rocuronium. but various concentration of sevoflurane have effects on the various doses of rocuronium, which has not be found in the published papers, so the objective of the study is to observe 1 MAC and 1.3 MAC sevoflurane have effects on the rocuronium 2ED95(0.6 mg·kg-1)and 3ED95(0.9mg·kg-1) given to contribute to the useage of the clinic.Objective To evaluate the potentiation effect of sevoflurane on neuromuscular block of rocuronium.Methods Ninety ASAⅠorⅡpatients, aged 18-65 yr, undergoing selective surgery under general anesthesia were studied, without neuromuscular disease, liver or kidney disease and receiving any drug which may affect neuromuscular transmission. All patients were randomly divided into six groups (n=15). A bolus of rocuronium 0.6 mg·kg-1 and 0.9 mg·kg-1 was given during maintenance of anesthesia groups (Ⅰa ndⅡ), inhalation of 5% sevoflureane until to the stable end-tidal concentrations of sevoflurane at the 1 MAC groups (Ⅲa ndⅣ) and 1.3 MAC groups (ⅤandⅥ) to maintain anesthesia respectively. A bolus of rocuronium 0.6 mg·kg-1 and 0.9 mg·kg-1 was given intraveneously in groups (ⅢandⅣ) and (Ⅴa ndⅥ) following stable anesthesia respectively. The onset times and degrees of neuronmuscular blockade were monitored with train-of-four (TOF) technique. Results The onset times of groupsⅤa ndⅥwere shorter than those of groupsⅠa ndⅡrespectively (P<0.05), but between in groupsⅢandⅣthey were no differences in groupsⅠa ndⅡ; the clinical duration of action (duration of TOF=0) , the times of T1 recovery to 25%,50% and 75% of baseline and recovery index in groupsⅢa ndⅤ, groupsⅣandⅥwere prolonged than those in groupsⅠandⅡrespectively(P<0.05); especially, in groupsⅤandⅥwere significantly prolonged than those in groupsⅠa ndⅡrespectively(P<0.01); but in groupsⅡa ndⅢ,Ⅳa ndⅤthere were no significant differences in the above parameters .Conclusion Sevoflurane can enhance the neuromuscular block effect of rocuronium, the dose of rocuronium shoud be reduced when it is used with sevoflurane. The high end-tidal concentration of 1.3 MAC sevoflurane is given, the good effects of rocuronium could be induced through shortening the onset time, and prolonging the action time and the restoration times.