EFFECTS OF PRETREATMENT WITH CISATRACURIUM ON SUCCINYLCHOLINE-INDUCED FASCICULATIONS AND MYALGIA

Abstract

S157 INTRODUCTION: Pretreatment with small doses of nondepolarizing muscle relaxants, particularly tubocurarine, is commonly used to prevent succinylcholine-induced side effects such as fasciculations and postoperative myalgia. The purpose of this placebo-controlled study was to compare the efficacy of cisatracurium (0.01 mg/kg) and tubocurarine (0.05 mg/kg) in prevention of succinylcholine-induced fasciculations and myalgia. METHODS: Following IRB approval and informed consent, 42 healthy outpatients undergoing peripheral surgery were randomized to receive saline (n=18), tubocurarine (n=12), or cisatracurium (n=12) two minutes prior to induction of anesthesia. Occurrence of diplopia, difficulty in swallowing, and signs of muscle weakness were noted. Anesthesia was induced with propofol (2.5 mg/kg iv) and succinylcholine (1.5 mg/kg iv) and maintained with fentanyl, isoflurane and N2 O 60% in O2. Muscle relaxation was maintained with cisatracurium 2-4 mg iv. At the end of the operation, residual neuromuscular block was antagonized with combination of neostigmine and glycopyrrolate. Fasciculations were recorded on a 4-point scale: 1=nil; 2=mild fine fasciculations of the eyes, face, neck or fingers without limb movement; 3=moderate fasciculations of greater intensity than mild that occurred at more than two sites or that produced limb movement; 4=severe vigorous, sustained, and widespread fasciculations possibly requiring forceful retention. Myalgia was scored preoperatively, in the PACU, and 24 h postoperatively using a 4-point scale: 1=absence of muscle pain; 2=mild muscle stiffness or pain, when specifically asked about in the nape of the neck, or in the shoulders and lower chest on deep breathing; 3=moderate muscle stiffness and pain spontaneously complained of by the patient that requires analgesics; 4=severe, incapacitating generalized muscle stiffness or pain. Data were analyzed using ANOVA or Kruskuall Wallis test (as appropriate), with p <0.05 considered statistically significant. RESULTS: The three groups were similar with respect to demographic and clinical data. No patient complained of diplopia or difficulty in swallowing. Significantly higher number of patients in the placebo and cisatracurium groups demonstrated moderate-to-severe fasciculations, as compared with the tubocurarine group. There was no difference in the incidence of myalgia between the groups. (Table 1)Table 1DISCUSSION: These data suggest that tubocurarine 0.05 mg/kg is more effective than cisatracurium 0.01 mg/kg in preventing succinylcholine-induced fasciculations. However, pretreatment with nondepolarizing muscle relaxants does not decrease the incidence of postoperative myalgia.