BACKGROUND: Rocuronium produces various withdrawal responses if administered after loss of consciousness. We investgated the incidence of withdrawal response after injecting rocuronium in female and male patients, and also evaluated the effect of injecting rocuronium at room and low temperature (4-5℃).

METHODS: We evaluated 240 in-patients undergoing various elective general surgeries. Patients were randomized into two groups of 120 patients in a blinded, prospective study; group I (rocuronium was stored at ambient temperature [20-24℃], n = 120 [60 male patients, 60 female patients]), group II (rocuronium was stored in a refrigerator [4-5℃], n = 120 [60 male patients, 60 female patients]). Ten seconds after the induction of anesthesia with 5 mg/kg of thiopentothal sodium, rocuronium 0.6 mg/kg was injected over 10 seconds using on intravenous cannula. Patient's response on injecting rocuronium was graded using a four-point scale.

RESULTS: The incidence of withdrawal response was 29.2% (female 31.7%, male 26.7%) in group I and 31.7% (female 31.7%, male 31.7%) in group II. Moderate to severe movement was 18.4% (female 20%, male 16.7%) in group I and 142% (female 15%, male 13.2%) in group II.

CONCLUSIONS: The incidence and the degree of withdrawal response on injecting rocuronium were no different in groups I or II, or between males and females.