Abstract: Abstract Objective: Compare the effects of cisatracurium at room temperature on the course of neuromuscular blockade. Methods Sixty patients undergoing elective abdominal surgery with general anesthesia were randomly assigned to one of four groups (n=15 each). In group Ⅰ, cisatracurium was kept in room temperature(22~24℃）for 4 hours.In group Ⅱ, cisatracurium was diluted two times with 0.9%sodium chloride，then it was kept in room temperature for 4 hours.In group Ⅲ, cisatracurium was kept in room temperature for 12 hours.In group Ⅳ（control group）, cisatracurium was kept in fridge at 2~8℃ before using. Anesthesia was induced with midazolam 0.05mg/kg, fentanyl 1~2μg/kg and propofol 1.5~2mg/kg intravenously. Laryngeal mask was inserted after cisatracurium 0.15 mg/ kg . Anesthesia was maintained with propofol 6~10mg/（kg．h）. Neuromuscular function was assessed by accelerography. TOF stimulation of ulnar nerve was used. The onset time,recovery of first twitch(T1) and recovery of TOF 25% were recorded. Results There was no significant difference in onset time,recovery of first twitch and recovery of TOF 25% between group Ⅰ and control group. In group Ⅱ and group Ⅲ, recovery of first twitch(T1) and recovery of T4/T1 25% were significantly shoter than control group and group Ⅰrespectively. Conclusion Cisatracurium was kept in room temperature for 4h,which has little effects on the course of neuromuscular blockade. However, the clinical duration of cisatracurium was siginificantly shorter when it was kept in room temperature for 12h or when it was diluted two times with 0.9%sodium chloride and then kept in room temperature for 4h.

Key words: Cisatracurium, Neuromuscular block, Hofmann elimination