Clinical pharmacology of cisatracurium during nitrous oxide-propofol anesthesia in children

Study ObjectiveTo describe, in pediatric patients, the effects of three doses of cisatracurium during nitrous oxide–propofol anesthesia and to determine if larger doses result in faster onset time.SettingCollege hospital.Subjects75 ASA physical status I and II children, aged 15 to 60 months, undergoing surgery for hypospadias or undescendent testis.InterventionsPatients were randomly assigned to one of three groups according to the dose of cisatracurium: Group A = 0.1 mg/kg (two × effective dose), Group B = 0.15 mg/kg (three × effective dose), and Group C = 0.2 mg/kg (4 × effective dose).MeasurementsNeuromuscular block was assessed with TOF-Guard (Biometer International, Odense, Denmark) accelerometry. Onset time (from cisatracurium injection to maximal depression of time to first twitch), duration of peak effect (time from cisatracurium injection to 5% recovery of time to first twitch), duration of clinical action (time from cisatracurium injection to 25% recovery of time to first twitch), and recovery index (recovery of time to first twitch from 25% to 75%) were recorded.Main ResultsCisatracurium had no effect on heart rate or blood pressure at any dose. Compared with Group A, onset times in Groups B and C were shorter; and durations of peak effect and clinical action in Groups B and C were longer (P < 0.01) than those in Group A. There was no difference in recovery index among the three groups. There was no difference in onset times between Groups B and C. Compared with Group B, durations of peak effect and clinical action in Group C were longer (P < 0.05 or P < 0.01).ConclusionFour times the effective dose of cisatracurium did not significantly shorten onset time beyond that produced with three times the effective dose in young children.