Abstract:

Objective To evaluate the neuromuscular blockade of different doses of mivacurium in pediatric anesthesia. Methods Sixty children with American Society of Anesthesiologists （ASA） class Ⅰor Ⅱ undergoing selective surgery were randomly allocated to groupⅠ(≤3 years old) and groupⅡ (＞3 years old). Each group was subdivided according to the initial dosage of mivacurium (0.2 mg/kg or 0.25mg/kg)(groupⅠ0.2, group Ⅱ0.2, group Ⅰ0.25 and group Ⅱ0.25，n=15). At twitch recovery to 25%, neuromuscular blockade was maintained by intermittent intravenous injection of 0.1 mg/kg mivacurium. Response of ulnar nerve to train-of-four (TOF) stimulation was monitored with TOF-Watch SX muscle relaxation monitor, and the neuromuscular blockade indexes were recorded. Results The onset time in group Ⅰ0.25 was significantly shorter than that in group Ⅰ0.2 and group Ⅱ0.25（P<0.05）, and the onset time in group Ⅱ0.25 was significantly shorter than that in group Ⅱ0.2 (P<0.05). There was no significant difference in the duration of clinical action of initial dose and repeated dose of mivacurium among groups (P>0.05). There was no difference in the recovery index and duration of TOF ratio (TOFR) recovery to 0.75 and 0.9 of the last dose of mivacurium among groups (P>0.05). Conclusion Children younger than 3 years old have shorter onset time than elder ones, and 0.25 mg/kg mivacurium may produce shorter onset time than 0.2 mg/kg mivacurium. Neuromuscular recovery is independent of age and times of additional doses.

Key words: mivacurium, intubation condition, neuromuscular blockade, children