RESUMO
Objective To compare pharmacodynamics of rocuronium in neonates,infants,young children and children.Methods One hundred and sixty ASA Ⅰ or Ⅱ pediatric patients undergoing elective surgicalprocedures under total intravenous anesthesia(TIVA)were divided into 4 groups according to ages(n=40 each):neonate group(0-28d),infant group(28 d<age 12 months),young children group(1 yr<age≤3 yr)and children group(3 yr<age≤10 yr).Twenty patients Were randomly selected from each group,and rocuronium was administered iv by using cumulative dose-response technique at four doses(an initial dose of 40 μg/kg, 80 μg/kg,120μg/kg and 120μg/kg in neonate,infant,young children and children groups respectively,and three increments of 40μg/kg each).After each administration,TOF response was observed.When T1 was stable, the next administration was given.50%,90%and 95%effective dose(ED50,ED90.ED95)were calculated by Probite method.Twenty patients were randomly selected in each group were given rocuronium 2 times of ED95.The onset time,duration of peak effect.clinical duration.total duration and recovery index were recorded.Results ED50,ED90 and ED95 of rocuronium were significantly higher in young children and children groups than in neonate group(P<0.01),but there there was significant difference in the indices mentioned above between infant and neonate group(P>0.05).Onset time of muscle relaxation.clinical duration and total duration were significantly shorter and recovery index lower in the other 3 groups than in neonate group(P<0.01).but there was nosignificant difference in the duration of peak effect among the 4 groups(P>0.05).ED50,ED90 and ED95 of rocuronium were significantly higher in children group than in young children group(P<0.01).Conclusions There are significant differences in dose-effect and time-effect relationships among different age children and neonate is more sensitive to rocuronium than the other age children.