Comparison of pharmacodynamics of rocuronium administered by continuous infusion versus intermittent bolus injection

Objective The study was designed to compare the pharmacodynamics of rocuronium administered by continuous infusion and intermittent bolus injection Methods Fifty ASAⅠ Ⅱ patients without any neuromuscular disease undergoing elective surgery under general anesthesia were randomly divided into two groups of 25 patients each In groupⅠ patients received rocuronium by intermittent bolus injection and in group Ⅱ by continuous infusion The responses of adductor pollicis to train of four (TOF) stimulation of ulnar nerve were monitored The onset time, the time of maximal neuromuscular blockade, the spontaneous recovery from paralysis and the total dose of rocuronium were recorded Intravenous anesthesia was used for both induction and maintenance of anesthesia, no patient received reversal of block Neuromuscular blockade monitoring ended when TOF ratio(T 4/T 1)≥70% The patients were extubated when ventilation was satisfactory Results The two groups were comparable with regard to age, sex, weight and duration of operation The mean onset time after rocuronium bolus(0 6mg/kg) was (78 18±15 44) s In group Ⅱ the mean infusion rate was (6 31±1 93)μg·kg -1 ·min -1 which was not significantly different from the amount of rocuronium administered per minute (5 43±1 46)μg·kg -1 ·min -1 in groupⅠ The mean interval between two bolus injection in group Ⅰwas (29 24±6 26) min, and no significant difference was seen between intervals The spontaneous recovery from neuromuscular block was significantly faster in group Ⅱ than that in group Ⅰ Conclusions Rocuronium has no cumulative effect There was no significant difference in the amount of rocuronium administered per unit time between the two groups The spontaneous recovery from neuromuscular block is faster by continuous infusion than that by intermittent bolus injection