Muscle relaxation produced by rocuronium given by different methods of administration in patients undergoing abdominal surgery

Objective To compare the muscle relaxation produced by rocuronium given by target- controlled infusion (TCI),continuous infusion (CI) or intermittent,iv.bolus injection (IBI) during abdominal surgery.Methods Forty-five ASAⅠorⅡpatients undergoing abdominal surgery under general anesthesia were randomly divided into 3 groups (n=15 each):groupⅠTCI;groupⅡCI and groupⅢIBI.Neuromuscular transmission was monitored by recording the force of contraction of adductor pollicis of the left hand to supramaximal TOF stimulation of the ulnar nerve using accelerography (TOF-WATCH SX).In groupⅠrocttronium was given by a TCI system incorporating Stanpump software connected to a Graseby 3500 intravenous infusion pump.The effect site concentration was set at 3μg·ml~(-1) for intubation followed by inereament or decreament of 0.1μg·ml~(-1) to maintain T_1 at 5% of the control height while in groupⅡthe initial infusion rate was set at 600μg·kg~(-1)·h~(-1) followed after intubation by increament or deereament of 10%-20% of intubating dose every 5 minutes.In group m a bolus of 0.6 mg·kg~(-1) was given to facilitate intubation followed by intermittent iv boluses of 0.15 mg·kg~(-1). Resets During maintenance of anesthesia T_1 could be maintained at 5% of the control height in group TCI and CI but not in group IBI.The amount of rocuronium used to facilitate intubation during induction of anesthesia was significantly larger in group TCI than in group CI and IBI (P＜0.05).But there was no significant difference in the amount of rocuronium consumed during maintenance of anesthesia among the 3 groups.The onset time was significantly longer in group TCI than in group CI and IBI.The time for T_1 to recover from 5% to 25% was significantly longer in group IBI than in group TCI and CI,while spontaneous recovery indices were similar among the 3 groups.Conclusions Rocuronium given by TCI is not suitable for induction of anesthesia because of longer onset time but is the method of choice during maintenance of anesthesia because stable muscle relaxation can be achieved with faster recovery after termination.