EFFECT OF PRIOR ADMINISTRATION OF SUCCINYLCHOLINE ON DURATION OF ACTION OF VECURONIUM DURING ENFLURANE ANESTHESIA

The effects of succinylcholine, which,vas given to facilitate tracheal intubation on the duration of action of subsequently administered vec uronium bromide, were evaluated in 54 adult patients who underwent abd ominal surgeries under enflurane anaesthesia. The electromyographic re sponse to train-of-four ulnar nerve stimulation was measured. Twenty-s even patients received 1 mg.kg(-1) of succinylcholine, followed by 0.1 5 mg.kg(-1) of vecuronium when the electromyographic response recovere d to 50% of control after succinylcholine-induced neuromuscular blocka de. The other 27 patients served as the control group, receiving 0.15 mg.kg(-1) of vecuronium without prior administration of succinylcholin e. In both groups, administration of supplemental 0.04 mg.kg(-1) of ve curonium was repeated whenever the electromyographic response recovere d to 25% of control during surgical procedures. The duration of blocka de induced by the initial 0.15 mg.kg(-1) of vecuronium was 56.5 +/- 12 .8 (mean +/- s.d.) min for the group with succinylcholine, and 58.5 +/ - 21.5 min for the control group. In both groups, the average duration of four consecutive supplemental doses of vecuronium was approximatel y 35 min. No significant differences between groups were found in the duration of neuromuscular blockade induced by initial and supplemental doses of vecuronium.