The Effect of Succinylcholine on the Duration of Action of Pancuronium

Kim, Hyeun; Yoon, Myung Ha; Im, Woong Mo

Abstract

For the assessment of the effect of succinylcholine(SCh) on pancuronium, 62 adult patients undergoing elective surgery under gerieral anesthesia were subjected tc this study in which the EMG response(twitch hight) of the hand to TOF stimulation(0.2 Hz) of ulnar nerve was monitored and recorded with Datex Relaxograph. According to the amount and mode of the drugs administered, the patients were divided into four experimental groups: 1) Group I, a bolus intravenous injection of pancuronium in dose of 0.05 mg/kg. 2) Group II, intravenous injection of pancuronium 0.1 mg/kg, a double dose of group I. 3) Group III, intravenous injection of pancuronium(0.05 mg/kg) after 25 to 50 recovery of initial twitch height from twitch height depression induced by SCh(1 mg/kg). 4) Group IV, mixed intravenous injection of SCh(1 mg/kg) and pancuronium(0.05 mg/kg). Followings were the results. 1) Mean onset time of the effect of pancuronium, was 15.6+/-1.1 minutes in group I and 13.8+/-1.5 minutes in group II, to 2,9+/-0.4 and 1.3+/-0.1 minutes in group III and IV respectively, and decreased(p< 0.001). 2) Duration of action of pancuronium was 47.1+/-4.5 minutes in group I and 87.7+/-7.4 minutes in group II, the prolongation of the latter being significantg<0.001). It was, however 48.3+/-5.2 minutes in group III, indicating that SCh showed a little effect, while it was 21.2+/-1.9 minutes in group IV, being significantly shorter than those of group I and III(p<0.001), 3) Potency of pancuronium expressed by the percentage changes of initial twich height was 34.3+/-6.0% in group I and it was noted to decrease significantly to 4.0+/-1.0% in group II and 0% in group IV(p<0.001). This pattern of decrease was almost similar to group II. 4) Presence of pancuronium(0.05 mg/kg) in group IV did not have any effect on the intensity of fasciculation induced by SCh. These results indicate that succinylcholine could potentiate the onset time and action potency of pancuronium by facilitating quick action on the receptor, but it have an antagonistic effect on the duration of action of pancuronium.