MAINTENANCE OF CONSTANT 95% NEUROMUSCULAR BLOCKADE BY ADJUSTABLE INFUSION RATES OF PANCURONIUM AND ATRACURIUM

In a double-blind study, 39 patients (ASA groups I-II) were given either pancuronium or atracurium as an infusion during surgery. The drugs were given as an initial loading dose of 0.064 mg kg −1 or 0.30 mg kg −1 , respectively, followed by an infusion, the rate of which was regulated to produce a constant 95% depression of the evoked twitch response throughout surgery. No significant difference in the number of corrections of the infusion rate per hour was found (4.6 v . 4.9). Mean infusion maintenance doses were 35 and 356 μg kg −1 h −1 respectively. The inter-individual variability of maintenance doses for the two drugs did not differ, the coefficients of variation being 0.32 and 0.24. On stopping the infusion, the patients given atracurium recovered to a 15% twitch faster than those given pancuronium. In addition neostig-mine produced a quicker recovery in this group. Thus atracurium may be a more satisfactory drug for use by infusion.