Comparison between the continuous infusion of vecuronium and the intermittent administration of pancuronium and vecuronium.

The neuromuscular blocking effects of repeated bolus injections of pancuronium, or vecuronium, and of the continuous infusion of vecuronium have been compared in 36 patients by means of evoked twitch tension. Groups I and II received a loading dose (0.075 mg kg-1) of pancuronium or vecuronium, respectively, followed by 0.015-mg kg-1 maintenance doses when twitch tension had recovered to 25% of control. Group III received a 0.075-mg kg-1 loading dose of vecuronium plus a continuous infusion (commenced simultaneously) delivering 0.075 mg kg-1 h-1. With repeated injections of pancuronium (group I) or vecuronium (group II), the durations of blockade to 25% recovery were 64 and 25 min, respectively. Maintenance doses had to be injected every 42 min with pancuronium and every 12 min with vecuronium. The recovery times from 25% to 75% of control twitch tension were 44 v. 12 min. The continuous infusion of vecuronium (group III) produced consistent neuromuscular blockade at an average level of 87% twitch depression. The times from the end of infusion to 25%, and from 25% to 75%, recovery averaged 20 and 26 min, respectively. These values did not correlate with the total dose of vecuronium infused. For clinical practice, the suggested loading dose is 1.5 times the ED90 (= 0.07 mg kg-1) followed by an infusion of the same dose per hour. The infusion should be started within 10 min of the injection of the loading dose.