Effect of biliary obstruction on muscle relaxation with vecuronium.

Vecuronium bromide was used as a muscle relaxant in 30 patients undergoing biliary surgery. Ten patients had biliary obstruction, 10 patients without biliary obstruction were elderly (78 +/- 1.2 yrs; mean +/- SEM) and 10 patients without biliary obstruction were young or middle-aged (35 +/- 3.0 yrs). The muscle response to ulnar nerve stimulation was measured electromyographically. The results indicate that the neuromuscular blocking effect of vecuronium is significantly prolonged in patients with biliary obstruction. The mean total dose of vecuronium was lower in the patients with biliary obstruction (1.2 +/- 0.1 micrograms kg-1 min-1) than in the elderly patients (1.7 +/- 0.2 micrograms kg-1 min-1) and young patients (2.0 +/- 0.2 micrograms kg-1 min-1; P less than 0.05). There were no statistically significant differences in the distribution half-lives or in the distribution volumes of vecuronium between the groups.