[Potentiation of pancuronium induced neuromuscular blockade by nitrous oxide]

To evaluate in man the potentiation by nitrous oxide of the neuromuscular blockade produced by pancuronium, pancuronium 0.025, 0.035, 0.049 or 0.068 mg.kg-1 was given during thiamylal-fentanyl anesthesia with and without nitrous oxide, and the evoked electromyography (EMG) of hypothenar muscle was measured. In the group receiving nitrous oxide the ED50 and ED95 were 0.0359 and 0.0691 mg.kg-1. In the group not receiving nitrous oxide, these values were 0.0389 and 0.0849 mg.kg-1. The dose-response curve (DRC) constructed from log-probit transformation for the group not receiving nitrous oxide shifted to the right for 10.3% (P < 0.05). It was also revealed that the magnitude of the blockade was influenced by dose, gender, nitrous oxide, lean body mass and body surface area by the multiple regression analysis. DRS for the female patients shifted to the left, and the differences between both sexes seemed to decrease in the group receiving nitrous oxide. It is concluded that the results of the present study appears to be similar to those obtained in the previous study on vecuronium using EMG.