[Monitoring atracurium neuromuscular block: comparison of single twitch and train of four].

Onset time and duration of action were monitored in three groups of 13 patients each, using different patterns of neuromuscular stimulation (single twitch stimulation, STS at 10 sec intervals and train of four, TOF, at 10, and 20 sec intervals) to assess: 1) the correspondence between the single twitch and the first TOF twitch; 2) the importance of the stimulation interval. The results show that onset time is longer and the duration of action is shorter when STS or TOF is used at 20 sec intervals in comparison to TOF at 10 sec intervals.