[Evaluation of the timing principle with small priming doses of vecuronium]

The intubating conditions using the timing principle combined with small priming doses of vecuronium were evaluated in forty patients who underwent elective surgery. They were randomly assigned to one of two groups: 1) timing, 2) timing with priming. In timing group, vecuronium 0.15 mg.kg-1 was administered, and at the onset of clinical muscle weakness, thiopental 4-5 mg.kg-1 was given promptly. Sixty seconds after thiopental, patients were intubated. In the timing with priming group, vecuronium 0.005 mg.kg-1 was administered as priming doses. Four minutes later vecuronium 0.15 mg.kg-1 was given. The administration of thiopental and the intubation were done in the same way as in timing group. The time to onset of clinical weakness after the administration of vecuronium 0.15 mg.kg-1 was significantly shorter in the timing with priming group than that in the timing group (46.1 +/- 4.8 vs. 57.6 +/- 7.8, P < 0.01). There were no significant differences in intubating score, T1, TR, onset time, and duration between the two groups. We conclude that the timing principle combined with small priming doses of vecuronium might be safe and useful for rapid tracheal intubation.