Differential effects of vecuronium on the thumb and the big toe muscles evaluated by acceleration measurement

To clarify the differential effects of vecuronium on the thumb and on the big toe, train-of-four (TOF) stimuli were applied to the ulnar nerve at the wrist and the tibial nerve at the ankle in anesthetized patients using two acceleration transducers. Ten adult patients, aged 21-55 years, were studied. Anesthesia was induced by an intravenous injection of thiopental, and vecuronium 0.1 mg·kg^-1 was used for paralysis. Anesthesia was maintained with nitrous oxide (66%)-oxygen-sevoflurane (1 MAC). The duration of time to the maximal twitch depression on the thumb and the big toe was 136.5±32.5 s and 183.0±40.1 s (P<0.05), respectively. The time to 25% recovery of the twitch height on the thumb and the big toe was 48.1±17.3 min and 39.1±11.6 min, respectively; the time to 50% recovery of twitch height on the thumb and the big toe was 54.1±16.1 min and 40.0±9.2 min (P<0.05), respectively. When paralysis was reversed at 25% of TOF ratio on the thumb, the value of the TOF ratio on the big toe was 58.5±18.2% (P<0.01).