Evaluation of twitch responses obtained from abductor hallucis muscle as a monitor of neuromuscular blockade: Comparison with the results from adductor pollicis muscle.

The twitch responses evoked from the abductor hallucis muscle (AHM) and the adductor pollicis muscle (APM) were examined simultaneously in 20 anesthetized patients following a single bolus intravenous administration of 0.04 mg·kg-1 of vecuronium bromide. The mean onset time of vecuronium-induced depression of AHM twitch responses was significantly slower than that of APM twitch responses (4.9±1.5 minvs 3.7±1.2 min, mean±SD,P<0.001), and when the clinical duration times of vecuronium were compared, AHM twitch responses recovered more quickly than APM twitch responses (15.3±4.1 minvs 19.6±6.7 min,P<0.01), although there was no statistically significant difference in the spontaneous recovery time between AHM and APM (9.8±2.9 minvs 10.0±3.6 min). It is concluded that the twitch responses of AHM may be a useful monitor of neuromuscular blockade in anesthetized patients in whom setting the blockade monitor on the patient's arms is difficult, although monitoring of twitch response of AHM is less sensitive than that of APM in case of vecuronium administration.