Vecuronium-induced neuromuscular block during xenon or sevoflurane anaesthesia in humans

Twitch response using accelerometry and plasma concentrations, of vecuronium and its metabolite were studied in 27 surgical patients during xenon or sevoflurance anaesthesia after administration of vecuronium 0.05 mg kg-1. Anaesthesia was maintained using oxygen-xenon (MAC = 71%) or oxygen-sevoflurane (MAC = 2%) at an end-tidal concentration equal to 0.8 MAC (i.e. 57% xenon and 1.6% sevoflurane). Mean time from administration of vecuronium to 25% recovery of the first twitch of the train-of-four response was significantly shorter in the xenon group than in the sevoflurane group (12.9 (SD 2.5) min vs 19.4 (6.0) min, respectively). Plasma concentrations of vecuronium at 25% recovery were significantly higher during xenon than during sevoflurane anaesthesia (187 (49) ng ml-1 vs 136 (40) ng ml-1, respectively), while those of 3-desacetylvecuronium were similar in both groups.