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

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