Rocuronium potency and recovery characteristics during steady-state desflurane, sevoflurane, isoflurane or propofol anaesthesia

We have studied the potency and recovery characteristics of rocuroniumduring 1.25 MAC of isoflurane, desflurane, sevoflurane or propofolanaesthesia in 84 patients using electromyography. Potency was determinedby a cumulative bolus technique. The mean ED50 of rocuronium was 169 (SD41), 126 (32), 121 (28) and 136 (25) micrograms kg-1 during propofol,isoflurane, sevoflurane and desflurane anaesthesia, respectively (ns), andED90 values were 358 (62), 288 (29), 289 (28) and 250 (28) micrograms kg-1,respectively. The reduction in ED90 was statistically significant for allthree inhalation anaesthetics (P < 0.05) compared with propofol. After120 min, the cumulative infusion rate of rocuronium to obtain twitchdepression of 90-95% was 9.0 (1.9), 6.3 (1.6), 6.1 (2.0) and 6.1 (1.1)micrograms kg-1 min-1 during propofol, isoflurane, sevoflurane anddesflurane anaesthesia, respectively (P < 0.01). Recovery index was 22(13), 27 (10), 28 (13) and 26 (14) min under propofol, isoflurane,sevoflurane and desflurane anaesthesia, respectively (ns). There were nosignificant differences between the three potent inhalation anaesthetics inrelation to potency, infusion requirements or recovery characteristics ofrocuronium.