1 x ED90 dose of rocuronium bromide: tracheal intubation conditions and time-course of action.

The intubation conditions and time-course of action of a 0.3 mg kg-1 bolus of rocuronium were studied under alfentanil/propofol and fentanyl/thiopentone/enflurane anaesthesia. Forty healthy patients were randomly allocated to induction of anaesthesia with either alfentanil 20 micrograms kg-1 and propofol 2.0-2.5 mg kg-1, or fentanyl 3 micrograms kg-1 and thiopentone 4-6 mg kg-1. Approximately 5 min later, after calibration of mechanomyography, an i.v. bolus of 0.3 mg kg-1 rocuronium was administered. Laryngoscopy and tracheal intubation were attempted when maximum block occurred. Intubation was completed successfully in 39 patients. The passage of the tube was rated good or excellent in 18/20 (alfentanil/propofol group) and 18/19 patients in the other group. The times of onset were 65 s and 69 s, respectively. It is concluded that a 1 x ED90 dose of rocuronium will rapidly provide good or excellent intubation conditions in the majority of cases.