Most local anesthetics decrease neuromuscular transmission and potentiate the neuromuscular blocks of muscle relaxants. The purpose of this study was to examine the influence of lidocaine on it effects rocuronium onset and intubation conditions in rapid-sequence intubation and to compare with those of succinylcholine.

Seventy five ASA physical status 1 and 2 patients were randomly allocated to three groups. Group S received succinylcholine (1.0 mg/kg), Group R received rocuronium (0.6 mg/kg) and additional lidocaine (1.5 mg/kg) was given intravenously prior to the administration of rocuronium 0.6 mg/kg in Group RL. Anesthesia was induced with midazolam 0.03 mg/kg, fentanyl 2µg/kg, and thiopental 5 mg/kg. Intubation was performed 60 seconds after the administration of muscle relaxants and intubation conditions were evaluated. Neuromuscular blockades were assessed by single twitch responses of the adductor pollicis after ulnar nerve stimulation by accelerography (0.1 Hz, 0.2 ms supramaximal stimuli).

The onset time of Group S (47.8±11.3) was shorter than those of Group R (87.8±30.2) and Group RL (75.4±21.5), but no differences was observed between the onset times of Group R and Group RL. Intubation conditions were good or excellent in all groups.

Additional lidocaine to rocuronium neither influences intubation condition nor accelerate the rocuronium onset, and it is cannot be viewed as an alternative for succinylcholine in rapid-sequence tracheal intubation.