Effect of Intravenous Lidocaine on Rocuronium: A Randomized Controlled Trial.

Purpose: Under general anesthesia, lidocaine shortens the onset time of vecuronium but it does not affect that of rocuronium. We suspected that the dose of rocuronium used in previous reports, 0.6 mg/kg, was too high to detect any difference due to lidocaine's effect. We investigated the effects of 1.5 mg/kg lidocaine on the onset time, 50% depression time, 100% depression time, and duration of action of 0.4 mg/kg rocuronium.

Methods: Sixty adult patients who underwent elective operation under general anesthesia without tracheal intubation were randomly divided into two groups: including a lidocaine group (LG) and a placebo group (PG). Anesthesia was induced and maintained using propofol and remifentanil. After the loss of consciousness, a supraglottic device was inserted. After the neuromuscular monitor was calibrated, measurements were initiated with train-of-four stimulation at 20-second intervals, and 1.5 mg/kg lidocaine and the same volume of physiological saline were administered to the LG and the PG respectively. Ten seconds after the next train-of-four stimulation, 0.4 mg/kg rocuronium was administered.

Results: The mean (standard deviation) onset time (seconds) between the LG and PG were 368.0 (170.5) and 314.8 (161.1), respectively, with no significant difference ( = 0.24). There were no significant differences between the groups in terms of the 50% depression time ( = 0.71), 100% depression time ( = 0.53), or duration of action ( = 0.45).

Conclusion: The pre-administration of 1.5 mg/kg lidocaine did not affect the onset time, 50% depression time, 100% depression time, or duration of action of 0.4 mg/kg rocuronium.