Effect of Additional Lidocaine on the Onset Time of Vecuronium / 대한마취과학회지

ABSTRACT

BACKGROUND: Local anesthetics have been shown to interact with neuromuscular blockers. Most local anesthetics decrease neuromuscular transmission and potentiate neuromuscular block from muscle relaxants. The purpose of this study was to examine the effectiveness of lidocaine on the onset time of vecuronium and to compare that with other method such as simply increasing the dose of vecuronium. METHODS: Sixty patients of ASA physical status I or II were induced with thiopental (4-5 mg/kg) and maintained with O2-enflurane (2.5 vol%). They were randomly divided into four groups Vecuronium (0.1 mg/kg) was administered intravenously in Group C (n = 15), additional lidocaine (1 mg/kg) was given intravenously 1 min prior to administration of vecuronium in Group L (n = 15), increased vecuronium (0.15 mg/kg) was given in Group V (n = 15) and succinylcholine was given in Group S (n = 15), respectively. Neuromuscular blockade was assessed by train-of-four (TOF) at the adductor pollicis muscle with supramaximal stimulation of ulnar nerve (2 Hz, 0.2 ms) every 12 sec. Endotracheal intubation was performed and intubating conditions were evaluated according to the standard scoring method after measuring the onset time (from the end of giving each muscle relaxants to the 90% suppression of the first twitch). RESULTS: The onset time of Group L (122.0+/-11.0 sec) and that of Group V (98.0+/-16.9 sec) were shorter than that of Group C (135.2+/-16.0 sec) (P<0.05), but these were not shorter than that of Group S (42.0+/-6.2 sec). There was no statistical difference between Group L and Group V. Intubating conditions were good or excellent in all groups. CONCLUSIONS: Additional lidocaine for attenuating sympathetic response could accelerate the onset of vecuronium. But the onset time of this method was not shorter than that of simply increasing the dose of vecuroium nor that of succinylcholine.