The Effect of Lidocaine on the Onset Time of Atracurium

Kim, Tae Yop

Abstract

BACKGROUND: Local anesthetics for attenuating sympathetic response have been shown to interact with neuromuscular blockers. Most local anesthetics decrease neuromuscular transmission and potentiate neuromuscular blocks of muscle relaxants. The purpose of this study was to examine the effectiveness of lidocaine on the onset time of atracurium and to compare it with that of uccinylcholine.
METHODS
Fifty four patients, ASA physical status I or II, were induced with thiopental (4.0 mg/kg) and maintained with O2 -Enflurane (2.5 vol%). After controlled respiration for 3 minutes, muscle relaxants were given. They were randomly divided into three groups: Atracurium (0.5 mg/kg) was administered intravenously for 1 minute in Group A (n = 18), additional lidocaine (1.0 mg/kg) was given intravenously 1 minute prior to the administration of atracurium in Group L (n = 18), and succinylcholine (1.0 mg/kg) was given in Group S (n = 18). Neuromuscular blockade was assessed by train-of-four (TOF) at the adductor pollicis muscle with supramaximal stimulation of the ulnar nerve (2 Hz, 0.2 msec) every 12 seconds. Endotracheal intubation was performed and intubatin g conditions were evaluated according to the standard scoring method after measuring the onset time (from the end of giving muscle relaxants to the 90 % suppression of the first twitch).
RESULTS
The onset time of Group L (116.7 13.2 sec) was shorter than that of Group A (154.2 16.1 sec) (P <0.05), but was not as fast as that of Group S (42.5 5.8 sec) (P <0.05). Intubating conditions were good or excellent in all groups.
CONCLUSIONS
Additional lidocaine (1.0 mg/kg) for attenuating sympathetic response can accelerate the onset of atracurium in rapid tracheal intubation.