Effects of intravenous or endotracheal lidocaine on circulatory changes during recovery from general anesthesia.

Intravenous lidocaine (1.5 mg.kg(-1)) was not effective in attenuating the circulatory changes and the cough reflex induced by airway stimulation during recovery from general anesthesia, whereas endotracheal 4% lidocaine (3 ml) was effective. The arterial concentration of the intravenously administered-lidocaine peaked at a level of 9.52 +/- 0.81 microg.ml(-1) 0.5 min later. The arterial concentration of the endotracheally administered-lidocaine peaked at 1.44 +/- 0.13 microg.ml(-1) 15 min later. These findings indicate that the endotracheal administration of lidocaine may be superior to the intravenous administration for attenuating the circulatory changes and the cough reflex during recovery from general anesthesia, and that the arterial concentration of lidocaine did not correlate with the clinical efficacy for this purpose.