EFFECT OF LOCAL EPINEPHRINE ON CUTANEOUS BLOODFLOW IN THE HUMAN NECK

The effectiveness of local anesthetics is improved by the addition of a vasoconstrictor which increases duration of action and decreases bot h systemic toxic reactions and local bleeding. Epinephrine, the standa rd drug for vasoconstriction, has some Limitations due to potential do se-related cardiac and local toxic effects. The authors examined the m inimal effective epinephrine concentration required for maximal cutane ous vasoconstriction in the human subject so as to limit potential dos e-related side effects, Ln a randomized, double-blinded prospective st udy, 23 patients undergoing head and neck surgical procedures under ge neral anesthesia were enrolled to quantify the effect of subdermal inf iltration of 1% lidocaine with epinephrine at varying concentrations o n local cutaneous bloodflow utilizing laser Doppler flowmetry, A compa rison of the onset of vasoconstriction and magnitude of diminished blo odflow was made for several commonly used concentrations of epinephrin e, with 1% lidocaine and normal saline serving as controls. There were no significant differences (P>.05) between epinephrine concentrations of 1:400,000, 1:200,000, 1:100,000, and 1:50,000 when examining onset and magnitude of vasoconstriction.