RESUMO
The cardiovascular effects of continuous epidural administration (CEA) of lidocaine were investigated in anesthetized dogs. Loading epidural injections of 2, 4, or 6 mg/kg of lidocaine were followed by CEA with 1, 2, or 3 mg/kg/hr lidocaine, respectively, for 2 hr under 2.0% isoflurane anesthesia. Heart rate, direct blood pressure, cardiac index, and stroke volume decreased dose-dependently during CEA, whereas systemic vascular resistance did not significantly differ with dose, and no characteristic changes were observed in any groups. Plasma lidocaine concentration reached a steady state during CEA and increased in a dose-dependent manner. Circulatory suppression caused by lidocaine CEA was not attributable to peripheral vasodilation, but rather to the direct cardiac action of systemic lidocaine absorption from the peridural space.
