Effects of Intravenous Administration of Local Anesthetics on Systemic and Pulmonary Hemodynamics During Nitrous Oxide-Halothane Anesthesia in the Dog

Abstract

The effects of an intravenous bolus injection of subseizure doses of lidocaine and bupivacaine on the systemic and pulmonary circulation were studied in dogs anesthetized with nitrous oxide (N2O)-halothane. The administration of high concentrations of halothane (1-1.5%) with N2O produced a marked decrease in mean arterial pressure and cardiac output; a low concentration of halothane (0.5%) caused less cardiovascular depression. Mean pulmonary arterial pressure (MPAP) did not change after the intravenous administration of 10 mg/kg of lidocaine or 2.5 mg/kg of bupivacaine during N2O-halothane (0.5-1.5%) anesthesia. These results indicate that an intravenous injection of subseizure doses of local anesthetics produces a marked cardiovascular depression and a slight change in MPAP during N2O-halothane (1-1.5%) anesthesia in contrast to N2O anesthesia.