Effects of Lidocaine on the Anesthetic Requirements for Nitrous Oxide and Halothane

Abstract
The effects of various plasma concentrations of lidocaine on N2O anesthesia in man and halothane requirements in the dog were studied. The response to incision of the skin was observed in 20 patients who were anesthetized with N2O, 70% inspired, and O2, 30%, plus various plasma levels of lidocaine. Changes in the MAC [minimal anesthetic concentration] of halothane in dogs were observed at various levels of lidocaine. In both circumstances lidocaine concentrations of 3-6 .mu.g/ml decreased anesthetic requirements approximately 10-28%. At clinically common concentrations of lidocaine, significant decreases in anesthetic requirements should be anticipated.