Circulatory and catecholamine responses to tracheal intubation and skin incision during sevoflurane, isoflurane, or halothane anesthesia

The anesthetic suppression of responses to noxious stimuli might reflect a summation of the suppression of the basal functions and the response capability. We investigated the basal suppression and response capability in hemodynamics and plasma catecholamine levels with different anesthetics at the same minimum alveolar concentration (MAC) level. Fifty-four patients were allocated to one of 6 groups to receive sevoflurane, isoflurane, or halothane at 1.25 or 2.0 MAC. Anesthesia was induced with the test agent in oxygen and the end-tidal concentration of the agent was maintained for at least 15 min at 1.25 or 2.0 MAC. The trachea was intubated under muscle relaxation with 0.1 mg·kg⁻¹ vecuronium. Skin incisions were made after maintaining the end-tidal concentration of the agent for at least 15 min after tracheal intubation. The mean arterial pressure, heart rate, rate-pressure product, and plasma levels of noradrenaline and adrenaline at the prestimuli period showed no difference between agents at each MAC. The rises in these variables by tracheal intubation and skin incision were greatest in the sevoflurane group, least in the halothane group, and intermediate in the isoflurane group. Although basal hemodynamic suppression is similar at the same MAC, the suppressive action of sevoflurane on the circulatory response capability to noxious stimuli is weaker than that of isoflurane and halothane. This study was presented in part at the 42nd annual congress of the Japan Society of Anesthesiology, April 20, 1995