Does continuous pentobarbital infusion provide stable cardiac electrophysiology and plasma concentrations during prolonged anesthesia in dogs?
Continuous pentobarbital infusion provides a stable experimental model for cardiac electrophysiological studies in dogs for several hours without significantly altering electrophysiological variables.
There is need for a prolonged stable level of anaesthesia, and we therefore investigated the cardiac electrophysiological effects of continuous pentobarbital infusion after initial pentobarbital injection to induce anaesthesia in dogs. Plasma concentrations of pentobarbital were measured by gas-liquid chromatography. Heart rate, atrial, atrioventricular (AV) nodal and His-Purkinje conduction times were measured by His bundle electrography, and atrial, AV nodal and ventricular refractoriness by programmed electrical stimulation. Over a 5-h observation period, continuous infusion of pentobarbital 3.5 mg X kg-1 X h-1 after an initial pentobarbital injection of 25 mg X kg-1 intravenously gave stable mean plasma concentrations of 140-135 mumol X 1(-1). The cardiac electrophysiological variables studied did not change significantly during this period. We conclude that a stable experimental model for cardiac electrophysiological studies can be obtained for several hours by continuous pentobarbital infusion.
Hotvedt et al. (Wed,) studied this question.