The Cardiovascular Effects of Nitrous Oxide During Halothane Anesthesia in the Dog

Abstract

Nitrous oxide-oxygen, halothane -oxygen, and nitrous oxide-oxygen-halothane were administered in random order to each of 12 dogs. Thirteen cardiovascular parameters-cardiac output, stroke volume, heart rate, mean arterial pressure, systolic arterial pressure, total peripheral resistance, mean transit time, left ventricular pressure, right ventricular pressure, the time derivatives of the pressures, and the left ventricular ejection time-were plotted against concentrations of nitrous oxide and halothane. Except for a greater decrease in systemic pressure and resistance with halothane-oxygen anesthesia, there was no significant difference between the performance of the cardiovascular system with halothane-oxygen and nitrous oxide-halothane-oxygen anesthesia. Since considerably greater analgesia was achieved when nitrous oxide was added to a given concentration of halothane, nitrous oxide used with halothane spares the cardiovascular system, in a relative way.