Effects of sodium nitroprusside on thermal trauma depressed cardiac output in the anaesthetized dog.

Thermal trauma to the anaesthetized dog results in an immediate significant decrease in cardiac output, an increase in peripheral resistance and no significant change in mean arterial blood pressure. The infusion of sodium nitroprusside, 5 or 8 micrograms/kg X min, produced a significant increase in cardiac output and a decrease in peripheral resistance. Mean arterial blood pressure fell during the infusion and returned to pre-injection values immediately upon cessation of infusion. Cardiac output and peripheral resistance also returned to pre-infusion values upon cessation of infusion. A comparison between the responses to infusion of sodium nitroprusside and the administration of verapamil showed that infusion of sodium nitroprusside produced a slower onset of increase in cardiac output and a lower maximum increase in cardiac output than observed after verapamil.