Does ventilation with nitrous oxide affect myocardial blood flow and oxygen metabolism in dogs?
In a canine model, normoxic nitrous oxide anesthesia increases coronary blood flow by decreasing coronary vascular resistance.
The effects of ventilation with nitrous oxide in oxygen on myocardial blood flow and oxygen metabolism were investigated in 31 mongrel dogs. The results of this study showed that, compared with controls, hyperoxic nitrous oxide mixtures did not cause any great changes in myocardial haemodynamics, despite a decrease in cardiac output and an increase in systemic vascular resistance. Normoxic nitrous oxide mixtures produced an increase of the coronary blood flow due to decreased coronary vascular resistance. To what extent this coronary vasodilatation resulted from an increased myocardial metabolism or from a direct effect of nitrous oxide on the coronary vascular bed cannot be quantified from the present results.
Dottori et al. (Sun,) studied this question.