Effect of nitrous oxide on the cardiovascular system and coronary circulation of the dog.

A comparison was made in seven dogs anaesthetized with pentobarbitone of cardiovascular measurements during ventilation with 65-70% nitrous oxide in oxygen and ventilation with 65-70% nitrogen in oxygen. The substitution of nitrous oxide for nitrogen was found to be associated, after 15 min, with a significant decrease in cardiac output and significant increases in right atrial and left ventricular end-diastolic pressure and systemic vascular resistance. There was no significant change in mean coronary artery flow, coronary vascular resistance or myocardial oxygen consumption.