Intravenous nitroglycerin and myocardial metabolism during anesthesia in patients undergoing myocardial revascularization.

Although intravenous nitroglycerin has been used to control the hypertensive response during sternotomy in patients undergoing myocardial revascularization, the effects of the drug on myocardial oxygen supply and demand have not been anesthetized for coronary artery bypass, were studied before and after administration of intravenous nitroglycerin (mean dose 12 microgram/kg in 6 minutes). Evaluation of myocardial metabolism showed an increase in coronary sinus oxygen content (p less than 0.05) and a reduction in myocardial oxygen consumption (p less than 0.05). Although mean myocardial lactate extraction and coronary sinus blood flow were not significantly altered in the group as a whole, variations in individual patient responses were observed and are discussed. These direct observations of global myocardial metabolism observed in this study group are similar to the conclusions reached by other investigators using indirect indices of myocardial oxygen supply and demand.