The effect of nitroglycerin in gas exchange on chronic obstructive pulmonary disease

Nitroglycerin was administered to a group of 11 patients with chronic obstructive pulmonary disease in a dose of 0.4 mg sublingually. Arterial blood gases and blood pressure and pulse were measured at 5-min intervals for 30 min after nitroglycerin. There was a slight decrease in arterial O2 tension for the duration of the study; the maximal change was from a mean pre-nitroglycerin value of 53.5 mm Hg to 50.3 mm Hg at 20 min. In addition, there was a slight reduction in arterial CO2 tension and bicarbonate for 25 min. It is postulated that decreased O2 transport (due to increased hypoxemia and probably decreased cardiac output) plus hypocapnia were a sufficient stimulus to raise blood lactate. It is recommended that in patients receiving nitroglycerin who have obstructive airway disease, attention be directed toward the effect on arterial blood gases.