Improved Cardiac Performance by Salbutamol, a Selective β2-Agonist, in Chronic Cor Pulmonale

Abstract

The effects of salbutamol, a relative specific beta 2-agonist, on hemodynamics and arterial blood oxygenation, were studied in 12 patients with chronic cor pulmonale. The studies were done during heart catheterization at rest (n = 12) and during arm bicycle exercise (n = 7) before and during salbutamol infusion of 0.2 microgram/kg/min. At rest, salbutamol significantly increased cardiac index on average by 31%, stroke volume index by 11%, and heart rate by 12 beats/min. Mean pulmonary artery pressure was not changed by salbutamol, whereas a small reduction in mean arterial pressure was observed. The vascular resistance was reduced by 15% in pulmonary and 24% in systemic circulation. Similar hemodynamic changes by salbutamol were observed during exercise. Arterial oxygen tension and saturation were not changed by salbutamol, but a significant rise in mixed venous oxygen saturation and oxygen delivery were observed both at rest and during exercise. Thus, salbutamol infusion improves the cardiac performance in patients with chronic cor pulmonale through a chronotropic effect combined with vasodilation in both the systemic and pulmonary circulation and thereby increased stroke volume. No deleterious effects on arterial blood oxygenation by salbutamol infusion were observed.