Inhaled Selective Pulmonary Vasodilators

Perioperative PHTN and RV dysfunction are important, because they are common and significantly worsen patient outcome. Their perioperative management is tiered, integrated, and multimodal. The first tier includes optimizing ventilation to achieve hyperoxia, hypocarbia, and alkalosis, because this metabolic milieu promotes pulmonary vasodilation. The second tier of management focuses on inotropic support of the right ventricle, typically by combining epinephrine and milrinone. The third tier of management is the niche of selective pulmonary vasodilation, with or without intravenous adjuncts. At present, the 2 main selective pulmonary vasodilators are inhaled NO and inhaled prostaglandin I2-Inhaled prostaglandin I2 is currently preferred over NO as a result of clinical equivalency, greater affordability, better toxicity profile, and easier mode of administration. Newer adjuncts include natriuretic peptide, endothelin antagonists, and vasopressin. Natriuretic peptide is a moderately selective pulmonary vasodilator that enhances biventricular and renal function. Vasopressin is a mild pulmonary vasodilator and a selective systemic vasoconstrictor: its indication is in pulmonary hypertension with vasodilatory shock. Synergistic combinations of inhaled pulmonary vasodilators will be increasingly applied in the management of perioperative PHTN and RV dysfunction, as progress continues to improve perioperative outcome in these conditions.