“…Inhaled epoprostenol (iEpo) is a synthetic prostacyclin analog that is used off-label as a selective pulmonary vasodilator (SPV) in critically ill patients with refractory hypoxemia, right ventricular failure, and postcardiac surgery pulmonary hypertension (PH) ( 1 , 2 ). By relaxing pulmonary vascular smooth muscle in ventilated portions of the lung, iEpo improves ventilation-perfusion (V/Q) matching and reduces pulmonary vascular resistance (PVR) ( 3 , 4 ). Published studies suggest that SPV therapy decreases pulmonary artery pressures, augments cardiac output, and improves oxygenation ( 2 , 5 ).…”