Modulation of pulmonary blood flow in patients with acute respiratory failure

•Hypoxemia due to impairment of pulmonary ventilation and perfusion matching is one of the most common causes of respiratory failure requiring intensive care unit admission.•Inhaled nitric oxide is a selective pulmonary vasodilator that releases pulmonary vasoconstriction and increases perfusion in ventilated regions, whose effect is commonly estimated by improvement in blood oxygenation.•The administration of inhaled nitric oxide led to a redistribution of blood perfusion in the lungs in all patients, recorded at the bedside and visualized in vivo using electrical impedance tomography, regardless of the response in blood oxygenation.•The possibility of monitoring and modulating blood distribution lay the foundations for testing new therapies aimed at optimizing regional perfusion in the lungs.