[Inhaled vasodilators]

First reports on the use of inhaled nitric oxide (NO) in patients were published in 1991. These reports confirmed data from animal experiments which suggested a selective vasodilatory effect of inhaled NO in pulmonary vessels. As the main clinical effects, both improved oxygenation and a drop of pulmonary artery pressure despite unchanged arterial pressure were observed. Since then, many studies have evaluated the effects of inhaled NO as well as of other aerosolised vasodilators (e.g. PGI(2), PGE(1), nitrates, phosphodiesterase-inhibitors) in patients with pulmonary hypertension, acute right heart failure and/or life-threatening hypoxemia. However, primary pulmonary hypertension of the newborn (PPHN) is the only indication for which inhaled NO has been clinically approved so far. Although an obvious clinical benefit in outcome from inhaled vasodilators has never been formally documented, good clinical efficacy has resulted in an increasing "off label" use of the concept both in Germany and worldwide, particularly with respect to anaesthesia and intensive care medicine. The present article aims to review both the pathophysiological and pharmacological basis of inhaled vasodilators, to critically reevaluate their potential clinical indications and to give a perspective on future developments in the field.