Journal of applied physiology
-
Patients with idiopathic pulmonary fibrosis (IPF) usually develop hypoxemia and pulmonary hypertension when exercising. To what extent endothelium-derived vasodilating agents modify these changes is unknown. The study was aimed to investigate in patients with IPF whether exercise induces changes in plasma levels of endothelium-derived signaling mediators, and to assess the acute effects of inhaled nitric oxide (NO) on pulmonary hemodynamics and gas exchange, at rest and during exercise. ⋯ Inhaled NO reduced mean pulmonary arterial pressure at rest (-4.6 ± 2.1 mmHg) and during exercise (-11.7 ± 7.1 mmHg) (P = 0.001 and P = 0.004, respectively), without altering arterial oxygenation or ventilation-perfusion distributions in any of the study conditions. Alveolar-to-capillary oxygen diffusion limitation, which accounted for the decrease of arterial Po(2) during exercise, was not modified by NO administration. We conclude that, in IPF, some endothelium-derived signaling molecules may modulate the development of pulmonary hypertension during exercise, and that the administration of inhaled NO reduces pulmonary vascular resistance without disturbing gas exchange.