Determinants of Improved Dyspnea and Exercise Tolerance With Nasal High-Flow O2 Therapy in Fibrotic Interstitial Lung Disease: A Pilot Physiological Study.

We tested the respective effect of high-flow and supplemental O2 from nasal high-flow O2 therapy (NHFO2) on dyspnea and exercise tolerance in fibrotic interstitial lung disease. Supplemental O2 and NHFO2 (but not high-flow) provided improvements in these outcomes at "iso-O2 saturation" due to reduced ventilatory requirements. Physiological benefits derived from O2 supplementation are thus likely primary drivers of dyspnea relief and improved exercise tolerance on NHFO2 (vs air) in these patients.