Supplemental oxygen improves exercise capacity in IPF patients with exertional desaturation

Abstract

The efficacy of supplemental oxygen during exercise remains unclear for patients with IPF, as there have been conflicting results from recent prospective studies with small sample sizes. This prospective, single-blind, randomized, crossover trial evaluated the efficacy of supplemental oxygen compared with placebo air during exercise in consecutive patients with IPF without resting hypoxaemia at initial evaluation. Patients with <90% SpO2 in a 6MWT using room air were randomly assigned to a CWRET at 80% of peak work rate with oxygen or placebo air gas via nasal cannula at 4 L/min. The primary endpoint was the effect of supplemental oxygen on endurance time. We recruited 72 consecutive patients (median age: 66.5 years, % FVC: 84.6%, % DLCO : 61.4%). Supplemental oxygen significantly increased the endurance time (340-424 s; P < 0.001) and minimum SpO2 (88.0-94.0%; P < 0.001) compared with placebo air. Furthermore, supplemental oxygen significantly improved dyspnoea and leg fatigue. In a multivariate linear regression analysis, the endurance time on air was an independent explanatory variable of the improvement rate of endurance time (P = 0.02). In mild-moderate IPF with exercise-induced hypoxaemia even without resting hypoxaemia, supplemental oxygen during exercise improved the endurance time, desaturation and subjective symptoms. Patients with shorter endurance times with placebo air showed better improvement with supplemental oxygen.