TY - JOUR T1 - Oxygen supplementation during exercise improves leg muscle fatigue in chronic fibrotic interstitial lung disease JF - Thorax JO - Thorax SP - 672 LP - 680 DO - 10.1136/thoraxjnl-2020-215135 VL - 76 IS - 7 AU - Mathieu Marillier AU - Anne-Catherine Bernard AU - Samuel Verges AU - Onofre Moran-Mendoza AU - Denis E O'Donnell AU - José Alberto Neder Y1 - 2021/07/01 UR - http://thorax.bmj.com/content/76/7/672.abstract N2 - Background Exercise-induced hypoxaemia is a hallmark of chronic fibrotic interstitial lung disease (f-ILD). It remains unclear whether patients’ severe hypoxaemia may exaggerate locomotor muscle fatigue and, if so, to what extent oxygen (O2) supplementation can ameliorate these abnormalities.Methods Fifteen patients (12 males, 9 with idiopathic pulmonary fibrosis) performed a constant-load (60% peak work rate) cycle test to symptom limitation (Tlim) while breathing medical air. Fifteen age-matched and sex-matched controls cycled up to patients’ Tlim. Patients repeated the exercise test on supplemental O2 (42%±7%) for the same duration. Near-infrared spectroscopy assessed vastus lateralis oxyhaemoglobin concentration ((HbO2)). Pre-exercise to postexercise variation in twitch force (∆Tw) induced by femoral nerve magnetic stimulation quantified muscle fatigue.Results Patients showed severe hypoxaemia (lowest O2 saturation by pulse oximetry=80.0%±7.6%) which was associated with a blunted increase in muscle (HbO2) during exercise vs controls (+1.3±0.3 µmol vs +4.4±0.4 µmol, respectively; p<0.001). Despite exercising at work rates ∼ one-third lower than controls (42±13 W vs 66±13 W), ∆Tw was greater in patients (∆Tw/external work performed by the leg muscles=−0.59±0.21 %/kJ vs −0.25±0.19 %/kJ; p<0.001). Reversal of exertional hypoxaemia with supplemental O2 was associated with a significant increase in muscle (HbO2), leading to a reduced decrease in ∆Tw in patients (−0.33±0.19 %/kJ; p<0.001 vs air). Supplemental O2 significantly improved leg discomfort (p=0.005).Conclusion O2 supplementation during exercise improves leg muscle oxygenation and fatigue in f-ILD. Lessening peripheral muscle fatigue to enhance exercise tolerance is a neglected therapeutic target that deserves clinical attention in this patient population.Data are available on reasonable request. Data available from the authors on request—unidentified patients in excel/SPSS files. ER -