Effect of High-Flow Oxygen on Exercise Performance in COPD Patients. Randomized Trial

Abstract

Background: High-flow oxygen therapy (HFOT) provides oxygen-enriched, humidified, and heated air at high flow rates via nasal cannula. It could be an alternative to low-flow oxygen therapy (LFOT) which is commonly used by patients with chronic obstructive pulmonary disease (COPD) during exercise training.Research Question: We evaluated the hypothesis that HFOT improves exercise endurance in COPD patients compared to LFOT.Methods: Patients with stable COPD, FEV1 40–80% predicted, resting pulse oximetry (SpO2) ≥92%, performed two constant-load cycling exercise tests to exhaustion at 75% of maximal work rate on two different days, using LFOT (3 L/min) and HFOT (60 L/min, FiO2 0.45) in randomized order according to a crossover design. Primary outcome was exercise endurance time, further outcomes were SpO2, breath rate and dyspnea.Results: In 79 randomized patients, mean ± SD age 58 ± 9 y, FEV1 63 ± 9% predicted, GOLD grades 2-3, resting PaO2 9.4 ± 1.0 kPa, intention-to-treat analysis revealed an endurance time of 688 ± 463 s with LFOT and 773 ± 471 s with HFOT, mean difference 85 s (95% CI: 7 to 164, P = 0.034), relative increase of 13% (95% CI: 1 to 28). At isotime, patients had lower respiratory rate and higher SpO2 with HFOT. At end-exercise, SpO2 was higher by 2% (95% CI: 2 to 2), and Borg CR10 dyspnea scores were lower by 0.8 points (95% CI: 0.3 to 1.2) compared to LFOT.Interpretation: In mildly hypoxemic patients with COPD, HFOT improved endurance time in association with higher arterial oxygen saturation, reduced respiratory rate and less dyspnea compared to LFOT. Therefore, HFOT is promising for enhancing exercise performance in COPD.Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT03955770.

The Impact of Exercise Training and Supplemental Oxygen on Peripheral Muscles in Chronic Obstructive Pulmonary Disease: A Randomized Controlled Trial

“…Data also suggest an important role of supplemental oxygen during exercise training, which significantly increased the functional training effects on peak exercise intensities (30). Although oxygen supplementation during training may have limited direct effects on muscle oxygenation in certain conditions/patients, it also inhibits carotid body stimulation and reduces thereby respiratory drive (30,35,36). Moreover, it is known that supplemental oxygen can improve pulmonary hemodynamics by local vasodilatation, leading to lower pulmonary resistances and thus increased cardiac output, allowing thereby better exercise tolerance during training sessions (37).…”

“…Different study designs and technical aspects of oxygen delivery might have contributed to the inconclusive discussion (16). High oxygen flows, gas-specific exercise prescription, higher exercise intensities, and progressive training adaptations were proposed as critical issues (15,30,33,36). However, the impact of supplemental oxygen seems more evident on maximal workloads than on submaximal exercise capacity (25,30,32).…”

Automated O2Titration Alone or With High-Flow Nasal Cannula During Walking Exercise in Chronic Lung Diseases

“…High-flow nasal cannula is another technique that is being considered to enhance exercise tolerance in subjects with chronic respiratory diseases. [22][23][24][25] Proposed mechanisms of action that are complementary to those of supplemental oxygen include (1) reduced breathing frequency, (2) reduced dead-space ventilation, and (3) generation of a small PEEP-like effect counterbalancing intrinsic PEEP and reducing work of breathing. 26,27 Interestingly, automated O 2 titration can be coupled with high-flow nasal cannula to potentiate their respective efficacy to alleviate exertional dyspnea and improve exercise tolerance.…”