In patients with severe interstitial lung disease (ILD), the use of nasal high-flow (NHF) oxygen increases endurance time and delays sensations of leg fatigue and dyspnea during exercise, according to a study in Respiratory Medicine.
The study included 25 patients (mean age, 72.8±6.7 years) with severe ILD, including 18 with idiopathic pulmonary fibrosis and 7 with “other” disease (such as lymphangioleiomyomatosis and dermatomyositis). Over 2 consecutive days, patients underwent a cardiopulmonary exercise testing session in the setting of room air to identify the maximal cycling exercise response.
The second testing session comprised 3 endurance cycling tests reaching 70% of the maximal workload recorded during the first test. The order of events in the second test included a cycling test while breathing room air, a cycling test while breathing supplemental oxygen (4 L min−1 O2), and a third test using NHF oxygen (inspiratory O2 fraction 0.5, 30-50 L min−1, and heated to 34◦ C and humidified).
Tests that used NHF oxygen were associated with significantly longer endurance time compared with testing that used supplemental oxygen and room air (mean, 618±297 seconds vs 369±217 seconds vs 171±76 seconds; P <.001). Compared with room air, endurance time improved by 216±285% with oxygen supplementation and 361±391% with NHF oxygen.
At rest, pulse and muscle oxygen saturation levels were higher under oxygen supplementation and NHF oxygen compared with room air (P <.05). Leg fatigue and dyspnea were comparable between the 3 tests at rest but increased during exercise.
The levels of leg fatigue and dyspnea were less severe with oxygen supplementation and NHF oxygen compared with room air, but similar levels of leg fatigue and dyspnea were reported at the completion of the testing. Approximately 64% of patients who ended their NHF oxygen test reported greater leg fatigue or less dyspnea compared with what was reported at the end of the oxygen supplementation test. The remaining 36% of patients ended their NHF oxygen tests with similar leg fatigue and dyspnea as reported at the end of the tests with oxygen supplementation.
Limitations of this study included its small sample size as well as the nonblinded design, which the researchers suggest may have created a placebo effect.
Given these limitations, the researchers wrote that additional “studies are needed to clarify the effect of NHF [oxygen] on exercise responses but also to determine whether NHF [oxygen] may be a useful tool for facilitating exercise training in this population of respiratory patients.”
Al Chikhanie Y, Veale D, Verges S, Hérengt F. The effect of heated humidified nasal high flow oxygen supply on exercise tolerance in patients with interstitial lung disease: a pilot study. Respir Med. Published online June 29, 2021. doi:10.1016/j.rmed.2021.106523