Evaluation of the Performance of a Demand Oxygen Delivery System With a Built-In Reservoir

Background: Patients with interstitial lung disease (ILD) and hypoxemia often require long-term home-based oxygen therapy. A demand oxygen delivery system (DODS), which is particularly useful during outdoor activities, requires careful evaluation regarding its effectiveness for alleviating hypoxemia, particularly during exertion. OxyCube, a DODS with a built-in second tank, was designed to deliver precisely adjusted oxygen pressure during inspiration. This study aimed to quantitatively compare the efficacy of OxyCube with a nontank DODS in ILD subjects who experienced exertional hypoxemia. Methods: In this randomized crossover trial, 9 ILD subjects with hypoxemia (SpO2 < 90%) during a 6-min walk test (6MWT) performed ergometer exercise loads under a fixed flow setting 3 times. The initial test was used to determine the maximal oxygen uptake (V˙O2max) of each subject. A subsequent comparative test used 80% of the maximum load, alternating between the OxyCube and a sham device. The primary end point was the change in SpO2 from the baseline (ΔSpO2). Results: OxyCube consistently showed a significantly lower reduction in SpO2 than the sham device during exercise, with the most considerable difference being at the 6MWT (6.3 ± 3.0% vs 9.7 ± 3.0%, P < .01). No significant differences in ΔHR and ΔBorg score between the devices underscored the quantitative approach of the study. Conclusions: OxyCube improved exertional hypoxemia in subjects with ILD compared with the sham device. These findings suggest that OxyCube may offer benefits for patients with ILD showing hypoxemia during exertion, although a larger study is required to validate the efficacy.