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

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.

In this randomized crossover trial, 9 ILD subjects with hypoxemia (S_pO2 < 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 S_pO2 from the baseline (ΔS_pO2).

OxyCube consistently showed a significantly lower reduction in S_pO2 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.

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.