A randomized cross-over trial on the direct effects of oxygen supplementation therapy using different devices on cycle endurance in hypoxemic patients with Interstitial Lung Disease

BACKGROUND: In patients with interstitial lung disease (ILD) a cardinal feature is exercise intolerance, often associated with significant dyspnea and severe hypoxemia. Supplemental oxygen therapy may be offered during exercise. The Oxymizer is a nasal cannula with an incorporated reservoir with the potential to deliver higher oxygen doses to the patient. OBJECTIVE: The primary aim was to investigate the effect of supplemental oxygen delivered via Oxymizer compared to a conventional nasal cannula (CNC) in patients with ILD during constant work rate tests (CWRT). Secondary aim was to evaluate effects on oxygen saturation (SpO(2)), dyspnea and heart rate at isotime. METHODS: In this randomized crossover study 24 ILD patients established on long-term oxygen treatment were included. Patients performed four cycling CWRT at 70% of their peak work rate; twice with the Oxymizer and twice with the CNC. RESULTS: Twenty-one patients finished all CWRTs (age 60 ± 10.9 years, VC 55.4 ± 23.0%predicted). Cycle endurance time was significantly higher while using the Oxymizer compared to CNC (718 ± 485 vs. 680 ± 579 seconds, p = 0.02), and SpO(2) at isotime was significantly higher while using the Oxymizer (85.5 ± 6.7 vs. 82.8± 7.2, p = 0.01). Fifteen of the 21 (71%) patients cycled longer with the Oxymizer. There were no significant differences for dyspnea and heart rate. CONCLUSIONS: Supplemental oxygen provided by the Oxymizer significantly, but modestly, improved cycle endurance time and SpO(2) at isotime in ILD patients compared to CNC.