The impact of oxygen saturation on functional performance in patients with COPD on long-term oxygen therapy – a randomized crossover trial

<bold>Background:</bold> Minimizing hypoxemia during submaximal test has a positive effect on exercise capacity and dyspnea in patients with COPD on long-term oxygen therapy (LTOT). However, the impact of optimizing oxygenation during everyday tasks remains unexplored. Therefore, we investigated the effects of maintaining a target saturation on Activities of Daily Living (ADL) using an automated oxygen system compared to conventional fixed oxygen flow. <bold>Methods:</bold> In a double-blinded, randomized crossover trial, 31 patients with COPD on LTOT performed two Glittre-ADL tests to assess the functional performance of everyday activities using a) an adjusted flow from 0-8 L/min targeting a SpO2 of 90-94% and b) their fixed oxygen dose. An electronic device (O2matic HOT) automatically titrated the oxygen based on information from a Bluetooth wrist pulse oximeter. <bold>Results:</bold> The patients reduced the time to perform the ADL-test by median (IQR) 38 (12-73) seconds, p<0.001, using automated titration compared to the fixed oxygen flow. The oxygen flow in the automated arm more than tripled to 5.4 (4.1 – 6.8) L/min vs. 1.6 (1.1-2.1) L/min (fixed) during the test, p<0.001, while the time spend within SpO2-target was increased from 24% to 47%, p<0.001. Correspondingly, the patients experienced less dyspnea (BorgCR10); 5 (3-7) vs. 6 (4-8), p<0.001. Twenty-seven (87%) patients exceeded the minimal clinical important difference (MCID) in either the change of dyspnea score or time difference to complete the ADL-test. <bold>Conclusions:</bold> Extending the time spent within target saturation reduced dyspnea and improved functional performance in activities of daily living in patients with COPD on LTOT.