Comparing the efficacy of exertional oxygen delivery by continuous versus demand-based flow systems during 6-minute walk test in patients with fibrotic interstitial lung disease and COPD in a hospital setting (OXYCODE): a protocol for a randomised trial.

introductionFibrotic interstitial lung diseases (F-ILD) are severe and often progressive lung disorders that frequently lead to respiratory failure, with patients experiencing high symptom burdens, including severe dyspnoea. This is also evident in patients with severe chronic obstructive pulmonary disease (COPD). Many patients will eventually require ambulatory oxygen therapy (AOT) due to exertional desaturation. Although AOT has shown benefits like increased walking distance and improved quality of life, adherence remains a challenge due to practical issues. AOT can be given by oxygen bottles that provide continuous oxygen flow or as portable concentrators; however, there is a lack of studies comparing the different methods and assessing patient preferences. Data from the present study help guide the selection of patients for different AOTs and provide information on patient preferences. METHODS AND ANALYSIS: The study design is a single-centre, randomised, open-label cross-over exploratory comparative study to investigate the efficacy of two different oxygen delivery systems. Patients with COPD or F-ILD who, during a 6-minute walk test (6MWT), can walk at least 50 m and desaturate below 88% are eligible for inclusion in the study. The participants are randomised to perform the 6MWT with either oxygen bottles or portable concentrators first. The primary endpoint is the difference in the lowest oxygen saturation (SpO2) between the two systems. Secondary endpoints include, among others, the difference in percentage of time and number of minutes when SpO2 falls below 88%, mean and maximum pulse rate, and distance and time taken to recover during the 6MWT. Quality of life and patient preferences will be evaluated by scores from the COPD assessment test and the King's Brief Interstitial Lung Disease health status questionnaire to help gain a better understanding of symptom impact during activity and limitations in daily life. ETHICS AND DISSEMINATION: The study has been approved by the Central Denmark Region Committees on Health Research Ethics (1-10-72-115-24). The results of this trial will be submitted for publication in an international peer-reviewed journal. TRIAL REGISTRATION NUMBER: NCT06767904.