In this study, our expert panel achieved consensus on 20 items that can be used to guide supplemental oxygen use in patients with fibrotic ILD. We further identified several areas where respondents were unsure or where consensus could not be met, suggesting future areas where research efforts should be focused. Finally, we identified discrepancies between scenarios where clinicians would recommend oxygen and poor patient access, based on regional funding criteria or testing requirements.
These findings may be used to develop clinical practice recommendations and funding policies for supplemental oxygen for this patient population, pending more robust evidence. A proposed approach to the assessment and prescription of supplemental oxygen for patients with fibrotic ILD is presented in figure 4.
Proposed algorithm for assessment and prescription of oxygen. Decisions regarding supplemental oxygen use should be made with consideration of the benefits and risks, as well as patient values and preferences. ILD: interstitial lung disease; PaO2: arterial oxygen tension; SpO2: peripheral oxygen saturation; 6MWT: 6-min walk test.
Overall, experts agreed that supplemental oxygen is a safe therapeutic intervention that should be considered in conjunction with patient wishes and goals, and that newer portable systems should be developed to facilitate its use. There was consensus to recommend oxygen in cases of severe resting or exertional hypoxaemia and that nocturnal desaturation is an important clinical parameter. Experts agreed that the goals of oxygen use are multifaceted, primarily aiming to improve the patient experience, targeting symptoms and/or exercise tolerance. Experts recommend oxygen use in cases of symptomatic exertional desaturation, highlighting the different approach to oxygen prescription for patients with fibrotic ILD compared with patients with COPD. A large randomised trial found that supplemental oxygen did not improve survival, functional status or quality of life in stable COPD patients with moderate resting hypoxaemia or isolated exertional desaturation [25]. However, these findings should be extrapolated with caution to patients with fibrotic ILD, given the differing physiology and severity of exertional desaturation between these groups [4, 26].
The only clinical scenario for which there was 100% strong agreement to recommend oxygen was in cases of severe resting hypoxaemia, consistent with published guidelines for ILD management [16, 17, 27]. Some country-specific recommendations suggest ambulatory oxygen for patients with ILD or IPF if breathlessness or exercise limitations exist in the context of exertional desaturation [17, 27]. In our study, most experts recommended oxygen below an exertional desaturation threshold between 85% and 89%, and particularly when patients have symptoms or exercise intolerance that improved with oxygen therapy. Given the dynamic and effort-dependent nature of exertional desaturation, expert commentary suggested that a single measured SpO2 in isolation provides inadequate data to guide oxygen prescription. Desaturation level should likely be considered in conjunction with symptoms, exercise tolerance and possibly with evidence of improvement in these parameters with oxygen therapy.
All clinical decisions, including the use of supplemental oxygen, should be made in partnership with patients and, where appropriate, caregivers. Prior qualitative and mixed-methods studies have addressed the goals of oxygen use from both the healthcare provider and patient perspective [28–30]. The summarised goals appear consistent, primarily focused on improving symptoms and exercise tolerance. The current study focused uniquely on healthcare providers' opinions regarding the indications and goals of oxygen for patients with fibrotic ILD. We wanted to understand the recommendations being made by clinicians, as this is inexorably related to how information is presented to patients. The discussion of anticipated benefits and potential risks or complications of therapy can influence a patient's decision to accept or decline treatment in shared decision-making models [31]. In the absence of definitive evidence, we hope that our findings can provide a framework for such discussions. Further studies addressing internationally diverse patient and caregiver perspectives would add important data guiding the role of oxygen. Despite differences in clinical practice patterns among our experts, there was a consensus that clinicians should consider the balance of benefits versus burdens of supplemental oxygen for individual patients with fibrotic ILD, an essential point underlying all work on this topic.
The Delphi technique is a validated methodology used in healthcare research to develop consensus-based recommendations when robust evidence is lacking. Through iterative questionnaires, a group of experts provides their opinion after considering the collective responses of prior rounds, while maintaining anonymity [23, 24]. We believe that the Delphi technique was a justified research tool to identify current best practices in supplemental oxygen use among patients with fibrotic ILD. Based on expert input representing 17 countries, access to oxygen funding appears heterogeneous by practice location. In some regions, there are few barriers to oxygen funding, while in others oxygen is only accessible if patients pay for the equipment themselves or if they qualify via predefined testing algorithms. One-quarter of experts reported that no oxygen funding is available for patients with exertional desaturation <80% in the absence of attributable symptoms, highlighting the heterogeneity of access to this therapy in different practice areas. Standardising the clinical indications for oxygen may make access more equitable across regions, but this is a complex goal given the variability in healthcare systems and oxygen reimbursement policies worldwide. Furthermore, technological advances should be prioritised to reduce the burden of portable oxygen devices for advanced lung disease patients [32, 33].
This study has limitations. First, our participant selection strategy was not based on predefined or publication-based criteria. Rather, we sought to achieve representative diversity of experience and opinion from a large pool of potential international ILD experts. We believe this is particularly important with our study question, given the lack of high-quality evidence. In support of our expert selection approach are the very high participation and survey completion rates. Participants from the Asian and African continents are under-represented in this survey, and future work should aim to better understand clinical practice patterns in these regions. Based on the survey design of this study, we were unable to further qualify the expert responses to define specific clinical scenarios in which supplemental oxygen would be used. Given the unique circumstances of each patient encounter, this was not feasible. Finally, the consensus among experts does not necessarily equate to scientific truth or clinical validity and lack of consensus highlights differences in perspectives regarding complex issues. A Delphi survey is not a substitute for rigorous prospective studies and many of the questions posed herein, including those meeting consensus, should be further addressed in randomised trials of oxygen therapy, where possible.
Conclusions
An international group of ILD experts achieved consensus on 20 items to guide supplemental oxygen use in patients with fibrotic ILD. Desaturation severity, hypoxaemia-attributable symptoms, exercise tolerance and patient preference should be considered when recommending oxygen. While there is a lack of evidence to guide clinical recommendations, oxygen is an important component of patient management and well-designed prospective studies are urgently needed to answer outstanding questions. The current data may provide a framework to guide clinical decision making and funding policy for oxygen therapy in this patient population, pending the availability of high-quality evidence.
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