LAUSR

Since 1965, when Dr. Petty first filled the prototype of a portable oxygen tank with liquid oxygen and pilot tested supplemental oxygen therapy (O2) on six patients with hypoxia, O2 has become a mainstay of therapy for many patients with chronic lung disease. Absent robust, disease-specific data, scientific rationale, clinical experience, extrapolation of data from the Chronic Obstructive Pulmonary Disease (COPD) literature (1, 2), and results from a handful of single-center studies (3, 4) have suggested a beneficial role for O2 in patients with interstitial lung disease (ILD). Those of us who prescribe O2 to patients with ILD have heard firsthand how it helps. However, O2 presents certain challenges to patients with ILD and their caregivers: patients feel physically and emotionally constrained by O2, “tied to the hoses” that deliver it to their lungs (5), and for both patients with ILD and their caregivers, O2 is a major contributor to their lives “getting smaller” (6), what our lab calls the “Shrinking World Syndrome.” The household-altering challenges O2 presents remind us that it should be prescribed to patients with ILD who need it only after a detailed discussion that includes an educational overview of O2, recommendations for how to use it (correctly), and disclosure of what hardships and benefits the patient (and their caregiver) might expect from O2. Before that discussion, as O2 prescribers, we need to assess and manage our own expectations for how patients will use O2. Ideally, we would like patients’ SpO2 higher than 89% at all times, but expecting this to happen is unrealistic. Even within the tight confines of a therapeutic trial, this lofty goal cannot be met: In the recently completed LOTT trial in chronic obstructive pulmonary disease, subjects prescribed O2 for use 24 hours/day used it, on average, “only” 15.6 hours/day (7). We must accept that each patient will discern for themselves how our expectations for O2 use fit into their realities. In the real world, patients with ILD adopt a “some is better than none” approach to O2: When out and about, they will reduce O2 flow to ensure they have some left to get them back home, even if this means SpO2 will be lower than 90% or episodically plummet. Another (in today’s healthcare climate) possibly unreasonable expectation is that an O2 prescription should include a costcovered finger pulse oximeter. For patients with ILD, I believe correct use of O2 means patients are given the liberty to adjust their O2 flow as needed to maintain SpO2 higher than 89%. Continually staring at their pulse oximeter is no way for patients to live, so once the flows they need have been established, as long as things are stable, having them “check in” with their oximeter occasionally while performing activities of differing energy demands is probably adequate. Recognizing there are no data to support it, this approach will hopefully give them some sense of control over their disease while also improving other outcomes. In our discussions with patients with ILD and their caregivers, we also need to manage patients’ expectations around O2. But what do patients with ILD expect? In this month’s issue of the AnnalsATS, Khor and colleagues (pp. 888–895) interviewed 24 patients with ILD to help answer this question (8). They contrasted data from 12 patients who had been using O2 for between 3 and 51 months with data from 12 patients who needed O2 but declined it after a discussion with their treating physician. The nonusers perceived O2 as a symbol of end-stage disease and believed they did not need it at the time of the interview. When “needed,” they expected O2 would “probably make me feel more comfortable breathing,” that is, improve dyspnea. Interestingly, users recognized several benefits of O2, but for the most part, dyspnea was not specifically mentioned. They perceived improved mobility (“I can walk around the house easily, even walk outside”) and better exercise tolerance, presumably as a result of less dyspnea, but not stated as such. They also realized O2 made them “feel...stronger,” stopped their hearts from “pounding” uncomfortably, alleviated exhaustion, and reduced cough. However, O2 also had shortcomings: some users expected “resolution or marked reduction in their symptoms,” but that did not occur; some were anxious about running out of O2; and others found that O2 “affects their freedom,” and they became less physically active while using O2. Knowing a few intricate details would have helped further improve understanding