Effect of Nocturnal Oxygen Therapy on Nocturnal Hypoxemia and Sleep Apnea Among Patients With Chronic Obstructive Pulmonary Disease Traveling to 2048 Meters
Authors: Lu Tan, Tsogyal D. Latshang, Sayaka S. Aeschbacher, Fabienne Huber, Deborah Flueck, Mona Lichtblau, Stefanie Ulrich, Elisabeth D. Hasler, Philipp M. Scheiwiller, Silvia Ulrich, Konrad E. Bloch, Michael Furian
Journal: JAMA Network Open (2020)

<h3>Importance</h3> There are no established measures to prevent nocturnal breathing disturbances and other altitude-related adverse health effects (ARAHEs) among lowlanders with chronic obstructive pulmonary disease (COPD) traveling to high altitude. <h3>Objective</h3> To evaluate whether nocturnal oxygen therapy (NOT) prevents nocturnal hypoxemia and breathing disturbances during the first night of a stay at 2048 m and reduces the incidence of ARAHEs. <h3>Design, Setting, and Participants</h3> This randomized, placebo-controlled crossover trial was performed from January to October 2014 with 32 patients with COPD living below 800 m with forced expiratory volume in the first second of expiration (FEV<sub>1</sub>) between 30% and 80% predicted, pulse oximetry of at least 92%, not requiring oxygen therapy, and without history of sleep apnea. Evaluations were performed at the University Hospital Zurich (490 m, baseline) and during 2 stays of 2 days and nights each in a Swiss Alpine hotel at 2048 m while NOT or placebo treatment was administered in a randomized order. Between altitude sojourns, patients spent at least 2 weeks below 800 m. Data analysis was performed from January 1, 2015, to December 31, 2018. <h3>Intervention</h3> During nights at 2048 m, NOT or placebo (room air) was administered at 3 L/min by nasal cannula. <h3>Main Outcomes and Measures</h3> Coprimary outcomes were differences between NOT and placebo intervention in altitude-induced change in mean nocturnal oxygen saturation (SpO<sub>2</sub>) as measured by pulse oximetry and apnea-hypopnea index (AHI) measured by polysomnography during night 1 at 2048 m and analyzed according to the intention-to-treat principle. Further outcomes were the incidence of predefined ARAHE, other variables from polysomnography results and respiratory sleep studies in the 2 nights at 2048 m, clinical findings, and symptoms. <h3>Results</h3> Of the 32 patients included, 17 (53%) were women, with a mean (SD) age of 65.6 (5.6) years and a mean (SD) FEV<sub>1</sub>of 53.1% (13.2%) predicted. At 490 m, mean (SD) SpO<sub>2</sub>was 92% (2%) and mean (SD) AHI was 21.6/h (22.2/h). At 2048 m with placebo, mean (SD) SpO<sub>2</sub>was 86% (3%) and mean (SD) AHI was 34.9/h (20.7/h) (<i>P</i> &lt; .001 for both comparisons). Compared with placebo, NOT increased SpO<sub>2</sub>by a mean of 9 percentage points (95% CI, 8-11 percentage points;<i>P</i> &lt; .001), decreased AHI by 19.7/h (95% CI, 11.4/h-27.9/h;<i>P</i> &lt; .001), and improved subjective sleep quality measured on a visual analog scale by 9 percentage points (95% CI, 0-17 percentage points;<i>P</i> = .04). During visits to 2048 m or within 24 hours after descent, 8 patients (26%) using placebo and 1 (4%) using NOT experienced ARAHEs (<i>P</i> &lt; .001). <h3>Conclusions and Relevance</h3> Lowlanders with COPD experienced hypoxemia, sleep apnea, and impaired well-being when staying at 2048 m. Because NOT significantly mitigated these undesirable effects, patients with moderate to severe COPD may benefit from preventive NOT during high altitude travel. <h3>Trial Registration</h3> ClinicalTrials.gov Identifier:NCT02150590