Effect of Nocturnal Oxygen Therapy on Nocturnal Hypoxemia and Sleep Apnea Among Patients With Chronic Obstructive Pulmonary Disease Traveling to 2048 Meters : A Randomized Clinical Trial

Key Points

Question

Can nocturnal oxygen therapy prevent hypoxemia and sleep apnea among lowlanders with chronic obstructive pulmonary disease when traveling to high altitude?

Findings

In this randomized crossover trial of 32 lowlanders with chronic obstructive pulmonary disease, nocturnal oxygen therapy improved their mean nocturnal oxygen saturation and apnea-hypopnea index during a night at 2048 m. Nocturnal oxygen therapy also reduced the incidence of altitude-induced adverse health effects requiring medical treatment or descent to lower altitude by 85% compared with placebo.

Meaning

Patients with chronic obstructive pulmonary disease may benefit from nocturnal oxygen therapy during travel to high altitude because it reduces nocturnal hypoxemia, sleep disordered breathing, and other adverse health effects.

Abstract

This randomized clinical trial evaluates whether nocturnal oxygen therapy (NOT) prevents nocturnal hypoxemia and breathing disturbances among lowlanders with chronic obstructive pulmonary disease (COPD) in the first night of a stay at 2048 m and reduces the incidence of altitude-related adverse health effects.

Abstract

Importance

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.

Objective

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.

Design, Setting, and Participants

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 ₁) 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.

Intervention

During nights at 2048 m, NOT or placebo (room air) was administered at 3 L/min by nasal cannula.

Main Outcomes and Measures

Coprimary outcomes were differences between NOT and placebo intervention in altitude-induced change in mean nocturnal oxygen saturation (SpO ₂) 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.

Results

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 ₁ of 53.1% (13.2%) predicted. At 490 m, mean (SD) SpO ₂ was 92% (2%) and mean (SD) AHI was 21.6/h (22.2/h). At 2048 m with placebo, mean (SD) SpO ₂ was 86% (3%) and mean (SD) AHI was 34.9/h (20.7/h) ( P < .001 for both comparisons). Compared with placebo, NOT increased SpO ₂ by a mean of 9 percentage points (95% CI, 8-11 percentage points; P < .001), decreased AHI by 19.7/h (95% CI, 11.4/h-27.9/h; P < .001), and improved subjective sleep quality measured on a visual analog scale by 9 percentage points (95% CI, 0-17 percentage points; P = .04). During visits to 2048 m or within 24 hours after descent, 8 patients (26%) using placebo and 1 (4%) using NOT experienced ARAHEs ( P < .001).

Conclusions and Relevance

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.

Trial Registration

ClinicalTrials.gov Identifier: NCT02150590