The treatment of obstructive sleep apnea (OSA) in highland residents is not established.Does nocturnal oxygen supplementation (NOS) improve sleep-related breathing disturbances, nocturnal oxygenation and cognitive performance in patients with OSA living at 3200 m?and Methods: 40 OSA patients permanently living in Shangri-La, China, at 3200m, median (quartiles) age 47.0 (44.0;53.0) years, oxygen desaturation index 38.4 (34.2;52.3)/h were randomly assigned to receive nasal NOS and sham oxygen (ambient air), respectively, during one night each, at 2 L/min, in a crossover design, separated by a washout period of two weeks. During treatment nights polysomnography was performed, further outcomes were evaluated in the next morning. The primary outcome was the difference in apnea-hypopnea index (AHI) between nights with NOS and sham oxygen.During nights with sham oxygen, median (quartiles) total AHI was 43.4 (31.1;67.5)/h, obstructive AHI 41.9 (28.5;66.8)/h, central AHI 0.6 (0.1;1.3)/h, pulse oximetry (SpO2) 87.0 (84.5;89.0)%. In intention-to-treat analysis, NOS decreased the total AHI by a median of 17.9/h (95%CI 8.0 to 27.1, P<0.001), through a reduction of obstructive AHI by 16.0/h (95%CI 6.8 to 26.0, P<0.001) and central AHI by 0.4/h (95%CI 0.1 to 0.9, P<0.001). NOS also increased SpO2 by 7.0% (95%CI 6.0 to 8.0, P<0.001). Heart rate during sleep and pulse rate in the morning after NOS were significantly reduced, but subjective sleep quality and cognitive performance showed no changes.In highland residents with OSA, NOS significantly improved sleep-related breathing disturbances and nocturnal oxygenation. NOS also reduced heart rate during sleep and morning pulse rate. If these beneficial effects are confirmed in longer-term studies, NOS may be a treatment option for highland OSA patients who cannot use CPAP.
Lu Tan, Taomei Li, Yanyan Zhang, Deping He, Lian Luo, Fei Lei, Rong Ren, Jiaming He, Konrad E Bloch, Xiangdong Tang