How to treat patients with obstructive sleep apnea syndrome during an altitude sojourn.

Considering the high prevalence of the obstructive sleep apnea syndrome (OSA), it is expected that many patients with the disorder are traveling to altitude. However, this may expose them to the risk of pronounced hypoxemia, exacerbation of nocturnal breathing disturbances by frequent central apneas, impaired daytime performance, and high blood pressure. Recently, randomized studies specifically investigated the effects of altitude (1630-2590 m) in OSA patients and the optimal treatment in this setting. The results indicate that patients should continue to use continuous positive airway pressure therapy (CPAP) when sleeping at altitude. Since CPAP alone does not control central sleep apnea emerging at altitude, combined treatment with acetazolamide and CPAP should be considered, in particular, in patients with severe OSA and co-morbidities. Supplemental oxygen combined with CPAP might be advantageous in patients with OSA and concomitant cardiopulmonary disease by preventing hypoxemia and central sleep apnea. In patients unable to use CPAP or if electrical power is not available, an optimally fitted mandibular advancement device might be an alternative treatment option that can be combined with acetazolamide during altitude sojourns. Acetazolamide alone is also beneficial and better than no treatment at all, since it improves oxygen saturation, breathing disturbances, and the excessive blood pressure elevation in OSA patients traveling to altitude.