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Ann Am Thorac Soc. 2015 Jul;12(7):1072-8. doi: 10.1513/AnnalsATS.201411-506OC.

Effects of positive airway pressure on patients with obstructive sleep apnea during acute ascent to altitude.

Author information

1
1 Division of Pulmonary and Critical Care Medicine, University of Utah School of Medicine, Salt Lake City and.
2
2 Division of Pulmonary and Critical Care Medicine.
3
3 Division of Sleep Medicine, and.
4
4 Division of Hyperbaric Medicine, Intermountain Medical Center, Murray, Utah.

Abstract

RATIONALE:

In acute ascent to altitude, untreated obstructive sleep apnea (OSA) is often replaced with central sleep apnea (CSA). In patients with obstructive sleep apnea who travel to altitude, it is unknown whether their home positive airway pressure (PAP) settings are sufficient to treat their obstructive sleep apnea, or altitude-associated central sleep apnea.

METHODS:

Ten participants with positive airway pressure-treated obstructive sleep apnea, who reside at 1,320 m altitude, underwent polysomnography on their home positive airway pressure settings at 1,320 m and at a simulated altitude of 2,750 m in a hypobaric chamber. Six of the participants were subsequently studied without positive airway pressure at 2,750 m.

MEASUREMENTS AND MAIN RESULTS:

At 1,320 m, all participants' sleep apnea was controlled with positive airway pressure on home settings; at 2,750, no participants' sleep apnea was controlled. At higher altitude, the apnea-hypopnea index was higher (11 vs. 2 events/h; P < 0.01), mostly due to hypopneas (10.5 vs. 2 events/h; P < 0.01). Mean oxygen saturations were lower (88 vs. 93%; P < 0.01) and total sleep time was diminished (349 vs. 393 min; P = 0.03). Four of six participants without positive airway pressure at 2,750 m required supplemental oxygen to prevent sustained oxygen saturation (as determined by pulse oximetry) less than 80%. Positive airway pressure also was associated with reduced central sleep apnea (0 vs. 1; P = 0.03), improved sleep time (358 vs. 292 min; P = 0.06), and improved sleep efficiency (78 vs. 63%; P = 0.04).

CONCLUSIONS:

Acute altitude exposure in patients with obstructive sleep apnea treated with positive airway pressure is associated with hypoxemia, decreased sleep time, and increased frequency of hypopneas compared with baseline altitude. Application of positive airway pressure at altitude is associated with decreased central sleep apnea and increased sleep efficiency.

KEYWORDS:

altitude; mountain sickness; sleep apnea

PMID:
25884271
PMCID:
PMC4566407
DOI:
10.1513/AnnalsATS.201411-506OC
[Indexed for MEDLINE]
Free PMC Article

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