Table 2.
Comparison of sleep and acute mountain sickness data at an altitude of 2,750 m with and without positive airway pressure
| With PAP (n = 6) | Without PAP (n = 6) | P Value | |
|---|---|---|---|
| AHI, events/h | 11 (9–14.5) | 12.5 (5.5–40.8) | 0.44 |
| AHI non-REM, events/h | 8 (7–12.5) | 12.5 (4–41.3) | 0.95 |
| AHI REM, events/h | 28 (19.3–43.3) | 16.5 (0–37.3) | 0.53 |
| Central apnea index, events/h | 0 (0–1.8) | 1 (0.8–6.3) | 0.03 |
| Obstructive apnea index, events/h | 0 (0–1) | 1.5 (0–6.8) | 0.11 |
| Hypopnea index, events/h | 10.5 (8.3–13.5) | 11.5 (4.3–27.5) | 0.46 |
| Mean SpO2 (wake), % | 97 (94–98) | 96 (94–98) | 0.91 |
| Mean SpO2 (TST), % | 84 (85–90) | 85 (84–87) | 0.29 |
| Low SpO2 (TST), % | 77 (74–80) | 77 (73–79) | 0.51 |
| Total sleep time SpO2 < 90%, min | 100 (13–346) | 251 (160–285) | 0.35 |
| Total sleep time, min | 358 (311–401) | 292 (250–331) | 0.06 |
| Sleep efficiency, % | 77.5 (71–85.3) | 62.5 (50.3–77.8) | 0.04 |
| REM time, min | 27.8 (25.9–55) | 12.3 (0–30.6) | 0.06 |
| Non-REM time, min | 324 (284–358) | 277 (249–307) | 0.06 |
| REM percentage, % | 9 (7–12.5) | 4.5 (0–9.3) | 0.06 |
| Arousal index, 1/h | 10.5 (6.6–23) | 11.5 (6.3–25) | 0.60 |
| AMS score | 0.5 (0–1.5) | 3.5 (2.8–5.3) | 0.03 |
Definition of abbreviations: AHI = apnea–hypopnea index; AMS = acute mountain sickness; PAP = positive airway pressure; SpO2 = oxygen saturation as measured by pulse oximetry; TST = total sleep time.
Data are presented as median (quartiles).
Four patients without PAP received supplemental oxygen during sleep because of severe hypoxemia.