[Periodic breathing during sleep at high altitudes in patients with bronchial asthma]. / Oddychanie okresowe w czasie snu w wysokich górach u chorych na astme oskrzelowa.

Earlier we found that asthmatic patients treated at a high altitude sanatorium (3.200 m) had numerous episodes of arterial blood desaturation during the night. To investigate if periodic breathing (PB) was responsible for those episode we studied 5 asthmatics (A) (mean age 34 yrs) and 3 healthy controls (C) (mean age 28 yrs) using MESAM 4, a simple, portable system recording breathing sounds, heart frequency, arterial blood saturation and body position. A and C subjects were first investigated at low altitude (760 m). There was no PB at 760 m in either group. At high altitude MESAM 4 recordings were performed on the 2nd and the 7th night after the ascent. On the 2nd night in the A group subjects the number of PB cycles averaged 37.2 (22-54) occupying 3.2% (2-5%) of estimated sleep time. The number of no-PB episodes was 52.4 (23-109). In the C group subjects the number of PB cycles was 83.6 (10-147) occupying 9% (1-14%) of estimated sleep time. The number of no-PB episodes averaged 45.6 (6-84). On the 7th night in A the number of PB cycles was 46.6 (15-69) occupying 4% (1-7%) of estimated sleep time. The number of no-PB was 54.8 (13-147). In C the number of PB cycles averaged 29.3 (12-59) occupying 3.3% (2-6%) of estimated sleep time. The number of no-PB was 20.3 (9-37). We conclude that majority of desaturations during sleep in asthmatics at altitude of 3.200 m was not related to PB; the mechanisms of these desaturations require more investigations.

[Effect of altitude on blood oxygenation during sleep in patients with bronchial asthma]. / Wplyw wysokosci na utlenowanie krwi w czasie snu u chorych na astme oskrzelowa.

The aim of our study was to investigate the severity of overnight arterial blood desaturations in patients with asthma at the altitude of 3200 meters above sea level. 12 asthmatics and 12 healthy controls were investigated. Three overnight pulsoximetries were performed in all subjects, one at the lowland and on the 1st and 5th night at the altitude. Mean SaO2 at the lowland was significantly lower in asthmatics than in the controls (p < 0.01). After the ascent to high altitude severe fall in mean SaO2 was noted in both groups (from 94.3% to 85.8% in asthmatics and from 97.1% to 88.7% in controls) (p < 0.001 for both groups). After few days of acclimatization mean SaO2 rose to 88.8% in asthmatics and to 91.3% in controls, but was still significantly lower than at the lowland (p < 0.001 for both groups). At the altitude differences in mean SaO2 between two groups were not statistically significant. We conclude that severity of overnight desaturations at high altitude do not vary between asthmatics with impaired respiratory function and healthy subjects.