Periodic breathing and oxygen supplementation in Chilean miners at high altitude (4200m).

Our objective was to determine the nocturnal ventilatory pattern and characterize the effect of oxygen enrichment on nocturnal ventilatory pattern and sleep quality in miners exposed to intermittent hypobaric hypoxia at 4200m. A total of 16 acclimatized miners were studied. Nocturnal ventilatory pattern (plethysmographic inductance), arterial oxygen saturation and heart rate (pulse oximetry) were performed in 9/16 subjects. Sleep quality at high altitude was assessed by self-questionnaires in 16/16 subjects. All measurements were performed during at least 7h of sleep. Subjects were studied while sleeping at high altitude without (control, C) and with oxygen supplementation (FiO2=0.25, treated, T). Periodic breathing (%) C: 25±18 vs T: 6.6±5.6 (p<0.05), apneas index (no./h) C: 34.9±24.1 vs T: 8.5±6.8 (p<0.05); and sleep quality C: 17.8±3.4 vs T: 12.1±2.2 (p<0.0001) were evaluated. In conclusion, periodic breathing with apneas was present in miners exposed to high altitude for 1 to 4 years and was reduced by treatment with supplementary oxygen.