Normal values for respiratory sleep polygraphy in children aged 4 to 9 years at 2,560 m above sea level

Obstructive sleep apnea syndrome affects 1%-4% of all children worldwide. Currently, diagnosis of obstructive sleep apnea is based on sea-level guidelines, without taking into account the altitude at which the populations live. It has been shown that at 3,200 m of altitude there is an increase in obstructive events in healthy children aged 7 to 16 years; on the other hand, it is known that SpO₂ dispersion between individuals becomes wider as altitude increases, a phenomenon that is more marked during sleep. About 17 million Colombians live in regions between 2,500 m and 2,700 m, as do significant populations in other Latin American countries. This research aimed to characterize respiratory polygraphy sleep parameters in healthy, non-snoring children aged 4-9 years living at 2,560 m. We carried out home respiratory polygraphy in 32 children with a mean age of 6.2 years (range 4-9 years). The average recorded sleep time was 7.8 h, the median apnea-hypopnea index was 9.2/h, the obstructive apnea-hypopnea index had a median of 8.8/h (p5 4.2 to p95 17.9) and central apnea a median of 0.4/h. The median SpO₂ was 93% (p5 90.5 to p95 94) and transcutaneous CO₂ had a median of 39.4 mmHg (p531.7 to p95 42.3). The median oxygen desaturation index ≥ 3% was 11.2 and median oxygen desaturation index ≥ 4% was 3.9. Normal measurements for respiratory polygraphy obtained at sea level do not apply to children at altitude. If such guidelines are used, obstructive sleep apnea will be over-diagnosed, resulting in unnecessary adenotonsillectomies, among other interventions.