title: Respiratory and polysomnographic values in 3- to 5-year-old normal children at higher altitude.
abstract: OBJECTIVE
  To determine polysomnographic parameter differences in children living at higher altitude to children living near sea level.
  
  
  METHODS
  Prospective study of non-snoring, normal children recruited from various communities around Denver, CO. In-lab, overnight polysomnograms were performed at a tertiary care children's hospital. All children required residence for greater than one year at an elevation around 1,600 meters.
  
  
  METHODS
  45 children (62% female), aged 3-5 years, 88.9% non-Hispanic white with average BMI percentile for age of 47.8% ± 30.7%.
  
  
  RESULTS
  Standard sleep indices were obtained and compared to previously published normative values in a similar population living near sea level (SLG). In the altitude group (AG), the apnea-hypopnea index was 1.8 ± 1.2 and the central apnea-hypopnea index was 1.7 ± 1.1, as compared to 0.9 ± 0.8 and 0.8 ± 0.7, respectively, (P ≤ 0.005) in SLG. Mean end-tidal CO2 level in AG was 42.3 ± 3.0 mm Hg and 40.6 ± 4.6 mm Hg in SLG (P = 0.049). The ≥ 4% desaturation index was 3.9 ± 2.0 in AG compared to 0.3 ± 0.4 in SLG (P < 0.001). Mean periodic limb movement in series index was 10.1 ± 12.3 in AG and 3.6 ± 5.4 in SLG (P = 0.001).
  
  
  CONCLUSIONS
  Comparison of altitude and sea level sleep studies in healthy children reveals significant differences in central apnea, apneahypopnea, desaturation, and periodic limb movement in series indices. Clinical providers should be aware of these differences when interpreting sleep studies and incorporate altitude-adjusted normative values in therapeutic-decision making algorithms.
authors.affiliation: University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, CO.
authors.forename: Casey J
authors.initials: CJ
authors.lastname: Burg
authors.forename: Hawley E
authors.initials: HE
authors.lastname: Montgomery-Downs
authors.forename: Pamela
authors.initials: P
authors.lastname: Mettler
authors.forename: David
authors.initials: D
authors.lastname: Gozal
authors.forename: Ann C
authors.initials: AC
authors.lastname: Halbower
mesh_terms: D000531:Altitude; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D017286:Polysomnography; D011446:Prospective Studies; D012016:Reference Values; D012119:Respiration; D012143:Respiratory Physiological Phenomena; D012890:Sleep / Q000502:physiology*; D012893:Sleep Wake Disorders / Q000503:physiopathology
keywords: Polysomnography; altitude; child; normal subjects; respiratory; sleep