title: Night-to-night variability of polysomnography in children with suspected obstructive sleep apnea.
abstract: OBJECTIVE
  To determine whether a single polysomnographic night was a valid measure of obstructive sleep apnea syndrome (OSAS) in children with symptoms of sleep-disordered breathing.
  
  
  METHODS
  The night-to-night variability of respiratory and sleep parameters was measured prospectively in 30 snoring children aged 1.6 to 11.3 years (mean +/- SD, 4.1 +/- 2) by using 2 nocturnal polysomnograms performed 7 to 27 days apart (14 +/- 5 days).
  
  
  RESULTS
  The mean of the respiratory variables including apnea index, apnea/hypopnea index, arterial oxygen saturation, and end-tidal partial pressure of carbon dioxide were not significantly different from night to night. Among the sleep parameters, there was no significant night-to-night difference in sleep efficiency, arousal index, percent rapid eye movement, or percent of slow wave sleep. Only the percentage of stage 2 was significantly different between the nights. The polysomnographic clinical diagnosis remained the same on both nights for all children, although the disease severity differed slightly in 2 patients.
  
  
  CONCLUSIONS
  There is little clinically significant night-to-night variability in pediatric polysomnography, and no first-night effect. These data suggest that a single polysomnographic night is an adequate measure of the OSAS in children with symptoms of sleep-disordered breathing.
authors.affiliation: Eudowood Divison of Pediatric Respiratory Sciences, Johns Hopkins University, Baltimore, Maryland, USA.
authors.forename: Eliot S
authors.initials: ES
authors.lastname: Katz
authors.forename: Mary G
authors.initials: MG
authors.lastname: Greene
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Carson
authors.forename: Patricia
authors.initials: P
authors.lastname: Galster
authors.forename: Gerald M
authors.initials: GM
authors.lastname: Loughlin
authors.forename: John
authors.initials: J
authors.lastname: Carroll
authors.forename: Carole L
authors.initials: CL
authors.lastname: Marcus
mesh_terms: D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D017286:Polysomnography / Q000379:methods*; D011446:Prospective Studies; D015203:Reproducibility of Results; D015656:Respiratory Mechanics; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis*; D012894:Sleep Stages; D018709:Statistics, Nonparametric