title: Nocturnal hypoventilation: predictors and outcomes in childhood progressive neuromuscular disease.
abstract: OBJECTIVE
  To determine: (a) prevalence of clinically unsuspected nocturnal hypoventilation (NH) in a clinic population of children with progressive neuromuscular disease; (b) whether NH can be predicted from clinical/laboratory parameters; and (c) change over 1 year in pulmonary function decline, quality of life and attention in children with NH treated with non-invasive positive pressure ventilation (NPPV) compared with children without NH.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  Two tertiary-care paediatric neuromuscular clinics.
  
  
  METHODS
  46 children (6-17 years) with progressive neuromuscular disease without neurocognitive impairment or dystrophinopathy.
  
  
  METHODS
  Polysomnography, pulmonary function, manual muscle strength, quality of life (CHQ-PF50) and Conners questionnaires.
  
  
  METHODS
  (a) Prevalence of NH; (b) predictive value of surrogate clinical measures for NH; and (c) differences in change over 1 year in pulmonary function, muscle strength, quality of life and attention between children with and without NH.
  
  
  RESULTS
  Prevalence of NH was 14.8%, 95% CI 8.0% to 25.7%. Maximal sensitivity and specificity for NH were achieved with thresholds of forced vital capacity <70% and forced expiratory volume in 1 s <65% predicted (sensitivities: 71.4, 71.4; specificities: 64.1, 79.5). Scoliosis also predicted NH (sensitivity 88.9; specificity 80.4). Over 1 year, those with NH had a greater increase in residual volume/total lung capacity (0.075 (-0.003 to 0.168) vs -0.03 (-0.065 to 0.028)), decline in muscle strength (-0.67 (-0.90 to 0.10) vs 0.53 (-0.05 to 0.90)) and worsened perception of health status.
  
  
  CONCLUSIONS
  15% of subjects had clinically unsuspected NH, predicted by moderate pulmonary function test impairment and scoliosis. Over 1 year those with NH had increased gas trapping, decline of muscle strength and worse perception of health status, despite NPPV.
authors.affiliation: Department of Pediatrics, Children's Hospital of Eastern Ontario, Ottawa, Canada. skatz@cheo.on.ca
authors.forename: Sherri L
authors.initials: SL
authors.lastname: Katz
authors.forename: Isabelle
authors.initials: I
authors.lastname: Gaboury
authors.forename: Krista
authors.initials: K
authors.lastname: Keilty
authors.forename: Brenda
authors.initials: B
authors.lastname: Banwell
authors.forename: Jiri
authors.initials: J
authors.lastname: Vajsar
authors.forename: Peter
authors.initials: P
authors.lastname: Anderson
authors.forename: Andy
authors.initials: A
authors.lastname: Ni
authors.forename: Ian
authors.initials: I
authors.lastname: Maclusky
mesh_terms: D000293:Adolescent; D002245:Carbon Dioxide / Q000502:physiology; D002648:Child; D018450:Disease Progression; D004812:Epidemiologic Methods; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D007040:Hypoventilation / Q000209:etiology* / Q000503:physiopathology; D008297:Male; D053580:Muscle Strength / Q000502:physiology; D009468:Neuromuscular Diseases / Q000150:complications* / Q000503:physiopathology; D017286:Polysomnography / Q000379:methods; D011379:Prognosis; D011788:Quality of Life; D012129:Respiratory Function Tests; D012600:Scoliosis / Q000150:complications; D014797:Vital Capacity
chemical_list: D002245:Carbon Dioxide