title: Gas trapping is associated with severe exacerbation in asthmatic children.
abstract: BACKGROUND
  Gas trapping suggesting small airway disease is observed in adult asthmatic suffering from severe asthma. The aim of the study was to assess whether gas trapping could be evidenced in asthmatic children with/without severe exacerbation and with/without symptoms during the past three months.
  
  
  METHODS
  Forced expiratory flows (FEV(1), FVC, MEF(25-75%), MEF(50%)), plethysmographic lung volumes (TLC, FRC, RV) before and after bronchodilation (BD) were recorded in asthmatic children with documented airflow reversibility. Three groups were defined according to the presence during the last three months of 1) severe exacerbation (oral steroid: 3 consecutive days) 2) asthma symptoms without severe exacerbation and 3) without any symptom (GINA guidelines).
  
  
  RESULTS
  180 children (median 11.3 years, range 6.3-17.6, 57 girls) were included, 24 (13%) had at least one severe exacerbation, 58 (33%) had respiratory symptoms without severe exacerbation and 98 (54%) had no symptom during the past 3 months. Forced expiratory flows did not significantly differ in these three groups, while RV/TLC was significantly higher in the first group before and even after bronchodilation: before BD, 0.27 +/- 0.07, 0.24 +/- 0.05 and 0.23 +/- 0.05, respectively (p = 0.016) and after BD, 0.25 +/- 0.07, 0.21 +/- 0.05, 0.21 +/- 0.05, respectively (p = 0.003).
  
  
  CONCLUSIONS
  In asthmatic children, gas trapping is associated with occurrence of a severe exacerbation during the last three months, suggesting a small airway disease that is not evidenced by forced expiratory flows.
authors.affiliation: Cabinet La Berma, 4 avenue de la Providence, 92 160 Antony, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Mahut
authors.forename: Claudine
authors.initials: C
authors.lastname: Peiffer
authors.forename: Plamen
authors.initials: P
authors.lastname: Bokov
authors.forename: Nicole
authors.initials: N
authors.lastname: Beydon
authors.forename: Christophe
authors.initials: C
authors.lastname: Delclaux
mesh_terms: D000293:Adolescent; D001249:Asthma / Q000175:diagnosis / Q000503:physiopathology*; D002648:Child; D018450:Disease Progression; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D005652:Functional Residual Capacity / Q000502:physiology; D006801:Humans; D008297:Male; D012129:Respiratory Function Tests