title: Tidal changes in respiratory resistance are sensitive indicators of airway obstruction in children.
abstract: BACKGROUND
  Individual assessment of airway obstruction in preschool-age children requires sensitive and specific lung function methods with low demand of cooperation. Although the forced oscillation technique (FOT) is feasible in young children, conventional measurements of respiratory impedance (Zrs) have limited diagnostic power in individuals.
  
  
  OBJECTIVE
  To find descriptors of within-breath Zrs that are sensitive indicators of airway obstruction during tidal breathing in children.
  
  
  METHODS
  Zrs was measured with (i) a standard multifrequency FOT (4-26 Hz) to assess the mean values of resistance and reactance for whole breaths and (ii) a 10 Hz signal to track the within-breath changes. Various Zrs measures obtained in healthy children (n=75) and those with acute wheeze (n=31) were investigated with receiver operator characteristic (ROC) analysis. The cut-off values obtained for airway obstruction were then tested in children with recurrent wheeze (n=20) before and after administration of salbutamol.
  
  
  RESULTS
  The largest area under the ROC curve (0.95) was observed for the tidal changes of resistance between the zero-flow values (ΔR). The ΔR cut-off value of 1.42 hPa s/L detected airway obstruction with sensitivity of 92% and specificity of 89% in children with acute wheeze and distinguished children with recurrent wheeze (16/20 above the cut-off value) from healthy children (22/23 below the cut-off value). Furthermore, ΔR significantly decreased after salbutamol in wheezy children but remained unchanged in healthy children.
  
  
  CONCLUSIONS
  New lung function measure ΔR is able to detect airway obstruction with high sensitivity and specificity and is suitable for use in lung function testing in young children.
authors.affiliation: Children's Lung, Environment and Asthma Research Team, University of Queensland, Brisbane, Queensland, Australia Child Health Research Centre, University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Dorottya
authors.initials: D
authors.lastname: Czövek
authors.affiliation: Children's Lung, Environment and Asthma Research Team, University of Queensland, Brisbane, Queensland, Australia Child Health Research Centre, University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Claire
authors.initials: C
authors.lastname: Shackleton
authors.affiliation: Children's Lung, Environment and Asthma Research Team, University of Queensland, Brisbane, Queensland, Australia Child Health Research Centre, University of Queensland, Brisbane, Queensland, Australia Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary Department of Pulmonology, University of Szeged, Szeged, Hungary.
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Hantos
authors.affiliation: Children's Lung, Environment and Asthma Research Team, University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Kate
authors.initials: K
authors.lastname: Taylor
authors.affiliation: Children's Lung, Environment and Asthma Research Team, University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Anushma
authors.initials: A
authors.lastname: Kumar
authors.affiliation: Children's Lung, Environment and Asthma Research Team, University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Archana
authors.initials: A
authors.lastname: Chacko
authors.affiliation: Child Health Research Centre, University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Ware
authors.affiliation: Department of Technical Informatics, University of Szeged, Szeged, Hungary.
authors.forename: Gergely
authors.initials: G
authors.lastname: Makan
authors.affiliation: Department of Pulmonology, University of Szeged, Szeged, Hungary.
authors.forename: Bence
authors.initials: B
authors.lastname: Radics
authors.affiliation: Department of Technical Informatics, University of Szeged, Szeged, Hungary.
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Gingl
authors.affiliation: Children's Lung, Environment and Asthma Research Team, University of Queensland, Brisbane, Queensland, Australia Child Health Research Centre, University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Sly
mesh_terms: D000403:Airway Resistance / Q000187:drug effects / Q000502:physiology*; D000420:Albuterol / Q000494:pharmacology; D000886:Anthropometry / Q000379:methods; D001249:Asthma / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology; D001993:Bronchodilator Agents / Q000494:pharmacology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D008297:Male; D012372:ROC Curve; D012008:Recurrence; D012129:Respiratory Function Tests / Q000379:methods; D012135:Respiratory Sounds / Q000209:etiology / Q000503:physiopathology; D012680:Sensitivity and Specificity; D013990:Tidal Volume / Q000502:physiology*
chemical_list: D001993:Bronchodilator Agents; D000420:Albuterol
keywords: Paediatric asthma; Respiratory Measurement