title: Spirometry and forced oscillations in the detection of airway hyperreactivity in asthmatic children.
abstract: BACKGROUND
  Provocation tests are routinely used to detect airway hyperreactivity (AH) in the diagnosis of asthma. We compared the sensitivities of the forced oscillation technique (FOT) and spirometry in the detection of AH in asthmatic children.
  
  
  METHODS
  FOT and spirometry were performed in 20 asthmatic children (aged 5-18 years) following aerosolized histamine and methacholine at an interval of 2 weeks. The respiratory system input impedance was measured by FOT; the resistance at 6 Hz (R(6) ), the average resistance between 4 and 24 Hz, the area under the reactance curve (AX) and the resonant frequency were extracted from these recordings. Spirometry was used to obtain forced expiratory volumes and flow parameters.
  
  
  RESULTS
  Following provocation with the two agonists, the FOT detected the airway response as early as spirometry. When the greater variability of the impedance parameters was taken into account, the two methods were observed to have similar sensitivities. Among the lung function parameters studied, AX and R(6) were the most sensitive for the demonstration of AH.
  
  
  CONCLUSIONS
  Our findings demonstrate that FOT is as suitable as spirometry for the measurement of bronchoconstriction and thus it may be considered for the detection of AH in asthmatic children. Since its application requires minimal cooperation, this approach imposes less stress and may be particularly favorable in the diagnosis of asthma at a young age.
authors.affiliation: Department of Medical Physics and Informatics, University of Szeged, Hungary. petak@dmi.szote.u-szeged.hu
authors.forename: Ferenc
authors.initials: F
authors.lastname: Peták
authors.forename: Dorottya
authors.initials: D
authors.lastname: Czövek
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Novák
mesh_terms: D000293:Adolescent; D000403:Airway Resistance / Q000502:physiology; D001249:Asthma / Q000503:physiopathology*; D016535:Bronchial Hyperreactivity / Q000175:diagnosis* / Q000503:physiopathology; D016084:Bronchoconstriction / Q000502:physiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006632:Histamine; D006801:Humans; D008297:Male; D016210:Methacholine Chloride; D009991:Oscillometry / Q000379:methods*; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013147:Spirometry / Q000379:methods*
chemical_list: D016210:Methacholine Chloride; D006632:Histamine