title: Interrupter resistance in preschool children: measurement characteristics and reference values.
abstract: There is a need for quick, reliable, and noninvasive lung function tests to assess airway obstruction in preschool children both for pediatric pulmonary care as well as for research purposes. We studied feasibility, reproducibility, and validity of measurements of the respiratory system using the interrupter technique (interrupter resistance [Rint]) and obtained reference values in children from a general population, 2 to 7 yr of age. Accuracy was studied by comparisons of Rint with plethysmographic airway resistance (Raw) in 20 patients (7 to 14 yr) with mild to severe chronic airways obstruction and was satisfactory in patients with FEV(1) > 60% predicted. The technique proved sensitive enough to detect changes in airway caliber within a small group of 12 children who developed mild respiratory tract infections. Among children from a general population, subgroups with mild respiratory symptoms or mild respiratory disease had higher mean Rint values. Airway obstruction was better detected using expiratory rather than inspiratory interruptions, both programmed at peak tidal ventilatory flow. Reproducibility within subjects was satisfactory (intraclass correlation 0.82 and 0.79). The same applied to interobserver agreement (intraclass correlation 0.98). The interrupter technique proves to be a reliable and practical test of airway function, suitable for clinical and epidemiologic studies in preschool children.
authors.affiliation: Department of Paediatrics, Subdivision of Respiratory Medicine, Sophia Children's Hospital, Erasmus University and University Hospital, Dr Molewaterplein 60, 3015 GJ Rotterdam, The Netherlands. merkus@alkg.azr.nl
authors.forename: P J
authors.initials: PJ
authors.lastname: Merkus
authors.forename: J Y
authors.initials: JY
authors.lastname: Mijnsbergen
authors.forename: W C
authors.initials: WC
authors.lastname: Hop
authors.forename: J C
authors.initials: JC
authors.lastname: de Jongste
mesh_terms: D000367:Age Factors; D000402:Airway Obstruction / Q000145:classification / Q000175:diagnosis* / Q000209:etiology; D000403:Airway Resistance; D001249:Asthma / Q000150:complications; D001827:Body Height; D002648:Child; D002675:Child, Preschool; D005240:Feasibility Studies; D005541:Forced Expiratory Volume; D006801:Humans; D008403:Mass Screening / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D015588:Observer Variation; D010991:Plethysmography / Q000592:standards; D012016:Reference Values; D012044:Regression Analysis; D012220:Rhinitis / Q000150:complications; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D013990:Tidal Volume