Browsing by Author "Knihtilä, Hanna"

Background: Early origins of chronic obstructive pulmonary disease have been recognized. Impulse oscillometry (IOS) is postulated to enable assessment of small airways function but limited data exist on the determinants of these proposed small airway indices, and on their sensitivity to detect lung function deficits in young children. Methods: IOS measurements of 103 healthy Finnish preschool children were evaluated to establish reference equations for the difference between respiratory resistance at 5 and 20 Hz (R5-20), the relative difference of R5-20 (R5-20%), and area under the reactance curve (AX). Thereafter, IOS results of young children with current troublesome lung symptoms (n=20), history of early wheeze (n=38), or bronchopulmonary dysplasia (BPD) (n=8) were compared to those of healthy children. Results: Height was the best independent determinant for reference equations of R5-20 (r=-0.417), R5-20% (r=-0.236), and AX (r=-0.678). R5-20 and R5-20% also showed variability with gender (p<0.05). Z-scores of R5-20, R5-20%, and AX appeared significantly higher in symptomatic than in healthy children (p<0.001), whereas respiratory resistance and reactance at 5 Hz (R5 and X5) differed from healthy only in children with history of BPD. Conclusions: R5-20, R5-20%, and AX are superior to conventional IOS parameters in distinguishing symptomatic children from the healthy ones. These parameters may prove valuable for screening early lung function deficits.