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Small airway oscillometry indices: Repeatability and bronchodilator responsiveness in young children
Author(s) -
Knihtilä Hanna,
KotaniemiSyrjänen Anne,
Pelkonen Anna S.,
Kalliola Satu,
Mäkelä Mika J.,
Malmberg Leo Pekka
Publication year - 2017
Publication title -
pediatric pulmonology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.866
H-Index - 106
eISSN - 1099-0496
pISSN - 8755-6863
DOI - 10.1002/ppul.23794
Subject(s) - medicine , cutoff , bronchodilator , repeatability , percentile , placebo , confidence interval , salbutamol , asthma , area under the curve , anesthesia , cardiology , statistics , mathematics , pathology , physics , alternative medicine , quantum mechanics
Abstract Introduction The impulse oscillometry (IOS) indices absolute and relative difference between respiratory resistance at 5 and 20 Hz (R5‐20 and R5‐20%, respectively) and the area under the reactance curve (AX) are postulated to reflect small airway function. Data on their cutoff values to evaluate bronchodilator responsiveness (BDR) or between‐visit changes after interventions are limited in young children. Methods We evaluated the BDR of 103 healthy children aged 2‐7 years, who received either salbutamol ( n = 84) or placebo ( n = 19) in order to determine cutoff values for BDR of R5‐20, R5‐20%, and AX. We then determined the repeatability within and between two IOS measurements 7‐14 days apart in young children aged 4‐8 years with asthmatic symptoms ( n = 43), including cutoff values for significant between‐visit changes. Results The investigated IOS parameters showed marked BDR (fifth percentile cutoff of 75‐110% of the baseline value) in healthy children, whereas no significant changes were seen after inhalation of placebo. The agreement within the triplicate IOS measurement was excellent (ICC > 0.80), and the agreement of results between visits was good (ICC > 0.60). A change in R5‐20, R5‐20%, and AX of 0.65, 1.08, and 0.84 z ‐scores, respectively, would exceed 95% confidence intervals for between‐visit variability. Conclusion We introduce cutoff values for BDR of R5‐20, R5‐20%, and AX, and their repeatability indices and cutoff limits for significant between‐visit changes. These IOS parameters may show greater variability than the conventional IOS indices during follow‐up, but the between‐visit agreement remains good, providing potentially useful endpoints for monitoring lung function in young children.