Variability of peripheral airway resistance through impulse oscillometry in asthmatic children and adolescents / Variabilidade da resistência das vias aéreas periféricas através da oscilometria de impulso em crianças e adolescentes asmáticos

Introduction. The assessment of lung function in asthmatic patients is a procedure used for the diagnosis and monitoring of diseases. The impulse oscillometry system, a minimally invasive and collaborative method, allows the measurement through changes in resistance and reactance. The analysis of variability allows the identification of the quality and reproducibility of this method. Goal. To describe the behavior of the variability of impulse oscillometry parameters in asthmatic children and adolescents. Method. A quantitative descriptive cross-sectional study was carried out in the Allergy and Immunology sector of the Hospital das Clínicas of the Federal University of Pernambuco. The sample consisted of children and adolescents, of both sexes, diagnosed with asthma and rhinitis. Three measurements were taken and for each parameter the mean of the resistance values at the frequencies of 5Hz and 20Hz was calculated, and from these data the resistance of the peripheral pathways (R5-R20Hz), in addition to the elastance at 5Hz and the reactance area ( AX).. Results. Seventy children and adolescents, with 62% (43) male, and for the whole group, mean age of 11.22±3.23 years, mean weight of 44.21±16.15 kilograms and mean height of 150.28 ±17.07 centimeters. There was no significant variation in measurements between times. The measure of the intraclass correlation coefficient was 0.949, demonstrating a high correlation between the analyzed moments. Conclusion. The total airway resistance is one of the most used parameters to measure alterations in the tracheobronchial tree and the verification of the variability must remain equal to or less than 15%.