Assessment of within‐breath impulse oscillometry parameters in children with asthma

Abstract

Background: Impulse oscillometry (IOS) measures respiratory resistance and reactance during tidal breaths and is a convenient tool for evaluation of lung function. Respiratory resistance and reactance can be measured separately during inspiration and expiration (inspiratory-expiratory analysis).Objective: We investigated the differences in inspiratory-expiratory measurements obtained using IOS between children with and without asthma. Methods:We analyzed 819 subjects aged 4-18 years, including asthmatic children (n = 600) and controls (n = 219). Asthma was diagnosed in accordance with the American Thoracic Society/European Respiratory Society guideline. Spirometry and IOS were performed in all subjects.Results: In whole-breath analysis, the asthma group had higher resistance at 5 Hz (R5) and reactance area (AX) and lower reactance at 5 Hz (X5) than the control groups. In inspiratory-expiratory analysis, the asthma group showed increased expiratory R5 and AX and decreased expiratory X5 when compared with the control group. The absolute changes in R5, X5, and AX values between inspiration and expiration were greater in children with asthma than those in controls (0.138 ± 0.195 vs 0.102 ± 0.162, P = 0.014; −0.106 ± 0.200 vs −0.086 ± 0.434, P < 0.001 and 0.460 ± 11.63 vs 0.398 ± 2.88, P = 0.002, respectively).Conclusions: Inspiratory-expiratory IOS analysis differentiated asthmatic children from control subjects, reflecting airway narrowing on expiration in pediatric asthma.The changes in R5, X5, and AX between inspiration and expiration can be a useful index for diagnosis of asthma in children without assessment of the response to a bronchodilator. K E Y W O R D Sasthma, impulse oscillometry, within-breath analysis

Técnica De Oscilações Forçadas Na Avaliação E Manejo De Crianças Asmáticas: Uma Revisão Narrativa

“…Destes, (9) (69%) acrescentaram exames complementares sendo a espirometria o exame mais frequente. (1)(2)(3)(4)6,10,13,14,18) Quanto aos desfechos clínicos, cinco artigos (28%) abordaram alterações brônquicas, cinco (28%) investigaram possíveis discrepâncias entre a sensibilidade das medidas em diferentes equipamentos, bem como sua associação no estabelecimento do diagnóstico e, oito (44%) realizaram avaliações referentes a impedância pulmonar.…”

“…Os índices obtidos a partir desta análise contemplam R rs e X rs em várias frequências, permitindo avaliação de índices associados à resistência total, não homogeneidade e complacência dinâmica do sistema respiratório. (1)(2)(3)(4)6,8,(9)(10)(11)(12)14,16,18)…”

Impulse Oscillometric Evaluation of Airway Resistance in Overweight and Obese Children With Asthma

“…We found that the differences shown by spirometry in older age groups were not present in resistance and reactance values measured by IOS. IOS measures airway impedance, which is a function of resistance and reactance, thus predicts about the peripheral airway obstruction and detects inspiratory and expiratory changes in airway resistance in asthmatic children 7,18,19 .…”

Pediatric pulmonology year in review 2019: Physiology

“…Two studies focused on within‐breath versus whole breath analysis of IOS signals. Sol et al 8 hypothesized that analysis of inspiratory and expiratory IOS measurements would be more sensitive than whole‐breath analysis in differentiating lung function in children with asthma compared with those without asthma. Whole‐breath R5 and AX were significantly higher in asthmatic children compared with normal controls, while X5 was significantly lower.…”