Real‐life application of respiratory oscillometry in pediatric asthma outpatient care: Feasibility and methodological aspects

Asthma diagnosis can be challenging in children. Spirometry is highly effort-dependent and often normal in early disease. Forced oscillation technique (FOT) is an alternative to spirometry and is performed during tidal breathing. We investigated the feasibility of FOT with fewer acquisitions than suggested by technical standards in a pediatric outpatient care setting. We also studied the influence of tidal breathing patterns on FOT indices. Finally, the clinical utility of FOT was compared with spirometry. Ninety-five children aged 3-12 years performed FOT with single-frequency mode of 8 Hz (Resmon Pro, ResTech, Italy) during initial asthma assessment or follow-up. School-aged children (n = 61) also performed spirometry. In preschool age (<6 years), 94% managed one and 74% managed two approved FOT acquisitions, whereas in school-age 100% and 92% managed correspondingly. Reasonable agreement between two device-approved FOT measurements was found. No difference in FOT values was found with spontaneous higher respiratory rates or tidal volumes. Bronchodilation responses measured with FOT, but not spirometry, were associated with ongoing anti-inflammatory asthma medication. FOT with an integrated quality control was highly feasible in children 3-12 years. Reasonable agreement between two device-approved acquisitions was found suggesting one measurement might suffice. Deviations from normal tidal breathing had little influence on FOT results.