Longitudinal respiratory impedance in wheezy preschool children using intra-breath oscillometry

Abstract

Introduction/Aim: Low lung function in early life and poor lung function growth in the preschool years is associated with a higher risk of persistent asthma. This study evaluates the clinical utility of intra-breath oscillometry (IB-OSC) to detect airway obstruction in preschool-aged children with recurrent wheeze. Methods: Intra-breath respiratory impedance was measured by IB-OSC using a single 10 Hz sinusoid in children 3-6 years old presenting to the emergency department at the Queensland Children's Hospital with an acute wheezy illness. Children were eligible if they had a history of recurrent wheeze or asthma. Subjects were followed up for 12 months with subsequent IB-OSC performed when children were clinically well (3 weeks, 6 weeks, 6 months and 12 months) and if they represented to hospital (unscheduled visit). Airway obstruction was defined as a volume dependence of resistance (δR) ≥1.42 hPa × s × L -1 . Results: Eighty wheezy children (48 males) with median (IQR) age 4.6 (3.9, 5.7) years have been recruited with 91.5% of children able to produce acceptable IB-OSC measurements on the first attempt. The feasibility of IB-OSC was 98.2% across all visits. Despite resolution of clinical symptoms, many children had IB-OSC evidence of ongoing airway obstruction 6 weeks after hospital presentation (Figure 1). Conclusion: Preschool children with recurrent wheeze may have persistent, subclinical airway obstruction that can be detected by IB-OSC. With high feasibility in lung function naïve children, IB-OSC may be useful to longitudinally track lung function abnormalities in preschool children and identify those at risk of persistent asthma.