Tidal breathing parameters measured by structured light plethysmography in children aged 2-12years recovering from acute asthma/wheeze compared with healthy children

Measurement of lung function can be difficult in young children. Structured light plethysmography (SLP) is a novel, noncontact method of measuring tidal breathing that monitors displacement of the thoraco-abdominal wall. SLP was used to compare breathing in children recovering from an acute exacerbation of asthma/wheeze and an age-matched cohort of controls. Children aged 2-12years with acute asthma/wheeze (n=39) underwent two 5-min SLP assessments, one before bronchodilator treatment and one after. SLP was performed once in controls (n=54). Nonparametric comparisons of patients to healthy children and of pre-bronchodilator to post-bronchodilator were made for all children, and also stratified by age group (2-5 vs. 6-12years old). In the asthma/wheeze group, IE50(SLP) (inspiratory to expiratory flow ratio) was higher (median 1.47 vs. 1.31; P=0.002), thoraco-abdominal asynchrony (TAA) and left-right asynchrony were greater (both P<0.001), and respiratory rate was faster (P<0.001) than in controls. All other timing indices were shorter and displayed reduced variability (all P<0.001). Variability in time to peak inspiratory flow was also reduced (P<0.001). Younger children showed a greater effect than older children for TAA (interaction P<0.05). After bronchodilator treatment, the overall cohort showed a reduction in within-subject variability in time to peak expiratory flow only (P<0.001). Younger children exhibited a reduction in relative contribution of the thorax, TAA, and variability in TAA (interaction P<0.05). SLP can be successfully performed in young children. The potential of SLP to monitor diseases such as asthma in children is worthy of further investigation. ClinicalTrials.gov identifier: NCT02543333.