Spirometric and structured light plethysmography derived measures of airflow obstruction in asthma

Introduction: Accurate diagnosis and monitoring of respiratory disease are important for breathing assessment. Conventional lung function techniques such as spirometry are challenging in young children, requiring their full cooperation. Structured Light Plethysmography (SLP) derives tidal breathing measures from thoraco-abdominal (TA) displacement in a non-contact environment. We have shown that IE50 SLP (ratio of inspiratory to expiratory TA displacement rate at 50% of TA displacement) measured by SLP is greater in asthmatic children with airflow obstruction than in healthy children (Hmeidi, H. et al., American Thoracic Society conf. proc. 2016; p10749). Aims: To examine the relationship between SLP-derived breathing parameters and parameters measured using conventional spirometry in children with asthma. Methods: Thirty stable asthmatic children (13 female, 7-16 years), with an FEV1% of SLP and FEV1% was examined using Spearman9s Rho test. Results: A correlation of -0.49 was found betweenIE50 SLP and FEV1% (p=0.005). Conclusion: We have shown that SLP can obtain objective measures of tidal breathing in children with asthma, and that IE50 SLP correlates well with FEV1% measured using spirometry. This novel parameter could be used to quantify the degree of airway obstruction.