Feasibility of multiple-breath washout in the clinical setting and prediction of its duration in children and adults with cystic fibrosis

Science and Research

BACKGROUND: Pulmonary function tests play an important role in diagnosis, management and treatment of people with cystic fibrosis (pwCF). Multiple-breath washout (MBW) is a sensitive method to detect ventilation inhomogeneities and is established in children with CF. Despite promising data in adults with pulmonary diseases, its feasibility remains questioned in adults due to longer examination times and limited added value over spirometry. We aimed to analyse feasibility of MBW in pwCF and healthy controls (HC) and evaluate factors influencing test duration. METHODS: We analysed 1,395 MBW measurements from pwCF (n = 1,158) and HC (n = 237). PwCF were divided according to percent predicted forced expiratory volume in one second (ppFEV(1); high, >90 %; mid, 40-90 %; low, <40 %) and age groups. Test feasibility was defined as two acceptable trials. The impact of constitutional and disease severity factors was analysed. RESULTS: Test feasibility was 100.0 % in HC and 94.3 % in pwCF, with higher feasibility in children than adults (96.0 % vs. 92.5 %, p = 0.01), and in those pwCF with higher ppFEV(1) (high, 96.6 %; mid, 94.9 %; low, 82.6 %; p < 0.001). The higher the ppFEV(1), the larger is the influence of constitutional factors over the impact of disease severity on trial time. Mean single trial time was 2.0 min, 2.7 min respectively 5.2 min in high, mid and low ppFEV(1). CONCLUSION: This study suggests extending MBW to adults with CF. Despite concerns about time efficiency, this study shows a good feasibility of MBW (92.5 %) in adults. Based on correlating factors, this study provides a decision-making tool for clinicians forecasting trial time.