Lung Clearance Index (LCI) in Pediatric Patients With Obstructive Lung Disease

Subjects of all the intervention groups will perform three consecutive nitrogen multiple breath washout tests (N2-MBW-tests) when attending the Universitair Ziekenhuis Brussel (UZB) for their scheduled pulmonology consultation. Only the best measurement (based on LCI result) will be taken into account when comparing the groups. Every subject will be positioned in the same seated position.