Multiple-breath-washout
MBW measurements were performed with a flow, volume and molecular mass
measurement analyzer (EXHALYZER D, Ecomedics, Switzerland), according to
ERS/ATS Consensus Guidelines 27. A minimum of two
satisfactory LCI results were obtained for each patient. Normal cut-off
value of LCI was set at 7.81. Scond and Sacin, two MBW test secondary
indexes of conductive airways and acinar zone respectively, collected
during the measurements, were included in the analysis