Measurement of FEV1 reflects conductive / resistive
properties of the large airways (20), FVC is related to
the contractility of the expiratory muscles and MVV
is correlated with the respiratory muscle performance
(20). All the volumes were reported in BTPS (Body
Temperature and Pressure Saturated (21). ECCS set
of equations were used by Spirolab III to calculate
the predicted / reference values according to the ERS
guidelines (21).