2.2 MBW measurements
N2-MBW tests were performed using the Exhalyzer D device
and Spiroware analysis software (v3.2.1, Eco Medics AG, Duernten,
Switzerland) with weight-adjusted dead spaces and settings according to
current consensus guidelines 13,14. Testing was
performed with patients sitting upright and breathing through a
mouthpiece. Quality control was performed according to current
guidelines and tests with at least two acceptable MBW trials were
included in our analysis 14-16.