2.3 Correction of signal processing in MBW
In brief, the sensor-crosstalk error in the Exhalyzer D device
underestimates O2 and CO2 gas
concentrations and thus overestimates end-expiratory concentrations of
N2. Elevated N2 concentrations cause a
significant overestimation of the main MBW outcomes FRC and LCI as well
as of the N2 back-diffusion from the lungs1. An updated Spiroware analysis software (v3.3.1, Eco
Medics AG, Duernten, Switzerland), will correct automatically for this
error. Previously reported results, however, need to be reanalyzed. In
this study, we reanalyzed raw data (A-Files) using LungSim 1.01, a
custom Python script developed by our group replicating the signal
processing and outcome calculation used in Spiroware analysis software
(v3.2.1 and 3.3.1) 1.
2.4 Re-assessment of clinimetric properties and
statistical analysis
We present non-parametric summaries for skewed data and parametric
summaries for normally distributed characteristics. Statistical analyses
were performed using Stata 16.1 (StataCorp 2019, College Station; TX).
Figures were created using Stata 16.1 or Graph Pad Prism 8 (Prism G
2018, La Jolla; California). The following clinimetric properties of LCI
were examined and compared between the Spiroware software versions 3.2.1
and 3.3.1: