Progression in the patient’s pulmonary function tests from 2010 to 2013. a) Forced vital capacity (FVC); b) total lung capacity (TLC); c) diffusing capacity of the lung for carbon monoxide (DLCO); d) 6-min walking distance (6MWD); and e) oxygen saturation (... Progression in the patient’s pulmonary function tests from 2010 to 2013. a) Forced vital capacity (FVC); b) total lung capacity (TLC); c) diffusing capacity of the lung for carbon monoxide (DLCO); d) 6-min walking distance (6MWD); and e) oxygen saturation (arrow indicates patient was receiving supplemental oxygen). Start: oxygen saturation at the beginning of the 6MWD; end: oxygen saturation at the end of the 6MWD. Michael Kreuter et al. Eur Respir Rev 2014;23:239-248 ©2014 by European Respiratory Society