used as field test to assess exercise-induced oxygen desaturation (Andrianopoulos et al., 2014; Poulain et al., 2003) which has
an additional prognostic value besides the 6-min walk distance
(6MWD) (Andrianopoulos et al., 2015; Casanova et al., 2008). Also,
transcutaneouscarbon-dioxidepressure(TCPCO2)canbemeasured
reliably as an indicator of ventilatory adequacy and may be of clinical relevance in patients with COPD