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. 2021 Jan 6;30(159):200187. doi: 10.1183/16000617.0187-2020

FIGURE 3.

FIGURE 3

Interpretation algorithm for cardiopulmonary exercise testing (CPET). This figure provides an outline of a CPET interpretation strategy. Importantly, the data obtained from a CPET test should not be interpreted in isolation, but rather should be integrated with other clinical findings/investigations. RER: respiratory exchange ratio; HR: heart rate; V′O2: oxygen uptake; EFL: expiratory flow limitation; IC: inspiratory capacity; V′E: minute ventilation; WR: work rate; VT: tidal volume; V′CO2: carbon dioxide output; VAS: visual analogue scale; BR: breathing reserve; RR: respiratory rate; VC: vital capacity; EILV: end-inspiratory lung volume; TLC: total lung capacity; VD: dead space volume; PA–aO2: alveolar–arterial oxygen tension difference; PaO2: arterial oxygen pressure; SpO2: pulse-oximeter oxygen saturation; PaCO2: arterial pressure of carbon dioxide; Pa–ETCO2: arterial to end-tidal carbon dioxide pressure difference.