Prognostic Value of Functional Exercise Test (EFX) in Cystic Fibrosis

The Cardiopulmonary exercise testing (CPET) was performed at the beginning of the study, the same at each center. Each patient underwent a symptom-limited incremental exercise test on an ergometric bicycle (Ergoline-Ergometrics 800®). The protocol included a warm-up period of 3 min at 20 W followed by a progressively increasing work rate (WR) in a ramp fashion and then 3 min recovery. The ramped WR increment was individualized (range,8-30 W/min). during exercise, heart rate (HR) was monitored continuously by 12-lead ECG, and arterial oxygen saturation (SpO2) was measured by pulse oximetry (Nellcor N-395). The expired gases were analyzed with an Ergocard®, focusing on oxygen consumption(VO2), carbon dioxide production (VCO2), minute ventilation (VE), and tidal volume (VT).