Reproducibility of maximal cardiopulmonary exercise testing for young cystic fibrosis patients

BackgroundThe reproducibility of cardiopulmonary exercise testing (CPET) has not been established in young cystic fibrosis (CF) patients using a valid protocol.MethodsThirteen 7-18 year olds completed three CPETs, separated by 48 h and 4-6 weeks. CPET involved a ramp-incremental cycling test with supramaximal verification.ResultsMaximal oxygen uptake was repeatedly determined with no learning effect and typical errors expressed as a coefficient of variation (TECV%) of 9.3% (48 h) and 13.3% (4-6 weeks). The reproducibility of additional parameters of aerobic function [gas exchange threshold (TECV%: 11.2%, 16.8%); V˙O2 mean response time (TECV%: 37.8%, 89.4%); V˙O2 gain (TECV%: 17.4%, 24.5%)] and clinical utility [e.g. SaO2% (TECV%: 2.2%, 3.1%); ventilatory drive (V˙E/V˙CO2-slope) (TECV%: 7.8%, 17.7%)] was also established over the short- and the medium-term, respectively.ConclusionThese results establish limits of variability to determine meaningful changes over the short- and the medium-term for CPET outcomes in young CF patients.