A protocol to determine valid in young cystic fibrosis patients

Objectives - Measuring aerobic fitness (View the MathML source) via a maximal cardiopulmonary exercise test is an important clinical tool in cystic fibrosis. This study sought to establish: (1) the validity of traditional criteria to verify maximal efforts during a ramp cardiopulmonary exercise test; and (2) whether View the MathML source measured during an exhaustive cardiopulmonary exercise test represents a valid View the MathML source in paediatric patients, using a subsequent exhaustive supramaximal (Smax) exercise test.

Design - Cross-sectional.

Methods - Fourteen patients (7–18 years; 10 males) completed an exhaustive ramp test to determine View the MathML source. Following 15-min recovery, Smax (110% ramp peak power output) was performed.

Results - Ramp test View the MathML source was significantly higher than View the MathML source documented at traditional endpoint criteria, including a RER of 1.00 (0.99 ± 0.47 L min−1 vs. 1.83 ± 0.78 L min−1, p < 0.001) and 1.10 (1.36 ± 0.59 L min−1 vs. 1.83 ± 0.78 L min−1, p < 0.001), despite 100% of patients satisfying these two criteria. Only 23% and 75% of patients satisfied the 95% age-predicted heart rate (HR) maximum and 180 b min−1 criteria. Whilst mean ramp and SmaxView the MathML source were not significantly different (1.83 ± 0.78 L min−1 vs. 1.82 ± 0.67 L min−1; p = 0.88), at the individual level Smax elicited a ‘meaningful’ (>9%) increase in View the MathML source (range 9.9–38.3%) compared with View the MathML source from the ramp test in 3 of 14 cases (21.4%).

Conclusions - Traditional criteria significantly underestimate View the MathML source in young cystic fibrosis patients. Conversely, Smax can confirm when ‘true’ View the MathML source is achieved. The use of Smax following cardiopulmonary exercise test represents an appropriate method to measure View the MathML source in young cystic fibrosis patients.