Clinical Bottom Line
“How can I apply this information in adolescents with cystic fibrosis in my clinical practice?”
Aerobic capacity and exercise testing are important tools within pediatric physical therapy practice, but often not a content area of comfort for the practicing pediatric physical therapist. Whereas cystic fibrosis (CF), a common pediatric disorder, requires a multidisciplinary approach, exercise testing and training, which has a critical role in the management of adolescents with CF, has received little attention. Studies have shown that higher peak VO2 and the time-dependent decline in peak VO2 assist in predicting survival in CF.1,2 Additionally, exercise training has been shown to improve aerobic fitness and is an important adjunct for mucociliary clearance.3-5 Physical therapists must continue to develop their expertise in the area of exercise testing and training, and this article describes a relatively simple means of determining exercise capacity in adolescents with CF. The accurate determination of
O2 peak is critical in exercise testing and exercise prescription, yet the inconsistency between heart rate and VO2 raises some concerns that are addressed by this study. This study clarifies that
O2 peak measured by traditional exercise testing does appear to reflect the true
“What should I be mindful about in applying this information?”
Pediatric therapists must continue to develop competence and expertise in the area of aerobic capacity and exercise testing. Clearly the authors are experienced with the technical aspects of exercise testing and metabolic analysis. This study specifically focused on stable adolescents with mild to moderate involvement. The clinician must be cautious to not generalize the findings to patients in other age groups or with different disease severities, including those with exercise induced hypoxemia, dysrhythmias, or patients being treated for a CF exacerbation. Whereas it is tempting to use the Steep Ramp test (SRT) as a measure of exercise capacity, additional validation of the SRT must be completed as noted by the authors. Until then, standard cardiopulmonary exercise testing (CPET) based on heart rate and work load increments should remain the standard of care.
1. Nixon PA, Orenstein DM, Kelsey SF, Doershuk CF. The prognostic value of exercise testing in patients with cystic fibrosis. N Engl J Med. 1992;327(25):1785–1788.
2. Pianosi P, LeBlanc J, Almudevar A. Peak oxygen uptake and mortality in children with cystic fibrosis. Thorax. 2005;60(1):50–54.
3. Orenstein DM, Franklin BA, Doershuk CF, et al.. Exercise conditioning and cardiopulmonary fitness in cystic fibrosis: the effects of a three-month supervised running program. Chest. 1981;80:392–398.
4. Salh W, Bilton D, Dodd M, et al.. Effect of exercise and physiotherapy in aiding sputum expectoration in adults with cystic fibrosis. Thorax. 1989;44:1006–1008.
5. Edlund LD, French RW, Herbst JJ, et al.. Effects of a swimming program on children with cystic fibrosis. Am J Dis Child. 1986;140:80–83.