Cardiopulmonary Exercise Testing in Children and Adolescents With Asthma Who Report Symptoms of Exercise-Induced Bronchoconstriction

Abstract

Joyner BL, Fiorino EK, Matta-Arroyo E, Needleman JP. J Asthma. 2006;43:675–678 PURPOSE OF THE STUDY. To use cardiopulmonary exercise testing (CPET) to establish the cause of exercise limitation in a population of children with asthma who were reporting symptoms of exercise-induced bronchoconstriction (EIB). STUDY POPULATION. A total of 42 children (aged 7 to 19 years) who continued to report exercise-associated symptoms attributed to asthma despite daily controller therapy were included in the study. There were 22 boys and 20 girls. All patients were receiving daily inhaled corticosteroids and had normal pulmonary function at the time of the study. Patients were excluded if they had underlying cardiac disease, had another chronic lung disease, or were unable to ride the cycle ergometer. METHODS. Each patient's BMI was calculated, and baseline spirometry was performed. Then, the patients performed cycle ergometry with a ramp protocol to voluntary exhaustion to determine maximal oxygen consumption (V̇o2). Spirometry was repeated at intervals of 5 and 20 minutes. A decrease of 10% in forced expiratory volume in 1 second was considered a positive finding of EIB. RESULTS. Ten patients (24%) developed EIB after CPET. There were no significant differences in BMI, BMI z score, V̇o2, or initial pulmonary function between the subjects who developed EIB and those who did not. CONCLUSIONS. Exercise limitation without EIB was found in both obese and nonobese patients, suggesting that poor fitness is a problem independent of body habitus. Including CPET in the management of children with suspected EIB would provide a better understanding of the etiology of their symptoms and facilitate more appropriate treatment. REVIEWER COMMENTS. This study illustrates how a patient's BMI does not directly correlate with fitness levels. Nonobese individuals can be just as out of shape as obese individuals. Given the trend toward more obesity in this country, it is important to not let any generalizations based on body habitus affect our judgment as physicians. Therefore, when a nonobese individual presents with symptoms similar to EIB, it may be prudent to have them undergo CPET before labeling them as asthmatic.