Diffusion Capacity of Carbon Monoxide (DLCO) Pre- and Post-Exercise in Children in Health and Disease

Rationale: A decrease in diffusion capacity for carbon monoxide (DLCO) after exercise has been reported in healthy adults. There is limited information for post-exercise DLCO available in children either in health or in disease. Objectives: To evaluate (1) reproducibility of DLCO measures in children, (2) differences in DLCO between elite athletic swimmers (AS), stable cystic fibrosis patients (CF), and healthy controls (Con) at rest; and (3) after a maximal treadmill exercise test. Methods: Participants performed spirometry and DLCO at baseline, a maximal treadmill exercise test and repeated DLCO measures for 2 hr after cessation of exercise. Results: The mean (SD) coefficient of variation between baseline DLCO tests was 2.49% (1.86%). In girls, the mean baseline DLCO (ml/min/mmHg) was 18.61 (4.15) in CF, 22.32 (4.79) in controls and 27.18 (5.33) in AS. In boys: 23.68 (5.31) in CF, 28.09 (9.95) in controls and 37.75 (9.46) in AS. Baseline DLCO was significantly higher in AS than in CF patients (P<0.01). In girls post-exercise, the greatest mean decrease in DLCO from baseline was -7.50% to -12.83% and in boys -6.92% to -17.71%. The decline in DLCO was less important in the athletes than the other groups (P<0.05). Conclusions: DLCO is highly repeatable in children. AS have an increased DLCO at rest compared to both children with CF and controls. There is a decline from baseline to post-exercise DLCO and while there are disease-specific differences, the general pattern of change in DLCO measures after exercise is similar in children to adults. (C) 2013 Wiley Periodicals, Inc.