title: Diffusion capacity of carbon monoxide (DLCO) pre- and post-exercise in children in health and disease.
abstract: BACKGROUND
  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.
  
  
  OBJECTIVE
  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) co-efficient 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.
authors.affiliation: University of New South Wales, Sydney, Australia; Department of Respiratory Medicine, The Children's Hospital at Westmead, Sydney, Australia.
authors.forename: Nicholas M
authors.initials: NM
authors.lastname: Fitzgerald
authors.forename: Brendan
authors.initials: B
authors.lastname: Kennedy
authors.forename: Dominic A
authors.initials: DA
authors.lastname: Fitzgerald
authors.forename: Hiran
authors.initials: H
authors.lastname: Selvadurai
mesh_terms: D000293:Adolescent; D056352:Athletes; D001944:Breath Tests; D002248:Carbon Monoxide / Q000378:metabolism; D016022:Case-Control Studies; D002648:Child; D003550:Cystic Fibrosis / Q000503:physiopathology*; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D064426:Gasotransmitters / Q000378:metabolism; D006801:Humans; D008297:Male; D011653:Pulmonary Diffusing Capacity / Q000502:physiology*; D015203:Reproducibility of Results; D013147:Spirometry
chemical_list: D064426:Gasotransmitters; D002248:Carbon Monoxide
keywords: children; cystic fibrosis; diffusion capacity; elite swimmers; peak oxygen consumption