Document Detail


Is static hyperinflation a limiting factor during exercise in adolescents with cystic fibrosis?
MedLine Citation:
PMID:  20812244     Owner:  NLM     Status:  In-Data-Review    
Abstract/OtherAbstract:
Increased work of breathing is considered to be a limiting factor in patients with cystic fibrosis (CF) performing aerobic exercise. We hypothesized that adolescents with CF and with static hyperinflation are more prone to a ventilatorily limited exercise capacity than non-static hyperinflated adolescents with CF. Exercise data of 119 adolescents with CF [range 12-18 years], stratified for static hyperinflation, defined as ratio of residual volume to total lung capacity (RV/TLC) > 30%, were obtained during a progressive bicycle ergometer test with gas analysis and analyzed for ventilatory limitation. Static hyperinflation showed a significant, though weak association (Φ 0.38; P < 0.001) with a ventilatorily limited exercise capacity (breathing reserve index at maximal effort >0.70; FEV(1)  < 80% predicted and reduced exercise capacity, defined as VO(2peak)  < 85% predicted). Analysis of association for increasing degrees of hyperinflation showed an increase to Φ 0.49 (P < 0.001) for RV/TLC > 50%. In adolescents with static hyperinflation, peak work rate (W(peak) ; 3.1 ± 0.7 W/kg (75.1 ± 17.3% of predicted), peak oxygen uptake (VO(2peak) /kg (ml/min/kg); 39.2 ± 9.2 ml/min/kg (91.0 ± 20.3% of predicted), peak heart rate (HR(peak) ; 176 ± 19 beats/min) were significantly (P < 0.05) decreased when compared with non-static hyperinflated adolescents (W(peak) 3.5 ± 0.5 W/kg (81.4 ± 10.0% of predicted)); VO(2peak) /kg (ml/min/kg); 43.1 ± 7.5 ml/min/kg (98.0 ± 15.1% of predicted); and HR(peak) 185 ± 14 beats/min). Additionally, no difference was found in the degree of association of FEV(1) (%) and RV/TLC (%) with VO(2peak) /kg(pred) and W(peak) /kg(Pred) , but we found the RV/TLC (%) to be a slightly stronger predictor of VO(2peak) /kg(pred) and W(peak) /kg(Pred) than FEV(1) (%). These results indicate that the presence of static hyperinflation in adolescents with CF by itself does not strongly influence ventilatory constraints during exercise and that static hyperinflation is only a slightly stronger predictor of W(peak) /kg(Pred) and VO(2peak) /kg(Pred) than airflow obstruction (FEV(1) (%)). Pediatr. Pulmonol. 2011; 46:119-124. © 2011 Wiley-Liss, Inc.
Authors:
M S Werkman; H J Hulzebos; H G M Arets; J van der Net; P J M Helders; T Takken
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Publication Detail:
Type:  Journal Article     Date:  2010-09-01
Journal Detail:
Title:  Pediatric pulmonology     Volume:  46     ISSN:  1099-0496     ISO Abbreviation:  Pediatr. Pulmonol.     Publication Date:  2011 Feb 
Date Detail:
Created Date:  2011-01-24     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8510590     Medline TA:  Pediatr Pulmonol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  119-24     Citation Subset:  IM    
Copyright Information:
Copyright © 2011 Wiley-Liss, Inc.
Affiliation:
Child Development & Exercise Center, Cystic Fibrosis Center, University Medical Center Utrecht, Utrecht, the Netherlands.
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