Document Detail

The effects of chronic airflow limitation, increased dead space, and the pattern of ventilation on gas exchange during maximal exercise in advanced cystic fibrosis.
MedLine Citation:
PMID:  3144220     Owner:  NLM     Status:  MEDLINE    
Although exertional hypercapnea has been observed in patients with advanced cystic fibrosis (CF), the causes have not been fully elucidated. In 14 patients aged 15 to 35 yr of age with advanced CF, the effects of chronic airflow limitation (CAL), increased physiologic dead space (VD), and the timing components of ventilation (VE) on gas exchange during maximal exercise were assessed. The patients were divided into those who retained CO2 during exercise, the CO2R group, and those who did not, the CO2NR group. CO2 retention was defined as a rise in end-tidal CO2 tension of 5 mm Hg or more or to a value greater than 50 mm Hg during a progressive exercise test on a cycle ergometer. CO2 retention occurred in half the subjects, usually by the halfway mark of the test, and did not rise progressively as exercise continued. It was associated with a low VE caused by a low tidal volume (VT) that was the result of a short inspiratory time to total respiratory time ratio (0.33 +/- 0.03 versus 0.38 +/- 0.04, p less than 0.02), whereas there was no difference in mean inspiratory flow or respiratory rate. Although the CO2R group had the worst CAL, with a FEV1 of 28 +/- 7 versus 41 +/- 12% predicted (p less than 0.5) and a FVC of 42 +/- 12 versus 61 +/- 9% predicted (p less than 0.01), the VT at maximal work expressed as a percentage of FVC was lower (45 +/- 13 versus 60 +/- 11, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
A L Coates; G Canny; R Zinman; R Grisdale; K Desmond; D Roumeliotis; H Levison
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The American review of respiratory disease     Volume:  138     ISSN:  0003-0805     ISO Abbreviation:  Am. Rev. Respir. Dis.     Publication Date:  1988 Dec 
Date Detail:
Created Date:  1989-01-24     Completed Date:  1989-01-24     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0370523     Medline TA:  Am Rev Respir Dis     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1524-31     Citation Subset:  AIM; IM    
Department of Pediatric, McGill University, Montreal Children's Hospital Research Institute, Toronto, Ontario, Canada.
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MeSH Terms
Carbon Dioxide / physiology
Cystic Fibrosis / complications,  physiopathology*
Exercise Test
Lung Diseases, Obstructive / etiology,  physiopathology*
Pulmonary Gas Exchange
Pulmonary Ventilation
Respiratory Dead Space
Respiratory Function Tests
Reg. No./Substance:
124-38-9/Carbon Dioxide

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