Document Detail

Assessment of arterial gas pressures and cardiac output using a breathing lung model.
MedLine Citation:
PMID:  12439079     Owner:  NLM     Status:  MEDLINE    
PURPOSE: The aim of this investigation was to evaluate a breathing lung model to estimate arterial gas partial pressures and cardiac output at rest and during exercise. METHODS: A mathematical model was used to describe variations in gas fractions, alveolar volume, and gas exchange in the pulmonary capillaries during the breathing cycle. Experimental data were obtained from 17 healthy subjects at rest and during exercise at 40, 50, 65, and 75% VO(2max) on a cycle ergometer. VO(2), VCO(2), and P(ET,CO2) were monitored continuously with a MedGraphics CPX/D gas exchange system. Arterial gases were measured in brachial artery blood samples drawn simultaneously with gas exchange. Cardiac output was measured using the CO(2) rebreathing method corrected by the arterial blood sample data. The model parameters including cardiac output, end-expiratory alveolar volume, and mixed-venous gas contents were estimated by fitting modelVCO(2) to experimental values over 50 breaths. RESULTS: The fit of model parameters gave arterial gas partial pressures not significantly different from measured data. Measured P(a,C02) and P(a,O2) were significantly correlated with model outputs (R(2) = 0.991 for P(a,CO2) and R(2) = 0.999 for P(a, CO2); P < 0.0001). The cardiac output values estimated using the breathing lung model were significantly correlated with the values obtained with the corrected CO rebreathing method (R(2) = 0.71; P < 0.0001). There was, however, a significant 2.3 L x min(-1) difference between these two methods. CONCLUSION: Results obtained with the proposed method were in good agreement with measured arterial gas partial pressures. Despite a certain degree of bias, the promising results for cardiac output demonstrate the reliability of this method that should be now evaluated using a gold standard method.
Habib Benallal; Christian Denis; Fabrice Prieur; Thierry Busso
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Publication Detail:
Type:  Clinical Trial; Comparative Study; Journal Article    
Journal Detail:
Title:  Medicine and science in sports and exercise     Volume:  34     ISSN:  0195-9131     ISO Abbreviation:  Med Sci Sports Exerc     Publication Date:  2002 Nov 
Date Detail:
Created Date:  2002-11-19     Completed Date:  2003-03-06     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8005433     Medline TA:  Med Sci Sports Exerc     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1750-6     Citation Subset:  IM; S    
Laboratoire de Physiologie et Physiopathologie de L'Exercice et Handicap--Groupement d'Intérêt Public Exercice, Sport et Santé, Université Jean Monnet, Saint-Etienne, France.
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MeSH Terms
Analysis of Variance
Blood Gas Analysis*
Cardiac Output / physiology*
Exercise / physiology*
Linear Models
Models, Biological*
Prospective Studies
Pulmonary Gas Exchange / physiology*
Pulmonary Ventilation / physiology*
Reference Values
Respiratory Mechanics
Sensitivity and Specificity
Tidal Volume

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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