Document Detail


A mathematical model of human respiration at altitude.
MedLine Citation:
PMID:  17674206     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We developed a mathematical model of human respiration in the awake state that can be used to predict changes in ventilation, blood gases, and other critical variables during conditions of hypocapnia, hypercapnia and these conditions combined with hypoxia. Hence, the model is capable of describing ventilation changes due to the hypocapnic-hypoxia of high altitude. The basic model is that of Grodins et al. [Grodins, F. S., J. Buell, and A. J. Bart. J. Appl. Physiol. 22:260-276, 1967]. We updated the descriptions of (1) the effects of blood gases on cardiac output and cerebral blood flow, (2) acid-base balance in blood and tissues, (3) O2 and CO2 binding to hemoglobin and most importantly, (4) the respiratory-chemostat controller. The controller consists of central and peripheral sections. The central chemoceptor-induced ventilation response is simply a linear function of brain P(CO2) above a threshold value. The peripheral response has both a linear term similar to that for the central chemoceptors, but dependent upon carotid body P(CO2) and with a different threshold and a complex, nonlinear term that includes multiplication of separate terms involving carotid body P(O2) and P(CO2). Together, these terms produce 'dogleg'-shaped curves of ventilation plotted against P(CO2) which form a fan-like family for different values of P(CO2). With this chemical controller, our model closely describes a wide range of experimental data under conditions of solely changes in P(CO2) and for short-term hypoxia coupled with P(CO2) changes. This model can be used to accurately describe changes in ventilation and respiratory gases during ascent and during short-term residence at altitude. Hence, it has great applicability to studying O2-delivery systems in aircraft.
Authors:
Matthew Bernard Wolf; Robert P Garner
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Publication Detail:
Type:  Journal Article     Date:  2007-08-03
Journal Detail:
Title:  Annals of biomedical engineering     Volume:  35     ISSN:  0090-6964     ISO Abbreviation:  Ann Biomed Eng     Publication Date:  2007 Nov 
Date Detail:
Created Date:  2007-10-23     Completed Date:  2008-01-08     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0361512     Medline TA:  Ann Biomed Eng     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2003-22     Citation Subset:  IM    
Affiliation:
Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, 6439 Garners Ferry Road, Columbia, SC 29209, USA. wolf@med.sc.edu
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MeSH Terms
Descriptor/Qualifier:
Altitude*
Anoxia / physiopathology
Humans
Hypercapnia / physiopathology
Hypocapnia / physiopathology
Models, Statistical*
Respiration*
Tidal Volume

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


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