Theoretical Analysis of Gas Exchange in a Lung Model


A mathematical model, derived from physiological data, is presented to represent gas exchange in the lung during steady state and, for the first time, unsteady state conditions, The model is used to simulate functional defects that can occur in the diseased lung. From a review of available literature four types of defect are recognised, namely, regional inequalities of ventilation, regional inequalities of blood flow, series inequalities and direct pulmonary blood shunts. The effects of changing minute volume, cardiac output and inspired oxygen concentration upon overall gas exchange are studied for each defect when oxygen uptake and carbon dioxide output are held constant at normal values in the steady state. The unsteady state condition is examined during the uptake and elimination of four hypothetical inert gases having differing blood solubilities, The model is used to assess how well certain pulmonary function tests discriminate between the various defects considered, and from information gained a new protocol for defining lung function is proposed. Utilising a more elaborate version of the model, the influence of nitrous oxide induction and excretion upon overall gas exchange is evaluated, The effect of blood recirculation time, minute volume, cardiac output, lung volume and inspired N,0 concentration upon arterial PO2 and PCO2. are examined during the unsteady state. The change in FRC occasioned when inspired and expired volumes are kept constant, are discussed as an alternative to the general case in which FRC is held constant and expired volume varied, A comparison between the model prediction of expired gas tensions with values obtained from three normal subjects during N,0 induction is also included,

Divisions: College of Engineering & Physical Sciences
Additional Information: Copyright © Scrimshire, 1973. D.A. Scrimshire asserts their moral right to be identified as the author of this thesis. This copy of the thesis has been supplied on condition that anyone who consults it is understood to recognise that its copyright rests with its author and that no quotation from the thesis and no information derived from it may be published without appropriate permission or acknowledgement. If you have discovered material in Aston Publications Explorer which is unlawful e.g. breaches copyright, (either yours or that of a third party) or any other law, including but not limited to those relating to patent, trademark, confidentiality, data protection, obscenity, defamation, libel, then please read our Takedown Policy and contact the service immediately.
Institution: Aston University
Uncontrolled Keywords: gas exchange,lung model
Last Modified: 28 Jun 2024 07:06
Date Deposited: 07 Feb 2011 10:14
Completed Date: 1973
Authors: Scrimshire, David A.

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