Gas exchange modelling: no more gills, please

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Gas exchange modelling: no more gills, please C.E.W. Hahn, A.D. Farmery British Journal of Anaesthesia Volume 91, Issue 1, Pages 2-15 (July 2003) DOI: 10.1093/bja/aeg142 Copyright © 2003 British Journal of Anaesthesia Terms and Conditions

Fig 1 A schematic diagram of the ‘forwards’ process in biomathematical modelling. British Journal of Anaesthesia 2003 91, 2-15DOI: (10.1093/bja/aeg142) Copyright © 2003 British Journal of Anaesthesia Terms and Conditions

Fig 2 A schematic diagram of the ‘backwards’ or ‘inverse’ process in biomathematical modelling. British Journal of Anaesthesia 2003 91, 2-15DOI: (10.1093/bja/aeg142) Copyright © 2003 British Journal of Anaesthesia Terms and Conditions

Fig 3 Fig 3 Fish gills are complex structures with filaments mounted in paired rows on the gill arches. Gas exchange occurs at the surface of numerous thin lamellae mounted on the filaments. The flow of water between the lamellae is in the opposite direction to blood flow. This counter-current exchanger allows Po2 in arterial blood to rapidly approach that in the inspired water flowing over the lamellae. Reprinted by permission of the publisher from Weibel ER. The Pathway for Oxygen: Structure and Function in the Mammalian Respiratory System. Cambridge, Mass: Harvard University Press, 1984; 17. Copyright ©1984 by the President and Fellows of Harvard College. British Journal of Anaesthesia 2003 91, 2-15DOI: (10.1093/bja/aeg142) Copyright © 2003 British Journal of Anaesthesia Terms and Conditions

Fig 4 A schematic diagram for the conventional continuous gas flow–continuous blood flow model of inert gas exchange in a single-compartment lung. The definitions of symbols are given in the text, and all inputs and outputs are assumed to be in the ‘steady state’. British Journal of Anaesthesia 2003 91, 2-15DOI: (10.1093/bja/aeg142) Copyright © 2003 British Journal of Anaesthesia Terms and Conditions

Fig 5 A schematic diagram for the tidal-ventilation balloon-on-a-straw model of gas exchange in a single-compartment lung, showing the compartment expanding from end-expiratory volume to end-inspiratory volume. Here, all input and output signals are time varying, and the body compartment ‘consumption’ of the gas is ψ(t). The definitions of all other symbols are given in the text. British Journal of Anaesthesia 2003 91, 2-15DOI: (10.1093/bja/aeg142) Copyright © 2003 British Journal of Anaesthesia Terms and Conditions