Abstract
A microcomputer program written in BASIC for the IBM-PC and compatibles has been developed to analyze the effects of many parameters on the gas exchange and transport phenomena in the lungs and the tissues. The program is designed for use by medical students and residents concerned with gas exchange (anesthesiology, pulmonary diseases, critical care, etc.) to study the steady state effects on blood and tissue oxygen and carbon dioxide levels. The present program consists of two main subroutines: Pulmonary Gas Exchange and Tissue Gas Exchange. Steady state gas exchange at the lungs can be studied using either a three-compartment model or V/Q relationships. The V/Q subroutine uses single or multiple populations of V/Q distributions to determine gas exchange using a log-normal distribution of V/Q ratios. Other variables can be adjusted which determine the arterial and mixed-venous blood gases. These values are then fed into the second part of the program to analyze factors which determine tissue O2 tension. The Tissue Oxygen Tension subroutine is also subdivided into a modified Krogh-Erlang model, which provides a three-dimensional plot of theoretical capillary and tissue O2 tensions, and a Piiper model which includes the effect of diffusion shunt on O2 tensions and treats the tissue as a well-stirred compartment. Minimal and maximal tissue O2 tensions are calculated using the Piiper model since the intercapillary distance is allowed to vary depending on the O2 delivery by diffusion. Estimates of blood and tissue O2 tensions, diffusion/perfusion coefficients, amount of O2 delivered and the size of the active capillary bed are summarized in a table.
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References
Altman, P.L. and D.S. Dittmer,Respiration and Circulation. Bethesda, MD: FASEB, 1971.
Boyle III, J. Graphic analysis of the Fick equation to evaluate oxygen transport.Respiration 45:353–359, 1984.
Haab, P. A model for the study of diffusion and perfusion limitation.Fed. Proc. 41:2119–22, 1982.
Hill, A.V. The possible effects of the aggegation of the molecules of haemoglobin on its dissociation curves.J. Physiol. (London) 142:iv, 1910.
Kelman, G.R. Digital computer subroutine for the conversion of oxygen tension into saturation.J. Appl. Physiol. 12:1375–1376, 1966.
Kreuzer, F. Oxygen supply to tissues: the Krogh model and its assumptions.Experientia 38:1415–1426, 1984.
Krogh, A. The number and distribution of capillaries in muscle with calculation of the oxygen pressure head necessary for supplying the tissue.J. Physiol. (London) 52:409–415, 1918/19.
Mahutte, C.K., T.M. Michiels, K.T. Hassel and D.M. Trueblood. Evaluation of a single transcutaneous PO2 and PCO2 sensor in adult patients.Critical Care Med. 12:1063–1066, 1984.
Miller, M.J. Tissue oxygenation in clinical medicine: an historical review.Anesth. Analges. 61:527–535, 1982.
Mithoeffer, J.C., F.D. Holford and J.F.H. Keighley. The effect of oxygen administration on mixed venous oxygenation in chronic obstructive pulmonary disease.Chest 66:11–132, 1974.
Nelimarkka, O., L. Halkola and J. Niinikoski. Renal hypoxia and lactate metabolism in hemorrhagic shock in dogs.Critical Care Med. 12:656–660, 1984.
Piiper, J., M. Meyer and P. Scheid. Dual role of diffusion in tissue gas exchange: blood:tissue equilibration and diffusion shunt.Respir. Physiol. 56:131–144, 1984.
Severinghaus, J.B. Blood gas calculator.J. Appl. Physiol. 12:1108–1116, 1966.
Riley, R.L. and A. Cournand. “Ideal” alveolar air and the analysis of ventilation-perfusion ratios in the lungs.J. Appl. Physiol. 1:825–847, 1949.
Riley, R.L. and A. Cournand. Analysis of factors affecting partial pressures of oxygen and carbon dioxide in gas and blood of lungs: Theory.J. Appl. Physiol. 4:102–120, 1951.
Riley, R.L., A. Cournand and K.W. Donald. Analysis of factors affecting partial pressures of oxygen and carbon dioxide in gas and blood of lungs: Methods.J. Appl. Physiol. 4:102–120, 1951.
Spain, J.D.BASIC Microcomputer Models in Biology. Reading, MA: Addison-Wesley, 1982.
Sugimoto, H., N. Ohashi, Y. Sawada, T. Yoshioka and T. Sugimoto. Effects of positive end-expiratory pressure on tissue gas tensions and oxygen transport.Critical Care Med. 12:661–663, 1984.
Tenney, S.M. and T.W. Lamb. Physiological consequences of hyperventilation and hypoventilation. In:Handbook of Physiology. Section 3. Respiration Physiology, Vol. 2., edited by W.O. Fenn and H. Rahn. Washington, D.C.: American Physiological Society, 1965.
Tenney, S.M. and J.C. Mithoeffer. The relationship of mixed venous oxygenation to oxygen transport: with special reference to adaptation to high altitude and pulmonary disease.Am. Rev. Resp. Dis. 125:474–479, 1982.
Vincent, J.L. et al. Serial lactate determinations during circulatory shock.Critical Care Med. 11:449–451, 1983.
Wagner, P.D. and J.W. Evans, Conditions of equivalence for gas exchange in series and parallel models of the lung.Resp. Physiol. 31:117–138, 1977.
Wagner, P.D., H.A. Saltzman and J.B. West. Measurement of continuous distributions of ventilation-perfusion ratios: theory.J. Appl. Physiol. 36:588–599, 1974.
Weibel, E.R.The Oxygen Pathway. Cambridge, MA: Harvard University Press, 1984.
West, J.B. Ventilation-Perfusion Relationships.Am. Rev. Resp. Dis. 116:919–943, 1977.
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Boyle, J. A microcomputer program of pulmonary and tissue gas exchange. Ann Biomed Eng 14, 425–435 (1986). https://doi.org/10.1007/BF02367363
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DOI: https://doi.org/10.1007/BF02367363