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Diffusing‐Capacity Heterogeneity

Michael P. Hlastala

10.1002/cphy.cp030412

Source: Supplement 13: Handbook of Physiology, The Respiratory System, Gas Exchange

Originally published: 1987

Published online: January 2011

Full Article on Wiley Online Library



Abstract

The sections in this article are:

1 Gas Equilibration Across Alveolar‐Capillary Membrane
2 Regional Diffusing‐Capacity Heterogeneity
2.1 Theoretical Considerations
2.2 Experimental Evidence for Diffusing‐Capacity Heterogeneity
2.3 Differential Effect of Diffusing‐Capacity Heterogeneity on O2 and CO Transfer
2.4 Exercise
2.5 Pulmonary Capillary Transit Time
2.6 Vertical Distribution of Diffusing Capacity
2.7 Carrier‐Gas Density
2.8 Comparison of Physiological and Morphological Measurements of Diffusing Capacity
3 Interaction of Ventilation‐Perfusion Heterogeneity with Diffusing‐Capacity Heterogeneity
4 Solubility Dependence of Gas Exchange
5 Molecular‐Weight Dependence of Gas Exchange
6 Combined Solubility and Molecular‐Weight Dependence
7 Future Directions
Figure 1. Figure 1.

Factors affecting equilibration of gas in pulmonary capillary of homogeneous lung. βb, Capacitance coefficient of blood; βm, capacitance coefficient of membrane; D, diffusing capacity; dM, differential transport rate of gas; dPb, differential partial pressure of gas in blood; dx, infinitesimal capillary element; Pa, alveolar partial pressure; Pb, partial pressure of gas in blood; Pc, partial pressure of gas in capillary; , partial pressure of mixed venous blood; , perfusion; , alveolar ventilation; O, X, and X0, points along pulmonary capillary.

Adapted from Piiper and Scheid 65
Figure 2. Figure 2.

Equilibration profiles for blood transiting pulmonary capillary for various values of diffusive conductance‐to‐perfusive conductance ratio. (). Partial pressure of gas is plotted as function of relative distance along pulmonary capillary. High values of show perfusion limitation; low values show diffusion limitation. PA, alveolar partial pressure; Pb, partial pressure of gas in blood; PC, partial pressure of gas in capillary; , partial pressure of mixed venous blood; O, X, and X0, points along pulmonary capillary.

Adapted from Piiper and Scheid 64
Figure 3. Figure 3.

Apparent diffusing capacity (“D”) normalized by true diffusing capacity (D) for O2 (A) and CO (B) plotted against relative heterogeneity (σ). •, “D” calculated from average alveolar partial pressures (Ā); ○, “D” calculated from ideal alveolar partial pressures (Aid); ‐ ‐ ‐ ‐ ‐, D distributed in proportion to ; ‐ ‐ ‐ ‐, D distributed according to .

Adapted from Chinet et al. 9
Figure 4. Figure 4.

Curve A, alveolar partial pressure vs. time (t) during a single‐breath diffusing‐capacity measurement (D) as function of breath‐hold time with unequal distribution of diffusing capacity‐to‐alveolar volume ratio (D/VA). Lines 1 and 2, CO profile for compartments 1 and 2. Curve B, homogeneous lung with same overall D. Measured D is determined from slope of chord between alveolar fraction at a specific time [Fa(t)] and original point FAo. VAT, tidal alveolar ventilation.

From Piiper and Sikand 66
Figure 5. Figure 5.

Average results for relative alveolar ventilation‐to‐alveolar volume ratio (), perfusion‐to‐alveolar volume ratio (), and pulmonary diffusing capacity‐to‐alveolar volume ratio (DL/VA) obtained from lobar bronchi in seated humans. Values are expressed relative to value obtained for whole lung. RUL, right upper lobe; RML, right middle lobe; RLL, right lower lobe; LUD, left upper bronchial division; LIN, lingula; LLL, left lower lobe; *, significant difference at 5% level of confidence compared to value for whole lung.

From Denison et al. 14
Figure 6. Figure 6.

Diffusion limitation model of homogeneous lung with alveolar ventilation () and perfusion (). Alveolar compartment A exchanges gas by convection to outside and by diffusion with compartment A′ through gas‐phase diffusive conductance (D′). Compartment A′ also exchanges gas with blood by diffusion through alveolar‐capillary membrane diffusion conductance (Dm). βb, Effective solubility of blood; βm, solubility of gas in membrane; Pc, partial pressure of gas in the capillary; , partial pressure of mixed venous blood.
Figure 7. Figure 7.

Equivalent values of membrane diffusing capacity (Dm) and gas‐phase diffusive conductance (D′) for equal diffusion limitation plotted on log scale. Lines, hypothetical gases with given blood‐gas partition coefficient (λ). Diagonal line, line of identity.


Figure 1.

Factors affecting equilibration of gas in pulmonary capillary of homogeneous lung. βb, Capacitance coefficient of blood; βm, capacitance coefficient of membrane; D, diffusing capacity; dM, differential transport rate of gas; dPb, differential partial pressure of gas in blood; dx, infinitesimal capillary element; Pa, alveolar partial pressure; Pb, partial pressure of gas in blood; Pc, partial pressure of gas in capillary; , partial pressure of mixed venous blood; , perfusion; , alveolar ventilation; O, X, and X0, points along pulmonary capillary.

Adapted from Piiper and Scheid 65


Figure 2.

Equilibration profiles for blood transiting pulmonary capillary for various values of diffusive conductance‐to‐perfusive conductance ratio. (). Partial pressure of gas is plotted as function of relative distance along pulmonary capillary. High values of show perfusion limitation; low values show diffusion limitation. PA, alveolar partial pressure; Pb, partial pressure of gas in blood; PC, partial pressure of gas in capillary; , partial pressure of mixed venous blood; O, X, and X0, points along pulmonary capillary.

Adapted from Piiper and Scheid 64


Figure 3.

Apparent diffusing capacity (“D”) normalized by true diffusing capacity (D) for O2 (A) and CO (B) plotted against relative heterogeneity (σ). •, “D” calculated from average alveolar partial pressures (Ā); ○, “D” calculated from ideal alveolar partial pressures (Aid); ‐ ‐ ‐ ‐ ‐, D distributed in proportion to ; ‐ ‐ ‐ ‐, D distributed according to .

Adapted from Chinet et al. 9


Figure 4.

Curve A, alveolar partial pressure vs. time (t) during a single‐breath diffusing‐capacity measurement (D) as function of breath‐hold time with unequal distribution of diffusing capacity‐to‐alveolar volume ratio (D/VA). Lines 1 and 2, CO profile for compartments 1 and 2. Curve B, homogeneous lung with same overall D. Measured D is determined from slope of chord between alveolar fraction at a specific time [Fa(t)] and original point FAo. VAT, tidal alveolar ventilation.

From Piiper and Sikand 66


Figure 5.

Average results for relative alveolar ventilation‐to‐alveolar volume ratio (), perfusion‐to‐alveolar volume ratio (), and pulmonary diffusing capacity‐to‐alveolar volume ratio (DL/VA) obtained from lobar bronchi in seated humans. Values are expressed relative to value obtained for whole lung. RUL, right upper lobe; RML, right middle lobe; RLL, right lower lobe; LUD, left upper bronchial division; LIN, lingula; LLL, left lower lobe; *, significant difference at 5% level of confidence compared to value for whole lung.

From Denison et al. 14


Figure 6.

Diffusion limitation model of homogeneous lung with alveolar ventilation () and perfusion (). Alveolar compartment A exchanges gas by convection to outside and by diffusion with compartment A′ through gas‐phase diffusive conductance (D′). Compartment A′ also exchanges gas with blood by diffusion through alveolar‐capillary membrane diffusion conductance (Dm). βb, Effective solubility of blood; βm, solubility of gas in membrane; Pc, partial pressure of gas in the capillary; , partial pressure of mixed venous blood.



Figure 7.

Equivalent values of membrane diffusing capacity (Dm) and gas‐phase diffusive conductance (D′) for equal diffusion limitation plotted on log scale. Lines, hypothetical gases with given blood‐gas partition coefficient (λ). Diagonal line, line of identity.

References
 1. Adaro, F., and L. E. Farhi. Effects of intralobular gas diffusion on alveolar gas exchange (Abstract). Federation Proc. 30: 437, 1971.
 2. Arndt, H., T. K. C. King, and W. A. Briscoe. Diffusing capacities and ventilation perfusion ratios in patients with the clinical syndrome of alveolar capillary block. J. Clin. Invest. 49: 408–422, 1970.
 3. Bidani, A., R. W. Flumerfelt, and E. D. Crandall. Analysis of the effects of pulsatile capillary blood flow and volume on gas exchange. Respir. Physiol. 35: 27–42, 1978.
 4. Briscoe, W. A., and T. K. C. King. The diffusing capacity of the lung in obstructive disease studied with the aid of Bohr integral isopleths. Am. Rev. Respir. Dis. 95: 891–893, 1967.
 5. Burns, B., and R. H. Shepard. Dlo2 in excised lungs perfused with blood containing sodium dithionite (Na2S2O4). J. Appl. Physiol. 46: 100–110, 1979.
 6. Burrows, B., A. H. Niden, P. V. Harper, Jr., and W. R. Barclay. Non‐uniform pulmonary diffusion as demonstrated by the carbon monoxide equilibration technique: mathematical considerations. J. Clin. Invest. 39: 795–801, 1960.
 7. Burrows, Niden, C. Mittman, R. C. Talley, and W. R. Barclay. Non‐uniform pulmonary diffusion as demonstrated by the carbon monoxide equilibration technique: experimental results in man. J. Clin. Invest. 39: 943–951, 1960.
 8. Cassidy, S. S., M. Ramanathan, G. L. Rose, and R. L. Johnson, Jr. Hysteresis in the relation between diffusing capacity of the lung and lung volume. J. Appl. Physiol. 49: 566–570, 1980.
 9. Chinet, A., J. L. Micheli, and P. Haab. Inhomogeneity effects on O2 and CO pulmonary diffusing capacity estimates by steady‐state methods: theory. Respir. Physiol. 13: 1–22, 1971.
 10. Christopherson, S. K., and M. P. Hlastala. Pulmonary gas exchange during altered density gas breathing. J. Appl. Physiol. 52: 221–225, 1982.
 11. Cotton, D. J., and B. L. Graham. Effect of ventilation and diffusion nonuniformity on DlCo (exhaled) in a lung model. J. Appl. Physiol. 48: 648–656, 1980.
 12. Cotton, D. J., C. J. L. Newth, P. M. Portner, and J. A. Nadel. Measurement of single‐breath CO diffusing capacity by continuous rapid CO analysis in man. J. Appl. Physiol. 46: 1149–1156, 1979.
 13. Cross, C. E., H. Gong, Jr., C. J. Kurpershoek, J. R. Gillespie, and R. W. Hyde. Alterations in distribution of blood flow to the lung's diffusion surfaces during exercise. J. Clin. Invest. 52: 414–421, 1973.
 14. Denison, D. M., N. J. H. Davies, M. Meyer, R. J. Pierce, and P. Scheid. Single‐exhalation method for study of lobar and segmental lung function by mass spectrometry in man. Respir. Physiol. 42: 87–99, 1980.
 15. Dollery, C. T., N. A. Dyson, and J. D. Sinclair. Regional variation in uptake of radioactive CO in the normal lung. J. Appl. Physiol. 15: 411–417, 1960.
 16. Farhi, L. E. Elimination of inert gas by the lung. Respir. Physiol. 3: 1–11, 1967.
 17. Farhi, L. E., and T. Yokoyama. Effects of ventilation‐perfusion inequality on elimination of inert gases. Respir. Physiol. 3: 12–20, 1967.
 18. Felton, C., G. L. Rose, S. S. Cassidy, and R. L. Johnson, Jr. Comparison of lung diffusing capacity during rebreathing and during slow exhalation. Respir. Physiol. 43: 13–22, 1981.
 19. Forster, R. E. Exchange of gases between alveolar air and pulmonary capillary blood: pulmonary diffusing capacity. Physiol. Rev. 37: 391–452, 1957.
 20. Forster, R. E., W. S. Fowler, D. V. Bates, and B. Van Lingen. The absorption of carbon monoxide by the lungs during breathholding. J. Clin. Invest. 33: 1135–1145, 1954.
 21. Gehr, P., M. Bachofen, and E. R. Weibel. The normal human lung: ultrastructure and morphometric estimation of diffusion capacity. Respir. Physiol. 32: 121–140, 1978.
 22. Geiser, F., A. Chinet, and P. Haab. Pulmonary O2 diffusing capacity estimates from assumed log‐normal Va/Q distributions. Respir. Physiol. 36: 31–44, 1979.
 23. Gong, H., Jr., C. J. Kurpershoek, D. H. Meyer, and C. E. Cross. Effects of cardiac output on 18O2 lung diffusion in normal resting man. Respir. Physiol. 16: 313–326, 1972.
 24. Gurtner, G. H., and W. S. Fowler. Interrelationships of factors affecting pulmonary diffusing capacity. J. Appl. Physiol. 30: 619–624, 1971.
 25. Hamer, N. A. J. Variations in the components of the diffusing capacity as the lung expands. Clin. Sci. 24: 275–285, 1963.
 26. Hatzfeld, C., F. Wiener, and W. A. Briscoe. Effects of uneven ventilation‐diffusion ratios on pulmonary diffusing capacity in disease. J. Appl. Physiol. 23: 1–10, 1967.
 27. Hayek, H. von. The Human Lung. New York: Hafner, 1960.
 28. Hlastala, M. P. A model of fluctuating alveolar gas exchange during the respiratory cycle. Respir. Physiol. 15: 214–232, 1972.
 29. Hlastala, M. P. Significance of the Bohr and Haldane effects in the pulmonary capillary. Respir. Physiol. 17: 81–92, 1973.
 30. Hlastala, M. P., H. P. McKenna, M. Middaugh, and H. T. Robertson. The role of diffusion‐dependent gas inhomogeneity in gas exchange in the dog. Bull. Eur. Physiopathol. Respir. 18: 373–380, 1982.
 31. Hlastala, M. P., and H. T. Robertson. Inert gas elimination characteristic of the normal and abnormal lung. J. Appl. Physiol. 44: 258–266, 1978.
 32. Hlastala, M. P., P. Scheid, and J. Piiper. Interpretation of inert gas retention and excretion in the presence of stratified inhomogeneity. Respir. Physiol. 46: 247–259, 1982.
 33. Hughes, J. M. B., E. H. Clark, P. W. Wean, A. P. Greening, H. A. Jones, D. J. Lipscomb, H. C. Middleton, J. N. Pande, and C. G. Rhodes. Overall and regional Dlco studies in normal and abnormal lungs. Prog. Respir. Res. 16: 142–146, 1981.
 34. Hyde, R. W., M. G. Marin, R. I. Rynes, G. Karreman, and R. E. Forster. Measurement of uneven distribution of pulmonary blood flow to CO diffusing capacity. J. Appl. Physiol. 31: 605–612, 1971.
 35. Hyde, R. W., R. Rynes, G. G. Power, and J. Nairn. Determination of distribution of diffusing capacity in relation to blood flow in the human lung. J. Clin. Invest. 46: 463–474, 1967.
 36. Johnson, R. L., Jr., and J. M. Miller. Distribution of ventilation, blood flow, and gas transfer coefficients in the lung. J. Appl. Physiol. 25: 1–15, 1968.
 37. Kawashiro, T., A. C. Carles, S. F. Perry, and J. Piiper. Diffusivity of various inert gases in rat skeletal muscle. Pfluegers Arch. 359: 219–230, 1975.
 38. King, T. K. C., and W. A. Briscoe. Bohr integral isopleths in the study of blood gas exchange in the lung. J. Appl. Physiol. 22: 659–674, 1967.
 39. King, T. K. C., and W. A. Briscoe. Blood gas exchange in emphysema: an example illustrating method of calculation. J. Appl. Physiol. 23: 672–682, 1967.
 40. King, T. K. C., and W. A. Briscoe. The distribution of ventilation, perfusion, lung volume and transfer factor (diffusing capacity) in patients with obstructive lung disease. Clin. Sci. Land. 35: 153–170, 1968.
 41. Knopp, T. J., and J. B. Bassingthwaighte. Effect of flow on transpulmonary circulatory transport functions. J. Appl. Physiol. 27: 36–43, 1969.
 42. Kotter, D., A. Huch, H. Stotz, and J. Piiper. Single breath CO diffusing capacity in anesthetized dogs with increased oxygen consumption. Respir. Physiol. 6: 202–208, 1969.
 43. Kvale, P. A., J. Davis, and R. C. Schroter. Effect of gas density and ventilatory pattern on steady‐state CO uptake by the lung. Respir. Physiol. 24: 385–398, 1975.
 44. Lewis, B. M., E. J. Hayford‐Welsing, A. Furusho, and L. C. Reed, Jr. Effect of uneven ventilation on pulmonary diffusing capacity. J. Appl. Physiol. 16: 679–683, 1961.
 45. Lewis, S. M., D. Z. Rubin, and C. Mittman. Distribution of ventilation and diffusing capacity in the normal and diseased lung. J. Appl. Physiol. 51: 1463–1470, 1981.
 46. Lilienthal, J. L., Jr., R. L. Riley, D. D. Proemmel, and R. E. Franke. An experimental analysis in man of the oxygen pressure gradient from alveolar air to arterial blood during rest and exercise at sea level and at altitude. Am. J. Physiol. 147: 199–216, 1946.
 47. Lodato, R. F. Quantification of Oxygen Diffusing Capacity in the Lung with Mismatch of Ventilation and Perfusion by Comparison of the Exchange of Oxygen and Inert Gases. Baltimore, MD: Johns Hopkins Univ. Press, 1978. PhD thesis.
 48. Luijendijk, S. C. M., A. Zwart, W. R. de Vries, and W. M. Salet. The sloping alveolar plateau at synchronous ventilation. Pfluegers Arch. 384: 267–277, 1980.
 49. Magnussen, H. Single breath diffusing capacity for carbon monoxide in bronchial asthma and emphysema. Prog. Respir. Res. 16: 147–151, 1981.
 50. Menkes, H. A., K. Sera, R. M. Rogers, R. W. Hyde, R. E. Forster II, and A. B. Du Bois. Pulsatile uptake of CO in the human lung. J. Clin. Invest. 49: 335–345, 1970.
 51. Meyer, M., P. Scheid, C. Riepl, H.‐J. Wagner, and J. Piiper. Pulmonary diffusing capacities for O2 and CO measured by a rebreathing technique. J. Appl. Physiol. 51: 1643–1650, 1981.
 52. Michaelson, E. D., M. A. Sackner, and R. L. Johnson, Jr. Vertical distributions of pulmonary diffusing capacity and capillary btood flow in man. J. Clin. Invest. 52: 359–369, 1973.
 53. Miller, J. M., and R. L. Johnson, Jr. Effect of lung inflation on pulmonary diffusing capacity at rest and exercise. J. Clin. Invest. 45: 493–500, 1966.
 54. Mittman, C. Nonuniform pulmonary diffusing capacity measured by sequential CO uptake and washout. J. Appl. Physiol. 23: 131–138, 1967.
 55. Nairn, J. R., G. G. Power, R. W. Hyde, R. E. Forster, C. J. Lambertsen, and J. Dickson. Diffusing capacity and pulmonary capillary blood flow at hyperbaric pressures. J. Clin. Invest. 44: 1591–1599, 1965.
 56. Neufeld, G. R., J. J. Williams, P. L. Klineberg, and B. E. Marshall. Inert gas a‐A differences: a direct reflection of V/Q. distribution. J. Appl. Physiol. 44: 277–283, 1978.
 57. Newth, C. J. L., D. J. Cotton, and J. A. Nadel. Pulmonary diffusing capacity measured at multiple intervals during a single exhalation in man. J. Appl. Physiol. 43: 617–625, 1977.
 58. Paiva, M., and L. A. Engel. Pulmonary interdependence of gas transport. J. Appl. Physiol. 47: 296–305, 1979.
 59. Piiper, J. Unequal distribution of pulmonary diffusing capacity and the alveolar‐arterial Po2 differences: theory. J. Appl. Physiol. 16: 493–498, 1961.
 60. Piiper, J. Variations of ventilation and diffusing capacity to perfusion determining the alveolar‐arterial O2 difference: theory. J. Appl. Physiol. 16: 507–516, 1961.
 61. Piiper, J. Apparent increase of the O2 diffusing capacity with increased O2 uptake in inhomogeneous lungs: theory. Respir. Physiol. 6: 209–218, 1969.
 62. Piiper J., P. Dejours, P. Haab, and H. Rahn. Concepts and basic quantities in gas exchange physiology. Respir. Physiol. 13: 292–304, 1971.
 63. Piiper, J., P. Haab, and H. Rahn. Unequal distribution of pulmonary diffusing capacity in the anesthetized dog. J. Appl. Physiol. 16: 499–506, 1960.
 64. Piiper, J., A. Huch, D. Kotter, and R. Herbst. Pulmonary diffusing capacity at basal and increased O2 uptake levels in anesthetized dogs. Respir. Physiol. 6: 219–232, 1969.
 65. Piiper, J., and P. Scheid. Blood‐gas equilibration in lungs. In: Pulmonary Gas Exchange. Ventilation, Blood Flow, and Diffusion, edited by J. B. West. New York: Academic, 1980, vol. 1, p. 131–171.
 66. Piiper, J., and P. Scheid. Model for capillary‐alveolar equilibration with special reference to O2 uptake in hypoxia. Respir. Physiol. 46: 193–208, 1981.
 67. Piiper, J., and R. S. Sikand. Determination of Dco by the single breath method in inhomogeneous lungs: theory. Respir. Physiol. 1: 75–87, 1966.
 68. Rauwerda, P. E. Unequal Ventilation of Different Parts of the Lung and the Determination of Cardiac Output. Gröningen, The Netherlands: State Univ. of Gröningen, 1946. PhD thesis.
 69. Read, J. Stratification of ventilation and blood flow in the normal lung. J. Appl. Physiol. 21: 1521–1531, 1966.
 70. Rose, G. L., S. S. Cassidy, and R. L. Johnson, Jr. Diffusing capacity at different lung volumes during breath holding and rebreathing. J. Appl. Physiol. 47: 32–37, 1979.
 71. Roughton, F. J. W., and R. E. Forster. Relative importance of diffusion and chemical reaction rates in determining rate of exchange of gases in the human lung, with special reference to true diffusing capacity of pulmonary membrane and volume of blood in the lung capillaries. J. Appl. Physiol. 11: 290–302, 1957.
 72. Savoy, J. M., M. C. Michoud, M. Robert, J. Geiser, P. Haab, and J. Piiper. Comparison of steady state pulmonary diffusing capacity estimates for O2 and CO in dogs. Respir. Physiol. 42: 43–59, 1980.
 73. Scheid, P., F. Adaro, J. Teichmann, and J. Piiper. Rebreathing and steady state pulmonary Do2 in the dog and in inhomogeneous lung models. Respir. Physiol. 18: 258–272, 1973.
 74. Scheid, P., M. P. Hlastala, and J. Piiper. Inert gas elimination from lungs with stratified inhomogeneity: theory. Respir. Physiol. 44: 299–309, 1981.
 75. Scheid, P., and J. Piiper. Intrapulmonary gas mixing and stratification. In: Pulmonary Gas Exchange. Ventilation, Blood Flow, and Diffusion, edited by J. B. West. New York: Academic, 1980, vol. 1, p. 88–130.
 76. Schmidt, W., C. Thews, and K. H. Schnabel. Results of distribution analysis of ventilation, perfusion and O2 diffusing capacity in the human lung. Respiration 29: 1–16, 1982.
 77. Siegwart, B., P. Gehr, J. Gil, and E. R. Weibel. Morphometric estimation of pulmonary diffusion capacity. IV. The normal dog lung. Respir. Physiol. 13: 141–159, 1971.
 78. Sikand, R. S., and J. Piiper. Pulmonary diffusing capacity for CO in dogs by the single breath method. Respir. Physiol. 1: 172–192, 1966.
 79. Spicer, W. S., Jr., R. L. Johnson, Jr., and R. E. Forster II. Diffusing capacity and blood flow in different regions of the lung. J. Appl. Physiol. 17: 587–595, 1962.
 80. Staub, N. C., and E. L. Schultz. Pulmonary capillary length in dog, cat and rabbit. Respir. Physiol. 5: 371–378, 1968.
 81. Thews, G., W. Schmidt, and K. H. Schnabel. Analysis of distribution inhomogeneities of ventilation, perfusion, and O2 diffusing capacity in the human lung. Respiration 28: 197–215, 1971.
 82. Thews, G., and H. R. Vogel. Die Verteilungsanalyse von Ventilation, Perfusion und O2‐Diffusionskapazität in der Lunge durch Konzentrationswechsel dreier Inspirationsgase. I. Theorie. Pfluegers Arch. 303: 195–205, 1968.
 83. Truog, W. E., M. P. Hlastala, T. A. Standaert, H. P. McKenna, and W. A. Hodson. Oxygen‐induced alteration of ventilation‐perfusion relationships in rats. J. Appl. Physiol. 47: 1112–1117, 1979.
 84. Tsunoda, S., A. C. Young, and C. J. Martin. Emptying pattern of lung compartments in normal man. J. Appl. Physiol. 32: 644–649, 1972.
 85. Visser, B. F., and A. H. J. Maas. Pulmonary diffusion of oxygen. Phys. Med. Biol. 3: 264–272, 1959.
 86. Vogel, H. R., and G. Thews. Die Verteilungsanalyse von Ventilation, Perfusion und O2‐Diffusionkapazität in der Lunge durch Konzentrationswechsel dreier Inspirationsgase. II. Durchführung des Verfahrens. Pfluegers Arch. 303: 206–217, 1968.
 87. Vogel, H. R., G. Thews, V. Schultz, and H. J. V. Mengden. Die Verteilungsanalyse von Ventilation, Perfusion und O2‐Diffusionskapazität in der Lunge durch Konzentrationswechsel dreier Inspirationsgase. III. Untersuchung von Jugendlichen, älteren Personen und Schwangeren. Pfluegers Arch. 303: 218–229, 1968.
 88. Wagner, P. D. Diffusion and chemical reaction in pulmonary gas exchange. Physiol. Rev. 57: 257–312, 1977.
 89. Wagner, P., J. McRae, and J. Read. Stratified distribution of blood flow in secondary lobule of the rat lung. J. Appl. Physiol. 22: 1115–1123, 1967.
 90. 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.
 91. Wagner, P. D., and J. B. West. Ventilation‐perfusion relationships. In: Pulmonary Gas Exchange. Ventilation, Blood Flow, and Diffusion, edited by J. B. West. New York: Academic, 1980, vol. 1, p. 219–262.
 92. Wagner, W. W., Jr., L. P. Latham, M. N. Gillespie, J. P. Guenther, and R. L. Capen. Direct measurement of pulmonary capillary transit times. Science Wash. DC 218: 379–381, 1982.
 93. Warrell, D. A., J. W. Evans, R. O. Clarke, G. P. Kingaby, and J. B. West. Pattern of filling in the pulmonary capillary bed. J. Appl. Physiol. 32: 346–356, 1972.
 94. Weibel, E. R., P. Untersee, J. Gil, and M. Zulauf. Morphometric estimation of pulmonary diffusion capacity. IV. Effect of varying positive pressure inflation of air spaces. Respir. Physiol. 18: 285–308, 1973.
 95. West, J. B. Regional differences in gas exchange in the lung of erect man. J. Appl. Physiol. 17: 893–898, 1962.
 96. West, J. B., R. A. B. Holland, C. T. Dollery, and C. M. E. Matthews. Interpretation of radioactive gas clearance rates in the lung. J. Appl. Physiol. 17: 14–20, 1962.
 97. West, J. B., P. D. Wagner, and C. M. W. Derks. Gas exchange in distributions of VA/Q ratios: partial pressure‐solubility diagram. J. Appl. Physiol. 37: 533–540, 1974.
 98. Wood, L. D. H., A. C. Bryan, S. K. Bau, T. R. Weng, and H. Levison. Effect of increased gas density on pulmonary gas exchange in man. J. Appl. Physiol. 41: 206–210, 1976.
 99. Yokoyama, T., and L. E. Farhl. Study of ventilation‐perfusion ratio distribution in the anesthetized dog by multiple inert gas washout. Respir. Physiol. 3: 166–176, 1967.

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Article Title: Diffusing‐Capacity Heterogeneity
 

How to Cite

Michael P. Hlastala. Diffusing‐Capacity Heterogeneity. Compr Physiol 2011, Supplement 13: Handbook of Physiology, The Respiratory System, Gas Exchange: 217-232. First published in print 1987. doi: 10.1002/cphy.cp030412