|
|
||||||||
Journal of Applied Physiology, Vol 53, Issue 2 413-418, Copyright © 1982 by American Physiological Society
ARTICLES |
A. Bidani and E. D. Crandall
A mathematical model of the chemical and transport events in blood during and after gas exchange has been used to examine the rates of CO2 excretion (Vco2) and O2 uptake (Vo2) in the lung at different levels of hematocrit (Hct), assuming fixed mixed venous blood O2 and CO2 contents and alveolar gases and constant cardiac output. The results show that a reduction in Hct from 45 to 30% leads to approximately 25% reduction in Vco2 compared with approximately 30% reduction in Vo2. Reduction of Hct from 45 to 15% results in approximately 50% reduction in Vco2 and approximately 63% reduction in Vo2. An increase in Hct from 45 to 60% results in approximately 25% increase in Vco2, accompanied by approximately 30% increase in Vo2. These fractional changes in gas exchange are only slightly affected by the extent of catalysis of the plasma CO2-H2CO3 hydration-dehydration reactions in the pulmonary vasculature. The reduction in Vco2 with reductions in Hct are due to 1) decrease in the total quantity of Bohr protons released during diminution of Vo2, 2) decrease in the size of the high buffer capacity intraerythrocytic pool, and 3) decrease in the total surface area available for HCO-3/Cl- exchange across the red cell membrane. We conclude that hitherto unrecognized changes in Vco2 (in addition to the well-known changes in Vo2) may occur as a consequence of alterations in Hct.
This article has been cited by other articles:
![]() |
K. M. Gilmour and S. F. Perry Branchial membrane-associated carbonic anhydrase activity maintains CO2 excretion in severely anemic dogfish Am J Physiol Regulatory Integrative Comp Physiol, June 1, 2004; 286(6): R1138 - R1148. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. Stabenau and T. Heming CO2 excretion and postcapillary pH equilibration in blood-perfused turtle lungs J. Exp. Biol., January 4, 1999; 202(8): 965 - 975. [Abstract] [PDF] |
||||
![]() |
V. Cardenas Jr., T. A. Heming, and A. Bidani Kinetics of CO2 excretion and intravascular pH disequilibria during carbonic anhydrase inhibition J Appl Physiol, February 1, 1998; 84(2): 683 - 694. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Deem, M. K. Alberts, M. J. Bishop, A. Bidani, and E. R. Swenson CO2 transport in normovolemic anemia: complete compensation and stability of blood CO2 tensions J Appl Physiol, July 1, 1997; 83(1): 240 - 246. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |