AJP - Regulatory, Integrative and Comparative Physiology, Vol 264, Issue 2 396-R401, Copyright © 1993 by American Physiological Society

ARTICLES

Hemodynamic changes induced by low blood oxygen affinity in dogs

J. F. Liard and M. P. Kunert
Department of Physiology, Medical College of Wisconsin, Milwaukee 53226.

Increased tissue oxygen delivery may play a role in the increased vascular resistance that develops in volume-expanded hypertension. This hypothesis was tested by decreasing the affinity of hemoglobin for oxygen in dogs to increase unloading of oxygen to the tissues. Six chronically instrumented dogs were studied before and for 7 days after partial exchange transfusion with red blood cells modified by incorporation of inositol hexaphosphate, which, 1 h after exchange, increased the PO2 value at which hemoglobin is half-saturated with oxygen (P50) to 38.8 +/- 2.1 mmHg from a control value of 31 +/- 1.5 mmHg. Cardiac output (electromagnetic flowmeter) fell to 92.5 +/- 7.4 ml.kg-1.min-1 after 2-4 h from control values between 120.2 +/- 5.7 and 125.8 +/- 4.6 ml.kg-1.min-1. One day later, cardiac output was still significantly decreased to 104.0 +/- 5.9 ml.kg-1.min-1. As P50 returned to control over the next few days, so did cardiac output. Two to four hours after exchange, total peripheral resistance was increased to 1,144 +/- 73 mmHg.l-1.kg.min from control values between 762 +/- 26 and 790 +/- 32 mmHg.l-1.kg.min. It was still increased to 993 +/- 51 mmHg.l-1.kg.min after 1 day. Oxygen consumption did not change significantly. Cardiac output and peripheral resistance changes were significantly different from those measured in a control group of six dogs receiving exchange transfusion with sham-shifted red blood cells without significant P50 changes. These results suggest that an increase in tissue oxygen delivery can raise total peripheral resistance in dogs in the absence of primary changes in fluid volumes, blood flow, or blood pressure.

This article has been cited by other articles:

				K. S. Kilgore, C. F. Shwartz, M. A. Gallagher, R. P. Steffen, R. S. Mosca, and S. F. Bolling RSR13, a Synthetic Allosteric Modifier of Hemoglobin, Improves Myocardial Recovery Following Hypothermic Cardiopulmonary Bypass Circulation, November 9, 1999; 100 (2009): II-351 - II-356. [Abstract] [Full Text] [PDF]

				H. Sakai, A. G. Tsai, R. J. Rohlfs, H. Hara, S. Takeoka, E. Tsuchida, and M. Intaglietta Microvascular responses to hemodilution with Hb vesicles as red blood cell substitutes: influence of O2 affinity Am J Physiol Heart Circ Physiol, February 1, 1999; 276(2): H553 - H562. [Abstract] [Full Text] [PDF]

				G Teyssier, J C Fouron, S E Sonesson, P Bonnin, and A Skoll Circulatory changes induced by isovolumic increase in red cell mass in fetal lambs Arch. Dis. Child. Fetal Neonatal Ed., November 1, 1998; 79(3): 180F - 184. [Abstract] [Full Text]

				B. Grassi, L. B. Gladden, C. M. Stary, P. D. Wagner, and M. C. Hogan Peripheral O2 diffusion does not affect VO2 on-kinetics in isolated in situ canine muscle J Appl Physiol, October 1, 1998; 85(4): 1404 - 1412. [Abstract] [Full Text] [PDF]

				P. S. Pagel, D. A. Hettrick, M. W. Montgomery, J. R. Kersten, R. P. Steffen, and D. C. Warltier RSR13, a Synthetic Modifier of Hemoglobin-Oxygen Affinity, Enhances the Recovery of Stunned Myocardium in Anesthetized Dogs J. Pharmacol. Exp. Ther., April 1, 1998; 285(1): 1 - 8. [Abstract] [Full Text]

				R. S. Richardson, K. Tagore, L. J. Haseler, M. Jordan, and P. D. Wagner Increased VO2 max with right-shifted Hb-O2 dissociation curve at a constant O2 delivery in dog muscle in situ J Appl Physiol, March 1, 1998; 84(3): 995 - 1002. [Abstract] [Full Text] [PDF]