Effect of increased whole blood viscosity on regional blood flows in chronically hypoxemic lambs
| Autor: | W. G. Zijlstra, Jaap R. G. Kuipers, J. Van Der Meer, M. Dalinghaus, J. W. C. Gratama, Hennie Knoester |
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| Rok vydání: | 1994 |
| Předmět: |
medicine.medical_specialty
Physiology Blood viscosity Hemodynamics Hematocrit Coronary Circulation Physiology (medical) Internal medicine medicine Animals Hypoxia Sheep medicine.diagnostic_test business.industry Blood flow Hypoxia (medical) Blood Viscosity Microspheres Endocrinology medicine.anatomical_structure Cerebral blood flow Regional Blood Flow Cerebrovascular Circulation Anesthesia Blood Circulation Chronic Disease Vascular resistance Vascular Resistance Hemoglobin medicine.symptom Cardiology and Cardiovascular Medicine business |
| Zdroj: | American Journal of Physiology-Heart and Circulatory Physiology. 267:H471-H476 |
| ISSN: | 1522-1539 0363-6135 |
| Popis: | In chronic hypoxemia blood flow and oxygen supply to vital organs are maintained, but to nonvital organs they are decreased. We measured organ blood flows (microspheres) and whole blood viscosity in 10 chronically hypoxemic lambs, with an atrial septal defect and pulmonary stenosis, and in 8 control lambs. Vascular hindrance (resistance/viscosity) was calculated to determine to what extent the effect of increased blood viscosity on organ blood flow was compensated for by a decrease in vascular tone. Arterial oxygen saturation was decreased (68 +/- 10 vs. 91 +/- 3%, P < 0.001), and both hemoglobin concentration (145 +/- 10 vs. 109 +/- 9 g/l, P < 0.05) and blood viscosity (4.4 +/- 0.6 vs. 3.6 +/- 0.6 mPa.s, P < 0.05) were increased in hypoxemic lambs. Systemic blood flow, oxygen supply, oxygen uptake, and blood pressures were not significantly different between hypoxemic and control lambs. Myocardial and cerebral blood flow was maintained in hypoxemic lambs, whereas renal, gastrointestinal, splenic, and thyroidal blood flows were at least 30% lower. Vascular hindrance was significantly decreased in the myocardium and tended to be lower in the brain of hypoxemic lambs, but in all other organs it was similar to that in control lambs. It is concluded that blood flow is redistributed in chronic hypoxemia in lambs; myocardial and cerebral blood flow is maintained, whereas blood flow to splanchnic organs, the kidneys, and the thyroids is decreased. The decreased blood flow to organs is a consequence of the increased whole blood viscosity. |
| Databáze: | OpenAIRE |
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