Oxygen delivery at high blood viscosity and decreased arterial oxygen content to brains of conscious rats
| Autor: | A. Rebel, Klaus F. Waschke, K. van Ackern, Wolfgang Kuschinsky, H. Krieter, C. Lenz |
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| Rok vydání: | 2001 |
| Předmět: |
Male
medicine.medical_specialty Physiology Anemia Blood viscosity Hemodynamics Microcirculation Rats Sprague-Dawley Physiology (medical) Internal medicine medicine Animals Wakefulness Chemistry Brain Povidone Biological Transport Cerebral Arteries Blood Viscosity medicine.disease Rats Oxygen Vasodilation Endocrinology medicine.anatomical_structure Hematocrit Cerebral blood flow Cerebrovascular Circulation Anesthesia Circulatory system Cardiology and Cardiovascular Medicine Antipyrine Blood Flow Velocity Blood vessel Artery |
| Zdroj: | American Journal of Physiology-Heart and Circulatory Physiology. 280:H2591-H2597 |
| ISSN: | 1522-1539 0363-6135 |
| DOI: | 10.1152/ajpheart.2001.280.6.h2591 |
| Popis: | We addressed the question to which extent cerebral blood flow (CBF) is maintained when, in addition to a high blood viscosity (Bvis) arterial oxygen content (CaO2 ) is gradually decreased. CaO2 was decreased by hemodilution to hematocrits (Hct) of 30, 22, 19, and 15% in two groups. One group received blood replacement (BR) only and served as the control. The second group received an additional high viscosity solution of polyvinylpyrrolidone (BR/PVP). Bvis was reduced in the BR group and was doubled in the BR/PVP. Despite different Bvis, CBF did not differ between BR and BR/PVP rats at Hct values of 30 and 22%, indicating a complete vascular compensation of the increased Bvis at decreased CaO2 . At an Hct of 19%, local cerebral blood flow (LCBF) in some brain structures was lower in BR/PVP rats than in BR rats. At the lowest Hct of 15%, LCBF of 15 brain structures and mean CBF were reduced in BR/PVP. The resulting decrease in cerebral oxygen delivery in the BR/PVP group indicates a global loss of vascular compensation. We concluded that vasodilating mechanisms compensated for Bvis increases thereby maintaining constant cerebral oxygen delivery. Compensatory mechanisms were exhausted at a Hct of 19% and lower as indicated by the reduction of CBF and cerebral oxygen delivery. |
| Databáze: | OpenAIRE |
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