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Oxygen release from arterioles with normal flow and no-flow conditions
Pedro Cabrales1, Amy G Tsai, Paul C Johnson
1La Jolla Bioengineering Institute, University of California-San Diego, La Jolla, CA 92037, USA. pcabrales@ucsd.edu
Journal of Applied Physiology (Bethesda, Md. : 1985)
|December 31, 2005
Summary
Arteriolar oxygen release is 53% higher during blood flow than no-flow. Hemodilution further increases oxygen release and consumption by the vessel wall, highlighting the impact of wall shear stress on oxygen delivery.
Area of Science:
- Microcirculation physiology
- Vascular biology
- Oxygen transport
Background:
- Arterioles play a crucial role in regulating oxygen supply to tissues.
- Understanding oxygen release dynamics from arterioles is vital for comprehending tissue oxygenation.
- Previous studies have not fully elucidated the impact of flow conditions and hemodilution on arteriolar oxygen release.
Purpose of the Study:
- To quantify oxygen release rates from arterioles under flow and no-flow conditions.
- To investigate the effects of acute hemodilution on arteriolar oxygen release and microcirculation oxygen extraction.
- To assess the oxygen cost associated with wall shear stress in arterioles.
Main Methods:
- Utilized the hamster window chamber model for in vivo microcirculation studies.
- Measured intra-arteriolar oxygen tension (Po2) using phosphorescence quenching of Pd-porphyrin.
- Induced no-flow conditions via microvascular occlusion and performed acute hemodilution with dextran 70.
Main Results:
- Oxygen release from arterioles was 53% greater during flow compared to no-flow conditions.
- Acute hemodilution significantly increased arteriolar oxygen release (39%) and microcirculation oxygen extraction (33%).
- Hemodilution led to increased wall shear stress and a greater oxygen consumption by the vessel wall.
Conclusions:
- Arteriolar oxygen release is significantly influenced by blood flow dynamics.
- Hemodilution alters microcirculatory oxygen transport, increasing both release and consumption.
- Wall shear stress may account for a substantial portion of the oxygen cost in arterioles during flow.
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