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Assessing Cerebral Autoregulation via Oscillatory Lower Body Negative Pressure and Projection Pursuit Regression
Published on: December 10, 2014
Plasma viscosity and cerebral blood flow
Y Tomiyama1, J E Brian, M M Todd
1Department of Anesthesia, University of Iowa College of Medicine, Iowa City, Iowa 52242, USA.
American Journal of Physiology. Heart and Circulatory Physiology
|September 29, 2000
Summary
Plasma viscosity significantly impacts cerebral blood flow (CBF), especially under high-flow conditions. Higher plasma viscosity reduces CBF, suggesting it
Area of Science:
- Physiology
- Hemodynamics
- Neuroscience
Background:
- Cerebral blood flow (CBF) regulation is crucial for brain function.
- The influence of blood viscosity on CBF is not fully understood, particularly under varying physiological conditions.
Purpose of the Study:
- To investigate the relationship between plasma viscosity and CBF.
- To determine if baseline CBF influences the effect of viscosity on CBF.
- To identify whether plasma viscosity or whole blood viscosity is more critical in regulating CBF.
Main Methods:
- Rats underwent exchange transfusion to alter plasma viscosity to 1.0 or 3.0 cP.
- Cortical CBF was measured using H(2) clearance.
- CBF was assessed under normoxic, anemic, hypercapnic, and hypoxic conditions.
Main Results:
- At baseline, CBF was similar across groups (49.4 +/- 10.2 ml/100g/min).
- In control conditions, viscosity changes had no significant effect on CBF.
- Under high-flow states (hemodilution, hypercapnia, hypoxia), a plasma viscosity of 1.0 cP yielded high CBF (98-115 ml/100g/min), while 3.0 cP significantly reduced CBF (56-58 ml/100g/min).
Conclusions:
- The impact of blood viscosity on CBF is greater during high-flow states.
- Plasma viscosity appears to be a more critical determinant of CBF regulation than whole blood viscosity.
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