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Transmural pressures and tissue perfusion in man.
1Department of Medicine B, Hillerød Hospital, Denmark.
Acta Physiologica Scandinavica. Supplementum
|January 1, 1991
Summary
Blood flow ceases when diastolic arterial pressure drops to zero, even with a positive pressure head, due to arterio-arteriolar collapse. Transmural pressure changes equally affect arterial and venous beds, except during external compression causing venous collapse.
Area of Science:
- Cardiovascular Physiology
- Hemodynamics
Background:
- The Hagen-Poiseuille principle describes the relationship between pressure gradient and blood flow.
- Understanding transmural pressure effects on blood flow is crucial for cardiovascular research.
Purpose of the Study:
- To reinvestigate the Hagen-Poiseuille principle by comparing transmural pressure changes.
- To analyze blood flow responses to internal versus external pressure variations in human limbs.
Main Methods:
- Utilized the 133Xenon washout technique to measure blood flow in human subcutaneous and skeletal muscle.
- Manipulated intramural pressure via leg position and exercise.
- Induced extramural pressure changes using a leg cuff.
Main Results:
- Blood flow stopped when local diastolic arterial pressure reached zero, despite a positive pressure head, attributed to arterio-arteriolar collapse.
- Transmural pressure changes similarly impacted arterial and venous sections.
- External compression in a supine position increased blood flow resistance due to postcapillary venous collapse.
Conclusions:
- Transmural pressure changes, whether internal or external, have consistent effects on the vascular bed.
- Postcapillary venous collapse is a significant factor influencing blood flow resistance during external compression.