The measurement of and factors affecting the viscosity of blood
The measurement of and factors affecting the viscosity of blood
Blood viscosity is a parameter that has been of clinical interest for many centuries. The degree of interest has varied, and this relates directly to the hope offered by new instruments, and the subsequent disappointment felt with their performance. It is the conclusion of this study that the technology now exists to provide a precise measurement of blood viscosity. However, the factors that affect it must be identified and where possible controlled. A systematic study of the factors involved has been undertaken. This has entailed the analysis of an applied shear stress rheometer. The application of this type of viscometer to the measurement of whole blood viscosity has not previously been assessed. The physical factors which affect measurement have been examined. These include the design of the measurement unit; the method of applying shear; temperature effects; and sedimentation effects which occur under shear. This investigation led initially to alterations in the rheometer's construction, and culminated in the production of a standard method, substantially reducing the measurements technical error. The second line of enquiry investigated the effect played on viscosity by blood's constituents. This examined the contribution made by the cellular and the plasma protein elements present in whole blood. The results of this enquiry have shown that both qualitative and quantitative changes in the red cell affect viscosity; the viscous properties of the white cells is dependent on the cell type; the viscous contribution of the plasma proteins varies depending on the degree of protein - red cell interaction. The modified rheometer is the most sensitive instrument reported for the measurement of blood's viscosity. The results show that the measurement of whole blood viscosity is no longer limited by technical error. The parameter can be measured with precision, in a clinical laboratory, providing physical factors are controlled. Further study into the parameters that control whole blood flow are required, however it is unlikely that more information can be obtained using viscometry.
University of Southampton
Davenport, Peter
7cb03c14-e420-4ed7-a886-d551fe213baf
1988
Davenport, Peter
7cb03c14-e420-4ed7-a886-d551fe213baf
Davenport, Peter
(1988)
The measurement of and factors affecting the viscosity of blood.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Blood viscosity is a parameter that has been of clinical interest for many centuries. The degree of interest has varied, and this relates directly to the hope offered by new instruments, and the subsequent disappointment felt with their performance. It is the conclusion of this study that the technology now exists to provide a precise measurement of blood viscosity. However, the factors that affect it must be identified and where possible controlled. A systematic study of the factors involved has been undertaken. This has entailed the analysis of an applied shear stress rheometer. The application of this type of viscometer to the measurement of whole blood viscosity has not previously been assessed. The physical factors which affect measurement have been examined. These include the design of the measurement unit; the method of applying shear; temperature effects; and sedimentation effects which occur under shear. This investigation led initially to alterations in the rheometer's construction, and culminated in the production of a standard method, substantially reducing the measurements technical error. The second line of enquiry investigated the effect played on viscosity by blood's constituents. This examined the contribution made by the cellular and the plasma protein elements present in whole blood. The results of this enquiry have shown that both qualitative and quantitative changes in the red cell affect viscosity; the viscous properties of the white cells is dependent on the cell type; the viscous contribution of the plasma proteins varies depending on the degree of protein - red cell interaction. The modified rheometer is the most sensitive instrument reported for the measurement of blood's viscosity. The results show that the measurement of whole blood viscosity is no longer limited by technical error. The parameter can be measured with precision, in a clinical laboratory, providing physical factors are controlled. Further study into the parameters that control whole blood flow are required, however it is unlikely that more information can be obtained using viscometry.
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Published date: 1988
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Local EPrints ID: 462760
URI: http://eprints.soton.ac.uk/id/eprint/462760
PURE UUID: 425d8469-5f7e-45a7-943d-f2c694f7f5b4
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Date deposited: 04 Jul 2022 19:51
Last modified: 04 Jul 2022 19:51
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Author:
Peter Davenport
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