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Erythrocyte deformability measured by filtrometry: Influences of variations in filtration pressure, MCV and MCHC
Department of Internal Medicine, University Hospital, Lund, Sweden.
Department of Internal Medicine, University Hospital, Lund, Sweden.
1993 (English)In: Clinical Hemorheology, ISSN 0271-5198/93, Vol. 13, p. 791-801Article in journal (Refereed) Published
Abstract [en]

Abstract

 Erythrocyte deformability can be measured as filterability through a polycarbonate filter. To evaluate the influence of variations in filtration pressures the present study was performed as filtration of red cell suspensions with a pore size of 5 μm at constant negative pressures of -10, -20, -30, -40 and -50 mm H2O in the St. George's Filtrometer. Filtration parameters were expressed as passage time, flow rate, flow resistance, initial relative filtration rate (IrFR), red cell transit time (RCTT) and clogging particles (CP). Passage time was decreased and flow rate was increased significantly at all filtration pressures compared to preceding pressure level (p<0.001). In the pressure range -10 to -30 mm H2O flow resistance decreased significantly (p<0.001), but was almost constant in the range -30 to -50 mm H2O. Also IrFR and RCTT showed a significantly greater change (p<0.001) when the pressure was increased from -10 to -20 mm H2O compared to the same pressure change in the range -30 to -50 mm H2O. CP varied more with pressure, but the greatest change was found in the range -10 to -20 mm H2O. Variations of MCV within the normal range were associated with changes in passage time, flow resistance and CP in the pressure range -20 to -50 mm H2O.

It is concluded that the filtration pressure is an important factor in studies on blood cell filterability. For the St. George's Filtrometer the optimal pressure range seems to be -30 to -50 mm H2O.

Key words:  Erythrocyte filterability; Filtration test; Stress factors; Filtration pressure; Wall shear stress;  Mean corpuscular volume; Mean corpuscular haemoglobin concentration.  

 

Place, publisher, year, edition, pages
New York, USA: Pergamon Press , 1993. Vol. 13, p. 791-801
Keywords [en]
Erythrocyte filterability; Filtration test; Stress factors; Filtration pressure; Wall shear stress; Mean corpuscular volume; Mean corpuscular haemoglobin concentration.
National Category
Medical and Health Sciences
Research subject
Natural Science, Biomedical Sciences; Health and Caring Sciences, Caring Science
Identifiers
URN: urn:nbn:se:lnu:diva-11709OAI: oai:DiVA.org:lnu-11709DiVA, id: diva2:417247
Available from: 2011-05-16 Created: 2011-05-16 Last updated: 2011-09-14Bibliographically approved
In thesis
1. Erythrocyte deformability studies by viscometry and filtrometry
Open this publication in new window or tab >>Erythrocyte deformability studies by viscometry and filtrometry
1994 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

DOCTORAL DISSERTATION 

Abstract

The present thesis concerns factors of major importance in filtrometric studies of human erythrocytes, e.g. influence of buffer media, importance of filtration pressure for filtration through micropores and possible effects of damaged and hemolyzed blood cells. The reproducibility of results from haemorheological studies has also been studied. Furthermore the rheological effects on erythrocytes from experimental, functional manipulation have been studied, e.g. by adding of digitalis glycosides and corticosteroids. Finally, the rheological properties of blood, that has been stored in frozen form, have been evaluated.

The first paperof this thesis shows that red cell morphology, flow behaviour and also the reproducibility of measurements are strongly dependent on the composition of the surrounding buffer medium.

Paper 2points out the importance of a carefully chosen filtration pressure to make the experimental settings to come as close to the in vivo capillary circulatory conditions as possible. Influence from variations in MCV is also demonstrated in this paper.

In paper 3the function of the sodium/potassium pump has, by adding of ouabain, been interfered with, thus creating changes of the intracellular ion and charge conditions. This, in turn, influences on blood viscosity. When incubating erythrocytes with calcium ions a more direct effect on erythrocyte deformability is seen.

In paper 4is described the complex effect of corticosteroids on flow properties of red blood cells. Thus it is shown that the over all effect of adding a corticosteroid to a suspension of blood cells seems to be a decreased viscosity, in spite of the fact that a reduced deformability of red blood cells can be seen as a parallel phenomenon.

Finally, paper 5indicates that the damage caused on red blood cells during preservation by glycerol and in frozen form may be of a haemorheological kind. Filtration through micropores seem: to be an adequate method for evaluation of damage caused to cells by freezing and parallels to the in vivo conditions in the spleen can be seen. The St George's Filtrometer, which was used in this study, seems to be able to find damaged cells in as low concentrations as 1/1000.

It is concluded that a buffer solution, with a small amount of albumin added should be used in studies on filterability of red blood cells. It is also concluded that the cells are sensible to the pressure conditions used in the filtration process. A negative pressure around 30 mm H20 seems to be suitable in this type of filtration studies. Haemorheological effects of digitalis glycosides and corticosteroids are elucidated and so is the effect of blood preservation through glycerol treatment and freezing on red blood cells.

Place, publisher, year, edition, pages
Lund, Sweden: Lunds Universitet, 1994. p. 110
Series
ISRN LUMEDW/MEMA--1042--SE
Keywords
Erythrocyte deformability; viscometry; Filtrometry; Red cell membrane; Buffer; Filtration pressure; stress factors; Mean corpuscular volume; Sodium-potassium pump, Ouabain, Corticosteroids; Blood storage; Transfusion
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:lnu:diva-11785 (URN)
Public defence
1994-06-08, Föreläsningssal 3, Centralblocket, Universitetssjukhuset i Lund, Lund, 09:00 (Swedish)
Opponent
Supervisors
Note
Doktorsexamen i experimentell medicinAvailable from: 2011-06-07 Created: 2011-05-19 Last updated: 2011-06-07Bibliographically approved

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Persson, Sylvi Ulrika

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