Effects of a sudden flow reduction on red blood cell rouleau formation and orientation using RF backscattered power.
Abstract: In most studies that were aimed at evaluating the kinetics of red blood cell (RBC) aggregation, human blood was initially circulated at a high shear rate to disrupt the aggregates, and measurements were performed following a complete flow stoppage, during the process of rouleau formation. However, it is known that a very low shear rate can enhance the formation of aggregates, as demonstrated by the modal relationship of the shear-rate dependence of RBC aggregation. The objective of the present study was, thus, to evaluate the influence of sudden flow reductions compared to a complete flow stoppage on the kinetics of rouleau formation, using ultrasound backscattering. Horse blood models, characterized by different aggregation levels, were obtained by diluting the plasma with a saline solution in different proportions. Blood was circulated in a 12.7-mm vertical tube at a flow rate of 1250 mL min-1 (prereduction flow rate) to disrupt the aggregates. The ultrasound radiofrequency (RF) signal was recorded from the center of the tube following different levels of sudden flow reduction or complete stoppage (postreduction flow rate). All measurements were performed over 2 min, using a 10-MHz transducer. No power increase was observed after complete flow stoppage. For postreduction flow rates varying between 20 and 160 mL min-1, the backscattered power increased proportionally with the kinetics of RBC aggregation. The echo buildup was also faster and stronger when the postreduction flow rate was increased. An unexpected pattern of variation of the backscattered power was found for horse RBCs characterized by high kinetics of rouleau formation. The power increased rapidly to a plateau, followed by another rapid increase and another plateau. Rouleau formation, random disorientation and reorientation were postulated to explain the phasic power increases observed.
Publication Date: 1998-07-04 PubMed ID: 9651960DOI: 10.1016/s0301-5629(98)00019-2Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This study investigates the effects of sudden flow reductions versus a complete flow stoppage on the formation and orientation of RBC aggregates, or rouleau formation, using ultrasound backscattering. This was conducted through various experimentations on horse blood models.
Study Approach
In trying to assess the impact of flow reductions on red blood cell (RBC) aggregation, human blood was typically utilized. It was circulated at a high shear rate to disrupt the aggregates with measurements taken once the flow is completely stopped during the process of rouleau formation. This study, however, recognizes that a very low shear rate could also facilitate the formation of aggregates, hence the adoption of the approach to investigate both scenarios.
- The research aim was to understand the impact of abrupt flow reductions against a total flow stoppage on the kinetics or the rate of rouleau formation.
- The researchers used ultrasound backscattering as a tool to investigate this phenomenon.
- To represent different aggregation levels, horse blood models were used instead of human blood. This was achieved through the dilution of plasma with saline in different proportions.
- The blood was circulated at a rate of 1250 mL min-1 before reduction to fracture the aggregates.
Experiments and Observations
Using a 10-MHz transducer, the ultrasound radiofrequency (RF) signal was recorded from the tube’s center after instituting different levels of sudden flow reduction or total flow stoppage.
- It was observed that there was no increase in power following a complete stoppage of flow.
- However, when post reduction flow rates varied between 20 and 160 mL min-1, there was a proportional increase in the backscattered power mirroring the kinetics of RBC aggregation.
- There was a quicker and stronger echo build-up when the post-reduction flow rate was increased.
- For horse RBCs exhibiting high rouleau formation kinetics, an unusual pattern of backscattered power variation was noticed. This pattern involved a rapid power elevation to a plateau, then another quick increase and another plateau.
- To explain the power increases observed, rouleau formation, random disorientation and reorientation were postulated.
This study sheds new light on the relationship between blood flow rate reductions and the kinetics of rouleau formation, demonstrating the importance of flow velocity in the aggregation of red blood cells. It could have significant implications for understanding various pathological conditions in human beings where the aggregation or clumping of red blood cells is involved.
Cite This Article
APA
Qin Z, Durand LG, Allard L, Cloutier G.
(1998).
Effects of a sudden flow reduction on red blood cell rouleau formation and orientation using RF backscattered power.
Ultrasound Med Biol, 24(4), 503-511.
https://doi.org/10.1016/s0301-5629(98)00019-2 Publication
Researcher Affiliations
- Laboratory of Biomedical Engineering, Institut de recherches cliniques de Montréal, Canada.
MeSH Terms
- Analysis of Variance
- Animals
- Blood Flow Velocity / physiology
- Blood Viscosity
- Erythrocyte Aggregation / physiology
- Hemorheology
- Horses
- Kinetics
- Ultrasonics
Citations
This article has been cited 5 times.- Lanotte L, Mauer J, Mendez S, Fedosov DA, Fromental JM, Claveria V, Nicoud F, Gompper G, Abkarian M. Red cells' dynamic morphologies govern blood shear thinning under microcirculatory flow conditions. Proc Natl Acad Sci U S A 2016 Nov 22;113(47):13289-13294.
- Yazdani A, Li X, Em Karniadakis G. Dynamic and rheological properties of soft biological cell suspensions. Rheol Acta 2016 Jun;55(6):433-449.
- Fedosov DA, Dao M, Karniadakis GE, Suresh S. Computational biorheology of human blood flow in health and disease. Ann Biomed Eng 2014 Feb;42(2):368-87.
- Park DW, Kruger GH, Rubin JM, Hamilton J, Gottschalk P, Dodde RE, Shih AJ, Weitzel WF. In vivo vascular wall shear rate and circumferential strain of renal disease patients. Ultrasound Med Biol 2013 Feb;39(2):241-52.
- Fedosov DA, Pan W, Caswell B, Gompper G, Karniadakis GE. Predicting human blood viscosity in silico. Proc Natl Acad Sci U S A 2011 Jul 19;108(29):11772-7.
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