Clinical measurement of whole-blood viscosity at low-shear rates

2016 ◽  
Vol 1 (2) ◽  
pp. 167-177 ◽  
Author(s):  
T.C. McN. Inglis ◽  
P.J. Carson ◽  
J. Stuart
Keyword(s):  
Blood Viscosity ◽  
Whole Blood ◽  
Clinical Measurement ◽  
Whole Blood Viscosity ◽  
Shear Rates ◽  
Low Shear

scholarly journals Hydroxyurea Improves Oxygen Transport Effectiveness in Sickle Cell Anemia Patients

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 2716-2716
Author(s):  
Vivien A. Sheehan ◽  
Sheryl Nelson ◽  
Caroline Yappan ◽  
Bogdan R. Dinu ◽  
Danielle Guffey ◽  
...  
Keyword(s):  
Blood Flow ◽  
Sickle Cell ◽  
Blood Viscosity ◽  
Whole Blood ◽  
Patient Characteristics ◽  
Whole Blood Viscosity ◽  
Shear Rates ◽  
High Shear Rates ◽  
Altered Blood ◽  
Low Shear

Abstract Background: Sickle cell disease (SCD) patients have altered blood rheology due to erythrocyte abnormalities, including increased aggregation and reduced deformability, which together affect microcirculatory blood flow and tissue perfusion. At equal hematocrit, sickle cell blood viscosity is increased compared to normal individuals. The hematocrit to viscosity ratio (HVR) is a measure of red blood cell (RBC) oxygen carrying capacity, and is reduced in SCD with clinical consequences related to altered blood flow and reduced tissue oxygenation. Erythrocyte transfusions reduce HVR at low shear rates that mimic venous circulation, and do not change HVR at high shear rates that mimic arterial blood flow. Hydroxyurea is a safe and effective therapy for SCD; however, its effects on sickle cell rheology and HVR have not been fully investigated. Evaluating the effects of hydroxyurea on viscosity is especially critical, before its use is extended widely to patients with cerebrovascular disease or genotypes with higher hematocrit and higher viscosity such as Hemoglobin SC (HbSC). Methods: To determine the effects of hydroxyurea on viscosity and HVR, we designed a prospective study to measure whole blood viscosity at 45 s-1 (low shear) and 225 s-1(high shear) rates in pediatric patients with SCD using a Brookfield cone and plate viscometer under oxygenated conditions. Venous blood samples (1-3mL) were collected in EDTA and analyzed no more than 4 hours after phlebotomy; samples were run in duplicate by persons blinded to the patient’s sickle genotype and treatment status. Laboratory values were obtained using an ADVIA hematology analyzer. Samples were analyzed from three non-overlapping cohorts of patients with SCD and HbAA individuals for comparison: untreated HbSS patients (n= 43), HbSS patients treated with hydroxyurea at maximum tolerated dose (n=98), untreated HbSC patients (n=53) and HbAA patients (n=19). Laboratory parameters that differed significantly among the SCD groups were analyzed by simple linear regression. Results: Patient characteristics and viscosity measurements are shown in the Table. Within the SCD population, the viscosity was lowest among the untreated HbSS patients, presumably due to their low hematocrit, while viscosity was higher in HbSS patients on hydroxyurea and HbSC patients. When the HVR was calculated for each group, no significant difference was identified between untreated HbSS and untreated HbSC patients. However, hydroxyurea treatment significantly increased HVR at both 45s-1 and 225 s-1 (p<0.001), indicating that the slightly increased viscosity in this cohort was more than compensated by a higher hematocrit. Correlations were tested for hemoglobin (Hb), mean corpuscular volume (MCV), white blood cell count (WBC), absolute neutrophil count (ANC), absolute reticulocyte count (ARC), % fetal hemoglobin (HbF), and average red cell density in g/dL with HVR, at both shear rates. The hydroxyurea-associated HVR increase at both shear rates was independent of %HbF or MCV, but the increased HVR at 225 s-1was associated with lower WBC (p<0.001), lower ANC (p=0.002), and lower red cell density (p=.009). Conclusions: We provide prospective data on whole blood viscosity measurements in a large cohort of children with SCD. Hydroxyurea increases the hematocrit in HbSS patients more than the viscosity, and thus improves HVR. These findings imply that hydroxyurea improves RBC oxygen transport at both high and low shear rates, which should confer clinical benefits, and these effects are independent of HbF induction. Concerns about hydroxyurea increasing whole blood viscosity and reducing tissue oxygenation in children with cerebrovascular disease or HbSC patients may not be warranted, if the same beneficial HVR effects are achieved. Abstract 2717. Table 1. Patient characteristics. Viscosity was typically measured in duplicate and averaged for each patient. HVR at 45 s-1 and 225s-1 was calculated as hematocrit/viscosity. Results are presented as mean ± 2SD. HbAAn=19 HbSS, untreatedn=43 HbSS, on Hydroxyurean=98 HbSCn=53 Age (years) 15.4 ± 3.8 10.4 ± 5.1 10.7 ± 3.4 10.5 ± 4.3 Hemoglobin (gm/dL) 13.5 ± 1.7 8.5 ± 1.0 9.9 ± 1.4 11.0 ± 1.2 Hematocrit (%) 40.9 ± 5.3 25.5 ± 3.1 28.4 ± 3.7 31.3 ± 3.2 Viscosity (cP) at 45s-1 5.3 ± 0.9 4.6 ± 1.2 4.3 ± 0.9 5.5 ±0.9 HVR at 45s-1 7.5 ± 0.9 5.8 ± 1.1 6.75 ± 1.0 5.77 ± 0.7 Viscosity (cP) at 225s-1 3.8 ± 0.5 3.3 ± 0.5 3.4 ± 0.5 4.1 ± 0.5 HVR at 225s-1 10.3 ± 0.7 7.7 ± 0.8 8.53 ± 0.8 7.72 ± 0.6 Disclosures Off Label Use: Hydroxyurea is not FDA approved for use in pediatric sickle cell patients.

Whole blood viscosity in the evaluation of thrombogenic milieu in mitral stenosis

2021 ◽  
Vol 15 (3) ◽  
pp. 181-190
Author(s):  
Elif H Ozcan Cetin ◽  
Mehmet S Cetin ◽  
Mustafa B Ozbay ◽  
Hasan C Könte ◽  
Nezaket M Yaman ◽  
...  
Keyword(s):  
Shear Rate ◽  
Blood Viscosity ◽  
Whole Blood ◽  
Mitral Stenosis ◽  
High Shear Rate ◽  
High Shear ◽  
Whole Blood Viscosity ◽  
Spontaneous Echo Contrast ◽  
Shear Rates ◽  
Low Shear

Aim: We aimed to assess the association of whole blood with thromboembolic milieu in significant mitral stenosis patients. Methodology & results: We included 122 patients and classified patients into two groups as having thrombogenic milieu, thrombogenic milieu (+), otherwise patients without thrombogenic milieu, thrombogenic milieu (-). Whole blood viscosity (WBV) in both shear rates were higher in thrombogenic milieu (+) group comparing with thrombogenic milieu (-). WBV at high shear rate and WBV at low shear rate parameters were moderately correlated with grade of spontaneous echo contrast. Adjusted with other parameters, WBV parameters at both shear rates were associated with presence of thrombogenic milieu. Discussion & conclusion: We found that extrapolated WBV at both shear rates was significantly associated with the thrombogenic milieu in mitral stenosis. This easily available parameter may provide additional perspective about thrombogenic diathesis.

Increased Whole Blood Viscosity during Coronary Artery Bypass Surgery

1990 ◽  
Vol 63 (01) ◽  
pp. 006-012 ◽  
Author(s):  
Robert L Hunter ◽  
Christine Papadea ◽  
Christopher J Gallagher ◽  
Donald C Finlayson ◽  
Irene J Check
Keyword(s):  
Blood Viscosity ◽  
Whole Blood ◽  
Bypass Surgery ◽  
Artery Bypass ◽  
Whole Blood Viscosity ◽  
Poloxamer 188 ◽  
Soluble Fibrin ◽  
Shear Rates ◽  
Low Shear

SummaryThis study was designed to test the hypothesis that soluble fibrin complexes resulting from the trauma of surgery could produce elevated blood viscosity, to characterize the soluble fibrin polymers, and to evaluate in vitro the effect of a new hemorheologic agent, poloxamer 188, on viscosity in these abnormal situations. Ten patients undergoing aortocoronary bypass surgery were studied before and at various times after surgery. By 6 h after surgery, the mean hematocrit decreased by 23%, fibrinogen decreased 48%, and erythrocyte sedimentation rate decreased 33%, whole blood viscosity at a low shear rate rose on average of 69% and soluble fibrin rose 118%. Over the 6-day observation period, the concentrations of soluble fibrin paralleled the changes in viscosity, whereas the concentrations of fibrinogen varied nearly inversely with viscosity. The effects of various forms of fibrinogen and fibrin were tested by additions to normal blood. Soluble fibrin polymers, but not fibrin monomers, increased blood viscosity two to three fold. Poloxamer 188 reduced the viscosity of all patient samples to the normal range. These data support the hypothesis that increased whole blood viscosity at low shear rates is caused by hydrophobic adhesion of fibrin polymers to red cells and that poloxamer 188 normalizes viscosity by effectively disrupting the weak hydrophobic bonds.

Changes in Whole Blood Viscosity at Low Shear Rates Correlate with Intravascular Volume Changes during Hemodialysis

2012 ◽  
Vol 35 (6) ◽  
pp. 425-434 ◽  
Author(s):  
Won Kim ◽  
Sung Kwang Park ◽  
Kyung Pyo Kang ◽  
Dong Hwan Lee ◽  
Sam Yeon Kim ◽  
...  
Keyword(s):  
Shear Rate ◽  
Blood Volume ◽  
Blood Viscosity ◽  
Whole Blood ◽  
High Shear ◽  
Whole Blood Viscosity ◽  
Shear Rates ◽  
Before And After ◽  
The Relationship ◽  
Low Shear

Background: Elevated blood viscosity has been shown to be independently correlated with cardiovascular risk factors and associated with increased risk of major cardiovascular events, including death and acute myocardial infarction. The aim of the present study was to investigate changes in whole blood viscosity (WBV) at shear rates of 1, 5, and 300 s-1 before and after hemodialysis in patients with end-stage renal disease (ESRD). We also examined the relationship between the changes of WBV and intravascular blood volume. Methods: 43 patients with ESRD receiving maintenance hemodialysis were enrolled. WBV was measured using a scanning capillary tube viscometer pre- and post-dialysis to quantify dialytic viscosity surges. Body weight, blood pressure, and hematocrit were also measured before and after hemodialysis, as was the fluid removed during the session. Results: Hemodialysis had a 3 times greater impact on the low-shear WBV at a shear rate of 1 s-1 (i.e., 44.1% change) than on the high-shear WBV at a shear rate of 300 s-1 (i.e., 15.9% change). Changes in the low-shear WBV obtained at shear rates of 1 and 5 s-1 during hemodialysis were significantly correlated with changes in hematocrit. The intravascular blood volume reduction during hemodialysis was positively correlated with the changes in both high-shear and low-shear WBVs. Conclusions: These results suggest that the WBV parameter may hold additional information beyond hemoconcentration. Further research is needed to evaluate the relationship between low-shear WBV surges and increased morbidity in the patient population with ESRD.

The influence of lipoproteins on whole-blood viscosity at multiple shear rates

Metabolism ◽  
2005 ◽  
Vol 54 (6) ◽  
pp. 764-768 ◽  
Author(s):  
Arnold Slyper ◽  
Anh Le ◽  
Jason Jurva ◽  
David Gutterman
Keyword(s):  
Blood Viscosity ◽  
Whole Blood ◽  
Whole Blood Viscosity ◽  
Shear Rates

Blood Electrical Impedance Closely Matches Whole Blood Viscosity as Parameter of Hemorheology and Inflammation

2003 ◽  
Vol 13 (6) ◽  
pp. 305-312 ◽  
Author(s):  
G.A.M. Pop ◽  
W.J. Hop ◽  
L. Moraru ◽  
M. van der Jagt ◽  
J. Quak ◽  
...  
Keyword(s):  
Shear Rate ◽  
Blood Cell ◽  
Blood Viscosity ◽  
Whole Blood ◽  
Cell Aggregation ◽  
Whole Blood Viscosity ◽  
Red Blood Cell Aggregation ◽  
Exponential Increase ◽  
Blood Impedance ◽  
Low Shear

AbstractRed blood cell aggregation (RBCa) is a sensitive inflammation marker. RBCa determination from erythrocyte sedimentation rate, ESR, is used since long, but is unspecific unless corrected for hematocrit, Ht. Whole blood viscosity measurement at low shear rate is also sensitive to RBCa but is cumbersome to apply. To investigate whether electrical blood impedance, being sensitive to spatial red cell distribution, can be a good alternative to determine RBCa in low shear conditions. Blood was collected from 7 healthy volunteers. From each 16 different samples were prepared with 4 different Ht’s and with 4 different fibrinogen concentrations. Viscosity was measured at low shear rate (4.04 s-1) with a rotational viscometer at 37˚C. Electrical blood impedance was measured during similar shear conditions and temperature in a specially designed cuvette. ESR was determined according to Westergren. A logarithmic increase of viscosity as well as of capacitance, Cm, is seen when fibrinogen rises and an exponential increase when Ht rises. However, ESR shows a logarithmic decrease with increasing Ht and an exponential increase when fibrinogen rises. The viscosity could be accurately described using an exponential model. Under similar low shear conditions and temperature in-vitro, either whole blood viscosity or electrical blood capacitance reflect red blood cell aggregation due to fibrinogen and Ht variation in a similar way.

Prognostic impact of low-shear whole blood viscosity in hypertensive men

2005 ◽  
Vol 35 (2) ◽  
pp. 93-98 ◽  
Author(s):  
G. Ciuffetti ◽  
G. Schillaci ◽  
R. Lombardini ◽  
M. Pirro ◽  
G. Vaudo ◽  
...  
Keyword(s):  
Blood Viscosity ◽  
Whole Blood ◽  
Prognostic Impact ◽  
Whole Blood Viscosity ◽  
Low Shear

Effect of a fatty meal on whole blood and plasma viscosity

1963 ◽  
Vol 18 (6) ◽  
pp. 1217-1220 ◽  
Author(s):  
S. Charm ◽  
W. McComis ◽  
C. Tejada ◽  
G. Kurland
Keyword(s):  
Blood Viscosity ◽  
Whole Blood ◽  
Plasma Lipids ◽  
Capillary Tube ◽  
Plasma Viscosity ◽  
Fatty Meal ◽  
Whole Blood Viscosity ◽  
Before And After ◽  
Theoretical Considerations ◽  
Low Shear

The viscosity of whole blood of 40 medical students measured with a Brookfield cone and plate viscometer showed no change before and after a fatty meal although the serum lipids increased. In separate experiments, no change was noted in plasma viscosity as determined by the capillary tube technique although plasma lipids increased. From theoretical considerations, it was suggested that methods of determining viscosity within a 2% error would be necessary in order to detect changes in plasma and whole blood viscosity after a fatty meal. However, even with the GDM low-shear rate coaxial viscometer, which has an accuracy reputed to be 2%, no change was observed in the whole blood or plasma viscosity. The results with the GDM viscometer compared favorably with the results from the Brookfield cone and plate viscometer. In 2 out of 52 cases a definite decrease in whole blood viscosity was found 3 hr after a fatty meal. The plasma viscosities, however, did not change. It is postulated that in rare cases a decrease in the yield stress of the cell aggregates due to the increased lipids results in a decreased blood viscosity. The mechanics by which this occurred is under study. dietary fat; viscosity of blood Submitted on June 15, 1963

Whole blood viscosity predicts nondipping circadian pattern in essential hypertension

2020 ◽  
Vol 14 (14) ◽  
pp. 1307-1316
Author(s):  
Abdullah K Dolu ◽  
Ahmet Korkmaz ◽  
Harun Kundi ◽  
Umit Guray
Keyword(s):  
Essential Hypertension ◽  
Shear Rate ◽  
Blood Viscosity ◽  
Whole Blood ◽  
Blood Pressure Monitoring ◽  
High Shear Rate ◽  
High Shear ◽  
Whole Blood Viscosity ◽  
Protein Levels ◽  
Low Shear

Aim: We aimed to investigate the association between whole blood viscosity (WBV) and nondipping pattern in patients with essential hypertension. Materials & methods: A total of consecutive 530 patients who had been evaluated by ambulatory blood pressure monitoring were included. WBV was estimated by using hematocrit and plasma total protein levels for both WBV in low shear rate (0.5 s-1) and WBV in high shear rate (208 s-1) according to the de Simone’s formula. Results: In the multivariate analysis, low shear rate and high shear rate of WBV were associated independently with nondipping pattern in patients with essential hypertension. Conclusion: As a simple, inexpensive and noninvasive tool, WBV seems to be a significant predictor of nondipping hypertension.

scholarly journals Increased Whole Blood Viscosity Is Associated with the Presence of Digital Ulcers in Systemic Sclerosis: Results from a Cross-Sectional Pilot Study

2017 ◽  
Vol 2017 ◽  
pp. 1-5 ◽  
Author(s):  
Peter Korsten ◽  
Timothy B. Niewold ◽  
Michael Zeisberg ◽  
Tammy O. Utset ◽  
Daniel Cho ◽  
...  
Keyword(s):  
Systemic Sclerosis ◽  
Blood Viscosity ◽  
Whole Blood ◽  
Control Group ◽  
Capillary Viscometer ◽  
Convenience Sample ◽  
Rheumatology Clinic ◽  
Whole Blood Viscosity ◽  
Shear Rates ◽  
History Of

Objective. To investigate the role of whole blood viscosity in digital ulcer (DU) development in patients with diffuse and limited Systemic sclerosis.Methods. A convenience sample of patients with Systemic sclerosis (SSc) was selected from the adult Rheumatology clinic at the University of Chicago. The study group consisted of patients with SSc (with ulcers present, a history of ulcers, and no ulcers); the control group consisted of matched healthy Rheumatology clinic staff. WBV was measured using a scanning capillary viscometer at different shear rates (1–1000 1/s).Results. Whole blood viscosity as measured by a scanning capillary viscometer was increased in patients with SSc compared to healthy controls (p<0.0001). Additionally, patients with present DU had significantly higher whole blood viscosity when compared to patients with a history of DU and patients with no history of DU (p<0.0001). These findings were most pronounced at lower shear rates between 1 and 10 1/s.Conclusion. Whole blood viscosity might be a contributing factor in DU development in patients with SSc. Further studies with larger patient cohorts are required to fully evaluate how increased WBV contributes to the development of DU and whether the currently available treatment options improve the microcirculation by influencing WBV.

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