Inter-species differences in hematocrit to blood viscosity ratio

Németh, Norbert; Alexy, Tamás; Furka, Andrea; Başkurt, Oğuz K.; Meiselman, Herbert J.; Furka, I.; Miko, Iren

doi:10.3233/bir-2009-0533

Cited by 32 publications

(15 citation statements)

References 19 publications

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“…1,[15][16][17][18][19][20] The optimum hematocrit values for tube diameters of 500, 100, and 50 mm were 38%, 44%, and 51%, respectively. 17 In this study, we first performed analysis of the dynamic relationship between hematocrit and apparent suspension viscosity using a Couette-type viscometer 37,38 for RBCs suspended either in plasma (which induces RBC aggregation) or in saline (which does not have that effect). Using the viscometric data, we observed that increasing hematocrits increased RBC suspension viscosities exponentially and that suspension viscosities were inversely related to applied shear rates ( Fig.…”

Section: Discussionmentioning

confidence: 99%

Optimal hematocrit in an artificial microvascular network

et al. 2017

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BACKGROUND Higher hematocrit increases oxygen carrying capacity of blood, but also increases blood viscosity, thus decreasing blood flow through the microvasculature and reducing the oxygen delivery to tissues. Therefore, an optimal value of hematocrit that maximizes tissue oxygenation must exist. STUDY DESIGN AND METHODS We used viscometry and an artificial microvascular network (AMVN) device to determine optimal hematocrit in vitro. Suspensions of fresh red blood cells (RBCs) in plasma, normal saline or a protein-containing buffer, and suspensions of stored RBCs (at week 6 of standard hypothermic storage) in plasma with hematocrits ranging 10 – 80% were evaluated. RESULTS For viscometry, optimal hematocrits were 10, 25.2, 31.9, 37.1 and 37.5% for fresh RBCs in plasma at shear rates of ≤3.2, 11.0, 27.7, 69.5, and 128.5 s−1. For the AMVN, optimal hematocrits were 51.1, 55.6, 59.2, 60.9, 62.3 and 64.6% for fresh RBCs in plasma and 46.4, 48.1, 54.8, 61.4, 65.7 and 66.5% for stored RBCs in plasma at pressures of 2.5, 5, 10, 20, 40 and 60 cmH2O. CONCLUSION Although exact values of optimal hematocrit may depend on specific microvascular architecture, our results suggest that optimal hematocrit for oxygen delivery in the microvasculature depends on perfusion pressure. Anemia in chronic disorders may, therefore, represent a beneficial physiological response to reduced perfusion pressure resulting from decreased heart function and/or vascular stenosis. Our results may help explain why therapeutically increasing hematocrit in such conditions with RBC transfusion frequently leads to worse clinical outcomes.

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Section: Discussionmentioning

confidence: 99%

Optimal hematocrit in an artificial microvascular network

et al. 2017

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“…Free radicals generated due to artemether increase haemolysis, resulting in a decrease of the haematocrit 11 . The haematocrit is the major determinant of whole blood viscosity 15 . It is, therefore, likely that in the present study, artemether/lumefantrine generated the free radicals that caused increased haemolysis resulting in reduced hematocrit and ultimately reduced whole blood viscosity and elasticity.…”

Section: Resultsmentioning

confidence: 99%

In vitro effects of co-incubation of blood with artemether/lumefantrine & vitamin C on the viscosity & elasticity of blood

McKoy

Kong-Quee

Pepple

2016

Indian Journal of Medical Research

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Background & objectives:The antimalarial combination drug artemether/lumefantrine has been shown to be effective against malaria parasite through its haemolytic action. This drug is sometimes co-administered with vitamin C in patients with malaria. Vitamin C is associated with antioxidant properties which would be expected to protect against haemolytic effects of this antimalarial drug. This study was designed to investigate in vitro effects of co-incubation of artemether/lumefantrine with vitamin C on the viscosity and elasticity of blood.Methods:Blood was collected from 12 healthy female volunteers with normal haemoglobin genotype (HbAA). A Bioprofiler was used to measure the viscosity and elasticity of untreated blood samples (control) and samples exposed to artemether/lumefantrine (0.06/0.36 mg/ml) alone and with low or high dose vitamin C (equivalent to adult doses of 100 or 500 mg).Results:Artemether/lumefantrine significantly (P<0.05) reduced viscosity of blood from 4.72 ± 0.38 to 3.78 ± 0.17 mPa.s. Addition of vitamin C (500 mg) further reduced blood viscosity to 2.67 ± 0.05 mPa.s. The elasticity of blood was significantly (P<0.05) reduced from 0.33 ± 0.04 mPa.s to 0.24 ± 0.03 mPa.s by the antimalarial drug, and further reduced to 0.13 ± 0.02 mPa.s in the presence of vitamin C (500 mg).Interpretation & conclusions:Co-incubation of blood with vitamin C and antimalarial combination drug potentiates the haemolytic effects of the latter on reducing blood viscosity and elasticity in vitro. This may possibly have implications in relation to haemolysis in patients receiving vitamin C supplementation with artemether/lumefantrine during malaria therapy.

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“…This result indicates that blood viscosity is likely to be more affected by blood cell particle numbers than by blood cell volume. Although this comparison has not been addressed in human clinical studies, a previous animal study demonstrated that the blood cell count had a stronger influence on blood viscosity than the hematocrit [57]. This study also performed a comparison of hematological and rheological parameters between rats and dogs.…”

Section: Blood Viscosity Measurementmentioning

confidence: 98%

A Review on Rheology of Non-Newtonian Properties of Blood

Fatahian

Kordani

Fatahian

2018

IIUMEJ

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Human blood is composed of red cells, white blood cells, and platelets in a fluid called plasma that contains organic and mineral salts and protein. The rheological characteristics of blood are determined by the properties of these combinations and their interaction with each other. The plasma is essentially a Newtonian fluid, but the blood as a whole behaves as a non-Newtonian fluid showing all signs of non-Newtonian rheology including deformation rate dependency, viscoelasticity, yield stress, and thixotropy. The purpose of this study is mainly a review based on past work on blood rheology, determinants of blood viscosity, yield stress, thixotropy, blood viscosity measurement, and heat transfer in blood flow to better understand the non-Newtonian effect in the blood circulation system. ABSTRAK: Darah manusia terdiri daripada sel-sel merah, sel darah putih dan platlet dalam cecair yang dipanggil plasma, mengandungi garam organik dan mineral dan protein. Ciri-ciri sifat reologi darah ditentukan oleh sifat-sifat kombinasi ini dan interaksi antara satu sama lain. Plasma adalah pada dasarnya Newtonian cecair tetapi secara keseluruhannya darah bersifat sebagai bukan suatu cecair Newtonian yang menunjukkan tanda-tanda bukan Newtonian reologi, mengandungi pergantungan kadar ubah bentuk, kelikatkenyalan, tegasan alah dan thixotropi. Tujuan kajian ini adalah berkenaan ulasan kajian-kajian lepas berkaitan rheology darah, penentu viskositi darah, tegasan alah dan thixotropi, ukuran kelikatan darah dan pemindahan haba dalam aliran darah bagi memahami kesan bukan Newtonian dalam sistem peredaran darah.

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Inter-species differences in hematocrit to blood viscosity ratio

Cited by 32 publications

References 19 publications

Optimal hematocrit in an artificial microvascular network

Optimal hematocrit in an artificial microvascular network

In vitro effects of co-incubation of blood with artemether/lumefantrine & vitamin C on the viscosity & elasticity of blood

A Review on Rheology of Non-Newtonian Properties of Blood

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