Biomaterial Database

Effect of hematocrit on blood pressure via hyperviscosity. 1999

Y Cinar, and G Demir, and M Paç, and A B Cinar

Haydarpaşa Numune Hospital, Istanbul, Turkey. hnh@kilim.com.tr

Increase in blood viscosity, defined as resistance to flow, is one factor in hypertension and atherosclerosis that contributes to the morbidity and mortality associated with tissue ischemia. In this research we evaluated the effect of hematocrit on increasing viscosity, and possible related changes in blood pressure, flow rate, and the equivalent physiologic compensation ratios. Blood samples were taken from 32 healthy individuals and centrifuged for 5 min at 3000 rpm to obtain 2.5 mL of erythrocyte mass from each. Then, at each step 0.5 mL of plasma was consecutively added in a total of 17 steps. The resultant hematocrit and viscosity changes were measured. Viscosity measurement was performed by capillary viscometer. The results were evaluated by the Student t test. It was observed that in the range of 60.16% and 25.32%, a 10.99% increase of hematocrit produced an increase of 1 unit relative viscosity, which means approximately a 20% increase in blood viscosity for a healthy individual. According to Poiseuille's equation, with a constant vessel length, if viscosity is increased by 20%, the decrease in blood flow rate will be 16.67% (100/120 = 83.33%; 100 - 83.33 = 16.67%). For the physiologic compensation of 20% increased viscosity, blood pressure increase will be 20% or vasodilation will be 4.66% in radius. Atherosclerotic and some healthy vessels with little vasodilatory capacities might benefit from treatment modalities to decrease the viscosity by hemodilution.

UI	MeSH Term	Description	Entries
D006973	Hypertension	Persistently high systemic arterial BLOOD PRESSURE. Based on multiple readings (BLOOD PRESSURE DETERMINATION), hypertension is currently defined as when SYSTOLIC PRESSURE is consistently greater than 140 mm Hg or when DIASTOLIC PRESSURE is consistently 90 mm Hg or more.	Blood Pressure, High,Blood Pressures, High,High Blood Pressure,High Blood Pressures
D011086	Polycythemia	An increase in the total red cell mass of the blood. (Dorland, 27th ed)	Erythrocytosis,Erythrocytoses,Polycythemias
D011237	Predictive Value of Tests	In screening and diagnostic tests, the probability that a person with a positive test is a true positive (i.e., has the disease), is referred to as the predictive value of a positive test; whereas, the predictive value of a negative test is the probability that the person with a negative test does not have the disease. Predictive value is related to the sensitivity and specificity of the test.	Negative Predictive Value,Positive Predictive Value,Predictive Value Of Test,Predictive Values Of Tests,Negative Predictive Values,Positive Predictive Values,Predictive Value, Negative,Predictive Value, Positive
D012016	Reference Values	The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.	Normal Range,Normal Values,Reference Ranges,Normal Ranges,Normal Value,Range, Normal,Range, Reference,Ranges, Normal,Ranges, Reference,Reference Range,Reference Value,Value, Normal,Value, Reference,Values, Normal,Values, Reference
D001794	Blood Pressure	PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.	Systolic Pressure,Diastolic Pressure,Pulse Pressure,Pressure, Blood,Pressure, Diastolic,Pressure, Pulse,Pressure, Systolic,Pressures, Systolic
D001809	Blood Viscosity	The internal resistance of the BLOOD to shear forces. The in vitro measure of whole blood viscosity is of limited clinical utility because it bears little relationship to the actual viscosity within the circulation, but an increase in the viscosity of circulating blood can contribute to morbidity in patients suffering from disorders such as SICKLE CELL ANEMIA and POLYCYTHEMIA.	Blood Viscosities,Viscosities, Blood,Viscosity, Blood
D004906	Erythrocyte Count	The number of RED BLOOD CELLS per unit volume in a sample of venous BLOOD.	Blood Cell Count, Red,Erythrocyte Number,Red Blood Cell Count,Count, Erythrocyte,Counts, Erythrocyte,Erythrocyte Counts,Erythrocyte Numbers
D006400	Hematocrit	The volume of packed RED BLOOD CELLS in a blood specimen. The volume is measured by centrifugation in a tube with graduated markings, or with automated blood cell counters. It is an indicator of erythrocyte status in disease. For example, ANEMIA shows a low value; POLYCYTHEMIA, a high value.	Erythrocyte Volume, Packed,Packed Red-Cell Volume,Erythrocyte Volumes, Packed,Hematocrits,Packed Erythrocyte Volume,Packed Erythrocyte Volumes,Packed Red Cell Volume,Packed Red-Cell Volumes,Red-Cell Volume, Packed,Red-Cell Volumes, Packed,Volume, Packed Erythrocyte,Volume, Packed Red-Cell,Volumes, Packed Erythrocyte,Volumes, Packed Red-Cell
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D012307	Risk Factors	An aspect of personal behavior or lifestyle, environmental exposure, inborn or inherited characteristic, which, based on epidemiological evidence, is known to be associated with a health-related condition considered important to prevent.	Health Correlates,Risk Factor Scores,Risk Scores,Social Risk Factors,Population at Risk,Populations at Risk,Correlates, Health,Factor, Risk,Factor, Social Risk,Factors, Social Risk,Risk Factor,Risk Factor Score,Risk Factor, Social,Risk Factors, Social,Risk Score,Score, Risk,Score, Risk Factor,Social Risk Factor