whole blood viscosity

Whole blood viscosity refers to the resistance formed by friction when two parallel layers of fluid flow are displaced from each other when blood flows. Whole blood viscosity is a combination of serum viscosity, hematocrit, erythrocyte deformability and aggregation, platelet and leukocyte rheological properties. In addition, blood viscosity is also affected by blood physicochemical properties (such as temperature, pH, plasma osmotic pressure, etc.), vascular factors and the like. Blood viscosity is also related to blood flow perfusion, so the whole blood viscosity has two kinds of viscosity: high shear and low shear. The high shear viscosity reflects the deformability of red blood cells, low deformability, high blood viscosity, low shear viscosity reflects the ability of red blood cells to aggregate, red blood cells aggregate and blood viscosity increases. Basic Information Specialist classification: cardiovascular examination classification: blood examination Applicable gender: whether men and women apply fasting: fasting Tips: Eating will cause changes in hematocrit and plasma composition, so the blood collection time is appropriate for early morning fasting. Normal value Low shear viscosity male 7.51 ~ 10.09mPa · s. Female 5.84 ~ 8.05 mPa · s. The high shear viscosity of men is 5.63~6.67mPa·s. Female 4.74 ~ 5.86mPa · s. Capillary method: M (male): 4.25 (+-) 0.41 F (female): 3.65 (+-) 0.32. Rotation method: (37 ° C) M (male) F (female) unit 230 / S: 4.53 (+-) 0.464.22 (+-) 0.41 Pa · s115 / S: 9.31 (+-) 1.488.37 (+- ) 1.22mPa·s. Clinical significance Whole blood viscosity measurement can provide a reference for many clinical diseases, especially for the diagnosis and treatment of prethrombotic state and thrombotic diseases. Increased blood viscosity is seen in a) plasma protein abnormal macroglobulinemia, multiple myeloma, congenital hyperfibrinemia and the like. b) Increased number of red blood cells: primary or secondary polycythemia, pulmonary heart disease, leukemia, high altitude environment, long-term hypoxia, etc. c) Increased erythrocyte aggregation promotes myocardial infarction, coronary heart disease, cerebral infarction, diabetes, thromboangiitis obliterans, pulmonary infarction, retinal arteriovenous thrombosis, abnormal hemoglobinopathy, etc. d) Other hyperlipoproteinemia, Raynaud's syndrome, tumors, etc. Reduce anemia, hemorrhagic disease, cirrhosis, uremia, acute hepatitis, women's menstruation and pregnancy. Precautions (1) Blood collection and anticoagulation: Improper blood collection can cause viscosity measurement errors. According to the recommendations of ICSH, the compression time of the cuff should be as short as possible. After the needle is inserted, the blood should be collected after the pressure pulse is released for 5 s. When the blood is drawn, the force should not be too strong. The anticoagulant should use a solid anticoagulant to prevent dilution of the blood. If liquid anticoagulation is used, the concentration of the anticoagulant should be increased to reduce the amount of liquid added, usually with heparin or dipotassium edetate or Disodium (EDTA-K: or EDTA-Na2) is anticoagulated, but potassium salt is preferred because of its high solubility. (2) Storage time of sample: It should be tested immediately after blood collection. If stored at room temperature for too long, the measurement result will be too high. It is best to complete the test within 4 hours. If stored in a refrigerator at 4 ° C can be extended to 12 h, blood specimens should not be stored below 0 ° C, because red blood cells will rupture under freezing conditions. (3) Influence of life rhythm: Some studies have pointed out that the blood viscosity of the human body changes regularly in one day, with two peaks at 11 am and 8 pm. Eating can cause changes in hematocrit and plasma composition, so blood collection time is appropriate for early morning fasting. Inspection process (1) Capillary viscometer method: 1 The blood was taken from the subject intravenously, and the blood per hectare was anticoagulated with heparin 10-20 u or dipotassium edetate 1.5-2.2 mg. 2 Place the sample in a water bath, keep it at a constant temperature for 5 minutes, mix it, add it to the reservoir, and press the measurement button to start timing. 3 According to the operation of 2, the physiological saline flow time is measured. 4 Calculate the apparent viscosity of blood flow at each average shear rate according to (Formula 4) or (Formula 5). 5 Convolution is an important factor affecting viscosity. To facilitate the analysis of measurement results, hematocrit can be measured by micro-capillary method. (2) Rotary viscometer method: 1 Turn on the instrument to warm up and let the constant temperature system reach the test temperature. 2 After the sample is kept at the test temperature for 5 minutes, mix well and add to the sample cup. 3 Press the measurement button and the shear rate is measured in descending order. In order to avoid the sinking of blood cells, the choice of shear rate should not be too much, and the retention time should not be too long. 4 After each sample is measured, the sample cup should be cleaned and dried. Not suitable for the crowd Generally no taboos. Adverse reactions and risks Discomfort: There may be pain, swelling, tenderness, and visible subcutaneous ecchymosis at the puncture site.

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