Blood Viscosity Values Research Articles

F189. Variations of intraerythrocytic calcium and blood viscosity values in patients suffering from hemorrhagic and ischemic stroke treated with nimodipine

F189. Variations of intraerythrocytic calcium and blood viscosity values in patients suffering from hemorrhagic and ischemic stroke treated with nimodipine

Predicting factors of blood viscosity and red cell aggregation values in medical practice

Predicting factors of blood viscosity and red cell aggregation values in medical practice

Hemorheological changes in congestive cardiac failure

The primary cardiac defect in Congestive Cardiac Failure(CCF) is decrease in intrinsic contractility of myocardium, usually brought on by prolonged pressureandl or volume overload. A wide range of factors may precipitate or aggravate or worsen blood flow conditions leading to the cardiac failure, and hemorheological factors could be one of them. This investigation aimed to study the possible role and association between change in hemorheological parameters and congestive cardiac failure. Parameters studied in this study on 88 patients of congestive cardiac faliure were - whole blood viscosity, plasma viscosity, red cell rigidity, hematocrit, erythrocyte sedimentation rate, fibrinogen, cholesterol, triglycerides and albumin. The patients were categorized in to 2 subgroups on the basis of their clinical history and diagnosis. The first group was, congestive cardiac failure with coronary heart disease and second group congestive cardiac failure with hypertension. There were significant changes in the hemorheological parameters in both the groups. In cases of congestive cardiac failure with coronary heart disease rise in blood viscosity at low shear rate(p<O.OOOl) was more significant as compared to high shear rate(p<O.OI). Increases in plasma viscosity, red cell rigidity, fibrinogen and erythrocyte sedimentation rate were very significant. Among biochemical parameters increase in plasma triglycerides was statistically significant(p<O.Ol). In the second group, congestive cardiac failure with hypertension, showed marked increase in whole blood viscosity at low and high shear rates. In this group increase in red cell rigidity was most significant as(p<O.OOOl) compared to other parameters. Increase in plasma viscosity, fibrino­ gen and plasma cholesterol & triglycerides were also significant. It was found that the regular smokers had higher values of blood viscosity, red cell rigidity(p<O.05), hematocrit(p<O.005) and plasma viscosity(p<O.05) as compared to non-smoker patients in both the groups. There was no significant change in albumin and hematocrit in both the groups as compared to normal controls. The present study highlights the possible role of hemorheological factors along with other physiological factors in congestive cardiac failure.

Blood viscosity values and biochemical correlates in healthy adults

Blood viscosity values and biochemical correlates in healthy adults

Low values of blood viscosity and erythrocyte aggregation are associated with lower increases in blood lactate during submaximal exercise

(Received 13.7.1993; accepted 23.8.1993) Trained sportsmen have low values of blood viscosity (TJb). In this study we tested the functional consequences of this reduction of TJb in 34 sportsmen submitted to a 25 min progressively increasing submaximal work load. A low resting TJb (measured at high shear rate with the MT90 viscometer) was associated to a lower increase in blood lactate during exercise (correlation of llb with: maximal lactate value: r==0.357 p 2.4 mPa.s (with this method) had higher lactate increase (p<0.01) and a deeper decrease in blood bicarbonate (p<0.001). RBC rigidity ('Tk' index) is increased proportionaly to lactate when lactate increases above 4 mmol.l-1. Another group of 21 professional footballers was studied during a maximal triangular work load until V02 max. In this group there was a correlation between maximal lactate response during the test and RBC aggregation (r=0.705 p<0.005). These results suggest that low whole blood viscosity at rest either (a) prevents from excessive lactate increase in this kind of exercise protocol; (b) or is a marker of trained persons characterized by metabolic/circulatory adaptations protecting against exercise-induced hyperlactatemia. In these experimental conditions lower RBC aggregation (within the normal range) seems to be also associated with fitness and lower lactate increase.

Effect of fibrin(ogen) degradation products on blood viscosity values during thrombolysis

Effect of fibrin(ogen) degradation products on blood viscosity values during thrombolysis

Whole blood and plasma viscosity values in normal and ascitic broiler chickens.

1. Whole blood and plasma viscosity values in normal and ascitic broiler chickens were measured. 2. The mean blood viscosity value in ascitic broilers was greater than that of the controls. There was a small but significant difference in the opposite direction between plasma viscosity values of the respective groups of birds. 3. Although the haematocrit and arterial pressure index values in the ascitic birds were raised, there was a fall in the concentration of total plasma protein. 4. The data suggest that the raised viscosity in the ascitic birds was caused by a polycythemia and not by any influence of plasma protein. 5. The cumulative effect of these factors, such as raised blood viscosity values and larger deformed red cells flowing through constricted lung arterioles, may contribute to the pulmonary hypertension and ascites seen in some young commercial broilers.

Cord whole blood hyperviscosity: Measurement, definition, incidence and clinical features

Cord whole blood viscosity and haematocrit values (PCV) were determined in 2461 live birth infants. Viscosity measurements were performed on an Australian-designed coaxial narrow-gap viscometer. Normal viscosity values were determined for each week of gestation above 34 weeks. Hyperviscosity was defined as a viscosity value above 2 s.d. from the mean for each week of gestation and it occurred in 164 (6.7%) newborn infants. Although a close relationship existed between cord whole blood viscosity and PCV (r = 0.6597, P less than 0.0001), only 47.4% of polycythaemic infants (PCV greater than 65) were also hyperviscous and only 23.9% of hyperviscous infants were also polycythaemic. Hence, using the haematocrit to select which infants require viscosity studies fails to detect many hyperviscous newborn infants. Hyperviscosity was less common (3.6%, P less than 0.001) in infants who were born by Caesarean section and more common (16.5%, P less than 0.001) in those who were growth retarded. Of the hyperviscous infants, 84.5% were not growth retarded, most (87.8%) were term and most (86.6%) were delivered vaginally. Most hyperviscous newborn infants may thus remain undetected unless routine whole blood viscosity studies are performed.

Postoperative Changes in Blood Viscosity and the lnfluence of Hematocrıt

The blood viscosity and hematocrit values were determined in ten patients who had major surgical operations on preoperative anda first, third and sixth postoperative days. While blood viscosity was found to be significantly increased on postoperative first and third days than preoperative values, the hematocrit levels were significantly higher only on postoperative first day. The blood viscosity values at hematocrit values adjusted to 50% were also found to be significantly higher on postoperative first and third days.

ＰＧＩ２誘導体（ＴＲＫ‐１００）の生体内レオロジーに対する影響

Effect of PGI2 analogue (TRK-100) on haemorheological factors in patients with peripheral vascular disease.The effect of prostaglandin I2 analogue (TRK-100) on haemorheological factors (red cell deformability, whole blood viscosity, plasma viscosity, and plasma c-AMP) in 12 patients with peripheral vascular disease (Buerger's disease, arteriosclerosis obliterans and Raynaud's syndrome) were studied.Although red cell deformability was reduced in patients with peripheral vascular disease, TRK-100 (120μg/day, 6 weeks) was shown to be effective in improving the reduced red cell deformability.However, there was no statistical change in the values of whole blood viscosity, plasma viscosity or plasma c-AMP in this study.

Long-term effects of ticlopidine on fibrinogen and haemorheology in patients with peripheral arterial disease

The effects of ticlopidine treatment (250 mg b.i.d. for 21 months) on fibrinogen and other rheological variables, as compared to placebo, were studied in 44 patients with intermittent claudication due to peripheral arterial occlusive disease. Blood samples were collected every 3 months during this double-blind, randomised placebo-controlled trial which lasted 21 months. Consistently lower values of fibrinogen, haematocrit and whole blood viscosity at high and low shear rate levels were found in the ticlopidine group; the intergroup differences were statistically significant at most but not all follow-up examinations. A significant time-related variance was observed in the ticlopidine group for the measured variables, also after correction for the variability found in the placebo group. Thus, the observed changes in the ticlopidine group are mainly treatment related. These effects on fibrinogen and haemorheology may contribute, besides the known antiplatelet activity of the drug, to the clinical improvement reported in a larger group of claudicants to which the present subset of patients belong.

The Effect of Hemodialysis on Whole Blood, Plasma and Erythrocyte Viscosity

The effect of hemodialysis (HD) on blood viscosity has not been adequately investigated. We studied blood viscosity during HD employing coneplate viscometry. Ten patients with end-stage renal disease were studied before and immediately after HD. To dissect the possible effects of HD on plasma and red blood cell (RBC) determinants, we measured whole blood, plasma, and reconstituted erythrocyte viscosities. The latter consisted of RBC's suspended in a buffered saline solution (pH = 7.4 units). In addition, serum, electrolytes and hematocrit (HCT) were measured. The results revealed a significant rise in whole blood viscosity after dialysis. Likewise, plasma viscosity rose considerably with dialysis. However, when the RBC's were reconstituted to a constant HCT, no significant difference was noted before and after HD. As expected, body weight, blood urea nitrogen (BUN) and creatinine concentrations fell while HCT and protein concentration rose with HD. A significant correlation was found between the observed rise in HCT, and dialysis-induced rise in whole blood viscosity. Likewise, the observed rises in plasma viscosity after dialysis significantly correlated with the rise in protein concentration. In addition, the change in whole blood and plasma viscosity values correlated with the degree of ultrafiltration (weight loss). In conclusion, whole blood and plasma viscosity rises with hemodialysis. The observed rise in viscosity is primarily due to hemoconcentration.

Influence of cyclandelate on in vitro red blood cell deformability.

Using filtration and viscosity techniques, cyclandelate, some of its metabolites and flunarizine were evaluated to determine their ability to maintain human red blood cell (RBC) deformability. In filtration studies, RBC suspensions were metabolically depleted, which decreased the capacity of the cells to pass through narrow filter pores. In viscosity measurements performed with whole blood, metabolic depletion resulted in an increase of blood viscosity values. The results of these experiments appeared to indicate that cyclandelate, cyclandelate alcohol and flunarizine were approximately equipotent in maintaining RBC filtration and blood viscosity values. Cyclandelate acid appeared to be less active in both studies. By measuring the adenosine triphosphate content of red blood cells it has been shown that this activity is not due to an action on red blood cell energy metabolism. Finally, experiments conducted with the calcium chelator EGTA showed that the activity of cyclandelate was reduced in the absence of Ca++ ions. The results strengthen the hypothesis that cyclandelate maintains red cell deformability by inhibiting calcium entry through the red cell membrane.

Correlation between umbilical vein blood flow and umbilical blood viscosity in normal and complicated pregnancies

Umbilical vein blood flow (UVBF) was studied during the last 24 h before delivery using a combination of real-time and Doppler ultrasonic equipment in 64 normal and pathological pregnancies and the results were correlated with the values of whole blood viscosity taken from the umbilical vein after delivery. UVBF was reduced in the subgroup with chronic fetal distress (n = 14) (P less than 0.001) and the hypertensive pregnancies (n = 17) (P less than 0.05), whereas umbilical blood viscosity was increased only in the subgroup with chronic fetal distress (P less than 0.01) as compared with the normal pregnancies (n = 24). A significant positive correlation was observed between the umbilical blood viscosity and haematocrit values in all the groups of patients. UVBF and blood viscosity had a significant negative correlation in chronic fetal distress (P less than 0.001) and in hypertensive pregnancies (P less than 0.05), but not in normal or diabetic pregnancies (n = 9). Thus haemoconcentration leading to increased fetal blood viscosity may act as an aetiological factor in the reduction of UVBF in developing fetal distress.

Blood and plasma viscosity measurements in patients with glaucoma.

Blood viscosity at 10 shear rates, plasma viscosity, packed cell volume, plasma fibrinogen, serum alpha 2-macroglobulin, and serum proteins were measured in 83 patients with low-tension glaucoma (LTG) and 23 patients with 'high-tension glaucoma' (HTG: at least one IOP reading above 40 mmHg) and compared with those in 50 controls. Blood and plasma viscosity values and packed cell volume were significantly higher in the LTG group than those in controls. The HTG and the LTG groups differed only in plasma viscosity, but smoking and drinking habits in the HTG patients were greatly different from those in LTG patients and controls, thus preventing interpretation of data in the HTG group. Within the LTG group viscosity values were highest in a subgroup designated earlier by us as focal ischaemic LTG, whereas another subgroup, senile sclerotic LTG, did not show significant differences compared with controls. These findings may indicate a factor in the pathogenesis of visual field defects and disc cupping in some patients with LTG.

Anticoagulation therapy for renal insufficiency after burns

The changes in blood coagulation, fibrinolysis and kidney function and the effect of anticoagulation therapy using herapin were investigated in rabbits with full thickness skin loss burns covering 35 per cent of the total body surface area. Determinations of various kidney function tests, blood coagulation and fibrinolysis tests, blood viscosity and haematocrit values were made before burning and after 8 and 24 h. Thirty rabbits were divided into a non-therapy group, an intravenous infusion group, a heparin group, an antithrombin III group and an antithrombin III plus heparin group and the results were compared. Oliguria and a disturbance of kidney function were noted 8 h after the burn in the non-therapy group. In the intravenous infusion group urine volume was well maintained although the early stage of non-oliguric renal insufficiency was noted. The changes noted in the intravenous infusion group were prevented almost completely in the heparin group but FE Na and C H 2O were elevated at 24h probably because antithrombin III activity was markedly depressed. In the antithrombin III group and the antithrombin III plus heparin group, however, creatinine clearance (Cl cr) was moderately elevated while FE Na and C H 2O remained unchanged as compared with the values before the burn. The anti-thrombin III plus heparin group showed slightly better results than the antithrombin III group in U cr/P cr ratio, Cl cr and C H 2O . The results of the present study indicate that it is extremely effective to initiate appropriate fluid therapy immediately after a burn and to administer antithrombin III concentrate in combination with or without heparin for the prevention of acute renal insufficiency in patients with a severe burn.

Contributions of Red Cells and Plasma to Blood Viscosity in Preterm and Full-Term Infants and Adults

In preterm infants, plasma and red blood cells display several specific properties (eg, RBC size, plasma composition) that could influence blood flow behavior. Hemorheologic properties of blood from 20 preterm infants (24 to 36 weeks of gestation), ten full-term neonates, and ten adults were studied by means of a cone-plate viscometer adapted with a Couette-type chamber allowing viscometry at a wide range of shear rates (1.15 to 230/s). Blood viscosity (at given hematocrit of 60%), plasma viscosity, and RBC aggregation were very low in the smallest preterm infants, increased with gestational age, and reached the highest values in the adults. Whole blood viscosity increased directly with increasing plasma viscosity, plasma fibrinogen, and total plasma protein concentration, with the strongest correlations at the lowest shear rate of 1.15/s. The viscosity of RBCs suspended in a nonaggregating buffer solution was similar in all groups, thereby indicating that RBC deformability is similar in preterm infants, full-term neonates, and adults. Because mixing of neonatal and adult blood components occurs in most small preterm infants as a result of the transfusion of adult blood products, viscosities of cross suspensions (neonatal RBCs in adult plasma and adult RBCs in neonatal plasma) were measured. The exchange of neonatal plasma for adult plasma increased blood viscosity values in the neonates to adult values. On the other hand, the exchange of neonatal RBCs for adult RBCs did not affect blood viscosity. These results indicate that viscosity of blood with given hematocrit is lower in preterm infants than in term neonates and adults as a result of low plasma viscosity and low RBC aggregation, and that neonatal RBCs do not possess specific properties that influence blood viscosity.

Maternal and fetal blood viscosity throughout normal pregnancy

SummaryThe changing values of whole blood viscosity and its major determinants, haematocrit, plasma fibrinogen, total serum protein, plasma viscosity and erythrocyte deformability, were followed throughout and after normal pregnancy in a serial study of 50 patients.In a cross-sectional study of the same parameters in cord blood samples from 170 fetuses at varying gestations, the haemorheological profile of fetal blood was defined. The significance of these haemorheological measurements in the changing haemodynamics of pregnancy and as a background for the study of pathological pregnancy is discussed.

Studies of blood viscosity with a newly constructed rotational viscometer which operates via a desk top computer

Increasing interest is being shown in blood viscosity and the whole field of haemorheology. This study presents a newly constructed rotational Couette type viscometer which operates via a commercially available desk top computer and a digital plotter. The influence of haematocrit on blood viscosity is shown and the study also presents blood viscosity values of six to eight healthy men at 24 degrees C and 37 degrees C. At 37 degrees C values are shown both at natural haematocrit and at haematocrit 45%.

Blood viscosity in experimental acute renal failure.

We measured blood viscosity in rats 24 h after induction of acute renal failure by glycerol or HgCl2 injections. The blood viscosity values of rats with acute renal failure were significantly higher than those of controls at any shear rates. The mean values of plasma fibrinogen in animals with glycerol - (302.5 +/- 35.2 mg/100 ml) or HgCl2 - (342.1 +/- 15.9 mg/100 ml) induced acute renal failure were significantly elevated compared to control levels (169.6 +/- 16.7 mg/100 ml). We believe that the increased blood viscosity in acute renal failure was primarily due to high concentration of plasma fibrinogen. The elevated blood viscosity may affect capillary microvascular circulation of glomerular capillary beds.