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PubMed2003

Influence of propofol on erythrocyte morphology, blood viscosity and platelet function.

The intravenous anaesthetic propofol has been associated with cardiovascular side effects. We therefore studied its influence on blood viscosity, erythrocytes and platelet aggregation. Blood from healthy volunteers was incubated with propofol concentrations of 0, 5, 10, 20, 40, 80, 200, and 500 microg/ml plasma. Whole blood viscosity (shear rates 94.5 and 0.1 s(-1)), plasma viscosity, erythrocyte morphology and platelet aggregation (PFA-100 system) were determined. These parameters were also measured in vivo in 9 patients prior to anaesthesia, after induction, before the end and 1 h after the end of propofol anaesthesia. Propofol induced a slight, dose-dependent echinocytic shape transformation of erythrocytes in vitro, indicating a preferential intercalation of the drug in the outer hemileaflet of the membrane. Neither whole blood nor plasma viscosity were affected in vitro. In vivo, no change in erythrocytes shape was seen, but plasma and whole blood viscosity at high shear rate (94.5 s(-1)) were decreased at the end of anaesthesia, which may be due to some extent to plasma dilution. Platelet aggregation with epinephrine was decreased both in vitro and in vivo. We conclude that propofol interacts with the erythrocyte membrane without affecting blood and plasma viscosity and decreases platelet aggregation, which may have clinical implications.

Adult↗

PubMed1992

[Plasma-erythrocyte viscosity and evaluation of several pro- and anti-aggregating factors in NIDDM patients in metabolic decompensation state].

In NIDDM diabetic subjects, the microcirculatory damage shows a double aspect: an alteration of the vascular wall, particularly of the arteriolar capillary, and a hemorheological alteration at the level of the capillary district. In the microcirculation, because of the low velocity of the flow and the inverse relationship between capillary size and RBC diameter, the viscosity has an important role with its components: RBC viscosity and deformability. Even the erythrocyte aggregation has a key role as resultant of the attracting and repulsing forces, among which the plasma-RBC viscosity and the deformability play opposite role. Our method allows to evaluate the erythrocyte, the whole blood, the plasma and the plasma-RBC viscosity, and the deformability. Studies from this laboratory in NIDDM subjects show an increase in the blood viscosity, a decrease in the erythrocyte deformability and plasma-RBC viscosity. It is suggested that in microcirculatory district the flow reductions are particularly of hemorheological type and that the sludged blood is an "optical" phenomenon with poor meaning. We consider some hematological parameters, namely the Hgb A1c %, Hgb concentration, RBC count, MCV, etcetera.

Aged↗

PubMed2004

Increased incidence of adverse perinatal outcome with low maternal blood viscosity in preeclampsia.

Hyperviscosity of the maternal blood has been reported to be associated with an increased incidence of adverse perinatal outcome in preeclampsia. We related the changes in maternal blood viscosity to perinatal outcome in 47 preeclamptic, nulliparous, black Jamaican women. A group of 49 non-preeclamptic, nulliparous, gestation-matched women acted as controls. Perinatal outcome was also compared between the women with high blood viscosity (> or = 5 mPa.s) and those with low blood viscosity (< 5 mPa.s) in both the preeclamptic and non-preeclamptic groups. Data was analysed by the comparison of two proportions, the chi-squared test, the Fisher's exact test and the Pearson's correlation method. The level of statistical significance was taken at p < 0.05. The incidence of adverse perinatal outcome was significantly (p < 0.001) higher in the preeclamptic women as compared with that of the non-preeclamptic controls. However, of interest, was the fact that within the preeclamptic group, the incidence of adverse perinatal outcome was significantly (p = 0.001, Fisher's exact test) higher in those with low blood viscosity as compared with those with high blood viscosity. These results suggest that low maternal blood viscosity may be related to increased incidence of adverse perinatal outcome in Jamaican women with preeclampsia.

Adolescent↗

PubMedDate not supplied

The effect of aerobic exercise on blood and plasma viscosity on cardiac health club participants.

AIM: to analyze the effect of SJS aerobic exercise on blood and plasma viscosity. METHODS: the study was performed on 30 subjects with an age span of 40 to 60 years. Subjects participated in SJS aerobic exercise of moderate intensity of 40 to 45 minutes duration, three times a week for 9 to 12 weeks. Five milliliters of blood were collected into K3EDTA container to assess blood and plasma viscosity prior to the program and following the completion of the SJS program. Blood and plasma viscosity was measured using Brookfield LVDV-III viscometer using rotational method principle. RESULTS: this study demonstrated a significant decrease in blood viscosity (2.94%, p = 0.03) and insignificant decrease in plasma viscosity in subjects following SJS aerobic exercise compared to prior exercise. CONCLUSION: this study proved that SJS aerobic exercise of moderate intensity of 40 to 45 minutes duration times a week for 9 to 12 weeks gave the benefit of lowering blood viscosity, which contributes to reducing the risk of coronary heart disease.

Adult↗

PubMedDate not supplied

Blood viscosity and filtration abnormalities in mixed cryoglobulinemia patients.

Blood, plasma and serum viscosity and blood filtration were investigated in 43 unselected mixed cryoglobulinemia patients. A hyperviscosity syndrome was present in only one patient, and rapidly improved after plasma exchange and cyclophosphamide therapy. A clear-cut increase in blood viscosity was infrequently observed in mixed cryoglobulinemia, although significant differences were present in the plasma and serum viscosity of patients and controls. In contrast, blood filtration was severely impaired in a high percentage of cases (51 and 72% of the values recorded at 37 degrees and 25 degrees C, respectively), and was on the average significantly higher in patients than in controls. Indirect evidence suggests that blood viscosity is at least in part related to cryoglobulins. In 19 patients studied before and after cryoglobulin removal, serum viscosity significantly decreased when the serum was deprived of cryoglobulins. In addition, the cryocrit correlated with all the hemorheological parameters with the exception of blood filtration. The hemorheological findings were compared with multisystemic features of the disease, i.e. liver, renal, lung, neurologic, vascular and funduscopic alterations. The potential clinical relevance of the hemorheological parameters was stressed by the close correlation between blood filtration parameters and serum creatinine. Furthermore, by discriminant analysis, viscosity and blood filtration changes were the serological parameters most significantly associated with the presence of renal, liver and neurological involvement. Thus, hemorheological parameters are frequently abnormal in mixed cryoglobulinemia patients, and seem to play a significant clinical role; they should therefore be included in the work-up of these patients.

Adult↗

PubMed1989

Studies on blood viscosity during the menstrual cycle and in the postmenopausal period in healthy women.

Blood viscosity was measured in 14 healthy, menstruating women, aged 17-51 years and in 10 healthy, postmenopausal women, aged 55-64 years. The fertile women were studied once a week during a normal menstrual cycle and the postmenopausal women twice with an interval of 2 weeks. Blood viscosity was measured at natural hematocrit as well as at hematocrit 45%. In the postmenopausal women no changes in blood viscosity were found. In the fertile women, blood viscosity at hematocrit 45% was lowest at the start of the menstrual bleeding and increased to a peak at day 7 (p less than 0.01), with a similar pattern when measured at natural hematocrit. Plasma viscosity also had its lowest value at the onset of menstrual bleeding, increasing to a maximum at day 21. Changes in plasma triglycerides, but not in fibrinogen or cholesterol, seemed to contribute to this increase. Plasma factors only partly explained the variations in blood viscosity, and changes in red cell properties were also found to be of importance. The clinical significance of these rheological changes remains to be established, but at least theoretically there may be an increased risk for thromboembolism, e.g. at surgery, during days 5-15 of the cycle. In studies on blood flow and rheological conditions in fertile women, it seems advisable to standardize for time in the menstrual cycle.

Adult↗

PubMed1989

Viscosity of human salivary mucins: effect of pH and ionic strength and role of sialic acid.

The viscosity of isolated human salivary mucins has been studied as a function of shear rate, mucin concentration, pH, and ionic strength. At neutral pH, viscosity increased proportionally with mucin concentrations between 0 and 14 mg/ml. Increasing the ionic strength from 35 to 235 mM resulted in an approximately 50% decrease in specific viscosity. A part from the ionic strength effect, no specific effect of calcium ions was observed. Under low ionic strength conditions, viscosity of mucin solutions reached a maximum value at pH 4.2. The extent of the viscosity increase was dependent on ionic strength, mucin concentration and shear rate. Increase of the ionic strength up to 200 mM almost completely abolished the pH-optimum, suggesting that electrostatic interactions underlie the pH-dependent behaviour. The position of the pH-optimum was not changed upon desialization of the mucin, indicating that terminal sialic acid residues do not determine the pH-dependence of human salivary mucin viscosity.

Humans↗

PubMed1989

Changes in blood viscosity following nifedipine administration and its relation to the contents of adenosine triphosphate and 2,3-diphosphoglyceric acid in red blood cells in patients with angina pectoris.

The effect of oral administration of nifedipine (Adalat) on whole blood viscosity in patients with angina pectoris was investigated. Whole blood viscosity at a low shear rate of 37.5 s-1 was significantly reduced from 7.90 +/- 0.18 cP to 7.30 +/- 0.27 cP (1 cP = 1 mPa x s) after nifedipine administration (p less than 0.01), though the value at the high shear rate of 375 s-1, Casson yield stress value and Casson viscosity hardly decreased. Content of adenosine triphosphate (ATP) and 2,3-diphosphoglyceric acid (2,3-DPG) in the erythrocytes affecting blood viscosity, especially low shear rate viscosity, showed little change, and the hematocrit value was little varied either. Nifedipine, a Ca antagonist, has been known to inhibit Ca entry into the cells. These findings suggest that nifedipine reduces whole blood viscosity, especially low shear rate value, due to inhibition of Ca entry into the red blood cells, without increasing metabolic changes of ATP or 2,3-DPG in the erythrocytes, though measurement of Ca content in erythrocyte was unsolved.

2,3-Diphosphoglycerate↗

PubMed1987

[Blood, plasma, erythrocyte viscosity and index of erythrocyte filtration in subjects with hyperlipemia].

40 hyperlipidaemic patients (26 type II a and b, 14 type IV) and 50 healthy controls were studied. The patients were not suffering from any other pathology of note and were under no drug treatment. Blood viscosity at natural Ht and at Ht 45% and plasma viscosity were measured. Red blood cell viscosity and deformability was studied on washed red cells, poor in leucocytes and platelets and suspended in a saline phosphate buffer. The patients with hyperlipidaemia had blood viscosity higher than healthy people. Red blood cell and plasma viscosity were higher in subjects with hyperlipidaemia. There was no difference in the filtration index between the people under study. The increased blood viscosity found in people with hyperlipidaemia appears to be attributable to changes in both the plasma and the erythrocytes.

Adult↗

PubMed1986

Umbilical cord whole blood viscosity and the umbilical artery flow velocity time waveforms: a correlation.

The possibility was examined of an association between umbilical cord whole blood viscosity and umbilical artery flow velocity time waveforms obtained with continuous wave Doppler ultrasound. The cord blood viscosity was measured at both high (100 s-1) and low (0.1 s-1) shear rates with a concentric cylinder viscometer. Plasma viscosity and fibrinogen were also measured. An abnormal pattern in the umbilical artery flow velocity waveform (high A/B ratio) indicative of high resistance was associated with an increase in whole blood viscosity at high shear (which may reflect a change in red cell rigidity). Viscosity at low shear (reflecting red cell aggregation and rouleaux formation) did not differ. There was a significant association between the small-for-gestational age fetus and abnormal umbilical artery waveform study (P less than 0.002) but not abnormal whole blood viscosity at high (P = 0.09) or low (P = 0.08) shear.

Blood Flow Velocity↗

PubMed1987

Volume of a swallow: role of orifice size and viscosity.

Following approval by an Institutional Review Board and a pilot study with adults, children aged 24 months to 71 months were encouraged to drink from a 28 fl oz flexible, plastic bottle with either a small diameter orifice (7 mm) or large diameter orifice (28 mm). The bottles contained either a low viscosity, an intermediate viscosity, or a higher viscosity liquid. Approximately 24 children evaluated each orifice/viscosity combination. The results, expressed as ml/swallow/kg body weight, showed that reducing orifice diameter reduced the volume of a swallow for the low viscosity liquid but did not appear to affect swallow volume for the intermediate or higher viscosity liquids. Additionally, swallow volume was found to be inversely related to viscosity of the test liquid.

Body Weight↗

PubMed1985

[Blood viscosity indicators in patients with gastric and duodenal diseases].

A total of 102 patients with peptic ulcer of the stomach and duodenum, chronic gastritis, and erosive gastritis were examined. A statistically significant increase in blood viscosity was recorded during the diseases enumerated. In peptic ulcer and chronic gastritis, the fibrinogen and hematocrit levels did not change quantitatively although quantitative changes in the fibrinogen level were likely to influence blood viscosity. Red cell aggregation was found to be increased, being the main factor responsible for blood viscosity deterioration. The authors studied the effect of cimetidine on blood viscosity in patients with peptic ulcer and the effect of peritol in chronic gastritis. These drugs were found to markedly reduce blood viscosity, as a result of which the circulation in the gastric mucosa improved, promoting the cure of patients with peptic ulcer. According to the authors' opinion, cimetidine, that blocks H2 histamine receptors, lessens the effect of histamine on red cell aggregation, thereby improving blood viscosity.

Adolescent↗

PubMed1985

[Blood viscosity: an original method for the study of low values of the shear rate].

A method for studying blood viscosity at low shear rates (from 4 x 10(-2) to 7 x 10(1) sec-1), i.e. in the shear range in which higher is the influence of shear rate on viscosity, was developed. Blood viscosity is expressed by the two regression coefficients of a power regression, according to the function: eta = a . Db where eta is viscosity. D is the shear rate, a and b are the two regression coefficients, which are independent of the shear rate. We found that the regression power was highly significant in a wide hematocrit range. Practically, this work deals with the possibility of application to the blood of the Ostwald formula for pseudoplastic flow behavior. We found significant correlations between the two regression coefficients and hematocrit and plasma viscosity, so correcting by calculation the two regression coefficients for standard hematocrit and standard plasma viscosity. This method is simple and can easily be automatically driven by a computer.

Blood Viscosity↗

PubMed1979

[The behavior of blood viscosity in polyglobulism].

In polyglobulic subjects we have found a variable reduction of plasmatic viscosity, with an increase of total viscosity. If the increase of Ht is the first cause of the increase of total viscosity, it is less simple to find the cause of plasmatic viscosity decrease; to this end we have analysed direct and indirect factors (coagulation factors, proteinous and lipidic components). We haven't found any significant qualitative alterations. It is proposed the importance of the interventions of basic proteins of polication type. To this end it has been studied the connection between plasmatic viscosity and ESR, being both influenced by the same factors, but in a contrary way and with variable results. Then the role of plasmatic viscosity in these subjects, in substitution of ESR, is significant.

Adult↗

PubMed1977

The relationship of plasma fibrinogen, erythrocyte flexibility and blood viscosity.

Measurements have been made of plasma fibrinogen concentration, erythrocyte flexibility and blood viscosity at shear rates from 5.75 to 230 sec-1 during and following surgery. In the post-operative period the plasma fibrinogen level in the patient rose to over 1,000 mg/dl and because there were subsequent complications, only returned to normal after 4 weeks. There was an associated change of erythrocyte flexibility, with a correlation coefficient of 0.98. The blood viscosity also varied with the plasma fibrinogen level, the effect being more pronounced at low shear rates. The internal viscosity of the red blood cell, calculated from the plasma viscosity and whole blood viscosity at 230 sec-1, decreases with increasing plasma fibrinogen concentration, in agreement with the direct measurements made of erythrocyte flexibility. It is proposed that at high shear rates an increase in plasma viscosity due to an elevation of fibrinogen concentration, is offset by a decrease in the rigidity of the erythrocytes, and these 2 effects counter-balance.

Blood Viscosity↗

PubMed1978

Viscosity of duodenal juice examined in patients with excretory pancreas insufficiency by the pancreocymin secretin test compared to a control group and patients with cholelithiasis.

The viscosity of duodenal juice obtained during the pancreocymin secretin test from patients with excretory pancreas insufficiency was significantly higher compared to the viscosity of duodenal secretions from a control group or from patients with gall bladder stones. Since the viscosity was inversely related to the total volume as well as the bicarbonate and trypsin concentrations, it is concluded that the increased viscosity is due to a reduction in the secretory activity of the pancreas. The viscosity measurements found for patients with cholelithiasis reflects merely the higher viscosity of the gall bladder bile.

Adult↗

PubMed1978

[The effect of operation, anaesthesia and blood viscosity on haemodynamic during aortofemoral bypass operation (author's transl)].

Cardiac index, total peripheral resistance, blood, plasma and serum viscosity in patients with peripheral vascular disease were measured pre-, intra- and postoperatively. Besides plasma and serum viscosity, most obviously blood viscosity decreased during anaesthesia and operation. The decrease of blood viscosity is caused mainly by the falling haematocrit. Red blood cell aggregation occuring under low-flow conditions is decreased. Thus blood viscosity additionally is diminished at least in the area of low shear rates. Corresponding haemodynamic measurements revealed that decreasing viscosity improves cardiac index and total pressure resistance if normovolaemia exists, but in general is masked by anaesthesia and operation.

Anesthesia↗

PubMed1984

Glomerular hyperfiltration and blood viscosity in type I (insulin-dependent) diabetic subjects.

To investigate whether the increased glomerular filtration rate (GFR) in short-term diabetic patients is related to increased blood- or plasma viscosities, GFR [( 51Cr] EDTA-clearance), whole blood- and plasma viscosities were simultaneously determined in 16 insulin-dependent diabetic subjects, aged 11 to 34 years (duration of disease 0.1 to 8 years) and compared to the results in healthy subjects. Mean standard GFR +/- SD (that is, GFR corrected to body surface area of 1.73 m2) was significantly higher in the diabetics than in 16 age- and sex matched controls (142 +/- 26 ml/min vs. 123 +/- 18 ml/min, P less than 0.02). Blood viscosities at different shear rates and the plasma viscosity were not significantly different in the two groupes , although the plasma fibrinogen level was significantly elevated in the diabetics (376 +/- 60 mg%, vs. 289 +/- 37 mg%, P less than 0.001). No correlation was found between GFR and the viscosity measurements. The results of the present study do not support the suggestion that the increased GFR in short-term diabetics is related to changes in blood viscosity.

Adolescent↗