Blood Viscosity Values Research Articles

Experimental Broad-Based Curved Sidewall Aneurysms in Rabbits Mimicking Human Carotid Siphon Aneurysms: Proof of Feasibility and Comparability Using Computational Fluid Dynamics

Broad-based sidewall aneurysms of the carotidartery are primarily treated endovascularly. However,recurrence or rupture after treatment still poses a significant risk. Hence, reliable animal models mimicking this aneurysm type are essential for to evaluate the performanceof new advanced endovascular devices. Experimental aneurysms were created in 12 New Zealand white rabbits (2.5-3.5 kg). The human carotid siphon was mimicked with an end-to-end anastomosis of both common carotid arteries. A venous pouch was sutured on the convexity to mimic a broad-based side wall aneurysm. Patency and configuration were investigated 4 weeks postoperatively by 3-T magnetic resonance angiography. To compare flow conditions of broad-based sidewall aneurysms in rabbits and humans, exemplary computational fluid dynamics simulations were performed using species-specific blood viscosity values. We were able to achieve 0% peri- or postoperative mortality. Patency was confirmed by 3-T magnetic resonance angiography in 11 of 12 aneurysms (91.7%). Aneurysm lengths ranged from 6.4 to 9.8 mm and aneurysm necks from 7.3 to 9.8 mm. Computational fluid dynamics showed simple flow profiles with one vortex in rabbit as well as in human aneurysms. Wall shear stress rates were comparable using species-specific blood viscosity values (rabbit mean 1.65 Pa vs. human mean 1.7 Pa). The broad-based curved sidewall aneurysm model mimicking the carotid siphon showed high aneurysm patency rates with low morbidity. High comparability with human flow patterns and human intranaeurysmal biomechanical forces was shown using simulations.

The Effect of Chronic Levetiracetam Use on Erythrocyte Deformability

ABSTRACT Background: The inhibition of carbonic anhydrase (CA) isoenzymes is one of the targets in the development of new antiepileptics. Levetiracetam (LEV) is a new-generation antiepileptic drug frequently used in pediatric patients. It has a strong inhibitory effect on CA enzymes in many tissues, including erythrocytes. Objective: Due to CA enzymes have physical connection with the erythrocyte membrane and cytoskeleton, we aimed to evaluate the probable effect of LEV on the erythrocyte deformability. Materials and Methods: This study was conducted in the Experimental Animal Laboratory of Ankara Training and Research Hospital 24 prepubertal female Wistar albino rats were divided into four groups with six animals in each group. Group I: Control (distilled water), Group II: LEV50 (50 mg/kg/day), Group III: LEV150 (150 mg/kg/day), Group IV: LEV300 (300 mg/kg/day). The calculated dose for each animal was given by oral gavage once a day for 14 days, which is accepted as chronic use in experimental models. At the end of the treatment period, erythrocyte deformability was evaluated both with whole blood viscosity at high shear rates, and osmotic fragility test. Results: No statistically significant difference was found between the groups in terms of osmotic fragility. Whole blood and plasma viscosity values also did not show any statistically significant difference between the groups. Conclusion: In this study, it has been shown that LEV does not have a negative effect on erythrocyte deformability. Therefore, we thought that it may be a good choice when an antiepileptic is needed in pediatric patients with hematological disorders.

Abstract WP156: Temporal Changes in Blood Viscosity in Acute Ischemic Stroke and Its Relationship With Infarct Growth and Hemorrhagic Transformation

Background: Blood viscosity (BV) affects blood vessel wall shear stress. Yet, temporal changes of BV in acute stroke patients and correlation with infarct growth and hemorrhagic transformation remain unclear. Method: This prospective observational study included acute ischemic stroke patients admitted within 24h of the last known well time, who gave an informed consent and had adequate blood sampling. Consecutive BV measurements (at 10Hz) were taken upon admission (1 st ), at 24h (2 nd ), and between 5-7 days post-admission. Each patient underwent initial and follow-up MRI. Outcomes were 1) infarct growth or recurrence, and 2) increased hemorrhagic transformation (HT) in follow-up MRI compared to the initial MRI. We assessed whether the ratio of the 2nd BV to the 1st BV and 3 rd BV to the 1 st BV were associated with outcomes. Results: Twenty-six patients met eligible criteria and had adequate blood sampling. BV demonstrated a decreasing trend during the admission (1 st BV: median 20.2 [IQR 14.8-23.2], 2 nd BV: 17.9 [14.8-20.2], 3 rd BV: 15.3 [12.0-22.0]). The ratios of 2 nd BV to 1 st BV and 3 rd BV to 1 st BV decreased after admission (P=0.41 and P=0.015 with Wilcoxon rank test, respectively). While the ratio of 2 nd BV to 1 st BV between patients with and without increased HT (1.28 [1.04-1.41] vs. 0.89 [0.67-1.33], p=0.67 with Wilcoxon rank test) was similar, it showed a tendency to rise in patients with infarct growth or recurrence (1.25 [0.78-1.63] vs. 0.80 [0.66-1.21], P=0.11 with Wilcoxon rank test) (Figure). The ratio of 3 rd BV to 1 st BV was higher in patients with increased HT (0.96 [0.82-1.27] vs. 0.72 [0.59-0.81], P=0.25 with Wilcoxon rank test). Conclusion: BV at the 24h post-admission appears to correlate with infarct growth or recurrence during the acute stroke period. BV was likely to persistently increase in patients with HT. Further investigations with a larger dataset are recommended to elucidate the predictive value of 24h BV in acute stroke patients.

Shear rate induced viscosity change of human blood samples and blood mimicking fluids.

Purpose: The aim of this study was to measure blood and blood mimicking fluids viscosity at different shear rates (on the interval of 0.1-5000 1/s and 0.1-10000 1/s) while taking into consideration the measuring device's capability and blood's characteristics. We also provided the measurement results of the most accurate measuring program. Methods: We measured blood samples from five donors, and four different blood mimicking fluid compositions. The measurements were done on an Anton Paar Physica MCR301 rotational rheometer with two measuring programs varying in the shear rate intervals, the number of measuring points and the measuring point durations. Results: The results confirmed the significant shear thinning and thixotropic effects of blood. Blood mimicking fluids also had these characteristics. The measured blood viscosity values are in agreement with those of the literature. Conclusions: It can be concluded that the step test program was able to give more stable results as the measured torque was over the nominal limit of 0.05 ìNm over 0.1 1/s and over the selected torque limit of 0.5 ìNm over 31.6 1/s. Blood mimicking fluid measurement results were different from that of the literature due to different measuring conditions. The sample consisting of water, glycerol and starch mimicked well blood's behaviour and viscosity values at 37 degrees Celsius.

Standardized viscosity as a source of error in computational fluid dynamic simulations of cerebral aneurysms.

Computational fluid dynamics (CFD) simulations are a powerful tool for studying cerebral aneurysms, capable of evaluating hemodynamics in a way that is infeasible with imaging alone. However, the difficulty of incorporating patient-specific information and inherent obstacles of in vivo validation have limited the clinical usefulness of CFD of cerebral aneurysms. In this work we investigate the effect of using standardized blood viscosity values in CFD simulations of cerebral aneurysms when compared to simulations of the same aneurysms using patient-specific viscosity values derived from hematocrit measurements. The objective of this work is to determine the level of error, on average, that is, caused by using standardized values of viscosity in CFD simulations of cerebral aneurysms. By quantifying this error, we demonstrate the need for incorporating patient-specific viscosity in future CFD investigations of cerebral aneurysms. CFD simulations of forty-one cerebral aneurysms were conducted using patient-specific boundary conditions. For each aneurysm two simulations were conducted, one utilizing patient-specific blood viscosity derived from hematocrit measurements and another using a standardized value for blood viscosity. Hemodynamic parameters such as wall shear stress (WSS), wall shear stress gradient (WSSG), and the oscillatory shear index (OSI) were calculated for each of the simulations for each aneurysm. Paired t-tests for differences in the time-averaged maps of these hemodynamic parameters between standardized and patient-specific viscosity simulations were conducted for each aneurysm. Bland-Altman analysis was used to examine the cohort-wide changes in the hemodynamic parameters. Subjects were broken into two groups, those with higher than standard viscosity and those with lower than standard viscosity. An unpaired t-test was used to compare the percent change in WSS, WSSG, and OSI between patient-specific and standardized viscosity simulations for the two cohorts. The percent changes in hemodynamic parameters were correlated against the direction and magnitude of percent change in viscosity, aneurysm size, and aneurysm location. For all t-tests, a Bonferroni-corrected significance level of 0.0167 was used. 63.2%, 41.5%, and 48.7% of aneurysms showed statistically significant differences between patient-specific and standardized viscosity simulations for WSS, WSSG, and OSI respectively. No statistically significant difference was found in the percent changes in WSS, WSSG, and OSI between the group with higher than standard viscosity and those with lower than standard viscosity, indicating an increase in viscosity can cause either an increase or decrease in each of the hemodynamic parameters. On a study-wide level no significant bias was found in either direction for WSS, WSSG, or OSI between the simulation groups due to the bidirectional effect of changing viscosity. No correlation was found between percent change of viscosity and percent change of WSS, WSSG, or OSI, meaning an after-the-fact correction for patient-specific viscosity is not feasible. Standardizing viscosity values in CFD of cerebral aneurysms has a large and unpredictable impact on the calculated WSS, WSSG, and OSI when compared to CFD simulations of the same aneurysms using a patient-specific viscosity. We recommend implementing hematocrit-based patient-specific blood viscosity values for all CFD simulations of cerebral aneurysms.

Relationship between blood viscosity and existence and severity of carotid artery plaque.

Accumulating evidence shows that the increase in blood viscosity (BV) is an independent risk factor for atherosclerosis and its related diseases, but as far as we know, there are few studies on the relationship between blood viscosity and carotid plaque severity. Therefore, we aimed to investigate the relationship between blood viscosity and the presence of carotid plaques, and further explore its relationship with the severity of carotid plaques. We retrospectively analyzed the data of consecutive subjects in the physical examination center of the Affiliated Hospital of Ningbo University Medical College from January 2022 to May 2022.The parameters of blood viscosity include the whole blood viscosity (WBV) at high, middle, and low shear rate, plasma viscosity (PV), hematocrit (HCT), rigidity "k", rigidity index (RI), aggregation index (AI) and electrophoresis rate (ER), and standardized BV calculated by Quemada's equation were included in the study. Carotid plaque score (CPS) was used to measure the severity of carotid artery disease, and participants were divided into mild, moderate, and severe groups according to the quartile of the score. Independent samples t-test and one-way ANOVA were used to compare normally distributed continuous variables between two or more independent groups, respectively. Binary logistic regression was used to evaluate the risk factors of carotid plaque. 314 men were enrolled in the study, of which 165 participants were diagnosed with Carotid artery plaque (CAP) (66.9%). Compared with the CAP- group, the WBV and PV of the CAP+group decreased, but the difference only existed in the PV (p = 0.001). However, standardized BV values (HCT set at 0.45) were higher in the CAP+group than in the CAP- group (3.8643±0.35431vs 3.9542±0.64871, p = 0.188). Regarding the rigidity and aggregation of RBC, the parameters including rigidity "k", RI, AI and ER increased in the CAP+group compared with the CAP- group. The difference was statistically significant in k and ER (p = 0.04, p = 0.009). To assess the severity of carotid plaque, we divided the participants into mild, moderate, and severe groups by using the tertile of CPS value. The mild group was defined as CPS≤0.5 (n = 108), the moderate group as 0.5 < CPS≤1.7 (n = 105), and the severe group as CPS > 1.7 (n = 101). It was found that WBV and PV decreased with the increase of plaque severity, but the difference among the three groups was significant in PV (F = 8.073, p < 0.0001). In addition, with the severity of plaque from mild to severe, standardized BV gradually increased, which were 3.8611±0.34845, 3.8757±0.36637, 3.9007±0.38353 respectively. The difference between the groups was close to statistically significant (F = 2.438, p = 0.089). The values of parameters describing erythrocyte aggregation and rigidity increased among the mild, moderate, and severe groups. The difference was statistically significant in RBC rigidity "k" and ER of RBC (F = 3.863, p = 0.022; F = 5.897, p = 0.003, respectively). Increased blood viscosity is a risk factor for carotid plaque, but its increase may be hidden by decreased hematocrit. Therefore, it is necessary to comprehensively analyze various parameters of blood viscosity, such as the standardized BV calculated by Quemada's equation, which may provide more useful reference value.

Suitability of Different Blood-Analogous Fluids in Determining the Pump Characteristics of a Ventricular Assist Device

Ventricular assist devices (VADs) are implantable turbomachines that save and improve the lives of patients with severe heart failure. In the preclinical evaluation, a VAD design must be experimentally or numerically tested regarding its pump characteristics, primarily for its pressure buildup (pressure head H) since it must provide the cardiovascular system with a sufficient blood flow rate Q. Those pump characteristics are determined on a test bench. Here, a glycerol-water mixture is almost exclusively used as blood-analogous fluid, which should reflect the properties (density, viscosity) of blood as close as possible. However, glycerol water has some disadvantages, such as a higher density compared to real blood and a relatively high cost. Therefore, the study aimed to analyze six different blood analogous fluids to select the most suitable one in consideration of fluid handling, costs, and, most importantly, fluid properties (material and rheological). First, all fluids were mixed to achieve reference values of blood density and viscosity from the literature. Afterwards, the pump characteristics (pressure heads and efficiencies via the VAD) were experimentally and numerically determined and compared among each other and with literature values. Of all six investigated fluids, only the aqueous–polyethylene glycol 200 (PEG 200) solution matches exactly the desired blood properties, and the pump characteristics of this fluid are in the expected range for the analyzed operation point of the VAD. Another advantage is that the cost of the mixture is 35% lower compared to glycerol water. Additionally, we demonstrate that non-Newtonian flow behavior has little effect on the pump characteristics in our VAD.

The Study of Blood Conductivity and Viscosity in Malaria

Malaria is the most widespread disease in Africa and developing countries which has a negative effect on everyday life and causes thousands death each year. To find new, more precise, and less expensive diagnostic methods, an increasing number of studies are needed. In order to replace the conventional method for detecting the presence of malaria parasites in human blood, the electrical conductivity and viscosity of the blood of falciparum malaria were measured. To investigate the effect of malaria on physical properties; a total of hundred blood samples were collected from Khartoum state teaching hospital, samples were subdivided into two groups, fifty from the malaria patient and other fifty from healthy people setting as control group. An Ostwald viscometer, a hematocrit centrifuge and conductivity equipment were used to measure the viscosity, hematocrit and electrical conductivity of blood respectively. In this study it was found that the mean value of hematocrit for healthy individuals was 45.7%. While in malaria patients was 27.7 %, in addition, the mean value of blood viscosity for healthy individuals was 4.4 cp, while 2.8 cp, for patients. The mean value for conductivity of whole blood in healthy individuals was 4.4 m. s, whereas it was 3.9 m.s in patients, but the mean value of serum conductivity was 4.3 in patients a m.s and 8.3 in healthy individuals.&#x0D; Conclusion: The results obtained in this indicated significantly changed in viscosity, hematocrit and electrical conductivity of blood due malaria parasites. These physical changes caused by Plasmodium falciparum malaria can be used as new malaria diagnostic techniques.

Efficacy of Ginkgo biloba Extract Combined with Hormones in the Treatment of Sudden Deafness and Its Effect on the Reactivity of Peripheral Blood T Cell Subsets.

This work was aimed at exploring the efficacy of Ginkgo biloba extract combined with hormones in the treatment of sudden deafness and the influence on the reactivity of peripheral blood T cell subsets (PBTCSs). In this work, 64 patients with sudden deafness who were treated in The First Affiliated Hospital of Hunan University of Traditional Chinese Medicine from August 2019 to August 2022 were selected as the research objects. The patients were randomly divided into a hormone group (treatment with prednisone acetate, n = 34) and a combination group (treatment with Ginkgo-Damole combined with prednisone acetate, n = 30). After the two groups of patients were treated in different ways, their efficacy, symptom improvement, changes in blood rheology, and PBTCSs were compared. The total effective rates (TERs) of the hormone group and the combination group were 76.32% and 95.73%, respectively (P < 0.05). The fibrinogen contents of the patients in the combination group were obviously lower than those in the hormone group after 5 d, 7 d, and 10 d of treatment (P < 0.05). The high blood viscosity (HBV) values of patients in the combination group at 5 d, 7 d, and 10 d after treatment were greatly lower than those in the hormone group (P < 0.05). The low blood viscosity (LBV) values after 3 d, 7 d, and 10 d of treatment in the combined group were much lower in contrast to those in the hormone group (P < 0.05). The CD3+, CD4+, and CD4+/CD8+ in peripheral blood in the combination group were sharply higher while the CD8+ in the combined group was lower in contrast to the hormone group (P < 0.05). There was no visible difference in the incidence of adverse reactions between the two groups of patients after treatment (P > 0.05). In conclusion, the combined application of Ginkgo biloba extract and hormones could effectively improve the abnormal hemorheological indexes of patients with sudden deafness and effectively relieve the imbalance of PBTCSs, which was safe.

Prediction of Blood Viscosity Based on Usual Hematological Parameters in a Clinically Healthy Population Living in a High-Altitude City.

Huamaní, Charles, William Sarmiento, Golda Córdova-Heredia, Luz Cruz-Huanca, Paulina Damián-Saavedra, and Dario Antonio. Prediction of blood viscosity based on usual hematological parameters in a clinically healthy population living in a high-altitude city. High Alt Med Biol. 23:78-84, 2022. Background and Aims: Variations in blood viscosity are mainly determined by the hematocrit level, but in residents of high-altitude cities, the hemoglobin levels and blood viscosity values are often high. We aimed to determine the blood viscosity values in clinically healthy chronic hypoxia-acclimatized individuals and establish a predictive model based on the hematocrit level and other common hematological parameters. Methods: A prospective observational study was conducted in asymptomatic young adults living in Cusco (a city located at 3,399 m). Venous blood samples were collected to determine the hemoglobin, hematocrit, and albumin and serum protein levels and blood viscosity values. Results: Altogether, 253 volunteers were included, of whom 147 (58.1%) were women. The hematological values were mean values of hemoglobin, 16.32 ± 2.0 g/dl; hematocrit, 48.12% ± 5.24%; triglycerides, 130.68 ± 90.64 mg/dl; globulin, 3.07 ± 0.36 g/dl; and mean blood viscosity, 6.17 ± 0.94 centipoises. The prediction model with the highest explained variance (R2 = 68.07%) and parsimony conservation comprised hematocrit, globulin, and triglycerides [blood viscosity = hematocrit × (0.176) + globulin × (0.595) + triglycerides × (1.77/1,000) - 4.13]. Conclusions: In a population living at high altitude, the blood viscosity level is extremely high and mainly determined by the hematocrit level. This population has chronic high blood viscosity levels, which can be predicted using other blood elements.

Blood Viscosity in Subjects With Type 2 Diabetes Mellitus: Roles of Hyperglycemia and Elevated Plasma Fibrinogen.

The viscosity of blood is an indicator in the understanding and treatment of disease. An elevated blood viscosity has been demonstrated in patients with Type 2 Diabetes Mellitus (T2DM), which might represent a risk factor for cardiovascular complications. However, the roles of glycated hemoglobin (HbA1c) and plasma fibrinogen levels on the elevated blood viscosity in subjects with T2DM at different chronic glycemic conditions are still not clear. Here, we evaluate the relationship between the blood viscosity and HbA1c as well as plasma fibrinogen levels in patients with T2DM. The experimental data show that the mean values of the T2DM blood viscosity are higher in groups with higher HbA1c levels, but the correlation between the T2DM blood viscosity and the HbA1c level is not obvious. Instead, when we investigate the influence of plasma fibrinogen level on the blood viscosity in T2DM subjects, we find that the T2DM blood viscosity is significantly and positively correlated with the plasma fibrinogen level. Further, to probe the combined effects of multiple factors (including the HbA1c and plasma fibrinogen levels) on the altered blood viscosity in T2DM, we regroup the experimental data based on the T2DM blood viscosity values at both the low and high shear rates, and our results suggest that the influence of the elevated HbA1c level on blood viscosity is quite limited, although it is an important indicator of glycemic control in T2DM patients. Instead, the elevated blood hematocrit, the enhanced red blood cell (RBC) aggregation induced by the increased plasma fibrinogen level, and the reduced RBC deformation play key roles in the determination of blood viscosity in T2DM. Together, these experimental results are helpful in identifying the key determinants for the altered T2DM blood viscosity, which can be used in future studies of the hemorheological disturbances of T2DM patients.

Blood Viscosity in COVID-19 Patients With Sudden Deafness

BackgroundChanges in blood viscoelastic properties have been proposed previosuly as etiopathogenesis for severe complications in COVID-19 and some cases of Sudden Deafness (SD). This is an attempt to verify if SD cases in patients admitted for SARS-Cov-2 infection can be correlated. Patients and methodsA prospective follow-up was carried out with COVID-19 patients, monitoring their blood viscosity (BV) at high shear rate (300 s−1) and inquiring them periodically for eventual hearing loss. This measurement was extended to cases bearing of SD in 2019 and 2020 without infection and a control group of healthy normoacoustic subjects. ResultsThe normality range was 4,16 ± 0,62 cps. 330 cases admitted for COVID-19 were evaluated from February 24th, 2020 to March 24th, 2021, 85 of them attended in ICU. After anamnesis and Audiometric Tone Thresholds developed as soon as possible, 9 SD were detected, all belonging to ICU group. The mean BV was 4,38 ± 0,43 cps in the ward group, 4,53 ± 0,39 cps in the ICU patients without SD, and 4,85 ± 0,52 cps in the cases with SD, with statistically significant differences. Highest BV elevations in the SD cases were detected between days 6 and 10 of hospital admission. In 2019 four cases consulted with SD, and another two did it in 2020 without a diagnosis of COVID-19, with normal BV values. ConclusionsDuring SARS-Cov-2 infection, patients may show high BV and SS, although an inpatients control group and a larger sample volume are necessary to confirm the predisposition to hyperviscosity. The incidence of hearing damage is considerable if its possible appearance is taken into account, within the limitations of critical patients with COVID-19.

Blood Rheology Alterations in Patients with Cardiovascular Diseases.

Blood rheology is an important determinant of blood flow but is probably one of the most neglected areas in clinical literature and practice. Blood viscosity changes according to shear rates and depends on cellular and plasma factors. RBCs' aggregability and deformability are the main determinants of local flow characteristics in areas with lower and higher shear rates, but plasma viscosity is the main regulatory factor of flow resistance in the microcirculation. In individuals with altered blood rheology, the mechanical stress to vascular walls induces endothelial injury and vascular remodelling, and promotes atherosclerosis. Increased values of whole blood viscosity and plasma viscosity are correlated with cardiovascular risk factors and adverse cardiovascular events. The long-term effects of physical exercise can produce a hemorheological fitness that protects against cardiovascular diseases.

Diagnostic and prognostic value of blood viscosity in acute purulent infection and sepsis

To determine the viscosity of blood, we used a Determan viscometer modified by A.E. Pleshchitser.

Viscosidad sanguínea en pacientes COVID-19 con sordera súbita

AntecedentesLa alteración en las propiedades viscoelásticas de la sangre ha sido anteriormente propuesta como etiopatogenia de complicaciones severas por COVID-19 y algunos casos de sordera súbita (SS). Pretendemos verificar si la aparición de casos de SS en pacientes ingresados por infección por SARS-CoV-2 puede correlacionarse de este modo.Pacientes y métodosEstudio longitudinal prospectivo de pacientes ingresados en nuestro Centro por COVID-19, efectuando monitorización de la viscosidad sanguínea (VS) a alta velocidad de cizallamiento (300 seg-1) y un requerimiento periódico personal sobre hipoacusia. Esta determinación se extendió a casos atendidos por SS sin infección en 2019 y 2020 y un grupo control de sujetos sanos normoacúsicos.ResultadosEl rango de normalidad se situó en 4,16±0,62 cps. Entre el 24 de febrero de 2020 y el 24 de marzo de 2021 se evaluaron 330 casos ingresados por COVID-19, 85 asistidos en la Unidad de Cuidados Intensivos (UCI). Fueron identificadas tras anamnesis y Audiometría Tonal Liminar (ATL) todo lo inmediata que el status clínico lo permitió hasta nueve casos con SS, todos pertenecientes al grupo de UCI. La VS media fue 4,38±0,43 cps en el grupo de sala, 4,53±0,39 cps en los pacientes en UCI sin SS, y 4,85±0,52 cps en los casos con SS, con diferencias estadísticamente significativas. Las mayores elevaciones de la VS en los casos con SS se detectaron entre los días seis y 10 del ingreso hospitalario. En 2019 consultaron cuatro casos y otros 2 en 2020 sin diagnóstico de COVID-19, con valores normales de VS.ConclusionesDurante la infección por SARS-CoV-2 los pacientes pueden presentar elevación en la VS y SS, si bien se hacen necesarios un grupo control hospitalario y un volumen muestral mayor para confirmar la predisposición a la hiperviscosidad. La incidencia del daño auditivo resulta considerable si se tiene en cuenta su posible aparición en pacientes críticos con COVID-19.

An Algorithm for the Noninvasive and Personalized Measurement of Microvascular Blood Viscosity Using Physiological Parameters

Blood viscosity is one of the important parameters to characterize hemorheological properties of the human body. Its real-time and dynamic measurement has important physiological significance for studying the development and prevention of chronic diseases. This study researched noninvasive and personalized measurement of microvascular blood viscosity. In the microcirculation capillary network blood flow model, combined with pulse wave parameters, multiple regression analysis was used to fit the simulated radius of personalized physiological blood vessels to calculate the microvascular blood viscosity. The fitted value related to the simulated radius of the physiological blood vessel had a high correlation with the corresponding theoretically derived value (correlation coefficient: 0.904, P ≤ 0.001). The calculated value of the microvascular blood viscosity had a certain correlation with the clinical whole blood viscosity at a low shear rate (correlation coefficient: 0.443, P < 0.05). This algorithm could provide effective means for noninvasive and long-term individual monitoring and family health care.

Recanalization of Embolized Endovascular Intracranial Aneurysms and Changes in the Blood Viscosity: A Pilot Study.

BackgroundThe purpose of our research was to evaluate the relationships between blood viscosity and recanalization of coiled intracranial aneurysms.Material/MethodsThe study included consecutives patients treated endovascularly by a team of experienced neurosurgeons and neuroradiologists due to brain aneurysm. A total of 50 patients (the average age was 57.48 years, SD=13.71) were assigned to 2 groups: group A with recanalization (4 male and 8 female patients) and group B without recanalization (10 male and 28 female patients) were examined. All patients underwent a 6-month follow-up of the whole-blood viscosity test with a Brookfield DV III+pro cone-plate viscometer using the Rheocalc program. Differences between groups were assessed using the Statistica 12 computer program (StatSoft Inc., Tulsa, OK, USA).ResultsStudies have shown no significant difference in the age range between group A and B (P=0.31). In group A, higher viscosity values were found for whole blood [median: 4.14 dyn×sec/cm2 (mPa×sec) quartile range 0.42], compared to group B [median: 3.92 dyn×sec/cm2 (mPa×sec); quartile range 0.40; (P=0.04)]. This difference was significant (P=0.04). Additionally, the level of hematocrit was positively related with recanalization, the higher the hematocrit, the more frequent recanalization. A very strong and statistically significant relationship occurred between the frequency of recanalization and smoking (P<0.001).ConclusionsThe occurrence of higher values of whole blood viscosity which increase turbulent flow through the vessels may be a risk for recanalization of the coiled intracranial aneurysm.

Relationship between apical thrombus formation and blood viscosity in acute anterior myocardial infarction patients.

Aim: This study sought to investigate the predictive value of whole blood viscosity (WBV) to identify high-risk patients who will develop an apical thrombus during the acute phase of anterior transmural infarction. Materials & methods: Consecutive 1726 patients with first acute anterior myocardial infarction were evaluated. WBV was calculated according to the Simone's formula. Results: Patients with an apical thrombus had prolonged pain to balloon time, higher rate of post-PCI thrombolysis in myocardial infarction flow ≤1 and significantly higher mean WBV values at both shear rates than those without an apical thrombus. Conclusion: WBV values at both shear rates were found to be significant and independent predictors for early LV apical thrombus formation complicating a first-ever anterior wall myocardial infarction.

A non-invasive blood viscosity detecting method based on pulse wave

A non-invasive blood viscosity detection method based on pulse wave is proposed. The method establishes a relationship equation between blood viscosity and peripheral resistance, arterial compliance, and pulse wave waveform characteristics by extracting characteristic parameters of human pulse wave. According to the blood viscosity model established by linear regression analysis, the human blood viscosity value is estimated to achieve non-invasive blood viscosity detection. The experimental results show that the blood using this method. The viscosity is in good agreement with the blood viscosity values measured by the blood viscometer.

Ani Sensörinöral İşitme Kaybında Tam Kan Viskozitesinin Prognostik Değeri

Ani Sensörinöral İşitme Kaybında Tam Kan Viskozitesinin Prognostik Değeri