Model Of Blood Flow Research Articles

Early detection model of normal and abnormal blood flow using pulse Oximetry non-invasive of pregnant heart rate

The heart is an important organ in humans as an identification of early examinations in pregnant women carried out by doctors to determine normal and abnormal pregnancies in the fetus. Heart rate or BPM (beats per minute) is a parameter that indicates the condition of a person's heart. The normal human heart rate ranges from 60-100 beats per minute. In pumping blood throughout the body, the heart then holds it back after being cleaned by the lungs and this is closely related to the level of oxygen flowing in the bloodstream. Humans need sufficient oxygen levels in the body to survive. One of the vital monitoring tools for oxygen levels in the human body is pulse oximetry. Pulse oximetry is usually in units or rooms with high and rapid action cases such as the ICU. From these problems, it is necessary to make a research on a diagnostic instrument model for early detection of normal and abnormal blood flow using non-invasive pulse oximetry, a case study of the heart rate of pregnant women which can be identified early through the max 30100 sensor reading in the form of detecting the heart rate and oximeter, then processed by Arduino uno R3 where arduino uno processes data in the form of heart rate and oxymeter readings so that it can be displayed via a 16x2 LCD, the output is the identification of the value of the heart rate and oximeter input so that the normal and abnormal heart rate conditions are known. The purpose of this study is to detect early pregnant women and fetuses with normal or abnormal blood flow using non-invasive pulse oximetry in which case studies are implemented on the heartbeat of pregnant women. The method used in this study uses the hardware programming method by starting with project planning, research, part testing, mechanical design, electrical design, software design, functional test, integration, overall testing and optimization. The measurement results from the MAX30100 sensor are processed on Arduino UNO R3 and displayed on the LCD screen. The system as a whole can work with energy supply from the power supply. After measuring with a comparator that has been calibrated, the average error value of the measurement is 3.32 %.

312.6: Model for Virtual Vascular Reconstruction in Liver Transplantation Using Computational Fluid Dynamics

Introduction: Computational anatomy is a modern research method that has become available using computer technology and computational fluid dynamics. It is promising to use it for perioperative planning and modeling, including organ transplantation. Aim of study is to prepare investigational model of blood flow in liver during liver transplantation. Matherials and methods: Contrast research was done among 53 men who were patients in surgery departments at Krasnoyarsk regional hospital #1, Russia (KRH). Estimations were made using 3D models of portal system (working stations GE Advantage Workstation, Siemens singo.via), based on multi-slices computed tomography of abdominal cavity with bolus contrasting with help of medication “Ultravist-370”. The volume of the used contrasting stuff made 100 ml, the speed of infiltration was 4 ml per second, and the average radial strain was 11,3 m3v. DICOM data segmentation was performed using Dragonfly software (Object Research Systems, Canada) at the Innovation Technology Management Resources of the Reaviz University. Using series with arterial and vein contrast, we performed the segmentation of contrasting vessels, and obtained three-dimensional data topology in.obj format. Then we processed the obtained models using scripts prepared for the pythonOCC framework. We built the central lines of the vessels and formed the branching tree. Methods of computational hemodynamics were implemented using the Visual-CFD application for OpenFOAM environment (ESI, France). Mesh example of portal vein shown in figure 1.Results: With the use of created three-dimensional computer model, the blood flow in the portal vein and liver arteries at various variants of its structure was simulated. It was obtained that, in the presence of the main type of structure with predominance of blood flow along the splenic vein, the blood flow turbulence and risk of thrombosis development are higher. At the same time, with virtual thrombosis of the portal vein trunk, the pressure gradient is 1.4 times higher than with the bulk type, which is more favorable for the proposed reconstruction. Thus, these data can be used for preoperative planning in surgical treatment of portal vein thrombosis in liver transplantation. Conclusion: The proposed model of blood flow is promising and allows you to create an interactive tool for calculating the hemodynamic situation in various reconstructions during liver transplantation.

Blood Flow Modeling in Constricted Arteries Under Body Acceleration and Wall Slip Using Two-Layered Bingham Plastic Fluid

Analysis is done on a two-layered Bingham Plastic model of restricted, thin arteries with periodic body acceleration. The model essentially consists of a centre layer with a core of suspended red blood cells and an outer layer with a peripheral plasma layer. It has been assumed that the rheology of blood in the core region has been classified as a Newtonian fluid with the PPL and a non-Newtonian fluid obeying the law of Bingham plastic model. This model has been used to investigate how blood flow in stenotic arteries is affected by body acceleration, the non-Newtonian character of blood, and a velocity slip at the wall. Analytical equations for axial velocity, flow rate, wall shear stress, and apparent viscosity are produced by using the perturbation method, and their variations with respect to various parameters are shown in the figures and explained in this article. Due to a wall slip, it is seen that while velocity and flow rate rise, effective viscosity falls. The impact of body acceleration significantly increases flow rates and speed. The physiological effects of this theoretical modelling for blood flow conditions are also briefly looked at.

A cell-based smoothed finite element model for non-Newtonian blood flow

Smoothed Finite Element Method (S-FEM) has drawn increasing attention in the field of computational fluid dynamics (CFD) and the present work seeks to make further contribution to this growing field of S-FEM by simulating for the non-Newtonian blood flow. This investigation took the form of Streamline Upwind Petrov-Galerkin in conjunction with Stabilized Pressure Gradient Projection (SUPG/SPGP) to alleviate the spatial oscillation and instability problems. The validation of the cell-based S-FEM (CS-FEM) combined with SUPG/SPGP was carried out by the blood flow over a backward-facing step. The performances of the presented method were explored by the blood flow in the carotid bifurcation and blood flow in the intracranial segment of internal carotid artery. Impressively, the results exhibit good features of the CS-FEM on solving severely distorted mesh vis-a-vis the standard finite element method (FEM). The presented method could realize the accurate prediction in the mentioned complex blood flows as the same as Finite Volume Method software STAR-CCM+.

Peristaltic pumps adapted for laminar flow experiments enhance in vitro modeling of vascular cell behavior

Endothelial cells (ECs) are the primary cellular constituent of blood vessels that are in direct contact with hemodynamic forces over their lifetime. Throughout the body, vessels experience different blood flow patterns and rates that alter vascular architecture and cellular behavior. Because of the complexities of studying blood flow in an intact organism, particularly during development, the field has increasingly relied on in vitro modeling of blood flow as a powerful technique for studying hemodynamic-dependent signaling mechanisms in ECs. While commercial flow systems that recirculate fluids exist, many commercially available pumps are peristaltic and best model pulsatile flow conditions. However, there are many important situations in which ECs experience laminar flow conditions in vivo, such as along long straight stretches of the vasculature. To understand EC function under these contexts, it is important to be able to reproducibly model laminar flow conditions in vitro. Here, we outline a method to reliably adapt commercially available peristaltic pumps to study laminar flow conditions. Our proof-of-concept study focuses on 2D models but could be further adapted to 3D environments to better model in vivo scenarios, such as organ development. Our studies make significant inroads into solving technical challenges associated with flow modeling and allow us to conduct functional studies toward understanding the mechanistic role of shear forces on vascular architecture, cellular behavior, and remodeling in diverse physiological contexts.

An Extended Thermodynamics Model for Blood Flow

A model for blood flow is introduced in the context of the Rational Extended Thermodynamics (RET). The balance equations are applied to the two-hierarchy structure recently introduced by Ruggeri and Sugiyama. The constitutive relations are derived with universal physical principles and the remaining constitutive functions are evaluated by use of the kinetic theory. The model herein obtained is a hyperbolic generalization of a classical blood flow model. Our equations by construction have the same physical proprieties of the classical system; in addition, owing to its hyperbolic structure, our model avoids the unphysical feature of instantaneous diffusive effects which is typical of parabolic systems. Furthermore we expect that our model, as all RET systems, can describe the physical phenomena better than the classical ones when the fields change rapidly or one has steep gradients.

Peristaltic analysis of Williamson blood flow model with solar biomimetic pump

Mathematical model of peristaltic motion for Williamson blood flow through esophagus is addressed with the coordination of biomimetic solar based pump. The transfer of heat and mass is examined under the assumption of diversified viscosity, diffusivity and conductivity. The novelty of the present manuscript is the consolidation of vertical peristaltic system, blood flow over an esophagus, biomimetic solar pump, variable thermo-physical properties, involvement of activation energy for chemical reaction. For the implementation of solar mimetic system, the equations are modeled under the presence of Rosseland's approximation and taking the assumption of long wavelength and small Reynolds number. The application of activation energy is seems through the chemical reaction which is taken near the walls of esophagus. We concluded that the velocity profile reveals the parabolic behavior and Williamson as well as viscosity parameter reduces the velocity fields. The pumping augmented pumping and free pumping areas are addressed. The temperature distributions are exhibits in the form of straight lines and we concluded that thermal conductivity and radiation parameters boost the temperature profile. The activation energy and diffusivity parameter decreases the concentration distribution. Streamlines for peculiar quantities of Weissenberg number and volumetric flow rates are derived and isothermal contour is also examined.

Mathematical Modeling of LDL-C and Blood Flow through an Inclined Channel with Heat in the Presence of Magnetic Field

This investigation revealed that LDL-C and blood flow through an inclined channel with heat in the presence of magnetic field. In this study,mathematical models were formulated for LDL-C and blood flow and energy transfer as a coupled system of partial differential equations (PDEs), the PDEs were scaled using the dimensionless quantities to dimensionless partial differential equations, they are further reduced to an ordinary differential equations (ODEs) using the perturbation method involving the oscillatory term, the governing equations are solved directly using the method of undetermined coefficient. The velocity and temperature functions are obtained with some governing parameters involved, and simulation codes were developed using Mathematica to study the effect of entering parameters on the profiles, and are found to be effective in controlling the flow profiles. It is observed that the governing parameters influenced the flow profiles; also the angle of inclination also influences the flow profile.
 HIGHLIGHTS
 
 Heart attack occurs when blood flow decreases or blood stopped from entering the heart, thereby causing damage to the heart muscle
 Atherosclerosis is an inflammatory disease resulting in the pathological alteration of the intima and media of arteries such as e.g. the aorta
 Use mathematical models to investigate the pulsating flow of blood in an atherosclerotic artery in an inclined fashion
 Carrying out numerical simulation using Mathematica to investigate the impact of the model parameters on the velocity and temperature distribution of the blood. The analysis is relevant in the sense that it helps determine how best clinicians can administer treatment and care
 
 GRAPHICAL ABSTRACT

Automated generation of 0D and 1D reduced-order models of patient-specific blood flow.

Three-dimensional (3D) cardiovascular fluid dynamics simulations typically require hours to days of computing time on a high-performance computing cluster. One-dimensional (1D) and lumped-parameter zero-dimensional (0D) models show great promise for accurately predicting blood bulk flow and pressure waveforms with only a fraction of the cost. They can also accelerate uncertainty quantification, optimization, and design parameterization studies. Despite several prior studies generating 1D and 0D models and comparing them to 3D solutions, these were typically limited to either 1D or 0D and a singular category of vascular anatomies. This work proposes a fully automated and openly available framework to generate and simulate 1D and 0D models from 3D patient-specific geometries, automatically detecting vessel junctions and stenosis segments. Our only input is the 3D geometry; we do not use any prior knowledge from 3D simulations. All computational tools presented in this work are implemented in the open-source software platform SimVascular. We demonstrate the reduced-order approximation quality against rigid-wall 3D solutions in a comprehensive comparison with N=72 publicly available models from various anatomies, vessel types, and disease conditions. Relative average approximation errors of flows and pressures typically ranged from 1% to 10% for both 1D and 0D models, measured at the outlets of terminal vessel branches. In general, 0D model errors were only slightly higher than 1D model errors despite requiring only a third of the 1D runtime. Automatically generated ROMs can significantly speed up model development and shift the computational load from high-performance machines to personal computers.

Blood flow modeling reveals improved collateral artery performance during the regenerative period in mammalian hearts.

Collateral arteries bridge opposing artery branches, forming a natural bypass that can deliver blood flow downstream of an occlusion. Inducing coronary collateral arteries could treat cardiac ischemia, but more knowledge on their developmental mechanisms and functional capabilities is required. Here we used whole-organ imaging and three-dimensional computational fluid dynamics modeling to define spatial architecture and predict blood flow through collaterals in neonate and adult mouse hearts. Neonate collaterals were more numerous, larger in diameter and more effective at restoring blood flow. Decreased blood flow restoration in adults arose because during postnatal growth coronary arteries expanded by adding branches rather than increasing diameters, altering pressure distributions. In humans, adult hearts with total coronary occlusions averaged 2 large collaterals, with predicted moderate function, while normal fetal hearts showed over 40 collaterals, likely too small to be functionally relevant. Thus, we quantify the functional impact of collateral arteries during heart regeneration and repair-a critical step toward realizing their therapeutic potential.

Parameter estimation in fluid flow models from aliased velocity measurements

Parameter estimation in blood flow models from measured velocity data—as e.g. velocity-encoded MRI—is a key step for patient-specific hemodynamic analysis. However, velocity encoding suffers from competing noise and aliasing artifacts, which negatively impact the parameter estimation results. The aim of this work is to propose a new inverse problem formulation capable of tackling aliased and noisy velocity MRI measurements in parameter estimation in flows. The formulation is based on a modification of the quadratic cost function for velocity measurements. This allows for a correct parameter estimation when they have influence on the whole measurement domain, in spite of aliasing artifacts. The new inverse problem can be solved numerically using any standard solver, and we show how a popular sequential approach can be applied. Numerical results in an aortic flow show robust parameter estimation for velocity encoding ranges until 30% of the maximal velocity of the problem, while the standard inverse problem fails already for any encoding velocity smaller than the true one. Moreover, the parameter estimation results are even improved for reduced velocity encoding ranges when using the new cost function. The presented approach allows therefore for great flexibility in personalization of blood flows models from MRI data commonly encountered in the clinical context.

Application of computational fluid dynamics (CFD) and fluid-structure interaction (FSI)in biofluids simulation to solve actual surgery tasks

Computational fluid dynamics (CFD) is a dynamically developing tool in me-chanical engineering and interdisciplinary research. Medicine is one of the areas, where the application of current computational methods is extremely necessary. This study presents the results of using computational fluid dy-namics methods to solve actual problems of surgery (modeling of blood flow in the patient-specific aorta of a child with congenital heart disease during bypass surgery; modeling of the flow of bile in the biliary system to predict cholecystectomy outcome; modeling of the chime flow in the colon). Simu-lation of blood flow in the aorta during shunting. Cardiovascular diseases are most common in the population and cause the prevailing part of premature mortality and disability in both adults and children. Blalock-Taussig shunt-ing is mainly used to eliminate pathological changes in children. However, this procedure is carried out empirically: surgeons use their own experience. FSI enabled to numerically evaluate the shunt parameters and its location for proper lung development in children with congenital heart disease after shunt installation. Biomechanical analysis of the bile flow in healthy state, pathology, and after cholecystectomy. Cholecystectomy (removal of the sur-gical gallbladder) is usually taken to treat patients suffering from gallbladder disease and gallbladder pain. However, it should be noted that the results of the operation are not always successful. The biomechanical patient-specif-ic model was created to assess the cholecystectomy outcome. Study of the chyme flow features in the colon. The large intestine is a long hollow muscle tube of complex shape, which digests and absorbs nutrients and water from food (which is commonly called chyme in medicine). The goal is to create a patient-specific model of the chyme and feces flow in the colon in the healthy state and pathology. Clinical applications of this model can be ex-pressed in the description and understanding of the causes of the disorders as well as drug efficiency assessment to reduce the number of patients.

Effects of electro-osmotic and double diffusion on nano-blood flow through stenosis and aneurysm of the subclavian artery: numerical simulation

Most computational models assumed that blood flow through the stenosis flow in a straight tube. Actually, arteries or blood vessels are rarely straight conduits and stenosis on bends or curves is not uncommon but occurs in the aorta, subclavian artery, and other curved arteries. Therefore, this paper's mathematical modeling of blood flow was done through curvilinear coordinates. The motivation of this paper is to study the effect of double-diffusion convection through curved artery having stenosis and aneurysm regions, the blood flow is modeled as nano-Bingham Papanastasiou fluid under the influence of the electro-osmotic field. Governing equations of the flow are derived using the mild stenosis approximation and solved numerically using the finite difference method. Velocity, temperature, concentration, nanoparticle volume fraction, flow rate, impedance, and shear stress at the throat of aneurysm and stenosis through curved artery are computed numerically and the results are represented graphically. The flow through straight arteries is included as a special case of curved arteries at . Finally, the flow rate in the straight arteries is more than in curved, but shear stress and impedance are greater in curved than the straight arteries. The blood flow velocity is improved in the presence of the electro-osmotic field.

Nonlinear lumped-parameter models for blood flow simulations in networks of vessels

To address the issue of computational efficiency related to the modelling of blood flow in complex networks, we derive a family of nonlinear lumped-parameter models for blood flow in compliant vessels departing from a well-established one-dimensional model. These 0D models must preserve important nonlinear properties of the original 1D model: the nonlinearity of the pressure-area relation and the pressure-dependent parameters characterizing the 0D models, the resistance R and the inductance L, defined in terms of a time-dependent cross-sectional area subject to pressure changes. We introduce suitable coupling conditions to join 0D vessels through 0D junctions and construct 0D networks preserving the original 1D network topology. The newly derived nonlinear 0D models are then applied to several arterial networks and the predicted results are compared against (i) the reference 1D results, to validate the models and assess their ability to reproduce good approximations of pressure and flow waveforms in all vessels at a much lower computational cost, measured in terms of CPU time, and (ii) the linear 0D results, to evaluate the improvement gained by including certain nonlinearities in the 0D models, in terms of agreement with the 1D results.

Local well-posedness of a three-dimensional phase-field model for thrombus and blood flow

In this article we consider a fluid–structure interactions model on a three dimensional bounded domain, that describes the mechanical interaction between blood flow and a thrombus with Hookean elasticity. The interface between the two phases is given by a smooth transition layer, diffuse with a finite thickness. We derive various a priori estimates and prove local well-posedness results using the Faedo–Galerkin method.

Modeling of the cerebral blood circulation in a capillary network accounting for the influence of the endothelial surface layer

Background and objectiveThe paper describes a mathematical model of blood flow in capillaries with accounting for the endothelial surface layer (ESL). MethodThe influence of ESL is modeled by a boundary layer with zero flow velocity. Finite element modeling and an analytical approach based on the homogenization of the core region of blood flow occupied by erythrocytes are developed to describe the resistance of a capillary. The reliability of the results obtained is verified for different values of the discharge hematocrit and vessel diameter using known in vivo data. ResultsThe proposed approach is applied to the numerical simulation of blood circulation in a capillary network of the germinal matrix of infants born at 25 gestational weeks. The influence of the hematocrit level and effective thickness of ESL on the resistance of the capillary network of the germinal matrix of preterm infants is studied. It was found that a decrease in the effective thickness of ESL in the capillary network (and/or a decrease in the hematocrit) leads to reducing the resistance of the capillary network. ConclusionA decrease in the effective thickness of ESL in the capillary network leads to an increase in the pressure drop in arterioles, which may be considered as an additional risk factor for hemorrhages in fragile blood vessels within the germinal matrix.

Roll of Newtonian and Non-Newtonian Motion in Analysis of Two-Phase Hepatic Blood Flow in Artery during Jaundice

Biomathematics is an interdisciplinary subject consisting of mathematics and biology, which is widely applicable for the analysis of biological problems. In this paper, we provide a mathematical model of two-phase hepatic blood flow in a jaundice patient’s artery. The blood flow is thought to be a two-phased process. The clinical data of a jaundice patient (blood pressure and hemoglobin) is gathered. To begin, hemoglobin is transformed into hematocrit, and blood pressure is turned to a decline in blood pressure. For the examination of hepatic arteries in Newtonian and non-Newtonian movements, a mathematical model is constructed. The relationship between two-phase blood flow flux and blood pressure reduction in the hepatic artery is established. For various hematocrit levels, the blood pressure decrease is determined. The patient’s states are defined by the slope of the linear relationship between computed blood pressure decrease and hematocrit.

A proof-of-concept study for the simulation of blood flow in a post arterial segment for different blood rheology models.

Cardiovascular disease (CVD) and especially atherosclerosis are chronic inflammatory diseases which cause the atherosclerotic plaque growth in the arterial vessels and the blood flow reduction. Stents have revolutionized the treatment of this disease to a great extent by restoring the blood flow in the vessel. The present study investigates the performance of the blood flow after stent implantation in patient-specific coronary artery and demonstrates the effect of using Newtonian vs. non-Newtonian blood fluid models in the distribution of endothelial shear stress. In particular, the Navier-Stokes and continuity equations were employed, and three non-Newtonian fluid models were investigated (Carreau, Carreau-Yasuda and the Casson model). Computational finite elements models were used for the simulation of blood flow. The comparison of the results demonstrates that the Newtonian fluid model underestimates the calculation of Endothelial Shear Stress, while the three non-Newtonian fluids present similar distribution of shear stress. Keywords: Blood flow dynamics, stented artery, non-Newtonian fluid. Clinical Relevance- This work demonstrates that when blood flow modeling is performed at stented arteries and predictive models are developed, the non-Newtonian nature of blood must be considered.

Fluid structure interaction versus rigid-wall approach in the study of the symptomatic stenosed carotid artery: Importance of wall compliance and resilience of loose connective tissue.

The purpose of this paper is to demonstrate the importance of a compliant wall approach in modeling of non‐Newtonian and non‐physiological blood flows. A case study of a stenosed and symptomatic carotid bifurcation was considered to show the influence of the wall‐resilience assumption on the flow parameters obtained with numerical simulations. Patient‐specific data concerning the geometry and flow conditions were collected and used to carry out two‐way coupled fluid structure interaction simulations of the pulsatile blood flow through carotid artery. The wall compliance was considered separately as related to the wall‐elasticity and as associated with the reaction of the loose connective tissue surrounding the carotid bifurcation. The obtained hemodynamic parameters were compared to those which were found in rigid‐wall simulations. The difference between the results obtained for rigid‐wall and compliant‐wall approaches for the peak‐systolic area‐averaged wall shear stress achieved 35%, whereas the difference between the time‐averaged local vorticity and shear strain reached, respectively, 42% and 43%. The influence of the highly resilient wall on the monitored hemodynamic parameters was significant even if time‐averaged values are compared, which suggests that these metrics are considerably overestimated if the wall compliance is not considered. Moreover, the findings show that the mechanical response of the loose connective tissue cannot be neglected in blood flow simulations. Additionally, this study indicates that stiffening of the arterial wall due to atherosclerosis significantly rises hemodynamic parameters. This explains the therapeutic benefits of surgical removal of plaque lesions formed in the carotid bifurcation (endarterectomy).

A coupling strategy for a first 3D-1D model of the cardiovascular system to study the effects of pulse wave propagation on cardiac function

A key factor governing the mechanical performance of the heart is the bidirectional coupling with the vascular system, where alterations in vascular properties modulate the pulsatile load imposed on the heart. Current models of cardiac electromechanics (EM) use simplified 0D representations of the vascular system when coupling to anatomically accurate 3D EM models is considered. However, these ignore important effects related to pulse wave transmission. Accounting for these effects requires 1D models, but a 3D-1D coupling remains challenging. In this work, we propose a novel, stable strategy to couple a 3D cardiac EM model to a 1D model of blood flow in the largest systemic arteries. For the first time, a personalised coupled 3D-1D model of left ventricle and arterial system is built and used in numerical benchmarks to demonstrate robustness and accuracy of our scheme over a range of time steps. Validation of the coupled model is performed by investigating the coupled system’s physiological response to variations in the arterial system affecting pulse wave propagation, comprising aortic stiffening, aortic stenosis or bifurcations causing wave reflections. Our first 3D-1D coupled model is shown to be efficient and robust, with negligible additional computational costs compared to 3D-0D models. We further demonstrate that the calibrated 3D-1D model produces simulated data that match with clinical data under baseline conditions, and that known physiological responses to alterations in vascular resistance and stiffness are correctly replicated. Thus, using our coupled 3D-1D model will be beneficial in modelling studies investigating wave propagation phenomena.