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Determination of Blood Pressure
Plch, Miroslav ; Smital, Lukáš (referee) ; Čmiel, Vratislav (advisor)
The thesis includes a general introduction to monitoring and measurement of blood pressure of horses, the design of algorithms for pressure curve detection and the calculation of respiratory variabilities in mechanical ventilation under anaesthesia. The first two chapters focus on anatomy, on characteristics of blood flow and on vascular system. Then it deals with the measurement of blood pressure, monitoring of a horse under anaesthesia and it describes particular thermodynamic parameters. In the following part of the thesis, the methods of pressure curve detection are described. The last part contains the description of an algorithm designed for detection of pressure curve of horses in the environment of the program LabVIEW. The program calculates, displays and saves variabilities of systolic pressure, pulse volume, pressure amplitude, pulse frequency, peripheral resistance and vascular expansion from the detected values.
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Determination of Blood Pressure Parameters for Ventilation Control during Anaestesia in Horses
Horský, Martin ; Provazník, Ivo (referee) ; Čmiel, Vratislav (advisor)
The present work deals with the issue of hemodynamic monitoring of blood pressure in horses during mechanical ventilation in anesthetized horses. Result of this work is an extension to the application Datex-Ohmeda S/5 Collect, which from the pressure curve provides values needed for optimal ventilation. Initial chapter provides a general physiologic introduction. It describes the definition of blood pressure, cardiac cycle and description of the pressure curve. It also deals with the hemodynamic parameters such as pulse pressure, stroke volume and their variabilities. In the second chapter is described methodology of measuring blood pressure in horses. Both, noninvasive and invasive methods are included. The third chapter analyzes fluctuations in blood pressure during ventilation. The last fourth chapter describes the implemented extension module which is designed to monitor hemodynamic parameters of the pressure curve.
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Monitoring of hemodynamics in the departement of Anesteziology and Intensive Care
ZMEŠKALOVÁ, Marie
Monitoring the haemodynamics serves for monitoring and evaluation of data from patient's cardiovascular system by using various technology. At the department of anaesthesiology and resuscitation, it is primarily a nurse who observes the monitoring of the haemodynamics, since she is present at the patient's bed for the whole time of the work shift. She operates and calibrates the invasive monitoring of the haemodynamics. I focused on this department to get the information straight from paramedical staff, about their awareness, abilities to solve the problems related to the haemodynamics and overall orientation. It is the mapping of knowledge of paramedical staff, about the monitoring of the haemodynamics at the department of anaesthesiology and resuscitation. It means to find out the difficulties of monitoring the haemodynamics at the department of anaesthesiology and resuscitation. The hypotheses: The knowledge of paramedical staff about the monitoring of the haemodynamics at the department of anaesthesiology and resuscitation is influenced by the length of professional experience. The knowledge of paramedical staff about the monitoring of the haemodynamics at the department of anaesthesiology and resuscitation is influenced by the education. The research question: What are the difficulties of monitoring the haemodynamics at the department of anaesthesiology and resuscitation? The group of respondents (105) and informants (5) consists of paramedical staff which works at the A&E. In the period between 20.4. - 15.5. 2020. The respondents were not limited neither by the age nor by the professional experience, except for the place of work. There will be used a qualitatively quantitative strategy of the research survey in the empiric part of the diploma thesis. All the research questions and hypothesis were answered by making and processing the research survey. Most of the questions were answered correctly and most of the paramedical staff have sense of their work in the area of the haemodynamics and they understand gained information, which they evaluate in favour of patients. This diploma thesis is dedicated to nurses within the examination of monitoring of the haemodynamics at the department of anaesthesiology and resuscitation. A handbook for newly arrived staff focusing on the monitoring of haemodynamics will be created based on the results of the research. This material will be suggested as a part of basic data for adaptation process.
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Fluid-structure interaction between blood and dissipating artery wall
Fara, Jakub ; Tůma, Karel (advisor) ; Bodnár, Tomáš (referee)
In this thesis we introduce a new fluid-structure interaction model in the Eulerian description. This model is developed for blood flow in viscoelastic artery. For the fluid part a non-Newtonian model Oldroyd-B is used and for the structure part Kelvin-Voigt model is employed. Kelvin-Voigt model will be reached by a limiting process of the Oldroyd-B model. Interface between these two materials is guaranteed by conservative level-set method. Numerical tests of this model is performed by finite element method. This model is used for a simulation of two problems: a two dimensional channel with viscoelastic walls and pulsating inflow and Turek-Hron FSI benchmark. 1
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Application of finite element method to real problems in hemodynamics.
Švihlová, Helena ; Hron, Jaroslav (advisor) ; Dolejší, Vít (referee)
The incompressible fluid flow around the geometries of cerebral artery aneurysms is studied in this thesis. The aneurysm is a local extension of a vessel. This disease is dangerous only in the case of rupture. Then the blood is released into the brain. The need of accurate computation of the velocity and pressure fields in this geometries is motivated exactly by the question which aneurysm has tendency to rupture. The finite element method (FEM) is used for the computation of the flow. A good domain discretization is one of the main step in FEM. Modern computed tomography is able to produce series of the two- dimensional images and it is necessary to create an appropriate three-dimensional model of the tissue. This thesis includes the description of the mesh generation and the ways to smooth and improve the meshes. In the theoretical part the equations of fluid flow are formulated. A suitability of a choice of boundary conditions is discussed. Weak formulation for the equations and its discretization are presented. In the practical part velocity and pressure fields are computed by the various finite elements. Wall shear stress which plays an important role in the evolution of an aneurysm is also computed on the introduced meshes. Comparison of mesh smoothing filters, used finite elements and used...
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Projection method applied to modelling blood flow in cerebral aneurysm
Hrnčíř, Jakub ; Hron, Jaroslav (advisor) ; Knobloch, Petr (referee)
This thesis is motivated by a problem of cerebral aneurysms, which are abnormal bulges on the arteries which supply blood for our brain. These aneurysms can rupture and cause death or permanent neurological deficits. To study the evolution of aneurysms and assess the risk of rupture, mathematical modelling might be used to compute otherwise unobtainable information about blood flow inside the aneurysm. For this reason it is essential to be able to model blood flow in sufficiently high resolution. A goal of this thesis was to implement standard projection method for the solution of unsteady incompressible Navier-Stokes equations using the free finite element software FEniCS to create a working code adjusted to the need of this particular application. The incremental pressure correction scheme was chosen. Various shortcomings of this method are described and a proper choice of boundary conditions and other implementation issues are discussed. A comparison of computed important hemodynamic indicator wall shear stress using new and previously used solution approach are compared. A test of the new code for parallel efficiency and performance on finer meshes for a real medical case was conducted. Powered by TCPDF (www.tcpdf.org)
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Blood flow modeling in arterial stenosis.
Matajová, Adéla ; Hron, Jaroslav (advisor) ; Dolejší, Vít (referee)
Arterial stenosis is a disease characterized by the buildup of a waxy substance inside the artery, which is associated with certain risks. It is difficult to eval- uate the severity of the stenosis, yet the diagnosis can become more accurate using computational fluid dynamics simulations. The present thesis introduces and applies the model of hemodynamics based on the Navier-Stokes equations, implemented in the FEniCS software employing the finite element method. The main focus lies on the prescription of the boundary condition at the outlet of the computational domain. The impact of the outlet boundary condition on medically significant quantities such as the wall shear stress is analyzed in a two- dimensional benchmark case. It appears that the right choice of the boundary condition is fundamental, in particular when vortices occur and propagate across the outlet boundary. The next part of the work is dedicated to the prescrip- tion of the outflow rate in the case of more than one outlet, corresponding to an artery branching inside the computational domain. The physically meaningful flux distribution is derived introducing Murray's law and its extension. Finally, the blood flow is simulated in a three-dimensional geometry of a patient-specific carotid artery. 1
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Hemodynamic optimalization in hepatic recection
Zatloukal, Jan ; Pradl, Richard (advisor) ; Cvachovec, Karel (referee) ; Málek, Jiří (referee)
Lowering of central venous pressure in hepatic surgery is nowadays widely recommended and used procedure. Low central venous pressure anesthesia is associated with decreased blood loss and improved clinical outcome. There are several approaches how to reach low central venous pressure. Till now none of them is recommended as superior in terms of patient safety and clinical outcome. Concurrently there is still debate if to use the low central venous pressure anesthesia principle or if it could be replaced with a principle of anesthesia with high stroke volume variation (or another dynamic preload parameter) with the use of a more sophisticated hemodynamic monitoring method. Results of our study didn't show any significant difference between two approaches used for reduction of central venous pressure, but suggest that the principle of low central venous pressure anesthesia could be possibly replaced by the principle of high stroke volume variation anesthesia which presumes the use of advanced hemodynamic monitoring. KEYWORDS Hepatic resection, central venous pressure, Pringle maneuver, hemodynamics, hemodynamic monitoring, fluid therapy, anesthesia
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Pulmonary pathophysiology during circulatory support.
Popková, Michaela ; Mlček, Mikuláš (advisor) ; Rohn, Vilém (referee) ; Otáhal, Michal (referee)
Introduction: Left-ventricular (LV) distension and consequent pulmonary congestion are complications frequently discussed in patients with severe LV dysfunction treated with veno- arterial extracorporeal membrane oxygenation (VA ECMO). The goal of this study was to describe the influence of high VA ECMO flows to LV distension, lung hemodynamics, and lung fluid accumulation. Methods of LV decompression were studied to prevent lung edema. Methods: In all experiments porcine models under general anesthesia were used. The effects of high extracorporeal blood flow (EBF) on LV heart work were assessed in a chronic heart failure model. The effects of LV afterload on lung fluid accumulation were evaluated by electrical impedance tomography (EIT) on acute heart failure models. Phase and frequency filtration and mathematical analysis were applied to the raw EIT data. Subsequently, mini- invasive techniques of LV decompression were evaluated for LV work. Results: The stepwise increases of VA ECMO flow improved both hemodynamic and oxygenation parameters. Nevertheless, it also caused distension and increased work of LV. The rise in EBF led to increased pulmonary capillary wedge pressure and lung fluid accumulation assessed by EIT in heart failure. The methods for LV decompression (Impella pump, atrial...
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Fluid-structure interaction between blood and dissipating artery wall
Fara, Jakub ; Tůma, Karel (advisor) ; Bodnár, Tomáš (referee)
In this thesis we introduce a new fluid-structure interaction model in the Eulerian description. This model is developed for blood flow in viscoelastic artery. For the fluid part a non-Newtonian model Oldroyd-B is used and for the structure part Kelvin-Voigt model is employed. Kelvin-Voigt model will be reached by a limiting process of the Oldroyd-B model. Interface between these two materials is guaranteed by conservative level-set method. Numerical tests of this model is performed by finite element method. This model is used for a simulation of two problems: a two dimensional channel with viscoelastic walls and pulsating inflow and Turek-Hron FSI benchmark. 1
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