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Document Type:Latin Dissertation
Language of Document:French
Record Number:55052
Doc. No:TL25006
Call number:‭MR46082‬
Main Entry:Karla Andrea Tallar Israel
Title & Author:Contrôle physiologique des assistances ventriculairesKarla Andrea Tallar Israel
College:Ecole Polytechnique, Montreal (Canada)
Date:2008
Degree:M.Sc.A.
student score:2008
Page No:93
Abstract:Ideally, the solution for patients under systolic heart failure (i.e. a reduction of the elasticity of the left ventricle) is heart transplant surgery. Unfortunately, the actual demand of hearts for transplantation cannot be fulfilled due to the lack of donors. A temporal solution for these patients is the implanting of a left ventricular assist device (LVAD). The LVAD is a pump that replaces the function of the left ventricle by generating the blood flow (i.e. cardiac output (CO)) required by the systemic circulation. Depending on the level of activity of the patient (e.g. resting, exercising, etc.) the human body requires different levels of CO. In order to achieve these different CO levels, the LVAD must adjust its rotational speed in a controlled manner. Therefore the design and implementation of controllers capable of automatically adjusting the rotational speed of an LVAD is desirable. In this thesis, we develop a proportional and integrative (PI) rotational speed controller. Our PI controller uses hemodynamic variables (i.e. left ventricular and aortic pressures) and the blood flow provided by the LVAD for calculating the required rotational speed. By means of mathematical models, the cardiovascular and the LVAD systems can be simulated. Since Otto Frank proposed the first mathematical model of the cardiovascular system in 1899, many other models have been proposed. Due to its fidelity, we model the cardiovascular system by utilizing the 4-Winkessel model presented in 1988 by Avanzolini et al. Despite its advantages, the above model does not include the effects of the baroreflex autoregulation system. Due to this reason, in this work we also consider the baroreflex model proposed by Ursino in 1994. Finally, the effects of the CARDIANOVE VII LVAD are investigated. The main contributions of this thesis are the implementation of a more accurate cardiovascular model and the development of a reliable PI controller for the LVAD. By adding the baroreflex model we improved the modeling capabilities of the 4-Winkessel cardiovascular model previously developed. In order to demonstrate the importance of the baroreflex system, we present the simulation results for the cardiovascular system with and without autoregulation. The capabilities of our proposed PI controller are investigated by simulating the cardiovascular requirements for a patient during rest and exercise.
Subject:Applied sciences; Biomedical engineering; 0541:Biomedical engineering
Added Entry:Ecole Polytechnique, Montreal (Canada)