Fluidic operational amplifier for mock circulatory systems - simulation and experimental results

Abstract. The paper presents a hybrid (hydro-numerical) circulatory model built to be used as a complementary tool for clinical purposes. It was developed at the Institute of Biocybernetics and Biomedical Engineering -Polish Academy of Sciences (Poland) in co-operation with the Institute of Clinical Physiology -National Council of Research (Italy). Main advantages of the model are: 1) high accuracy and repeatability of parameters setting, characteristic of numerical solutions, 2) maximum flexibility achieved by implementing the largest possible number of the model's elements in the numerical way, 3) ability to test mechanical heart assist devices provided by special computer applications; in the model two physically different signal environments -numerical and hydraulic -are connected by special impedance transformers interfacing physical and numerical parts of the model; 4) eliminating flowmeters, as the voltage controlled flow sources embedded in the system provide information on flows.In vitro tests were performed to evaluate the circulatory model: a) modelling and simulation of physiological and pathological states parameters vs. left ventricular end-systolic elastance (E max l ) and rest volume (V o l ) variations, b) testing the effect of LVAD counterpulsation on circulatory hemodynamics and ventricular energetics; it resulted in the increase of total cardiac output (COLV tot) from pathological value 3.8 to 5.4 l·min −1 , mean aortic pressure mPas from 67.8 to 96.1 mmHg and in the decrease of left atrial pressure mP la from 15.7 to 7.7 mmHg and External Work nEW by 37.5%.The model was verified based on literature data.

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“…Paden et al, from The University of California, in their publication on similar gear pump usage [10] confirmed the accuracy of our choice.…”

Section: Introductionsupporting

confidence: 66%

A new hybrid (hydro-numerical) model of the circulatory system

Darowski¹,

Kozarski²,

Ferrari³

et al. 2013

Bulletin of the Polish Academy of Sciences: Technical Sciences

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“…One of the improvements applied in this solution, which enables representation of Frank-Starling low, is the usage of a mathematical model, which allows for determination of ventricular pressure value based on time-dependent elastance function. The determined pressure is a control value for the model of ventricle [10,11] and the resulting deviation between calculated and measured pressure is given to the controller of electric motor with drives a hydraulic piston. That's why displacement pumps will be applied for the modeling of cardiac systolic function.…”

Section: Methodsmentioning

confidence: 99%

A Physical Model of the Human Circulatory System for the Modeling, Control and Diagnostic of Cardiac Support Processes

2014

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Abstract. This study discusses the concept of building and capabilities of the physical model of the cardiovascular system, which will be used for research of the heart support processes. The paper describes the functionality of the system and the data acquisition configuration necessary for the purposes of assist devices modeling, control algorithms development and testing, as well as for implementation of support processes diagnostics. Exemplary hardware for elements representing the selected components of the circulatory system, is presented. Selected measurement devices and methods of pathological conditions modeling are described.

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“…In-vitro mock circulation loops, on the other hand, offer the advantage of directly testing medical devices and investigating physical phenomena that are not fully captured by simplified computational models. However, the ability of mock loops to model the dynamic closed-loop response of the heart remains limited, the challenges including difficulties in achieving realistic end-systolic and end-diastolic pressure-volume characteristics as well as the preload sensitivities of the heart chambers [9][10][11][12][13]. Despite significant advances in computational and in-vitro methods for modeling different aspects of the cardiovascular system, the ability to capitalize these advances in a unified high-fidelity framework is still beyond reach.…”

Section: Current State Of Numerical and In-vitro Methodsmentioning

confidence: 99%

A Hybrid Experimental-Computational Modeling Framework for Cardiovascular Device Testing

Kung

Farahmand

Gupta

2019

Journal of Biomechanical Engineering

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Significant advances in biomedical science often leverage powerful computational and experimental modeling platforms. We present a framework named physiology simulation coupled experiment (“PSCOPE”) that can capitalize on the strengths of both types of platforms in a single hybrid model. PSCOPE uses an iterative method to couple an in vitro mock circuit to a lumped-parameter numerical simulation of physiology, obtaining closed-loop feedback between the two. We first compared the results of Fontan graft obstruction scenarios modeled using both PSCOPE and an established multiscale computational fluid dynamics method; the normalized root-mean-square error values of important physiologic parameters were between 0.1% and 2.1%, confirming the fidelity of the PSCOPE framework. Next, we demonstrate an example application of PSCOPE to model a scenario beyond the current capabilities of multiscale computational methods—the implantation of a Jarvik 2000 blood pump for cavopulmonary support in the single-ventricle circulation; we found that the commercial Jarvik 2000 controller can be modified to produce a suitable rotor speed for augmenting cardiac output by approximately 20% while maintaining blood pressures within safe ranges. The unified modeling framework enables a testing environment which simultaneously operates a medical device and performs computational simulations of the resulting physiology, providing a tool for physically testing medical devices with simulated physiologic feedback.

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Fluidic operational amplifier for mock circulatory systems - simulation and experimental results

Cited by 5 publications

References 13 publications

A new hybrid (hydro-numerical) model of the circulatory system

A new hybrid (hydro-numerical) model of the circulatory system

A Physical Model of the Human Circulatory System for the Modeling, Control and Diagnostic of Cardiac Support Processes

A Hybrid Experimental-Computational Modeling Framework for Cardiovascular Device Testing

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