Pathophysiological Determinants Relevant in Blood Pump Control

Daners, Marianne Schmid; Dual, Seraina A.

doi:10.1007/978-3-030-47809-4_18

Cited by 2 publications

(1 citation statement)

References 73 publications

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“…It is very difficult to test these complex physiological control mechanisms in detail in a clinical setting, due to obvious safety and ethical issues. In silico and in vitro simulators offer a versatile platform for optimization of design and testing of these algorithms, by reproducing a large variety of clinically relevant scenarios that challenge device operation and control ( Petrou et al, 2019 , 2018 ; Schmid Daners and Dual, 2020 ). In this paper we tested a stepwise increase of HVAD speed, operated manually.…”

Section: Discussionmentioning

confidence: 99%

Initial clinical validation of a hybrid in silico—in vitro cardiorespiratory simulator for comprehensive testing of mechanical circulatory support systems

Fresiello

Muthiah²,

Goetschalckx³

et al. 2022

Front. Physiol.

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Simulators are expected to assume a prominent role in the process of design—development and testing of cardiovascular medical devices. For this purpose, simulators should capture the complexity of human cardiorespiratory physiology in a realistic way. High fidelity simulations of pathophysiology do not only allow to test the medical device itself, but also to advance practically relevant monitoring and control features while the device acts under realistic conditions. We propose a physiologically controlled cardiorespiratory simulator developed in a mixed in silico-in vitro simulation environment. As inherent to this approach, most of the physiological model complexity is implemented in silico while the in vitro system acts as an interface to connect a medical device. As case scenarios, severe heart failure was modeled, at rest and at exercise and as medical device a left ventricular assist device (LVAD) was connected to the simulator. As initial validation, the simulator output was compared against clinical data from chronic heart failure patients supported by an LVAD, that underwent different levels of exercise tests with concomitant increase in LVAD speed. Simulations were conducted reproducing the same protocol as applied in patients, in terms of exercise intensity and related LVAD speed titration. Results show that the simulator allows to capture the principal parameters of the main adaptative cardiovascular and respiratory processes within the human body occurring from rest to exercise. The simulated functional interaction with the LVAD is comparable to the one clinically observed concerning ventricular unloading, cardiac output, and pump flow. Overall, the proposed simulation system offers a high fidelity in silico-in vitro representation of the human cardiorespiratory pathophysiology. It can be used as a test bench to comprehensively analyze the performance of physically connected medical devices simulating clinically realistic, critical scenarios, thus aiding in the future the development of physiologically responding, patient-adjustable medical devices. Further validation studies will be conducted to assess the performance of the simulator in other pathophysiological conditions.

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Section: Discussionmentioning

confidence: 99%

Initial clinical validation of a hybrid in silico—in vitro cardiorespiratory simulator for comprehensive testing of mechanical circulatory support systems

Fresiello

Muthiah²,

Goetschalckx³

et al. 2022

Front. Physiol.

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Improved estimation of left ventricular volume from electric field modeling

Korn

Dahlmanns

Leonhardt

et al. 2021

Journal of Electrical Bioimpedance

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Volume measurement is beneficial in left ventricular assist device (LVAD) therapy to quantify patient demand. In principle, an LVAD could provide a platform that allows bioimpedance measurements inside the ventricle without requiring additional implants. Conductance measured by the LVAD can then be used to estimate the ventricular radius, which can be applied to calculate ventricular volume. However, established methods that estimate radius from conductance require elaborate individual calibration or show low accuracy. This study presents two analytical calculation methods to estimate left ventricular radius from conductance using electric field theory. These methods build on the established method of Wei, now considering the dielectric properties of muscle and background tissue, the refraction of the electric field at the blood-muscle boundary, and the changes of the electric field caused by the measurements. The methods are validated in five glass containers of different radius. Additional bioimpedance measurements are performed in in-vitro models that replicate the left ventricle’s shape and conductive properties. The proposed analytical calculation methods estimate the radii of the containers and the in-vitro models with higher accuracy and precision than Wei’s method. The lead method performs excellently in glass cylinders over a wide range of radii (bias: 1.66%–2.48%, limits of agreement < 16.33%) without calibration to specific geometries.

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Pathophysiological Determinants Relevant in Blood Pump Control

Cited by 2 publications

References 73 publications

Initial clinical validation of a hybrid in silico—in vitro cardiorespiratory simulator for comprehensive testing of mechanical circulatory support systems

Initial clinical validation of a hybrid in silico—in vitro cardiorespiratory simulator for comprehensive testing of mechanical circulatory support systems

Improved estimation of left ventricular volume from electric field modeling

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