scholarly journals Safety Control Architecture for Ventricular Assist Devices

Machines ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 5
Author(s):  
André C. M. Cavalheiro ◽  
Diolino J. Santos Filho ◽  
Jônatas C. Dias ◽  
Aron J. P. Andrade ◽  
José R. Cardoso ◽  
...  
Keyword(s):  
Control System ◽  
Cardiovascular System ◽  
Ventricular Assist Devices ◽  
Ventricular Assist ◽  
Centrifugal Blood Pump ◽  
Safety Control ◽  
System A ◽  
Advanced Control ◽  
Supervisory Control System ◽  
Severe Heart Disease

In patients with severe heart disease, the implantation of a ventricular assist device (VAD) may be necessary, especially in patients with an indication for heart transplantation. For this, the Institute Dante Pazzanese of Cardiology (IDPC) has developed an implantable centrifugal blood pump that will be able to help a diseased human heart to maintain physiological blood flow and pressure. This device will be used as a totally or partially implantable VAD. Therefore, performance assurance and correct specification of the VAD are important factors in achieving a safe interaction between the device and the patient’s behavior or condition. Even with reliable devices, some failures may occur if the pumping control does not keep up with changes in the patient’s behavior or condition. If the VAD control system has no fault tolerance and no system dynamic adaptation that occurs according to changes in the patient’s cardiovascular system, a number of limitations can be observed in the results and effectiveness of these devices, especially in patients with acute comorbidities. This work proposes the application of a mechatronic approach to this class of devices based on advanced control, instrumentation, and automation techniques to define a method to develop a hierarchical supervisory control system capable of dynamically, automatically, and safely VAD control. For this methodology, concepts based on Bayesian networks (BN) were used to diagnose the patient’s cardiovascular system conditions, Petri nets (PN) to generate the VAD control algorithm, and safety instrumented systems to ensure the safety of the VAD system.

scholarly journals Stochastic Modeling and Dynamic Analysis of the Cardiovascular System with Rotary Left Ventricular Assist Devices

2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
Jeongeun Son ◽  
Dongping Du ◽  
Yuncheng Du
Keyword(s):  
Heart Failure ◽  
Cardiac Output ◽  
Pump Power ◽  
Aortic Valve ◽  
Cardiovascular System ◽  
Left Ventricular ◽  
Ventricular Assist Devices ◽  
Left Ventricular Assist Devices ◽  
Ventricular Assist ◽  
Left Ventricular Assist

Left ventricular assist devices (LVADs) have been used for end-stage heart failure patients as a therapeutic option. The aortic valve plays a critical role in heart failure and its treatment with a LVAD. The cardiovascular-LVAD model is often used to investigate the physiological demands required by patients and predict the hemodynamic of the native heart supported with a LVAD. As it is a “bridge-to-recovery” treatment, it is important to maintain appropriate and active dynamics of the aortic valve and the cardiac output of the native heart, which requires that the LVAD pump be adjusted so that a proper balance between the blood contributed through the aortic valve and the pump is maintained. In this paper, we investigate how the pump power of the LVAD pump can affect the dynamic behaviors of the aortic valve for different levels of activity and different severities of heart failure. Our objective is to identify a critical value of the pump power (i.e., breakpoint) to ensure that the LVAD pump does not take over the pumping function in the cardiovascular-pump system and share the ejected blood with the left ventricle to help the heart to recover. In addition, the hemodynamic often involves variability due to patients’ heterogeneity and the stochastic nature of the cardiovascular system. The variability poses significant challenges to understanding dynamic behaviors of the aortic valve and cardiac output. A generalized polynomial chaos (gPC) expansion is used in this work to develop a stochastic cardiovascular-pump model for efficient uncertainty propagation, from which it is possible to rapidly calculate the variance in the aortic valve opening duration and the cardiac output in the presence of variability. The simulation results show that the gPC-based cardiovascular-pump model is a reliable platform that can provide useful information to understand the effect of the LVAD pump on the hemodynamic of the heart.

Mayer Waves in Dogs with Total Artificial Heart

1992 ◽  
Vol 15 (10) ◽  
pp. 601-605 ◽  
Author(s):  
T. Yambe ◽  
S. Nitta ◽  
Y. Katahira ◽  
T. Sonobe ◽  
S. Naganuma ◽  
...  
Keyword(s):  
Artificial Heart ◽  
Maximum Entropy Method ◽  
Power Spectral Analysis ◽  
Entropy Method ◽  
Total Artificial Heart ◽  
Ventricular Assist Devices ◽  
Ventricular Assist ◽  
Mayer Waves ◽  
System A ◽  
Power Spectral

To assess the effect of a total artificial heart (TAH) on the autonomic nervous system a power spectral analysis of the hemodynamics in a TAH animal was done by the maximum entropy method. Two pneumatically driven sac-type ventricular assist devices were implanted as total biventricular bypass (BVB) in adult mongrel dogs to compare the differences between natural heart and TAH. Once the BVB was pumping, the natural heart was electrically fibrillated to constitute the BVB-type TAH model. In the arterial pressure waveform in animals with TAH, respiratory waves were not changed (97.7±24.6%) though Mayer waves were significantly decreased (47.5 ± 22.6%) compared with the animal with a natural heart. These results suggest that prosthetic hemodynamics in the TAH animal affect fluctuations in the cardiovascular system.

scholarly journals Tribology and Crystallinity in pivot bearings of Ventricular Assist Devices

2020 ◽  
pp. 52-62
Author(s):  
Dryelle S Marquiori ◽  
Pamela C Florentino ◽  
Sergio Y Araki ◽  
Isac K Fujita ◽  
Rodrigo LO Basso ◽  
...  
Keyword(s):  
Polyamide 6 ◽  
Aortic Pressure ◽  
Ventricular Assist Devices ◽  
Circulatory Support ◽  
Oxide Ceramic ◽  
Ventricular Assist ◽  
Centrifugal Blood Pump ◽  
Assist Devices ◽  
Poly Ether Ether Ketone ◽  
Before And After

Ventricular Assist Devices are blood pumps used in patients with Congestive Heart Failure who are waiting for a heart transplant. They aim to assist the ventricle to pump out blood in physiological circulation by increasing aortic pressure and decreasing intraventricular pressure. The IFSP Laboratory of Bioengineering and Biomaterials (BIOENG) has been developing an Implantable Centrifugal Blood Pump called CARoL for mechanical circulatory support. The objective of this dissertation is to evaluate the changes in the crystallinity of the polymeric Pivot Bearings supporting the impeller of this pump when subjected to friction generated by rotation of zirconia oxide ceramic shafts. The adopted methodology consisted of submitting new and used samples of: a) bearings set made of polyamide 6; and b) the set made of poly-ether-ether-ketone. Those new and used samples were characterized by X-ray diffraction tests and Infrared Spectroscopy. The diffractograms and spectra obtained were compared to evaluate the bearing crystallinity, for both polymers before and after friction. The tests carried out showed diffractograms and similar spectra for the new and used samples, thus, there are indications that the friction generated by the rotation of the shafts did not change the crystallinity of the polymeric bearings supporting the pump rotor.

Cardiovascular System: Heart Failure, Cardiogenic Shock, Cardiomyopathy

2019 ◽  
Author(s):  
Ben O’Brien ◽  
Simon J Finney ◽  
Alastair G Proudfoot
Keyword(s):  
Heart Failure ◽  
Pulmonary Embolism ◽  
Cardiopulmonary Resuscitation ◽  
Cardiogenic Shock ◽  
Cardiovascular System ◽  
Rapid Development ◽  
Management Strategies ◽  
Ventricular Assist Devices ◽  
Circulatory Support ◽  
Ventricular Assist

Around 2% of adults have heart failure, and the prevalence increases with advancing ages. This may manifest chronically but also acutely. Cardiogenic shock is the most extreme manifestation of acute heart failure, manifesting as the rapid development of life-threatening tissue hypoperfusion and organ dysfunction. The causes and management of these heart failure syndromes are considered in this set of mini reviews with a focus on management of the precipitating etiology, specifically coronary artery disease. The importance of risk stratification and risk-based management strategies in pulmonary embolism as a cause of acute right ventricular failure is discussed. Mechanical support of the failing heart is possible with intra-aortic balloon pumps and ventricular assist devices. These can be used in acutely or chronically and their indications are reviewed herein. Finally, advances in cardiopulmonary resuscitation are considered. This review contains 3 figures, 3 tables, and 57 references. Key Words: cardiovascular system, cardiac tamponade, cardiogenic shock, cardiomyopathy, cardiopulmonary resuscitation, circulatory support, heart failure, mechanical pulmonary embolism

Centrifugal Blood Pump for Temporary Ventricular Assist Devices With Low Priming and Ceramic Bearings

2013 ◽  
Vol 37 (11) ◽  
pp. 942-945 ◽  
Author(s):  
Juliana Leme ◽  
Cibele da Silva ◽  
Jeison Fonseca ◽  
Bruno Utiyama da Silva ◽  
Beatriz Uebelhart ◽  
...  
Keyword(s):  
Ventricular Assist Devices ◽  
Blood Pump ◽  
Ventricular Assist ◽  
Centrifugal Blood Pump ◽  
Assist Devices

Effects of gravity on flow rate estimations of a centrifugal blood pump using the eccentric position of a levitated impeller

2020 ◽  
Vol 43 (12) ◽  
pp. 774-781
Author(s):  
Shuya Shida ◽  
Toru Masuzawa ◽  
Masahiro Osa
Keyword(s):  
Flow Rate ◽  
Ventricular Assist Devices ◽  
Blood Pump ◽  
Accurate Estimation ◽  
Ventricular Assist ◽  
Centrifugal Blood Pump ◽  
Assist Devices ◽  
Flow Estimation ◽  
Magnetically Levitated ◽  
Gravity Direction

Implantable ventricular assist devices are a type of mechanical circulatory support for assisting the pumping of the heart. Accurate estimation of the flow rate through such devices is critical to ensure effective performance. A novel method for estimating the flow rate using the passively stabilized position of a magnetically levitated impeller was developed by our group. However, the performance of the method is affected by the gravity vector, which depends on the patient’s posture. In this study, the effects of gravity on the flow estimation method are analyzed, and a compensation method is proposed. The magnetically levitated impeller is axially suspended and radially restricted by passive stability in a centrifugal blood pump developed by our group. The gravity effects were evaluated by analyzing the relationships between the radial position of the magnetically levitated impeller and the flow rate with respect to the gravity direction. Accurate estimation of the flow rate could not be achieved when the direction of gravity with respect to impeller was unknown. A mean absolute error of up to 4.89 L/min was obtained for flow rate measurement range of 0–5 L/min. However, analysis of the equilibrium of forces on the passively stabilized impeller indicated that the effects of gravity on the flow estimation could be compensated by performing additional measurements of the gravity direction with respect to impeller. The method for compensating the effects of gravity on the flow estimation should improve the performance of therapy with the implantable ventricular assist devices.

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