ABSTRACT
ABSTRACT: 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.
Subject(s)
Biocompatible Materials , Heart-Assist Devices , Blood Pressure , Decision Making, Computer-AssistedABSTRACT
An implantable centrifugal blood pump hasbeen developed with original features for a left ventricularassist device. This pump is part of a multicenter and internationalstudy with the objective to offer simple, affordable,and reliable devices to developing countries. Previous computationalfluid dynamics investigations and wear evaluationin bearing system were performed followed byprototyping and in vitro tests. In addition, previous bloodtests for assessment of normalized index of hemolysis showresults of 0.0054 2.46 ¥ 10-3 mg/100 L. An electromechanicalactuator was tested in order to define the bestmotor topology and controller configuration. Three differenttopologies of brushless direct current motor (BLDCM)were analyzed.An electronic driver was tested in differentsituations, and the BLDCM had its mechanical propertiestested in a dynamometer. Prior to evaluation of performanceduring in vivo animal studies, anatomical studieswere necessary to achieve the best configuration and cannulationfor left ventricular assistance. The results wereconsidered satisfactory, and the next step is to test theperformance of the device in vivo.
