Pediatric Mechanical Circulatory Support Applications for Frequency-Leveraged Piezoelectric Hydraulic Pumps
While the development of ventricular assist devices for the pediatric population has grown and helped these patients in bridge-to-transplantation, the motors used for these devices have remained electromagnetic. Because the physical space requirements for pediatric ventricular assist devices (PVADs) implantation are smaller in children, these motors are susceptible to decreased power output and efficiency as they are scaled down. Piezoelectric actuators, which scale down favorably in terms of power output and efficiency, have yielded novel compact piezoelectric hydraulic pumps in the aerospace industry. The focus of this research is on the development of a ventricular assist driver powered by a miniature piezoelectric hydraulic pump (PHP). This driver is designed to drive a working fluid to an extracorporeal ventricular assist device, also called a blood pump, which has been fabricated at UCLA for bridge-to-transplantation mechanical support. The majority of the focus for this dissertation was on developing a fundamental understanding of the factors that affect the transduction of power from a small scale piezoelectric to the human circulation. Two piezoelectric pumps were developed and mechanically tested. An 8.1 W/kg pump with 3% efficient pump was fabricated. In-vitro studies were carried out to show that the piezoelectric pump could produce physiological pressure and flow rate waveforms for pediatric patients. While the driver could only provide 1 L/min flow to the mock circulation, these studies have laid the groundwork to optimize piezoelectric pump technology for mechanical support applications in the pediatric community.