Biomedical Devices Lab Research Opportunities
Position: Engineering Post-Doc Fellow (2-year stipend) with potential for continued funding
Project Description - In response to the growing shortage of donor organs and the success of ventricular assist devices (VAD) as a bridge-to-transplant, the application of VAD has been expanded to destination therapy (i.e. permanent implant). To gain clinical acceptance, VAD implantation periods will need to be extended for periods greater than 5 years requiring higher pump reliability and performance standards. Currently, VAD controllers cannot predict pump failure modes, such as groundwall insulation failures, short circuits, coil failures, and pump stoppage, which if undetected can quickly lead to catastrophic events (i.e. stroke, death). Another challenge with VAD is their inability to tune pump flow rates to meet the physiologic needs of the patient. Physicians and patients manually set VAD flow rates by adjusting pump beat rates or rpm based upon patient feedback (i.e. how does the patient feel). This approach can lead to hypo-perfusion that may result in insufficient end-organ flow, or hyper-perfusion which may cause septal shift or ventricular suction. Implantable pressure and flow sensors, which are currently used in some VAD monitoring and control, increase the risk for potential failure by amplifying the complexity of the system and increase the cost of this technology. Ideally, a reliable physiologic control system that can automatically adjust the pump output to match the cardiac demand, and an incipient fault detection system that can predict and detect VAD failures, without requiring the integration of implantable pressure and flow sensors is needed. Hence, we are developing a sensorless physiologic control system and an incipient fault detection system for VAD. Our hypothesis is that physiologic control of VAD can be achieved by estimating and maintaining an average VAD pressure head, defined as the differential pressure between the left ventricle (LV) and aorta (ΔP), by using only the measurements of VAD motor revolutions per minute (rpm), current, and voltage. It is also hypothesized that pump failure can be predicted by estimating VAD electrical and mechanical parameters from measurements of current, voltage, and rpm. The study is unique in that it will be the first to develop sensorless physiologic control and incipient fault detection systems that can automatically adjust the pump flow rate to a wide variety of clinical and physical activity conditions and predict pump failures reliably. The fault detection system can assist in the planning of VAD maintenance or replacement prior to a catastrophic failure.
Opportunity – Funding for this position is provided by an American Heart Association Scientist Development Grant. In this position, you will have the opportunity to work with a team of engineers, surgeons, and clinicians at the Cardiovascular Innovation Institute to develop physiologic control and fault detection systems for VAD. In addition, our research team will help you become an independent investigator by offering assistance with manuscripts and grant preparations. Further, 20% of your total time will be allocated to develop your own area(s) of research.
Requirements - A basic understanding of cardiovascular physiology and fundamental engineering. Applicant should have a working knowledge of MatLab (LabVIEW a plus) and control systems/fault detection.
Guruprasad Giridharan, Ph.D.
Assistant Professor of Bioengineering
Cardiovascular Innovation Institute
302 East Muhammad Ali Blvd, room 407
University of Louisville
Louisville, KY 40202