Getting to the heart of the matter
Engineering student helps create next-generation blood pump
A. Sue Weisler
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Understanding fluid dynamics is as necessary for blood pumps as it is for automobile engines.
For Jonathan Peyton, fluid dynamics played a role in his success with the RIT Baja racecar team and as part of the team working to develop a next-generation blood pump. He has learned to manage both the purr of an engine and the beat of a heart.
Peyton, from Otis, Mass., worked throughout spring quarter with professor Steven Day on the development of a magnetically levitated left ventricular assist device, or MAGLEV-LVAD. The blood pump is a state-of-the-art assistive device that could eventually provide an alternative to heart transplants.
Two of the main challenges for researchers are finding ways to alleviate the mechanical wear and tear on the pump components and prevent damage to the blood as it flows through the device. Student researchers like Peyton have focused on meeting these challenges using mathematical models that estimate mechanical sheer stress experienced by the fluid flow through the pump.
“Part of my thesis is to come up with a design optimization strategy for the impeller of the pump to reduce blood damage,” says Peyton.
The impeller is a bladed component that propels the blood through the pump. It floats within the body of the pump through magnetic levitation. Previous generations of LVADs used mechanical or fluid bearings to support the impeller, but they tended to cause more damage.
“What I’ve done is try to improve the design of the pump using computational fluid dynamic models by running many computer-generated simulations of the pump at various operating points,” says Peyton, who will graduate this spring with a master’s degree in mechanical engineering. “After multiple computer simulations of many design iterations there will be an improved design that they can use for future generations of the impeller.”
Prior to working with Day, Peyton spent several months as a co-op at the University of Rochester Medical Center. He worked with Dr. Karl Schwartz, the head of the echocardiography department, and Daniel Phillips, professor of electrical engineering at RIT, on the design of a mock-circulatory loop. This initial task expanded, and Peyton was later hired to outfit the flow loop with an aortic valve test-chamber for prosthetic valves.
“That dropped me into the world of blood studies, and doing that kind of research pretty much solidified me wanting to get a master’s degree as I enjoyed the research environment. Dr. Day saw the opportunity to have someone he knew was knowledgeable in fluid dynamics, had the basics about blood, and also an interest in turbo-machinery. I was too fitting, apparently,” says Peyton laughing.
More and more bio-technology studies integrate medical expertise with engineering disciplines. The multidisciplinary nature of the LVAD project, with its need for people skilled in fluid mechanics, biology and electronics, attracts a wide range of students, Day says.
“I have been very lucky to advise many student projects that are related to the overall goal of building the next-generation pump. Jonathan’s work is a great example of this,” says Day.
More than 5 million people are at risk for heart disease, according to the American Heart Association, yet there are limited numbers of heart transplants due to availability and compatibility. The LVAD pump is a compelling alternative, Day says, and there are few mechanical devices of any sort designed to run for 10 years with no maintenance.
With graduation upon him, Peyton has several job options. One in particular that looks most appealing is in California with a Baja racing team. Even though he has a strong background in the medical technology field and research experience on the next-generation blood pump, he says his heart lies in cars.
“For now it’s blood; for the future, it’s cars. But I try to keep my options open.”
Steven Day and his team have been working closely with the researchers at the the Utah Artificial Heart Institute to advance blood-pump technology. This spring, Day and his student and post-doctoral teams delivered a functional prototype pump to the institute for further testing.
More information about the advances made in biomedical technologies, including the magnetically levitated, left ventricular assist device, or MAGLEV-LVAD can be found at www.rit.edu/research/biox_story.php?id=4.