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Heart-Stopping Research

A rocket engineer scrubs in to save lives

Doctors crowd around the incision, the only part of the patient not covered by the sterile sheets. A machine, monitoring the heartbeat, blips. Armed with specialized equipment, the doctors poke and prod into the exposed piece of flesh. They insert a device that they hope will keep the patient’s blood pumping without relying completely on the heart.

Inside the device, a tiny propeller whirrs, keeping the patient’s bloodstream flowing smoothly. The doctors are very pleased. Suddenly, though, there’s a glitch. The blood isn’t flowing evenly. Some of the patient’s red blood cells, shaped like Frisbees, are shredding from the friction created by the propeller. The damaged cells slow the blood flow down, causing other cells to start bumping into each other. The propeller becomes overworked as it tries to push the growing clumps of cells. Finally, the whirring stops.

An illustration shows how the VAD pump is positioned in the body.

The doctors make frantic adjustments to maintain the patient’s homeostasis as buttons are pushed and the device is quickly replaced.

Bernard J. Rosenbaum (ENGR ’63), a NASA engineer, hustles out of the operating room with the broken pump. In an adjacent research lab, he examines the little machine that fits in the crease of his palm. Unlike the propulsion pumps used in space ships that he is used to fixing, he needs a microscope and tweezers to take this one apart.

While he ponders what went wrong, the patient is wheeled into the recovery room and laid on a comfortable bed of hay. Comfortable? If you’re a calf, it’s comfy. After a few minutes, the 2-year-old cow begins to blink its eyes as it wakes from the anesthesia. Baylor University undergraduates, also known as “calf-sitters,” help the animal stand up. Soon the calf is munching away. Evidently, the bed is tasty.

In the same recovery room, several months after the first calf recovered from surgery, another young cow is trying to maintain her feminine figure. At least it looks that way as she walks on the rotating belt of an oversized treadmill. This calf has an experimental pump implanted near her heart, and it appears that the red blood cells are moving without shredding or clotting because the animal is performing its cardiovascular workout with ease.

The pump is working much better, thanks to troubleshooting by Rosenbaum and his NASA colleagues. After Rosenbaum analyzed the blades that kept jamming with clots of blood cells, he finally came up with a solution: an inducer. It’s a mechanical part that is found on the front of rocket engines. When a space shuttle is moving between blast-off and settling into orbit, the inducer accelerates the uptake of liquid hydrogen and liquid oxygen into the main engine pumps. The slight acceleration helps the fluid to flow smoothly. Likewise, the tiny inducer in the heart pump minimizes the friction and accelerates the blood so the disc-shaped cells don’t rupture.

The success of the pump creates an interesting riddle:

What do you get when you put a rocket scientist, a baby cow, and a propeller in one operating room?

Answer: A MicroMed DeBakeyVAD

Translation: A heart pump that keeps critically ill patients alive while they’re waiting for a donor heart.

The project began when the late David Saucier, a NASA scientist at the Johnson Space Center in Houston, received a heart transplant in 1984. His surgeon, Michael DeBakey from the Baylor College of Medicine, also located in Houston, asked Saucier if his knowledge of rocket engine fuel pumps could be applied to a medical blood pump.

Why not? Pumps are pumps.

Serious discussions about developing the pump began soon after Saucier recovered from surgery. The first models were designed outside work, in whatever spare time the two had between preparing engines for the launch pad and transplanting beating hearts. When the ideas for the ventricular assist device (VAD) began to look promising, NASA stepped in to help fund the research.

Rosenbaum, who specializes in propulsion technology, joined the team of physicians and rocket engineers in 1993. For more than 18 months, he spent much of his time in the research laboratories at Baylor University.

Rosenbaum’s innovations on the heart pump project earned him the NASA Special Achievement Medal in 1997 and a place in the Space Technology Hall of Fame in 1999.

The final model of the heart pump, which was patented in 1996, is only three inches long—about the size of a C-cell battery. In 1998, the first human patient to receive the VAD was a 56-year-old man. Since then, more than 200 adults worldwide have been implanted with the heart pump. The pumps have kept patients’ blood flowing for as long as two years, until a donor heart is available. In some cases, the pump was implanted temporarily to allow a weak heart to heal itself.

Just last year, the U.S. Food and Drug Administration approved the use of the pump in children ages 5 to 16. When the news broke that the pump could be used in pediatric cases, Rosenbaum was, once again, in awe: “I came to NASA in the early 1960s as we worked to land men on the moon,” he says. “I never dreamed I would also become part of an effort that could help save people’s lives.”
—Cara J. Hayden (A&S ’04)

Breakthroughs in the Making

If a large truck and a small car going at the same speed collide, which will exert a greater force?

A student impulsively replies that the truck will exert more force—it is bigger and will obviously smash the car to smithereens. But her tutor disagrees, and the two discuss the question, dropping physics terms with gravitational intensity: momentum, velocity, Newton’s Third Law of Motion. Through the conversation, the student develops a line of reasoning and understands the correct answer: The force is equal.

The enlightened student forges ahead to another question, not even bothering to thank her instructor. But his feelings aren’t hurt, because he doesn’t have feelings—he’s a computer.

Thanks to a $2.5 million grant from the National Science Foundation, a team of Pitt researchers is working to make these point-and-click tutors a reality. Kurt VanLehn, Pitt computer science professor and Learning Research and Development Center senior scientist, is leading the team of cognitive psychologists, computational linguists, and research specialists in the endeavor.

The team is currently recording, transcribing, and analyzing dialogue between students and human tutors. For additional insight into human thought processes, the researchers are also observing individual students whom they have asked to work aloud through problems. The team will then use its members’ discoveries to design tutors that can not only answer simple objective questions—what technology today allows—but can understand open-ended conversation, as well. These automated tutors are expected to be hard at work within the next five to 10 years. They will be affordable, have infinite patience, and won’t ask for days off—except when they come down with the occasional virus.
—Megan Dunchak (A&S ’06)

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