A team of Rice University engineering seniors created a device to lift the weight from the abdomens of obese patients undergoing surgery. The R-Aides device uses suction cups hooked to vacuum to help patients under light sedation breathe. Image: Jeff Fitlow/Rice University |
The best doctors strive to relieve their patients’ burdens.
A physician in Houston asked Rice University
students to help him do so in the most literal way.
A team of bioengineering seniors built a prototype device to
literally lift the weight from obese patients who, while undergoing surgical
procedures, might otherwise have trouble breathing.
The respiratory assist device built by Team R-Aides uses
suction cups attached to a horizontal beam and tied in to a vacuum pump to
gently lift the abdomens of patients who are on their backs and under light
sedation. Though the suspension device would not be suitable for patients under
heavy sedation or who are undergoing abdominal surgery, it could be invaluable
to surgeons performing operations that involved the upper or lower body.
The students—Gabriel Ochoa, Marisa Prevost, Norman Truong,
Daeun Yoon, and Justin Yun—accepted the challenge last fall as their senior
design capstone project, required of most graduates of Rice’s George R. Brown
School of Engineering.
Mehdi Razavi, director of electrophysiology clinical
research at the Texas Heart Institute (THI), brought his idea to Rice last
year. He had had success in the past working with students at the Oshman
Engineering Design Kitchen (OEDK). “One of the highlights of working in the
medical center is working with Rice and Maria (Oden) on senior design
projects,” said Razavi, co-adviser on the project with Oden, OEDK director and
a professor in the practice of engineering education.
He found his inspiration on the job.
“Almost all of these ideas come during a procedure, when you
have the ‘What if?’ moment,” Razavi said. “I was in the midst of a surgical
procedure on a very obese patient when he started snoring, which implies the
airway may be a little bit occluded. We could see that his oxygen levels were
going down, and he was trying to push against his abdominal contents to
breathe.
“I thought if there was a way to support his belly, he would
probably do much better and there would be less chance of having to declare an
emergency and put a breathing tube in,” he said.
Razavi envisioned a device that could not only help patients
breathe by gently relieving pressure on the abdomen, but would also save
hospitals money. “Hospitals aren’t reimbursed by the insurance companies for
medical complications,” he said. “This could help avoid the cost of having to
put a breathing tube in, which is not going to be reimbursed.”
The doctor’s pitch to the Rice students “sounded a little
weird,” Truong said. But a search of the literature by Razavi and the team
turned up no evidence that such a device already existed.
“I would have heard about it,” Razavi said.
“We asked around to see if doctors were interested,” Prevost
said. “It seems like it’s an issue they just deal with. They get assistants to
hold up the weight or pick it up themselves, but when we asked them if they’d
be interested in a device, they said, ‘Yeah, that would be good.'”
Razavi, a cardiologist, installs pacemakers through the
chest and accesses arteries to the heart through the groin. He said he would
use a respiratory assist device “for everything I do. A lot of the time, the
abdominal content pushes down and distorts the whole anatomy of the groin, so I
could use this to hold it back. But I can see it being used in any number of
ways, not only in hospitals and cardiac catheterization labs but also in
outpatient clinics.”
Once they decided noninvasive suction was the proper
approach, the students needed suction cups that would gently caress the skin
without bruising it while maintaining the vacuum. “The cups we used come from
breast pumps,” Yoon explained. “They have flexible rubber rims that conform to
the contours of the skin, so they keep a good seal.”
The cups, which would link to an operating room’s vacuum
system, are suspended from a horizontal beam that bears the weight. The
students and Razavi served as test subjects for the prototype by lying on their
backs with a weighted slab of silicone, which mimics human tissue, on their chests.
“It was a simple, nothing-can-go-wrong test,” Ochoa said. “We had the subjects lie down on a table, and we put 40 lbs of weight on their
stomachs to see how their vitals changed. We expected their CO2
levels to drop—we had a pulse oximeter on them—but we didn’t find a
statistically significant change. But we did find their heart rates increasing
quite a bit to compensate.”
“I got the full 40-lbs treatment,” said Razavi, who also had
the cups attached to his real skin. “The suction was a concern; they left it on
for, I think, a good hour.” The doctor said he took “a good dose” of aspirin
the day before to mimic the condition of patients likely to be on blood
thinners and whose skin would be extra sensitive as a result. “At the end, my
skin was a little red, but there was no bruising,” he said, either after the
test or the next morning.
A provisional patent has been filed for R-Aides’ invention,
which may be developed by Saranas, a medical device company founded by Razavi
and recent Rice alumnus Alex Arevalos. The students said their prototype cost
less than $200 to make. The most expensive components were the custom-printed
plastic connectors fabricated on the OEDK’s 3D printer. Injection molding those
parts would cut the cost even further, they said.
“The device will be very cheap, and the amount of training
required to use it will be nominal,” Razavi said. “And the approval process,
the regulatory pathway, is likely to be quite straightforward. I’ve run this by
a regulatory specialist, and we believe strongly that it’s going to be an FDA
Class 1, which is basically more paperwork than anything else.”
