A $4.5 million grant from the U.S.
government-sponsored National Heart, Lung and Blood Institute is helping
to make medical history. The funds are supporting a collaborative effort
by scientists, doctors and engineers from five research institutions
across the United States to develop a new medical device that will help
save babies' lives.
Baby Isabella was born five days ago. She has a condition called
pulmonary hypertension or high pressure in the lungs, which causes the
heart to fail.
Rushed by helicopter to Children's Hospital in
Pittsburgh, Pennsylvania, she was hooked up to a heart/lung machine, the
same machine routinely used by adults during heart bypass surgery.
Pediatric surgeon Peter Wearden says it is a short-term fix for Isabella.
"It is a very large machine. It requires the children to be completely
relaxed with medicines, to be on a ventilator. Their families can't hold
them. And really, it will only work for about two weeks before they can
develop serious complications that ultimately can be fatal."
For Isabella, two weeks is enough time for her heart to rest. But many
babies waiting for heart transplants need more time. One quarter of the
4,000 babies waiting die before a new heart becomes available.
James Antaki wants to change that. He is associate professor of
biomedical engineering at Carnegie Mellon University in Pittsburgh where
he heads a team working on an infant heart pump.
"It assists part of the heart while the heart is recovering or is too
weak to provide the pressure and flow to keep the baby alive and in some
cases it is used as a bridge to a transplant. You can think of it as a
crutch," Antaki says.
But in this case the crutch can last, not two weeks, but six months.
Antaki says the artificial device must mimic the baby heart.
"The heart itself is a pump. It provides pressure and flow of blood to
all the vital organs of the body and when the heart takes a break there is
really no substitute." "So our device is a booster
pump inserted into the circulation," Antaki says, "and provides a extra
flow or pressure to keep the baby alive and unload the weak heart to give
it a chance to take a break."
Holding a prototype of the pump in his hand, Antaki explains that the
walnut-sized device uses so-called turbo-dynamic technology to delicately
circulate the baby's blood with a tiny turbine: "In our case,[prototype]
is supported by a magnetic bearing or magnetic levitation. A rotor will
spin indefinitely because there is no friction and nothing to wear out and
in the case of a blood pump, it would never damage the blood cells."
Antaki says the challenge is to get the blood to flow at exactly the
proper rate. Pumping too fast could harm blood cells. Pumping too slow
could make the blood clot. Testing so far has been computer-based with
models and simulations, such as the kind engineering graduate student
Dorian Arnold is using on virtual patients. "What this work allows us to
do is test how the pump is going to perform under a whole set of
conditions that are not available to us in the clinic or in animals. In
doing so we can develop controllers that guide how the pump operates when
it is implanted in a patient."
James Antaki says these cyber tools
allow engineers to design components and predict outcomes before actually
building anything. But he adds the prototype is the result of
collaboration among engineers and teams of doctors and research
scientists. "We are really looking forward to the first baby's life that
we save and (to) just feel(ing) good that we made a difference."
Antaki says the infant heart pump will be tested in a baby lamb in
October. He expects the device to be available for a human baby within
three years. |