Avin
Brigman leads a pretty quiet life, an average life. The 32-year-old
welder lives with his wife and two children just two doors down
from his parents in Imperial, California, a small town 111 miles
east of San Diego. But when a blood clot lodged in his brain
during a midday walk in August, he became a horrible exception,
a young
man whose life was suddenly jeopardized by a stroke.
Brigman’s ordeal began as he was walking to his parents’ house
and felt a “bad headache” coming on. He’d had
migraines before and thought this was just the beginning of one
more head-splitting attack. This time, however, he began feeling
numb along his right side.
“Like most guys I just thought
it would go away,” Brigman says, “but when I couldn’t
move my arm at all I began to think that something must be really
wrong.”
Arriving at
his parents’ house, Brigman called his wife.
She listened to his symptoms and insisted he go to the hospital.
By the time they had driven the 10 miles to Pioneer’s Memorial
in nearby Brawley, Brigman was paralyzed along the whole right
side of his body—a major indicator of stroke.
At the hospital,
however, he became exceptional in a lucky way. The emergency room
doctors were able to confirm the stroke diagnosis
quickly enough to give Brigman a new medication that dissolves
blood clots and restores blood flow to oxygen-starved brain cells.
The doctors used StrokeDoc, a newly developed audiovisual link
that connected them with stroke specialists at UCSD.
The fruit of
a marriage between UCSD’s expertise in both
cell phone engineering and stroke research, StrokeDoc has broken
the vexing rigidity that shackled the practice of
medicine over an audiovisual hookup. Until now the fixed point-to-point
nature of a dedicated wire going from one base station to another
has limited the scope of telemedicine. The flexibility of mobile
connections vastly increases the efficiency of telemedicine and
has the potential to change the way strokes are treated.
Getting
a complete diagnosis in a timely manner is important in all emergency
medicine, but especially in dealing with stroke.
Since 1996, a natural clot-busting enzyme called tPA (thrombolytic
plasminogen activator) has been astoundingly successful in treating
strokes caused by blood clots. It has vastly improved the odds
that patients will survive a stroke with minimal disabilities.
Exciting though that prospect is, tPA has major drawbacks. There
are two kinds of stroke, and if tPA is used to treat one caused
by bleeding into the brain rather than one caused by a blood clot,
the drug will increase the bleeding and result in more brain damage
or even death. The other drawback is that tPA has to be administered
quickly—within three hours of the onset of symptoms. Studies
have shown that, after that time, tPA doesn’t help the brain
cells affected by the stroke.
Physicians at local hospitals are therefore understandably wary
about using tPA without a thorough evaluation by a stroke specialist,
and they are unlikely to administer the drug if such a diagnosis
is delayed. Stroke specialists may not be on staff or on duty when
patients are brought into smaller hospitals; therefore many patients
miss the three-hour window.
“Looking at the data, it is
clear that there is a problem,” says Patrick Lyden, head
of the neurology department at UCSD and one of the principal investigators
on the original study of tPA conducted by a consortium of medical
centers, one of which was UCSD. “The studies have shown that
2 to 5 percent of stroke patients are getting this drug, but the
numbers should be more like 30 percent.”
These
percentages translate into enormous human swuffering and disability.
Stroke is the third leading cause of death (after heart disease
and cancer) and the leading cause of disability in the United States,
afflicting about 700,000 Americans every year.
It was clearly not
possible to get every stroke patient to a specialist within three
hours, so Lyden saw only one
solution: bring the specialist to the patient, via telemedicine.
Doing so, however, would require a vast improvement in technology.
In
a sense, telemedicine has been around ever since a doctor made
the first diagnosis over the telephone. But the term has only been
in use since doctors started using interactive audiovisual systems.
These systems allowed patients and physicians to see and hear each
other even though they were separated by thousands of miles. The
limitation was that they had to be hardwired from one telemedicine
base station to another.
“In regular videoconferencing
both parties are at the end of a single, dedicated wire, so the
doctor has to be on one end of the wire at a TV console and the
patient has to be at the other end,” Lyden says. Getting
each party to these fixed ends of the wire often proves almost as
difficult as getting a stroke expert to the patient on time.
Lyden needed a more flexible system. Something that could reach
patients and doctors anywhere. Like a cell phone.
Luckily enough,
San Diego is home to some of the biggest cellular technology companies
in the world, and UCSD has some of the most
accomplished cellular experts on its faculty. Lyden approached
Ramesh Rao, a professor of electrical engineering at the Jacobs
School of Engineering and director of the UCSD division of the
California Institute for Telecommunications and Information Technology—known
as Cal-(IT)2. He told Rao that they needed to replace their current
system, which was to have a physician jump in a car and race to
one end of a fixed-wire TV console at the hospital.
Making such a replacement proved more difficult than Rao first
imagined. “The features and the quality of the system that
the physicians were asking for turned out to be quite demanding,” he
says.
Lyden was asking for a camera that could be controlled remotely
so that the distant stroke expert could pan and zoom the lens.
That way the neurologist could look at what he wanted, just as
if he were in the room. In addition, the camera would be connected
to a laptop that could go anywhere and would connect instantly
via a cellular connection with another laptop. Either laptop might
be in an airport, at a hospital, or on the golf course.
“The physicians of course don’t
like it when people use the golf course example,” Rao quips.
“They prefer to talk about using the system when they are
stuck in traffic.”
The
data transmission requirements of the system were the most demanding
of all. “The existing software out there was geared
toward transmitting video clips, which are often quite grainy,” Rao
explains. In order to get the kind of video quality necessary for
a correct diagnosis, physicians needed a data transmission rate
of 10 megabits per second on the existing hardwired telemedicine
systems. Using a cellular system would demand compressing the same
quality substantially. “We wanted to get that down to one
megabit per second,” Rao says.
This part of the challenge was met through a collaboration with
Path 1 Network Technologies, a company that had been independently
developing a system to transmit DVD quality video over a cellular
network.
The chief technology officer of Path 1, Ronald Fellman, was a professor
of electrical and computer engineering at UCSD from 1988 to 1996.
In addition to extensive connections
between the University and the cellular industry, UCSD also has
an FCC license for a cellular base station on campus, something
that is important in building a telemedicine cellular network. “We
have a cellular communications infrastructure that is truly one
of a kind,” Rao says. “Usually these base-station licenses
are owned by commercial companies like Verizon or Sprint.”
Rao’s group, in
collaboration with private industry, ended up developing entirely
new software for encoding and transmitting high quality video images,
software that is not yet commercially available. The final application
utilizes University and commercial cell systems, as well as the
Internet, to get the images from one laptop to another. “This
wasn’t just bundling together commercial applications. We
had to go out and develop entirely new ways of doing things,”
Rao says. “The key innovation was managing errors on the wireless
links ...since these links are notoriously prone to error.”
Rao and his group therefore created a system that allowed three
seconds to run more sophisticated error recovery algorithms and
retransmit those packets that had been received in error.
Although the effort involved was immense,
Lyden and Rao say the payoff will be worth it. Once high-quality
video and audio are
available via any cellular connection, telemedicine could be used
for all sorts of emergency applications beyond stroke therapy. “There
are a lot of fields, such as critical care and cardiology, where
there are severe time constraints” on getting the patient
expert care, project director Brett Meyer says.
Once they are freed
from a dedicated, point-to-point system, UCSD physicians might
find themselves providing expert advice for patients
in Anaheim, Arizona or Angola. Rural areas of the United States
that now go begging for qualified general practitioners would have
access to the best specialists in the field.
“The way doctors take care of stroke patients today around
the country is based in part on research done at UCSD over the last
15 to 20 years,” Lyden says. “In the same way, if we
are successful, this methodology will be diffused throughout our
country and throughout the world.”
Once the system is widely available, physicians
at major medical centers will be able to deliver their expertise
anywhere it is
needed, if there is a cellular signal. If a train or airliner crashes
in Helena, Montana, for instance, critical care physicians from
around the country will be able to chip in and help triage patients,
then offer advice to local doctors on their care. A physician on
an Indian reservation or in an Appalachian hollow, who might miss
a diagnosis of dengue fever because he’s never seen it, could
instantly get a second opinion from the foremost tropical disease
experts in the country. The applications are almost limitless.
“Whenever
physicians see what we have developed they say,
‘We’ve got to have one of these,’” Meyer
says.
It took two
years of work by UCSD physicians and engineers, toiling side by
side, to iron out the problems in the new system. Once
the technical difficulties were solved, it was time to test the
system. “We strapped a digital camera to a laptop with bungee
cords and made this little prototype,” Rao says. “Pat
Lyden liked it.”
Shortly thereafter, Lyden and project
director Meyer began placing the new cellular telemedicine stations
in five hospitals, as part
of a scientific study of the system’s effectiveness. Pioneer’s
Memorial in Brawley was the first hospital to get one, just in
time to save Davin Brigman.
Emergency room physicians suspected
stroke immediately when Brigman came in, due to the complete paralysis
on only one side of his
body. They quickly did a CT scan of his brain and then brought
in the StrokeDoc hookup.
“They rolled in a cart with
a flat-screen computer and a camera, and told me I would be talking
to a doctor at UCSD,” Brigman says. Although Brigman thought
it strange to be examined by a computer, he felt it was no stranger
than everything else that had happened to him that afternoon. “It
actually was like he was right there,” Brigman says of Meyer.
“He could see me and knew what I was doing, and there was
no delay.”
Within one
hour of the initial headache, the doctors in Brawley were administering
tPA to Brigman. By the time he was on a helicopter
to UCSD’s Stroke Center that evening, he started to feel
better.
Weeks after the stroke, Brigman says almost all his functions
have returned, except for his sense of taste. “I still can’t
taste anything, so I tend to eat too much,” he says.
Still,
Brigman knows how lucky he is. If his stroke had come even a couple
of months earlier he might never have been given tPA and
might have ended up with severe disabilities despite the best efforts
of the doctors in Brawley. Had this happened, Brigman would have
merely been repeating the experience of thousands of other stroke
victims in small towns across America.
That’s a reality that
UCSD scientists hope to change. “This
technology brings us one step closer to helping people who we have
never been able to help before,” Meyer says. 
Christopher Vaughan has written numerous books and articles on
biomedicine. He lives in the San Francisco Bay Area.
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