Medical Design Briefs - January 2025 - 27

ing. First, they packed the piezoelectric
transducers
closer
together, enabling
them to provide wider coverage so they
could better target smaller arteries such
as the brachial and radial arteries, which
are more clinically relevant. Second,
they added a backing layer to dampen
redundant vibrations from the transducers,
resulting in improved signal clarity
and tracking accuracy of arterial walls.
In tests, the device produced comparable
results to a blood pressure cuff and another
clinical device called an arterial line,
which is a sensor inserted into an artery
to continuously monitor blood pressure.
While the arterial line is the gold standard
for blood pressure measurement in intensive
care units and operating rooms, it is
highly invasive, limits patient mobility, and
can cause pain or discomfort. The patch
provides a simpler and more reliable alternative,
as shown in validation tests conducted
on patients undergoing arterial
line procedures in cardiac catheterization
laboratories and intensive care units.
n Comprehensive Clinical Validation
Researchers conducted extensive tests
to validate the patch's safety and accuracy.
A total of 117 subjects participated in studies
that evaluated blood pressure across
a wide range of activities and settings. In
one set of tests, seven participants wore the
patch during daily activities such as cycling,
raising an arm or leg, performing mental
arithmetic, meditating, eating meals, and
consuming energy drinks. In a larger cohort
of 85 subjects, the patch was tested
during changes in posture, such as transitioning
from sitting to standing. Results
from the patch closely matched those from
blood pressure cuffs in all tests.
The patch's ability to continuously
monitor blood pressure was evaluated in
21 patients in a cardiac catheterization
laboratory and four patients who were
admitted to the intensive care unit after
surgery. Measurements from the patch
agreed closely with results from the arterial
line, showcasing its potential as a
noninvasive alternative.
" A big advance of this work is how
thoroughly we validated this technology,
thanks to the work of our medical collaborators, "
says Xu. " Blood pressure can be all
over the place depending on factors like
white coat syndrome, masked hypertension,
daily activities or use of medication,
which makes it tricky to get an accurate diagnosis
or manage treatment. That's why
Medical Design Briefs, January 2025
it was so important for us to test this device
in a wide variety of real-world and clinical
settings. Many studies on wearable devices
skip these steps during development, but
we made sure to cover it all. "
n Next Steps
The research team is preparing for largescale
clinical trials and plans to integrate
machine learning to further improve the
device's capabilities. Efforts are also underway
to validate a wireless, battery-powered
version for long-term use and seamless integration
with existing hospital systems.
This article was written by Liezel Labios,
UCSD. For more information, contact
Sheng Xu at shx064@ucsd.edu or
visit www.ucsd.edu.
MD&M West Booth 3054
www.medicaldesignbriefs.com
27
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Medical Design Briefs - January 2025

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