First Real-Time Detector for IV Drugs May Help Eliminate Medical Errors
Sep. 19, 2013 — Today,
computerized smart systems can deliver drugs intravenously in exact
volumes to hospital patients. However, these systems cannot recognize
which medications are in the tubing nor can they determine the
concentration of the drug in the tubing. This lack of precise
information can lead to medication errors with serious consequences.
a) The
surface of the new drug sensor was made from a flexible plastic sheet
covered with gold domes. b) This is a close-up of the sensor's surface
taken with a scanning electron microscope (SEM). Each of the domes
visible in the image is less than one millionth of a meter wide. c) The
sensor incorporated with a plastic cell that can be connected in series
with IV tubing used to bring drugs to a patient. d) A schematic
illustration of the new IV drug sensor. A laser is focused onto the
sensor's surface, over which the IV-delivered drugs flow. (Credit:
Hsin-Yu Wu, Nano Sensors Group, University of Illinois)
Now, a new optical device developed by a team of electrical and
computer engineering students at the University of Illinois at
Urbana-Champaign (UIUC) can identify the contents of the fluid in an
intravenous (IV) line in real-time, offering a promising way to improve
the safety of IV drug delivery. The team, led by Prof. Brian T.
Cunningham, interim director of the Micro and Nanotechnology Laboratory
at UIUC, will present its work at The Optical Society's (OSA) Annual
Meeting, Frontiers in Optics (FiO) 2013, being held Oct. 6-10 in
Orlando, Fla.
The vulnerability of IV drug-delivery systems due to human error is a
chief concern in hospital safety, Cunningham said. Errors can include
incorrect dosage, unintentional substitution of one drug for another,
and co-delivery of incompatible drugs.
"Up to 61 percent of all life-threatening errors during
hospitalization are associated with IV drug therapy," Cunningham said,
citing a recent report. "So for all the really good things hospitals can
do, the data shows that mistakes can occasionally happen."
To approach this problem, Cunningham and colleagues turned to the
very small -- to structures and processes at the nanoscale
(one-billionth of a meter), where novel physical and chemical properties
arise. The researchers use a technology called Surface-Enhanced Raman
Scattering (SERS), a powerful analytical tool prized for its extreme
sensitivity in obtaining molecular signals that can be used to identify
chemicals. To determine the identity of a particular IV medication,
researchers shine laser light onto a nanostructured gold surface that
contains millions of tiny "nano-domes" that are separated from each
other by as little as 10 nanometers. The nano-domes are incorporated
into the inner surface of IV tubing, where they are exposed to drugs
that are dispersed in liquid. They capture the light scattered from drug
molecules that are in contact with the nano-domes and use SERS to
determine the drug's molecular signature. Finally, they match the
signature to known signatures for the drug in order to confirm the
presence of a specific medication in the IV line.
While other groups have demonstrated excellent nanostructured
surfaces for SERS, those developed by the Cunningham group are unique
because they are inexpensively produced on flexible plastic surfaces by a
replica molding process with nanometer scale accuracy.
Early data show that the Cunningham group's system can identify
medications including morphine, methadone, phenobarbital, the sedative
promethazine, and mitoxantrone, which is used to treat multiple
sclerosis. The system is extremely sensitive: it can detect drugs in
amounts 100 times lower than the clinically delivered drug
concentrations commonly used. So far, the researchers have also shown
their system can sense a two-drug combination, which has its own unique
signature.
The next step is further evaluation for combinations of up to ten
drugs being delivered at the same time. Computer algorithms are also
being developed to automatically interpret the SERS spectra, and
Cunningham's team reports that the system is now being evaluated for
possible commercialization.
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