By Rhea Wessel
Aug. 17, 2009—At
Erlangen University Hospital, in Erlangen, Germany, a consortium that includes the
Fraunhofer Institute for Integrated Circuits (Fraunhofer IIS) will soon carry out a six-month trial of a wireless
sensor network developed to locate medical equipment and monitor the
cold chain for blood.
Fraunhofer IIS' communication networks department developed the system as part of the so-called
OPAL-Health project, which was partly sponsored by the German Federal Ministry of Economics and Technology's
SimoBIT program. SimoBIT supports the development of secure mobile IT applications for midsize companies and public agencies.
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The UHF tag (left) determines its location within the sensor network based on the received signal strength of anchor nodes (right).
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The idea for the project first emerged during discussions held in 2006 between Fraunhofer IIS and industrial partner
Delta T, which operates in the blood-transport sector. In mid-2006, all five project partners met to identify numerous manual processes in blood transport, as well as the tracking and locating of expensive medical equipment that is often the property of a single hospital division but shared by many. The partners designed the system to reduce manual-tracking processes for the machines, and to improve the efficiency of those processes.
If a patient is attached to a portable heart-monitoring device after surgery, for instance, that device—which is the property of the surgical division—is loaned out to the section of the hospital that operates the recovery room when a patient is moved from one area to another, says Ulli Münch, a staff member at the Fraunhofer IIS' Center for Intelligent Objects (ZIO), who is focusing on process optimization and IT integration in the OPAL Health project.
The surgical division, which must account for its expensive medical equipment, runs the risk that the heart-monitoring device might become misplaced within the hospital, or be stolen. To prevent both scenarios from occurring, OPAL-Health's partners sought to monitor the devices remotely. They considered passive
RFID for the job, but ruled out that option since passive RFID tags are
read only when excited by an
interrogator, and the partners wanted constant monitoring. In addition, consortium members were concerned about potential interference that RFID transmissions may cause for sensitive medical equipment.
Another idea, Münch says, was to employ
Wi-Fi tags in conjunction with WLAN technology. However, he adds, few hospitals in Germany are completely outfitted with the Wi-Fi networks. Ultimately, the partners ruled out Wi-Fi tags since they are too large and, due to WLAN standards, use substantial energy, thus leading to a considerably shorter operating life for the Wi-Fi tags.