Electromagnetic interference may pose hazards to medical equipment

Tag : designed for equipment

"Applications of autoidentification technologies such as radiofrequency identification (RFID) in everyday life include securityaccess cards, electronic toll collection, and antitheft clips inretail clothing. RFID applications in health care have receivedincreasing attention because of the potentially positive effect onpatient safety and also on tracking and tracing of medicalequipment and devices. The current expenditure levels on RFIDsystems within health care in the United States are estimated to beapproximately $90 million per year with 10-year growth projectionsto $2 billion," the authors write.
Possible applications of RFID include drug blister packs, whichcould be marked to prevent drug counterfeiting; and the quality ofblood products being monitored with temperature-sensitive RFIDtags. The decreasing size and cost of RFID tags also permits use insurgical sponges, endoscopic capsules and endotracheal tubes,according to background information in the article. The potentialfor harmful electromagnetic interference (EMI) by electronicanti-theft surveillance systems on implantable pacemakers anddefibrillators is known, but the effect on critical care devices innot certain.
Remko van der Togt, M.Sc., of Vrije University, Amsterdam, theNetherlands, and colleagues conducted a study in a controlled,non-clinical setting to assess and classify incidents ofelectromagnetic interference by RFID on critical care equipment.The tests were performed in a one-bed patient room in an intensivecare unit (ICU) and with no patients present. Electromagneticinterference by two RFID systems (active [with batteries andability to transmit information] and passive [without batteries,information retrieved by RFID reader] was assessed in the proximityof 41 medical devices (in 17 categories, 22 differentmanufacturers). The devices included items such as externalpacemakers, mechanical ventilators, infusion/syringe pumps,dialysis devices, defibrillators, monitors and anesthesia devices.Incidents of EMI were classified according to a critical careadverse events scale as hazardous, significant, or light.
All 41 medical devices were submitted to 3 EMI tests resulting in123 EMI tests. A total of 34 EMI incidents were found; 22 wereclassified as hazardous, 2 as significant, and 10 as light. Thepassive signal induced a higher number of incidents (26 in 41 EMItests; 63 percent), and hazardous incidents (17), compared with theactive signal.
Hazardous incidents included: total switch-off and change in setventilation rate of mechanical ventilators; complete stoppage ofsyringe pumps; malfunction of external pacemakers; completestoppage of renal replacement devices, and interference in theatrial and ventricular electrogram curve read by the pacemakerprogrammer.
The median (midpoint) distance between reader and device at whichall types of incidents occurred was 11.8 inches. Hazardousincidents occurred at a median distance of 9.8 inches.
"The lack of standardization of RFID in health care permitsRFID systems originally designed for logistics to enter the medicalarena on the basis of requirements such as the range at whichmedical tagged items or individuals are to be detected. However,the economic benefits of optimal health care logistics, including asupply chain of RFID-tagged disposables or pharmaceuticals, couldface barriers in the critical care environment. The intensity ofelectronic life-supporting medical devices in this area requirescareful management of the introduction of new wirelesscommunications such as RFID," the authors write.
"Implementation of RFID in the ICU and other similar healthcare environments should require on-site EMI tests in addition toupdated international standards."
Editorial: Taming the Technology Beast
In an accompanying editorial, Donald M. Berwick, M.D., M.P.P.,F.R.C.P., of the Institute for Healthcare Improvement, Cambridge,Mass., writes that this study provides important information.
"From the particular case of RFID and EMI, therefore, emerge 2important lessons. First, design in isolation is risky; even themost seductive technology will interact in the tightly coupledhealth care world in ways physicians and other members of thehealth care team had better understand, or they and their patientsmay pay a dear price. Second, no matter how good the design, in theend the battle for high safety and reliability in health care isnever won. Safety is not a condition, it is a process. It can onlyemerge continually in a culture that is alert, cooperative,transparent, and resilient when the unexpected happens, as italways will."
Journal reference : Remko van der Togt; Erik Jan van Lieshout; Reinout Hensbroek; E.Beinat; J. M. Binnekade; P. J. M. Bakker. Electromagnetic Interference From Radio Frequency IdentificationInducing Potentially Hazardous Incidents in Critical Care MedicalEquipment . JAMA , 2008;299(24):2884-2890 [ link ]