Full article reprinted from "The Gray Sheet" - June 30, 2008
Interference from radiofrequency identification (RFID) systems may cause medical device malfunctions, Dutch researchers reported June 25 in the Journal of the American Medical Association.
As part of a research project initiated by the Netherlands' Ministry of Health in May 2006, the investigators conducted more than 100 tests on 41 different medical devices from 22 manufacturers, including B. Braun's Infusomat infusion pump, Medtronic and Biotronik external pacemakers, GE's Marquette MAC 5000 12-lead electrocardiogram device, as well as monitors, anesthesia devices and ventilators.
An RFID system requires radiofrequency tags on products or their packaging and a radio receiver that reads the tag from a short distance. Aside from tracking supplies and shipments in hospitals and warehouses, RFID is a favored method of tracking individual devices under a unique device identification system required under the 2007 FDA Amendments Act and now in development at FDA.
FDA defines electromagnetic interference as a "degradation of the performance of a piece of equipment, transmission channel, or system (such as medical devices) caused by an electromagnetic disturbance."
Researchers, including some at FDA, have begun to study how RFID may interfere with pacemakers and implantable cardioverter defibrillators (1"The Gray Sheet" March 24, 2008, p. 3).
However, "the array of literature that promotes RFID in health care is not accompanied by research on the safety of RFID technology within the health care environment," lead study author Remko van der Togt, VU University Amsterdam, et al., write. In particular, "Electromagnetic interference reports on critical care devices are lacking."
In simulations, the researchers approached the medical device with the RFID equipment to check interference levels at various distances.
Two electromagnetic interference tests were conducted, one using a passive 868-MHz RFID system (no internal power) made by Feig Electronic and another using an active 125-kHz RFID system (internal battery power) from RFID-maker Avonwood. A third test used the active RFID tag without its reader.
A total of 123 tests created 34 reproducible interference "incidents." Twenty-two of the incidents were "hazardous" malfunctions, such as total failure of a syringe or incorrect pacing therapy from an external pacemaker. Two of the incidents were "significant," including interference in an atrial and ventricular electrocardiogram. Ten events were classified as "light," including inappropriate beeps or noises.
The researchers note that the passive RFID signal caused more incidents than the active signal (63% vs. 20% incident rate), as well as more serious events.
The median distance between the RFID equipment and the device during the incidents was 30 cm.
Authors Call For Additional Testing, Standards
RFID systems should be carefully managed in the intensive care unit and other critical care hospital settings, and should require on-site electromagnetic interference tests and updated international RFID standards, the authors conclude.
"It seems that hospitals, regulators and manufacturers certainly have some immediate work to do," added Donald M. Berwick, Institute for Healthcare Improvement, Cambridge, Mass., in a JAMA editorial.
Hospitals should internally monitor for electromagnetic interference problems that staff have not noticed or reported, he suggests. Meanwhile, regulators should determine whether new guidance on the safety of RFID equipment is needed.
Finally, manufacturers should examine how their products interfere with other types of equipment and seek "mitigating designs, such as better shielding for both current and future products," Berwick writes.
- Jessica Bylander
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