RFID vs. USID for real-time tracking of patients, staff and equipment in the hospital setting

image "In a controlled nonclinical trial setting, RFID technology is capable of inducing potentially hazardous incidents in medical devices. Implementation of RFID in the ICU and other similar health care environments should require on-site EMI tests in addition to updated international standards".

So concludes a study published in the June 25th edition of the Journal of the American Medical Association.  In the study, incidents of electromagnetic interference with medical equipment were far more common with passive 868-MHz chips than active 125 kHz RFID systems.  The median distance at which all RFID incidents occurred was 30 cm with a considerable range up to 600 cm.  41 medical devices (IV pumps, anesthesia machines, monitors, defibrillators, etc.) were tested using both chips.  The results included a total of 34 incidents of reproducible electromagnetic interference, 22 classified as hazardous and 2 as significant and 10 as light.

The results of this study are cause for concern and may prompt some hospitals to seek alternatives to RFID for real-time tracking of equipment or staff especially in critical care areas of the hospital.  One such alternative was brought to my attention during a recent visit to hospitals in Norway.  At the grand opening of the European Center for Health Innovation in Oslo, I met briefly with Ragnor Bo, CEO of Sonitor.


Sonitor is a physician-founded company that has pioneered the use of ultrasound in an indoor positioning system that can automatically track precisely, by room, the real-time location of moveable equipment and people in complex indoor environments.  Mr. Bo handed me one of the company's patient wrist bands (pictured).  The bar-coded band has a light-weight ultrasound tag.  The tag is housed in aimage disposable outer case that also contains a small battery that powers the device.  Similar tags and receivers can be used to precisely pinpoint the location of equipment or personnel within a room or even focused sub-zones of  room.   USID, as the technology is sometimes called, is much better than RFID for room-level location because ultrasound waves, unlike radio frequency energy, don't go through walls or floors.  The tags are also being applied in scenarios that enable proximity log-on to computers or other equipment.


A detailed review of USID imageis out of scope for this Blog.  However, you can learn much more by visiting Sonitor's web site.  They also have a very nice animation that illustrates why USID is better than RFID for precise room location tracking.  I suspect the article in JAMA will only accelerate Sonitor's success in the marketplace; success that has already placed the technology in 27 hospitals,  23 of these in the United States.

Bill Crounse, MD   Senior Director, Worldwide Health    Microsoft Corporation

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