Electromagnetic Interference: What You’re Not Hearing About RFID Erik van Lieshout, MD critical care physician (internist-intensivist) head of Mobile Intensive Care Unit Academic Medical Center, University of Amsterdam, the Netherlands
<ul><li>University hospital, referral center </li></ul><ul><li>1002 beds </li></ul><ul><li>5458 employees </li></ul><ul><li>2007: 2033 Science Citation Index papers </li></ul>
<ul><li>RFID applications in health care & RFID pilot in the Academic Medical Center, University of Amsterdam </li></ul><ul><li>RFID safety study on electromagnetic interference in the Journal American Medical Association </li></ul><ul><li>How to move on with RFID in the critical care environment </li></ul>
<ul><li>Identification and location of persons within the operating theatre </li></ul><ul><li>Tracking and tracing of operating theatre equipment </li></ul><ul><li>Tracking and tracing of blood products (including new active RFID tag with temperature monitoring) </li></ul>
Draft Guidance for Industry and FDA Staff Radio-Frequency Wireless Technology in Medical Devices Chapter 5: Risk Management for RF Wireless Medical Devices: General Concepts FDA recommends you manage the risks systematically using risk analysis, risk evaluation, and risk controls.
<ul><li>passive RFID system (OBID, Feig Electronic, Weilburg, Germany) 868-MHz reader (2,4 W) </li></ul><ul><li>active RFID system (Eureka RFID, Avonwood, England) 125-kHz reader (68 x 10E-3 µT at 1 m) & 868 Hz active tag </li></ul><ul><li>41 medical devices (17 different categories: IC-monitor, ventilator, syringe pump, dialysis machine, external pacemaker…) </li></ul><ul><li>American National Standard Institute (ANSI) testprotocol (simulators connected) </li></ul><ul><li>Incidents classified by 5 critical care physicians: hazardous, significant or light </li></ul>
hazardous incident (direct physical influence on a patient by unintended change in equipment function) eg, total stop of syringe pump or incorrect pacing by an external pacemaker significant incident (influence on monitoring with significant level of attention needed causing substantial distraction from patient care) eg, incorrect alarm or inaccurate monitoring of blood pressure light incident (influence on monitoring without significant level of attention needed) eg, disturbed display
<ul><li>Results </li></ul><ul><li>In 41 medical devices 34 EMI incidents : 22 hazardous, 2 significant & 10 light (syringe pump, mechanical ventilator…) </li></ul><ul><li>passive 868 Mhz RFID signal: 26 incidents (in 41 devices = 63% ) active 125 kHz RFID signal: 8 incidents ( 20% ) </li></ul><ul><li>median distance (≠ mean ) : 30 cm [0.1 – 600 cm ] </li></ul>
type of incidents and distances per signal distance (cm) type of incidents per RFID signal median [range] 868 MHz 125 kHz hazardous incidents 25 cm [5-400] 17 H 5 H significant incidents 310 cm [20-600] 1 S 1 S light incidents 45 cm [0,1-600] 8 L 2 L 30 [0,1-600] 26 8
34 incidents (22 hazardous) <ul><li>“ worst case but realistic scenario” (max. output power) </li></ul><ul><li>lack of standards: less RFID readers will save costs </li></ul>
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There needs to be a growing awareness among hospitals that problems can occur," Collins says. "And it is difficult to say if something, such as an RFID system, will interfere with critical care equipment unless you do a study. Hospitals need to do a risk assessment of every wireless device that comes into the hospital, because [the wireless devices] all create a greater noise level in terms of radio frequency waves. You really don't know what to expect until they are tested."
Biomed Instrum Technol. 2008 Nov-Dec;42(6):479-84 Christe e.a. Testing potential interference with RFID usage in the patient care environment No events
<ul><li>How to move on with RFID in </li></ul><ul><li>the critical care environment </li></ul><ul><li>update of international standards </li></ul><ul><li>.. </li></ul>
60601-1-2 edition 3.0, 2007 Medical electrical equipment - Part 1-2: General requirements for basic safety and essential performance - Collateral standard: Electromagnetic compatibility - Requirements and tests ISO/IEC 18000-1:2004 Information technology – RFID for item management ?? Part 15 regulations Jul 2008: Radio Frequency Devices ?? European Telecommunications Standards Institute ETSI EN 301 489-1 ElectroMagnetic Compatibility ??
European Telecommunications Standards Institute & ……
<ul><li>How to move on with RFID in </li></ul><ul><li>the critical care environment </li></ul><ul><li>update of international standards </li></ul><ul><li>in the meantime ??? careful management of the introduction of new wireless communications such as RFID: </li></ul><ul><li>on site testing with RFID and critical care equipment involved </li></ul>
Testing all your critical care equipment involved according to the test protocol Practice for On-site Ad Hoc Test Method for Estimating Radiated Electromagnetic Immunity of Medical Devices to Specific Radio-frequency Transmitters (Standard C63.18, 1997)