INSIDE THE CURRENT ISSUE

August 2008

News

RFID, RTLS companies address signal interference claims in study

When the Journal of the American Medical Association published in late June the results of a study that showed that wireless tracking systems may emit signals that interfere with a variety of medical devices and equipment designed to treat patients safely, reactions were as swift and compelling as the initial study results were controversial.

Almost immediately, key companies in the radiofrequency identification (RFID) and real-time location system (RTLS) technology segments launched into full defensive mode, seeking to clarify misconceptions, correct erroneous assumptions and douse any from-the-hip surefire reactions with a dose of careful planning, common sense and logic.

As a service to our readers, Healthcare Purchasing News invited a variety of RFID and RTLS companies to respond directly to the fundamental question on the minds of healthcare supply chain management professionals today that either are prospective RFID and RTLS users or existing ones: What do we do now? What follows, in their own words, are their answers to this targeted question. For official company and other organization responses to the controversy in general, go to HPN Online.

HPN: For healthcare facilities considering investing in RFID/RTLS technology, how should the recent JAMA study results affect their decision to adopt and implement the technology?

Joseph Costa, vice president, marketing, Aethon Inc.

Healthcare facilities considering RFID/RTLS technology must first understand that all RFID-based asset tracking technology is not alike. The technology implicated in the RFID study published in JAMA was primarily passive RFID systems. Passive RFID readers and portals can emit up to 4 WATTS of power. In comparison, our Aethon Asset Tracking solution uses RFID tags that output only 0.75 mW, that’s less than 1/5000th the power of a passive RFID reader. And Aethon’s RFID readers and portals emit virtually zero power. They only listen for tags.

Another important technical distinction to understand when evaluating RFID technology is the distance from the transmitter. In the JAMA study, medical equipment was one foot from the reader/transmitter. The power of transmitter RF is 1/distance², so the distance from the transmitter makes a big difference. Aethon’s Asset Tracking solution uses only a few readers that are mobile, as they are installed in our TUG, an autonomous mobile robot. TUGs roam the hospital tracking and recovering assets and emit very low power virtually eliminating the possibility of interference. In comparison, other passive or active RFID tag systems require literally hundreds of readers all over the hospital at a much higher infrastructure cost and higher potential for RF interference.

For healthcare facilities, the decision to adopt and implement RFID-based asset tracking technology is still is a sound business decision with considerable cost savings, asset utilization and clinical support benefits. Understanding the power emission specs and infrastructure requirements of the various RFID solutions available will also help to meet their patient safety and wireless interference protection needs.

Jason Howe, CEO, Awarepoint Corp.

The value proposition offered by RTLS in healthcare is significant on many levels – financial, safety, satisfaction. Although this study was referring to non-clinical tests, the implications have a pronounced impact on how RTLS plays in patient care environments. What healthcare administrators must focus on is keeping high-powered transmission devices, as defined in the JAMA study, at a reasonable distance from their critical care assets. In RTLS deployments, however, there are several technology options available that are outside the interference range outlined. Although from a layperson’s perspective, many technologies are lumped into the generic term "RFID," in reality, numerous technology options exist, including ZigBee, Wi-Fi, Ultra-Wide Band, Ultrasound, etc., that do not use RFID in the literal sense.

Awarepoint’s RTLS utilizes 802.15.4 ZigBee mesh networking technology. The Awarepoint solution generates less than 1mW of power (4,000 times less power than standard active and passive RFID readers) and can monitor assets up to 300 times the distance required by alternative technologies.

ZigBee is a protocol specification and industry standard for a type of wireless communications technology generically known as Low-Rate Wireless Personal Area Networks (LR-WPAN). LR-WPAN technology is distinguished by low-cost, low-power wireless devices that self-organize into a short-range wireless communication network to support low throughput applications such as real-time location systems.

To further mitigate interference concerns, the Awarepoint solution operates in the 2.4GHz band. Operating in the Industrial Scientific and Medical (ISM) band allows the Awarepoint solution to coexist with existing wireless technologies that support telemetry, wireless Internet access (Wi-Fi), and patient monitoring (IEEE 802.15.1). Each asset tag and network device optimizes its use of the medium by occupying unused portions of the RF spectrum and by occupying unused time-on-the-air.All Skytron Asset Manager/Awarepoint networks are channel-scan compatible and operate at an average duty cycle less than 1 percent.

Tuomo Rutanen, vice president, business development, Ekahau Inc.

It should affect their decision. Healthcare facilities should look to adopting mainstream standardized technologies that are proven in the hospital environments over years of use. A good example is Wi-Fi. It has been used in the healthcare industry for nearly 10 years and no problems have been reported. Furthermore, more and more Wi-Fi devices are being deployed in hospitals inside clinical equipment, telephones, computers, etc., and for many other uses – not just tracking systems.

Hybrid technologies that use multiple frequencies, e.g., Wi-Fi and Active RFID, may be suitable in the Wi-Fi-only mode, but the active RFID side may pose a risk, especially if it operates in the 125kHz or 868 mHz band as outlined in the study. An FCC approval only allows general operation of the radio equipment; it does not guarantee against EMI in a hospital.

Bryan Christianson, vice president, marketing, Mobile Aspects Inc.

The decision for healthcare facilities to adopt and implement RFID technologies should not be dramatically affected as the technology can bring tremendous value in solving complex operational and clinical issues within the clinical setting. However, the study has brought forth the need for healthcare facilities to include a level of diligence in their evaluation and selection processes to ensure that the highest levels of patient safety and quality are maintained while deploying the RFID technology.

This level of diligence should involve understanding the proximity in which RF will be emitted within a spatial area, the characteristics of that RF emission and the potential for creating electromagnetic interference (EMI) and in turn, identifying medical equipment located within that area that has the potential to be susceptible to EMI. In completing these steps, a preliminary discourse with the RFID technology vendor should occur to have the vendor inform the healthcare facility about any anticipated concerns with EMI and medical equipment performance. In addition, placed into the technology implementation plan should
be an event that includes the performance testing of the medical equipment to ensure EMI is not occurring at levels that jeopardize performance reliability in the medical equipment.

Steve Jackson, Chief Technology Officer, RadarFind Corp.

The JAMA study covered the likely scenario of RFID readers causing anomalous behavior in electronic devices when those devices were brought within close range of the RFID readers. This can happen because of the high energy levels used by RFID systems.

The explanation of why this study actually does not apply to RTLS deployments is an interesting and timely issue. Many lay people equate any radio-based tagging technology with RFID, and this is the root of the confusion. The questions raised by the study results show that it is now time for a comprehensive education effort on the part of industry press and manufacturers. In short, despite the colloquial interchangeability of the terms, RTLS in reality does not infer RFID.

It is absolutely critical to note that real-time location systems do not generally employ RFID technologies. In stark contrast to RFID, RTLS technologies on the market use power levels that are a tiny fraction of those described in the JAMA study. RTLS device power levels simply cannot create enough interfering energy to make a nearby electronic device malfunction.

Paul Tessier, executive vice president and Chief Strategy Officer, Radianse Inc.

Certainly this is not a call to abandon RTLS or even RFID. Even the report’s authors advise against a hard stop on solutions that use RFID. But certainly hospitals should carefully evaluate the safety impact of any technology they are considering. Because Radianse made a choice to focus its real-time location platform exclusively on healthcare, safety and effectiveness have always been top of mind. We have never wavered from that commitment, holding steady through the influx of all-purpose locating systems that converged on healthcare.

Adrian Jennings, Chief Technology Officer, Time Domain Corp.

Healthcare facility operators should not be deterred by the findings of the JAMA study: The study included only a very small subset of the technologies available, and as such does not cast doubt on RFID in general. Any administrator thinking of installing an RFID or RTLS solution, with or without the results of the study, should think very carefully about interference issues and consider the many technologies available.

If tags or readers are to be used in very close proximity to medical devices, then they should be tested first for coexistence. Choices such as ultra wideband, which operates at power levels 10,000 times less than other systems, are designed to blend into the background noise, thereby offering no appreciable interference. Such systems provide an excellent solution for situations where sensitive diagnostic equipment can be adversely affected by higher power systems such as those described in the report.

John Wass, CEO, WaveMark Inc.

The research presented in the recent JAMA study indicates the importance of knowing the details of any proposed deployment. For example, the JAMA study did an excellent job of assessing the behavior of UHF (868 MHz) passive and Low (125 KHz) active RFID technologies in a specific deployment model, in this case implementations using maximal power to increase a far field signal coverage area.

This study brings us back to the differences between evaluating a technology versus a solution. RFID is a technology and is available in many different flavors. By way of example, WaveMark leverages RFID technology to track physician preference items in specialty labs and uses both different technologies and a different deployment model than the ones described in the JAMA article. WaveMark uses the 13.56 MHz frequency in a near field read model (6-10 inches) which allows the solution to operate at less than maximum allowable power levels. Furthermore, the read environment is structured to minimize environmental variables which might otherwise require site specific variations in the deployment approach.

WaveMark recommends that healthcare facilities work closely with prospective vendors to review the details of a proposed implementation to ensure a safe and productive implementation.

For healthcare facilities that already are RFID/RTLS-equipped, how should they react and change their operations in light of the recent JAMA study results?

COSTA: Healthcare facilities currently utilizing RFID/RTLS asset tracking technology should first understand the testing methodologies used in the study published in JAMA and how it compares to their actual practice and perform a risk assessment. Understanding the RF power emission of their exsting RFID system and how their system is logistically deployed are important factors in their assessment.

HOWE: Healthcare facilities that have already deployed traditional RFID systems operating at 125kHz or 863MHz should consider the data set reported in the JAMA study and pay particular attention to the distance between the RFID reader and the asset that is being read.

For hospitals already deployed with the Awarepoint RTLS, the choice of technology is a sound one. The Awarepoint solution generates less than 1mW of power (4,000 times less power than standard active and passive RFID readers) and can monitor assets up to 300 times the distance required by alternative technologies. To further mitigate interference concerns, the Awarepoint solution operates in the 2.4GHz band. Operating in the Industrial Scientific and Medical (ISM) band also allows the Skytron Asset Manager/Awarepoint solution to coexist with existing wireless technologies that support telemetry, wireless Iinternet access (Wi-Fi), and patient monitoring (IEEE 802.15.1). Each asset tag and network device optimizes its use of the medium by occupying unused portions of the RF spectrum and by occupying unused time-on-the-air. All Awarepoint networks are channel-scan compatible and operate at an average duty cycle less than 1 percent.

RUTANEN: If they are operating systems with proprietary technology that leverages either 125 kHz active RFID or 868 passive RFID, they should be concerned and perhaps consider turning these systems off for now or at least use caution around them. If it is RTLS using Wi-Fi there should be no concerns as no issues have been reported, and Wi-Fi uses the 2.4 ghz frequency that has been, for example, used by microwave ovens for decades.

CHRISTIANSON: For healthcare facilities currently using RFID technology, an initial reaction should be one of thoughtfulness and prudence to evaluate the performance and reliability of the medical equipment within proximity of the RF emissions. This can include a survey of medical equipment users to obtain anecdotal evidence of any performance issues, a review of maintenance and service records of the medical equipment, and a more detailed performance evaluation with the assistance of biomedical engineering or other personnel. If any issues are found, the RFID technology vendor should be contacted to begin a dialogue in determining if EMI from the RFID technology is the cause or a contributor to performance issues. As many systems beyond RFID are operating within healthcare facilities today, there could be several potential contributors to EMI.

Beyond the immediate analysis for signs of EMI, if not already in place the organization should develop a policy for clinicians to swiftly communicate any performance issues experienced with the medical equipment. This policy should not only reflect the process of communicating the issues, but should also outline a protocol of investigation, trouble shooting, and removal/replacement of equipment as determined by the functional area responsible for maintenance and operation of the medical equipment.

JACKSON: If a hospital is using RFID, it is likely that the technology is employed as a bar-code alternative and used for inventory control purposes, usually to monitor consumption of consumables. RFID readers that activate passive RFID inventory tags are, by their nature, either short-range devices (less than 1 meter range) using low power emissions, or, they are high-power devices with a longer range (perhaps up to 5 meters). For the latter, a qualified investigation into interference potential is prudent, and that is exactly what the JAMA study correctly indicated. There are professional contract firms that will come on site and perform this type of analysis.

However, if a hospital is using RTLS, it is all but certain that such systems do not employ any RFID technologies, since RFID technologies cannot practically be used to provide RTLS functionality. Because RTLS systems use ultra-low power levels, they are harmless to electronic equipment and people.

Hospitals using RTLS technology are right now scratching their collective heads about the JAMA study, since these facilities have never experienced any equipment malfunctions due to their RTLS deployments. These hospitals can safely continue to leverage their RTLS investment because the constituent RTLS devices operate in a benign manner regarding nearby equipment and personnel.

TESSIER: I think hospitals have every right to expect their vendors to explain and demonstrate safety. A hospital with a Radianse RTLS can be assured that Radianse is different in every way from those systems tested. Radianse does not use an excitation signal – Radianse receivers simply pickup the signal from the tag. Also, Radianse utilizes 433MHz, the same UHF band safely used for decades in medical telemetry systems. The peak power emitted by Radianse system is 200,000 times less than tested system. Finally, the Radianse RTLS has accumulated millions of hours of operation with no reported interference – as expected.

JENNINGS: It should be noted that interference issues will not suddenly start to appear because of the publication of this report. Any facility that is already successfully using an RFID or RTLS solution without interference should not rush to switch it off.

However, the report does caution users that in certain situations, with certain technologies, interference may occur. It is advisable for people to read the full report to understand the circumstances under which interference was seen, and not rely in snippets gleaned from media reports about the findings. By understanding the details of the findings, processes can be updated to avoid those specific circumstances cited as harmful, or different RFID/RTLS technologies sought if process changes are not possible. Many alternative technologies exist, including non-interfering options like ultra wideband.

WASS: For facilities that have already deployed RFID-enabled RTLS solutions, they should review with their vendor the described adverse conditions from the JAMA article and confirm that they do not exist or take steps to prevent these interactions in the future. As with all reports on adverse interactions, it is important to know the details and react to the specific situation within your own facility.

In conclusion, it is important to note that the new technologies under discussion deliver important patient safety benefits as well as logistical efficiencies. The ability to identify a device which is malfunctioning (such as an infusion pump) or that a device sitting in a storeroom has been recalled (such as an implantable) contributes greatly to patient safety. The combination of patient safety and economic benefits suggest that the industry will continue to move forward in this area. The JAMA article is a valuable contribution to understanding some of the parameters of prudent deployment practices which are central to achieving these and many other benefits to come as the industry adopts and leverages these exciting new technologies.

See Having My Say for a related story on bar coding relevance in an RFID world.