Technology, K. Kleinberg Research Note 19 March 2003 Wireless Interference in Healthcare Is Real, but Manageable Interference between wireless and electronic devices and medical equipment is a growing problem in healthcare. However, mobile/wireless computing benefits far outweigh the risks, most of which can be effectively managed. Core Topic Healthcare: Healthcare Technologies, Infrastructure and Standards Key Issue How will developments in underlying Information technologies, architecture, standards and regulations affect healthcare organizations' technology strategies? Strategic Planning Assumption By YE03, more than one-half of hospitals will allow doctors to use mobile phones and wireless PDAs that use WLAN technology in at least some areas (0.8 probability). Wireless devices, and just about any form of electronic equipment, have the potential to produce interference with other electronic devices. In healthcare, the possibility that a wireless radio frequency transmitting device, or any device emitting electromagnetic radiation, may unintentionally interfere with sensitive medical equipment is an issue that cannot be ignored. The possibility that such electromagnetic interference (EMI) could cause medical devices to malfunction or fail and potentially cause harm or death to patients has led most healthcare facilities to err on the side of caution. Many facilities, especially with advice from legal counsel, have completely banned the use of cell phones on their premises. Only a few have taken the time to upgrade their signage to reflect a ban on all wireless devices, such as wireless personal digital assistants (PDAs) and some even consider the use of wireless LANs (WLANs) to be too risky to implement. There are few instances in which there is clear evidence that EMI contributed to patient harm, and we are unaware of any clearly documented cases of EMI causing patient death. Only a few hundred entries in the U.S. Food and Drug Administration's (FDA's) Medical Device Reporting (MDR) database are related to EMI. Although there have been several studies on wireless interference and its potential risks (it is relatively easy to demonstrate interference between certain devices), there is a lack of advice and consensus on to how to deal with this problem. As such, what is likely a real, yet small, problem (for example, when compared to medication errors) is effectively a major problem in keeping mobile/wireless computing from advancing in healthcare, especially in acute-care settings. In "Mobile Phones in Hospitals: Should You or Shouldn't You?" we press for hospitals to relax their ban on cell phones. We provide additional details, advice and references for healthcare organizations (HCOs) attempting to deal with the EMI problem. Gartner Reproduction of this publication in any form without prior written permission is forbidden. The information contained herein has been obtained from sources believed to be reliable. Gartner disclaims all warranties as to the accuracy, completeness or adequacy of such information. Gartner shall have no liability for errors, omissions or inadequacies in the information contained herein or for interpretations thereof. The reader assumes sole responsibility for the selection of these materials to achieve its intended results. The opinions expressed herein are subject to change without notice.
Perhaps the best "evidence" the industry has about the relative safety of cell phones and other wireless transmitters and computing devices within healthcare facilities is that even with a ban on most such devices, they continue to be used with regularity and seemingly with little negative effect. Drivers of ambulances and delivery vehicles park just outside the facilities and chat on their radios, maintenance personnel communicate on their two-way radios, physicians are rarely challenged when they use their cell phones within the facilities, and patients and visitors feign all sorts of excuses for not turning off their mobile phones (for example, "they called me, I didn't call them"). Other types of transmitting and EMI-radiating devices that can be found within healthcare settings are wireless telemetry equipment, nurse call systems, wireless in-house phone systems, two-way pagers, patients' electric razors, two-way radios (including the increasingly common and inexpensive Family Radio Service radios used by consumers), microwave ovens, fluorescent lighting, and various types of WLANs and wireless personal area networks (WPANs). There is also plenty of potential interference that originates outside of the facilities, such as from high-definition television (HDTV) transmitters. With all of this activity in the ether, it is no wonder that these devices occasionally interfere with each other, even when the devices do not operate in the same bandwidth or spectrum. Harmonic and intermodulation or sum and difference interference can occur intermittently and make detection difficult. On a positive note, many interference problems, when they occur, have results that are relatively obvious to the observer (determining the cause of the interference is a different issue). For example, there may be a loss or decrease in communication signal quality or data transmission rate, or in the case of medical equipment, the readings or operations of the devices are clearly out of range. Often, the interference is only fleeting in duration. The real problems occur when the interference causes subtle problems that might go undetected for a long time (weeks, months), or when a medical device is part of a closed-loop system or where human monitoring might not be continually present. Blood warmers, infusion pumps, ventilators and patient monitors are the among the devices that could possibly be affected. Therefore, to improve wireless communications, for patient safety issues and to quell the concerns of lawyers, hunting down EMI and preventing as much of it as possible is a worthy goal. There are several steps that HCOs can take to deal with the problem: 19 March 2003 2
Pay Attention to Medical Device Shielding: Almost all medical equipment in use today has some form of EMI shielding, but there have been different standards over the years. In 1993 and again in 2002, more-stringent standards were introduced by the International Electrotechnical Committee (IEC) and recognized by the FDA; equipment manufactured prior to 1993 is more subject to problems and should be given extra attention (older equipment can also degrade over time and be more susceptible to interference). Steps that can be taken include moving the equipment to a more-shielded location (the HCO would have to determine where that is) or replacing the equipment, which would likely be costly (but probably less expensive than attempting to have the manufacturer update/shield it). More-modern equipment is often designed with increased selectivity of circuitry (the device responds only to a narrow frequency range) and is therefore less prone to interference. In any case, whatever EMI tests the vendors claim the devices have passed will have the most relevance if they can be conducted within the HCO's own environment. Form an EMI Task Force: Many biomedical departments have only limited experience with wireless technology, and less experience with wireless interference. It is unrealistic to expect these busy folks (as well as clinicians and other end users) to accurately report on and locate such problems. HCOs that are serious about addressing EMI should consider investing the time and money to train a select group of employees to become part of an EMI task force. Task-force members would attend conferences, work more explicitly with device manufacturers, be part of standards bodies, share resources with other facilities and participate in other EMI initiatives. Among their tasks would be to perform ad-hoc testing, develop policies, recommend equipment purchases, and develop educational and awareness programs. Hiring or training an individual to manage the group and be responsible for all wireless and electromagnetic spectrum use at the facility (a chief spectrum officer) can help departments make solution choices that minimize interference and maximize throughput. Establish Wireless Zones: Given the difficult, if almost impossible, task of enforcing a wireless ban on cell phones and other wireless devices, care delivery organizations (CDOs) should establish several areas where such use is permissible to limit the areas where "policing" is required. The location of such areas should take into consideration the distance from areas with critical medical equipment and the availability of cell phone coverage (such as the hospital lobby). Areas that are heavily instrumented, such as operating rooms and intensive-care units, would require stricter policies. 19 March 2003 3
Enable Lower-Power Transmissions: For wireless WANs (WWANs), CDOs should consider working with local telecommunications carriers (in a revenue-sharing or other mutually beneficial way) to install minibase stations and augment them with in-building repeaters to improve signal coverage, and therefore lower transmission power requirements (cell phones transmitting digitally will generally use much less power than when forced to drop into analog mode). Enact a One-Meter Rule: Studies have shown that increasing the distance between wireless devices and medical equipment by at least three feet substantially reduces the chance of interference most users will agree to stepping back three feet from sensitive equipment (and nurses will feel more comfortable enforcing such a rule). However, this may not be enough distance for certain types of devices and medical equipment, and this should be considered an imperfect policy that might offer some protection in lieu of a more-complete engineering analysis. Update Telemetry Equipment to Newly Established Frequencies: Older telemetry equipment has interference problems with HDTV (particularly channels 7 and 13 to 51) and will have even more problems with the upcoming allocations for Private Land Mobile Radio. The U.S. Federal Communications Commission (FCC) recently established 608-614 MHz, 1395-1400 MHz and 1427-1432 MHz for healthcare telemetry use. Escape From 2.4 GHz When Practical: 2.4 GHz is part of the Industrial, Scientific and Medical band, but it is shared heavily with many wireless devices and standards. Although several chip manufacturers are working to reduce possible interference between 2.4 GHz systems (such as 802.11b and Bluetooth), an eventual migration to approaches based on the relatively unused 5 GHz band (such as 802.11a) and other bands should be considered to reduce interference and enhance throughput. Become Familiar With Organizations, Regulations, Standards Bodies and EMI Test Protocols: Among the organizations that can help CDOs with EMI issues such as regulations, standards, test protocols and policies are: Institute of Electrical and Electronics Engineers and its C63 Accredited Standards Committee on Electromagnetic Compatibility Association for the Advancement of Medical Instrumentation and Technical Information Report 18:1997 American Society of Healthcare Engineering and its frequency coordination capabilities for the FCC's Wireless Medical Telemetry Service 19 March 2003 4
IEC and its 60601-1-2 standard for electrical medical equipment development The FDA and its Center for Devices and Radiological Health's MDR database (www.fda.gov/cdrh/mdr/) Mobile Healthcare Alliance, which recently held a Summit on Electromagnetic Compatibility in Hospitals and Clinics (www.mohca.com/presentations.php3) and intends to host such meetings in the future Emergency Care Research Institute, which has issued position papers on wireless interference American Medical Association and the recommendations it has adopted from the Council of Scientific Affairs Acronym Key CDO Care delivery organization EMI Electromagnetic interference FCC U.S. Federal Communications Commission FDA U.S. Food and Drug Administration HCO Healthcare organization HDTV High-definition television IEC International Electrotechnical Committee MDR Medical Device Reporting PDA Personal digital assistant WLAN Wireless LAN WPAN Wireless personal area network WWAN Wireless WAN The Telemedicine and Advanced Technology Research Center of the U.S. Army and the EMI testing work being done at Walter Reed Army Medical Center Bottom Line: Electromagnetic interference between electronic transmitting devices and medical equipment is a small, but growing, problem that healthcare organizations (HCOs) should not ignore. Although few facilities will be able to develop their own leading-edge expertise in detecting and reporting such problems, all HCOs should become familiar with and implement best practices as they evolve and are made available from government and relevant associations and institutions. By YE03, more than one-half of hospitals will allow doctors to use mobile phones and wireless personal digital assistants that use wireless LAN technology in at least some areas (0.8 probability). 19 March 2003 5