WHITE PAPER Digivance ® ICS For Healthcare Applications Digivance ® ICS For Healthcare Applications Wireless in Hospitals – Good or Bad? As you enter most hospitals, it is very likely that you will be greeted with a sign looking something like this: Studies have shown that radiation from cell phones has the potential to interfere with cardiopulmonary monitoring devices, and in some cases may even cause malfunction of patient ventilators 1 . Such evidence would seem to indicate that cell phones constitute a significant risk to patient health and safety, warranting their ban from hospital facilities. But many of the same hospitals that are banning cell phones are, at the same time, bringing more and more wireless equipment into the hospital environment. Wireless Local Area Networks (LANs) are being installed at a rapid rate. The mobile access to medical records provided by wireless LANs is being touted for its benefits to patients, in articles with titles such as: “Wireless LANs: Just What the Doctor Ordered” 2 and “Wireless Is the Healthy Choice” 3 . In addition to network access at the nurse’s station, such wireless systems often include mobile voice handset coverage throughout the building 4 . What is the Difference? So why are wireless LANs being installed at the same time cell phones are being banned? Why can't I use my cell phone when I see hospital personnel roaming the corridors talking on theirs? It’s all a matter of POWER. With wireless LANs and local wireless phone systems, fixed antennas are distributed throughout the building. The distance from a laptop computer or wireless handset to the nearest antenna may be only a hundred feet or less. Such distances can easily be spanned with transmit powers of 20 milliWatts (mW) or less. 1 Tri, Jeffrey L., David L. Hayes, and Rodney P. Severson. “Cellular Phone Interference With External Cardiopulmonary Monitoring Devices”, Mayo Clinic Proceedings, v76, 1/01. 2 Robinson, Teri. “Wireless LANs: Just What the Doctor Ordered”, InternetWeek, 8/24/98. 3 Schick, Shane. “Wireless Is the Healthy Choice”, Computing Canada, 12/1/01. 4 Lee, Chris. “The Wireless Cure”, ZDNet (UK), 9/24/01. For patient safety, the use of cellular phones is not permitted while inside hospital buildings. Page 3 Digivance™ ICS For Healthcare Applications In contrast, a typical cell phone not only has to reach a cell site antenna that may be located a mile or more away, it must first penetrate the steel and concrete shell of the building itself. In order to do this it will likely need to operate at its maximum power level, typically 600 mW. In fact, even though cell phones have the ability to reduce their power in good coverage areas, most studies on the effects of cell phone interference assume that within hospital buildings, the cell phone will generally be operating at its maximum rated power. At the maximum cell phone power of 600 mW, the Mayo study found that “clinically important” interference occurred 7.4% of the time if the phone was within 60 inches of a piece of medical electronics. Actual equipment failure occurred only with one piece of tested equipment, and this occurred only when the 600 mW cell phone was placed within 5-10 cm of a data port on the rear panel of the device 5 . While this may seem like a minimal threat, the healthcare environment mandates erring on the side of safety; hence, the ban on cell phones. At 20 mW, however, the radius of potential interference is reduced from 60 inches to about 11 inches; and the risk of an equipment failure, such as the one noted in this study, becomes almost non-existent. This reduces the risk significantly enough for such low power wireless systems to be considered “hospital safe”. Problems with Cell Phone Bans There are several difficulties with the widely adopted ban on the use of cell phones in hospitals. One big disadvantage of this policy is that it deprives medical workers, as well as patients and their families, of a primary means of communication–in fact the very means of communication that may not only be the most convenient but also the most vital in emergency situations. A second disadvantage is that such a ban requires enforcement. Cell phone use has become prevalent to the point that many people no longer give a second thought as to where they are when they place or take a cell phone call. The aura of acceptability is even further enhanced if visitors see hospital personnel using cell phone-like handsets, not knowing that they may be non-standard units designed for use only with the hospital's internal wireless phone system. The third disadvantage is that such bans are ineffective. Many people do not realize that even when not being used in conversation, cell phones (unless they are completely turned off) continually transmit control information to maintain contact with the nearby base stations. As long as they do not use their phones, most people believe they are complying with the ban. In reality, many hospitals which have instituted such a ban are likely frequented by visitors whose cell phones are continually transmitting signals from within their pockets or purses. Problems with Local Wireless Phone Systems Installing a local wireless phone system gives hospital personnel cordless access at low power. However, this solution is not without its own drawbacks. The local system may require use of special handsets which are not compatible with standard cell phones. This means that hospital personnel need to carry two mobile phones, one for use inside and one for outside the building. Such local systems can be expensive and difficult to integrate with the existing PBX. Handsets, in particular, tend to be more expensive, as they do not benefit from the quantity distribution and service provider subsidies that keep cell phone prices low. In addition, a local wireless phone system provides access for hospital personnel only, not for hospital visitors. It also does nothing to solve the problem of energy being transmitted continually by idle (but still turned on) phones in pockets and purses. The Digivance ™ Solution The Digivance ™ Indoor Coverage Solution (ICS) enables employees and visitors to use their cell phones within hospital buildings while minimizing the risk of interference to medical equipment. It does this by distributing cell phone coverage throughout the building through a series of low power Digital Remote Units (DRUs), each transmitting a maximum of +13 dBm (20 mW) of power. Placing low power DRUs throughout the building means that cell phones will only have to transmit as far as an antenna which is, at most, a few hundred feet rather than miles away. In addition, its signals do not need to penetrate through the steel outer frame of the building. This means that cell phones used within the building no longer need to operate at maximum power. Instead, the power control algorithm inherent in all cell phone systems will reduce the cell phone power to typically tens of milliWatts or less. The reduction in power takes place automatically, without any action required by the cell phone user. Even the phones forgotten in pockets and purses will automatically reduce their power simply by being in the vicinity of a Digivance DRU. As an added benefit, this reduced power results in lower current drain, thereby maximizing battery life, at the same time interference is being minimized. Web Site: www.adc.com From North America, Call Toll Free: 1-800-366-3891 • Outside of North America: +1-952-938-8080 Fax: +1-952-917-3237 • For a listing of ADC’s global sales office locations, please refer to our Web site. ADC Telecommunications, Inc., P.O. Box 1101, Minneapolis, Minnesota USA 55440-1101 Specifications published here are current as of the date of publication of this document. Because we are continuously improving our products, ADC reserves the right to change specifications without prior notice. At any time, you may verify product specifications by contacting our headquarters office in Minneapolis. ADC Telecommunications, Inc. views its patent portfolio as an important corporate asset and vigorously enforces its patents. Products or features contained herein may be covered by one or more U.S. or foreign patents. An Equal Opportunity Employer 103148AE 7/06 Revision © 2006 ADC Telecommunications, Inc. All Rights Reserved WHITE PAPER Targeted Coverage By careful placement of the remote units, wireless coverage can be customized to meet the requirements of any facility. Coverage can be added to difficult areas, such as basements, tunnels, and shielded rooms, by installing DRUs in those locations. In addition, antenna placement can be used to independently control the amount of power reduction in different sections of the building. Sparsely placed antennas will result in a wider range of handset powers, which may be acceptable in public areas of the building; more closely spaced antennas will provide tighter power control in particularly sensitive areas, such as critical care units. The Digivance Advantage Digivance ICS uses advanced technology that sets it apart from all other indoor coverage systems. It is the only such system that distributes its wireless coverage over digital fiber. Fiber, unlike coax or twisted pair wiring, is completely immune to reception or generation of electromagnetic interference, making it easy to install alongside other wiring without fear of noise or crosstalk. Digital optics means that either single or multimode fiber can be used without degrading signal quality, allowing the installer to take advantage of any unused fiber that may already be in place within the building. Digital fiber also minimizes the noise level on the path back to the base station. Keeping the noise level on this path low is essential to minimizing cell phone output power, and only the digital optics of the Digivance system can offer the lowest possible noise level, regardless of the length of fiber. Digital optics also enables complete flexibility of installation topology and number of antennas. Coverage areas can be expanded by adding, or even daisy-chaining, Digital Expansion Units (DEUs). Multiple areas, floors, or even multiple buildings can be covered, with uniform “digital quality” signals delivered to even the most remote antenna. Summary: The Benefits of Installing a Digivance ICS Hospital System • Potential for interference with hospital equipment is minimized, or even eliminated, by minimizing handset transmit power. • The need to enforce a cell phone ban is eliminated. • Power reduction applies to all phones, even those “forgotten” in pockets and purses. • Hospital employees are given the convenience of maintaining mobile communications, without requiring separate handsets for indoor and outdoor use. • Hospital visitors are able to stay in communication with others. • Battery life for portables is increased. • The digital fiber technology of Digivance ensures optimum reliability, ease of maintenance, and simplicity of installation for trouble-free and worry-free service. • Digital fiber technology guarantees immunity from optical path loss. Every antenna in the system, from the closest to the farthest, will provide the same high quality signal–enabling uniform coverage throughout the largest buildings or even multi-building campuses. In short, the need for safe, high quality, and trouble-free wireless communications in the hospital environment has been met with ADC’s unique indoor coverage solution–the digital advantage of Digivance. This hospital is equipped with Digivance ™ coverage. Feel free to use your cell phones in this facility. . WHITE PAPER Digivance ® ICS For Healthcare Applications Digivance ® ICS For Healthcare Applications Wireless in Hospitals – Good or. 9/24/01. For patient safety, the use of cellular phones is not permitted while inside hospital buildings. Page 3 Digivance™ ICS For Healthcare Applications