Bluetooth TM Approach

Transcription

1 Wireless Networks for Hospitals Bluetooth TM Approach This paper discusses the potential of Hospital Wireless networks. Using Bluetooth wireless technology, Hospital networks can provide rapid access to patient information at the Point Of Care, automated data transfer to and from medical instruments, and asset location and tracking within Hospital wards. Tadlys Ltd 3 Shimon Israeli St. Rishon LeZiyyon, 75654, Israel Tel: (972-3) Fax: (972-3) January 2003 ( TM ) Bluetooth is a trademark owned by the Bluetooth SIG Inc, USA and used by Tadlys under license. -1-

2 Introduction Wireless LAN (WLAN) is a mature technology based on the IEEE standard. The standard extends the wired network to support medium range high data rate wireless applications. Thousands of WLANs are deployed in the US and the EU. Bluetooth is an emerging standard for ad-hoc networking. More than 20 million Bluetooth chipsets have been sold in 2002, a record-high feat. Bluetooth networks support wireless Intranet access, wireless synchronization, remote instrument readout, audio streaming and more. This article discusses the merits of deploying Bluetooth networks in hospitals. Mobile handsets are a crucial component of the wireless network and greatly influence the total cost of ownership. Therefore, the first section discusses handset availability and performance. Hospitals are typically "crammed" with critical medical instrumentation. Exposing sensitive equipment to Electromagnetic Interference must be tightly controlled. This is the topic of our second section. Broadcasting private health information over the air is a major concern for the hospital and is closely administered by Governments. The third section reviews and references techniques for combating privacy and security in the wireless environment. Within hospitals, wireless networks are considered as solutions for several different needs: Rapid access to patient information near the bedside Automated data transfer to and from medical instruments Asset location and tracking within the facility While both WLAN and Bluetooth respond to the first need, Bluetooth alone provides a natural solution for the other two requirements. The last two sections of this article discuss these Bluetooth qualities. -2-

3 Handsets Physician's willingness to accept PDAs for their daily tasks is highly correlated with performance issues such as screen brightness, size, resolution, user friendly input scheme, handwriting recognition, intelligent virtual keyboard and long battery lifetime (taken from the "PDA Initiative Project" at St. Clair hospital in the US). PDA candidates must therefore be state-of-the-art high-end devices. Today, practically all of the recent highend PDA versions incorporate embedded Bluetooth with negligible price effect. Most PDAs on the market can support WLAN only as an add-on card, with related higher costs, size, weight, integration and logistics concerns. Battery power consumption for WLAN is about four times higher than Bluetooth, barely allowing a continuous two hour Physicians round, not to mention a full eight hours shift. Figure 1 portrays some of the new PDAs (as of Jan 2003) from HP, Palm and Fujitsu- Siemens. HP ipaq 3975 pocket pc "Integrated Bluetooth wireless technology" Palm Tungsten T Handheld "Built-in Bluetooth Ready" Fujitsu Siemens - Pocket Loox "Join into a Bluetooth hot spot and browse the web, look for new s and get information." Figure 1 Leading PDAs 2002/3-3-

4 Managing EMI patient-injury risks Critical care medical instruments are not immune to electromagnetic interference. From the Association for the Advancement of Medical Instrumentation (AAMI), Technical Information Report (TIR) 18, "Guidance on Electromagnetic Compatibility of Medical Devices for Clinical/Biomedical Engineers": RF transmitters purchased for use in the facility should have the lowest possible output power rating that can be used to accomplish the intended purpose. WLAN transmitted power is 100 mw for both Access Points and mobile devices. Bluetooth defines three power levels 1 mw, 2.5 mw and 100 mw. Commercial mobile devices emit between mw, Access Points normally operate at a level of 2.5 mw. Figure 2 illustrates this point. WLAN access points exhibit zones of high emission, having a power rating much higher than required to accomplish the intended purpose. Access Point High EMI risk Med EMI risk Low EMI risk Coverage with high power access points WLAN Figure 2 Wireless coverage schemes Coverage with low power access points Bluetooth (*) This article refers explicitly to US Federal regulations; comparable regulations are applied in the EU. -4-

5 Privacy and Security Wireless networks and privacy requirements are in conflict with each other. The Health Insurance Portability and Accountability Act 1996 (HIPAA) Security Rule (2002 draft) enforces: Control of access to protected health information Protecting health information from disclosure to unauthorized individuals Protecting health information from alteration, destruction or loss Conversely, the National Institute of Standards and Technology (NIST) US Department of Commerce, (Draft 2002) "Wireless Network Security , Bluetooth and Handheld Devices" states: " the main source of these risks is that with wireless networks the organization s underlying communications medium, the airwave, is openly exposed to intruders, making it the logical equivalent of placing an Ethernet port in the parking lot." While this report equally treats WLAN and Bluetooth as the two reasonable candidates for wireless networks, each with its own strengths and weaknesses, it does uniquely state operational countermeasures in connection with Bluetooth networks to the fact that: "Using the power control feature appropriately forces any potential adversary to be in relatively close proximity to pose a threat to the Bluetooth network", and also "This spatial distance in effect creates a more secure perimeter.". This point is illustrated in figure 3. High power WLAN access points provide a very convenient access to attackers outside the facility. WLAN spillage Corridor Coverage with high power access points WLAN Access Point High Security risk Low Security risk Figure 3 Ward corridor coverage Coverage with low power access points Bluetooth -5-

6 Asset tracking Both economic and regulatory drivers motivate hospital-based asset tracking. The Health Insurance Portability and Accountability Act 1996 (HIPAA) Security Rule (2002 draft) states a media control policy that governs the receipt and removal of hardware into and out of a facility. Equally important, studies conducted on asset management have demonstrated that on any given day in a typical hospital, 20 to 25 percent of the equipment cannot be accounted for or located, tempting the personnel to order excessive equipment. Bluetooth provides a natural solution for tracking mobile assets. The access points periodically enter a scan mode, each reporting the Bluetooth devices within its area of coverage. Low-resolution systems may be based on one access point per ward, sufficient for asset accountability within that ward. High-resolution systems may provide roomlevel resolution. This point is illustrated in figure 4. Visual or audible indications may alert the operator of abnormal conditions. High resolution Low resolution Figure 4 Asset tracking system Bluetooth mobile asset tracking is based on "RF tags" attached to each asset. Virtually any Bluetooth device may be sufficient for this purpose, whether built-in or commercially available "Dongles" for laptops. Asset tracking can be extended to high-risk patient or staff paging. Personal tracking may be as easy as tracking the Bluetooth enabled personal mobile phone. -6-

7 Automated data transfer The rest of this section contains excerpts from the "Medical Electronics Manufacturing" Journal, Fall While very informative, Tadlys believes that some of the quoted statements slightly over-exaggerate some Bluetooth characteristics. "Combining low-cost, reliable wireless technology with medical instruments and a cohesive data-transfer protocol holds the key to addressing the major issues in patient care Wireless connectivity is a step toward building and developing electronic medical records based on a patient's clinical information gathered over time With multiple wireless technologies available, it may seem difficult to determine which is best suited for collecting medical instrumentation data. Table I presents a simplified explanation for various forms of wireless communication It is quite evident from the Table I that Bluetooth is the optimal wireless technology for transferring data into and out of medical monitors. The cost of deploying Bluetooth-based wireless systems continues to decrease. It is now a viable option for medical equipment manufacturers to include wireless connectivity in their equipment. It is extremely important, however, for manufacturers to use a stable communication standard that is backed by a large number of users and is therefore likely to be supported over a long period. The Bluetooth wireless standard meets these requirements. System Type Technology Range Frequency range Deployment cost Power consumption Level Wide- Area Network Cell phones Thousands of meters Local- Area Network IEEE b Personal- Area Network 100 m 10 m Bluetooth 1.8 GHz 2.4 GHz 2.4 GHz Very high High Low Very high High Low radiation Currently, every major semiconductor manufacturer is building wireless Table I. Comparison of wireless systems. integrated circuits based on the Bluetooth standard Modules have been developed for most common sensors, including blood pressure and pulse measurement devices, pulse oximeters, thermometers, blood glucose units, and weight scales; interface module units for electrocardiographs are in development." of High Medium Low -7-

8 Summary Wireless information improves healthcare delivery, reduces medical errors, saves medical staff time and better manages hospital resources and operations. Multiple wireless technologies are currently available to choose from. The design, site selection, installation, operation and maintenance must all be carefully considered when picking out and purchasing the optimal product. The decision makers must avoid pitfalls such as overly high maintenance costs, obstruction to the proper operation of existing medical equipment and violation of privacy regulations. The organization must also create a supportive, user-friendly environment to receive acceptance of the new system by the medical and administrative staff. This article discussed the benefits of using the emerging Bluetooth technology as a preferred solution for wireless hospitals. Bluetooth, characterized by a low power, low cost technology, provides an excellent fit for the hospital environment. -8-