BBI Contributing Writer

SAN JOSE, California – The creation of the new Wireless Medical Telemetry Spectrum (WMTS) band took effect with action by the Federal Communications Commission (FCC) in early June and holds considerable promise for the future. As discussed in Part 1 of our report from the annual meeting of the Association for the Advancement of Medical Instrumentation (AAMI; Arlington, Virginia) in last month's issue of BBI, the WMTS band is part of a host of changes affecting the entire U.S. patient telemetry market. While the future may hold all manner of promise for use of the new band by the medical industry, its immediate impact will be less than thundering.

Many vendors, including Agilent Technologies (Palo Alto, California), GE Medical (Waukesha, Wisconsin) and others, already use other frequencies for medical devices, such as the ISM bands, and have no plans to discontinue them and move everything into the WMTS band.

Two other companies – Criticare Systems (also Waukesha) with its MPT II and Protocol Systems (Beaverton, Oregon) with its new Micropaq – have started using the ISM band for patient-worn monitoring (not transmitters). These are both interesting products that the market may well now turn to adopting. They are not just patient-worn transmitters, but rather are patient-worn monitors (PWMs). All the major vendors offer patient-worn transmitters – the familiar, battery-operated, wireless transmitter that sends ECG waveforms (and perhaps SpO₂) signals in one direction to a remote central station. However, patient transmitters do not include waveform displays, vital signs, high/low alarm enunciation or signal processing. Patient-worn monitors are smaller and more portable versions of portable bedside monitors – small enough so a patient can wear them. A PWM supports a bidirectional radio (not just a transmitter) and includes a waveform and vital signs display. It processes high and low alarm locally without depending on a remote central station.

Because they include commercial ISM radio technology, these devices cost about the same as the older patient-worn transmitters but are a lot more flexible. Without a doubt, these newer devices have the potential to displace patient-worn transmitters, just as the original portable monitors displaced the inflexible, AC line-operated bedside monitors a decade ago. These devices will bring about a fundamental change or, more accurately, work with a fundamental change that already is occurring in the hospital as it considers how to transform itself into the technologically advanced "hospital of the future."

Both Criticare and Protocol have chosen to use the 2.4 GHz ISM band, and both use exactly the same radio vendor, Symbol Technologies (Holtsville, New York). Because PWMs are so self-contained, they inherently reduce concerns about interference or momentary transmission that exist with older patient-worn transmitters (since these devices do not do their own processing, waveform display and alarm processing without the central station). Indeed, the new Micropaq PWM continues to monitor on the patient if it encounters a null within the antenna range or intentionally moves outside of the antenna range (such as when a patient goes to radiology for tests), and then "catches up," sending trends and data collected when it comes back within range.

Central stations become mobile

Protocol took the notion a step further. In its hospital-of-the-future vision, a fixed location central station becomes just another convenient display location, rather than a central, mission-control area to be constantly manned and monitored. This is in stark contrast to Vitalcom's (Tustin, California) vision of the future. Protocol Systems also has shown a work-in-progress of a nurse portable central station device, which allows the central station to become mobile and go with the nurse. The pocket PC, which is the base device for this portable central station, also is made by Symbol Technologies and runs Microsoft (Redmond, Washington) Windows CE and Palm OS. This rugged, 7"x3" PC is perfect for medical applications, as it is designed to withstand drops to the floor without damage. It operates for more than one shift before requiring recharging. Because portable central stations communicate on the same ISM bands as the patient-worn monitor, they support transmission of voice and medical data, and have a built-in bar code reader and IR bidirectional link. This scanner also is useful for scanning patient ID bracelets, bar codes of drugs being administered at the point of care, and communicating with other staff, as well as displaying the vital signs of other patients a nurse wants to look in on, or who go into an alarm condition.

The flexibility of a nurse having a highly portable device that can do all of these things saves the nurse from having to return to a remote, fixed central station to respond to alarms is appealing, and also avoids having the responsibility for surveillance of patients removed from nurses and placed with monitoring technicians at some other unit within or remote from the hospital. The interesting thing about these new devices is that they offer features and benefits to hospitals that do not exist in any of the major vendors' patient-worn transmitters available in the WMTS band. If either of these companies can do a good job educating the market and differentiating themselves from the rest of the suppliers, they will have a potential for rapid and dramatic growth. Of the two companies, Protocol, particularly now that it will be part of Welch Allyn (Skaneateles Falls, New York), seems poised to take the most advantage of this opportunity.

Convergence of medical, commercial wireless

Both Criticare and Protocol are placing their bets on the ISM band and industry standards and ultimately on technological convergence of commercially available wireless technologies, as opposed to proprietary, medical industry technologies. Over the last 15 years, the medical monitoring vertical market has historically benefitted from and rapidly adopted commercial technologies at the point where they fit the medical use. This occurred for simple economic reasons. Because the number of units that can be sold in the commercial market is several orders of magnitude larger than the number of units that can be sold in the medical vertical market, use of commercial/ consumer products reduced costs dramatically. The same engineering expenditures are required to make a product, whether it will be used by a few tens of thousands of users or millions of users. However, as the number of users goes up, the price paid by the user comes down. Over the last three decades, the adoption of standard commercial technology, and its displacement of technology proprietary to the medical vertical market, becomes quite clear. Commercial wireless technology may be the next technology to be adopted by the medical sector.

Medical adopts commercial operating systems

Many readers may remember a time before we had "no fade" displays, and viewing several seconds of waveforms was nearly impossible. The medical industry's initial, proprietary answer was memory displays. Then pixel-mapped CRTs and LCDs became available in the consumer market, and became low-priced. They were quickly adopted and appeared in medical devices of all sorts, as they were much cheaper than any medical supplier could produce. The same thing happened with microprocessors. As Intel and Motorola became the dominant suppliers of these devices in the commercial market, medical devices were designed around one or the other of these microprocessors.

Mennen Medical's (Clarence, New York) new products use QNX, some Marquette Eagle products use a variation of Unix, Agilent Technologies uses Windows NT at its Viridia central station and Protocol Systems uses Solaris – all commercial operating systems. None writes their own operating system for monitors or work stations, and everyone has adopted some operating system to use.

Battery technology is the same story. The medical sector uses commercial battery technology, not proprietary technology. It also uses commercial wired LAN technology, as every major supplier except Agilent Technologies has adopted IEEE-802.3 ethernet, using TCP/IP signaling. Only Agilent maintains a proprietary LAN technology, which may be to its disadvantage. Its Serial Distribution Network (SDN) has a data rate of only 2 Mbps, compared to 100 Mbps for fast Ethernet. It also uses proprietary cable, which makes installations more expensive. In its newest products, Agilent is now changing to Ethernet as well.

Telecommunication is changing to the Internet , away from standard telephone lines. Telephone companies such as AT&T are buying up companies like Net2Phone, that are offering to route telephone calls over the Internet. AT&T and British Telecom paid $1.4 billion for a 32% share of Net2Phone because telephone calls in the future will be using the Internet.

The medical sector also is embracing the Internet. At the Healthcare Information and Management Systems Society conference earlier this year, it was difficult to find one company that was not showing or developing a "web-enabled" means of accessing their various medical information system products. Several monitoring companies – including Agilent Technologies, Spacelabs, GE Marquette, Siemens and Protocol Systems – have developed web-enabled portals into their patient monitoring systems, allowing doctors to access patient information using a laptop or Palm Pilot running a web browser.

Hardware displaced by software algorithms

As technology has advanced, medical devices have increasingly become software and front-end signal conditioned, running on commercial computer components. The medical sector's core competence has been limited to algorithms, signal processing, and systems integration.

That brings us back to the question: Is the medical sector ready to adopt commercial Wireless LAN technology, or will it continue with proprietary, expensive, inflexible wireless designs in the new WMTS band, or perhaps do a little of both?

This is now being played out. The choice between the proprietary transmitters available in the new WMTS band and the commercial ISM transmitters is a choice between expensive proprietary technology and inexpensive, commercially standardized technology. The first medical vendor to ship WMTS transmitters was Spacelabs, in December 1999. Since then, has shipped several hundred units. Symbol Technologies announced a new, hand-held dCPU with an ISM 2.4 GHz radio at the same time. Symbol is experiencing double-digit revenue growth because of the demand for its radios, but neither Spacelabs nor any other medical monitoring supplier is experiencing such growth.

Symbol's radios (which are bidirectional and support voice and data transmission simultaneously) cost less to the end user than any WMTS radio presently available from any manufacturer. Because of the large market and widespread use of ISM radios, there are many suppliers (companies like Proxim, Breezecom and dozens of others) of such radios, access points and antennas to choose from. There is an industry consortium, published standards for interoperability, a testing program and certification seal of compatibility, and many diagnostic and network management tools useful for troubleshooting these standardized networks when difficulties arise for ISM, but almost none for WMTS band devices. WMTS vendors may never offer such tools, because it costs a lot to develop them, and the market for them would be small.

So we come back to the original question: Is Protocol's and Criticare Systems' bet that the medical sector will embrace commercial wireless LANs and move away from proprietary technology a good one? If history is any teacher, it will be, in time. Whether this is the moment for that transition is more difficult to predict. Obviously, both Protocol and Criticare feel it is. Protocol was right in its timing on portable monitors. Perhaps this is déjà vue.