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Wire You Waiting?

October 1, 1998
by Edmund X. DeJesus
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Wireless LAN technology is coming of age. More rugged mobile devices, longer battery life, quicker return on investment and product improvements driven by increased vendor competition are making wireless an attractive technology for healthcare.

Wireless LAN technology is the best match for healthcare since bandaids met skinned knees. Wireless improves flexibility, mobility and speed. These translate into better allocation of resources, more accurate and useful data, an improved bottom line and better quality of care for patients.

Wireless LAN technology involves sending and receiving data without using cables--usually by radio frequencies (RF), sometimes with infrared (IR). The data flows between healthcare enterprise computer networks and client devices that include mobile (and stationary) computers, medical monitoring devices, beepers and pagers, mobile telephones and other gadgets. Sounds dull, just like electricity sounds dull: It’s what you do with wireless technology that makes all the difference.

For example, wireless can link LANs in separate buildings on a geographically dispersed healthcare campus. Wireless bridging replaces cables between contiguous buildings and eliminates costly T-1 links between distant (up to 25 miles) buildings. Your savings on thousands-per-month T-1 rentals will pay for the transceivers on each building in a few months--big and rapid return on investment here.

Wireless can link desktops to LANs without running cable. Without being tethered to the LAN, wireless medical monitoring devices (such as cardiac monitors from Marquette Medical Systems, Annapolis, Md.) can transmit data to the LAN from wherever the patient is--even as they move within the facility. Patient records can have up-to-the-nanosecond information for more accurate data, more rapid decisions, more timely care and more efficient use of resources.

Doctors and nurses can update patient conditions at bedside. This means, first, that the paperwork gets done--no interruptions, end-of-shift confusion or delays. Second, no "double documentation"--first to paper chart, then to computer system--so less wasted time and fewer opportunities for error. The same personnel can care for more patients, more efficiently.

Roaming healthcare workers (respiratory therapists, anesthesiologists, and so forth) can find their patients in the facility more easily. They can download past patient conditions and upload new information from bedside.

Up-to-the-moment checks of patient condition and the latest physician instructions can mean faster, more certain and more accurate medication dispensing. The legal folks like that.

Push and pull modes
Wireless technology from companies like Data Critical Corp., Oklahoma City, can intercept alerts from medical monitoring devices and notify the right person immediately. (These systems have Class 3 certification for use in life-threatening situations.) As Brad Harlow, vice president and general manager of Data Critical indicates, this alert notification can happen in "push" or "pull" modes.

With "push," the system pushes the alert out to a special pager, notifying the nurse in charge. The nurse can see an actual picture of EKG and other graphical information, not only text data. Currently, someone has to constantly monitor these devices from a central station, then when an alert occurs they must either find and notify the nurse in charge, or find someone else--who may know a little about the patient. Wireless means fewer workers needed to monitor, faster response time, clearer information and improved quality of care. With such real-time and accurate notification, the nurse can conceivably monitor more patients.

With "pull," the user can pull the information off an intranet Web site from anywhere on earth, as they need it. They can even phone into the facility remotely and review the latest patient information, viewing graphical as well as text data on special telephones. This lets personnel handle more patients, at more facilities, than before.

One system including wireless technology at Maimonides Medical Center in Brooklyn, N.Y., reported advantages including: fewer duplicate medical tests (reducing costs); swifter arrival of routine medications at patient areas; decrease in problem medication and medication discrepancies; lower re-admission rate; reduced patient length of stay; greater capacity for servicing new patients; and improved overall patient satisfaction.

Radio waves
How does wireless work? It’s basically the same principles in your car radio, applied to computer networking. Traditional LANs send data around as electrical signals over wires. But with wireless, stationary "access points" turn LAN data into radio signals and back again. Client devices--laptops, monitoring equipment, pagers and so forth--communicate by radio with these access points, sending and receiving data.

(Infrared is another wireless technology, but since it requires line-of-sight between sender and receiver, it can’t penetrate walls. Radio can. Still, radio won’t penetrate some places either--X-ray rooms and elevator shafts, for example. That’s why you do a "site survey" before installing your system, to place access points to achieve optimal coverage. The range of each access point is several hundred feet (indoors), often enough to cover a single building.)

There are two technical schemes for using radio frequency wireless. Frequency-hopping uses up to 83 different channels, each channel about 1 MHz wide, to compensate for interference. If some equipment--or, more likely, another mobile user--is hogging one of the frequencies, the signal moves to other unused ones and the data flows.