May 1999


By Fred Henning

Recently, we completed the installation of the first "Wireless LAN" segment at ABMC. This was a system set up in the Emergency Department area, which will allow the Admitting Department personnel to enter information into the AlexIS system from anywhere within ER. The information can be from the patient, the patient's family or paramedics. The faster the patient is properly registered, the faster and easier it is to place orders and receive results for that patient. For administration, this also means that all of the charges are captured. (See definitions at the end of the article.)

Wireless technology is advancing very rapidly, and some companies have determined that it is less expensive to equip all of their PCs as Wireless, and not install LAN wiring to every cubical, etc. Wireless connections are being made available at airports and hotels so that traveling employees have access to their e-mail, etc.

The bandwidth, or the number of individual bits (one/zero) per second, for wireless networks ranges from 2 million bits/sec. for a standard system to the 44 million bits/sec. of a proposed Motorola system. For comparison, today's MODEM is rated at 56 thousand bits/sec. The ABMC Network connection to your PC is 10 million bits/sec and the Fiber Optic network that connects the concentrator access points at the various locations on campus is rated at 100 million bits/sec. or 100 megabits/sec. In operational terms, the 56k MODEM can deliver about 4 AlexIS screens per second. The wireless segments can deliver 50 screens per second, the LAN to your PC at 250 screens per second and the Fiber Optic network backbone at 2500 screens per second. Remember that this performances is shared by multiple users on each segment.

Our ER Wireless LAN uses 'off the shelf' RF devices. The portable devices is a Fujitsu 'Tablet' with a commercial RF device built in. The 'Access Points' are standard units which connect to the LAN as if they were a PC. Each Access Point has a capacity of about 2 megabits/sec as compared to the standard PC connection of 10 megabits/sec. There are several levels of security inherent in the radio system we are using, including the fact that the actual frequency of the transmission is continually changing.

There are two Access Points located in the ceiling within the ER area. The two units allow overlapping coverage so that admitting personnel can go to any space within ER, from the Ambulance Entrance to the Fast Track area without loosing their connection to ALEXIS.

Each Access Point has the ability to support about 15 users of the ALEXIS system. The more users, the slower the response would be. If the device were used for Word Processing or other Network intensive applications the number of users should be less because the response time would be greater. The Access Points are monitored and controlled via a Browser view over our Intranet.

There have been some examples of wireless technology saving significant dollars, particularly in teaching hospitals. The concept is to have any orders from a physician making rounds, immediately entered into the HIS. Placing orders for test, drugs, treatments, etc. at the beginning of the day and having a RF device available to the physician all day, is the critical element. The plan of care for a patient can be modified one or more times in the same day and not wait for the next day before a physician see a result, order changes in medication or order another test.

In order for something like this to occur, many Access Points need to be installed throughout the Medical Center. If a comprehensive wireless environment existed, it could be used for applications besides admitting such as nursing, maintenance, transportation, etc.

Some of the key factors in the success of a wireless system is its ability to provide complete coverage. There needs to be an ample quantity of devices for users and the ability to use electronic signatures. (to authenticate orders, results, etc.) The HIS applications must be user friendly when accessed via a tablet or similar hand held RF device. Another element would be the ability to quickly gain approval from the patient's HMO or Insurance company, if required.

The Jesuits stressed – define your terms.

Access Point - For RF systems this is the little 'black box' with an antenna that provides the connection between the wireless device and the network

HIS - Hospital Information System – our ALEXIS system

LAN - Local Area Network - the wires that connect all of the computers throughout the Medical Center, Niehoff, The Woodlands complex, ABHS, HR, etc.

RF - Radio Frequency

Tablet - A tablet is like a Laptop except that there is no keyboard. A tablet has a keyboard that is visualized on the screen and you touch or point at the keys.

WAN - Wide Area Network - the telephone data circuits that connect the various offices and facilities that we cannot connect directly (eg. 500 Park, Occupational Health offices in Bensenville, Elk Grove and Hanover Park, Saint Alexis Medical Center, etc.).

Wireless LAN - In most cases, this is an ability to have small two-way radio devices inside of a computer that communicate with other transmitter/receiver devices, which themselves, are connected to the LAN, as opposed to having network wiring to each computer