At Samaritan Medical Center (SMC) in Watertown, N.Y., we needed to continuously monitor patients' vital signs as we moved them from the emergency department (ED) to radiology. To maintain the monitoring signals, we planned to implement wireless technology, but we had to balance competing data demands across a finite bandwidth within our hospital. Several years of research and development led us to achieve a Wi-Fi solution that prioritizes critical monitoring data from the ED while continuing to service other departments in the hospital.

Traditionally, patient monitoring has required its own separate, dedicated network to guarantee security and performance. Now, using a virtual local area network (VLAN) within our existing network, we can put critical patient monitoring data in the "fast lane," ahead of administrative applications.

In 1999, we purchased a wired monitoring system for the ED from a business unit of Siemens Medical Solutions that later became part of Drager Medical of Telford, Pa. However, our long-term plan was to improve upon our previous wireless monitoring system and replace the wired system with wireless. Our previous wireless system had used radio frequency (RF) transmission, and although the antennae were correctly positioned throughout the ED and radiology, the lead walls in the diagnostic area caused complete loss of signal when moving patients into radiology rooms for X-rays and scans. The signal was also subject to cellular phone and electrical equipment interference problems.

When Drager Medical came to install the wireless technology for ED monitoring at Samaritan in 2003, they realized that there would be duplication of the wireless access points that the hospital's IT department was already in the process of installing to support the hospital information system (HIS). Everyone at SMC agreed that the wireless initiative had to happen, but installing two wireless network infrastructures would cause major problems.

Unlike RF antennae, which only receive signals from devices, wireless access points both receive and send information from and to each device. With two access points in the same area, patient monitors or laptops would not be able to lock on to just one. The device would try to "talk" to both access points, bouncing from one to the other, and never be able to transmit its data.

Too Much Traffic

Our IT steering committee, which included senior management and physicians, had to carefully balance different interests throughout the hospital, blending both biomedical and information technologies, and always keeping in mind the bottom line goals of improving patient care while maximizing the use of our existing infrastructure.

The key challenge that we needed to address was that there were too many data applications or "vehicles" potentially trying to use the hospital's "information highway" (the network). Since we knew we could not simply add new access points to successfully go wireless, the various departments would have to share the bandwidth. Over the course of 2003-2004, through research into standards-based wireless technology and application data traffic management solutions, we determined that patient monitoring and other HIS applications at Samaritan could co-exist. Because this technological feat had never been accomplished before, it took a full six months to get these systems to work together.