Ultrasound Versus RFID
But the most challenging part was finding a way for precise patient location. "Most people use RFID for tracking like this, but ultrasound is very sensitive to walls, which is important for us," Stair said. "If you use a radio-frequency transmitter and then a bunch of detectors that triangulate where something is, you can detect [the patient] a floor above or below. It cant detect if youre on one side of the wall."The tracking device that Brigham is using comes from a Norway company called Sonitor Technologies. The system places specially-designed microphone detectors throughout rooms and hallways, said Sonitor CEO Terry Aasen. The detectors can detect and identify patient signals from a distance of 100 feet. The signals is at a frequency too high to be heard by humans and is similar to the sonar system used by bats. The signals use MFSK (Multiple Frequency Shift Keying) to differentiate the sounds emitted to identify different patients. The shorter the distance, the more precise the system will be, Aasen said, but 100 feet is a safe distance. "At that length, youre depending on echos and other things in the room," he said. The system can detect whether there is even slight movement from a patient and it responds by sending out a tone that is detected by the nearest microphone. "Within the tag, there is an extremely sensitive motion detector. Movement wakes up the item," Aasen said. Brigham has been testing the system on "healthy volunteers" for about three months with ten of the kits, Stair said. "Right now, we only have [tracking] beacons halfway around the lobby. We can tell if they went to the coffee shop," he said. To read about the RFID hype effect, click here. Stair said it was difficult to project the eventual cost of such a system when deployed. Initial costs include about $800 for each iPAQ (one stays with the patient while others are used by staff to see the monitoring results), $10 for each lead, $30 for each position sensor and about $60 for each of five Wi-Fi access points. "But the cost of putting it all together and creating the homegrown software, that I cant calculate," Stair said, but added that the grant-funded three years of development cost "about a million dollars. Theres a lot of engineering time and a lot of expensive professionals." The ER physician said he saw a particularly effective use for the SMART system when he volunteered in New Orleans to help with Katrina emergency medical care. "They turned the basketball arena at LSU [Louisiana State University] into a field hospital. There were stretchers set all around," he said. The potential of losing track of the many patients flowing in and out of that makeshift medical center was huge, he said. Retail Center Editor Evan Schuman can be reached at Evan_Schuman@ziffdavis.com. Check out eWEEK.coms for the latest news, views and analysis on technologys impact on retail.