Keeping track of patients

Philips has developed a new sys-tem for wireless digital monitoring of hospital patients in a collaboration with Cambridge Consultants in the UK.

The Intellivue telemetry system works by maintaining a radio signal between the patient, a bedside monitor and a central station, which can be accessed by doctors. It gives data on patients’ blood pressure and heart readings wherever they are in the hospital.

Existing telemetry systems restrict patients only to those areas of the hospital with radio cover, as the signal is lost if they move out of range. However, because the Intellivue system is cellular-based, like mobile phones, it allows patients to move freely around the hospital as it automatically switches between channels to maintain contact.

Cambridge Consultants provided the radio architecture to allow the system to maintain its signal while avoiding any interference from other radio signals in the area. The system operates in the 1.4GHz Wireless Medical Telemetry Service (WMTS) band. This band is used solely in the US for medical telemetry in hospitals, a policy which Andrew Diston, senior vice president of Cambridge Consultants US, said the UK should adopt.

‘The benefits of having a band dedicated to solely to medical telemetry is that telemetric devices can be operated safely and without any risk at all,’ he said. ‘This is something that we should be doing in the UK.’

The WMTS band is narrow, and the channels within the band are both narrow and very close together. This meant the company had to devise a way of getting all of the data into one channel.

‘We really had to squeeze the data down to fit it all in. We had to modify the DECT (Digital Enhanced Cordless Communications) to fit the spectral requirement. I believe it is the first time it has been done in this way,’ Diston said.

The Intellivue system also uses ‘Smart-Hopping’ technology to avoid interference. ‘Smart-Hopping’, which has been developed by Philips, automatically dodges interference on the channel and seeks out the strongest possible signal. One of the advantages of the technology is its compatibility with hospital systems. It can work alongside Philips’ digital telemetry systems, wireless bedside and ambulance monitors, as well as a hospital’s own WiFi system.