Toumaz Technology has started clinical trials of what it is calling a “digital plaster”.
It is in effect a wireless body monitor that can continuously monitor multiple vital signs, including temperature, heart rate and respiration.
The trial, which is being conducted by a clinical research team at Imperial College London, is needed to verify that the physiological data acquired by the digital plaster system within a clinical setting in a hospital is equivalent to that acquired using current monitoring systems.
The Sensium digital plaster is based on Toumaz’s AMx semiconductor IP platform, which uses low-power wireless hardware and protocols designed specifically for medical body area networks and non-intrusive physiological monitoring.
The Oxfordshire-based firm specialises in low-power CMOS design, which it implements in the AMx system-on-chip devices used in the digital plaster.
The patented technology provides tightly-coupled digital control of a reconfigurable sub-threshold CMOS analogue chain. As a result, the chip can send 50kbit/s continuously at 1V for 2.5mA.
Each chip has six sensor inputs, which are register-configurable in electrical characteristics to suit sensors including: EEG pick-ups, accelerometers, thermometers, or amperometric (blood glucose) sensors.
Toumaz Technology co-founder Keith Errey says the system will now go through a year of clinical trials in the UK and the US. “I expect the first complete systems to be ready for deployment early next year,” he says.
As with any hospital-based medical system, it is the acceptance of the technology both by the medical standards bodies and by the hospitals themselves that is crucial.
“We have had to create mountains of paperwork defining the device and its functions,” says Errey. “Just as important is the ease with which the technology fits in to the workflow of the nursing staff.”
One hurdle that seems to have been overcome is any previous reluctance to deploy wireless systems in hospitals. “The blanket fear [of wireless] has gone,” says Errey.
Inevitably a lot of attention is focused on the reliability of the radio system and its immunity to interference.
Wireless standards are currently being discussed for wireless personal area networks (WPANs) as part of the IEEE802.15.6 working group.
“When we began development there were no radio standards in this area, so we designed the system from the ground up and we developed a proprietary radio protocol specifically for low-power wireless interfaces,” says Errey.
Body-worn monitors transmit data via the firm’s power-optimised wireless operating and networking system, called Nano Sensor Protocol (NSP).
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The trial is being conducted in three phases, an initial phase with non-patient volunteers followed by two patient study groups: patients recovering from surgery and patients with specific medical conditions in the general wards.
The study, which is being funded by healthcare group CareFusion, is being conducted at St Mary’s Hospital, which is part of Imperial College Healthcare NHS Trust. Initial results are expected by the end of December this year.
“This technology has the potential to improve the capturing of patient’s vital signs within all areas of the hospital,” says Dr Stephen Brett, a consultant in intensive care medicine at Imperial College Healthcare NHS Trust. “This raises the possibility of technology improving hospital safety systems and enhancing the efficiency of adding vital sign data to patient records.”
Brett adds, “This is a very significant step on the path towards pervasive deployment of Sensium-enabled monitoring devices across a range of healthcare settings.”
Errey predicts that within five years hospitals will be routinely wirelessly monitoring patients.
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A commercial version of the wireless monitor called the Sensium Life Pebble, which monitors ECG and heart rate, has recently been awarded a CE mark and is now available in the EU.
“But the Holy Grail will be moving more medical care out of the hospital and into the home, and new types of commercially available wireless monitors will help to make this happen,” says Errey.