Ear-worn sensor could be used to gather patients’ vital signs

A British company hopes to develop an ear-worn sensor to speed up the process of gathering patients’ vital signs.

Such a device could quickly collect information on heart rate, blood oxygenation and body temperature in emergency situations but also provide an easier way of recording blood pressure than the traditional inflatable cuff (sphygmomanometer).

Yorkshire-based iMonSys is leading a £160,000 feasibility study with Hull University and Tritech, co-funded by the Technology Strategy Board, to explore the idea of using infrared sensors positioned on and around the ear to calculate blood pressure.

The company has already produced a wrist-based sensor for the remote monitoring of a patient’s pulse and other vital signs using passive infrared signals rather than the established piezo-electric technology.

Now it plans to adapt the technology into a device that will also enable doctors to quickly measure blood pressure in a non-invasive way and that could be used in emergency situations.

‘The idea came from some research we were doing for the Ministry of Defence [MoD], which wanted something that could be put in an injured soldier’s ear to take vital signs even if they had lost their limbs,’ iMonSys founder Graham Priestly told The Engineer.

‘On the battlefield, there’s usually no way of getting data on an injured soldier’s condition in the first half an hour, which is the most important time. This device could also be used by paramedics on road accident victims to get data easily and quickly.’

After the MoD discontinued the research, Priestly and his partners decided to develop the idea commercially and hope to use the new study to prove the concept of collecting blood-pressure data via ear-mounted infrared sensors.

Priestly declined to disclose the method for calculating the blood pressure but said the ear was a particularly suitable location to take the readings. ‘It’s a very rich area for blood,’ he explained. ‘There are two major arteries and some more vein, and it’s non-invasive.’

One of the challenges will be developing software to do the calculations using the infrared readings, which may also provide a way to determine body hydration. The company is also exploring the idea of using acoustic sensors to collect information.

iMonSys’s wrist monitor, which is known as ‘Verity’ and is scheduled for launch early next year, collects vital-signs information from its infrared sensors and transmits it via Bluetooth to the user’s smartphone.

If it records unusual activity, it will ask the user if there is a problem and if needed can then contact his or her doctor or a family member.

‘Our device does away with other units as patients can use it with their phones, which means they can take it away from their homes,’ said Priestly.