Contactless sensors detect developing pressure ulcers

The contactless system, developed by Irish researchers, focuses on detecting tissue blood flow — or perfusion — which when restricted can lead to ulcers.

Currently there are methods to detect pressure at the interface between skin and supporting surfaces, but this only provides a proxy for perfusion.

Perfusion itself can be measured using bulky apparatus such as ultrasound, plethysmography or electromagnetic flowmetry, but these too have drawbacks — as project collaborator Dr Sonja Hermann of Trinity College Dublin explained.

‘You can only measure by lifting the limb or the part you’re interested in off the surface, so there’s no really direct measurement of what’s going on when people are lying or sitting down.

‘Also, by using these methods — for example, with the ultrasound head — you actually apply pressure onto the skin and by doing so you’re changing the environment you’re trying to measure.’

The team’s solution was to use a commercially available thin-film ferroelectret sensor — a material that shows similar behaviour to piezoceramics by generating a current upon mechanic stress.