The University of South Australia is developing a range of smart bed sensors that are small enough to be embedded in hospital bed mattresses to help reduce the incidence of pressure injuries.

While wearables, cameras and weight-based sensors are commonly used, the developers say the unobtrusive sensors can detect when a patient turns over, leaves their bed, or has not moved for some time.

UniSA researchers led by Stephen Warren-Smith have developed a proof of concept of a multimode optical fibre (MMF) sensor array that can be used to detect and image movement on a bed.

The researchers say the optical fibre sensors are embedded in the same space as a person, but not on them physically.

They can be attached to the upper surface of a mattress to monitor movement and record heart and respiratory rates, and nurses can be remotely alerted if a patient has not moved within a couple of hours, prompting them to adjust the patient’s position.

Dr Warren-Smith said the technology could help to relieve the burden on hospital staff having to constantly monitor patients for pressure sores.

“Each year, thousands of older Australians in hospitals and nursing homes experience pressure injuries, or ulcers, which take a long time to heal and can be fatal,” Dr Warren-Smith said.

“At the very least these injuries can cause severe pain, disrupt sleep, affect their mood as well as their rehabilitation, mobility and quality of life.”

Hospitals currently use weight-based sensors or cameras installed in the room to monitor patients, but both have limitations, he said.

“Existing weight-based hospital sensors cannot predict when a patient leaves the bed until their feet touch the floor, leaving little time for nursing staff to respond in the event of a fall. Also, there are privacy issues with camera-based technology.”

According to UniSA, optical fibre sensors are sensitive enough to record heart and respiration rates and can detect whether a person is in the bed, even if they remain stationary for long periods.

“Respiration rates are often the first sign that a patient is deteriorating. This normally requires devices to be attached to the patient, either on the chest, as a mask on the face, or ventilator. These can be restrictive and sometimes inappropriate in an aged care setting.

“Monitoring vital signs continuously, unobtrusively and cheaply via the mattress-embedded sensors is a far better solution for both patient and nurse.”

The research has been published in the Journal of Biomedical Optics.