Researchers at VTT have developed light and wireless sensors capable of capturing respiration rate, oxygen saturation, heart rate, temperature and even an ECG.

If it were possible to monitor the status of patients in hospital care remotely and without interruption, hospital personnel would be made aware of early warning signs of a decline in a person’s condition without delay, and they could react quickly. This would reduce the danger of complications, even potentially fatal ones, and promote recovery, states VTT. For instance, early reaction to changes in vital functions is extremely important in the treatment of coronavirus patients suffering from breathing difficulties.

Wearable sensors

One common target for development at VTT is wearable electronics. Wearable sensors could enable remote monitoring also at home, making it possible to send patients home safely earlier than usual, which would help save health care resources.

“We are developing flexible smart patches that could measure the respiration rate, oxygen saturation, heart rate, and body temperature, for example, and could even take an electrocardiogram (ECG). A smart patch would send the information to a system that would analyse the data and produce follow-up information and send alarms. For example, a patient recovering from surgery could move about freely while measurements are taken, instead of lying in a bed surrounded by wires,” says research team leader Teemu Alajoki of VTT in a press release.

The smart patches have been developed with partners including GE Healthcare.

Based on printed electronics

The structure of a smart patch is based on printed electronics that VTT, has developed for various actors for about twenty years. A pliable, and even stretchable base material moves from one roll to another, as if in a printing press, and the circuitry is printed on it with conductive ink, the researchers state. Separate components, such as integrated circuits, are attached to the base with conductive adhesive, and that can also be done automatically in the roll-to-roll process.

The largest single component on the patch is a button-cell battery, and even that will certainly be replaced in the coming years by a flexible battery, states the scientists.

Interpret monitoring results

VTT is also developing data analytics which would be capable of evaluating changes in the various measurements and to compare them with other measurements from the patient. At best, the system would produce automatic alarms to sound warnings about changes in the patient’s condition, such as cardiac events or blood poisoning, state the researchers.

Reach market within 2-3 years

VTT expects the first smart patches to reach the market within two or three years. The research projects have already taken a step toward solutions at the next level, epidermal electronics that would be even less noticeable for the user than a smart patch, they describe in their press release. Some of the research also targets patches that combine electronic measurement of vital functions with biochemical analysis – for measuring sweat, for example.

Photo: VTT