Monitoring vital signs

2014-02-04 217

Heart rate, body temperature, blood pressure, breathing…checking these kind of parameters are key if we want to keep abreast of our health status, or if we need to track our performance during sport. Unfortunately, up until now, measuring our vital signs has only been possible with the help of complex, and often cumbersome, machines.

But researchers at CSEM in Neuchatel, Switzerland, have been developing a miniaturisation of these technologies. With their new model, everything is measurable using a simple sensor which monitors the manifold processes associated with physical exertion, both during activity and recovery.

Utilising just two simple contact points we have an almost complete breakdown of someone’s physical status, complete with a medical grade ECG, breathing rate, energy expenditure, running speed and body temperature. Then everything is sent via Bluetooth to a control station.

As Senior Engineer on the project, Josep Sola I Caros explains, the technology is simple but has great potential to expand further: “Our technology consists of one system – which includes sensors, a battery and a computer – and which measures electric and optic signals through the user’s body. In fact, the user only puts the device on his skin. The system injects an electrical current through his heart and lungs. From there we can check heart rhythm, ventilation, how many litres per minute the lungs are breathing…and we are working on developing other measures, such as arterial pressure.”

To build these miniaturised devices engineers use 3-D imagery, spinning the virtual circuits on design platforms in order to develop a model which optimises each aspect of its performance. It is a delicate part of the system’s construction but from images to reality, it doesn’t get any easier. It is impossible to assemble devices so small with your hands so engineers must use a microscope to magnify the tiny electrical circuits and then, with the help of a special machine, place them on the support.

Once the sensor is ready, it can be used in many ways. Mannequins at CSEM headquarters display special triathlon suits, complete with inbuilt sensors, which can be worn during cycling, swimming and running, but which can also monitor the athlete while they sleep.

This, as engineer Alexandros Giannakis explains, is an important parameter, especially in sport: “The biggest challenge in professional sport is recovery monitoring. In order to assess recovery, the best way to do that is by monitoring the sleep of an athlete. Using this technology you can see how many times the athlete moved during the night, you can see the minimum values of, for example, the heart rate, the breathing rate or the body temperature. Basically all the information you would get in a sleep clinic.”

Among the different technologies created in Neuchatel, the one for measuring blood pressure is tested at the University Hospital in Bern. Hypertension is also known as the ‘silent killer’ – it impacts more the one third of European population, and the majority of sufferers don’t even know that they are affected.”

The current technology used to monitor blood pressure over 24 hours demands the patient wear an armband, which inflates every 20 minutes (even during the night) and is notoriously uncomfortable.

But, as Senior Researcher at the University of Bern, Stefano Rimoldi explains, the new technology can significantly improve the situation: “In place of the traditional method, we have this new portable system, which encompasses three captors and which allows us to measure blood pressure continuously. There is none of the swelling of the armband, as with the old method.”

Wearing what is essentially a light vest, the patient can live out his life as normal, with no inconveniences, whatever the hour.