Monitoring of vital signs, that is heart rate and breathing rate, is often limited to acute cases in a hospital environment because it is invasive. To monitor heart rate, electrodes have to be placed on the chest, limiting the movement of the patient, which is a burden, but this method is quite reliable. On the other hand, monitoring of the breathing rate is done indirectly by optically measuring oxygen content in blood, which involves a device attached to a finger or earlobe; the big disadvantage is that this method is not very reliable as blood oxygen content may stay at normal levels even in case of respiratory distress.
The IICT of the HEIG-VD uses a low power radar technology to detect movements of the chest, which are then separated into signals for cardiac and respiratory rhythms. A device sends low power radio waves (similar to those generated by the keyfobs used to unlock car doors) through the chest and detects the tiny signals reflected back by the moving biological tissues, like the heartbeat and the movements of the thorax induced by breathing. The device consists of a small electronic module, and a flat antenna, which can be embedded into a hospital bed mattress. That way, even non acute patients can be monitored in a non-invasive way when they are in their bed.
With this technology, premature babies could be monitored contactless, avoiding the bruises provoked by electrodes placed on their fragile skin. The device could built-in the cocoon at a relatively low cost.
This non-contact and non-invasive way of monitoring vital signs opens new possibilities outside of the hospital domain. The care homes could use it so that their guests’ health can be better monitored, allowing quicker assistance in case of heart or respiratory distress. Similarly, the targeted low cost of the device will make it affordable to enhance the safety of fragile persons staying at home, like elders or persons suffering of epilepsy.
What is special about the project?
The use of low power radar technology is a breakthrough in the domain of vital signs monitoring, enabling non-contact monitoring. GRS is supporting it because of its potential, and because a practical demonstrator will be built and tested in a hospital environment, at CHUV. Industrial companies have already shown a lot of interest in investing in this technology, but on the condition of seeing a working demonstrator, this is where GRS helps decisively. An NGO have also expressed their interest in applying this low cost sensor technology in cocoons for premature babies.
First prototype, built with low-cost components, showed good results, in particular a good sensitivity to respiratory movements. This allowed raising the interest of Elite SA, a Swiss mattress manufacturer, for this technology. Elite SA manufactures mattresses in Switzerland and markets them in an innovative way, billing their use by the night, using wireless sensors embedded in the mattresses.
To expand towards medical markets, Elite SA are already working with ETHZ on a project for a bed adjusting its position to relieve sleep apnea. The MoViS technology, as a reliable breath rate sensor included in the mattress, is part of a CTI project awarded to HEIG-VD and Elite SA in fall 2013. This important step will allow Elite to gain a strong market advantage towards the markets of bedding for hospitals and care homes, allowing continuous monitoring of patients during their sleep.
Epilepsy is a serious health problem, and as MoViS technology is very sensitive for non-contact monitoring of movements, beds will be equipped at the Institution Lavigny, an institution specialised in the treatment of epileptic patients. The non-contact and non-invasive method will complement the «electrode helmets» used to monitor the patients, an expensive and un-practical way to monitor the patients’ sleep. This will allow alerting the personal of the onset of a crisis, as well as allowing a better evaluation of the effects of medication.
Persons involved in the project
Pascal Coeudevez, project manager, pascal.
Dominique Bovey, technical project manager, dominique.
Partners at CHUV
Last update to this project presentation 17.10.2018