Concept for a Permanent, Non-Invasive Blood Pressure Measurement in the Ear

In this paper a concept for a new method for a permanent, non-invasive blood pressure measurement in the ear is presented. Currently, blood pressure is measured about once a day and used as the basis for therapy. In order to enable an individual and as mild as possible therapy, a permanent, noninvasive measuring method is required. With every heartbeat, the arteries in the body expand and contract. Blood pressure is the pressure acting on an artery, the higher the pressure the greater the enlargement. If the external auditory canal is closed airtight, the increase and decrease in size of the arteries during the heartbeat causes a change in volume of the closed air chamber and thus a pressure fluctuation within it. The theory is, that these fluctuations represent the blood pressure. In order to prove the theory a prototype was set up, containing a pressure sensor (integrated into an Alpine InEar for airtight sealing), a micro controller and a reference ECG. The sensor was placed airtight in the ear. One test person showed perfect results, in which after each heartbeat in the reference system a corresponding signal was also visible in the ear system. The recorded curve resembles a blood pressure curve, which proves that it is in principle possible to measure blood pressure with such a system. For absolute blood pressure values, the system must be supplemented with further components, this is being researched in the project MikroBO
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funded by the Federal Ministry of Education and Research of Germany.