Development of a palpable carotid pulse pressure sensor using electromagnetic induction

This paper proposes a novel non-invasive palpable sensor for measuring carotid pulse pressure. The unit consists of a sensing plastic chip, a pair of coil printed circuit boards, a pair of springs attached between the circuit board and the plastic chip. The distance between the boards is monitored from the displacement of the springs, and the information is converted into a voltage signal based on electromagnetic induction. In this study, the optimal forces externally applied to the proposed sensor were first examined to allow accurate measurement of carotid pulse wave amplitude variations, and it was found that the force applied when the measured maximum amplitudes of the sensor were obtained yielded the best performance. Next, carotid pulse waves were measured using the sensor with these optimal forces, and the results were compared with carotid pulse pressure values measured using a commercial pulse wave transducer. The coefficients of correlation between the two were 0.9 or more. It was therefore concluded that the proposed sensor enables noninvasive measurement of carotid pulse waves.