Development of a palpable carotid pulse pressure sensor using electromagnetic induction

This paper proposes a novel non-invasive and palpable measurement sensor for carotid pulse pressure. The unit consists of a pair of coil printed circuit boards, a pair of springs and a sensing plastic chip, with each spring attached between the circuit board and the 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. First, the optimal forces externally applied to the proposed sensor were examined to allow accurate measurement of carotid pulse wave amplitude variations. 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 commercialized pulse wave transducer. The resulting coefficient of correlation between the two carotid waves was 0.9 or more. It was therefore concluded that the proposed sensor enables non-invasive measurement of carotid pulse waves.