Detección de las frecuencias cardiaca y respiratoria mediante una báscula electrónica

Abstract

A technique for heart and respiratory rate detection using a common electronic weighing scale is proposed. For heart rate detection, the system senses force variations related to the blood accelerations in the aorta. Because respiration modulates that force signal, we can extract the respiratory rate from it. We have applied our method on three different weighing scales whose static and dynamic characteristics were first estimated by a mechanical pulse test. Their sensitivities were from 4 μV/N to 15 μV/N, and their frequency response was broad enough for heart and respiratory rate estimation. For sensing the low force variations (about 240 mN), we designed an amplifier with an overall gain about 75 × 103. The signal-to-noise ratio (SNR) of the main peaks of the pulse signal detected was up to 60 dB, which is large enough for heart rate estimation by simple signal processing methods. Respiratory rate was estimated using frequency domain analysis. The technique was tested on 16 volunteers, wearing footwear and without any additional electrodes/sensors attached to their bodies. The error was ± 0.58 beats/minute for heart rate and ± 1.40 breaths/minute for respiratory rate. © Springer-Verlag Berlin Heidelberg 2007.