Assessment of a Bioimpedance Analog Front-End for Blood Pulse Wave Detection

In this paper, an analog front-end, commonly used for wearable respiration monitoring has been assessed to evaluate its capability of detecting the systolic peak times. Such times are useful for the evaluation of pulse wave velocity and then blood pressure. For the purpose of the analysis, bioimpedance signals have been acquired simultaneously with ECG, using different frequencies and magnitudes for the bioimpedance driving current. Afterward, the R-to-R time intervals from the ECG and the time intervals between consecutive systolic peaks from the bioimpedance signal have been extracted. The delay values, obtained evaluating the difference between R-to-R time intervals and time intervals obtained from the bioimpedance signal, confirm the possibility of using the considered front-end for the determination of the systolic peak times. Despite that, the measured systolic peak times are drastically affected by motion artifacts, thus requiring their compensation, which makes the proposed system suitable for wearable applications.