Study of Blood-Pressure Measurement Using Noninvasive Methods

Abstract

The correct diagnosis of high blood pressure is important to avoid cardiovascular diseases. In this work, we propose a low-cost noninvasive blood-pressure measurement unit composed of a photoplethysmograph and an electrocardiograph. It is based on pulse transit time measurement, thus performing nonocclusive measurement. To test the effectiveness of this parameter, a total of five subjects were measured, verifying their effectiveness at all times.

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“…Even though it may seem redundant to have include ECG and PPG in the design, they were included to estimate the blood pressure through pulse transit time (PTT) [7,3]; i. e., the elapsed time for the blood to travel from the heart to the wrist. The respiratory rhythm can also be derived from the ECG or PPG using spectral analysis [5].…”

“…The wearable is based on the Arduino Pro Mini and fulfills the terms of Open Source Hardware. The design includes the same ECG, EDA and ST modules as in [4], and an adapted version of the PPG circuit shown in [7] so that it can operate correctly on the wrist.…”

“…Unlike other wearable devices that use Bluetooth for continuous data transmission, we decided to use the SD card to reduce power consumption and extend the battery lifetime. Since the modules used for phyisiological signals were tested in [4,7], there is no need to conduct a similar analysis in this work. We performed a test for the OpenLog module to check missing data.…”