Reflective Photoplethysmography Acquisition Platform With Monitoring Modules and Noninvasive Blood Pressure Calculation

Abstract

Modularity is one of the most important aspects of the continuous development of a system. With a modular platform, it is possible to scale the functionalities, adding more features or keeping just the needed ones. A very robust and effective solution for the real-time monitoring problem is an automotive monitoring system whose architecture will be used as the base for a modular photoplethysmography (PPG) acquisition platform. The PPG acquisition platform uses the reflective configuration on the wrist for u-health applications to allow the medical data management of an individual anytime and anywhere. The acquisition platform is equipped with LED voltage control to capture a wave morphology without any interference from skin color, thickness of the fat layer, or stiffness from the subject’s artery walls. This article also provides a technique to obtain blood pressure (BP) in a noninvasive way, based only on the PPG signal with an initial calibration. We also study a technique to obtain the BP parameter, also with PPG and without calibration from an auxiliary device. Our results proved the success of the platform in capturing noninvasive BP calculation in real time, achieving the tolerance errors allowed by the Association for the Advancement of Medical Instrumentation (AAMI). The BP calculation without calibration by an auxiliary device showed promising results, but further studies are needed. Main contributions are the development of a modular human monitoring system based on PPG; improvements on the existing BP calculation algorithm based on PPG; and development of a BP estimation algorithm based on PPG, without calibration from an external device.