PPG Signal and application in the medical field

Abstract

The ascent of remote health examination is a burgeoning trend in healthcare, aimed at tackling the challenge of hospital overload and streamlining the process of patient monitoring. To achieve these laudable goals, a device that is both efficient and capable of extracting critical health indicators is of paramount importance. Enter photoplethysmography (PPG) technology - a compact and user-friendly device that offers a wealth of health-related information. PPG is an optical, non-invasive method of measuring changes in blood volume in tissue by illuminating the skin and detecting variations in light absorption caused by blood flow. This technique has a multitude of applications, including the measurement of blood oxygen saturation, the estimation of blood pressure, the assessment of vascular aging, and the detection of arrhythmias. Therefore, it presents a promising avenue in addressing the challenge of hospital overload. This article provides an all-encompassing overview of photoplethysmography (PPG) technology, elucidating the underlying principles and highlighting its noteworthy applications. Specifically, the article expounds on the use of PPG in measuring blood oxygen saturation, estimating blood pressure, assessing vascular aging, and detecting arrhythmias. Despite the advantageous applications of PPG, there are still some issues that need to be addressed, such as the limited availability of PPG data sets in certain populations, the sensitivity of PPG signal to motion and ambient conditions, and a lack of clarity about the nature of PPG which leads to the absence of standard criteria in sampling and interpretation of PPG in its applications. And these issues are also thoroughly discussed in the paper.