Theoretical developments and clinical experiments of measuring blood flow volume (BFV) at arteriovenous fistula (AVF) using a photoplethysmography (PPG) sensor

Abstract

A new theoretical developments of measuring blood flow volume at arteriovenous fistula (AVF) using a photoplethysmography (PPG) sensor is presented in this work. The mathematical equation is derived under the practical perspective, aiming at applying to small-size, portable, inexpensive and easy-to-use PPG sensor, in order to replace bulky, expensive Doppler machines which is the commonly used instruments for accessing AVF noninvasively nowadays. Furthermore, a new, portable and wireless PPG sensor with ambient light compensation and motion artifact detection, is designed for performing clinical validation of the proposed equation. After neural network calibration with the gold standard, dilution concentration sensor, the experiment result reveals that the PPG sensors implementing the proposed equation successfully achieve much higher correlation (R2 = 0.8064) and much lower error (RMSE = 171.68 ml/min, MAPE = 15.84%) compared to the commercial Doppler machine and other previous works.