Continuous blood oxygen estimation using PPG based on VMD

Abstract

Existing photoplethysmography(PPG) signal is extremely susceptible to interference from baseline drift, and the training interval of traditional algorithms is basically fixed between 80% and 100%, which leads to the low accuracy of blood oxygen detection, especially in patients with severe hypoxemia. Based on the PPG acquisition system developed by ourselves, we use moving average filtering and variable mode decomposition(VMD) to remove high-frequency and baseline drift interference, and use the 30%-100% SpO2 data interval of the Fluke ProSim8 vital signs simulator as the SpO2 algorithm guarantee. Finally, the paper proposed a continuous blood oxygen saturation measurement algorithm based on VMD. The final experimental results show that in the five types of patient data of the simulator, high-precision measurement can be ensured in the normal SpO2 range and in the low SpO2 or even ultra-low SpO2 range; at the same time, the sensitivity of the algorithm to SpO2 is better than that of the reference oximeter. The response speed is faster; finally, in the process of detecting simulated apnea, compared with the reference oximeter, the error of the blood oxygen saturation in the stable interval is ±1, the error of the lowest SpO2 is ±3, and the calculated consistency of the blood oxygen reduction duration reaches 89.10%.