In-Ear SpO2 Monitoring with a Novel Optoelectronic Sensor for Long-Term Conditions

摘要

In this paper,a system which provides a reflective photoplethysmographic (PPG) measurement with an optoelectronic sensor is presented.To analyze the performance of the system concerning SpO2 measurement,we performed human hypoxia studies.Since individual SpO2 values correlate particularly well with the arterial blood oxygen saturation SaO2,which are obtained by arterial blood gas analysis (BGA),a SpO2 measurement in the human ear seems to be possible.Global calibration turned out to be challenging due to a parallel shift between calibration curves.Therefore,an initial single-pointcalibration at normal oxygen saturation is proposed.However,with an experimental setup it could be demonstrated that hydrostatic blood pressure has more influence on reflective pulse oximetry than expected and could be the main reason for the initial bias in SpO2 measurements with small reflective pulse oximetry sensors.