Effects of autonomic nervous system on the quality of non-invasive blood diagnosis by PPG-based sensor system

Abstract

The collection of photoplethysmography (PPG) signals from optical based sensor probe has been used extensively for the monitoring of heart rate (HR), respiration rate and oxygen saturation (SpO 2 ). Prior research by the Optical Fibre Sensor Research Group has extended the information provided by PPG based devices from monitoring HR and SpO 2 to include total haemoglobin concentration (Hb). Research presented here demonstrates that PPG signals are severely influenced by the autonomic nervous system (ANS) variations induced by physiological events, such as yawning and coughing. Using a finger sensor probe with an embedded accelerometer, further investigation demonstrates that PPG based measurements including HR, SpO 2 and Hb are strongly degraded by ANS both during a) movement of body position and b) physiological variation.

An Experimental Study of the Effects of External Physiological Parameters on the Photoplethysmography Signals in the Context of Local Blood Pressure (Hydrostatic Pressure Changes)

“…PPG sensors can measure spectral absorption of haemoglobin derivatives non-invasively and in real time [1,2,3,4,5,6]. PPG sensor devices normally consist of one or several remote sensor units for signal collection (e.g., finger sensor probe) and a central control unit for processing.…”

“…PPG sensor devices normally consist of one or several remote sensor units for signal collection (e.g., finger sensor probe) and a central control unit for processing. Prior research by some of the authors of this investigation has demonstrated promising application of a custom designed PPG sensor device in monitoring heart rate (HR), oxygen saturation (SpO 2 ) and total haemoglobin concentration (Hb) [3,4]. However, a drawback of this technology has been that the PPG signal is easily affected by motion artifact [5,6,7,8,9,10,11], requiring the subject (patient) to be motionless and lying or sitting down.…”