Low blood oxygen saturation quantification in human arterial and venous circulation

[摘要] ENGLISH ABSTRACT: Conventional pulse oximetry has limited accuracy in measuring blood oxygen saturationin low saturation and perfusion scenarios. This limits the application ofpulse oximetry in patients su ering from peripheral vascular a ictions.A novel pulse oximetry system is presented in this study which proposes solutionsto these low saturation and perfusion issues. The presented system wasdesigned to overcome the low perfusion issues by inducing an arti cial pulse in thedetected photoplethysmograph. A novel arterio-venous hypothesis was formulatedto extract arterial and venous saturation data from this arti cial photoplethysmographusing arterial-to-venous compliance ratios. Sensor wavelengths were selectedto provide high and low saturation accuracy, followed by an in vitro sensor calibrationprocedure. System performance was validated by means of in vivo humanstudies.In vivo results indicate good accuracy for high saturation, with limited accuracyin low saturation scenarios. The arterio-venous hypothesis was validated, indicatingthat venous saturation information can be extracted from the arti cial PPG.Although inconclusive, results indicate that the proposed system might be ableto accurately monitor arterial and venous saturation in severe hypoperfusion scenarioswith recommended hardware and calibration modi cations. It is recommendedthat further studies into the presented system's performance are conducted.

[发布机构] Stellenbosch University