Design of a new reflectance pulse oximeter by obtaining the optimal source-detector space

Pulse oximetry is an important medical monitoring technique. Interest in the use of reflectance mode of pulse oximeters has been grown for monitoring the arterial oxygen saturation (SaO2). The design sensor has an effective role in improvement of reflective pulse oximeters performance. In this study, the light propagation in tissue has been analyzed for development of reflection pulse oximetry. After analyzing theory, the optimal source-detector space was determined and a revision on SaO2 formulation calculated with Lambert-Beer law performed to reduce the errors. The new type of reflectance pulse oximeter was designed based on the theory calculation and then calibrated by in vivo experiments. The detecting signal have least dependence on changes in scattering properties of the tissue for obtained optimal space. One of the advantages of this design is reduction of influence of unconscious movement. In this novel design, calibration and validation experimental results show the repeatability potential and accuracy of the system.