Multi-wavelength reflectance pulse oximetry

The performance of current reflectance pulse oximeters is hindered by poor signal-to-noise ratio. To overcome this problem a new reflectance oximeter has been developed with a sensor which consists of three LEDs and two continuous photodetector rings placed equidistant from the center of the LEDs. In addition, ultra low noise electronics and adaptive algorithm assure improved performance. A validation study was performed on 10 healthy volunteers. Sensors were placed on several sites and measurements were compared to reference arterial blood samples. During the study progressive hypoxemia was induced by lowering the inspired oxygen concentration (FiO2) to 10%, followed by a recovery phase. Twelve blood samples were taken during each cycle, yielding a total of 120 measured data points. Data from randomly selected 5 subjects was used for calibration and subsequently tested on the other 5 subjects. Results proved to be well within clinically acceptable boundaries for all 3 sampling sites with high correlation (R2 > 0.9) and SD around 2%. In conclusion, a new 3 wavelength reflectance pulse oximeter with unique sensor geometry and improved algorithms provides enhanced performance and is less susceptible to poor signal to noise conditions when compared to existing reflectance oximetry systems.