Non-invasive Optical Method For Measuring Hemoglobin Oxyen Saturation In Tissue Using Vis-NIR Spectroscopy

Hemoglobin oxygen saturation refers to the pecentage of oxygenated hemoglobin in the total hemoglobin account of the blood. Tissue blood oxygen saturation, which reflects the oxygen content of the local tissue, indicates the weighted average of the hemoglobin oxygen saturation in all of the microvessels of the local tissue. In clinical practice, non-invasive, continous, fast monitoring the hemoglobin oxygen saturation of human tissue has very important significance. After summarizing the current detection methods for hemoglobin oxygen saturation as well as the principle and devolopment status of spectrum analysis technology, a non-invasive method based on Vis-NIR spectroscopy is proposed for measuring the homoglobin oxygen saturation according to the optical properties of human tissue and the advantages of spectrum analysis technology. The main works of this paper are as follows:(1) According to the absorbtion properties of oxygenated hemoglobin and deoxygenated hemoglobin at 200-1000nm band, a non-invasive method based on Vis-NIR spectroscopy was proposed for measuring the homoglobin oxygen saturation. Hemoglobin oxygen saturation can be predicted by means of data processing and modeling.(2) An experimental system based on hemoglobin oxygenation model was established and the system parameters for experiments were furthermore adjusted to suitable values. The hemoglobin oxygen saturation obtained by the developed Vis-NIRS method was calibrated on the hemoglobin oxygenation mode and its effective factors were further analyzed. The results of these experiments indicate the developed regression model of hemoglobin oxygen saturation could accurately predict the values of the hemoglobin oxygen saturation in hemoglobin solution.(3) Apply the proposed method to measuring hemoglobin oxygen saturation of human blood. An experimental system based on erythrocyte oxygenation model was established and its system parameters for experiments were modified to suitable values. The regression model of hemoglobin oxygen saturation was built using the developed Vis-NIRS method. The obtained hemoglobin oxygen saturation was calibrated on the blood oxygen saturation and its effective factors effecting on the measurement, such as blood cell concentration, were further analyzed. The results of these experiments show the developed regression model of hemoglobin oxygen saturation could accurately predict the values of the blood oxygen saturation.The prediction results were further analyzed.These experimental results show that the developed Vis-NIRS method could measure the hemoglobin oxygen saturation on hemoglobin oxygenation mode at an error level of less than 6%, furthermore, the blood oxygen saturation of erythrocyte oxygenation model at an error level of less than 10%.In summary, the non-invasive optical method using Vis-NIR spectroscopy could be effectively used to detect the hemoglobin oxygen saturation, therefore, possibly developed into non-invasive device for measuring the hemoglobin oxygen saturation in tissue.