Study On Non-invasive Tissue Oxygen Saturation Monitoring System

Oxygen is the basis for maintaining human life,in hypoxia,metabolic disorders,which in turn lead to cell damage and a series of complications,in the most serious cases will lead to cell death,Therefore,the detection of oxygen content in the blood is an extremely important subject.At present,the monitoring of arterial oxygen saturation and mixed venous oxygen saturation tends to mature,however,the values of arterial oxygen saturation and mixed venous oxygen saturation did not change significantly when local ischemia or internal environment changes caused by hypotension,hypovolemia,embolism,etc.which could not reflect the nociceptive fluctuation of vital signs and the state of local tissue damage,there is no effective monitoring method for tissue oxygen saturation which really reflects the local tissue oxygen saturation,therefore,the non-invasive and rapid tissue oxygen saturation monitoring method has become the focus of research all over the world.Lambert-beer's law has been widely used in the measurement of human heart rate,blood oxygen saturation and hemoglobin concentration,providing a new idea for the monitoring of oxygen saturation in human tissues.The improved lambert-beer law can be applied to anthropometry in a targeted way,which can not only monitor tissue oxygen saturation in a non-invasive manner in real time,provide alarm information in clinical surgery,but also provide valuable measured data for home self-examination and medical research on human body.In this paper,the application of Lambert-Beer's law in the measurement of human blood parameters is studied in depth,and the artificial pulse scheme is proposed to monitor the oxygen saturation of upper limb tissue.A three-light source and two-detector scheme is proposed to measure the oxygen saturation of tissues in any part of the human body in a non-invasive manner.A front-end probe based on DCM06 and DCM08 integrated light source was designed by studying the composition of skin tissue and its optical properties,selecting the proper measuring position and detecting wavelength.Aiming at two kinds of probe structure and combined with three light source and two detector measurement scheme,the related algorithm is realized by MATLAB,the data communication and human-computer interaction are realized by Labview.The 06 system and 08 system for non-invasive monitoring of tissue oxygen saturation are built.The light intensity stability experiment,tissue oxygen saturation credibility test and vein blocking sensitivity test were carried out on 06 system and 08 system,respectively.The results showed that the 08 system was more stable than 06 system for continuous measurement of the same subject.For different subjects,the fluctuation of 06 system is large,which is not suitable for the measurement of tissue oxygen saturation.For different parts of the same individual arm,there is a slight difference in 08 system test results,the difference range is about 0.05.When the system was blocked by vein,the parameters of tissue oxygen changed significantly,and the maximum decrease was 0.25%.The experimental results show that 08 system has high stability and sensitivity.It can continuously and real-time measure the parameters of tissue oxygen saturation,reflect the trend of tissue oxygen change,and can provide an important reference for clinical monitoring of local tissue blood flow.As the integrated light source is used as the light source module,the structure of the light source and the detector have been fixed,and there is still room for improvement in the selection of the distance between the light source and the detector.Therefore,the relationship between the detection light intensity and the distance between the detector and the light source is studied.An integrated probe of light source detector is designed and the optimum distance between the light source and the detector is analyzed.The experimental data show that the same wavelength of light has the same linear region in different individual tissues.When different wavelengths of light are transmitted in the same individual tissue,the linear region is different,so the optimal distance between the light source and the detector must be chosen in the common linear region.A method for measuring the concentration of hemoglobin containing oxygen in human body based on two light sources and four detectors is presented in this paper,which can be used to judge the health status of human body in the later application of tissue oxygen saturation monitoring system.