Research On Cerebral Blood Oxygen Monitoring Method Based On NIRS And Preliminary Implementation Of The System

The brain is one of the most important organs of the human body,and the completeness of its functions is the basis for safeguarding human life activities.In recent years,there have been more and more researches on brain function and physiological background,and the monitoring of cerebral blood oxygen saturation is one of the important directions.Cerebral blood oxygen saturation is a physiological parameter that reflects the oxygen supply and blood supply of the human brain tissue,as well as the brain function activity.During the clinical perioperative period,by monitoring the cerebral blood oxygen saturation of the patient,problems such as cerebral ischaemia and hypoxia can be detected and dealt with in time to avoid more serious consequences.Traditional cerebral blood oxygen monitoring methods are mostly invasive or indirect monitoring,which cannot accurately reflect the state of blood supply and oxygen supply to the brain in real time,and the results obtained still have false negatives and false positives.This article analyzes the current clinically commonly used cerebral blood oxygen monitoring methods.Based on their respective advantages and disadvantages,near-infrared spectroscopy(NIRS)is selected as the research method of this article.As a non-invasive,low-cost,easy-to-implement,and high-time resolution brain blood oxygen monitoring technology,NIRS technology has great potential and broad application prospects.The main research work of this article includes:(1)Based on the modified Beer-Lambert law,combined with the physiological structure of the brain and its optical characteristics,the measurement principle of the relative change of cerebral blood oxygen parameters is proposed.On this basis,combined with the characteristics of spatially resolved spectroscopy technology,the principle of measuring the absolute change of cerebral blood oxygen parameters is further proposed to realize continuous real-time monitoring of cerebral blood oxygen saturation,oxygenated hemoglobin concentration and reduced hemoglobin concentration.(2)For the noise sources in the cerebral blood oxygen signal,according to their different characteristics,this paper proposes corresponding de-noising algorithms to improve the signal-to-noise ratio.(3)Based on the measurement principle of the absolute change of cerebral blood oxygen parameters,this paper proposes a corresponding cerebral blood oxygen prediction model,which takes optical density signals of four wavelengths as input,and outputs the corresponding cerebral blood oxygen saturation value after data conversion and processing.In addition,personalized correction coefficients C_ID,K₁ and K₂ are proposed to further improve the accuracy and reliability of the calculation results.(4)On the basis of the non-invasive brain blood oxygen monitoring hardware platform independently developed by the research group,a host computer software system was developed to be used as a human-computer interaction interface for controlling the operation of cerebral blood oxygen monitoring equipment.At the same time,the non-invasive brain blood oxygen monitoring model researched in this topic is used to obtain and display the changes of cerebral blood oxygen waveform and cerebral blood oxygen value in real time.(5)This article designs an in vivo brain blood oxygen monitoring experiment.According to the changes in cerebral perfusion caused by Valsalva action,the changes in the two hemoglobins and the calculated cerebral blood oxygen saturation are observed to preliminarily verify the effectiveness of the brain blood oxygen prediction model in this article.Based on the experimental results,further research plans are proposed.The research done in this article aims to provide a new solution for the application of NIRS technology in clinical cerebral blood oxygen monitoring.The proposed four-wavelength cerebral blood oxygen prediction model is expected to obtain higher precision and more reliable prediction results,and the developed host computer Cerebral blood oxygen monitoring software can provide better human-computer interaction.