| With economic development and scientific progress,the number of domestic medical institutions qualified to carry out ECMO(Extracorporeal Membrane Oxygen)treatment has increased year by year.However,at present,most ECMO equipment depends on imports.In order to achieve independent localization as soon as possible,it is urgent to research and develop independently designed ECMO equipment.The detection of mixed venous oxygen saturation is an important link in the process of extracorporeal membrane oxygenation treatment or transport.The medical staff can timely adjust the emergency treatment strategy according to the change of mixed venous oxygen saturation,and can also use the detection results as the basis for adjusting the operating parameters of extracorporeal membrane oxygenation system.This paper focuses on the real-time monitoring of extracorporeal membrane oxygenation saturation.In this paper,the real-time monitoring method of extracorporeal membrane oxygenation saturation is studied,and a set of oxygen saturation detection devices is designed.Aiming at the traditional invasive and discontinuous detection method of mixed venous oxygen saturation,the detection method proposed in this paper can achieve non-invasive and continuous real-time monitoring.The purpose of this method is to detect the mixed venous oxygen saturation in the circulation pipeline at the input end and output end of the membrane lung,so as to evaluate the oxygen supply level of the patient and judge the operation status of the ECMO system.In terms of theory,according to the optical properties of blood tissue,combined with the photon transport theory,the approximate expression of diffuse reflected light intensity value of strong scattering medium under the condition of uniform infinite radius is derived.The mathematical relationship between diffuse reflected light intensity value of blood tissue and blood oxygen saturation is established by applying Lambert Beer law,and the calculation expression of blood oxygen saturation is obtained.In terms of hardware,the hierarchical structure of the reflective blood oxygen sensor,lower computer controller,and upper computer is used to realize the functions of optical parameter acquisition,blood oxygen saturation calculation,and human-computer interaction.The blood oxygen sensor uses the MAX30102 integrated chip to emit red light and infrared light,and collect the diffuse reflection light intensity value.The lower computer reads the light intensity value data through IIC communication and controls the working mode of the sensor.The upper computer reads the blood oxygen value signal solved by the lower computer through 485 serial communication and can display the blood oxygen saturation monitoring information in real-time through the human-computer interface and store it in the text file.In order to improve the detection accuracy of the blood oxygen sensor and reduce the impact of external environment changes on blood oxygen sensor detection,this paper proposes a compensation method for ambient light interference.The experimental results show that this method can effectively improve the anti-ambient light interference ability of the blood oxygen sensor,and reduce the detection error of the blood oxygen sensor to less than 5%.Through the analysis of the anti-interference experiment,stability and repeatability progress verification experiment,calibration experiment,and simulation monitoring experiment,it is proved that the oxygen saturation detection device designed in this paper has good detection performance,measurement accuracy,dynamic stability and anti-interference ability.At the same time,it also proves the feasibility of the real-time monitoring method of blood oxygen saturation proposed in this paper in the actual medical scene.The research results of this paper provide important guidance for the application of real-time monitoring of mixed venous oxygen saturation in ECMO treatment and promote the development of domestic non-invasive blood oxygen detection medical devices. |
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