Research And Design Of Portable Health Parameter Monitoring System

Battlefield rescue is an important part of modern war,the use of medical armored vehicles can greatly improve the efficiency of rescue,but large-scale medical monitoring equipment can not meet the rapid and flexible characteristics of battlefield rescue,therefore,a portable monitoring equipment suitable for medical armored vehicles is designed to fight injury treatment is of great significance.The portable health parameter monitoring system designed in this thesis can detect and display the three health parameters of human blood oxygen saturation,pulse rate and blood pressure,and provide important basis for medical personnel to determine the treatment plan for the wounded.The portable health parameter monitoring system designed in this thesis collects the photoelectric volume pulse wave of human fingers based on the principle of reflection detection,calculates the blood oxygen saturation by extracting the AC and DC components of the photoplethysmographic pulse wave,and extracts the pulse wave peak point to calculate the pulse rate;detection of blood pressure by oscillometry,and the blood pressure value is calculated by collecting wrist oscillating waves;the data is transmitted by near field communication,which can ensure the stability of data transmission and the requirements of low power consumption of the system.In terms of hardware design,considering the size and usage scenario of the monitoring system,a highly integrated module is selected to optimize the design of the signal acquisition circuit and reduce the size and power consumption of the entire hardware circuit system.In terms of software algorithm design,simple and easy-to-implement signal processing algorithms and feature point extraction algorithms are used to reduce calculation time;mean filtering is used to remove singular points of the photoplethysmographic pulse wave,smoothing filtering is used to remove the high frequency noise of the photoplethysmographic pulse wave,and morphological filtering is used to remove the baseline drift;for the calculation of blood oxygen saturation,differential product method is used to locate the extreme point of the photoplethysmographic pulse wave,and the envelope is obtained by cubic spline interpolation,calculation of blood oxygen value by using the formula of blood oxygen saturation after calibration;select the appropriate preprocessing algorithm to separate the pressure signal and the oscillating wave signal in the cuff,median filtering is used to remove the baseline drift of the oscillating pulse wave,ensure the signal is not distorted,difference product method is used to locate the extreme point of the waveform,and finally the Gauss curve fitting and the variable amplitude coefficient method are used to calculate the blood pressure.In this thesis,a series of experiments are designed to test the portable health parameter monitoring system.In the performance test,the system can complete the collection and processing of blood oxygen signals and blood pressure signals,as well as the calculation of various parameters,the system's battery life is more than 6 hours,reaching the expected index.In the accuracy experiment,the error of blood oxygen saturation detection is within ±3%,the maximum error of pulse rate detection is ±5 times / minute,the average error of systolic pressure is ±4.80 mm Hg,the standard deviation of error is 2.54 mm Hg,and the average error of diastolic pressure is ±3.67 mm Hg,the standard deviation of error is 2.33 mm Hg,and the blood oxygen saturation,pulse rate and blood pressure detection accuracy meet medical standards.