Research And Design Of Wrist-type Monitoring Device For Signs Parameters Of Wounded Persons

Armored ambulances can effectively improve the efficiency of modern battlefield rescue,and the proportion of investment in the military is gradually increasing.However,the internal space of ambulances is limited,and traditional large-scale medical equipment is not suitable for such monitoring scenes.The miniaturization of various large-scale medical equipment has become a research direction of military medical equipment.Pulse rate,blood oxygen saturation and blood pressure,as the basic vital signs of the human body,are an important basis for the diagnosis and treatment of medical staff.Based on the above background,a wrist-type device is studied and designed for monitoring signs parameters of wounded persons in this thesis.The device collects the human body fingertip photoplethysmographic pulse wave based on the reflective principle,detects blood oxygen saturation and pulse rate;the device collects a pressure pulse wave of a wrist band of a human body based on the principle of oscillometric method,and detects blood pressure;the device has the function of binding the wounded information,automatically detecting the physical parameter,and alarming the abnormal physical parameter;the device screen displays the single sign parameter detection value,and uses the near field communication to transmit the historical detection data to the background terminal for reference by the medical staff.The device is studied and designed from the aspects of physical parameter detection accuracy,device life and portability in this thesis.In the hardware design,the digital signal processing method is used to replace the traditional analog signal processing circuit,and the high integration and low power consumption module is selected to control the device volume and extend the life of the device.In the software algorithm design,the smoothing and polynomial fitting are used to remove the high-frequency noise and baseline drift in the photoplethysmographic pulse wave respectively.According to the characteristics of photoplethysmographic pulse wave,the dynamic peak threshold method is used to locate the main wave peaks and troughs,and the envelope is obtained by the extreme point method;In the wristband pressure pulse wave preprocessing,the optimal method is used to design the filter to separate the wristband static pressure and the oscillating pulse wave signal,and the polynomial fitting is used to remove the baseline pulse drift of the oscillating pulse wave.According to the characteristics of the oscillating pulse wave,the dynamic threshold difference method is used to locate the peak and valley,the double gaussian curve is used to fit the amplitude of the oscillating pulse wave,and the variable amplitude coefficient method is used to determine the blood pressure.The design experiments carry out the performance test and the accuracy test of the signs parameters of the developed wrist device prototype.The size of the wrist body of the wrist device is measured to be 70.29mm×55.80mm×37.25 mm,and the blood oxygen pulse rate acquisition module size is 18.34mm×14.39 mm,which meet the portability requirements;the device life time is estimated to be 6.8 hours,reaching the expected target.The maximum error of blood oxygen saturation detection is ±4%,the maximum error of pulse rate detection is ±5 times/min,The mean error of systolic blood pressure measurement is ±4.92 mmHg,the standard deviation of error is 2.87 mmHg,the mean error of diastolic blood pressure measurement is ±3.91 mmHg,and the standard deviation of error is 2.15 mmHg.The accuracy of physical parameters measurement meets the medical standards.