Study On A Ring-type Ambulatory Blood Pressure Measurement And System Implementation

Blood pressure is the vascular blood pressure in the vessel wall, and it's a reflection of the primary parameters of the human cardiovascular system will be of great importance in the clinical diagnosis of the disease. Blood pressure could reflect a real-time health of the body, but it's also very vulnerable to external factors such as exercise, sleep and mental activities of the interference, which affect the measurement results of measuring blood pressure. And in recent years, the emergence of a ambulatory blood pressure measurement(ABPM) system that can be good to avoid problems caused by casual blood pressure generated. ABPM is an interval of 15 to 30 minutes medical equipment can be automatic and continuous monitoring of blood pressure changes in the 24-hour monitoring, and then treatment patients receive the blood pressure curve of 24 hours and offer medical analysis to determine the current status of the patient's blood pressure.Compared to the conventional electronic blood pressure monitor, ABPM has a very great breakthrough. But through our research, we found it necessary to design a ring-type of ABPM system, because: the accuracy of the problem: the oscillometric method has principle defects, so that the accuracy of ABPM should be improved; Measurement: traditional blood pressure measurement using the cuff to measure the blood pressure, this approach will produce discomfort will affect the patient sleep at night, increase blood pressure measurement error; measuring time: existing measurement time is generally 40~50s, and long measurement time more likely to have outside interference when measuring. In order to solve existing dynamic sphygmomanometer defects, this paper developed a ring-type ambulatory blood pressure measurement system. The main contents are as follows:(1) Improve the method of pulse wave measurement and blood pressure calculation. By studying the analysis and comparison of a variety of curve fitting algorithms, this paper will choice Gaussian algorithm to fit the peaks of pulse wave envelope. By using improved varying amplitude coefficient method, the scale factor can be determined by Gaussian fitting curve, which also can improve the measurement of individuality.(2) Provide a method to reconstruction finger arterial blood pressure to brachial artery blood pressure. First, using the above method to obtain patient finger arterial blood pressure; and then return-to-flow(RTF) method for selecting the optimum pressure gradient distortion calibration methods were conducting calibration pulse wave distortion and pressure gradient distortion; and finally, the reconstruction the brachial artery blood pressure to comparative verification with medical standards.(3) Improve the measurement. This article select a fast method of measuring blood pressure when pneumatic booster, so we should focus on solving the problem of that pump will affect the measurement accuracy. But finally, this measurement approach will greatly reduce measurement time.(4) Improve the ring-type ambulatory blood pressure monitoring system design. By increasing the number of mature application module, we can make this system more intelligent and easy to use. Such as acceleration monitoring module can automatically monitor patient sleep state and automatic monitoring of patient motion; the Bluetooth module can automatically upload the data connection to the host, and so on. Furthermore this article also verified the system's accuracy and repeatability by actual measurement, and by comparing to the Finapres noninvasive blood pressure monitor, the blood pressure measurement deviation is measured less than 5mm Hg, which indicates that the developed system conform to the design requirements.