Based On Arm Blood Pressure Monitor

This project "Design of blood pressure monitor based on ARM" is carried out for the clinical medicine. Monitoring ambulatory blood pressure of human body and recording the changing rules to get a lot of information about autonomic nerve activity for clinical diagnosis.As a monitor for clinical use, development of instrument should be considered from the following aspects:Firstly, ensure stability and accuracy of the system. This point is the key and foundation of the instrument. Secondly, have good man-machine interface. Based on an accurate and stable system, clear interface and simple operation makes the users easier to accept our products. Finally, consider cost and overall design of instrument. Production cost is a problem that must be considered;on the basis of quality cost should be as low as possible, compact appearance is more popular with users.This paper compared the existing method of domestic and foreign non-invasive blood pressure’s measurement, summarized the advantages and disadvantages of various methods, and proposed a new method which combines Gauss fitting, oscillometric method and amplitude coefficient method to judge blood pressure’s value. Decision process of this method:extract the peak of sampled pulse wave, and then use Gauss curve to fit the peak point, find the maximum value of envelope and the cuff pressure is MAP, in the range of normalized value of DBP and SBP provided from amplitude coefficient method, find two feature points of the curve, the cuff pressure corresponding to the two feature points is DBP and SBP.Secondly, use microprocessor LPC2132as core, design peripheral circuit, including power supply circuit, pump and valve drive circuit, signal processing circuit and serial communication circuit, write slave computer programs to design a blood pressure module that can be widely used. Connect the module with PC, so that the software of PC can control the blood pressure module and show monitoring data real-time, stably and accurately. PC interface displays monitoring data, historical records and trend chart, alarm log and so on. PC connects the voice module through the parallel port, when the monitor parameter is higher than the limit value, the system will give corresponding alarm voice. PC software using Visual Basic language, clear interface enables the users easy to operate and see the monitoring data intuitively.After the theory research and feasibility analysis, according to different groups of people, test the system in aspects of accuracy and repeatability. Experiments show that this system can monitor blood pressure of patients accurately, stably and real-time.