The Study Of Continuous Blood Pressure Measurement With Infrared Pulse Sensor

A variety of cardiovascular diseases, especially hypertension- "The First Killer", has become the biggest threat to human health. Effective measurement of blood pressure is of great significance for the prevention and treatment of high blood pressure. Human blood pressure is a dynamic value. Usually, doctors can only provide a single measurement, which does not accurately reflect the true blood pressure levels and cardiovascular status of the patients. Continuous blood pressure measurement can monitor the changes of blood pressure in real time, can help to assess the effect of antihypertensive drugs on the treatment of patients. In this paper, we mainly study a method of continuous blood pressure measurement based on pulse wave feature points.The main content of this paper can be divided into three parts:(1) The infrared pulse sensor HKG-07 B will be used to obtain the pulse wave signal from the human fingertips. Considering the reason that there are some shortcomings in the measurement accuracy and noise immunity. So this paper proposes several methods to improve measurement accuracy and anti noise of the sensor.(2) In this paper, a hybrid algorithm is used to identify the feature points. It combines two different methods to complete the recognition. Firstly, it use the wavelet transform to divide the period, find out the reference point C, and then use it as the division point of the pulse wave. And then use quadratic differential method to identify the left feature points. Simulative experimental results, under the MATLAB software,compared with the traditional methods, show that the recognition accuracy of this method is significantly improved.(3)Finally is the correlation analysis between the feature points and the blood pressure.Set up the correlation equation between the blood pressure and the feature points, using the SPASS tool. Then the blood pressure can be estimated through the feature points of the pulse wave.Experimental result show that, the improvement measures of HKG-07 B through several methods can effectively improve the measurement accuracy of the infrared pulse sensor. The combination of the quadratic differential method and wavelet transform can accurately identify the feature points of the measured pulse wave. And then we can establish the reliability correlation equation between feature points and blood pressure. The diastolic blood pressure and systolic pressure estimated by the characteristic points of the pulse wave are consistent with the blood pressure measured by the common electronic blood pressure gauge. Constantly collecting human pulse wave, then recognizing the feature points, combined with the relevant equations have been established, noninvasive continuous blood pressure measurement can be achieved.