The mainstream process of system management work, in which the development mode of measurement technology work is the default mode.

In the blood pressure measurement mode, complete the blood pressure measurement display and analyze the blood pressure data. If there are any abnormalities (high blood pressure, low blood pressure, slow heart rate, fast heart rate, error measurement, etc.), immediately give an alarm prompt. Alarm conditions:

Systolic blood pressure>145mmhg or systolic blood pressure<95mmhg

Diastolic blood pressure>90mmhg or<45mmhg;

Heart rate>105 or heart rate<45.

After the measurement is completed, prompt whether to save the data. The system can store up to 16 sets of data, with each set storing 331 records.

Under the operation management mode of viewing information records, 16 groups of blood pressure data can be called out by listing or generating line chart of daily, weekly and monthly blood pressure control, so as to facilitate further observation and analysis of the development of blood pressure changes in a certain period of time.

Blood pressure measurement process:

There are several important sets of sequences and data in the collection and processing of blood pressure measurements. Let the original static pressure signal sequence be {statk [i], i=0,1,..., n-1), and the pulse signal sequence be {use [i], i=0,1,..., n-1}. After normalization, the peak sequence {peak [i], i=0,1,...,..., N-1}, and the maximum value in the peak envelope is max_ peak。 The peak time interval sequence is {TIme_peak [i], i=0, 1,..., n-1).

In measurement mode, the air pump automatically pressurizes and inflates. When the pressure on the cuff exceeds or equals 200 millimeters of mercury and no pulse signal appears, the air in the cuff will stop and slowly release. After detecting the first peak, the pulse signal value is collected every 5 ms, and the pulse signal value and static pressure signal value are collected within a 5 ms cycle to obtain the static pressure signal sequence staTIC, respectively_ BP [i] and pulse signal sequence plus_ BP [i], determine whether the collected pulse signal value is a peak. If it is a peak, record the pulse signal value and static pressure signal value at this time, record the time difference from the previous peak to the current time, and generate sequence peaks respectively.

Peak value [i] and peak interval time [i]. In general, when the cuff pressure pc is ≤ 60mmhg, the peak pulse signal disappears. When the peak pulse signal cannot be detected for 4 consecutive seconds, the system exits the blood pressure measurement.

Workflow for calculating blood pressure and heart rate

Due to the lack of comprehensive theoretical derivation, the determination of feature points can only rely on the statistical induction of samples. Therefore, oscillographic blood pressure measurement is based on statistical methods and has a certain degree of discreteness. The data processing process includes filtering, calculation of heartbeat cycle, determination of average pressure position, and calculation of systolic and diastolic blood pressure.

Filter processing is mainly used to filter out the noise of peak [i] large jump data and improve the linearity of the original data. The heartbeat cycle refers to the time interval between the peaks of two pulse waves. In order to improve the accuracy of the results, the peak time interval sequence TIme during the deflation process is taken_ The arithmetic mean value of peak [i] is used to get the average cycle ta, then the heart rate is r=1/ta.

The average pressure and static pressure values correspond to the peak position of the pulse signal envelope. By comparing adjacent data, the maximum peak value of the pulse signal envelope can be obtained [a], and then the average pressure value pm=static value [a].

According to the principle of amplitude coefficient method, Ps/Pm=Ks and Pd/Pm=Kd. Due to the peak occurrence envelope analysis of pulse data signals, the position of patients' systolic and diastolic blood pressure in the static pressure change curve can be determined as follows: peak_ BP[b]／max_ Peak=Ks and peak_ BP[c]／max_ peak=Kd。 The corresponding values of b and c indicate that the positions of systolic and diastolic regulated blood pressure in the static pressure series are systolic pressure ps=static [b] and diastolic pressure pd=static [c]. Among them, the amplitude coefficients ks=0.48 and kd=0.58, which have wide applications in clinical medicine.

Experimental results and analysis

Three groups of measurers were selected, and this method of repetition and comparison was used to conduct a continuous measurement of the same measurer in the same development period by using the electronic sphygmomanometer and the mercury sphygmomanometer. The students of the measurement research results were compared and analyzed in enterprises to observe the consistency and accuracy of the measurement results, as listed in Table 1.

The experimental data show that the electronic sphygmomanometer can be used for clinical diagnosis and family health care. The error of blood pressure is less than 6 mmhg, and the error of heart rate is less than 3 times/min.