Blood pressure calculation method and electronic sphygmomanometer

Abstract

The invention relates to the field of medical instruments, in particular to a blood pressure calculation method and an electronic sphygmomanometer. The blood pressure calculation method comprises the steps that a pressure value sequence in an air bag is continuously collected, and an air pressure pulsation sequence and a basic air pressure sequence are extracted based on the pressure value sequence; generating an envelope line according to the air pressure pulsation sequence, and determining an envelope line peak value based on the envelope line; determining diastolic pressure and systolic pressure according to the envelope peak value; and determining a rising and falling time ratio according to the air pressure pulsation sequence, and correcting diastolic pressure and systolic pressure according to the rising and falling time ratio. A blood pressure calculation method and an electronic sphygmomanometer are applied to the electronic sphygmomanometer, and the blood pressure measurement precision of the electronic sphygmomanometer can be improved.

Description

Technical Field

[0001] The present invention relates to the field of medical devices, and more particularly, to a blood pressure calculation method and an electronic sphygmomanometer. Background Art

[0002] An electronic sphygmomanometer based on the oscillometric principle calculates the systolic / diastolic blood pressure of the subject by winding an air bag around a part of the human body and adjusting the air pressure in the air bag, and then collecting the data of the air pressure in the air bag. However, this method has the problem of low accuracy of blood pressure calculation results. Summary of the Invention

[0003] The object of the present invention is to provide a blood pressure calculation method and an electronic sphygmomanometer, which are applied to an electronic sphygmomanometer to improve the blood pressure measurement accuracy of the electronic sphygmomanometer.

[0004] The embodiments of the present invention can be implemented as follows:

[0005] The present invention provides a blood pressure calculation method, including:

[0006] Continuously collect the pressure value sequence in the air bag, and extract the air pressure pulsation sequence and the basic air pressure sequence based on the pressure value sequence;

[0007] Generate an envelope based on the air pressure pulsation sequence, and determine the envelope peak based on the envelope;

[0008] Determine the diastolic blood pressure and the systolic blood pressure according to the envelope peak;

[0009] Determine the rise and fall time ratio according to the air pressure pulsation sequence, and correct the diastolic blood pressure and the systolic blood pressure according to the rise and fall time ratio.

[0010] In an alternative embodiment, the step of determining the rise and fall time ratio according to the air pressure pulsation sequence includes:

[0011] Determine the wave peak of the air pressure pulsation amplitude in the air pressure pulsation sequence per unit time, and the two wave valleys before and after the wave peak;

[0012] The time from the wave valley before the wave peak to the wave peak is the rise time; the time from the wave valley after the wave peak to the wave peak is the fall time;

[0013] The ratio of the rise time to the fall time is the rise and fall time ratio.

[0014] In an alternative embodiment, the step of correcting the diastolic blood pressure according to the rise and fall time ratio includes:

[0015] Correct the diastolic blood pressure according to the formula: Di a = A + B * Di a0 + C * Rtef;

[0016] Wherein, Di a is the corrected diastolic blood pressure; A, B, and C are coefficients; Di a0 is the diastolic blood pressure; and Rtef is the rise-fall time ratio.

[0017] In an alternative embodiment, before the step of correcting the diastolic blood pressure and the systolic blood pressure based on the rise-fall time ratio, the blood pressure calculation method further includes:

[0018] Collect N pieces of test data, arrange the diastolic blood pressure reference values in the collected test data in sequence as a column vector, denoted as Y; create a column vector of length N with all elements being 1, denoted as x1;

[0019] Calculate the diastolic blood pressure data in the collected test data, arrange them in sequence as a column vector, denoted as x2;

[0020] Calculate the rise-fall time ratio in the collected test data, arrange them in sequence as a column vector, denoted as x3;

[0021] Arrange the aforementioned column vectors x1 to x3 from left to right to form a 255-row and 3-column matrix, i.e., [x1, x2, x3], denoted as X;

[0022] Perform fitting on P in the equation Y = X * P; P is a column vector of length 3, and its elements respectively correspond to the coefficients A, B, and C in sequence.

[0023] In an alternative embodiment, the value range of coefficient A is [-5, 25], the value range of coefficient B is [0, 2], and the value range of coefficient C is [-3, 5].

[0024] In an alternative embodiment, the step of correcting the systolic blood pressure based on the rise-fall time ratio includes:

[0025] Correct the systolic blood pressure according to the formula: Sys = D + E * Sys0 + F * Rtef;

[0026] Wherein, Sys is the corrected systolic blood pressure; D, E, and F are all coefficients; Sys0 is the systolic blood pressure; and Rtef is the rise-fall time ratio.

[0027] In an alternative embodiment, before the step of correcting the diastolic blood pressure and the systolic blood pressure based on the rise-fall time ratio, the blood pressure calculation method further includes:

[0028] Collect N pieces of test data, arrange the systolic blood pressure reference values in the collected test data in sequence as a column vector, denoted as Y; create a column vector of length N with all elements being 1, denoted as x1;

[0029] Calculate the systolic blood pressure data in the collected test data, arrange them in sequence as a column vector, denoted as x2;

[0030] Calculate the rise and fall time ratio in the collected test data, arrange them in sequence as a column vector, denoted as x3;

[0031] Arrange the aforementioned column vectors x1 to x3 from left to right to form an N-row and 3-column matrix, that is, [x1, x2, x3], denoted as X;

[0032] Perform fitting on P in the equation Y = X * P; P is a column vector with a length of 3, and its elements respectively correspond to the coefficients D, E, and F in sequence.

[0033] In an alternative embodiment, the value range of the coefficient D is [-5, 25], the value range of the coefficient E is [0, 2], and the value range of the coefficient F is [-3, 5].

[0034] In an alternative embodiment, the steps of determining the diastolic blood pressure and systolic blood pressure according to the envelope peak include:

[0035] Determine the maximum amplitude value according to the envelope, and multiply the maximum amplitude value by the diastolic blood pressure coefficient to obtain the air pressure pulsation amplitude corresponding to the diastolic blood pressure; find the point equal to its value on the left side of the maximum amplitude value in the envelope, and the base air pressure corresponding to this point is the diastolic blood pressure;

[0036] Determine the maximum amplitude value according to the envelope, and multiply the maximum amplitude value by the systolic blood pressure coefficient to obtain the air pressure pulsation amplitude corresponding to the systolic blood pressure; find the point equal to its value on the right side of the maximum amplitude value in the envelope, and the base air pressure corresponding to this point is the diastolic blood pressure;

[0037] Among them, the value range of the diastolic blood pressure coefficient is [0.2, 0.7], and the value range of the systolic blood pressure coefficient is [0.4, 0.9].

[0038] In a second aspect, the present invention provides an electronic sphygmomanometer, which includes a main body and a control unit connected to the main body. The control unit is used to execute the above-mentioned blood pressure calculation method.

[0039] The beneficial effects of the blood pressure calculation method and the electronic sphygmomanometer provided by the embodiments of the present invention include:

[0040] The blood pressure calculation method includes: continuously collecting the pressure value sequence in the air bag, and extracting the air pressure pulsation sequence and the base air pressure sequence based on the pressure value sequence; generating an envelope according to the air pressure pulsation sequence, and determining the envelope peak based on the envelope; determining the diastolic blood pressure and systolic blood pressure according to the envelope peak; determining the rise and fall time ratio according to the air pressure pulsation sequence, and correcting the diastolic blood pressure and systolic blood pressure based on the rise and fall time ratio. The blood pressure calculation method and the electronic sphygmomanometer are applied to the electronic sphygmomanometer and can improve the blood pressure measurement accuracy of the electronic sphygmomanometer. Brief Description of the Drawings

[0041] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0042] Figure 1 It is a diagram of the air pressure value inside the measurement air bag of the blood pressure calculation method in the prior art;

[0043] Figure 2 It is the extracted air pressure pulsation of the blood pressure calculation method in the prior art;

[0044] Figure 3 It is a diagram of the envelope line and the smoothed envelope line of the blood pressure calculation method in the prior art;

[0045] Figure 4 It is a diagram of the systolic blood pressure and diastolic blood pressure calculation of the blood pressure calculation method in the prior art;

[0046] Figure 5 It is a diagram of the rise and fall time ratio in the blood pressure calculation method provided in this embodiment;

[0047] Figure 6 It is a step diagram of the blood pressure calculation method provided in this embodiment. Detailed implementation manners

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0049] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0050] It should be noted that: similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0051] In the description of the present invention, it should be noted that if terms such as "upper", "lower", "inner", "outer", etc. are used to indicate the orientation or positional relationship, it is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use. This is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0052] In addition, if terms such as "first", "second", etc. are only used for distinguishing descriptions, they should not be construed as indicating or implying relative importance.

[0053] It should be noted that, without conflict, the features in the embodiments of the present invention can be combined with each other.

[0054] The inventor has found through research that an electronic sphygmomanometer using the oscillometric principle collects the data of the air pressure in the air bag by winding the air bag around a certain part of the human body and adjusting the air pressure in the air bag, and calculates the systolic / diastolic blood pressure of the subject based on this.

[0055] Specifically, by controlling components such as an air pump and an air valve, the air bag can be inflated / deflated, causing a change in the air volume in the air bag, further resulting in a change in the air pressure in the air bag. The air pressure change caused by inflation and deflation is called the basic air pressure change; when the blood vessels in the part of the human body wound by the air bag are compressed by the air bag, the pulsation of the blood vessels will also cause a change in the air pressure in the air bag. The air pressure change caused by the pulsation of the blood vessels is called air pressure pulsation. Moreover, when the basic air pressure changes, the degree of compression of the blood vessels by the air bag also changes, and the amplitude of the air pressure pulsation also changes. After collecting the air pressure pulsation sequence, the blood pressure of the subject is calculated based on its envelope characteristics.

[0056] For the inflation / deflation of the air bag, there are two schemes. One is to inflate quickly and then deflate gently, and the air pressure pulsation information is collected during the gentle deflation process; the other is to inflate gently and deflate quickly, and the air pressure pulsation information is collected during the gentle inflation process. Whether it is an inflation-type or deflation-type measurement, the abscissa of its envelope (taking the abscissa as the basic air pressure) is in the order from large to small from left to right, and the envelopes generated by the two measurement methods are the same.

[0057] Taking the inflation-type measurement as an example, the blood pressure calculation steps are as follows:

[0058] First step, continuously collect the air pressure values in the air bag during the inflation process. As Figure 1 shown, in Figure 1 , the abscissa is the sampling point, 64 points correspond to 1 second, the ordinate is the air pressure, and the unit is mmHg;

[0059] Step 2: Extract all the air pressure pulsations contained in the air pressure values measured in the previous step, for example, by high-pass filtering, as Figure 2 shown. In Figure 2 , the abscissa is the sampling point, 64 points corresponding to 1 second, and the ordinate is the air pressure, with the unit of mmHg;

[0060] Step 3: Use the amplitudes of all the previous air pressure pulsations as the ordinate and their corresponding base air pressures as the abscissa to generate an envelope line, and perform smoothing processing on the envelope line (optional), as Figure 3 shown. In Figure 3 , the abscissa is the base air pressure corresponding to the air pressure pulsation, with the unit of mmHg, and the ordinate is the amplitude of the air pressure pulsation, with the unit of mmHg. The solid line is the original envelope line, and the dashed line is the smoothed envelope line;

[0061] Step 4: Identify the maximum value (maximum amplitude) of the envelope line, which is regarded as the maximum amplitude of the air pressure pulsation;

[0062] Step 5: Multiply the maximum value of the previous envelope line by the diastolic blood pressure coefficient to obtain the amplitude of the air pressure pulsation corresponding to the diastolic blood pressure; find the point on the left side of the envelope line that is equal to this value, and the base air pressure corresponding to this point is the diastolic blood pressure;

[0063] Step 6: Multiply the maximum value of the previous envelope line by the systolic blood pressure coefficient to obtain the amplitude of the air pressure pulsation corresponding to the systolic blood pressure; find the point on the right side of the envelope line that is equal to this value, and the base air pressure corresponding to this point is the systolic blood pressure.

[0064] Step 4: Identify the maximum value (maximum amplitude) of the envelope line, which is regarded as the maximum amplitude of the air pressure pulsation;

[0065] Step 5: Multiply the maximum value of the previous envelope line by the diastolic blood pressure coefficient to obtain the amplitude of the air pressure pulsation corresponding to the diastolic blood pressure; find the point on the left side of the envelope line that is equal to this value, and the base air pressure corresponding to this point is the diastolic blood pressure;

[0066] Step 6: Multiply the maximum value of the previous envelope line by the systolic blood pressure coefficient to obtain the amplitude of the air pressure pulsation corresponding to the systolic blood pressure; find the point on the right side of the envelope line that is equal to this value, and the base air pressure corresponding to this point is the systolic blood pressure.

[0067] Steps 4 to 6 are as Figure 4 shown. In Figure 4 , the abscissa is the base air pressure corresponding to the air pressure pulsation, with the unit of mmHg, and the ordinate is the amplitude of the air pressure pulsation, with the unit of mmHg. The black curve is the smoothed envelope line. The aforementioned wound part of the human body can be the upper arm or the wrist; correspondingly, the air bag can also be a cuff or a wristband.

[0068] Based on the above method, through further research by the inventors, it is found that when calculating diastolic blood pressure / systolic blood pressure, only the envelope line of the air pressure pulsation amplitude is used. However, according to clinical data analysis, diastolic blood pressure / systolic blood pressure is also related to the "time ratio of the rising edge to the falling edge of the maximum air pressure pulsation" (hereinafter referred to as "rise-fall time ratio"); that is, the existing technology has the problem of insufficient accuracy of blood pressure calculation results due to the use of less information. Based on this, the inventors proposed a method for calculating diastolic blood pressure / systolic blood pressure that takes into account the characteristics of air pressure pulsation waveform data, thereby improving the accuracy of the sphygmomanometer. Specifically, this embodiment provides a blood pressure calculation method, including:

[0069] Continuously collect the pressure value sequence in the air bag, and extract the air pressure pulsation sequence and the basic air pressure sequence based on the pressure value sequence;

[0070] Generate an envelope line according to the air pressure pulsation sequence, and determine the envelope line peak based on the envelope line;

[0071] Determine the diastolic blood pressure and systolic blood pressure according to the envelope line peak;

[0072] Determine the rise-fall time ratio according to the air pressure pulsation sequence, and correct the diastolic blood pressure and systolic blood pressure according to the rise-fall time ratio.

[0073] In summary, this blood pressure calculation method and electronic sphygmomanometer are applied to an electronic sphygmomanometer. It first calculates the diastolic blood pressure / systolic blood pressure, and then according to the rise-fall time ratio, substitutes it into the accurate calculation formula of diastolic blood pressure / systolic blood pressure to obtain the final blood pressure calculation result. Such a calculation method can improve the blood pressure measurement accuracy of the electronic sphygmomanometer.

[0074] Further, please refer to Figure 5 , in this embodiment, the step of determining the rise-fall time ratio according to the air pressure pulsation sequence includes:

[0075] Determine the wave peak of the air pressure pulsation amplitude in the air pressure pulsation sequence within a unit time, and the two wave troughs before and after the wave peak;

[0076] The time from the wave trough before the wave peak to the wave peak is the rise time; the time from the wave trough after the wave peak to the wave peak is the fall time;

[0077] The ratio of the rise time to the fall time is the rise-fall time ratio.

[0078] Specifically, Figure 5 the abscissa in is the sampling point, 64 points is 1 second, the ordinate is the change amount of the air pressure pulsation amplitude within a unit time, the unit is mmHg / s, and the waveform is the one with the largest amplitude among all effective pulse waves. Based on Figure 5 find the wave peak of this pulse wave and the two wave troughs before and after it;

[0079] The time from the trough (front) to the peak is the rise time, and the time from the peak to the trough (rear) is the fall time; taking the rise time as the numerator and the fall time as the denominator, the ratio is the rise-fall time ratio.

[0080] Furthermore, in this embodiment, the steps of correcting the diastolic blood pressure according to the rise-fall time ratio include:

[0081] Correct the diastolic blood pressure according to the formula: Dia = A + B * Dia0 + C * Rtef;

[0082] where Dia is the corrected diastolic blood pressure; A, B, and C are coefficients; Dia0 is the diastolic blood pressure; and Rtef is the rise-fall time ratio.

[0083] Moreover, the value range of coefficient A is [-5, 25], the value range of coefficient B is [0, 2], and the value range of coefficient C is [-3, 5]. In addition, the units of A and C are mmHg, and B and Rtef are dimensionless.

[0084] In addition, before the steps of correcting the diastolic blood pressure and systolic blood pressure according to the rise-fall time ratio, calibration of coefficients A, B, and C is also required. Based on this, the blood pressure calculation method further includes:

[0085] Collect N pieces of test data, arrange the diastolic blood pressure reference values in the collected test data in sequence as a column vector, denoted as Y; create a column vector with a length of N and all elements being 1, denoted as x1;

[0086] Calculate the diastolic blood pressure data in the collected test data, arrange them in sequence as a column vector, denoted as x2;

[0087] Calculate the rise-fall time ratio in the collected test data, arrange them in sequence as a column vector, denoted as x3;

[0088] Arrange the aforementioned column vectors x1 to x3 from left to right to form a 255-row and 3-column matrix, i.e., [x1, x2, x3], denoted as X;

[0089] Perform fitting on P in the equation Y = X * P; P is a column vector with a length of 3, and its elements respectively correspond to coefficients A, B, and C in sequence.

[0090] Specifically, the coefficients in the above formula are all from the analysis and statistics of effective clinical test data. The larger the amount of clinical data, the better, and there are requirements for the distribution of the test population. The wider the distribution of the subject type / blood pressure level, the better. The number of cases, distribution range, and test method of the clinical data refer to the requirements of ISO81060:2013. The quantity and distribution of the clinical data used for calibrating the coefficients in this method are shown in Table 1:

[0091]

[0092] Table 1 Quantity and Distribution of Clinical Data Used for Calibrating Formula Coefficients

[0093] Taking 255 clinical data collected from 85 subjects in Table 1 as an example for illustration;

[0094] The data sources for calibrating coefficients A, B, and C are 255 clinical data from 85 subjects in Table 1, that is, N = 255;

[0095] According to the 255 collected subject data, the diastolic reference values in the collected subject data are arranged in sequence as a column vector, denoted as Y;

[0096] Create a column vector of length 255 with all elements being 1, denoted as x1;

[0097] Calculate the diastolic blood pressure data in the collected subject data and arrange them in sequence as a column vector, denoted as x2;

[0098] Calculate the rise and fall time ratio in the collected subject data and arrange them in sequence as a column vector, denoted as x3;

[0099] Arrange the aforementioned column vectors x1 to x3 from left to right to form a 255-row and 3-column matrix, that is, [x1, x2, x3], denoted as X;

[0100] Perform fitting on P in the equation Y = X * P; P is a column vector of length 3, and its elements respectively correspond to coefficients A, B, and C in sequence.

[0101] It should be noted that during the fitting process, the regress function in software matlab can be used; the above fitting method can also use other methods, such as using the polyfit function and cftool toolbox in software matlab, as well as the trend prediction / regression analysis function of other software such as EXCEL.

[0102] Based on the above steps of correcting diastolic blood pressure according to the rise and fall time ratio, the principle of correcting systolic blood pressure according to the rise and fall time ratio is roughly the same as that of correcting diastolic blood pressure. Specifically, the steps of correcting systolic blood pressure according to the rise and fall time ratio include:

[0103] Correct systolic blood pressure according to the formula: Sys = D + E * Sys0 + F * Rtef;

[0104] Among them, Sys is the corrected systolic blood pressure; D, E, and F are all coefficients; Sys0 is the systolic blood pressure; Rtef is the rise and fall time ratio.

[0105] Among them, the value range of coefficient D is [-5, 25], the value range of coefficient E is [0, 2], and the value range of coefficient F is [-3, 5]. Additionally, the units of D and F are mmHg, and E is dimensionless.

[0106] Moreover, before the step of correcting the diastolic blood pressure and systolic blood pressure based on the rise and fall time ratio, the calibration of coefficients D, E, and F is also required. Based on this, the blood pressure calculation method further includes:

[0107] Collect N pieces of test data. Arrange the systolic blood pressure reference values in the collected test data in sequence as a column vector, denoted as Y; create a column vector with a length of N and all elements being 1, denoted as x1;

[0108] Calculate the systolic blood pressure data in the collected test data and arrange them in sequence as a column vector, denoted as x2;

[0109] Calculate the rise and fall time ratio in the collected test data and arrange them in sequence as a column vector, denoted as x3;

[0110] Arrange the aforementioned column vectors x1 to x3 from left to right to form a matrix with N rows and 3 columns, that is, [x1, x2, x3], denoted as X;

[0111] Perform fitting on P in the equation Y = X * P; P is a column vector with a length of 3, and its elements respectively correspond to coefficients D, E, and F in sequence.

[0112] The following takes 85 subjects in Table 1 above and collecting 255 pieces of clinical data as an example for illustration;

[0113] The data sources for calibrating coefficients D, E, and F are 255 pieces of clinical data of 85 subjects in Table 1, that is, N = 255;

[0114] Collect 255 pieces of test data. Arrange the systolic blood pressure reference values in the collected test data in sequence as a column vector, denoted as Y; create a column vector with a length of 255 and all elements being 1, denoted as x1;

[0115] Calculate the systolic blood pressure data in the collected test data and arrange them in sequence as a column vector, denoted as x2;

[0116] Calculate the rise and fall time ratio in the collected test data and arrange them in sequence as a column vector, denoted as x3;

[0117] Arrange the aforementioned column vectors x1 to x3 from left to right to form a matrix with 255 rows and 3 columns, that is, [x1, x2, x3], denoted as X;

[0118] Fit P in the equation Y = X * P; P is a column vector of length 3, and its elements correspond to coefficients D, E, and F respectively in sequence.

[0119] Further, in this embodiment, the steps of determining diastolic blood pressure and systolic blood pressure according to the envelope peak include:

[0120] Determine the maximum amplitude value according to the envelope, and multiply the maximum amplitude value by the diastolic blood pressure coefficient to obtain the blood pressure pulsation amplitude corresponding to the diastolic blood pressure; find the point equal to its value on the left side of the maximum amplitude value in the envelope, and the base blood pressure corresponding to this point is the diastolic blood pressure;

[0121] Determine the maximum amplitude value according to the envelope, and multiply the maximum amplitude value by the systolic blood pressure coefficient to obtain the blood pressure pulsation amplitude corresponding to the systolic blood pressure; find the point equal to its value on the right side of the maximum amplitude value in the envelope, and the base blood pressure corresponding to this point is the diastolic blood pressure;

[0122] Among them, the value range of the diastolic blood pressure coefficient is [0.2, 0.7], and the value range of the systolic blood pressure coefficient is [0.4, 0.9].

[0123] Based on the above, the present invention provides an electronic sphygmomanometer, which includes a main body and a control unit connected to the main body. The control unit is used to execute the above blood pressure calculation method. By adopting the above blood pressure calculation method, the blood pressure measurement accuracy of the electronic sphygmomanometer can be improved.

[0124] In summary, please refer to Figure 6 , and the steps of the blood pressure calculation method are as follows:

[0125] Step ST1, during the inflation process, continuously collect the air pressure value sequence in the air bag. In the collected air pressure value sequence, on top of the continuously stable base air pressure, there is a superposition of air pressure pulsations with continuously changing oscillation amplitudes;

[0126] Step ST2, extract the air pressure pulsation sequence from the air pressure value sequence collected in step ST1; specifically, filter the air pressure value sequence, such as high-pass filtering, band-pass filtering, or moving average filtering, etc.;

[0127] Step ST3, generate an envelope according to the air pressure pulsation sequence obtained in step ST2; specifically, identify the amplitude of each air pressure pulsation in the air pressure pulsation sequence, and use the amplitudes of all air pressure pulsations as the ordinate and their respective corresponding base air pressures as the abscissa to generate an envelope. Then, smooth the envelope, and the methods include multi-point weighted average, Fourier transform and inverse transform, etc.;

[0128] Step ST4, identify the envelope peak; specifically, obtain the maximum value of the envelope obtained in step ST3;

[0129] Step ST5, roughly calculate the systolic blood pressure / diastolic blood pressure; specifically, multiply the maximum value of the aforementioned envelope line by the diastolic blood pressure coefficient to obtain the amplitude of the air pressure pulsation corresponding to the diastolic blood pressure; find the point on the left side of the envelope line that is equal to its value, and the corresponding basic air pressure at this point is the diastolic blood pressure; multiply the maximum value of the aforementioned envelope line by the systolic blood pressure coefficient to obtain the amplitude of the air pressure pulsation corresponding to the systolic blood pressure; find the point on the right side of the envelope line that is equal to its value, and the corresponding basic air pressure at this point is the systolic blood pressure; both the diastolic blood pressure coefficient and the systolic blood pressure coefficient are obtained based on clinical data analysis, the value range of the diastolic blood pressure coefficient is between [0.2, 0.7], and the value range of the systolic blood pressure coefficient is between [0.4, 0.9];

[0130] Step ST6, calculate the rise and fall time ratio. Specifically, based on Step ST2, find the air pressure pulsation with the largest amplitude and its peak, and then find the two troughs before and after the peak. The time from the previous trough to the peak is recorded as the "rise time", and the time from the peak to the subsequent trough is recorded as the "fall time". Divide the rise time by the fall time to obtain the rise and fall time ratio;

[0131] Step ST7, accurately calculate the systolic blood pressure / diastolic blood pressure. Specifically, after obtaining the rise and fall time ratio of Step ST6 and the systolic blood pressure / diastolic blood pressure roughly calculated in Step ST5, substitute them into the "step of correcting the systolic blood pressure according to the rise and fall time ratio" and the "step of correcting the diastolic blood pressure according to the rise and fall time ratio" respectively. The results obtained are the accurately calculated systolic blood pressure / diastolic blood pressure.

[0132] Compared with the existing well-known technologies, the accuracy of the diastolic blood pressure / systolic blood pressure calculated by the blood pressure calculation scheme provided in this embodiment is higher. Specifically, randomly select 10 adult subjects for comparative measurement. Each subject is tested three times in turn using an electronic blood pressure monitor (well-known technology), an electronic blood pressure monitor (blood pressure calculation method provided in this embodiment), and a mercury blood pressure monitor, and the average values are calculated and recorded respectively. As shown in Table 2, the comparison results of the test accuracy are shown in Table 3.

[0133]

[0134] Table 2 List of blood pressure test data of this method and well-known technologies

[0135]

[0136] Table 3 Comparison of blood pressure accuracy between this method and well-known technologies

[0137] It can be seen from the statistical results that after adopting the blood pressure calculation method provided in this embodiment, the average difference and standard deviation of the systolic blood pressure / diastolic blood pressure have decreased to varying degrees, and the blood pressure calculation accuracy has been significantly improved.

[0138] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A blood pressure calculation method, characterized in that, Including: Continuously collect the pressure value sequence in the air bag, and extract the air pressure pulsation sequence and the basic air pressure sequence based on the pressure value sequence; Generate an envelope based on the air pressure pulsation sequence, and determine the envelope peak value based on the envelope; Determine the diastolic blood pressure and systolic blood pressure according to the envelope peak value; Determine the rise and fall time ratio according to the air pressure pulsation sequence, and correct the diastolic blood pressure and the systolic blood pressure according to the rise and fall time ratio.

2. The blood pressure calculation method according to claim 1, wherein: The step of determining the rise and fall time ratio according to the air pressure pulsation sequence includes: Determine the wave peaks of the air pressure pulsation amplitude in the air pressure pulsation sequence per unit time, and the two wave valleys before and after the wave peak; The time from the wave valley before the wave peak to the wave peak is the rise time; the time from the wave valley after the wave peak to the wave peak is the fall time; The ratio of the rise time to the fall time is the rise and fall time ratio.

3. The blood pressure calculation method according to claim 2, wherein: The step of correcting the diastolic blood pressure according to the rise and fall time ratio includes: Correct the diastolic blood pressure according to the formula: Dia = A + B * Dia0 + C * Rtef; Wherein, Dia is the corrected diastolic blood pressure; A, B, and C are coefficients; Dia0 is the diastolic blood pressure; Rtef is the rise and fall time ratio.

4. The blood pressure calculation method according to claim 3, wherein: Before the step of correcting the diastolic blood pressure and the systolic blood pressure according to the rise and fall time ratio, the blood pressure calculation method further includes: Collect N pieces of test data, arrange the diastolic blood pressure reference values in the collected test data in sequence as a column vector, denoted as Y; create a column vector with a length of N and all elements being 1, denoted as x1; Calculate the diastolic blood pressure data in the collected test data, arrange them in sequence as a column vector, denoted as x2; Calculate the rise and fall time ratios in the collected test data, arrange them in sequence as a column vector, denoted as x3; Arrange the foregoing column vectors x1 to x3 from left to right to form a 255-row and 3-column matrix, that is, [x1, x2, x3], denoted as X; Perform fitting on P in the equation Y = X * P; P is a column vector with a length of 3, and its elements respectively correspond to the coefficients A, B, and C in sequence.

5. The blood pressure calculation method according to claim 4, wherein: The value range of coefficient A is [-5, 25], the value range of coefficient B is [0, 2], and the value range of coefficient C is [-3, 5].

6. The blood pressure calculation method according to claim 2, wherein: The step of correcting the systolic blood pressure according to the rise and fall time ratio includes: Correct the systolic blood pressure according to the formula: Sys = D + E * Sys0 + F * Rtef; Wherein, Sys is the corrected systolic blood pressure; D, E, and F are all coefficients; Sys0 is the systolic blood pressure; Rtef is the rise and fall time ratio.

7. The blood pressure calculation method according to claim 6, wherein: Before the step of correcting the diastolic blood pressure and the systolic blood pressure according to the lift time ratio, the blood pressure calculation method further includes: Collect N pieces of test data, arrange the systolic blood pressure reference values in the collected test data in sequence as a column vector, denoted as Y; create a column vector with a length of N and all elements being 1, denoted as x1; Calculate the systolic blood pressure data in the collected test data and arrange them in sequence as a column vector, denoted as x2; Calculate the lift time ratio in the collected test data and arrange them in sequence as a column vector, denoted as x3; Arrange the aforementioned column vectors x1 to x3 from left to right to form an N-row and 3-column matrix, that is, [x1, x2, x3], denoted as X; Fit P in the equation Y = X * P; P is a column vector with a length of 3, and its elements respectively correspond to the coefficients D, E, and F in sequence.

8. The blood pressure calculation method according to claim 7, wherein: The value range of the coefficient D is [-5, 25], the value range of the coefficient E is [0, 2], and the value range of the coefficient F is [-3, 5].

9. The blood pressure calculation method according to any one of claims 1-8, wherein: The step of determining the diastolic blood pressure and the systolic blood pressure according to the envelope peak value includes: Determine the maximum amplitude value according to the envelope line, and multiply the maximum amplitude value by the diastolic blood pressure coefficient to obtain the air pressure pulsation amplitude corresponding to the diastolic blood pressure; find a point equal to its value on the left side of the maximum amplitude value in the envelope line, and the base air pressure corresponding to this point is the diastolic blood pressure; Determine the maximum amplitude value according to the envelope line, and multiply the maximum amplitude value by the systolic blood pressure coefficient to obtain the air pressure pulsation amplitude corresponding to the systolic blood pressure; find a point equal to its value on the right side of the maximum amplitude value in the envelope line, and the base air pressure corresponding to this point is the diastolic blood pressure; Among them, the value range of the diastolic blood pressure coefficient is [0.2, 0.7], and the value range of the systolic blood pressure coefficient is [0.4, 0.9].

10. An electronic sphygmomanometer, wherein: The electronic sphygmomanometer includes a main body and a control unit connected to the main body, and the control unit is used to execute the blood pressure calculation method according to any one of claims 1-9.

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