CN113679364A

CN113679364A - Blood pressure measurement and calculation method

Info

Publication number: CN113679364A
Application number: CN202110907867.5A
Authority: CN
Inventors: 王怡; 盛奕冰
Original assignee: Yanhe Intelligent Technology Hangzhou Co ltd
Current assignee: Yanhe Intelligent Technology Hangzhou Co ltd
Priority date: 2021-08-09
Filing date: 2021-08-09
Publication date: 2021-11-23

Abstract

The invention discloses a blood pressure measurement and calculation method, which is applied to a blood pressure measurement device, wherein the blood pressure measurement device comprises an air bag assembly and an air pump, and the calculation method comprises the following steps: the blood pressure measuring device controls the air pump to inflate the air bag assembly and continuously detects a pressure signal in the air bag assembly in the inflating process; the blood pressure measuring device obtains a pulse wave signal and a static pressure signal through the pressure signal; the blood pressure measuring device determines at least one characteristic value through the pressure signal; the blood pressure measuring device determines an original blood pressure value through the pulse wave signal; the blood pressure measuring device determines a final blood pressure value of the measurement part according to the characteristic value and the original blood pressure value. The invention can reduce the error of blood pressure measurement caused by the fitting degree of wearing, the artery depth degree and the compression capability of the air bag assembly, and improve the accuracy of blood pressure measurement.

Description

Blood pressure measurement and calculation method

Technical Field

The invention relates to the technical field of blood pressure measurement, in particular to a blood pressure measurement and calculation method.

Background

Blood pressure is an important physiological parameter of human body, and has very important value in clinical diagnosis. With the continuous development of electronic technology, the electronic sphygmomanometer becomes the most widely used sphygmomanometer in the market at present. Electronic blood pressure meters on the market are mainly based on arm type electronic blood pressure meters, which can realize more accurate blood pressure measurement, but are not portable in terms of volume or weight of the equipment, and are not convenient to use especially for users needing continuous real-time monitoring. Therefore, a wrist electronic sphygmomanometer is used as a household electronic sphygmomanometer, and is more convenient to use. With the intensive research on blood pressure detection, the wrist type sphygmomanometer gradually evolves into a blood pressure watch, a wrist strap sphygmomanometer and the like, and can realize real-time monitoring of blood pressure in a more portable manner.

The wrist electronic sphygmomanometer generally includes a wrist sphygmomanometer based on a PPG signal, a wrist sphygmomanometer based on a PPG and ECG signal, a wrist sphygmomanometer based on an oscillography, and the like. The wrist sphygmomanometer based on the PPG signal generally utilizes a photoelectric sensor to acquire a pulse wave waveform of a wrist part, and estimates a blood pressure value through a specific algorithm, wherein the accuracy of the blood pressure value is to be verified. The wrist sphygmomanometer based on the PPG and ECG signals acquires pulse waves of a wrist part through the photoelectric sensor, the PPG and the ECG signals are combined to analyze the time difference of the PPG and the ECG peaks, the cost is relatively high, and the acquisition is more complex. The accuracy of the oscillometric wrist sphygmomanometer is higher than that of the PPG signal wrist sphygmomanometer, and the acquisition method and cost of the oscillometric wrist sphygmomanometer are better than those of the oscillometric wrist sphygmomanometer based on the PPG and ECG methods.

According to the method, the pressure sensor is used for acquiring the pressure signal of the wrist which is the tested part, and under the ideal condition, the pressure of the gas in the air bag can be transmitted to the radial artery through the air bag and wrist tissues such as skin without loss, so that a relatively accurate pulse wave signal can be extracted from the pressure signal. However, in the actual measurement process, due to the influence of various factors such as the size of the wrist circumference, the wearing tightness, the artery depth, the air bag compression capacity and the like, the pressure in the air bag is deviated from the pressure actually pressed on the radial artery, and finally, the deviation of the blood pressure value obtained through measurement and calculation and the actual standard blood pressure value is overlarge. For example, if the patient wears the blood pressure measuring device loose, or the artery is deep, or the compression capacity of the air bag is weak, the pressure value in the air bag is higher than the pressure value actually compressed to the radial artery, and the measured blood pressure value is higher; if the wearing is too tight, the artery is shallow or the compression capacity of the air bag is too strong, the pressure value in the air bag is lower than the pressure value actually compressed in the radial artery, and the measured blood pressure value is lower.

Therefore, how to reduce the influence of the above difference is the key to improve the measurement accuracy for the wrist electronic blood pressure monitor.

Disclosure of Invention

The invention aims to provide a blood pressure measurement and calculation method which can reduce errors of blood pressure measurement caused by the fitting degree of wearing, the artery depth degree and the compression capability of an air bag assembly and improve the accuracy of blood pressure measurement.

In order to realize the purpose of the invention, the invention adopts the following technical scheme: a blood pressure measurement calculation method is applied to a blood pressure measurement device, the blood pressure measurement device comprises an air bag assembly and an air pump, and the calculation method comprises the following steps: the blood pressure measuring device controls the air pump to inflate the air bag assembly and continuously detects a pressure signal in the air bag assembly in the inflating process; the blood pressure measuring device obtains a pulse wave signal and a static pressure signal through the pressure signal; the blood pressure measuring device determines at least one characteristic value through the pressure signal; the blood pressure measuring device determines an original blood pressure value through the pulse wave signal; the blood pressure measuring device determines a final blood pressure value of the measurement part according to the characteristic value and the original blood pressure value.

By extracting the characteristic value in the pressure signal and correspondingly compensating the calculated original blood pressure value by using the corresponding characteristic value, the errors caused by the wearing fit degree, the artery depth degree and the compression capability of the air bag assembly are complemented, and the accuracy of blood pressure measurement is improved.

In one possible embodiment, the blood pressure measuring device determines at least one characteristic value from the pressure signal, including the blood pressure measuring device determining a characteristic value from the static pressure signal or the blood pressure measuring device determining a characteristic value from the pulse wave signal.

The characteristic value can be obtained through static pressure signals or pulse wave signals, and different characteristic values can be obtained through the separated static pressure signals and the separated pulse wave signals so as to obtain the characteristic values under different states.

In one possible design, the inflation process of the air pump to inflate the air bag component is controlled by the blood pressure measuring device and comprises a first inflation phase and a second inflation phase; the blood pressure monitoring device obtains a first characteristic point and a first characteristic value for judging the fitting degree of the blood pressure measuring device and the measuring part through a static pressure signal in a pressure signal of a first inflation stage; when the first characteristic value is larger than a first characteristic upper threshold value or the first characteristic value is smaller than a first characteristic lower threshold value, the blood pressure measuring device is excessively attached to the measuring part; when the first characteristic value is between the first characteristic lower threshold value and the first characteristic upper threshold value, the blood pressure measuring device is moderately attached to the measuring part.

When a user uses the blood pressure measuring device to measure the blood pressure, the wearing fit degree of the blood pressure measuring device is judged through the first characteristic value, and the blood pressure measurement deviation which is generated when the user wears the blood pressure measuring device under the standard or is still generated when an individual user wears the blood pressure measuring device under the standard is compensated.

The shape and thickness of the measuring part of different users, namely the wrist, are different, the device for fixing the blood pressure measuring device is generally a watchband, and the length of the watchband is controlled by the aid of jacks and watchbands which are uniformly spaced. The jack and the table of watchband are detained the check and are makeed according to most people's wrist type, consequently can make individual user can not select the best position under the prerequisite of standard wearing, appear slightly relaxing the watchband and can make the laminating more lax, and slightly tighten the watchband and can make the laminating condition too tight.

In the above solution, there is also a possible design that the blood pressure measuring device controls the air pump to inflate the air bag module in an inflation process including a first inflation phase and a second inflation phase; in the inflation process, a first inflation stage is performed before the static pressure signal reaches a preset pressure threshold, and the first characteristic point is a point when the static pressure signal reaches the preset pressure threshold; when the blood pressure measuring device is moderately attached to the measuring part, the blood pressure measuring device controls the inflation process to enter a second inflation stage; and when the blood pressure measuring device is excessively attached to the measuring part, the blood pressure measuring device finishes inflating and stops measuring.

When the first characteristic value is smaller than the first characteristic lower threshold value or the first characteristic value is larger than the first characteristic upper threshold value, the blood pressure measuring device is worn too loosely or too tightly at the measuring part. When the blood pressure measuring device is worn incorrectly, the next measurement operation is not suitable, the measurement is stopped, and the blood pressure measuring device gives a corresponding warning of wearing errors to the user. The problem of inaccurate blood pressure measurement caused by wearing errors of the user can be directly avoided.

In one possible design, the blood pressure measuring device determines a characteristic value through the pulse wave signal, wherein the characteristic value comprises a second characteristic point and a second characteristic value which are used for judging the position depth of the artery at the measuring part when a stable initial pulse wave signal appears in the pressure signal detected by the blood pressure measuring device; wherein the artery position of the measurement site is deeper or shallower when the second feature value is greater than a second upper feature threshold or the second feature value is less than a second lower feature threshold; the arterial location of the measurement site is moderate when the second feature value is between the second lower feature threshold and the second upper feature threshold.

The artery positions of different users have different depths, and if the artery positions are deeper, the pressure applied to the measurement part by the blood pressure measurement device is higher than the actual blood pressure value; if the position of the artery is shallow, the pressure applied to the measurement part by the blood pressure measuring device is lower than the actual blood pressure value, and the measured blood pressure value is deviated, so that the difference of the artery position of the measurement part of the user needs to be compensated through the second characteristic value so as to obtain an accurate final blood pressure value.

In the above technical solution, there is also a possible design, when a stable initial pulse wave signal appears in the pressure signal detected by the blood pressure measuring device, including when n pulse waves continuously appear in the pulse wave signal, the amplitudes of the n pulse waves are all greater than a preset amplitude, and the difference between the amplitudes is less than m, the stable initial pulse wave signal appears in the pressure signal.

In one possible design, the blood pressure measuring device determines a characteristic value through the pulse wave signal, and when the amplitude of the pulse wave signal reaches a first amplitude threshold value, the blood pressure measuring device acquires a third characteristic point and a third characteristic value for judging the compression capacity of the air bag component; when the third characteristic value is smaller than a third characteristic lower threshold value, the compression capacity of the air bag component is lower; when the third characteristic value is larger than a third characteristic upper threshold value, the compression capacity of the air bag component is higher; the compression capability of the airbag assembly is moderate when the third characteristic value is between the third lower characteristic threshold and the third upper characteristic threshold.

In the process of measuring the blood pressure by using the oscillometric method, if the compression capacity of the air bag component is low, the process of rising or falling the pulse wave amplitude becomes slow, namely the time for the pulse wave amplitude to reach the first amplitude threshold is long, the pressure to be applied is higher, and the corresponding pressure value is higher relatively; if the compression capacity of the airbag module is high, the rising or falling process of the pulse wave becomes rapid, i.e. the time for the pulse wave amplitude to reach the first amplitude threshold is short, and the pressure to be applied is low.

In the above technical solution, there is a possible design that the first amplitude threshold is determined by a maximum amplitude in the pulse wave signal detected by the blood pressure measuring device.

Obtaining a pulse amplitude change curve in the measurement process by adopting a pulse wave amplitude detection method, obtaining the maximum amplitude in the pulse wave signals from the pulse amplitude change curve, and determining a third characteristic point and a characteristic value according to the maximum amplitude.

In one possible embodiment, the blood pressure measuring device determines a final blood pressure value at the measurement location from the characteristic value and the raw blood pressure value, and the blood pressure measuring device determines a corresponding compensation factor from the characteristic value, wherein the compensation factor corresponding to the characteristic value is composed of two values corresponding to the diastolic pressure and the systolic pressure, respectively; the blood pressure measuring device determines a compensation value through the compensation coefficient and the original blood pressure value; the blood pressure measuring device determines a final blood pressure value of the measurement site from the compensation value and the original blood pressure value.

The original blood pressure value obtained by the original oscillography is compensated through the plurality of characteristic values, one or more aspects of the wearing degree, the artery position and the compression capacity of the air bag assembly are compensated, and the accuracy of blood pressure measurement is improved.

In one possible embodiment, the blood pressure measuring device determines the corresponding compensation factor from the characteristic value, including: the blood pressure measuring device determines different second compensation coefficients according to the different artery positions of the measuring part represented by the second characteristic value; and the blood pressure measuring device determines different third compensation coefficients according to different compression capacities of the air bag assembly represented by the third characteristic value.

Different compensation coefficients are set according to different states represented by the second characteristic value and the third characteristic value, and the accuracy of blood pressure calculation can be further improved. That is, for the second feature value, when the second feature value is smaller than the second feature lower threshold, the determined second compensation coefficient is x1_DBP,x1_SBP(ii) a When the second characteristic value is larger than the second characteristic upper threshold value, the second compensation coefficient is determined to be x2_DBP,x2_SBP(ii) a When the second feature value is between the second feature lower threshold and the second feature upper threshold, the second compensation coefficient is determined to be x3_DBP,x3_SBP. The specific values of the three sets of compensation coefficients may be set to be identical, partially identical or completely different. The determination of the third compensation coefficient corresponding to the third eigenvalue is the same as the determination of the second compensation coefficient, and is not described in detail.

Drawings

FIG. 1 is a schematic composition diagram of an embodiment of a blood pressure measuring device according to the present invention.

Fig. 2 is a schematic composition diagram of another embodiment of the blood pressure measuring device according to the present invention.

Fig. 3 is a schematic structural view of the blood pressure measuring device of the present invention worn on a measurement site.

Fig. 4 is a general flowchart of the measurement calculation method of the present invention.

FIG. 5 is a graph of the raw pressure signal of the present invention.

FIG. 6 is a graph of static pressure signals for the present invention.

FIG. 7 is a diagram of pulse signals according to the present invention.

FIG. 8 is a diagram showing the relationship between various data and formulas in the blood pressure measurement and calculation method of the present invention.

Fig. 9 is a flowchart illustrating a specific step of step S3 in the blood pressure measurement calculation method according to the present invention.

FIG. 10 is a graph showing the combination of the static pressure signal and the pulse wave signal when the blood pressure measuring device is applied with too tight a fitting force.

FIG. 11 is a graph showing the combination of static pressure signals and pulse wave signals with moderate fitting degree of the blood pressure measuring device.

FIG. 12 is a graph showing the combination of the static pressure signal and the pulse wave signal of the blood pressure measuring device with a loose fitting degree.

FIG. 13 is a graph showing the combination of the static pressure signal and the pulse wave signal of the blood pressure measuring device with too loose fitting.

Fig. 14 is a flowchart illustrating a specific step of step S32 in the blood pressure measurement calculation method according to the present invention.

FIG. 15 is a graph showing a combination of static pressure signals and pulse wave signals when the artery is shallow.

Fig. 16 is a graph showing a combination of the static pressure signal and the pulse wave signal in the case where the artery is deep.

Fig. 17 is a graph showing a combination of curves of the static pressure signal and the pulse wave signal in the case of a better compression ability.

Fig. 18 is a graph showing a combination of curves of the static pressure signal and the pulse wave signal in the case of the compression ability.

Fig. 19 is a flowchart illustrating a specific step of step S5 in the blood pressure measurement calculation method according to the present invention.

Fig. 20 is a flowchart illustrating a specific step of step S51 in the blood pressure measurement calculation method according to the present invention.

Fig. 21 is a flowchart illustrating a specific step of step S52 in the blood pressure measurement and calculation method according to the present invention.

Fig. 22 is a signal diagram of a specific application example in the present embodiment.

Reference numerals: 1. an airbag module; 2. a measurement site; 21. an artery; 3. and (4) a watchband.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

The oscillometric method measures blood pressure through pulse wave signals, determines average pressure Amplitude (ABP) in an amplitude curve of the pulse, and obtains an initial blood pressure value comprising initial diastolic pressure (DBP, diastolic pressure) and initial systolic pressure (SBP, systolic pressure) through a certain proportionality coefficient.

The initial blood pressure value is calculated as the following formula group (1):

A_SBP＝A_ABP*X_SBP

A_DBP＝A_ABP*X_DBP

wherein A is_ABPRepresenting the mean pressure amplitude, X, in the amplitude curve_SBPThe scale factor representing SBP may be set to 0.4-0.6, X_DBPThe scaling factor, which represents DBP, can be set to 0.3-0.5, A_DBPRepresenting the amplitude, A, corresponding to the DBP on the calculated amplitude curve_SBPRepresenting the amplitude, DBP, corresponding to the SBP on the calculated amplitude curve₀Is the initial DBP, is A_DBPThe pressure value corresponding to the static pressure signal at the time point; in the same way, SBP₀Is the initial SBP, is A_SBPThe pressure value corresponding to the static pressure signal at the time point.

Fig. 1 is a schematic composition diagram of an embodiment of the blood pressure measuring device according to the present invention, which includes a central processor, a storage module, an air pump control module, an air pump, a pressure sensor, an air valve assembly, and an air bag assembly 1 communicated with the air valve assembly. The central processor, the storage module, the pressure sensor, the air pump control module, the air pump and the air valve assembly can be connected through communication lines, and the air pump, the pressure sensor, the air valve assembly and the air bag assembly 1 are communicated with one another through a guide pipe or an air vent to form a circulation air passage for air circulation, so that the purpose of measuring blood pressure is achieved.

In this embodiment, the central processor is used for controlling and processing information, and is responsible for detecting signals and controlling other modules.

The storage module is used for storing data and threshold values needed in the blood pressure measurement and calculation process, and the data and the threshold values include but are not limited to a first characteristic lower threshold value, a first characteristic upper threshold value, a second characteristic lower threshold value, a second characteristic upper threshold value, a third characteristic lower threshold value, a third characteristic upper threshold value, a first amplitude threshold value, a preset pressure threshold value and the like. The threshold mentioned and applied in this embodiment is obtained by analyzing and integrating pressure signals obtained in multiple historical blood pressure measurement processes, and is an information processing method known to those skilled in the art, and is not described herein again.

The air pump control module is used for controlling the process of inflating the air pump and the air valve component to the air bag component 1, in the embodiment, the air pump, the air valve component, form the circulation air flue that circulates each other between air bag component 1 and the pressure sensor, be equipped with the gasbag of more than one quantity in the air bag component 1, when gasbag quantity is greater than 1, need control the opening and closing of the air flow channel between air pump and the different gasbags through the air valve component, the connection of air valve component and air bag component 1 can change to some extent because of the number of gasbag, for uncertain connection relation, therefore in fig. 1, between air valve component and the air bag component 1, and adopt the dotted line to connect between air bag component 1 and the pressure sensor and represent.

As shown in fig. 2, in another embodiment of the blood pressure measuring device, the air bag module 1 uses a certain number of one, and the air valve module is not needed, so that the air pump and the air bag module 1, and the communication air passage between the air bag module 1 and the pressure sensor are determined and represented by solid line connection.

The blood pressure measurement calculation method of the present embodiment is described in detail below with reference to the drawings. FIG. 4 is a flow chart of a blood pressure measuring method, which includes the following steps S1-S5.

And S1, controlling the air pump to inflate the air bag module 1, and continuously detecting a pressure signal in the air bag module 1 during the inflation process.

The user wears the blood pressure measuring device so that the air bag module 1 is close to the measurement portion 2, as shown in fig. 3, the measurement portion 2 in this embodiment is the wrist of the user, and particularly the wrist is on the same side as the palm, i.e. on the side close to the radial artery 21. In the measurement process, the air pump control module controls the air pump to inflate the air bag assembly 1 to expand the air bag assembly 1, the air bag assembly 1 pressurizes the wrist, and the pressure sensor can detect the pressure value of the wrist radial artery 21 by acquiring the pressure value in the air bag assembly 1, so that the blood pressure measurement is realized.

And S2, acquiring a pulse wave signal and a static pressure signal according to the pressure signal.

In the actual measurement process of step S1, the pressure signal, which is the pressure rising curve of the airbag module 1 obtained by the pressure sensor, is the raw pressure signal detected by the pressure sensor, as shown in fig. 5, and the raw pressure signal is composed of the direct current pressure (static pressure signal) and the alternating current pulse signal (pulse wave signal). In step S2 of the present embodiment, the blood pressure measuring apparatus separates the static pressure signal and the pulse wave signal from each other by butterworth filtering or wavelet filtering, and the two separated signal curves are respectively shown in fig. 6 and 7.

In the original pressure signal, the first half of the signal curve has almost no pulse oscillations, since there is a certain difference between the pressure in the balloon assembly 1 and the pressure value of the radial artery 21 of the wrist. Along with the pressure gradually increases, the pressure effect is generated on the radial artery 21, the pulse oscillation is more and more obvious, the pulse oscillation amplitude is maximum until the pressure in the air bag component 1 is equal to the pressure applied to the radial artery 21, and finally the pulse oscillation is gradually weakened until the pulse oscillation disappears along with the continuous increase of the pressure applied to the radial artery 21. FIG. 6 is a static pressure portion of the pressure signal for a more accurate pressure value; fig. 7 is a pulse wave signal curve, and a pulse amplitude variation curve is arranged above the pulse wave oscillation curve, so that the oscillation intensity of the pulse can be shown to be changed into a rule that the oscillation intensity is gradually increased and then gradually reduced along with the increase of the external applied pressure, and the basic rule of measuring the blood pressure by an oscillometric method is met.

And S3, determining at least one characteristic value through the pressure signal.

In step S3, the characteristic value may be determined from the pressure signal, or may be determined from information carried in the pulse wave signal, and the meanings of the characteristic values determined from the two different signals are different.

As shown in fig. 9, step S3 includes:

and S311, determining a first characteristic point and a first characteristic value through the static pressure signal.

And S312, judging whether the blood pressure measuring device is properly attached to the measuring part 2 or not according to the first characteristic point and the first characteristic value.

When the fit between the blood pressure measuring device and the measuring part 2 is determined to be moderate, the inflation is continued to measure the blood pressure, and the step S32 is carried out; if it is determined that the blood pressure measurement device and the measurement site 2 are excessively attached, the flow proceeds to step S33 where the air pump is controlled to stop the inflation.

In this embodiment, the whole inflation process is divided into a first inflation stage and a second inflation stage through the first characteristic point, and the first characteristic point are mainly used for testing and judging the fitting degree of the blood pressure measuring device and the measuring part 2 so as to judge whether further inflation and measurement are needed or not and ensure the accuracy of a final blood pressure value obtained after further inflation measurement.

As shown in fig. 9 to 12, different wearing conditions have different effects on the pulse wave. Fig. 11 is a graph combining static pressure signals and pulse wave signals with moderate fitting degree of the blood pressure measuring device, which is a reference sample during signal processing, the air bag component 1 does not exert force on the wrist in the early stage of inflation, but gradually presses the wrist in the pressurizing process, and actually, the pressure of the air in the air bag is relatively close to the pressure on the wrist.

FIG. 10 is a static pressure signal of blood pressure measuring device with too tight fittingThe graph of the horn and the pulse wave signal is combined, and when the user wears the blood pressure measuring device, the case shown in fig. 10 occurs when the band 3 is tightened too much. At the beginning of the initial period when the air pump starts to inflate, the air bag component 1 exerts a force on the wrist, and the compression efficiency of the air bag component 1 on the measurement part 2 is improved. Relative to the graph of fig. 11, the actual pressure of the gas in the airbag module 1 is lower than the pressure experienced by the wrist (measurement site 2), resulting in a leftward shift of the pressure curve as a whole, a decrease in the average pressure, and an initial DBP₀With the initial SBP₀And also decreases.

As the fitting degree is gradually relaxed, as shown in fig. 12 and 13, the wrist portion needs to be fitted by inflating and pressurizing the air bag in the early stage, and the pressure loss consumed in this part causes the pressure in the actual air bag to be greater than the pressure applied to the wrist portion, so that the whole body moves to the right, and finally the pressure value obtained by the test is higher.

In combination with the above analysis, it can be seen that when the fit is not within the moderate range, the initial pressure value, i.e., DBP, is calculated₀And SBP₀The deviation from the blood pressure value measured after being worn correctly is large.

In this embodiment, the first characteristic point is a point when the pressure value of the static pressure signal reaches the preset pressure threshold, the first characteristic value is an average rate when the pressure value reaches the preset pressure threshold, the average rate is obtained by calculating the pressure value and the time to reach the pressure value, and the formula is as follows:

F1＝P1/T1

wherein F1 represents the first characteristic value, i.e. the average speed of the pressure reaching the preset pressure threshold, P1 represents the preset pressure threshold corresponding to the first characteristic point, and through tests, the preset pressure threshold can be set to be 25-55mmhg, and T1 is the time when the pressure reaches P1.

That is, in step S312, it is determined whether F1 is within the appropriate section, and if so, the process proceeds to step S32.

In step S32, when a stable initial pulse wave signal appears in the pressure signal detected by the blood pressure measurement device, a second feature point and a second feature value for determining the depth of the artery 21 at the measurement site 2 are acquired.

As shown in fig. 14, step 32 includes:

s321, judging whether stable pulse wave initial signals appear in the pulse waves.

And S322, determining a second characteristic point and a second characteristic value according to the stable initial signal.

As shown in fig. 15 and 16, the pulse waves measured by different users may also be different, and the difference in the depth of the artery 21 of each user may also affect the measurement result deviation of the blood pressure. FIG. 15 is a graph showing the combination of the static pressure signal and the pulse wave signal under the condition of a shallow artery 21, wherein a stable pulse wave appears in the early inflation stage (within 5-10 s), and the corresponding pressure value is within 50 mmhg. FIG. 16 is a graph showing the combination of the static pressure signal and the pulse wave signal under the condition of a deeper artery 21, and a more stable pulse wave appears within 10-15s of the inflation time, and the corresponding pressure value is within the range of 50-100 mmhg. As can be seen from fig. 13 and 14, there is a large difference in ABP between them, and the ABP offset is higher when the artery 21 is deeper. Accordingly, a corresponding computational compensation of the situation of the position of the artery 21 of different users is required to ensure a more accurate blood pressure value.

In step S321, a characteristic condition may be set, and when 5 pulse waves continuously appear in the pulse wave signal, amplitudes of the 5 pulse waves are all greater than the preset amplitude 10, and a difference between the amplitudes is all less than 2, it is determined that the pulse wave initial signal appears in the pressure signal.

In the present embodiment, the second characteristic point is a point at which the pulse wave initial signal appears, and the second characteristic value (F2) may be a time (T2) at which a stable pulse wave signal appears, or may be a pressure value (P2) corresponding to when a stable pulse wave signal appears, that is, F2 equals T2 or F2 equals P2.

In the present embodiment, as shown in fig. 14, step S32 further includes

S323, judging whether the pulse wave signal reaches a first amplitude threshold value.

In the actual measurement process, the first amplitude threshold in S323 may be the maximum amplitude in the pulse wave amplitude curve, or may be a factor times the maximum amplitude. In this embodiment, the coefficient may be set between 0.3 and 0.7.

And S324, determining a third characteristic value and a third characteristic point through the first amplitude threshold value.

As shown in fig. 17 and 18, in practice the compression capacity of the balloon assembly 1 against the radial artery 21 of the wrist is not completely uniform. The oppression ability can produce tiny displacement or deformation along with the gaseous volume grow in the gasbag, leads to the pressure that actually oppresses in the wrist to be less than the actual pressure in the gasbag subassembly 1, makes whole skew right at last, and the pressure value is on the high side. Fig. 17 is a graph combining the static pressure signal and the pulse wave signal under the condition of better compression ability, and the rising process and the falling process of the pulse wave amplitude under the normal condition are more obvious. As shown in fig. 18, which is a graph combining curves of the static pressure signal and the pulse wave signal under the condition of the compression capability, the pulse wave amplitude shows an ascending process without a descending process along with the increase of the pressure, and the pulse oscillation amplitude maintains a substantially stable state after rising to a certain amplitude, thereby causing measurement deviation. As can be seen from fig. 17 and 18, the ABP of the two is greatly different, and the ABP offset is higher in the case of weaker compression capability. Accordingly, a corresponding computational compensation of the compression capacity of the air bag module 1 is required to ensure a more accurate blood pressure value.

In this embodiment, the third characteristic point is a point when the pulse wave amplitude reaches the first amplitude threshold in the rising period, and the third characteristic value (F3) may be a time (T3) when the pulse wave amplitude reaches the first amplitude threshold, or may be a pressure value (P3) when the pulse wave amplitude reaches the first amplitude threshold, that is, F3 ═ T3 or F3 ═ P3.

And S4, determining an original blood pressure value through the pulse wave signal.

The original blood pressure value is determined by adopting a conventional means of measuring blood pressure by an oscillometric method, and the specific method is to obtain the initial DBP and the initial SBP by adopting a proportionality coefficient.

After determining the initial DBP and the initial SBP, recording the corresponding time of the initial DBP and the initial SBP on the time axis, i.e. P, according to the positions of the initial DBP and the initial SBP_DBPAnd P_SBP。

And S5, determining the final blood pressure value of the measuring part 2 according to the characteristic value and the original blood pressure value.

As shown in fig. 19, step S5 further includes:

and S51, determining a corresponding compensation coefficient according to the characteristic value, wherein the compensation coefficient corresponding to the characteristic value is composed of two values respectively corresponding to the diastolic pressure and the systolic pressure.

And S52, the blood pressure measuring device determines a compensation value through the compensation coefficient and the original blood pressure value.

S53, the blood pressure measuring device determines a final blood pressure value at the measurement site 2 from the compensation value and the original blood pressure value.

In step S51, the method includes:

and S511, the blood pressure measuring device determines a first compensation coefficient according to the first characteristic value.

Wherein the first compensation factor comprises s1_DBPAnd s1_SBP，s1_DBPAnd s1_SBPThe first characteristic value corresponds to a first compensation coefficient of the DBP and the SBP respectively.

S512, the blood pressure measuring device determines the same or different second compensation coefficients according to the different positions of the artery 21 of the measuring part 2 represented by the second characteristic value.

In this embodiment, when the second feature value is greater than the second upper feature threshold or the second feature value is less than the second lower feature threshold, the artery 21 of the measurement site 2 is located deeper or shallower; the artery 21 of the measurement site 2 is moderately located when the second feature value is between the second lower feature threshold and the second upper feature threshold.

Wherein the second compensation factor comprises s2_DBPAnd s2_SBP，s2_DBPAnd s2_SBPThe second characteristic value corresponds to a second compensation coefficient of the DBP and the SBP respectively. The second compensation coefficient has different sets of values depending on the degree of difference in the depth of the artery 21.

S513, the blood pressure measuring device determines the same or different third compensation coefficients according to the different compression capacities of the air bag assembly 1 represented by the third characteristic values.

In this embodiment, when the third characteristic value is smaller than the third characteristic lower threshold, the compression capability of the airbag module 1 is low; when the third characteristic value is greater than a third characteristic upper threshold value, the compression capacity of the airbag module 1 is higher; the compression capacity of the airbag module 1 is moderate when the third characteristic value is between the third characteristic lower threshold value and the third characteristic upper threshold value.

Wherein the third compensation factor comprises s3_DBPAnd s3_SBP，s3_DBPAnd s3_SBPThe third characteristic value corresponds to a third compensation coefficient of the DBP and the SBP respectively. The third compensation coefficient is provided with different value groups according to different compression capacities of the airbag module 1.

The relationship between the respective data and the formulas in the blood pressure measurement calculation method of the present embodiment is further described with reference to fig. 8 to 19.

In step S52, the method includes:

and S521, determining a first compensation value according to the first characteristic value and the second characteristic value.

Since the fitting degree of the blood pressure measuring device wearing during the early stage of inflation and the early stage of occurrence of pulse wave signals affects the compression degree of the artery 21 of the measurement part 2 by the subsequent air bag module 1, the first characteristic value and the second characteristic value need to be combined to determine the first compensation value.

Wherein the first compensation value comprises a first systolic pressure compensation value and a first diastolic pressure compensation value.

When the first compensation value is calculated, if the parameters selected by the second characteristic value are different, the compensation method is also different.

If the second characteristic value is the pressure value (P2), the first compensation value is calculated using the following equation set (2):

compensate1_SBP＝F1*s1_SBP+(F2-DBP₀)*st2_SBP

compensate1_DBP＝F1*s1_DBP+(F2-DBP₀)*st2_DBP

if the second characteristic value is a time value (T2), the first compensation value is calculated using the following equation set (3):

compensate1_SBP＝F1*s1_SBP+(F2-P_SBP)*sp2_SBP

compensate1_DBP＝F1*s1_DBP+(F2-P_DBP)*sp2_DBP

in the above two sets of equations, complenate 1_SBPIs the first systolic pressure compensation value, compensate1_DBPThe first diastolic compensation value. st2_DBPAnd st2_SBPRespectively corresponding the DBP and SBP to the compensation coefficients of the second characteristic value when the pressure value is adopted by the second characteristic value; sp2_DBPAnd sp2_SBPAnd respectively corresponding the DBP and the SBP to the compensation coefficients of the second characteristic value when the time value is adopted for the second characteristic value.

And S522, determining a second compensation value according to the third characteristic.

As the pressure increases, the volume of the gas in the airbag module 1 gradually increases, which may cause deformation or position, resulting in a higher pressure value, and the diastolic pressure DBP is substantially in the first half and is less affected by the later stage, so that the systolic pressure SBP needs to be compensated for a second time, i.e. the second compensation value in step S522 includes a second systolic pressure compensation value.

If the third characteristic value is the pressure value (P3), calculating a second systolic pressure compensation value using the following equation (4):

compensate2＝c+(F3-DBP₀)*st3_DBP+(SBP₀-F3)*st3_SBP

where the compensate2 is the second systolic pressure compensation value and c is a constant term, a more suitable value can be obtained by linear fitting of the test data. st3_DBPAnd st3_SBPAnd respectively corresponding the DBP and the SBP to the compensation coefficients of the third characteristic value when the pressure value is adopted for the third characteristic.

If the third characteristic is a time value (T3), then the second systolic pressure compensation value is calculated using the following equation (5):

compensate2＝c+(F3-P_DBP)*sp3_DBP+(P_SBP-F3)*sp3_SBP

wherein, compensate2 is the second contractionThe pressure compensation value c is a constant term, and a more appropriate value can be obtained through linear fitting of test data. sp3_DBPAnd sp3_SBPAnd respectively corresponding the DBP and the SBP when the time value is adopted for the third characteristic to the compensation coefficient of the third characteristic value.

In step S53, the final blood pressure value is determined using the following formula set (6),

SBP＝SBP_O+compensate1_SBP+compensate2

DBP＝DBP₀+compensate1_DBP

wherein SBP is the final systolic pressure obtained, and DBP is the final diastolic pressure calculated by measurement.

Next, an application example of the measurement example will be described with reference to fig. 17, where the blood pressure standard values in fig. 17 are SBP 112 and DBP 67.

In fig. 20, the linear curve sloping upward is the static pressure signal extracted from the original pressure signal; the signal with oscillation fluctuation is a pulse wave signal extracted from the original pressure signal; the third is a pulse wave amplitude envelope curve which is obtained by fitting according to the change of the pulse wave amplitude.

As can be seen from the figure, the average pressure value point is the middle point on the static pressure signal curve, and the average pressure value is 134.5 mmhg. The initial calculation yielded an SBP of 149.23mmhg and a DBP of 84.97mmhg, which overall shifted upwards making the blood pressure values higher compared to the standard SBP and standard DBP.

Then, by extracting the feature value, the first feature rate F1 is 5.856; the second characteristic value adopts a pressure value (F2) of 68; the third characteristic value employed a pressure value (F3) of 108.73 mmhg. The compensation value is calculated as: compact 1_SBP＝-16；compensate1_DBP＝-17；compensate2＝-20。

After correction, the blood pressure value calculated finally is: SBP 113; DBP 68.

Compared with the standard blood pressure value, the deviation is obviously reduced, and more accurate blood pressure value reading is obtained.

The foregoing is a preferred embodiment of the present invention, and it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit of the invention, and these should be considered to be within the scope of the invention.

Claims

1. A blood pressure measurement and calculation method is characterized in that: the method is applied to a blood pressure measuring device which comprises an air bag assembly and an air pump, and comprises the following steps:

the blood pressure measuring device controls the air pump to inflate the air bag assembly and continuously detects a pressure signal in the air bag assembly in the inflating process;

the blood pressure measuring device obtains a pulse wave signal and a static pressure signal through the pressure signal;

the blood pressure measuring device determines at least one characteristic value through the pressure signal;

the blood pressure measuring device determines an original blood pressure value through the pulse wave signal;

the blood pressure measuring device determines a final blood pressure value of the measurement part according to the characteristic value and the original blood pressure value.

2. A blood pressure measurement and calculation method according to claim 1, characterized in that:the blood pressure measuring device passes through Determining at least one characteristic value from the pressure signalComprises that

The blood pressure measuring device determines a characteristic value through the static pressure signal,or

The blood pressure measuring device determines a characteristic value through the pulse wave signal.

3. A blood pressure measurement and calculation method according to claim 1, characterized in that:the blood pressure measuring device passes through Determination of characteristic values for static pressure signalsComprises that

The inflation process of the air pump to inflate the air bag component by the blood pressure measuring device comprises a first inflation stage and a second inflation stage;

the blood pressure monitoring device obtains a first characteristic point and a first characteristic value for judging the fitting degree of the blood pressure measuring device and the measuring part through a static pressure signal in a pressure signal of a first inflation stage;

when the first characteristic value is larger than a first characteristic upper threshold value or the first characteristic value is smaller than a first characteristic lower threshold value, the blood pressure measuring device is excessively attached to the measuring part; when the first characteristic value is between the first characteristic lower threshold value and the first characteristic upper threshold value, the blood pressure measuring device is moderately attached to the measuring part.

4. A blood pressure measurement and calculation method according to claim 1, characterized in that:the blood pressure measuring device passes through Determining characteristic values of pulse wave signalsComprises that

When stable initial pulse wave signal appears in the pressure signal detected by the blood pressure measuring deviceAcquiring a second characteristic point and a second characteristic value for judging the depth of the position of the artery of the measurement part;

wherein the artery position of the measurement site is deeper or shallower when the second feature value is greater than a second upper feature threshold or the second feature value is less than a second lower feature threshold; the arterial location of the measurement site is moderate when the second feature value is between the second lower feature threshold and the second upper feature threshold.

5. A blood pressure measurement and calculation method according to claim 1, characterized in that:the blood pressure measuring device passes through Determining characteristic values of pulse wave signalsAnd also comprises

When the amplitude of the pulse wave signal reaches a first amplitude threshold value, the blood pressure measuring device obtains a third characteristic point and a third characteristic value for judging the compression capacity of the air bag assembly;

when the third characteristic value is smaller than a third characteristic lower threshold value, the compression capacity of the air bag component is lower; when the third characteristic value is larger than a third characteristic upper threshold value, the compression capacity of the air bag component is higher; the compression capability of the airbag assembly is moderate when the third characteristic value is between the third lower characteristic threshold and the third upper characteristic threshold.

6. A blood pressure measurement and calculation method according to claim 3, characterized in that:the blood pressure measuring device controls the air pump The inflation process for inflating the airbag assembly comprises a first inflation phase and a second inflation phase;

in the inflation process, a first inflation stage is performed before the static pressure signal reaches a preset pressure threshold, and the first characteristic point is a point when the static pressure signal reaches the preset pressure threshold;

when the blood pressure measuring device is moderately attached to the measuring part, the blood pressure measuring device controls the inflation process to enter a second inflation stage; and when the blood pressure measuring device is excessively attached to the measuring part, the blood pressure measuring device finishes inflating and stops measuring.

7. The blood pressure measurement calculation method according to claim 4, characterized in that:detected by the blood pressure measuring device When stable initial pulse wave signal appears in pressure signalComprises that

When n pulse waves continuously appear in the pulse wave signal, the amplitude values of the n pulse waves are all larger than the preset amplitude value, and the difference value between the amplitude values is smaller than m, a stable initial pulse wave signal appears in the pressure signal.

8. The blood pressure measurement calculation method according to claim 5, characterized in that:the first amplitude threshold valueIs determined by the maximum amplitude in the pulse wave signal detected by the blood pressure measuring device.

9. The blood pressure measurement calculation method according to any one of claims 3 to 8, characterized in that:the blood pressure measurement The device determines the final blood pressure value of the measuring part by the characteristic value and the original blood pressure valueComprises that

The blood pressure measuring device determines a corresponding compensation coefficient through the characteristic value,wherein the compensation coefficient corresponding to the characteristic value is composed of two values respectively corresponding to diastolic pressure and systolic pressure；

The blood pressure measuring device determines a compensation value through the compensation coefficient and the original blood pressure value;

the blood pressure measuring device determines a final blood pressure value of the measurement site from the compensation value and the original blood pressure value.

10. A blood pressure measurement and calculation method according to claim 9, wherein:the blood pressure measuring device passes through The characteristic values determine the corresponding compensation factors,the method comprises the following steps:

the blood pressure measuring device determines the same or different second compensation coefficients according to the different artery positions of the measuring part represented by the second characteristic value;

the blood pressure measuring device determines the same or different third compensation coefficients according to different compression capacities of the air bag assembly represented by the third characteristic value.