CN110840427A

CN110840427A - Continuous blood pressure measuring method, device and equipment based on volume pulse wave signals

Info

Publication number: CN110840427A
Application number: CN201911024345.XA
Authority: CN
Inventors: 李振齐; 鄢聪; 赵巍
Original assignee: Guangzhou Shiyuan Electronics Thecnology Co Ltd
Current assignee: Guangzhou Shiyuan Electronics Thecnology Co Ltd
Priority date: 2019-10-25
Filing date: 2019-10-25
Publication date: 2020-02-28

Abstract

The embodiment of the application provides a continuous blood pressure measuring method, a device, equipment and a storage medium based on volume pulse wave signals, wherein the method comprises the following steps: acquiring a volume pulse wave signal of an object to be detected; wherein, the volume pulse wave signal at least comprises a pulse wave period; obtaining a blood pressure characteristic value according to the period value of each pulse wave in the volume pulse wave signal and the amplitude change value of the pulse wave from the starting point of each pulse wave period to preset time; and inputting the blood pressure characteristic value into a pre-trained linear blood pressure model of the object to be detected to obtain the blood pressure value of the object to be detected. According to the method, the blood pressure is measured without waiting for inflation and deflation of the cuff in a cuff type blood pressure measuring method, so that the practical application is facilitated, and the continuous measurement of the blood pressure is realized; and the blood pressure characteristic value simultaneously utilizes the amplitude information and the wave velocity information of the volume pulse wave signal, so that the accuracy of blood pressure measurement is improved, the calculation of a linear blood pressure model is simple, and the efficiency of blood pressure measurement is improved.

Description

Continuous blood pressure measuring method, device and equipment based on volume pulse wave signals

Technical Field

The embodiment of the application relates to the field of blood pressure detection, in particular to a continuous blood pressure measuring method, device, equipment and storage medium based on volume pulse wave signals.

Background

Blood pressure is an important physiological parameter of a human body, can reflect cardiovascular function conditions of the human body, and is an indispensable part in personal health management. In recent years, the incidence of hypertension in people is increasing, and complications such as heart disease and stroke are often caused, which seriously threatens human health.

In the process of implementing the invention, the inventor finds that the following problems exist in the prior art: the traditional non-invasive blood pressure measuring method can be divided into a cuff type and a cuff-free type; the cuff type blood pressure measuring method has the advantage of high measuring accuracy, but continuous blood pressure detection cannot be realized and the cuff type blood pressure measuring method is inconvenient to use for a long time because the blood pressure measurement needs to be carried out in a cuff inflation and deflation mode; the cuff-free blood pressure measurement method needs to establish a blood pressure model, the process of establishing the blood pressure model is complex, and the accuracy rate of blood pressure measurement by the blood pressure model is not high. Therefore, it is important to develop a continuous and accurate blood pressure detection method.

Disclosure of Invention

In order to overcome the problems in the related art, the application provides a continuous blood pressure measuring method, a device, equipment and a storage medium based on volume pulse wave signals, which do not need to wait for cuff inflation and deflation to measure the blood pressure like a cuff type blood pressure measuring method, greatly facilitates the practical application and realizes the continuous measurement of the blood pressure; and the blood pressure characteristic value simultaneously utilizes the amplitude information and the wave velocity information of the volume pulse wave signal, so that the accuracy of blood pressure measurement is improved, the calculation of a linear blood pressure model is simple, and the efficiency of blood pressure measurement is improved.

According to a first aspect of embodiments of the present application, there is provided a continuous blood pressure measurement method based on a volume pulse wave signal, including the steps of:

acquiring a volume pulse wave signal of an object to be detected; wherein, the volume pulse wave signal at least comprises a pulse wave period;

obtaining a blood pressure characteristic value according to the period value of each pulse wave in the volume pulse wave signal and the amplitude change value of the pulse wave from the starting point of each pulse wave period to preset time;

and inputting the blood pressure characteristic value into a pre-trained linear blood pressure model of the object to be detected to obtain the blood pressure value of the object to be detected.

According to a second aspect of embodiments of the present application, there is provided a continuous blood pressure measurement device based on a volume pulse wave signal, including:

the signal acquisition module is used for acquiring a volume pulse wave signal of the object to be detected; wherein, the volume pulse wave signal at least comprises a pulse wave period;

the blood pressure characteristic value determining module is used for obtaining a blood pressure characteristic value according to the cycle value of each pulse wave in the volume pulse wave signal and the amplitude change value of the pulse wave from the starting point of each pulse wave cycle to preset time;

and the blood pressure value determining module is used for inputting the blood pressure characteristic value into a pre-trained linear blood pressure model of the object to be detected to obtain the blood pressure value of the object to be detected.

According to a third aspect of embodiments of the present application, there is provided an electronic apparatus, including: a processor and a memory; wherein the memory stores a computer program adapted to be loaded by the processor and to perform any of the above-mentioned continuous blood pressure measurement methods based on volume pulse wave signals.

According to a fourth aspect of embodiments of the present application, there is provided a computer-readable storage medium having stored thereon a computer program which, when being executed by a processor, implements the method for continuous blood pressure measurement based on volume pulse wave signals as set forth in any one of the above.

According to the embodiment of the application, the blood pressure characteristic value is obtained according to the period value of each pulse wave in the volume pulse wave signal and the amplitude change value of the pulse wave from the starting point of each pulse wave period to the preset time, then the blood pressure characteristic value is input into a linear blood pressure model of a pre-trained object to be measured, the blood pressure value of the object to be measured is obtained, the cuff-type blood pressure measurement method does not need to wait for inflation and deflation of a cuff to measure the blood pressure, the practical application is greatly facilitated, and the continuous measurement of the blood pressure is realized; and the blood pressure characteristic value simultaneously utilizes the amplitude information of the volume pulse wave signal and the wave velocity information represented by the period value, so that the accuracy of blood pressure measurement is improved, the calculation of a linear blood pressure model is simple, and the efficiency of blood pressure measurement is improved. Furthermore, by acquiring the average value of the ratio of the n-th power of each pulse amplitude variation value to the m-th power of the corresponding pulse wave period value as the blood pressure characteristic value, the detection error caused by movement or other reasons of the object to be detected just in the pulse wave period time can be prevented from influencing the accuracy of the subsequent measurement when a certain pulse wave period is used for analysis.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.

For a better understanding and practice, the invention is described in detail below with reference to the accompanying drawings.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic block diagram of an application environment of a continuous blood pressure measurement method based on a volume pulse wave signal according to an embodiment of the present application;

FIG. 2 is a flow chart of a method for continuous blood pressure measurement based on volume pulse wave signals according to an embodiment of the present application;

fig. 3 is a flowchart illustrating a training process of a blood pressure linear model of a subject to be tested according to an embodiment of the present application;

FIG. 4 is a flowchart illustrating a method for determining a period value of a pulse wave according to an embodiment of the present application;

FIG. 5 is a flowchart illustrating the method for determining the amplitude variation of the pulse wave according to the embodiment of the present application;

FIG. 6 is a flow chart illustrating the determination of a blood pressure characteristic according to an embodiment of the present application;

FIG. 7 is a schematic diagram illustrating the spatial length of the pulse wave in the blood vessel according to the embodiment of the present application;

FIG. 8 is a block diagram schematically illustrating a structure of a continuous blood pressure measuring device based on a volume pulse wave signal according to an embodiment of the present application;

FIG. 9 is a block diagram illustrating a structure of a blood pressure linear model training module according to an embodiment of the present application;

FIG. 10 is a block diagram schematically illustrating a structure of a pulse wave period value obtaining module according to an embodiment of the present application;

fig. 11 is a block diagram schematically illustrating a structure of a pulse wave amplitude variation value determination module according to an embodiment of the present application;

fig. 12 is a block diagram schematically illustrating a structure of a blood pressure feature value calculation module according to an embodiment of the present application;

fig. 13 is a block diagram schematically illustrating a structure of an electronic device according to an embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more clear, embodiments of the present application will be described in further detail below with reference to the accompanying drawings.

It should be understood that the embodiments described are only a few embodiments of the present application, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the application, as detailed in the appended claims.

In the description of the present application, it is to be understood that the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not necessarily used to describe a particular order or sequence, nor are they to be construed as indicating or implying relative importance. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate. As used in this application and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The word "if/if" as used herein may be interpreted as "at … …" or "when … …" or "in response to a determination". Further, in the description of the present application, "a plurality" means two or more unless otherwise specified. "and/or" describes the association relationship of the associated objects, meaning that there may be three relationships, e.g., a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship.

Please refer to fig. 1, which is a block diagram illustrating an application environment of a continuous blood pressure measurement method based on a volume pulse wave signal according to an embodiment of the present application.

As shown in fig. 1, the application environment of the continuous blood pressure measuring method based on the volume pulse wave signal includes an electronic device 1000, a volume pulse wave measuring device 2000, a blood pressure value measuring device 3000, and a display device 4000. The electronic device 1000 may have an application 1100 running thereon for applying the continuous blood pressure measurement method based on volume pulse wave signals according to the embodiment of the present application.

The electronic device 1000 may be any intelligent terminal, and may be embodied as a computer, a mobile phone, a tablet computer, an interactive smart tablet, a PDA (Personal Digital Assistant), an e-book reader, a multimedia player, and the like. The application 1100 may also be presented in other forms that are suitable for a different intelligent terminal. In some examples, the presentation may also be in the form of, for example, a system plug-in, a web plug-in, and the like.

The volume pulse wave measuring device 2000 is used for volume pulse wave signals of a subject to be measured to establish a blood pressure linear model and measure continuous blood pressure. The volume pulse wave measuring device 2000 may include a light source generating module for generating a light signal, an optical sensor module for collecting an optical signal fed back after the light signal passes through a human body, a signal processing module for processing the fed back optical signal, and the like. The signal processing module of the volume pulse wave measuring apparatus 2000 may be integrated as a component in the electronic device, or may be independent from the electronic device as an independent component with the light source generating module and the optical sensor module, and the volume pulse wave signal processed by the signal processing module is transmitted to the application program 1100 of the electronic device.

The blood pressure value measuring device 3000 is used for acquiring a real blood pressure value of a subject to be measured, and the blood pressure value may be systolic pressure, diastolic pressure, average pressure, or the like. When the volume pulse wave is measured, the blood pressure value measuring device 3000 measures the real blood pressure value of the object to be measured at the same time, and then transmits the blood pressure data corresponding to the volume pulse wave signal to the application program 1100 of the electronic device to establish a blood pressure linear model, that is, for different individual objects, the corresponding blood pressure linear models are different, and when continuous blood pressure measurement needs to be performed on different individual objects, the linear blood pressure models of different individual objects need to be established respectively. The blood pressure value measuring device 3000 may be an instrument that can accurately measure the actual blood pressure value of the object to be measured, such as a cuff inflatable electronic sphygmomanometer.

The display device 4000 is used for displaying the blood pressure value of the subject to be measured, which may be systolic pressure, diastolic pressure, average pressure, or the like, measured by the continuous blood pressure measurement method based on the volume pulse wave signal of the present application. The display device 4000 may be integrated as a component in the electronic device, or may be a separate component that displays the blood pressure value calculated by the application 1100 of the electronic device, independently of the electronic device.

Example 1

The embodiment of the application discloses a continuous blood pressure measuring method based on volume pulse wave signals, and the method is applied to electronic equipment.

A method for continuous blood pressure measurement based on volume pulse wave signals according to an embodiment of the present application will be described in detail with reference to fig. 2.

Referring to fig. 2, a method for continuous blood pressure measurement based on volume pulse wave signals according to an embodiment of the present application includes the following steps:

step S101: acquiring a volume pulse wave signal of an object to be detected; wherein the volume pulse wave signal at least comprises one pulse wave period.

The volume pulse wave signal may be a signal measured by photoplethysmography. The photoplethysmography (PPG) is a non-invasive detection method for detecting blood volume changes in living tissues by means of photoelectric means such as a volume pulse wave measurement device, and the specific principle is as follows: when a light source generation module of the volume pulse wave measuring device emits light beams with certain wavelengths to irradiate the skin surface, the light beams are transmitted to the optical sensor module in a transmission or reflection mode; in the process, the light intensity detected by the optical sensor module is weakened due to the absorption and attenuation effects of skin muscle tissues and blood; wherein the absorption of light by skin, muscle and tissue is constant throughout the blood circulation, while the volume of blood in the skin pulsates under the action of the systolic relaxation; when the heart contracts, the blood volume of the peripheral blood vessel is the maximum, the light absorption amount is also the maximum, and the detected light intensity is the minimum; when the heart is in diastole, on the contrary, the blood volume of peripheral blood vessels is the minimum, the detected light intensity is the maximum, and the light intensity detected by the optical sensor is in pulsatile change; the light intensity change signal is converted into an electric signal through a signal processing module, and the electric signal is amplified to obtain the change of volume pulse blood flow, namely a volume pulse wave signal. When the volume pulse wave signal is acquired, the measurement is performed without waiting for the inflation and deflation of the cuff like the cuff type blood pressure measurement method, so the volume pulse wave signal can be used for continuous blood pressure measurement to acquire a plurality of pulse waves.

Because the finger tip pulse wave reflects the general condition that the blood flows in the finger tip microcirculation, can evaluate cardiovascular function and microcirculation function to a certain extent through finger tip pulse wave, and the mode of finger tip is measured more conveniently moreover, consequently, in the embodiment of the application, measure the finger tip of the object to be measured through volume pulse wave measuring device to acquire volume pulse wave signals.

Step S102: and obtaining a blood pressure characteristic value according to the period value of each pulse wave in the volume pulse wave signal and the amplitude change value of the pulse wave from the starting point of each pulse wave period to preset time.

The volume pulse wave signal is a continuous waveform signal, which can be generally represented by a waveform diagram with the abscissa representing time and the ordinate representing the pulse wave amplitude. Since the acquired volume pulse wave signal generally includes a plurality of pulse waves, the period value of each pulse wave and the amplitude variation value of the pulse wave from the start point of each pulse wave period to a preset time can be acquired by identifying each position point of the volume pulse wave signal.

Specifically, the reciprocal of the period value of the pulse wave in the embodiment of the present invention corresponds to the wave velocity of the pulse wave, and indirectly reflects the change in the magnitude of the blood pressure, so that the accuracy of the blood pressure measurement can be improved by indirectly using the wave velocity information of the pulse wave signal.

Wherein, predetermine the time for a short period of time that deviates from the starting point, for example at the rising edge or the falling edge of pulse wave, in this application embodiment, the value range of predetermineeing the time can be 0.002 second-0.02 second, because this application embodiment sampling rate is 500HZ, for obtaining pulse wave variation value, it is more convenient to predetermine the time and take the value of 0.002 second, and under extreme condition, the pulse wave cycle is minimum 0.2s, takes the tenth of minimum pulse wave cycle to be 0.02 second, can ensure to obtain amplitude variation value at the rising edge of pulse wave, and through inventor's long-term experiment verification, above-mentioned value range can make follow-up measuring blood pressure more accurate.

The method mainly aims to obtain the amplitude change value of a period of time in a pulse wave period, theoretically, the length of the period of time can be selected according to needs, but the pulse wave starting point corresponds to the diastolic period of blood vessels, and blood vessel parameters are stable, so that the measured data can be more accurate by determining the amplitude change value in the period of time from the starting point to the preset time. In addition, the preset time of the application is 0.002-0.02 second, which is shorter, and the result of final measurement is more accurate because the shorter the time is, the smaller the change of the blood vessel parameters is. Step S103: and inputting the blood pressure characteristic value into a pre-trained linear blood pressure model of the object to be detected to obtain the blood pressure value of the object to be detected.

According to the embodiment of the application, the blood pressure characteristic value is obtained according to the period value of each pulse wave in the volume pulse wave signal and the amplitude change value of the pulse wave from the starting point of each pulse wave period to the preset time, then the blood pressure characteristic value is input into a linear blood pressure model of a pre-trained object to be measured, the blood pressure value of the object to be measured is obtained, the cuff-type blood pressure measurement method does not need to wait for inflation and deflation of a cuff to measure the blood pressure, the practical application is greatly facilitated, and the continuous measurement of the blood pressure is realized; and the blood pressure characteristic value simultaneously utilizes the amplitude information of the volume pulse wave signal and the wave velocity information represented by the period value, so that the accuracy of blood pressure measurement is improved, the calculation of a linear blood pressure model is simple, the efficiency of blood pressure measurement is improved, and the interpretability of the blood pressure measurement is improved. The interpretability is that when people need to know or solve a thing, enough understandable information can be obtained, a single blood pressure characteristic value which simultaneously covers amplitude information and wave velocity information is determined through formula derivation, the linear relation of the blood pressure characteristic value and blood pressure is clarified, and the linear relation is obtained through theoretical formula derivation determination instead of being trained through big data and related algorithms, so that the method has powerful theoretical support and powerful explanation; that is, the blood pressure measuring device improves the measuring precision, improves the blood pressure measuring efficiency and improves the interpretability.

Referring to fig. 3, in an exemplary embodiment of the present application, in step S103, the training process of the blood pressure linear model of the subject includes the following steps:

step S1031: acquiring at least two groups of volume pulse wave signals for training of a to-be-detected object and at least two corresponding groups of blood pressure values for training; wherein the blood pressure value is obtained by a cuff type blood pressure measuring mode; the volume pulse wave signal at least comprises one pulse wave period.

When the linear blood pressure model is trained, the blood pressure value obtained by adopting a cuff type blood pressure measurement mode is used as a training sample, so that the measured blood pressure value is more accurate, the linear blood pressure model is closer to an actual measurement value, and the accuracy of subsequent blood pressure measurement is improved.

The blood pressure value can be systolic pressure, diastolic pressure or average pressure, and correspondingly, the established linear blood pressure model is a linear blood pressure model based on systolic pressure, a linear blood pressure model based on diastolic pressure or a linear blood pressure model based on average pressure.

Step S1032: and obtaining at least two groups of blood pressure characteristic values according to the cycle value of each pulse wave in at least two groups of volume pulse wave signals and the amplitude change value of the pulse wave from the starting point of each pulse wave cycle to preset time.

Step S1033: and taking at least two groups of the blood pressure characteristic values as input, taking at least two groups of the corresponding blood pressure values as output, and calculating to obtain a linear blood pressure model.

For the linear blood pressure model, the expression is: p ═ a × F + b, where F denotes the blood pressure characteristic value and P denotes the blood pressure value; therefore, at least two sets of the blood pressure characteristic values and at least two corresponding sets of the blood pressure values are required to determine the parameter a and the parameter b, so as to determine the linear blood pressure model.

According to the method and the device, at least two groups of blood pressure characteristic values are obtained according to the period value of each pulse wave in at least two groups of volume pulse wave signals and the amplitude change value of the pulse wave from the starting point of each pulse wave period to the preset time, the blood pressure value is obtained in a cuff type blood pressure measuring mode, then the amplitude information of the volume pulse wave signals, the wave velocity information represented by the period value and the accurate blood pressure value are simultaneously utilized to establish a linear blood pressure model, and the accuracy of measuring the blood pressure by the linear blood pressure model is improved.

Since acquiring the volume pulse wave signal is easily affected by the surrounding environment, a measuring instrument, and the like, in an exemplary embodiment of the present application, the method for continuous blood pressure measurement based on the volume pulse wave signal further includes: preprocessing the volume pulse wave signals obtained in step S101 and step S1031; the pretreatment mode at least comprises one or more of the following modes: mean filtering, baseline drift removal, and high frequency noise removal. The mean filtering may adopt a filtering method such as a moving average filter. The method for removing the baseline drift and the high-frequency noise can adopt methods such as Gaussian filtering, frequency domain filtering, wavelet transformation and the like for processing. The influence of the surrounding environment, a measuring instrument and the like can be reduced as much as possible by preprocessing the volume pulse wave signal of the object to be measured, and the accuracy of subsequent blood pressure measurement is further improved.

Referring to fig. 4, in an exemplary embodiment of the present application, in step S102 and step S1032, the method further includes a step of determining a period value of the pulse wave, including:

step S10211: and acquiring the starting position and the end position of the pulse wave period, and calculating the number of sampling points between the starting position and the end position.

The initial position and the end position of the pulse wave period can be obtained by adopting a slope method to carry out first order differential solution on the volume pulse wave signal to obtain a unitary differential curve, the position of a zero crossing point is obtained by judging the change of the unitary differential curve and corresponds to the extreme position of the volume pulse wave, and the initial position and the end position of each pulse wave period are obtained by comparing the periodic change of the extreme position. In addition, the volume pulse wave signals may also be analyzed and extracted in the frequency domain using fourier transform or wavelet transform to obtain the start and end positions of each pulse wave period.

Step S10212: and determining the ratio of the number of the sampling points to the sampling rate of the volume pulse wave signal as the period value of the pulse wave.

Specifically, the calculation method of the period value of the pulse wave is as follows:

in the above formula, T_iA period value representing the ith pulse wave;

a sampling point number indicating the position of the start point of the ith pulse wave period, namely the position of the start point of the ith pulse wave period;

the sampling point sequence number of the terminal point position of the ith pulse wave period, namely the terminal point of the ith pulse wave period is represented;the number of sampling points representing the position from the starting point of the ith pulse wave period to the position from the ending point of the ith pulse wave period; f. of_sRepresenting the sampling rate of the volume pulse wave.

The period value of the pulse wave of the embodiment of the application can reflect the wave velocity of the pulse wave in the blood vessel to a certain extent, so that the change of the blood pressure is indirectly reflected, and therefore, the blood pressure linear model is established by obtaining the period value of the pulse wave, the wave velocity information of the pulse wave signal can be utilized, and the accuracy of blood pressure measurement is improved.

Referring to fig. 5, in an exemplary embodiment of the present application, the step S102 and the step S1032 further include the step of determining the amplitude variation value of the pulse wave, including:

step S10221: obtaining a pulse wave amplitude value corresponding to the starting point of a pulse wave period and a pulse wave amplitude value corresponding to preset time; the preset time is a short time period away from the starting point.

Step S10222: and determining the difference value between the pulse amplitude corresponding to the preset time and the pulse wave amplitude corresponding to the starting point as the amplitude change value of the pulse wave.

Specifically, the calculation method of the amplitude variation value of the pulse wave is as follows:

in the above formula,. DELTA.I_iRepresenting the amplitude change value of the pulse wave in the ith pulse wave period;

the pulse wave amplitude value corresponding to the starting point position in the ith pulse wave period is represented;

representing the pulse amplitude corresponding to the position of the preset time in the ith pulse wave period; Δ p is a short time from the starting point, and the preset time may range from 0.002 seconds to 0.02 seconds.

The amplitude change value of the pulse wave can reflect the radius change of the blood vessel to a certain extent, so that the change condition of the blood pressure is indirectly reflected, especially the amplitude change value of the pulse wave starting from the starting point, therefore, a blood pressure linear model is established by obtaining the amplitude change value of the pulse wave, and the accuracy of blood pressure measurement can be improved by utilizing the amplitude information of the pulse wave signal.

Referring to fig. 6, in an exemplary embodiment of the present application, in step S102 and step S1032, the method further includes a step of determining the blood pressure characteristic value, including:

step S10231: calculating the ratio of the n power of the pulse amplitude variation value in each pulse wave period to the m power of the corresponding pulse wave period value; wherein n and m are positive numbers.

Step S10232: and accumulating the ratio values and averaging to obtain an average value, and determining the average value as a blood pressure characteristic value.

Specifically, the calculation formula of the blood pressure characteristic value is represented as:

in the above formula, F represents a blood pressure characteristic value of the volume pulse wave signal; n represents the number of pulse waves in the volume pulse wave signal; delta I_iA pulse amplitude variation value representing the ith pulse wave; t is_iThe pulse wave period value of the ith pulse wave is shown.

By obtaining the average value of the ratio of the n-th power of each pulse amplitude variation value to the m-th power of the corresponding pulse wave period value as the blood pressure characteristic value, the detection error caused by movement or other reasons of the object to be detected just in the pulse wave period time can be prevented from influencing the accuracy of the subsequent measurement when a certain pulse wave period is used for analysis independently.

In the embodiment of the present application, preferably, n is 1, and m is 2, that is, the calculation formula of the blood pressure characteristic value is preferably:

the accuracy of blood pressure measurement can be improved by obtaining the blood pressure measurement value through the preferable blood pressure characteristic value.

In order to enable the established linear blood pressure model to be more accurate and reflect actual blood pressure measurement, the linear blood pressure model can be obtained through least square calculation. Specifically, the blood pressure characteristic value is used as an abscissa, the blood pressure value is used as an ordinate to establish a direct coordinate system, then a plurality of groups of blood pressure characteristic values and corresponding blood pressure values are used as a coordinate point to be calibrated on the coordinate system, a straight line is used for fitting the coordinate points, the sum of squares of residuals of the straight line and the sample point is reduced by adjusting parameters of the straight line, and finally the straight line with the minimum sum of squares of the residuals is determined as the linear blood pressure model.

The principle of the continuous blood pressure measurement method based on the volume pulse wave signal according to the present invention will be described in detail below.

Referring to fig. 7, according to the assumption that the pulse wave space length is constant, the relationship between the blood flow velocity and the pulse wave period can be obtained as follows:

in the above formula, v represents the blood flow rate; l is_TRepresenting the spatial length of the pulse wave; t represents a period value of the pulse wave.

The flow rate formula of the ideal liquid in the elastic tube is as follows:

in the above formula, v represents the blood flow rate; e represents the Young's modulus of the blood vessel; ρ represents a blood density; h represents the thickness of the vessel wall; r represents the vessel radius.

The expression of young's modulus E can be obtained from the above formula (1) and formula (2) as follows:

according to the Young's modulus formula:

the relationship between the circumference and the radius of the blood vessel is as follows: l-2 pi r and variable quantity formula delta L-L of blood vessel perimeter under influence of external force₀＝2π(r-r₀) Obtaining the relationship between the Young modulus E of the blood vessel and the radius r of the blood vessel:

in the above formula, E represents the young's modulus of the blood vessel; p_cRepresenting the circumferential stress to which the blood vessel is subjected; r is₀Represents the radius of the blood vessel when not affected by an external force; l is₀Representing the circumference of the blood vessel when unaffected by external forces; Δ L represents the amount of change in the circumference of the blood vessel under the influence of an external force; r represents the vessel radius.

The circumferential stress P borne by the blood vessel can be obtained by the formula (3) and the formula (4)_cThe expression of (a) is as follows:

since the blood vessel can be regarded as a thin-walled tube, the inner wall pressure (i.e., blood pressure value) P and the circumferential stress P to which the blood vessel is subjected_cThe relation of (A) is as follows:

the blood pressure value P can be obtained from the equations (5) and (6) by the following calculation:

the difference calculation of equation (7) can obtain the blood pressure change value Δ P in the following manner:

according to the Lambert-Beer law, the variation Δ V of the blood volume in the blood vessel and the variation Δ I of the output voltage of the sensor have the following relations:

Δ I- α Δ V formula (9)

α in the above equation (9) is a proportionality coefficient.

According to the principle of the photoplethysmography, the area detected by the sensor can be regarded as a fixed lengthL_VThe calculation formula of the intravascular blood volume V is:

V＝L_Vπr²formula (10)

The variation Δ I of the output voltage of the sensor obtained by combining the formula (9) and the formula (10) and neglecting the second order difference term is calculated as follows:

the blood pressure change value Δ P can be obtained from equation (9) and equation (11) by the following calculation:

order:

then there are:

ΔP＝βF

since P is P-P₀If P is equal to Δ P + P₀＝βF+P₀

For the same object to be measured, all parameters in β can be regarded as constants, so that the characteristic value F of blood pressure and the change value delta P of blood pressure can be considered to be in linear relation, and P is₀The basic bias of the blood pressure is shown, the blood pressure can be regarded as a constant value when the same object to be measured is measured in a short time, therefore, the blood pressure value P of the same object to be measured and the blood pressure characteristic value F are in a linear relation in the short time, namely, the established linear blood pressure model has strong theoretical guidance, and the blood pressure value obtained by measuring through the linear blood pressure model is accurate₀The basic bias representing the blood pressure is different, so the corresponding blood pressure linear models are different, and when different basic bias representing the blood pressure is needed, the basic bias representing the blood pressure is differentWhen the individual subject performs continuous blood pressure measurement, linear blood pressure models of different individual subjects need to be established respectively, and then subsequent continuous blood pressure measurement is performed through the linear blood pressure model corresponding to the subject to be measured.

Example 2

The following are embodiments of the apparatus of the present application that may be used to perform embodiments of the method of the present application. For details which are not disclosed in the embodiments of the apparatus of the present application, reference is made to the embodiments of the method of the present application.

Please refer to fig. 8, which illustrates a schematic structural diagram of a continuous blood pressure measuring device based on a volume pulse wave signal according to an embodiment of the present application. The continuous blood pressure measuring device based on the volume pulse wave signal can be realized by software, hardware or a combination of the two to form all or part of the continuous blood pressure measuring device based on the volume pulse wave signal. The continuous blood pressure measuring device 200 based on the volume pulse wave signal includes:

a signal acquisition module 201, configured to acquire a volume pulse wave signal of a subject to be measured; wherein, the volume pulse wave signal at least comprises a pulse wave period;

a blood pressure characteristic value determining module 202, configured to obtain a blood pressure characteristic value according to a cycle value of each pulse wave in the volume pulse wave signal and an amplitude variation value of the pulse wave from a start point of each pulse wave cycle to a preset time;

and the blood pressure value determining module 203 is configured to input the blood pressure feature value into a pre-trained linear blood pressure model of the object to be detected, so as to obtain a blood pressure value of the object to be detected.

According to the embodiment of the application, the blood pressure characteristic value is obtained according to the period value of each pulse wave in the volume pulse wave signal and the amplitude change value of the pulse wave from the starting point of each pulse wave period to the preset time, then the blood pressure characteristic value is input into a linear blood pressure model of a pre-trained object to be measured, the blood pressure value of the object to be measured is obtained, the cuff-type blood pressure measurement method does not need to wait for inflation and deflation of a cuff to measure the blood pressure, the practical application is greatly facilitated, and the continuous measurement of the blood pressure is realized; and the blood pressure characteristic value simultaneously utilizes the amplitude information of the volume pulse wave signal and the wave velocity information represented by the period value, so that the accuracy of blood pressure measurement is improved, the calculation of a linear blood pressure model is simple, and the efficiency of blood pressure measurement is improved.

Referring to fig. 9, in an exemplary embodiment of the present application, a blood pressure linear model training module 204 is further included; the blood pressure linear model training module 204 comprises:

a training sample obtaining module 2041, configured to obtain at least two groups of volume pulse wave signals for training of a subject to be tested, and at least two corresponding groups of blood pressure values for training; wherein the blood pressure value is obtained by a cuff type blood pressure measuring mode; the volume pulse wave signal at least comprises one pulse wave period.

The blood pressure characteristic value training sample determining module 2042 is configured to obtain at least two sets of blood pressure characteristic values according to a period value of each pulse wave in the at least two sets of volume pulse wave signals and an amplitude variation value of the pulse wave from a start point of each pulse wave period to a preset time.

The linear blood pressure model determining module 2043 is configured to calculate and obtain a linear blood pressure model by using at least two sets of the blood pressure feature values as inputs and at least two sets of the corresponding blood pressure values as outputs.

According to the method and the device, at least two groups of blood pressure characteristic values are obtained according to the period value of each pulse wave in at least two groups of volume pulse wave signals and the amplitude change value of the pulse wave from the starting point of each pulse wave period to the preset time, the blood pressure value is obtained in a cuff type blood pressure measuring mode, then the amplitude information and the wave velocity information of the volume pulse wave signals and the accurate blood pressure value are simultaneously utilized to establish a linear blood pressure model, and the accuracy of measuring the blood pressure by the linear blood pressure model is improved.

Since acquiring the volume pulse wave signal is easily affected by the surrounding environment, measuring instruments and the like, in an exemplary embodiment of the present application, the continuous blood pressure measuring device based on the volume pulse wave signal further includes a preprocessing module (not shown in the figure); the preprocessing module is used for: preprocessing the volume pulse wave signal; the pretreatment mode at least comprises one or more of the following modes: mean filtering, baseline drift removal, and high frequency noise removal. The mean filtering may adopt a band-pass filter or a moving average filter. The method for removing the baseline drift and the high-frequency noise can adopt methods such as Gaussian filtering, frequency domain filtering, wavelet transformation and the like for processing. The influence of the surrounding environment, a measuring instrument and the like can be reduced as much as possible by preprocessing the volume pulse wave signal of the object to be measured, and the accuracy of subsequent blood pressure measurement is further improved.

Referring to fig. 10, in an exemplary embodiment of the present application, the blood pressure characteristic value determining module 202 and the blood pressure characteristic value training sample determining module 2042 include a pulse wave period value obtaining module 20210, and the pulse wave period value obtaining module 20210 includes:

a time interval calculating module 20211, configured to obtain a start position and an end position of the pulse wave period, and calculate the number of sampling points between the start position and the end position.

A period value determining module 20212, configured to determine a ratio of the number of sampling points to a sampling rate of the volume pulse wave signal as a period value of the pulse wave.

Referring to fig. 11, in an exemplary embodiment of the present application, the blood pressure characteristic value determining module 202 and the blood pressure characteristic value training sample determining module 2042 include a pulse wave amplitude variation value determining module 20220, and the pulse wave amplitude variation value determining module 20220 includes:

the amplitude determining module 20221 is configured to obtain a pulse wave amplitude corresponding to a start point of a pulse wave period and a pulse wave amplitude corresponding to a preset time; the preset time is a short time period away from the starting point.

The amplitude variation value determining module 20221 is configured to determine a difference between the pulse amplitude corresponding to the preset time and the pulse wave amplitude corresponding to the starting point as the amplitude variation value of the pulse wave.

Referring to fig. 12, in an exemplary embodiment of the present application, the blood pressure characteristic value determining module 202 and the blood pressure characteristic value training sample determining module 2042 include a blood pressure characteristic value calculating module 20230, and the blood pressure characteristic value calculating module 20230 includes:

the first calculating module 20231, configured to calculate a ratio of the n-th power of the pulse amplitude variation value in each pulse wave period to the m-th power of the corresponding pulse wave period value; wherein n and m are positive numbers.

A second calculating module 20232, configured to determine an average value obtained by accumulating and averaging the ratios as a blood pressure feature value.

By obtaining the average value of the ratio of the n-th power of each pulse amplitude variation value to the m-th power of the corresponding pulse wave period value as the blood pressure characteristic value, the detection error caused by the fact that the object to be detected moves within the pulse wave period time or other reasons when a certain pulse wave period is used for analysis alone can be prevented, and therefore the accuracy of the subsequent measurement is influenced.

Example 3

The following are embodiments of the apparatus of the present application that may be used to perform embodiments of the methods of the present application. For details which are not disclosed in the embodiments of the apparatus of the present application, reference is made to the embodiments of the method of the present application.

Referring to fig. 13, the present application further provides an electronic device 300, where the electronic device 300 may be, but is not limited to, various personal computers, notebook computers, smart phones, tablet computers, and the like. The electronic device 300 may include: at least one processor 301, at least one memory 302, at least one network interface 303, a user interface 304, and at least one communication bus 305.

The user interface 304 is mainly used for providing an input interface for a user, acquiring data input by the user, and may include a display terminal and a camera terminal; the display terminal comprises a display screen and a touch screen, and the display screen is used for displaying data processed by the processor, such as blood pressure measurement result data; the touch screen may include: a capacitive screen, an electromagnetic screen, an infrared screen, or the like, and in general, the touch screen may receive a touch operation or a writing operation input by a user through a finger or an input device. Optionally, the user interface 304 may also include a standard wired interface, a wireless interface.

The network interface 303 may optionally include a standard wired interface or a wireless interface (e.g., WI-FI interface).

Wherein the communication bus 305 is used to enable connection communication between these components.

The processor 301 may include one or more processing cores. The processor 301, using various interfaces and lines to connect various parts throughout the electronic device 300, performs various functions of the electronic device 300 and processes data by executing or executing instructions, programs, code sets, or instruction sets stored in the memory 302, and calling data stored in the memory 302. Optionally, the processor 301 may be implemented in at least one hardware form of Digital Signal Processing (DSP), Field-Programmable Gate Array (FPGA), and Programmable Logic Array (PLA). The processor 301 may integrate one or more of a Central Processing Unit (CPU), a Graphics Processing Unit (GPU), a modem, and the like. Wherein, the CPU mainly processes an operating system, a user interface, an application program and the like; the GPU is used for rendering and drawing the content required to be displayed by the display screen; the modem is used to handle wireless communications. It is understood that the modem may not be integrated into the processor 301, but may be implemented by a single chip.

The Memory 302 may include a Random Access Memory (RAM) or a Read-Only Memory (Read-Only Memory). Optionally, the memory 302 includes a non-transitory computer-readable medium. The memory 302 may be used to store instructions, programs, code, sets of codes, or sets of instructions. The memory 302 may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for at least one function (such as a touch function, a sound playing function, an image playing function, etc.), instructions for implementing the above-described method embodiments, and the like; the storage data area may store data and the like referred to in the above respective method embodiments. The memory 302 may alternatively be at least one storage device located remotely from the processor 301. As shown in fig. 13, the memory 302, which is a kind of computer storage medium, may include an operating system, a network communication module, and a user therein.

The processor 301 may be configured to invoke an application program of the data synchronous display method stored in the memory 63, and specifically perform the following operations: acquiring a volume pulse wave signal of an object to be detected; wherein, the volume pulse wave signal at least comprises a pulse wave period; obtaining a blood pressure characteristic value according to the period value of each pulse wave in the volume pulse wave signal and the amplitude change value of the pulse wave from the starting point of each pulse wave period to preset time; and inputting the blood pressure characteristic value into a pre-trained linear blood pressure model of the object to be detected to obtain the blood pressure value of the object to be detected.

In an exemplary embodiment of the present application, the processor 301 further performs the following operations: acquiring at least two groups of volume pulse wave signals for training of a to-be-detected object and at least two corresponding groups of blood pressure values for training; wherein the blood pressure value is obtained by a cuff type blood pressure measuring mode; the volume pulse wave signal at least comprises one pulse wave period; the blood pressure control device is used for obtaining at least two groups of blood pressure characteristic values according to the cycle value of each pulse wave in at least two groups of volume pulse wave signals and the amplitude change value of the pulse wave from the starting point of each pulse wave cycle to preset time; and the linear blood pressure model is obtained by calculation by taking at least two groups of blood pressure characteristic values as input and at least two groups of corresponding blood pressure values as output.

Since acquiring the volume pulse wave signal is susceptible to the surrounding environment and measuring instruments, the processor 301 further performs the following operations in an exemplary embodiment of the present application: preprocessing the volume pulse wave signal; the pretreatment mode at least comprises one or more of the following modes: mean filtering, baseline drift removal, and high frequency noise removal. The mean filtering may adopt a band-pass filter or a moving average filter. The method for removing the baseline drift and the high-frequency noise can adopt methods such as Gaussian filtering, frequency domain filtering, wavelet transformation and the like for processing. The influence of the surrounding environment, a measuring instrument and the like can be reduced as much as possible by preprocessing the volume pulse wave signal of the object to be measured, and the accuracy of subsequent blood pressure measurement is further improved.

In an exemplary embodiment of the present application, the processor 301, when configured to determine the period value of the pulse wave, includes: the pulse wave period calculating device is used for acquiring a starting point position and an end point position of the pulse wave period and calculating the number of sampling points between the starting point position and the end point position; the ratio of the number of the sampling points to the sampling rate of the volume pulse wave signal is determined as the period value of the pulse wave.

In an exemplary embodiment of the present application, the processor 301, when configured to determine the amplitude variation value of the pulse wave, includes: the pulse wave amplitude value acquisition module is used for acquiring a pulse wave amplitude value corresponding to the starting point of a pulse wave period and a pulse wave amplitude value corresponding to preset time; the preset time is a short time deviated from the starting point; and the pulse wave amplitude value determining unit is used for determining the difference value between the pulse amplitude corresponding to the preset time and the pulse wave amplitude value corresponding to the starting point as the pulse wave amplitude value change value.

In an exemplary embodiment of the present application, the processor 301 is configured to perform the determining the blood pressure characteristic value, including performing the following operations: the pulse wave period value calculating device is used for calculating the ratio of the n power of the pulse amplitude variation value in each pulse wave period to the m power of the corresponding pulse wave period value; wherein n and m are positive numbers; and the average value obtained after accumulating and averaging the ratio is determined as the blood pressure characteristic value.

Example 4

The present application further provides a computer-readable storage medium, on which a computer program is stored, where the instructions are suitable for being loaded by a processor and executing the method steps of the foregoing illustrated embodiments, and specific execution processes may refer to specific descriptions shown in embodiment 1, which are not described herein again. The device where the storage medium is located can be an electronic device such as a personal computer, a notebook computer, a smart phone and a tablet computer.

For the apparatus embodiment, since it basically corresponds to the method embodiment, reference may be made to the partial description of the method embodiment for relevant points. The above-described device embodiments are merely illustrative, wherein the components described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the scheme of the application. One of ordinary skill in the art can understand and implement it without inventive effort.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks. These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

In a typical configuration, a computing device includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory.

The memory may include forms of volatile memory in a computer readable medium, Random Access Memory (RAM) and/or non-volatile memory, such as Read Only Memory (ROM) or flash memory (flash RAM). The memory is an example of a computer-readable medium.

Computer-readable media, including both non-transitory and non-transitory, removable and non-removable media, may implement information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), Read Only Memory (ROM), Electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), Digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information that can be accessed by a computing device. As defined herein, a computer readable medium does not include a transitory computer readable medium, such as a modulated data signal and a carrier wave

It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in the process, method, article, or apparatus that comprises the element.

The above are merely examples of the present application and are not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A continuous blood pressure measuring method based on volume pulse wave signals is characterized by comprising the following steps:

2. The continuous blood pressure measuring method based on the volume pulse wave signal as claimed in claim 1, wherein the training process of the linear blood pressure model of the subject comprises the steps of:

acquiring at least two groups of volume pulse wave signals for training of a to-be-detected object and at least two corresponding groups of blood pressure values for training; wherein the blood pressure value is obtained by a cuff type blood pressure measuring mode; the volume pulse wave signal at least comprises one pulse wave period;

obtaining at least two groups of blood pressure characteristic values according to the period value of each pulse wave in at least two groups of volume pulse wave signals and the amplitude change value of the pulse wave from the starting point of each pulse wave period to preset time;

and taking at least two groups of the blood pressure characteristic values as input, taking at least two groups of the corresponding blood pressure values as output, and calculating to obtain a linear blood pressure model.

3. The method for continuous blood pressure measurement based on volume pulse wave signals according to claim 1 or 2, further comprising the step of determining the blood pressure characteristic value, comprising:

calculating the ratio of the n power of the pulse amplitude variation value in each pulse wave period to the m power of the corresponding pulse wave period value; wherein n and m are positive numbers;

and accumulating the ratio values and averaging to obtain an average value, and determining the average value as a blood pressure characteristic value.

4. Method for continuous blood pressure measurement based on volume pulse wave signals according to claim 1 or 2, characterized in that the method further comprises a step of determining the period value of the pulse wave, comprising:

acquiring a starting position and an end position of the pulse wave period, and calculating the number of sampling points between the starting position and the end position;

and determining the ratio of the number of the sampling points to the sampling rate of the volume pulse wave signal as the period value of the pulse wave.

5. The method for continuous blood pressure measurement based on volume pulse wave signals according to claim 1 or 2, further comprising the step of determining the value of the amplitude variation of the pulse wave, comprising:

obtaining a pulse wave amplitude value corresponding to the starting point of a pulse wave period and a pulse wave amplitude value corresponding to preset time; the preset time is a short time deviated from the starting point;

and determining the difference value between the pulse amplitude corresponding to the preset time and the pulse wave amplitude corresponding to the starting point as the amplitude change value of the pulse wave.

6. The method for continuous blood pressure measurement based on volume pulse wave signals according to claim 1 or 2, further comprising: preprocessing the volume pulse wave signal; the pretreatment mode comprises one or more of the following modes: mean filtering, baseline drift removal, and high frequency noise removal.

7. The method for continuous blood pressure measurement based on a volume pulse wave signal according to claim 2, further comprising: and calculating by a least square method to obtain a linear blood pressure model.

8. The continuous blood pressure measuring method based on volume pulse wave signals according to claim 1 or 2, wherein the blood pressure value is a systolic pressure, a diastolic pressure or an average pressure.

9. A continuous blood pressure measuring device based on a volume pulse wave signal, comprising:

10. An electronic device, comprising: a processor and a memory; wherein the memory stores a computer program adapted to be loaded by the processor and to perform the method for continuous blood pressure measurement based on volume pulse wave signals according to any one of claims 1 to 8.

11. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out a method for continuous blood pressure measurement based on volume pulse wave signals according to any one of claims 1 to 8.