Blood pressure estimation device, blood pressure estimation method, and recording medium

Abstract

Provided are a blood pressure estimation device, a blood pressure estimation method, and a recording medium with which it is possible to estimate a highly accurate estimated value of blood pressure. A blood pressure estimation device is provided with: a calculation unit that calculates a calculated value of a first blood pressure and a calculated value of a pulse rate on the basis of biological information; and an estimation unit that estimates an estimated value of a second blood pressure different from the first blood pressure on the basis of the calculated value of the first blood pressure and the calculated value of the pulse rate.

Description

Technical Field

[0001] This disclosure relates to a blood pressure estimation device, a blood pressure estimation method, and a recording medium. Background Technology

[0002] Japanese Patent Application Publication No. 2020-49134 discloses a blood pressure estimation device. In this device, heart rate and corrected normalized pulse wave volume are obtained by photoplethysmography (PPV), and blood pressure is calculated based on the obtained heart rate and PPV. The calculated blood pressure includes systolic blood pressure and diastolic blood pressure (paragraphs 0022, 0030, and 0031). Summary of the Invention

[0003] In the blood pressure estimation device disclosed in Japanese Patent Application Publication No. 2020-49134, there may be a situation where the calculated value of either systolic or diastolic blood pressure is highly accurate, while the calculated value of either systolic or diastolic blood pressure is only low accurate.

[0004] One aspect of this disclosure was made in view of this problem.

[0005] One aspect of this disclosure is intended, for example, to provide a blood pressure estimation device, a blood pressure estimation method, and a recording medium capable of estimating blood pressure estimates with high accuracy.

[0006] Solution for solving the problem The blood pressure estimation device of the first aspect of this disclosure includes: a calculation unit that calculates a first blood pressure value and a pulse rate value based on biological information; and an estimation unit that estimates a second blood pressure value that is different from the first blood pressure value based on the first blood pressure value and the pulse rate value.

[0007] The second method for estimating blood pressure disclosed herein includes: calculating a first blood pressure value and a pulse rate value based on biological information; and estimating a second blood pressure value that is different from the first blood pressure value based on the first blood pressure value and the pulse rate value.

[0008] The third-party computer-readable recording medium disclosed herein records a program that causes a computer to perform the following steps: calculating a first blood pressure value and a pulse rate value based on biological information; and estimating a second blood pressure value that is different from the first blood pressure value based on the first blood pressure value and the pulse rate value.

[0009] The fourth method for estimating blood pressure disclosed herein includes: acquiring multiple sets of measurement values ​​using a blood pressure monitor, each set including a first blood pressure measurement, a pulse rate measurement, and a second blood pressure measurement different from the first blood pressure; creating a function of the first blood pressure and the pulse rate based on the multiple sets of measurement values; calculating the first blood pressure and the pulse rate based on biological information; and estimating the second blood pressure value based on the value of the function when the calculated first blood pressure and the calculated pulse rate are substituted into the function.

[0010] The fifth aspect of the blood pressure estimation device disclosed herein includes: a calculation unit that calculates a first blood pressure value and a period value based on biological information; and an estimation unit that estimates a second blood pressure value that is different from the first blood pressure value based on the first blood pressure value and the period value.

[0011] The sixth method of blood pressure estimation disclosed herein includes: calculating a first blood pressure value and a period value based on biological information; and estimating a second blood pressure value that is different from the first blood pressure value based on the first blood pressure value and the period value.

[0012] The seventh aspect of this disclosure includes a computer-readable recording medium containing a program that causes a computer to perform the following steps: calculating a first blood pressure value and a period value based on biological information; and estimating a second blood pressure value that is different from the first blood pressure value based on the first blood pressure value and the period value.

[0013] The eighth method for estimating blood pressure disclosed herein includes: acquiring multiple sets of measurement values ​​using a blood pressure monitor, each set including a first blood pressure measurement value, a period measurement value, and a second blood pressure measurement value different from the first blood pressure; creating a function of the first blood pressure and the period based on the multiple sets of measurement values; calculating a calculated value of the first blood pressure and a calculated value of the period based on biological information; and estimating an estimated value of the second blood pressure based on the value of the function when the calculated value of the first blood pressure and the calculated value of the period are substituted into the function. Attached Figure Description

[0014] Figure 1 This is a block diagram of the blood pressure estimation device according to the first embodiment.

[0015] Figure 2 This is a block diagram of the computer included in the blood pressure estimation device of the first embodiment.

[0016] Figure 3This is an example of a Bland-Altman plot of the calculated lowest blood pressure value obtained using existing methods.

[0017] Figure 4 This is an example of a Brand-Altmann diagram showing the estimated minimum blood pressure value derived from the blood pressure estimation device of the first embodiment.

[0018] Figure 5 This is a flowchart illustrating the process performed by the blood pressure estimation device of the first embodiment.

[0019] Figure 6 This is a flowchart illustrating the process of creating functions used by the estimation unit included in the blood pressure estimation devices of the first, second, and third embodiments.

[0020] Figure 7 This is a block diagram of the blood pressure estimation device according to the second embodiment.

[0021] Figure 8 This is a flowchart illustrating the process performed by the blood pressure estimation device of the second embodiment.

[0022] Figure 9 This is a block diagram of the blood pressure estimation device according to the third embodiment.

[0023] Figure 10 This is a diagram showing the information processed by the blood pressure estimation device of the third embodiment.

[0024] Figure 11 This is a flowchart illustrating the process performed by the blood pressure estimation device of the third embodiment. Detailed Implementation

[0025] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In the drawings, the same or equivalent elements are labeled with the same reference numerals, and repeated descriptions are omitted.

[0026] 1 First Implementation Method 1.1 Blood Pressure Estimation Device Figure 1 This is a block diagram of the blood pressure estimation device according to the first embodiment.

[0027] like Figure 1As shown, the blood pressure estimation device 1 of the first embodiment acquires the pulse wave 101 of a living organism, calculates the highest blood pressure value 102 and the pulse rate value 104 from the acquired pulse wave 101, and estimates the lowest blood pressure value 106 based on the calculated highest blood pressure value 102 and the calculated pulse rate value 104. The highest blood pressure is the blood pressure when the heart contracts most strongly, also known as systolic blood pressure, maximum blood pressure, etc. The lowest blood pressure is the blood pressure when the heart expands most fully, also known as diastolic blood pressure, minimum blood pressure, etc. In the blood pressure estimation device 1, the highest blood pressure is a first blood pressure for which a highly accurate calculation value can be obtained, and the lowest blood pressure is a second blood pressure that differs from the first blood pressure and for which a highly accurate calculation value cannot be obtained.

[0028] like Figure 1 As shown, the blood pressure estimation device 1 includes an acquisition unit 11, a calculation unit 12, and an estimation unit 13.

[0029] The acquisition unit 11 acquires the pulse wave 101 of the organism and transmits the acquired pulse wave 101 to the calculation unit 12. Alternatively, the pulse wave 101 acquired by a device other than the blood pressure estimation device 1 can be input to the blood pressure estimation device 1 and the input pulse wave 101 can be transmitted to the calculation unit 12.

[0030] The acquisition unit 11 includes a pulse wave sensor. The pulse wave sensor can be a contact pulse wave sensor or a non-contact pulse wave sensor. A contact pulse wave sensor acquires the pulse wave 101 of a living organism while in contact with it. Contact pulse wave sensors include reflective photoelectric pulse wave sensors, transmissive photoelectric pulse wave sensors, piezoelectric sensors, etc. A non-contact pulse wave sensor acquires the pulse wave 101 of a living organism without contact with it. Non-contact pulse wave sensors include pulse wave sensors incorporating microwave Doppler sensors, sensors that acquire pulse waves from images of a living organism using photoplethysmography, etc.

[0031] The calculation unit 12 calculates the maximum blood pressure value 102 and the pulse rate value 104 from the transmitted pulse wave 101, and transmits these values ​​to the estimation unit 13. For example, the calculation unit 12 calculates the maximum blood pressure value 102 based on information such as the amplitude, wavelength, waveform characteristics, and spectrum of the pulse wave 101, and calculates the pulse rate value 104 based on information such as the period, spectrum, spectrogram, and number of peaks of the pulse wave 101. For example, the pulse rate value 104 can be calculated by taking the reciprocal of the period of the pulse wave 101.

[0032] The calculation unit 12 can calculate the highest blood pressure value 102 with high accuracy, but it cannot calculate the lowest blood pressure value with high accuracy. Furthermore, the calculation unit 12 can calculate the pulse rate value 104 with high accuracy.

[0033] The acquisition unit 11 can also acquire biological information other than the pulse wave 101, and the calculation unit 12 can also calculate the calculated value 102 of the highest blood pressure and the calculated value 104 of the pulse rate based on the acquired biological information other than the pulse wave 101. The biological information other than the pulse wave 101 includes time changes in the image of the biological body and time changes in the facial color of the biological body.

[0034] The estimation unit 13 estimates the estimated value 106 of the lowest blood pressure based on the received calculated value 102 of the highest blood pressure and the calculated value 104 of the pulse rate, and outputs the estimated value 106 of the lowest blood pressure. The estimation unit 13 uses a pre-prepared estimation formula for estimating the estimated value 106 of the lowest blood pressure based on the calculated value 102 of the highest blood pressure and the calculated value 104 of the pulse rate. The estimation formula used is a function 111 of the highest blood pressure and the pulse rate. The estimation unit 13 estimates the estimated value 106 of the lowest blood pressure based on the value of function 111 when the calculated value 102 of the highest blood pressure and the calculated value 104 of the pulse rate are substituted into function 111. For example, the estimation unit 13 can directly use the value of function 111 when the calculated value 102 of the highest blood pressure and the calculated value 104 of the pulse rate are substituted into function 111 as the estimated value 106 of the lowest blood pressure.

[0035] Generally speaking, the calculated pulse rate value 104 has high accuracy. Therefore, when the calculation unit 12 can calculate the calculated value 102 of the highest blood pressure with high accuracy, and the function 111 can accurately represent the relationship between the highest blood pressure, pulse rate, and lowest blood pressure, even if the calculation unit 12 cannot calculate the calculated value of the lowest blood pressure with high accuracy, the estimation unit 13 can estimate the estimated value 106 of the lowest blood pressure with high accuracy based on the calculated value 102 of the highest blood pressure, the calculated value 104 of the pulse rate, and the function 111.

[0036] The blood pressure estimation device 1 may also include a display unit that displays the estimated value 106 of the lowest blood pressure, a communication unit that transmits the estimated value 106 of the lowest blood pressure to the outside, and a storage unit that stores the estimated value 106 of the lowest blood pressure.

[0037] 1.2 Functions used to estimate the lowest estimated blood pressure value Function 111 preferably includes the factor SYS when the highest blood pressure is set as SYS and the pulse rate is set as HR. γ_1 ×HR γ_2 Factor SYS γ_1 ×HR γ_2The coefficients γ_1 and γ_2 included in the function can be determined by performing a multiple regression analysis using multiple sets of measurements obtained from a blood pressure monitor. Each set of measurements includes the highest blood pressure, the pulse rate, and the lowest blood pressure. The blood pressure monitor only needs to be able to obtain highly accurate measurements of the highest blood pressure, pulse rate, and lowest blood pressure; for example, a typical upper arm cuff blood pressure monitor is sufficient. Function 111 includes the factor SYS. γ_1 ×HR γ_2 When the coefficients γ_1 and γ_2 are determined by performing a multivariate regression analysis, function 111 can accurately represent the relationship between the highest blood pressure, pulse rate, and lowest blood pressure.

[0038] Function 111 is more preferably represented by mathematical formula (1) when the highest blood pressure is set as SYS, the pulse rate as HR, and the lowest blood pressure as DIA. The coefficients α_0, α_1, α_2, α_3, α_4, γ_1, and γ_2 included in mathematical formula (1) can be determined by performing a multiple regression analysis using multiple sets of measurement values ​​obtained from a blood pressure monitor, each set of measurement values ​​including the highest blood pressure measurement, the pulse rate measurement, and the lowest blood pressure measurement. The blood pressure monitor only needs to be able to obtain the highest blood pressure measurement, the pulse rate measurement, and the lowest blood pressure measurement with high accuracy, such as a general upper arm cuff blood pressure monitor.

[0039] [Mathematical Expression 1] DIA = α_0 + (α_1 + α_2 × SYS) γ_1 (α_3+α_4×HR) γ_2 (1) The estimation unit 13 can also use the calculated value of the period instead of the calculated value of the pulse rate 104 to estimate the estimated value of the lowest blood pressure 106. In other words, the calculation unit 12 can calculate the period of the pulse wave 101, and the estimation unit 13 can estimate the estimated value of the lowest blood pressure 106 based on the transmitted calculated value of the highest blood pressure 102 and the calculated value of the period. The calculation unit 12 is capable of calculating the period with high accuracy. The function 111 preferably includes the factor SYS when the highest blood pressure is set to SYS and the period is set to T. γ_1 ×T γ_2 More preferably, when the highest blood pressure is set as SYS, the period is set as T, and the lowest blood pressure is set as DIA, the mathematical formula DIA = α_0 + (α_1 + α_2 × SYS) is used. γ_1 (α_3+α_4×T) γ_2 The period can be calculated by taking the reciprocal of the calculated pulse count of 104. Furthermore, since the period is the time between the peak values ​​of the pulse wave 101, it can also be calculated for each individual pulse.

[0040] 1.3 Estimation of blood pressure values ​​other than the lowest blood pressure Presumption section 13 can also estimate blood pressure values ​​other than the minimum blood pressure. Blood pressure other than the minimum blood pressure includes pulse pressure, mean blood pressure, etc. Pulse pressure is the blood pressure obtained by subtracting the minimum blood pressure from the maximum blood pressure. Mean blood pressure is the blood pressure obtained by adding one-third of the pulse pressure to the minimum blood pressure.

[0041] In the case of estimating the estimated pulse pressure, the estimation unit 13, similarly to the case of estimating the estimated minimum blood pressure 106, estimates the pulse pressure based on the value of a function obtained by substituting the calculated values ​​102 (maximum blood pressure) and 104 (pulse rate) into a function of maximum blood pressure and pulse rate. Preferably, the function includes the factor SYS when the maximum blood pressure is set to SYS and the pulse rate to HR. γ_1 ×HR γ_2 More preferably, when the highest blood pressure is set as SYS, the pulse rate as HR, and the pulse pressure as PP, it is represented by mathematical formula (2). Factor SYS γ_1 ×HR γ_2 The coefficients γ_1 and γ_2 contained in the formula, as well as the coefficients α_0, α_1, α_2, α_3, α_4, γ_1, and γ_2 contained in the mathematical formula (2), can be determined by performing a multiple regression analysis using multiple sets of measurement values ​​obtained from a sphygmomanometer. Each set of measurement values ​​includes the measurement of the highest blood pressure, the measurement of the pulse rate, and the measurement of the pulse pressure. A sphygmomanometer that can obtain high-precision measurements of the highest blood pressure, the measurement of the pulse rate, and the measurement of the pulse pressure is sufficient, such as a general upper arm cuff sphygmomanometer.

[0042] [Mathematical Expression 2] PP = α_0 + (α_1 + α_2 × SYS) γ_1 (α_3+α_4×HR) γ_2 (2) Furthermore, when estimating the estimated pulse pressure, the estimation unit 13, similarly to the case of estimating the estimated minimum blood pressure 106, can also estimate the estimated pulse pressure based on the function value obtained by substituting the calculated value of the maximum blood pressure 102 and the calculated value of the period into the function of the maximum blood pressure and the period. Preferably, the function of the period includes the factor SYS when the maximum blood pressure is set to SYS and the period is set to T. γ_1 ×T γ_2 More preferably, when the highest blood pressure is set as SYS, the period is set as T, and the pulse pressure is set as PP, the mathematical formula PP = α_0 + (α_1 + α_2 × SYS) is used. γ_1 (α_3+α_4×T) γ_2 )express.

[0043] In the case of estimating the estimated value of the mean blood pressure, similarly to the case of estimating the estimated value of the minimum blood pressure 106, the estimation unit 13 estimates the estimated value of the mean blood pressure based on the value of the function obtained by substituting the calculated value of the maximum blood pressure 102 and the calculated value of the pulse rate 104 into the function of the maximum blood pressure and pulse rate. Preferably, the function includes the factor SYS when the maximum blood pressure is set to SYS and the pulse rate is set to HR. γ_1 ×HR γ_2 More preferably, when the highest blood pressure is set as SYS, the pulse rate as HR, and the mean blood pressure as MAP, it is represented by mathematical formula (3). Factor SYS γ_1 ×HR γ_2 The coefficients γ_1 and γ_2 contained in the formula, as well as the coefficients α_0, α_1, α_2, α_3, α_4, γ_1, and γ_2 contained in the mathematical formula (3), can be determined by performing a multiple regression analysis on multiple sets of measurement values ​​obtained using a sphygmomanometer. Each set of measurement values ​​includes the highest blood pressure measurement, the pulse rate measurement, and the average blood pressure measurement. A sphygmomanometer that can obtain highly accurate measurements of the highest blood pressure, the pulse rate, and the average blood pressure is sufficient; for example, a typical upper arm cuff sphygmomanometer is suitable.

[0044] [Mathematical Expression 3] MAP = α_0 + (α_1 + α_2 × SYS) γ_1 (α_3+α_4×HR) γ_2 (3) Furthermore, in the case of estimating the estimated value of the mean blood pressure, similarly to the case of estimating the estimated value of the minimum blood pressure 106, the estimation unit 13 can also estimate the estimated value of the mean blood pressure based on the value of the function obtained by substituting the calculated value of the maximum blood pressure 102 and the calculated value of the period into the function of the maximum blood pressure and the period. Preferably, the function of the period includes the factor SYS when the maximum blood pressure is set to SYS and the period is set to T. γ_1 ×T γ_2 More preferably, when the highest blood pressure is set as SYS, the period is set as T, and the average blood pressure is set as MAP, the mathematical formula MAP = α_0 + (α_1 + α_2 × SYS) is used. γ_1 (α_3+α_4×T) γ_2 )express.

[0045] 1.4 Execution of the computer-based blood pressure estimation program Figure 2 This is a block diagram of the computer included in the blood pressure estimation device of the first embodiment.

[0046] like Figure 2As shown, the blood pressure estimation device 1 includes a computer 21. The computer 21 includes a processor 31, a memory 32, and a storage device 33. The blood pressure estimation program 41 is installed in the storage device 33.

[0047] The processor 31 is, for example, a central processing unit (CPU) or a graphics processing unit (GPU). The memory 32 is, for example, random access memory (RAM) or read-only memory (ROM). The storage device 33 is, for example, a solid-state drive (SSD) or a hard disk drive (HDD). The processor 31 executes the blood pressure estimation program 41 loaded from the storage device 33 into the memory 32, and causes the computer 21 to operate as an element of the blood pressure estimation device 1. For example, the processor 31 executes the blood pressure estimation program 41, causing the computer 21 to operate as a calculation unit 12 and a estimation unit 13. The memory 32 and the storage device 33 are non-temporary storage media for storing the blood pressure estimation program 41.

[0048] 1.5 Comparison between the accuracy of the calculated minimum blood pressure value obtained by existing methods and the accuracy of the minimum blood pressure estimated by the blood pressure estimation device of the first embodiment. Figure 3 This is an example of a Brand-Altmann diagram of the calculated lowest blood pressure value obtained using existing methods. Figure 4 This is an example of a Brand-Altmann diagram showing the estimated minimum blood pressure value derived from the blood pressure estimation device of the first embodiment.

[0049] exist Figure 3 In the example of the Brand-Altmann diagram, the horizontal axis represents the calculated minimum blood pressure value and the average of the minimum blood pressure values ​​obtained from the blood pressure monitor, while the vertical axis represents the difference between the calculated minimum blood pressure value and the measured minimum blood pressure value obtained from the blood pressure monitor. Figure 4 In the example of the Brand-Altmann diagram, the horizontal axis represents the estimated minimum blood pressure and the average of the minimum blood pressure obtained from the blood pressure monitor, and the vertical axis represents the difference between the estimated minimum blood pressure and the measured minimum blood pressure obtained from the blood pressure monitor.

[0050] exist Figure 3 The Brand-Altmann plot is an example where the error range, expressed as ±1.96 × standard deviation (SD), is 47.5. In contrast, in... Figure 4 In the example of the Brand-Altmann diagram, the error range, expressed as ±1.96 × standard deviation (SD), is 25.4. This means that the estimated minimum blood pressure value derived by the blood pressure estimation device 1 is more accurate than the calculated minimum blood pressure value derived by existing methods.

[0051] 1.6 Processing flow of the blood pressure estimation device Figure 5 This is a flowchart illustrating the process performed by the blood pressure estimation device of the first embodiment.

[0052] Blood pressure estimation device 1 is activated Figure 5 Steps S101 to S103 are shown.

[0053] In step S101, the acquisition unit 11 acquires the pulse wave 101.

[0054] In the next step S102, the calculation unit 12 calculates the highest blood pressure value 102 and the pulse rate value 104 based on the acquired pulse wave 101.

[0055] In the next step S103, the estimation unit 13 estimates the estimated value 106 of the lowest blood pressure based on the calculated value 102 of the highest blood pressure and the calculated value 104 of the pulse rate.

[0056] 1.7 Processing of creating functions used by the presumption section Figure 6 This is a flowchart illustrating the process of creating a function used by the estimation unit included in the blood pressure estimation device of the first embodiment.

[0057] When function 111 is created, execution Figure 6 Steps S111 and S112 are shown.

[0058] In step S111, multiple sets of measurement values ​​are acquired using a blood pressure monitor. Each set of measurement values ​​includes the highest blood pressure measurement, the pulse rate measurement, and the lowest blood pressure measurement. The blood pressure monitor only needs to be able to acquire highly accurate measurements of the highest blood pressure, pulse rate, and lowest blood pressure; for example, a typical upper arm cuff blood pressure monitor is suitable.

[0059] In the next step S112, a function 111 is created based on the acquired sets of measurements. At this point, the coefficients included in function 111 are determined by performing a multiple regression analysis using the sets of measurements.

[0060] Second Implementation Method The differences between the second embodiment and the first embodiment will be explained below. For parts not described herein, the second embodiment employs the same configuration as the first embodiment.

[0061] Figure 7 This is a block diagram of the blood pressure estimation device according to the second embodiment.

[0062] like Figure 7As shown, the blood pressure estimation device 2 of the second embodiment acquires the pulse wave 101 of a living organism, calculates the calculated value 103 of the lowest blood pressure and the calculated value 104 of the pulse rate based on the acquired pulse wave 101, and estimates the estimated value 105 of the highest blood pressure based on the calculated value 103 of the lowest blood pressure and the calculated value 104 of the pulse rate. In the blood pressure estimation device 2, the lowest blood pressure is a first blood pressure for which a highly accurate calculated value can be obtained, and the highest blood pressure is a second blood pressure that is different from the first blood pressure and for which a highly accurate calculated value cannot be obtained.

[0063] The calculation unit 12 calculates the minimum blood pressure value 103 and the pulse rate value 104 based on the transmitted pulse wave 101, and transmits these values ​​to the estimation unit 13. For example, the calculation unit 12 calculates the minimum blood pressure value 103 based on information such as the amplitude, wavelength, waveform characteristics, and spectrum of the pulse wave 101, and calculates the pulse rate value 104 based on information such as the period, spectrum, spectrogram, and number of peaks of the pulse wave 101. For instance, the pulse rate value 104 can be calculated by taking the reciprocal of the period of the pulse wave 101.

[0064] The calculation unit 12 can calculate the lowest blood pressure value 103 with high accuracy, but it cannot calculate the highest blood pressure value with high accuracy. Furthermore, the calculation unit 12 can calculate the pulse rate value 104 with high accuracy.

[0065] The estimation unit 13 estimates the estimated maximum blood pressure value 105 based on the received calculated minimum blood pressure value 103 and pulse rate value 104, and outputs the estimated maximum blood pressure value 105. The estimation unit 13 uses a pre-prepared estimation formula for estimating the estimated maximum blood pressure value 105 based on the calculated minimum blood pressure value 103 and pulse rate value 104. The estimation formula used is a function 112 of minimum blood pressure and pulse rate. The estimation unit 13 estimates the estimated maximum blood pressure value 105 based on the function value when the calculated minimum blood pressure value 103 and pulse rate value 104 are substituted into the function 112. For example, the estimation unit 13 can directly use the function value when the calculated minimum blood pressure value 103 and pulse rate value 104 are substituted into the function 112 as the estimated maximum blood pressure value 105.

[0066] Generally speaking, the calculated pulse rate value 104 has high accuracy. Therefore, when the calculation unit 12 can calculate the calculated value 103 of the lowest blood pressure with high accuracy, and the function 112 can express the relationship between the lowest blood pressure, pulse rate, and highest blood pressure with high accuracy, even if the calculation unit 12 cannot calculate the calculated value of the highest blood pressure with high accuracy, the estimation unit 13 can estimate the estimated value 105 of the highest blood pressure with high accuracy based on the calculated value 103 of the lowest blood pressure, the calculated value 104 of the pulse rate, and the function 112.

[0067] Function 112 preferably includes the factor DIA when the lowest blood pressure is set to DIA and the pulse rate is set to HR. γ_1 ×HR γ_2 Factor DIA γ_1 ×HR γ_2 The coefficients γ_1 and γ_2 included in the function can be determined by performing a multiple regression analysis using multiple sets of measurements obtained from a blood pressure monitor. Each set of measurements includes the lowest blood pressure, pulse rate, and highest blood pressure. The blood pressure monitor only needs to be able to obtain highly accurate measurements of the lowest blood pressure, pulse rate, and highest blood pressure; for example, a typical upper arm cuff blood pressure monitor is sufficient. The function 112 includes the factor DIA. γ_1 ×HR γ_2 Furthermore, given that the coefficients γ_1 and γ_2 are determined through multiple regression analysis, function 112 can accurately represent the relationship between minimum blood pressure, pulse rate, and maximum blood pressure.

[0068] Function 112 is more preferably represented by mathematical formula (4) when the lowest blood pressure is set to DIA, the pulse rate to HR, and the highest blood pressure to SYS. The coefficients α_0, α_1, α_2, α_3, α_4, γ_1, and γ_2 contained in mathematical formula (4) can be determined by performing a multiple regression analysis using multiple sets of measurement values ​​obtained from the blood pressure monitor, each set of measurement values ​​including the lowest blood pressure measurement, the pulse rate measurement, and the highest blood pressure measurement. The blood pressure monitor only needs to be able to obtain the lowest blood pressure measurement, the pulse rate measurement, and the highest blood pressure measurement with high accuracy, such as a general upper arm cuff blood pressure monitor.

[0069] [Mathematical Expression 4] SYS = α_0 + (α_1 + α_2 × DIA) γ_1 (α_3+α_4×HR) γ_2 (4) Alternatively, the estimation unit 13 can use the calculated value of the period instead of the calculated value of the pulse rate 104 to estimate the estimated value of the highest blood pressure 105. In other words, the calculation unit 12 can calculate the period of the pulse wave 101, and the estimation unit 13 can estimate the estimated value of the highest blood pressure 105 based on the transmitted calculated value of the lowest blood pressure 103 and the calculated value of the period. The calculation unit 12 is capable of calculating the period with high accuracy. The function 112 preferably includes the factor SYS when the lowest blood pressure is set to DIA and the period is set to T. γ_1 ×T γ_2 More preferably, when the lowest blood pressure is set as DIA, the period is set as T, and the highest blood pressure is set as SYS, the mathematical formula SYS=α_0+(α_1+α_2×DIA) is used. γ_1 (α_3+α_4×T) γ_2 )express.

[0070] Figure 8 This is a flowchart illustrating the process performed by the blood pressure estimation device of the second embodiment.

[0071] Blood pressure estimation device 2 execution Figure 8 The steps S201 to S203 are shown.

[0072] In step S201, the acquisition unit 11 acquires the pulse wave 101.

[0073] In the next step S202, the calculation unit 12 calculates the minimum blood pressure value 103 and the pulse rate value 104 based on the acquired pulse wave 101.

[0074] In the next step S203, the estimation unit 13 estimates the estimated value 105 of the highest blood pressure based on the calculated value 103 of the lowest blood pressure and the calculated value 104 of the pulse rate.

[0075] Figure 6 It is also a flowchart illustrating the process of creating the function used by the estimation unit included in the blood pressure estimation device of the second embodiment.

[0076] When function 112 is created, execution Figure 6 Steps S111 and S112 are shown.

[0077] In step S111, multiple sets of measurement values ​​are acquired using a blood pressure monitor. Each set of measurement values ​​includes the lowest blood pressure measurement, the pulse rate measurement, and the highest blood pressure measurement. The blood pressure monitor only needs to be able to acquire the lowest blood pressure measurement, pulse rate measurement, and highest blood pressure measurement with high accuracy; for example, a typical upper arm cuff blood pressure monitor is suitable.

[0078] In the next step S112, function 112 is created based on the obtained set of measurements. At this point, the coefficients included in function 112 are determined by performing a multiple regression analysis using the set of measurements.

[0079] 3 Third Implementation Method The differences between the third embodiment and the first embodiment will be explained below. For any parts not described, the third embodiment also employs the same configuration as the first embodiment.

[0080] Figure 9 This is a block diagram of the blood pressure estimation device according to the third embodiment. Figure 10 This is a diagram showing the information processed by the blood pressure estimation device of the third embodiment.

[0081] like Figure 9 and Figure 10 As shown, Figure 9 The blood pressure estimation device 3 of the third embodiment shown acquires the pulse wave 101 of a living organism, calculates the highest blood pressure value 102, the lowest blood pressure value 103, and the pulse rate value 104 based on the acquired pulse wave 101, and estimates the lowest blood pressure value 106 based on the calculated highest blood pressure value 102 and the calculated pulse rate value 104. It then estimates the highest blood pressure value 105 based on the calculated lowest blood pressure value 103 and the calculated pulse rate value 104, obtains a corrected highest blood pressure value 107 based on the calculated highest blood pressure value 102 and the estimated highest blood pressure value 105, and obtains a corrected lowest blood pressure value 108 based on the calculated lowest blood pressure value 103 and the estimated lowest blood pressure value 106. In the blood pressure estimation device 3, one of the highest and lowest blood pressure is a first blood pressure, and the other is a second blood pressure, which is different from the first blood pressure. Alternatively, the blood pressure estimation device 3 of the third embodiment can also acquire the pulse wave 101 of the organism, calculate the highest blood pressure value 102, the lowest blood pressure value 103 and the period of the pulse wave 101 based on the acquired pulse wave 101, estimate the lowest blood pressure value 106 based on the calculated highest blood pressure value 102 and the calculated period, estimate the highest blood pressure value 105 based on the calculated lowest blood pressure value 103 and the calculated period, obtain the corrected value 107 of the highest blood pressure based on the calculated highest blood pressure value 102 and the estimated highest blood pressure value 105, and obtain the corrected value 108 of the lowest blood pressure based on the calculated lowest blood pressure value 103 and the estimated lowest blood pressure value 106.

[0082] like Figure 9 As shown, the blood pressure estimation device 3 includes an acquisition unit 11, a calculation unit 12, an estimation unit 13, and a correction unit 14.

[0083] The calculation unit 12 calculates the highest blood pressure value 102, the lowest blood pressure value 103, and the pulse rate value 104 based on the pulse wave 101. It then transmits these values ​​to the estimation unit 13 and to the correction unit 14. For example, the calculation unit 12 calculates the highest blood pressure value 102 and the lowest blood pressure value 103 based on information such as the amplitude, wavelength, waveform characteristics, and spectrum of the pulse wave 101. It also calculates the pulse rate value 104 based on information such as the period, spectrum, spectrogram, and number of peaks of the pulse wave 101. For instance, the pulse rate value 104 can be calculated by taking the reciprocal of the period of the pulse wave 101.

[0084] The estimation unit 13 estimates the estimated value 106 of the lowest blood pressure based on the transmitted calculated value 102 of the highest blood pressure and the calculated value 104 of the pulse rate. It also estimates the estimated value 105 of the highest blood pressure based on the transmitted calculated value 103 of the lowest blood pressure and the calculated value 104 of the pulse rate. The estimated values ​​106 of the lowest blood pressure and 105 of the highest blood pressure are then transmitted to the correction unit 14. The estimation unit 13 uses a pre-prepared first estimation formula for estimating the estimated value 106 of the lowest blood pressure based on the calculated value 102 of the highest blood pressure and the calculated value 104 of the pulse rate, and a second estimation formula for estimating the estimated value 105 of the highest blood pressure based on the calculated value 103 of the lowest blood pressure and the calculated value 104 of the pulse rate. The first estimation formula used is a function 111 of the highest blood pressure and the pulse rate, and the second estimation formula used is a function 112 of the lowest blood pressure and the pulse rate. The estimation unit 13 estimates the estimated value of the lowest blood pressure 106 based on the function value obtained by substituting the calculated value of the highest blood pressure 102 and the calculated value of the pulse rate 104 into the function 111; and estimates the estimated value of the highest blood pressure 105 based on the function value obtained by substituting the calculated value of the lowest blood pressure 103 and the calculated value of the pulse rate 104 into the function 112. For example, the estimation unit 13 can directly use the function value obtained by substituting the calculated value of the highest blood pressure 102 and the calculated value of the pulse rate 104 into the function 111 as the estimated value of the lowest blood pressure 106, and directly use the function value obtained by substituting the calculated value of the lowest blood pressure 103 and the calculated value of the pulse rate 104 into the function 112 as the estimated value of the highest blood pressure 105. Alternatively, the estimation unit 13 may use the calculated value of the pulse wave 101 cycle instead of the calculated value of the pulse number 104 to estimate the estimated value of the lowest blood pressure 106, and estimate the estimated value of the highest blood pressure 105 based on the calculated value of the pulse wave 101 cycle, and then transmit the estimated value of the lowest blood pressure 106 and the estimated value of the highest blood pressure 105 to the correction unit 14.

[0085] The correction unit 14 obtains the corrected value 107 of the highest blood pressure based on the calculated value 102 and the estimated value 105 of the highest blood pressure, and obtains the corrected value 108 of the lowest blood pressure based on the calculated value 103 and the estimated value 106 of the lowest blood pressure, and outputs the obtained corrected values ​​107 and 108 of the highest and lowest blood pressure. The correction unit 14 uses the arithmetic mean of the calculated value 102 and the estimated value 105 of the highest blood pressure as the corrected value 107 of the highest blood pressure, and the arithmetic mean of the calculated value 103 and the estimated value 106 of the lowest blood pressure as the corrected value 108 of the lowest blood pressure. The correction unit 14 may also use average values ​​other than the arithmetic mean as the corrected value 107 of the highest blood pressure and the corrected value 108 of the lowest blood pressure. For example, the correction unit 14 can use the weighted average of the calculated value 102 of the highest blood pressure and the estimated value 105 of the highest blood pressure as the corrected value 107 of the highest blood pressure, and it can also use the weighted average of the calculated value 103 of the lowest blood pressure and the estimated value 106 of the lowest blood pressure as the corrected value 108 of the lowest blood pressure. In the weighted average of the calculated value 102 of the highest blood pressure and the estimated value 105 of the highest blood pressure, the weights of the calculated value 102 of the highest blood pressure and the estimated value 105 of the highest blood pressure are different from each other. Similarly, in the weighted average of the calculated value 103 of the lowest blood pressure and the estimated value 106 of the lowest blood pressure, the weights of the calculated value 103 of the lowest blood pressure and the estimated value 106 of the lowest blood pressure are different from each other.

[0086] With high accuracy in the calculated value 102 for the highest blood pressure, the estimated value 106 for the lowest blood pressure also has high accuracy.

[0087] Given that the estimated minimum blood pressure value 106 has high accuracy, and the calculated minimum blood pressure value 103 also has high accuracy, both the calculated minimum blood pressure value 103 and the estimated minimum blood pressure value 106, which form the basis for the corrected minimum blood pressure value 108, have high accuracy and are close to each other. Therefore, the corrected minimum blood pressure value 108 has high accuracy.

[0088] If the estimated minimum blood pressure value 106 has high accuracy, and the calculated minimum blood pressure value 103 has only low accuracy, the calculated minimum blood pressure value 103 with only low accuracy is corrected by the estimated minimum blood pressure value 106 with high accuracy to obtain the corrected minimum blood pressure value 108. Therefore, the corrected minimum blood pressure value 108 has higher accuracy than the calculated minimum blood pressure value 103.

[0089] With high accuracy in the calculated value of the lowest blood pressure 103, the estimated value of the highest blood pressure 105 also has high accuracy.

[0090] Given that the estimated maximum blood pressure value 105 has high accuracy, and the calculated maximum blood pressure value 102 also has high accuracy, both the calculated maximum blood pressure value 102 and the estimated maximum blood pressure value 105, which form the basis for the corrected maximum blood pressure value 107, have high accuracy and are close to each other. Therefore, the corrected maximum blood pressure value 107 has high accuracy.

[0091] When the estimated maximum blood pressure value 105 has high precision and the calculated maximum blood pressure value 102 has only low precision, the calculated maximum blood pressure value 102 with only low precision will be corrected by the estimated maximum blood pressure value 105 with high precision, thereby obtaining the corrected maximum blood pressure value 107. Therefore, the corrected maximum blood pressure value 107 has higher precision than the calculated maximum blood pressure value 102.

[0092] Therefore, the corrected value 108 for the lowest blood pressure and the corrected value 107 for the highest blood pressure have higher accuracy than the calculated value 103 for the lowest blood pressure and the calculated value 102 for the highest blood pressure, respectively. That is, the correction unit 14 helps to improve accuracy.

[0093] Figure 11 This is a flowchart illustrating the process performed by the blood pressure estimation device of the third embodiment.

[0094] Blood pressure estimation device 3 execution Figure 11 Steps S301 to S304 are shown.

[0095] In step S301, the acquisition unit 11 acquires the pulse wave 101.

[0096] In the next step S302, the calculation unit 12 calculates the highest blood pressure value 102, the lowest blood pressure value 103, and the pulse rate value 104 based on the acquired pulse wave 101.

[0097] In the next step S303, the estimation unit 13 estimates the estimated value of the lowest blood pressure 106 based on the calculated value of the highest blood pressure 102 and the calculated value of the pulse rate 104; and estimates the estimated value of the highest blood pressure 105 based on the calculated value of the lowest blood pressure 103 and the calculated value of the pulse rate 104.

[0098] In the next step S304, the correction unit 14 obtains the corrected value 107 of the highest blood pressure based on the calculated value 102 of the highest blood pressure and the estimated value 105 of the highest blood pressure, and obtains the corrected value 108 of the lowest blood pressure based on the calculated value 103 of the lowest blood pressure and the estimated value 106 of the lowest blood pressure.

[0099] Figure 6It is also a flowchart illustrating the process of creating the function used by the estimation unit included in the blood pressure estimation device of the third embodiment.

[0100] With functions 111 and 112 created, execution Figure 6 Steps S111 and S112 are shown.

[0101] In step S111, multiple sets of measurement values ​​are acquired using a blood pressure monitor. Each set of measurement values ​​includes the highest blood pressure measurement, the pulse rate measurement, and the lowest blood pressure measurement. The blood pressure monitor only needs to be able to acquire highly accurate measurements of the highest blood pressure, pulse rate, and lowest blood pressure; for example, a typical upper arm cuff blood pressure monitor is suitable.

[0102] In the next step S112, functions 111 and 112 are created based on the obtained set of measurements. At this point, multiple regression analysis is performed using the set of measurements to determine the coefficients included in functions 111 and 112.

[0103] This disclosure is not limited to the above-described embodiments, and may be replaced by a configuration that is substantially the same as the configuration shown in the above-described embodiments, a configuration that has the same effect, or a configuration that can achieve the same purpose.

Claims

1. A blood pressure estimation device, characterized by, comprises: a calculating section that calculates a calculated value of a first blood pressure and a calculated value of a pulse rate from biological information; and an estimating section that estimates an estimated value of a second blood pressure different from the first blood pressure, based on the calculated value of the first blood pressure and the calculated value of the pulse rate.

2. The blood pressure estimating apparatus according to claim 1, wherein the estimating section estimates the estimated value of the second blood pressure based on a value of a function of the first blood pressure and the pulse rate when the calculated value of the first blood pressure and the calculated value of the pulse rate are substituted into the function.

3. A blood pressure estimation device, characterized by, comprises: a calculating section that calculates a calculated value of a first blood pressure and a calculated value of a period from biological information; an estimating section that estimates an estimated value of a second blood pressure different from the first blood pressure, based on the calculated value of the first blood pressure and the calculated value of the period.

4. The blood pressure estimating apparatus according to claim 3, wherein the estimating section estimates the estimated value of the second blood pressure based on a function value of a function of the first blood pressure and the period after the calculated value of the first blood pressure and the calculated value of the period are substituted into the function.

5. The blood pressure estimating apparatus according to any one of claims 1 to 4, wherein the first blood pressure is a maximum blood pressure, the second blood pressure is a minimum blood pressure.

6. The blood pressure estimating apparatus according to claim 1 or 2, wherein the first blood pressure is a maximum blood pressure, the second blood pressure is a minimum blood pressure. The estimation unit estimates an estimated value of the minimum blood pressure, based on a value of a function of the maximum blood pressure and the pulse rate when a calculated value of the maximum blood pressure and a calculated value of the pulse rate are substituted into the function of the maximum blood pressure and the pulse rate including a factor SYS γ_1 × HR γ_2 in a case where the maximum blood pressure is set as SYS and the pulse rate is set as HR.

7. The blood pressure estimating apparatus according to claim 3 or 4, wherein the first blood pressure is a maximum blood pressure, the second blood pressure is a minimum blood pressure. The estimation unit estimates an estimated value of the minimum blood pressure based on a value of a function including a factor SYS γ_1 ×T γ_2 of the maximum blood pressure and the period when a calculated value of the maximum blood pressure and a calculated value of the period are substituted into the function in a case where the maximum blood pressure is set as SYS and the period is set as T.

8. The blood pressure estimating apparatus according to any one of claims 1 to 4, wherein the first blood pressure is a minimum blood pressure, the second blood pressure is a maximum blood pressure.

9. The blood pressure estimating apparatus according to claim 1 or 2, wherein the first blood pressure is a minimum blood pressure, the second blood pressure is a maximum blood pressure. The estimation unit estimates an estimated value of the maximum blood pressure, based on a value of a function including factors DIA and HR when a calculated value of the minimum blood pressure and a calculated value of the pulse rate are substituted into the function of the minimum blood pressure and the pulse rate with the minimum blood pressure set as DIA and the pulse rate set as HR γ_1 × HR γ_2 .

10. The blood pressure estimating apparatus according to claim 3 or 4, wherein the first blood pressure is a minimum blood pressure, the second blood pressure is a maximum blood pressure. The estimation unit estimates an estimated value of the maximum blood pressure based on a value of a function including a factor DIA γ_1 × T γ_2 when a calculated value of the minimum blood pressure and a calculated value of the period are substituted into the function of the minimum blood pressure and the period with the minimum blood pressure set as DIA and the period set as T.

11. The blood pressure estimating apparatus according to any one of claims 1 to 4, wherein the calculating section calculates a calculated value of the second blood pressure from the biological information, the estimating section estimates an estimated value of the first blood pressure based on the calculated value of the second blood pressure and a calculated value of the pulse rate, the blood pressure estimating apparatus further comprises a correcting section that acquires a corrected value of the first blood pressure based on the calculated value of the first blood pressure and the estimated value of the first blood pressure, and acquires a corrected value of the second blood pressure based on the calculated value of the second blood pressure and the estimated value of the second blood pressure.

12. The blood pressure estimating apparatus according to any one of claims 1 to 4, wherein the calculating section calculates a calculated value of the second blood pressure from the biological information, the estimating section estimates an estimated value of the first blood pressure based on the calculated value of the second blood pressure and a calculated value of the period, the blood pressure estimating apparatus further comprises a correcting section that acquires a corrected value of the first blood pressure based on the calculated value of the first blood pressure and the estimated value of the first blood pressure, and acquires a corrected value of the second blood pressure based on the calculated value of the second blood pressure and the estimated value of the second blood pressure. The blood pressure estimation device further includes a correction section that obtains a corrected value of the first blood pressure from the calculated value of the first blood pressure and the estimated value of the first blood pressure, and obtains a corrected value of the second blood pressure from the calculated value of the second blood pressure and the estimated value of the second blood pressure.

13. A blood pressure estimation method characterized by comprising: including: calculating a calculated value of a first blood pressure and a calculated value of a pulse rate from biological information; and estimating an estimated value of a second blood pressure different from the first blood pressure from the calculated value of the first blood pressure and the calculated value of the pulse rate.

14. A blood pressure estimation method characterized by comprising: including: calculating a calculated value of a first blood pressure and a calculated value of a period from biological information; and estimating an estimated value of a second blood pressure different from the first blood pressure from the calculated value of the first blood pressure and the calculated value of the period.

15. A computer-readable recording medium, characterized by comprising: a program causing a computer to execute: calculating a calculated value of a first blood pressure and a calculated value of a pulse rate from biological information; and estimating an estimated value of a second blood pressure different from the first blood pressure from the calculated value of the first blood pressure and the calculated value of the pulse rate.

16. A computer-readable recording medium, characterized by a program causing a computer to execute: calculating a calculated value of a first blood pressure and a calculated value of a period from biological information; and estimating an estimated value of a second blood pressure different from the first blood pressure from the calculated value of the first blood pressure and the calculated value of the period.

17. A blood pressure estimation method characterized by comprising: including: obtaining a plurality of measurement value groups each including a measurement value of a first blood pressure, a measurement value of a pulse rate, and a measurement value of a second blood pressure different from the first blood pressure by a sphygmomanometer; creating a function of the first blood pressure and the pulse rate from the plurality of measurement value groups; calculating a calculated value of the first blood pressure and a calculated value of the pulse rate from biological information; and estimating an estimated value of the second blood pressure from a value of the function when the calculated value of the first blood pressure and the calculated value of the pulse rate are substituted into the function.

18. A blood pressure estimation method characterized by comprising: including: obtaining a plurality of measurement value groups each including a measurement value of a first blood pressure, a measurement value of a period, and a measurement value of a second blood pressure different from the first blood pressure by a sphygmomanometer; creating a function of the first blood pressure and the period from the plurality of measurement value groups; calculating a calculated value of the first blood pressure and a calculated value of the period from biological information; and estimating an estimated value of the second blood pressure from a value of the function when the calculated value of the first blood pressure and the calculated value of the period are substituted into the function.

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