Blood pressure monitoring device

Abstract

A blood pressure monitoring device capable of reducing a burden on a living body and estimating blood pressure at a short time interval is provided. According to the blood pressure monitoring device (10), an intrinsic relationship generating section (92) generates an intrinsic relationship of a living body among a blood pressure value AP, a compression pressure Pc, and a pulse wave propagation speed PWV by applying squared values of the pulse wave propagation speeds respectively detected at a plurality of compression pressures Pc in a low pressure range lower than a minimum blood pressure value DAP of the living body 2 a measured blood pressure value AP to a pre-stored linear relationship between a transmural pressure of an artery (= blood pressure value AP - compression pressure Pc) R actual compression pressures PcH1 and PcH2 in the low pressure range and actual pulse wave propagation speeds PWV1 and PWV2 in the low pressure range, thereby generating an intrinsic relationship of a living body among a blood pressure value AP, a compression pressure Pc, and a pulse wave propagation speed PWV, and a blood pressure estimating section (94) calculates an estimated blood pressure value Ape of the living body by sequentially applying actual compression pressures PcHm and pulse wave propagation speeds PWVm obtained in the low pressure range to the intrinsic relationship.

Description

Technical Field

[0001] The present invention relates to a blood pressure monitoring device having a compression band wrapped around a compressed area, wherein the compressed area is a living limb. Background Technology

[0002] In commonly used non-invasive blood pressure measuring devices, the blood pressure value of the subject is determined based on the change in the pressure pulse wave obtained as a pressure vibration of the compression band during the blood pressure reduction period. The blood pressure reduction period begins from the time when the pressure generated by the compression band rises above the subject's highest blood pressure value. For example, the automatic blood pressure measuring device described in Patent Document 1 is such a device.

[0003] In the automatic blood pressure measuring device described in Patent Document 1, a compression belt with three inflatable bags forming three independent air chambers is used. After the pressure generated by the compression belt rises to a target pressure value set higher than the highest blood pressure value of a living organism, the highest and lowest blood pressure values ​​are determined based on the change in amplitude of the pulse wave signal collected during the depressurization period, which is the period up to the measurement end pressure value set lower than the lowest blood pressure value of a living organism. Alternatively, the highest blood pressure value is determined based on the amplitude ratio of two pulse wave signals collected from two inflatable bags during the depressurization period, and the lowest blood pressure value is determined based on the time difference between the two pulse wave signals.

[0004] Existing technical documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2012-071059 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] However, according to the aforementioned conventional blood pressure measuring devices, the pressure of the compression band can rise to a target pressure value set higher than the highest blood pressure value of the living individual. Therefore, the pressure generated by the compression band can be increased to the point where arterial blood flow in the limbs wrapped with the band stops, resulting in the following drawbacks: the degree of compression can cause considerable anxiety and stress to the living individual. For example, the constricting force generated by the compression band can be increased to the point where arterial blood flow in the living individual's limbs stops, causing anxiety and making the living individual's psychological state unstable during measurement, thus compromising the accuracy of the blood pressure measurement. Furthermore, when continuously monitoring the blood pressure of a living individual with 24 hours of free movement, the stress caused by the increased constricting force generated by the compression band to the point where arterial blood flow in the living individual's limbs stops is too great, making it impossible to obtain accurate blood pressure measurements under free movement conditions. Additionally, there are situations where a compression band is needed to stop blood flow at the highest blood pressure value in a living organism, and then the compression pressure is reduced to the lowest blood pressure value in a living organism. This intermittent measurement takes time, the measurement is discontinuous, and it is impossible to detect blood pressure changes over shorter periods.

[0008] The present invention was made against the background of the above situation, and its object is to provide a blood pressure monitoring device that can reduce the burden on the living body in continuous blood pressure measurement and the like.

[0009] Technical solutions for solving the problem

[0010] After studying the relationship between the compressive pressure generated by the compression band and the pulse wave velocity of the artery, the inventors discovered that within a range where the compressive pressure is lower than the lowest blood pressure value in a living organism, the relationship between the transmural pressure (intra-arterial blood pressure - compressive pressure) and the square of the pulse wave velocity is represented by a regression line. Furthermore, based on this regression line, the actual blood pressure value of the living organism, the actual compressive pressure, and the pulse wave velocity, an inherent relationship was generated between the highest and lowest blood pressure values, or the highest and lowest blood pressure values, and the correlation values ​​between the compressive pressure and the pulse wave velocity. It was found that when multiple sets of actual compressive pressures and pulse wave velocities are applied to this inherent relationship, the blood pressure value of the living organism can be estimated. This invention is based on this insight.

[0011] That is, the essence of the first invention is a blood pressure monitoring device comprising a compression band having a plurality of inflatable bags forming independent air chambers connected in the width direction, which are wrapped around the compression site of the subject to compress the subject's artery. The blood pressure monitoring device repeatedly estimates the subject's estimated blood pressure value. The blood pressure monitoring device includes: a linear relationship storage unit storing a pre-stored linear relationship between the square of the pulse wave propagation velocity detected at multiple compression pressures of the compression band and multiple transmural pressures of the artery in a low-pressure range lower than the lowest blood pressure value of a living organism, wherein the transmural pressure is the pressure difference between the blood pressure value in the artery and the compression pressure of the compression band; and a blood pressure measurement unit based on compression pressure higher than the subject's highest blood pressure value applied to the subject. The test includes: a pulse synchronization wave obtained from the artery during the blood pressure reduction process after compression of the site; a determination of the subject's actual blood pressure value; an inherent relationship generation unit that, for the subject, applies the actual blood pressure value, the actual compression pressure in the low-pressure zone, and the actual pulse wave propagation velocity based on the propagation time between pulse waves obtained under the actual compression pressure to the linear relationship, thereby generating an inherent relationship between the subject's actual blood pressure value, the actual compression pressure, and the actual pulse wave propagation velocity; and a blood pressure estimation unit that, for the subject, applies the actual compression pressure in the low-pressure zone and the actual pulse wave propagation velocity obtained under the actual compression pressure to the inherent relationship, thereby estimating the estimated blood pressure value.

[0012] As the essence of the second invention, in the first invention, the estimated blood pressure value estimated by the blood pressure estimation unit is the estimated minimum blood pressure value DAPe of the subject. When the pulse wave propagation velocity of the living body is set to PWV, the minimum blood pressure value of the living body is set to DAP, and the compression pressure of the living body is set to Pc, the linear relationship is a regression line expressed by the following formula (1).

[0013] PWV 2 =s·(DAP-Pc)+i···(1)

[0014] Where s represents the slope of the regression line and i represents the intercept of the regression line.

[0015] As the essence of the third invention, in the second invention, when i D and s D When used as a measured correction value, the inherent relationship of the measured subject is represented by the following equation (2), where i D and s DThe actual pulse wave propagation velocity (PWV) is obtained by substituting the lowest blood pressure value measured for the subject into the two equations represented by equation (1), respectively, as DAP; the different actual compression pressures within the low-pressure range into Pc; and the propagation time between the minimum parts of the pulse wave obtained according to the different actual compression pressures. D When used as a PWV, it is obtained as a solution to the unknowns i and s respectively.

[0016] DAPe = PWV D 2 / s D -i D / s D +Pc···(2)

[0017] As the essence of the fourth invention, in the third invention, the propagation time between the minimum portions of the pulse wave obtained according to the actual pressure is the propagation time between the peaks generated corresponding to the rising points of the pulse wave obtained according to the actual pressure in the second differential waveform of the pulse wave obtained according to the actual pressure.

[0018] As the essence of the fifth invention, in the third or fourth invention, the blood pressure estimation unit includes a minimum blood pressure estimation unit, which, for the subject, successively applies the actual compression pressure in the low-pressure range and the actual pulse wave propagation velocity obtained under the actual compression pressure to the inherent relationship of equation (2), thereby estimating the estimated minimum blood pressure value.

[0019] As the essence of the sixth invention, in the first invention, the estimated blood pressure value estimated by the blood pressure estimation unit is the estimated maximum blood pressure value SAPe of the subject. When the pulse wave propagation velocity of the living body is set to PWV, the maximum blood pressure value of the living body is set to SAP, and the compression pressure of the living body is set to Pc, the linear relationship is a regression line represented by the following equation (3).

[0020] PWV 2 =s·(SAP-Pc)+i···(3)

[0021] Where s represents the slope of the regression line and i represents the intercept of the regression line.

[0022] As the essence of the seventh invention, in the sixth invention, when i S and s S When used as a measured correction value, the inherent relationship of the measured subject is represented by the following equation (4), where i S and s SThe actual pulse wave propagation velocity (PWV) is obtained by substituting the highest blood pressure value measured for the subject into the two equations represented by equation (3), respectively, into the different actual compression pressures within the low-pressure range, respectively, into the actual pulse wave propagation velocity (Pc), respectively, into the propagation time between the maxima of the pulse wave obtained according to the different actual compression pressures. S When used as a PWV, it is obtained as a solution to the unknowns i and s.

[0023] SAPe = PWV S 2 / s S -i S / s S +Pc···(4)

[0024] As the essence of the eighth invention, in the seventh invention, the propagation time between the maxima of the pulse waves obtained according to the actual pressure is the propagation time between the maxima of the pulse waves obtained according to the actual pressure.

[0025] As the essence of the ninth invention, in the seventh or eighth invention, the blood pressure estimation unit includes a maximum blood pressure estimation unit, which, for the subject, successively applies the actual compression pressure in the low-pressure range and the actual pulse wave propagation velocity obtained under the actual compression pressure to the inherent relationship of equation (4), thereby estimating the estimated maximum blood pressure value.

[0026] As the essence of the tenth invention, in the first invention, the estimated blood pressure value estimated by the blood pressure estimation unit is the estimated notch blood pressure value DNAPe of the subject, which is the pressure at the notch formed locally after the maximum part of the pulse wave obtained according to the actual pressure. When the pulse wave propagation velocity of the living body is set as PWV, the notch blood pressure value of the living body is set as DNAP, and the pressure of the living body is set as Pc, the linear relationship is a regression line represented by the following equation (5).

[0027] PWV 2 =s·(DNAP-Pc)+i···(5)

[0028] Where s represents the slope of the regression line and i represents the intercept of the regression line.

[0029] As the essence of the 11th invention, in the 10th invention, when i DN and s DN When used as a measured correction value, the inherent relationship of the measured subject is represented by the following equation (6), where i DN and s DNThe actual pulse wave propagation velocity (PWV) is obtained by substituting the measured notched blood pressure value for the subject into the two equations represented by Equation (5), respectively, into the different actual compression pressures within the low-pressure range, respectively, into the two equations, respectively, and into the actual pulse wave propagation velocity (PWV) obtained based on the propagation time between the notched parts of the pulse wave obtained according to the different actual compression pressures. DN When used as a PWV, it is obtained as a solution to the unknowns i and s.

[0030] DNAPe = PWV DN 2 / s DN -i DN / s DN +Pc···(6)

[0031] As the essence of the 12th invention, in the 11th invention, the propagation time between the notches of the pulse waves obtained according to the actual pressure is the propagation time between the apexes generated after the time point corresponding to the maximum portion of the pulse waves obtained according to the actual pressure in the second differential waveform of the pulse waves obtained according to the actual pressure.

[0032] As the essence of the 13th invention, in the 11th or 12th invention, the blood pressure estimation unit includes a notch blood pressure estimation unit, which, for the subject, successively applies the actual compression pressure in the low-pressure range and the actual pulse wave propagation velocity obtained under the actual compression pressure to the inherent relationship of equation (6), thereby estimating the estimated notch blood pressure value.

[0033] As the essence of the 14th invention, in the 13th invention, the blood pressure estimation unit includes: a minimum blood pressure estimation unit, which, for the subject, successively applies the actual compression pressure in the low-pressure zone and the actual pulse wave propagation velocity obtained under the actual compression pressure to the inherent relationship between the minimum blood pressure value measured for the subject, the actual compression pressure in the low-pressure zone, and the actual pulse wave propagation velocity in the low-pressure zone, thereby estimating the estimated minimum blood pressure value of the subject; and a maximum blood pressure estimation unit, which, based on the estimated minimum blood pressure value estimated by the minimum blood pressure estimation unit and the estimated notch blood pressure value estimated by the notch blood pressure estimation unit, generates a relationship between the pulse wave magnitude in the low-pressure zone and the estimated blood pressure value, and estimates the estimated maximum blood pressure value by applying the successively obtained maximum value of the actual pulse wave to the relationship.

[0034] As the essence of the 15th invention, any one of the 1st to 14th inventions includes: a pressure control unit that reduces the pressure of multiple pressures in the low-pressure zone in stages, thereby forming multiple zones that are temporarily maintained at a certain value in the low-pressure zone; a pulse wave extraction unit that extracts pulse waves as pressure vibrations generated synchronously with the pulse in the multiple expansion bags under the pressure in the multiple zones; and a pulse wave propagation velocity calculation unit that calculates the pulse wave propagation velocity based on the time difference of the pulse waves obtained in the multiple zones and the distance between the multiple expansion bags.

[0035] As the essence of the 16th invention, in any of the 1st to 15th inventions, the compression band has independent upstream expansion bags, intermediate expansion bags, and downstream expansion bags that are wound around the compressed part of the living body and connected in the width direction to compress the compressed part of the living body respectively, and the artery in the compressed part is compressed by the upstream expansion bag, the intermediate expansion bag, and the downstream expansion bag respectively with the same compression pressure.

[0036] The effects of the invention

[0037] The blood pressure monitoring device according to the first invention includes: a linear relationship storage unit that stores a pre-stored linear relationship between the square of the pulse wave propagation velocity detected at multiple compression pressures of the compression band in a low-pressure zone lower than the lowest blood pressure value of a living person and multiple transmural pressures of the artery, wherein the transmural pressure is the pressure difference between the blood pressure value in the artery and the compression pressure of the compression band; an inherent relationship generation unit that, for the subject, applies the actual blood pressure value, the actual compression pressure in the low-pressure zone, and the actual pulse wave propagation velocity obtained based on the propagation time between pulse waves obtained at the actual compression pressure to the linear relationship, thereby generating an inherent relationship between the actual blood pressure value, the actual compression pressure, and the actual pulse wave propagation velocity of the subject with respect to the subject; and a blood pressure estimation unit that, for the subject, applies the actual compression pressure in the low-pressure zone and the actual pulse wave propagation velocity obtained at the actual compression pressure to the inherent relationship with respect to the subject, thereby estimating the estimated blood pressure value. Therefore, in addition to measuring the actual blood pressure value of the subject through the blood pressure measuring unit, when estimating the blood pressure value, the pressure generated by the compression belt is set to a value lower than the subject's lowest blood pressure value. Thus, the burden on the subject can be reduced, and more continuous blood pressure measurements can be performed.

[0038] According to the blood pressure monitoring device of the second and third inventions, in the inherent relationship generation unit, the inherent relationship between the minimum blood pressure value, the actual compression pressure, and the pulse wave propagation velocity of the subject is generated using the minimum blood pressure value measured for the subject, the actual compression pressure, and the pulse wave propagation velocity obtained based on the propagation time between the smallest parts of the pulse wave obtained under the actual compression pressure. Therefore, the blood pressure estimation unit can easily estimate the estimated minimum blood pressure value of the subject by applying the actual compression pressure obtained in a low-pressure range lower than the minimum blood pressure value and the pulse wave propagation velocity obtained based on the time difference between the smallest parts of the pulse wave obtained under the actual compression pressure to the inherent relationship generated by the inherent relationship generation unit.

[0039] According to the blood pressure monitoring device of the fourth invention, the propagation time between the minimum portions of the pulse wave obtained according to the actual compression pressure is the propagation time between the apex generated in the second differential waveform of the pulse wave obtained according to the actual compression pressure and the apex corresponding to the rising point of the pulse wave obtained according to the actual compression pressure. In this way, the propagation time between the minimum portions of the pulse wave can be easily obtained, and the estimation accuracy of the minimum blood pressure value is improved.

[0040] According to the blood pressure monitoring device of the fifth invention, the blood pressure estimation unit includes a minimum blood pressure estimation unit, which applies the actual compression pressure in the low-pressure range and the actual pulse wave propagation velocity obtained under the actual compression pressure to the inherent relationship of Equation (2) for the subject, thereby estimating the estimated minimum blood pressure value. Therefore, the estimated minimum blood pressure value of the subject can be easily estimated.

[0041] According to the blood pressure monitoring device of the 6th and 7th inventions, in the inherent relationship generation unit, an inherent relationship between the highest blood pressure value, the actual compression pressure, and the pulse wave propagation velocity is generated for the subject using the highest blood pressure value measured for the subject, the actual compression pressure, and the pulse wave propagation velocity obtained based on the propagation time between the maxima of the pulse wave obtained at the actual compression pressure. Therefore, the blood pressure estimation unit can estimate the estimated highest blood pressure value of the subject by applying the actual compression pressure obtained in a low-pressure range lower than the lowest blood pressure value and the pulse wave propagation velocity obtained based on the time difference between the maxima of the pulse wave obtained at the actual compression pressure to the inherent relationship generated by the inherent relationship generation unit.

[0042] According to the blood pressure monitoring device of the 8th invention, the propagation time between the maxima of the pulse wave obtained according to the actual compression pressure is the propagation time between the maxima of the pulse wave obtained according to the actual compression pressure. This makes it easy to obtain the propagation time between the maxima of the pulse wave, thus improving the accuracy of estimating the maximum blood pressure value.

[0043] According to the blood pressure monitoring device of the 9th invention, the blood pressure estimation unit includes a maximum blood pressure estimation unit, which applies the actual compression pressure in the low-pressure range and the actual pulse wave propagation velocity obtained under the actual compression pressure to the inherent relationship of Equation (4) for the subject, thereby estimating the estimated maximum blood pressure value. Therefore, the estimated maximum blood pressure value of the subject can be easily estimated.

[0044] According to the blood pressure monitoring device of the 10th and 11th inventions, in the inherent relationship generation unit, the inherent relationship between the notched blood pressure value, the actual compression pressure, and the pulse wave propagation velocity, measured for the subject, is generated using the notched blood pressure value, the actual compression pressure, and the pulse wave propagation velocity obtained based on the propagation time between the notched portions of the pulse wave obtained under the actual compression pressure. Therefore, the blood pressure estimation unit can easily estimate the estimated notched blood pressure value of the subject by applying the actual compression pressure obtained in a low-pressure range lower than the lowest blood pressure value and the pulse wave propagation velocity obtained based on the time difference between the notched portions of the pulse wave obtained under the actual compression pressure to the relationship inherent to the living body generated by the inherent relationship generation unit.

[0045] According to the blood pressure monitoring device of the 12th invention, the propagation time between the notched portions of the pulse wave obtained according to the actual compression pressure is the propagation time between the apexes generated after the time point corresponding to the maximum portion of the pulse wave obtained according to the actual compression pressure in the second differential waveform of the pulse wave obtained according to the actual compression pressure. In this way, the propagation time between the notched portions of the pulse wave can be easily obtained, and the estimation accuracy of the notched blood pressure value is improved.

[0046] According to the blood pressure monitoring device of the 13th invention, the blood pressure estimation unit includes a notch blood pressure estimation unit, which applies the actual compression pressure in the low-pressure range and the actual pulse wave propagation velocity obtained under the actual compression pressure to the inherent relationship of Equation (6) for the subject, thereby estimating the estimated notch blood pressure value. Therefore, the estimated notch blood pressure value of the subject can be easily estimated.

[0047] According to the blood pressure monitoring device of the 14th invention, the blood pressure estimation unit includes: a minimum blood pressure estimation unit, which, for the subject, successively applies the actual compression pressure in the low-pressure zone and the actual pulse wave propagation velocity obtained under the actual compression pressure to the inherent relationship between the minimum blood pressure value measured for the subject, the actual compression pressure in the low-pressure zone, and the actual pulse wave propagation velocity in the low-pressure zone, thereby estimating the estimated minimum blood pressure value of the subject; and a maximum blood pressure estimation unit, which, based on the estimated minimum blood pressure value estimated by the minimum blood pressure estimation unit and the estimated notch blood pressure value estimated by the notch blood pressure estimation unit, generates a relationship between the pulse wave magnitude in the low-pressure zone and the estimated blood pressure value, and estimates the estimated maximum blood pressure value by applying the successively obtained maximum value of the actual pulse wave to the relationship. Therefore, the estimated maximum blood pressure value of the subject can be easily estimated.

[0048] The blood pressure monitoring device according to the 15th invention includes: a pressure control unit that reduces multiple pressures within a low-pressure zone in stages, thereby creating multiple zones that are temporarily maintained at a certain value within the low-pressure zone; a pulse wave extraction unit that extracts pulse waves as pressure vibrations generated synchronously with the pulse in multiple expansion bags under pressure in the multiple zones; and a pulse wave propagation velocity calculation unit that calculates the pulse wave propagation velocity based on the time difference of the pulse waves obtained in the multiple zones and the distance between the multiple expansion bags. Therefore, the pulse waves obtained in the zones where the pressure is maintained at a certain value are waveforms without distortion caused by pressure fluctuations, thus the pulse wave propagation velocity can be accurately obtained, and the inherent relationship can be accurately calculated.

[0049] According to the blood pressure monitoring device of the 16th invention, the compression band has independent upstream expansion pockets, intermediate expansion pockets, and downstream expansion pockets that are wound around the compressed part of a living body and connected in the width direction to compress the compressed part of the living body, respectively. The upstream expansion pocket, the intermediate expansion pocket, and the downstream expansion pocket each apply the same pressure to the artery within the compressed part. Therefore, it has the advantage of simultaneously measuring blood pressure and detecting pulse wave velocity using compression of the limbs of a living body. Attached Figure Description

[0050] Figure 1 This is a block diagram illustrating the configuration of a blood pressure monitoring device as an embodiment of the present invention.

[0051] Figure 2 It is represented by removing a portion of the outer peripheral surface. Figure 1 Diagram of the compression zone.

[0052] Figure 3 It means Figure 2 A top view of the upstream expansion bag, intermediate expansion bag, and downstream expansion bag within the compression zone.

[0053] Figure 4 yes Figure 3 The IV-IV sectional view is a diagram showing the upstream expansion bag, the middle expansion bag, and the downstream expansion bag cut off in the width direction.

[0054] Figure 5 It is used for Figure 1 The functional block diagram illustrates the main control functions of the electronic control device.

[0055] Figure 6 It is by Figure 5 The timeline of the main parts of the pressure control work performed by the pressure control unit is explained.

[0056] Figure 7 This graph represents the experimental results conducted by the inventors, showing the squared value of pulse wave velocity (PWV) as the compression pressure Pc varied across the entire range below the lowest blood pressure value (DAP). 2 Two-dimensional coordinates relating to Ln((DAP-Pc) / Po).

[0057] Figure 8 It involves combining two-dimensional coordinate data with the regression line y and the coefficient of determination R. 2 The graph shown together represents the results of Experiment No. 1 conducted by the inventors on a predetermined living animal (dog) regarding the relationship between transmural pressure and pulse wave propagation velocity.

[0058] Figure 9 Is with Figure 8 Similarly, it indicates making and Figure 8 A graph showing the results of Experiment No. 2 conducted by the inventors when the blood pressure of the same living organism increased.

[0059] Figure 10 Is with Figure 8 Similarly, it indicates making and Figure 8 and Figure 9 A graph showing the results of Experiment No. 3 conducted by the inventors when the blood pressure of the same living organism increased.

[0060] Figure 11 Is with Figure 8 Similarly, it indicates making and Figures 8-10 A graph showing the results of Experiment No. 4 conducted by the inventors when the blood pressure of the same living organism increased.

[0061] Figure 12Is with Figure 8 Similarly, it indicates making and Figures 8-11 The figure shows the results of Experiment No. 5 conducted by the inventors when the blood pressure of the same living organism was restored to its original state.

[0062] Figure 13 Is with Figure 8 Similarly, it indicates making and Figures 8-12 A graph showing the results of Experiment No. 6 conducted by the inventors when the blood pressure of the same living organism decreased.

[0063] Figure 14 Is with Figure 8 Similarly, it indicates making and Figures 8 to 13 A graph showing the results of Experiment No. 7 conducted by the inventors when the blood pressure of the same living organism decreased.

[0064] Figure 15 Is with Figure 8 Similarly, it indicates making and Figures 8 to 14 The figure shows the results of Experiment No. 8 conducted by the inventors when the blood pressure of the same living organism returned to its original state.

[0065] Figure 16 It is a diagram in which the pulse wave and its first differential waveform are superimposed on the same time axis at the same time. It is a diagram showing the correspondence between the minimum part of the pulse wave (MWLMP), the maximum part of the pulse wave (MWLXP), and the notch part of the pulse wave (MWLNP) and the zero crossover points ZX1, ZX2, and ZX3 of the first differential waveform of the pulse wave.

[0066] Figure 17 It is a diagram that represents the pulse wave and its second differential waveform on a common time axis at the same time phase. It is a diagram that shows the correspondence between the minimum part of the pulse wave (MWLMP), the notched part of the pulse wave (MWLNP), and the maximum part of the pulse wave (MWLXP) and the vertices ZT1, ZT3, and ZT2 of the second differential waveform of the pulse wave, which are the same time points as MWLXP.

[0067] Figure 18 This is a graph showing the experimental results of the inventors, etc., and it shows the results obtained through... Figure 1 A graph showing the correlation between the estimated minimum blood pressure value and the measured minimum blood pressure value, based on the control operation of the electronic control device.

[0068] Figure 19 Yes Figure 1 A flowchart illustrating the control operation of the electronic control device.

[0069] Figure 20 This is a functional block diagram illustrating the main parts of the control function of the electronic control device in other embodiments of the present invention, and is related to... Figure 5A fairly accurate diagram.

[0070] Figure 21 It involves combining two-dimensional coordinate data with the regression line y and the coefficient of determination R. 2 The graph shown together represents the results of Experiment No. 9 conducted by the inventors on the relationship between transwall pressure and pulse wave propagation velocity in a predetermined living organism.

[0071] Figure 22 This is a graph showing the correlation between notched blood pressure values ​​(DNAP) directly measured using a catheter in a pre-selected living animal (dog) and the measured average blood pressure values.

[0072] Figure 23 Is Figure 20 The figure in the embodiment illustrates the relationship between the minimum, notch, and maximum portions of the pulse wave obtained in the monitoring pressure maintenance interval and the estimated minimum blood pressure value, estimated notch blood pressure value, and estimated maximum blood pressure value.

[0073] Figure 24 Is Figure 20 The embodiment shows a graph representing the relationship pre-determined for the living organism to be measured in order to estimate the estimated maximum blood pressure value.

[0074] Figure 25 Yes Figure 20 The flowchart illustrates the main parts of the control operation of the electronic control device in the embodiment. Detailed Implementation

[0075] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, in the following embodiments, the drawings have been appropriately simplified or modified, and the dimensional ratios and shapes of the parts are not necessarily depicted accurately.

[0076] Example 1

[0077] Figure 1 A blood pressure monitoring device 10 (automatic blood pressure measuring device) functioning as a blood pressure estimation device, also shown as an example of the present invention, is illustrated. The blood pressure monitoring device 10 includes a compression band 12 for the upper arm, which is wrapped around a compressed area, such as the upper arm 16, which is a living limb such as an arm or ankle of the subject 14. The blood pressure monitoring device 10 extracts pulse waves sequentially during the process of depressing the compression pressure Pc of the compression band 12, which has been raised to a value sufficient to stop blood flow in the artery 18 within the upper arm 16. Based on the information obtained from the pulse waves, the device measures the highest blood pressure value SAP and the lowest blood pressure value DAP of the living subject 14, wherein the pulse waves are pressure vibrations within the compression pressure Pc of the compression band 12 generated in response to changes in the volume of the artery 18.

[0078] Figure 2 This diagram shows the compression band 12 by removing a portion of the outer peripheral nonwoven fabric 20a. (See diagram.) Figure 2 As shown, the compression band 12 includes: a strip-shaped outer bag 20, comprising an outer peripheral nonwoven fabric 20a and an inner peripheral nonwoven fabric 20b made of synthetic resin fibers laminated together with synthetic resins such as PVC (polyvinyl chloride); and an upstream expansion bag 22, a middle expansion bag 24, and a downstream expansion bag 26, which are sequentially housed within the strip-shaped outer bag 20 in the width direction. These are made of, for example, flexible sheets such as soft polyvinyl chloride sheets, and are capable of independently compressing the upper arm 16. The compression band 12 is detachably attached to a face fastener 28a installed at the end of the inner peripheral nonwoven fabric 20b by a pile tuft 28b, which is attached to the end of the outer peripheral nonwoven fabric 20a, thereby being worn on the upper arm 16 in a detachable manner.

[0079] The upstream expansion bag 22, the intermediate expansion bag 24, and the downstream expansion bag 26 are connected in the width direction of the elongated compression belt 12, each having an independent air chamber for compressing the upper arm 16, and having pipe connectors 32, 34, and 36 on the outer peripheral side. These pipe connectors 32, 34, and 36 are exposed on the outer peripheral surface of the compression belt 12 through the nonwoven fabric 20a on the outer peripheral side.

[0080] Figure 3 This is a top view showing the upstream expansion bag 22, the intermediate expansion bag 24, and the downstream expansion bag 26 within the compression belt 12. Figure 4 yes Figure 3 The IV-IV sectional view shows the upstream expansion bag 22, the intermediate expansion bag 24, and the downstream expansion bag 26, which are used to detect pulse waves and are each formed into an elongated shape. The pulse waves are pressure vibrations generated in response to changes in the volume of the artery 18 compressed by the upstream expansion bags 22, the intermediate expansion bag 24, and the downstream expansion bag 26. The upstream expansion bags 22 and 26 are arranged adjacent to the sides of the intermediate expansion bag 24, and the intermediate expansion bag 24 is positioned at the center of the compression band 12 in the width direction, sandwiched between the upstream and downstream expansion bags 26. The center of the upstream expansion bag 22 is L12 away from the center of the intermediate expansion bag 24, and the center of the upstream expansion bag 22 is L13 away from the center of the downstream expansion bag 26. Furthermore, with the compression belt 12 wound around the upper arm 16, the upstream expansion bag 22 and the downstream expansion bag 26 are positioned at a predetermined interval in the length direction of the upper arm 16. In addition, the intermediate expansion bag 24 is arranged in a continuous manner between the upstream expansion bag 22 and the downstream expansion bag 26 in the length direction of the upper arm 16.

[0081] The intermediate expansion bag 24 has side edges with so-called gusseted structures on both sides. That is, a pair of folded-in grooves 24f and 24g are formed at both ends of the upper arm 16 of the intermediate expansion bag 24 in the length direction, i.e., in the width direction of the compression belt 12. These pair of folded-in grooves 24f and 24g are formed by flexible sheets that are folded in in a direction that approaches each other so that they become deeper as they approach each other. Furthermore, the ends 22a and 26a of the upstream expansion bag 22 and the downstream expansion bag 26 on the side adjacent to the intermediate expansion bag 24 are respectively inserted into the pair of folded-in grooves 24f and 24g. Thus, the structure becomes an overlapping structure in which the end 24a of the intermediate expansion bag 24 and the end 22a of the upstream expansion bag 22 overlap each other, and the end 24b of the intermediate expansion bag 24 and the end 26a of the downstream expansion bag 26 overlap each other. Therefore, when the upstream expansion bag 22, the intermediate expansion bag 24 and the downstream expansion bag 26 press the upper arm 16 with equal pressure, a uniform pressure distribution can also be obtained near the boundary of those expansion bags.

[0082] The upstream expansion bag 22 and the downstream expansion bag 26 also have side edges with gusseted structures at their ends 22b and 26b opposite to the intermediate expansion bag 24. Specifically, a fold-in groove 22f is formed at the end 22b of the upstream expansion bag 22 opposite to the intermediate expansion bag 24. This fold-in groove 22f is formed of a flexible sheet that folds inward in a direction of approach, becoming deeper as they approach each other. Similarly, a fold-in groove 26g is formed at the end 26b of the downstream expansion bag 26 opposite to the intermediate expansion bag 24. This fold-in groove 26g is formed of a flexible sheet that folds inward in a direction of approach, becoming deeper as they approach each other. The sheet constituting the fold-in groove 22f is connected to its opposite side, i.e., the portion on the side of the intermediate expansion bag 24, via a connecting piece 38 with a through hole disposed within the upstream expansion bag 22, so as not to bulge out in the width direction of the compression band 12. Similarly, the sheet forming the folded groove 26g is connected to its opposite side, i.e. the part on the side of the middle expansion bag 24, via a connecting piece 40 with a through hole disposed in the downstream expansion bag 26.

[0083] Therefore, the ends 22b and 26b of the upstream expansion bag 22 and the downstream expansion bag 26 also obtain the same pressure Pc on the artery 18 of the upper arm 16 as the other parts, so the effective compression width of the compression band 12 in the width direction becomes equal to its width dimension. Since the compression band 12 is about 12cm wide in the width direction and has three upstream expansion bags 22, intermediate expansion bags 24 and downstream expansion bags 26 arranged in its width direction, each of them must be substantially about 4cm wide. In order to generate sufficient compression function even with such a narrow width dimension, the two ends 24a and 24b of the intermediate expansion bag 24 are designed to overlap with the ends 22a of the upstream expansion bag 22 and the ends 26a of the downstream expansion bag 26, and the ends 22b and 26b of the upstream expansion bag 22 and the downstream expansion bag 26 opposite to the intermediate expansion bag 24 are designed as the side edges of a so-called gusseted structure.

[0084] At the ends 22a and 26a of the upstream expansion bag 22 and the downstream expansion bag 26 on the side of the intermediate expansion bag 24, respectively, elongated shielding members 42n and 42m are respectively sandwiched between the inner wall surfaces of a pair of folded grooves 24f and 24g inserted therebetween, i.e., the opposing groove sides. These shielding members 42n and 42m have anisotropic rigidity, where the bending rigidity in the width direction of the compression band 12 is higher than its bending rigidity in the length direction. The shielding member 42n has the same length dimension as the overlap dimension of the upstream expansion bag 22 and the intermediate expansion bag 24. Similarly, the shielding member 42m has the same length dimension as the overlap dimension of the downstream expansion bag 26 and the intermediate expansion bag 24.

[0085] like Figure 3 and Figure 4 As shown, elongated shielding members 42n and 42m are respectively sandwiched in the outer peripheral gap between the end 22a of the upstream expansion bag 22 and the fold-in groove 24f inserted therein, and in the outer peripheral gap between the end 26a of the downstream expansion bag 26 and the fold-in groove 24g inserted therein. In this embodiment, the shielding effect of the outer peripheral gap is greater than that of the inner peripheral gap. Therefore, the elongated shielding members 42n and 42m are provided in the outer peripheral gap, but they can also be provided in both the outer peripheral gap and the inner peripheral gap.

[0086] The shielding components 42n and 42m are formed by multiple flexible hollow resin tubes 44 parallel to the length direction of the upper arm 16 (i.e., the width direction of the compression band 12), arranged in parallel to each other along the circumference of the upper arm 16 (i.e., the length direction of the compression band 12). These flexible hollow tubes 44 are connected to each other directly or indirectly via other components such as flexible sheets or adhesive tapes, formed by molding or bonding. The shielding component 42n is hooked by multiple hooks 46 located at multiple locations on the outer periphery of the end 22a on the middle expansion bag 24 side of the upstream expansion bag 22. Similarly, the shielding component 42m is hooked by multiple hooks 46 located at multiple locations on the outer periphery of the end 26a on the middle expansion bag 24 side of the downstream expansion bag 26.

[0087] return Figure 1 In the blood pressure monitoring device 10, an air pump 50, a rapid exhaust valve 52, and an exhaust control valve 54 are connected to a main pipe 56. Branches from this main pipe 56 are a first branch pipe 58 connected to the upstream expansion bag 22, a second branch pipe 62 connected to the intermediate expansion bag 24, and a third branch pipe 64 connected to the downstream expansion bag 26. The first branch pipe 58 has a first on / off valve E1 for directly opening and closing the connection between the air pump 50 and the upstream expansion bag 22. The second branch pipe 62 has a second on / off valve E2 for directly opening and closing the connection between the air pump 50 and the intermediate expansion bag 24. The third branch pipe 64 has a third on / off valve E3 for directly opening and closing the connection between the air pump 50 and the downstream expansion bag 26.

[0088] A first pressure sensor T1 for detecting the pressure value inside the upstream expansion bag 22 is connected to the first branch pipe 58; a second pressure sensor T2 for detecting the pressure value inside the intermediate expansion bag 24 is connected to the second branch pipe 62; a third pressure sensor T3 for detecting the pressure value inside the downstream expansion bag 26 is connected to the third branch pipe 64; and a fourth pressure sensor T4 for detecting the pressure Pc of the compression belt 12 is connected to the main pipe 56.

[0089] For the electronic control device 70, the first pressure sensor T1 provides an output signal representing the pressure value inside the upstream expansion bag 22, i.e., the compression pressure Pc1 of the upstream expansion bag 22; the second pressure sensor T2 provides an output signal representing the pressure value inside the intermediate expansion bag 24, i.e., the compression pressure Pc2 of the intermediate expansion bag 24; the third pressure sensor T3 provides an output signal representing the pressure value inside the downstream expansion bag 26, i.e., the compression pressure Pc3 of the downstream expansion bag 26; and the fourth pressure sensor T4 provides an output signal representing the compression pressure Pc of the compression belt 12.

[0090] The electronic control device 70 is a so-called microcomputer, including a CPU 72, RAM 74, ROM 76, a display device 78, and I / O ports (not shown). The electronic control device 70 utilizes the storage function of RAM 74 via the CPU 72 and processes input signals according to a program pre-stored in ROM 76. It responds to the operation of the blood pressure estimation start button 80 and controls the electric air pump 50, the rapid exhaust valve 52, the exhaust control valve 54, the first on / off valve E1, the second on / off valve E2, and the third on / off valve E3, thereby performing automatic blood pressure measurement control and displaying the measurement results on the display device 78.

[0091] Figure 5 This is a functional block diagram used to explain the main parts of the control functions of the electronic control device 70. Figure 5 In this process, the electronic control device 70 functionally includes a linear relationship storage unit 82, a blood pressure measurement unit 84, a compression pressure control unit 86, a pulse wave extraction unit 88, a pulse wave propagation velocity calculation unit 90, an inherent relationship generation unit 92, and a blood pressure estimation unit 94 having a minimum blood pressure estimation unit 96 and a maximum blood pressure estimation unit 98. Figure 6 This is a timeline that explains the main parts of the pressure control operation of the pressure belt 12, which is implemented by the pressure control unit 86.

[0092] The linear relation storage unit 82 pre-stores the squared values ​​of multiple pulse wave propagation velocities PWV detected under multiple compression pressures Pc of the compression band 12 in a low-pressure range lower than the lowest blood pressure value DAP of the living organism 14. 2 The stored linear relationship between the transmural pressure (AP-Pc) of artery 18, where the transmural pressure is the pressure difference between the blood pressure value AP and the compression pressure Pc within artery 18. Specifically, for the lowest blood pressure value DAP, a regression line is stored as the linear relationship represented by equation (1), and for the highest blood pressure value SAP, a regression line is stored as the linear relationship represented by equation (3).

[0093] PWV 2 =s·(DAP-Pc)+i···(1)

[0094] PWV 2 =s·(SAP-Pc)+i···(3)

[0095] Where s represents the slope of the regression line and i represents the intercept of the regression line.

[0096] The regression line described above will be explained below. Generally speaking, the Bramwell Hill formula shown in equation (7) is known for the propagation velocity of pulse waves in arteries. In equation (7), V is the volume of the artery, P is the blood pressure in the artery, and ρ is the density of the blood. Here, the arterial volume V is represented by equation (8) when the cross-sectional area of ​​the blood vessel is set as A and the distance between the expansion sacs is set as L. When the two sides of equation (8) are differentiated by A, it becomes equation (9).

[0097] PWV=√((V·dP) / (ρ·dV))···(7)

[0098] V = A·L···(8)

[0099] dV=dA·L···(9)

[0100] Furthermore, an exponential function model, including the exponential function constant Po and the coefficient α, was established for blood pressure P and blood vessel cross-sectional area A, as shown in equation (10), which was rewritten as equation (11). Here, when the density ρ is set to 1 for simplification, the relationship between pulse wave propagation velocity PWV and blood pressure value AP is expressed by equation (12) according to equations (7), (9), and (11).

[0101] P = Po·e αA ···(10)

[0102] dP=α·P·dA···(11)

[0103] PWV 2 =P·Ln(P / Po)···(12)

[0104] When the lowest blood pressure value DAP of the living body is stable, and the pressure Pc generated by the compression band 12 is varied in a pressure region (low-pressure zone) lower than the lowest blood pressure value DAP of the living body, the transmural pressure (DAP-Pc) and the pulse wave velocity PWV, which are the pressure difference applied to the vessel wall of artery 18, change successively for each pulse. Therefore, the above equation (12) is replaced by the following formula model (13) for a certain pulse.

[0105] PWV 2 =(DAP-Pc)·Ln((DAP-Pc) / Po)···(13)

[0106] Where Pc < DAP

[0107] The inventors discovered that in the above formula (13), Ln((DAP-Pc) / Po), which includes Po on the right side, and PWV on the left side... 2The relationship is that the lowest blood pressure value (DAP) is stable while the compression pressure (Pc) is in the range of 20 mmHg to 60 mmHg. Figure 7 The range B mentioned above is a fixed value. Figure 7 PWV represents the square of the pulse wave propagation velocity. 2 The two-dimensional coordinate system, with the horizontal axis representing Ln((DAP-Pc) / Po) and the vertical axis representing PwV, shows the calculation of PWV based on data obtained by measuring pulse wave velocity (PWV) when the compression pressure Pc varies across the entire range below the lowest blood pressure value DAP. 2 The curve for Ln((DAP-Pc) / Po). Furthermore, within the range B where the compression pressure Pc is sufficiently lower than the lowest blood pressure value DAP, for example, 20 mmHg to 60 mmHg, Ln((DAP-Pc) / Po) becomes approximately constant.

[0108] Furthermore, in the three-link compression band 12 having independent upstream expansion pouches 22, intermediate expansion pouches 24, and downstream expansion pouches 26 connected in the width direction, during the phased decompression process in which the compression pressure Pc is maintained at a certain pressure in different stages within a pressure region lower than the lowest blood pressure value DAP of the living body 14, the phase difference (propagation time) Δt of the rise point of the pulse wave obtained from the pair of upstream expansion pouches 22 and downstream expansion pouches 26, and the compression pressure Pc at that time, can be measured simultaneously. The distance L13 between the pair of upstream expansion pouches 22 and downstream expansion pouches 26 is known, therefore, the pulse wave propagation velocity PWV (=L13 / Δt) of each pulse wave can be calculated successively. Furthermore, when the term Ln((DAP-Pc) / Po) in the above equation (13) is set to represent a certain value κ in the pressure region (low pressure range) lower than the lowest blood pressure value DAP of the living body, for example, in the low region range where the compression pressure Pc is 20~60mmHg, equation (13) is rewritten as shown in equation (14).

[0109] PWV 2 ∝κ·(DAP-Pc)···(14)

[0110] When the relationship between pulse wave velocity (PWV) and transmural pressure (DAP-Pc) in equation (14) is further generalized, it becomes a regression line with slope s and intercept i, i.e., equation (1). When the lowest blood pressure value DAP is measured in advance for a predetermined subject... R Next, the lowest blood pressure value (DAP) of the subject will be measured. R Substituting multiple sets of pressure pressures Pc and pulse wave velocity PWV measured under different pressures within the low-pressure region (low-pressure zone) into two equations identical to equation (1), i is obtained as a solution to i and s respectively. D and sD When used as measured correction values, the inherent relationship shown in equation (2) can be obtained, where i and s are the two unknowns of those simultaneous equations.

[0111] The inventors conducted the following experiments: In the same living animal (dog), at eight time points where blood pressure varied widely due to the drug, the lowest blood pressure value (DAP) was measured using an intravascular blood pressure measuring catheter. R Furthermore, based on multiple different compression pressures Pc within low-pressure ranges lower than the lowest blood pressure in living organisms, and multiple sets of pulse wave velocities PWV measured at these compression pressures, the transmural pressure (DAP-Pc) is calculated, and the square of the transmural pressure (DAP-Pc) and pulse wave velocity PWV is calculated as PWV. 2 The regression line between them.

[0112] Figures 8-15 Based on multiple data obtained using a sphygmomanometer to measure blood pressure via an intravascular catheter at eight time points (eight experiments No. 1 to No. 8) in an experimental animal (dog) where blood pressure varied widely using a drug, the transmural pressure (DAP-Pc) was compared with the square of the pulse wave velocity (PWV). 2 The relationship is represented in a two-dimensional coordinate graph. For example... Figures 8-15 As shown, in any of the experiments No.1 to No.8 above, the coefficient of determination R of the regression line y is... 2 The values ​​ranged from 0.94 to 0.99, all close to 1, indicating a high-quality linear relationship. That is, it was confirmed that even with large variations in blood pressure, a stable regression line represented by equation (1) could be obtained.

[0113] Before generating the inherent relation through the inherent relation generation unit 92, the blood pressure measuring unit 84 measures the actual highest blood pressure value SAP of the subject. R and the actual lowest blood pressure value DAP R In this blood pressure measurement, for example, according to the well-known oscillometric method, after the pressure Pc generated by the pressure band 12 is raised to a target value higher than the subject's highest blood pressure by the pressure control unit 86, during the slow depressurization of the pressure Pc, a pulse wave that pulsates synchronously with the pulse and overlaps with the pressure Pc2 of the intermediate expansion bag 24 is detected. Based on the pressure Pc corresponding to the inflection point of the envelope connecting the maximum amplitude of this pulse wave, the highest blood pressure value SAP is determined. R and lowest blood pressure value DAP RAlternatively, in this blood pressure measurement, the actual highest blood pressure value SAP can be determined, for example, according to the well-known Korotkoff sound method, based on the compression pressure Pc when the vascular sound (Korotkoff sound) is produced and the compression pressure Pc when the vascular sound disappears. R and lowest blood pressure value DAP R The vascular sounds (Korotkoff sounds) are sounds generated synchronously with the pulse detected by the microphone during the aforementioned depressurization process. The aforementioned pulse wave and vascular sounds are pulse synchronization waves generated synchronously with the pulse of a living organism.

[0114] 86 pairs of pressure control units Figure 5 The operation of the blood pressure estimation start button 80, as shown, responds first to obtain the actual blood pressure value AP of the living subject 14. R The measurement, performed by the blood pressure measuring unit 84, involves closing the rapid exhaust valve 52 and the exhaust control valve 54, and opening the first on / off valve E1, the second on / off valve E2, and the third on / off valve E3 to activate the air pump 50. This causes the pressure Pc of the compression band 12 on the living body 14 to rapidly increase to a pressure sufficiently higher than the highest blood pressure value SAP of the living body 14, for example, a target pressure value PCM preset to 180 mmHg.

[0115] Next, the pressure control unit 86 repeatedly opens the exhaust control valve 54 at a predetermined cycle for a predetermined period, thereby slowly reducing the pressure Pc of the compression belt 12 in a step-like manner at a predetermined pressure reduction rate until the pressure Pc of the compression belt 12 becomes lower than the measurement end pressure value PCE. This ensures that during the period until the pressure Pc of the compression belt 12 reaches a pressure sufficiently lower than the lowest blood pressure value DAP of the living body 14, for example, the measurement end pressure value PCE preset to 60 mmHg, a certain number of fixed step pressures P1, P2, P3, ..., Px are maintained sequentially. For the pressure Pc of the compression belt 12 controlled in this way, the upstream expansion bag 22, the intermediate expansion bag 24, and the downstream expansion bag 26 compress the living body 14 with the same pressure Pc, but... Figure 6 The pressure Pc of the compression belt 12, detected by the fourth pressure sensor, is shown in the figure.

[0116] Next, in order to obtain the actual first pulse wave propagation velocity PWV1 and second pulse wave propagation velocity PWV2 as multiple pulse wave propagation velocities PWV of the living subject 14, the pressure control unit 86 reduces the pressure Pc in stages to sequentially form a first maintenance interval (time point tk2 to time point tk3) that temporarily maintains a certain first maintenance pressure PcH1, and a second maintenance interval (time point tk4 to time point tk5) that maintains a second maintenance pressure PcH2 lower than the first maintenance pressure PcH1. Then, using the rapid exhaust valve 52, the pressure in the upstream expansion bag 22, the intermediate expansion bag 24, and the downstream expansion bag 26 is released to atmospheric pressure. The first maintenance pressure PcH1 and the second maintenance pressure PcH2 are pressures that are sufficiently lower than the lowest blood pressure value DAP of the living subject 14, for example, preset values ​​in the range of 20 to 60 mmHg.

[0117] Furthermore, after generating the inherent relationships shown in Equations (2) and (4) as described later by the inherent relationship generation unit 92 (described later), the compression pressure control unit 86, in order to estimate the estimated maximum blood pressure value SAPe and the estimated minimum blood pressure value DAPe of the living body 14 according to Equations (2) and (4), responds to the blood pressure estimation start command (time point tm1) repeatedly issued by the electronic control device 70 at a predetermined blood pressure estimation cycle, for example, a cycle of tens of seconds to several minutes, and controls the compression pressure Pc so that a pressure sufficiently lower than the minimum blood pressure value DAP of the living body 14 being measured is maintained in the monitoring pressure maintenance interval (time point tm2 to time point tm3), for example, a certain monitoring pressure PcHm preset in the range of 20 to 60 mmHg.

[0118] When the pressure monitoring interval (time point tm2 to time point tm3) ends, the pressure control unit 86 uses the rapid exhaust valve 52 to release the pressure in the upstream expansion bag 22, the intermediate expansion bag 24, and the downstream expansion bag 26 to atmospheric pressure. The pressure control unit 86 responds to the repeatedly issued blood pressure estimation start command (time point tm1) and repeatedly executes the pressure control cycle for such blood pressure estimation. The aforementioned monitoring pressure PcHm can be the same as, or different from, the first maintenance pressure PcH1 maintained in the first maintenance interval (time point tk2 to time point tk3) or the second maintenance pressure PcH2 maintained in the second maintenance interval (time point tk4 to time point tk5).

[0119] The pulse wave extraction unit 88 extracts a pair of pulse waves MW11 and MW13 obtained by a low-pass filter for pulse wave discrimination that distinguishes signals in the 0Hz to 25Hz band, at a pressure sufficiently lower than the lowest blood pressure value DAP of the living subject 14, for example, within a first maintenance pressure PcH1 of a first maintenance interval preset in the range of 20 to 60 mmHg. This is done from the output signal of the first pressure sensor T1 indicating the compression pressure in the upstream expansion bag 22 and the output signal of the third pressure sensor T3 indicating the compression pressure PcH1 of the downstream expansion bag 26. These pulse waves are stored.

[0120] Furthermore, under the second maintenance pressure PcH2 in the second maintenance interval, which is set to a value lower than the first maintenance pressure PcH1, the pulse wave extraction unit 88 extracts a pair of pulse waves MW21 and MW23 from the output signal of the first pressure sensor T1 indicating the pressure PcH2 in the upstream expansion bag 22 and the output signal of the third pressure sensor T3 indicating the pressure PcH2 in the downstream expansion bag 26, respectively, through the low-pass filter for pulse wave discrimination, and stores them.

[0121] A pair of pulse waves MW11 and MW13, and a pair of pulse waves MW21 and MW23, are pressure vibration waves generated synchronously with pulses superimposed on pressures PcH1 and PcH2. The pulse wave extraction unit 88 stores the pulse waves MW11 and MW13, and MW21 and MW23, in association with the pressure Pc at which those pulse waves were generated. Furthermore, as described above, the pulse waves MW11 and MW13, and MW21 and MW23, are obtained through low-pass filtering of pulse wave acquisition signals in the 0Hz to 25Hz band; therefore, as described later... Figure 16 As shown, the magnitudes of pulse waves MW11 and MW13, as well as pulse waves MW21 and MW23, are expressed in mmHg, the same unit as the compressive pressure Pc.

[0122] The pulse wave propagation velocity calculation unit 90 calculates the time difference (propagation time) Δt113 between a pair of pulse waves MW11 and MW13 and the time difference (propagation time) Δt213 between a pair of pulse waves MW21 and MW23 in multiple intervals within a region where the compression pressure Pc of the compression band 12 is sufficiently lower than the lowest blood pressure value DAP of the living body 14, such as the first maintenance interval (time point tk2 to time point tk3) and the second maintenance interval (time point tk4 to time point tk5). Next, the pulse wave propagation velocity calculation unit 90 calculates the pulse wave propagation velocity PWV1 (=L13 / Δt113) in the first maintenance interval and the pulse wave propagation velocity PWV2 (=L13 / Δt213) in the second maintenance interval based on the time difference Δt113 and Δt213 and the distance L13 between the upstream expansion bag 22 and the downstream expansion bag 26, which is the propagation distance, and stores them.

[0123] Figure 16 This is a diagram that superimposes the amplitude of the pulse wave MW and its first differential waveform dMW / dt on a common time axis at the same time. It shows that the zero-crossing point ZX1 of the pulse wave's first differential waveform dMW / dt from negative to positive is the same time point as the minimum part (local minimum point) MWLMP of the pulse wave MW; the zero-crossing point ZX2 of the pulse wave's first differential waveform dMW / dt from positive to negative is the same time point as the maximum part (maximum peak point, i.e., local maximum point) MWLXP of the pulse wave MW; and the zero-crossing point ZX3 of the pulse wave's first differential waveform dMW / dt from negative to positive is the same time point as the notch part (notch point, i.e., dicrotic notch point) MWLNP of the pulse wave MW after the maximum part MWLXP.

[0124] In order to generate Equation (2) which serves as the inherent relationship for estimating the estimated minimum blood pressure value DAPe, the pulse wave propagation velocity calculation unit 90 calculates the time difference Δt113 between the minimum points of a pair of pulse waves MW11 and MW13. D The time difference Δt213 between the minimum points of a pair of pulse waves MW21 and MW23 DThe time differences Δt113 and Δt213 are used as the minimum points of pulse waves MW11 and MW13, and the minimum points of pulse waves MW21 and MW23. For example, the rising points of pulse waves MW11 and MW13, or the zero-crossing point from negative to positive of the first differential wave of pulse waves MW11 and MW13, and the rising points of pulse waves MW21 and MW23, or the zero-crossing point from negative to positive of the first differential wave of pulse waves MW21 and MW23 are used. Furthermore, the pulse wave propagation velocity calculation unit 90 calculates the pulse wave propagation velocity PWV1 in the first maintenance interval. D (=L13 / Δt113 D ), and the pulse wave propagation velocity PWV2 in the second maintenance interval. D (=L13 / Δt213 D ).

[0125] The pulse wave propagation velocity calculation unit 90 calculates the time difference Δt113S between the maxima of a pair of pulse waves MW11 and MW13, and the time difference Δt213S between the maxima of a pair of pulse waves MW21 and MW23, as the time differences Δt113 and Δt213 used to generate equation (4), which is an inherent relationship for estimating the estimated maximum blood pressure value SAPe. For the maxima of pulse waves MW11 and MW13, and the maxima of pulse waves MW21 and MW23, for example, the maximum peak point of pulse waves MW11 and MW13 or the zero-crossing point of the first differential wave of pulse waves MW11 and MW13 from positive to negative, and the maximum peak point of pulse waves MW21 and MW23 or the zero-crossing point of the first differential wave of pulse waves MW21 and MW23 from positive to negative. The pulse wave propagation velocity calculation unit 90 calculates the pulse wave propagation velocity PWV1S (=L13 / Δt113S) in the first maintenance interval and the pulse wave propagation velocity PWV2S (=L13 / Δt213S) in the second maintenance interval, which are used in the estimation of the estimated maximum blood pressure value SAPe.

[0126] In addition, Figure 16 The diagram illustrates the use of the first differential waveform dMW / dt of the pulse wave MW to determine the minimum region MWLMP, maximum region MWLXP, and notch region MWLNP of the pulse wave MW. However, if... Figure 17 As shown, the pulse wave MW and its second differential waveform d can also be used. 2 MW / dt 2 To find it. Figure 17 The pulse wave MW and its second differential waveform d are represented on a common time axis at the same time phase. 2 MW / dt2 The figure shows the correspondence between the minimum region MWLMP and the notched region MWLNP of the pulse wave MW and the vertices ZT1 and ZT3 of the second differential waveform of the pulse wave MW. Figure 17 In the middle, the second differential waveform d 2 MW / dt 2 The first peak (peak point) within the period ZT1 is the same time point as the minimum point MWLMP, which is the rise time point of the pulse wave MW. In addition, the peak ZT3, which is the maximum point on the second differential waveform after the peak ZT2, is the same time point as the notch point MWLNP, and the peak ZT2 of the second differential waveform is the same time point as the maximum point MWLXP of the pulse wave MW.

[0127] In use Figure 17 In the case of the second differential waveform shown, the pulse wave propagation velocity calculation unit 90 calculates, for example, the time difference Δt113D between the peaks (peaks) ZT1 of the second differential waveforms of a pair of pulse waves MW11 and MW13, and the time difference Δt213D between the peaks (peaks) ZT1 of the second differential waveforms of a pair of pulse waves MW21 and MW23, as the time differences Δt113 and Δt213 used for generating equation (2), and calculates the pulse wave propagation velocity PWV1 in the first maintenance interval. D (=L13 / Δt113 D ), and the pulse wave propagation velocity PWV2 in the second maintenance interval. D (=L13 / Δt213 D Equation (2) is an inherent relationship for estimating the estimated minimum blood pressure value DAPe. The pulse wave propagation velocity calculation unit 90, in the case of generating equation (6), also calculates the time difference Δt113 based on the second differential waveform. DN and Δt213 DN Pulse wave propagation velocity PWV1 DN Pulse wave propagation velocity (PWV2) DN Equation (6) is an inherent relationship for estimating the estimated notch blood pressure value DNAPe.

[0128] After generating the inherent relationship between equations (2) and (4), the pulse wave propagation velocity calculation unit 90 calculates the time difference Δt113 between the minimum points of a pair of pulse waves MW11 and MW13 within the monitoring pressure maintenance interval (time point tm2 to time point tm3) of a certain monitoring pressure PcHm formed according to the blood pressure estimation start command (time point tm1). D And the time difference Δt113 between the maximum parts S Based on those time differences Δt113 D and Δt113S The pulse wave velocity PWV used in estimating the estimated minimum blood pressure value DAPe in equation (2) is calculated respectively. D The pulse wave velocity (PWV) used in the estimation of the estimated highest blood pressure value SAPe in equation (4) S .

[0129] The inherent relation generation unit 92 generates and stores the actual highest blood pressure value SAP for the living subject 14. R Actual lowest blood pressure value (DAP) R The actual compression pressures in the low-pressure range, namely compression pressures PcH1 and PcH2, and the actual pulse wave propagation velocity PWV1 obtained under these compression pressures PcH1 and PcH2. S Pulse wave propagation velocity (PWV2) S Or PWV1 D PWV2 D The inherent relationship between them is shown in equations (2) and (4). This inherent relationship is used repeatedly in subsequent monitoring cycles.

[0130] The inherent relation generation unit 92 substitutes the lowest blood pressure value DAP measured by the blood pressure measurement unit 84 into the two equations represented by equation (1) which expresses the linear relationship. R This is used as the DAP, and the time difference Δt113 between the minimum points of a pair of pulse waves is substituted into it. D and time difference Δt213 D The actual pulse wave propagation speed is used as PWV1. D and PWV2 D When, the i obtained as a solution to the two unknowns i and s of the two equations is respectively D and s D As a measured correction value, an inherent relationship for estimating the lowest blood pressure is generated for the living subject 14, represented by equation (2), wherein the pair of pulse waves are obtained respectively according to multiple pressures (first maintenance pressure of the first maintenance interval) PcH1 and pressures (second maintenance pressure of the second maintenance interval) PcH2 in the low pressure interval that are lower than the lowest blood pressure value DAP of the living subject 14.

[0131] DAPe = PWV D 2 / s D -i D / s D +Pc···(2)

[0132] The inherent relation generation unit 92 substitutes the two equations represented by equation (3) which expresses the linear relationship into the highest blood pressure value SAP measured by the blood pressure measurement unit 84. R The time difference Δt113 between the maxima of a pair of pulse waves was used as the SAP and substituted into the values. S and time difference Δt213 S The actual pulse wave propagation speed is used as PWV1. S and PWV2 S When, the i obtained as a solution to the two unknowns i and s of the two equations is respectively S and s S As a measured correction value, an inherent relationship for estimating the highest blood pressure is generated for the living subject 14, represented by equation (4), wherein the pair of pulse waves are obtained respectively according to multiple compression pressures (first maintenance pressure of the first maintenance interval) PcH1 and compression pressure (second maintenance pressure of the second maintenance interval) PcH2 in the low pressure interval that are lower than the lowest blood pressure value DAP of the living subject 14.

[0133] SAPe = PWV S 2 / s S -i S / s S +Pc···(4)

[0134] The blood pressure estimation unit 94 includes a minimum blood pressure estimation unit 96 and a maximum blood pressure estimation unit 98. After determining the inherent relationship shown in equation (2), the minimum blood pressure estimation unit 96, according to the blood pressure estimation cycle, calculates the actual compression pressure PcH1 in the low-pressure range that is sufficiently lower than the minimum blood pressure value DAP of the living organism 14 and the actual pulse wave velocity PWV1 obtained at that compression pressure PcH1. D Or, the actual compressive pressure PcH2 and the actual pulse wave propagation velocity PWV2 obtained under that compressive pressure PcH2. D Applying the inherent relationship shown in Equation (2), the estimated minimum blood pressure value DAPe for the living subject 14 is thus estimated. Regarding the compression pressure control, only one of the first maintenance interval and the second maintenance interval may be set. Alternatively, the compression pressure PcH1 and pulse wave velocity PWV1 may be estimated by applying the inherent relationship expressed in Equation (2). D The estimated minimum blood pressure value obtained, and the inherent relationship expressed by equation (2) applied to the compression pressure PcH2 and pulse wave velocity PWV2, are used to determine the optimal blood pressure. D The average of the estimated lowest blood pressure values ​​is used as the estimated lowest blood pressure value DAPe.

[0135] After determining the inherent relationship shown in equation (4), the highest blood pressure estimation unit 98, according to the blood pressure estimation cycle, calculates the actual compression pressure PcH1 in the low-pressure range that is sufficiently lower than the lowest blood pressure value DAP of the living organism 14 and the actual pulse wave propagation velocity PWV1 obtained at that compression pressure PcH1. S Or, the actual compressive pressure PcH2 and the actual pulse wave propagation velocity PWV2 obtained under that compressive pressure PcH2. S Applying the inherent relationship shown in Equation (4), the estimated maximum blood pressure value SAPe of the living subject 14 is estimated.

[0136] Figure 18 The lowest blood pressure (DAP) values ​​measured using an intravascular catheter at eight time points in an experimental animal (dog) where blood pressure varied widely due to a drug, were generated. R The relationship between the estimated minimum blood pressure value DAPe estimated by the blood pressure monitoring device of this embodiment and the inherent relation (2) obtained by the minimum blood pressure estimation unit 96 as described above. Figure 18 The horizontal axis represents the estimated lowest blood pressure value (DAPe), and the horizontal axis represents the measured lowest blood pressure value (DAP). R The two-dimensional coordinates of the vertical axis, shown therein, depict the regression line plotted by the 8 points as y = 0.6648x + 32.154, with a coefficient of determination R0. 2 For R 2 =0.95, therefore, the estimated lowest blood pressure value DAPe and the measured lowest blood pressure value DAP were confirmed to be within the range of 0.95. R There is a high correlation between them.

[0137] Figure 19 This is a flowchart explaining the main parts of the control operation of the electronic control device 70. When the blood pressure estimation start operation button 80 is operated to the "on" position, in step S1 (hereinafter "step") corresponding to the compression pressure control unit 86, the compression pressure Pc of the compression band 12 is increased. Specifically, as follows... Figure 6 As shown, with the rapid exhaust valve 52 in the closed state and the air pump 50 in the operating state, the pressure of the compressed air pumped from the air pump 50 is rapidly increased in the main pipe 56 and in the upstream expansion bag 22, intermediate expansion bag 24 and downstream expansion bag 26 connected thereto. Furthermore, the upper arm 16 begins to be compressed by the compression belt 12.

[0138] Next, in S2 corresponding to the pressure control unit 86, based on the output signal of the fourth pressure sensor T4 representing the pressure Pc of the pressure belt 12, it is determined whether the pressure Pc is above the preset target pressure value PCM (e.g., 180 mmHg). Figure 6At a time point before time t2, the judgment of S2 above is negative, and this process is repeated. Figure 19 The processing below S1.

[0139] When the pressure Pc reaches the target pressure value PCM and S2 is confirmed, in S3 corresponding to the pressure control unit 86, the air pump 50 is stopped, and the exhaust control valve 54, the first on / off valve E1, the second on / off valve E2, and the third on / off valve E3 are activated to slowly exhaust the air by sequentially reducing the pressure Pc through the pressure belt 12 in steps of P1, P2, P3, ..., Px, which are preset at 3 to 5 mmHg / sec. While maintaining the aforementioned step pressures P1, P2, P3, ..., Px, the first on / off valve E1, the second on / off valve E2, and the third on / off valve E3 are each set to the closed state. Figure 6 Time t2 is the starting point of the aforementioned slow exhaust. In addition, the period from time t3 to t4 is the time during which the pressure Pc of the pressure belt 12 is maintained at the step pressure P1 for a predetermined time, for example, during the period of generating 2 beats.

[0140] Next, in S4, during the period when the pressures P1, P2, and P3 are maintained for a predetermined time, the output signals from the first pressure sensor T1, the second pressure sensor T2, and the third pressure sensor T3 are subjected to low-pass filtering processing for pulse wave acquisition, for example, the signal in the 0Hz to 25Hz band. As a result, pulse wave signals SM1, SM2, and SM3 representing the pulse waves from the upstream expansion bag 22, the intermediate expansion bag 24, and the downstream expansion bag 26 are extracted. Furthermore, by performing low-pass filtering processing on the output signal from the fourth pressure sensor T4, for example, the band less than a few Hz, the pressure Pc of the compression band 12, which has had its AC component removed, is extracted and stored.

[0141] In step S5, corresponding to the pressure control unit 86, it is determined whether the pressure Pc is below the preset measurement end pressure value PCE (e.g., 60 mmHg). If the determination in S5 is negative, that is, in Figure 6 If the time point before time t11 is negative, the above S5 judgment is negative, and the steps below S3 are repeatedly executed.

[0142] When the judgment in S5 above is affirmative, in S6 and S7 corresponding to the blood pressure measuring unit 84, a pair of compression pressures Pc corresponding to the inflection point of the envelope (envelope), that is, the maximum and minimum points of the first differential waveform of the envelope, are measured respectively, and these are taken as the actual highest blood pressure value SAP of the living subject 14. R and lowest blood pressure value DAP RThe envelope (envelope) is obtained by concatenating the peak values ​​of the pulse wave signals SM2 (intermediate pulse waves) sequentially obtained during the descent of the compression pressure Pc of the compression band 12 from a predetermined target pressure value PCM that is sufficiently higher than the highest blood pressure value SAP. These actual highest blood pressure values ​​SAP R and lowest blood pressure value DAP R The inherent relationships used to generate the blood pressure estimate in the living subject 14, namely Equations (2) and (4), are used.

[0143] Next, in S8 corresponding to the pressure control unit 86, control is performed to temporarily maintain the pressure Pc at a certain first maintenance interval (time point tk2 to time point tk3) of the first maintenance pressure PcH1.

[0144] Next, in S9 corresponding to the pulse wave extraction unit 88, a pair of pulse waves MW11 and MW13 are extracted from the output signal of the first pressure sensor T1 representing the pressure pressure PcH1 in the upstream expansion bag 22 under the first maintenance pressure PcH1 and the output signal of the third pressure sensor T3 representing the pressure pressure PcH1 in the downstream expansion bag 26 under the first maintenance pressure PcH1, respectively, and stored.

[0145] Next, in S10 corresponding to the pulse wave propagation velocity calculation unit 90, the time difference Δt113 between the minimum points of a pair of pulse waves MW11 and MW13 is calculated. D Based on this time difference Δt113 D Calculate the pulse wave propagation velocity PWV1 in the first maintenance interval. D (=L13 / Δt113 D Simultaneously, in S10, the time difference Δt113 between the maxima of a pair of pulse waves MW11 and MW13 is also calculated. S Based on this time difference Δt113 S Calculate the pulse wave propagation velocity PWV1 in the first maintenance interval. S (=L13 / Δt113 S ).

[0146] Then, in S11 corresponding to the pressure control unit 86, control is performed to make the pressure Pc maintain a second maintenance interval (time point tk4 to time point tk5) where the second maintenance pressure Pc is lower than the first maintenance pressure PcH1.

[0147] Next, in S12 corresponding to the pulse wave extraction unit 88, a pair of pulse waves MW21 and MW23 are extracted from the output signal of the first pressure sensor T1 representing the pressure pressure PcH2 in the upstream expansion bag 22 and the output signal of the third pressure sensor T3 representing the pressure pressure PcH2 in the downstream expansion bag 26 under the second maintenance pressure PcH2 using a bandpass filter for pulse wave discrimination, and stored.

[0148] Next, in S13 corresponding to the pulse wave propagation velocity calculation unit 90, the time difference Δt213 between the minimum points of a pair of pulse waves MW21 and MW23 is calculated. D Based on this time difference Δt213 D Calculate the pulse wave propagation velocity PWV2 in the second maintenance interval. D (=L13 / Δt213 D Simultaneously, in S13, the time difference Δt213 between the maxima of a pair of pulse waves MW21 and MW23 is also calculated. S Based on this time difference Δt213 S Calculate the pulse wave propagation velocity PWV2 in the second maintenance interval. S (=L13 / Δt213 S ).

[0149] In S14, corresponding to the inherent relationship generation unit 92, the lowest blood pressure value DAP measured in S6 is substituted into the two equations represented by equation (1) which represents the linear relationship. R This is used as the DAP, and the time difference Δt113 between the minimum points of a pair of pulse waves is substituted into it. D and time difference Δt213 D The actual pulse wave propagation speed is used as PWV1. D and PWV2 D When, the i obtained as a solution to the two unknowns i and s of the two equations is respectively D and s D As a measured correction value, an inherent relationship for estimating the lowest blood pressure is generated for the living body 14 as the subject of the test, represented by equation (2), wherein the pair of pulse waves are obtained respectively according to the first maintenance pressure PcH1 of the first maintenance interval and the second maintenance pressure PcH2 of the second maintenance interval.

[0150] In addition, in S14, the highest blood pressure value SAP measured in S7 was substituted into the two equations represented by equation (3) which expresses the linear relationship. R The time difference Δt113 between the minimum points of a pair of pulse waves was used as the basis for the SAP. Sand time difference Δt213 S The actual pulse wave propagation speed PWV1 S Pulse wave propagation velocity PWV2 S When used as PWV, i is obtained as a solution to the two unknowns i and s of the two equations. S and s S As a measured correction value, an inherent relationship for estimating the highest blood pressure is generated for the living subject 14, represented by equation (4), wherein the pair of pulse waves are obtained according to the first maintenance pressure PcH1 of the first maintenance interval and the second maintenance pressure PcH2 of the second maintenance interval, respectively.

[0151] Next, in S15, the rapid exhaust valve 52 is activated to release the pressure in the upstream expansion bag 22, the intermediate expansion bag 24 and the downstream expansion bag 26 to atmospheric pressure.

[0152] In S16, it is determined whether a blood pressure estimation start command has been issued, which is repeated at a predetermined blood pressure estimation cycle, for example, a cycle of tens of seconds to several minutes. If the determination in S16 is negative, the system enters a standby state; otherwise, if the determination is positive, the blood pressure estimation routine in S17 and below is executed.

[0153] In S17, corresponding to the compression pressure control unit 86, control is performed to increase the compression pressure Pc to a compression pressure, such as the monitoring pressure PcHm, which is 20 to 60 mmHg lower than the lowest blood pressure value DAP of the living body 14, forming a monitoring pressure maintenance interval (time point tm2 to time point tm3) that maintains the monitoring pressure PcHm.

[0154] Next, in S18 corresponding to the pulse wave extraction unit 88, a pair of pulse waves MWm1 and MWm3 are extracted from the output signal of the first pressure sensor T1 representing the pressure pressure PcHm in the upstream expansion bag 22 and the output signal of the third pressure sensor T3 representing the pressure pressure PcHm in the downstream expansion bag 26 under the monitoring pressure PcHm in the monitoring pressure maintenance interval, and stored.

[0155] Next, in S19 corresponding to the pulse wave propagation velocity calculation unit 90, the time difference Δtm13 between the minimum points of a pair of pulse waves MWm1 and MWm3 is calculated. D Based on this time difference Δtm13 D Calculate the pulse wave propagation velocity PWVm within the monitoring pressure maintenance interval. D (=L13 / Δtm13 D Additionally, the time difference Δtm13 between the maxima of a pair of pulse waves MWm1 and MWm3 was calculated.S Based on this time difference Δtm13 S Calculate the pulse wave propagation velocity PWVm within the monitoring pressure maintenance interval. S (=L13 / Δtm13 S ).

[0156] Then, in S20 corresponding to the lowest blood pressure estimation section 96, the monitoring pressure PcHm and pulse wave propagation velocity PWVm are applied to the inherent relationship of the living body 14, which is the subject of the measurement, by applying equation (2) to the monitoring pressure PcHm and pulse wave propagation velocity PWVm. D The estimated lowest blood pressure value DAPe is calculated. Furthermore, in S21 corresponding to the highest blood pressure estimation section 98, the monitoring pressure PcHm and pulse wave velocity PWVm are applied to equation (4) representing the inherent relationship of the living organism 14 being measured. S The estimated highest blood pressure value SAPe was calculated.

[0157] Next, in S22, the estimated minimum blood pressure value DAPe and the estimated maximum blood pressure value SAPe are stored and displayed on the display device 78. Next, in S23, the pressure in the upstream expansion bag 22, the intermediate expansion bag 24, and the downstream expansion bag 26 are each released to atmospheric pressure. Then, in S24, it is determined whether a stop (off) operation has been performed via the blood pressure estimation start operation button 80. While the determination in S24 is negative, the blood pressure estimation routine from S16 onwards is repeated, but when the determination in S24 is positive, the blood pressure monitoring routine ends.

[0158] As described above, the inherent relationship generation unit 92 generates multiple pulse wave propagation velocities (PWV) detected at multiple compression pressures within a low-pressure zone generated by the compression band 12 that is lower than the lowest blood pressure value (DAP) of the living body 14. 2 The regression line shown by the pre-stored linear relationship (Equations (1) and (3)) between the transmural pressure (AP-Pc) of artery 18 and the actual blood pressure value AP of living organism 14 is applied. R (DAP R SAP R ) and the pulse wave velocity PWV1 (PWV1) in the low-pressure zone below the lowest blood pressure value DAP of living organism 14 under the actual compressive pressure PcH1. D PWV1 S ) and the pulse wave propagation velocity PWV2 under actual compression pressure PcH2 (PWV2 D PWV2 S This generates the estimated blood pressure values ​​APe (DAPe, SAPe) and the actual compression pressures PcH1, PcH2, and the actual pulse wave velocity PWV1 (PWV1). D PWV1 S) and pulse wave propagation velocity PWV2 (PWV2 D PWV2 S The inherent relationship between the living body 14 and the actual compression pressure PcHm and the actual pulse wave propagation velocity PWVm (PWVm) is used by the blood pressure estimation unit 94 to estimate the blood pressure by estimating the actual compression pressure PcHm and the actual pulse wave propagation velocity PWVm. D PWVm S The intrinsic relationships (Equation (2) and Equation (4)) are applied to estimate the estimated blood pressure values ​​APe (SAPe, DAPe) of living organism 14.

[0159] As described above, the blood pressure monitoring device 10 according to this embodiment is a blood pressure monitoring device 10 that includes a compression band 12 and repeatedly estimates the estimated blood pressure value (Ape) of a living body 14. The compression band 12 has multiple expansion bags 22, 24, and 26 that are connected in the width direction and form independent air chambers, and is wrapped around the upper arm (compression site) 16 of the living body (subject) 14 to compress the artery 18 of the living body 14. The blood pressure monitoring device 10 includes a linear relationship storage unit 82, which stores the square value (PWV) of the pulse wave propagation velocity detected under multiple compression pressures (Pc) of the compression band 12 in a low-pressure range lower than the lowest blood pressure value (DAP) of the living body 14. 2 A pre-stored linear relationship exists between multiple transmural pressures of artery 18, which are the pressure differences between the blood pressure value AP within artery 18 and the compression pressure Pc of compression band 12; the blood pressure measuring unit 84 measures the actual blood pressure value AP of the living body 14 based on the pulse synchronization wave obtained from artery 18 during the blood pressure reduction process after compression of the upper arm 16 of the living body 14 with a compression pressure Pc higher than the highest blood pressure value SAP of the living body 14. R The inherent relationship generation unit 92, which targets the living organism 14, will generate the actual blood pressure value AP. R The actual blood pressure value AP of the living body 14 is generated by applying multiple actual compression pressures PcH1 and PcH2 in the low-pressure range, as well as actual pulse wave propagation velocities PWV1 and PWV2 obtained based on the propagation time between pulse waves at the actual compression pressures PcH1 and PcH2, to the linear relationship. R The inherent relationship between the actual compression pressures PcH1 and PcH2 and the actual pulse wave velocities PWV1 and PWV2 with respect to the living body 14; and the blood pressure estimation unit 94, which, for the living body 14, applies the actual compression pressure PcHm in the low-pressure range and the actual pulse wave velocities PWVm obtained at the actual compression pressure PcHm to the inherent relationship with respect to the living body 14, thereby estimating the estimated blood pressure value Ape. Thus, in addition to measuring the actual highest blood pressure value SAP of the living body 14 by the blood pressure measuring unit 84, the blood pressure is also estimated. R and the actual lowest blood pressure value DAP RIn addition, the compression pressure Pc generated by the compression band 12 is set to a value lower than the lowest blood pressure value DAP of the living body 14, so that the compression pressure PcHm can be applied in a short time (a few seconds) and blood pressure can be measured at short time intervals. Therefore, the burden on the living body 14 can be reduced, and continuous estimation of blood pressure changes in a shorter time becomes possible.

[0160] Furthermore, in the blood pressure monitoring device 10 according to this embodiment, the actual lowest blood pressure value (DAP) of the living body 14 is used in the inherent relationship generation unit 92. R The actual multiple sustaining pressures (first sustaining pressure PcH1 and second sustaining pressure PcH2) and the time difference Δt113 between the minimum portions of the pulse waves obtained under these actual multiple sustaining pressures. D and Δt213 D The obtained pulse wave propagation velocity (PWV1) D and PWV2 D This generates the estimated minimum blood pressure value DAPe, multiple compression pressures (first maintenance pressure PcH1 and second maintenance pressure PcH2), and pulse wave velocity (PWV1). D and PWV2 D The inherent relationship (2) between the living body 14 and the minimum blood pressure estimation unit 96 is therefore determined by the actual compression pressure (e.g., the first maintenance pressure PcH1) obtained in the low-pressure range below the minimum blood pressure value DAP and the time difference Δt113 between the minimum points of pulse waves obtained at that actual compression pressure. D The obtained pulse wave propagation velocity PWV1 D The intrinsic relation applied to Equation (2) generated by the intrinsic relation generation unit 92 can easily estimate the estimated minimum blood pressure value DAPe of the living body 14.

[0161] Furthermore, according to the blood pressure monitoring device 10 of this embodiment, the time difference (propagation time) Δt113 between the minimum portions of a pair of pulse waves MW11 and MW13 is... D This is the propagation time between the rise points of pulse waves MW11 and MW13. In this way, the time difference Δt113 between the minimum points of a pair of pulse waves MW11 and MW13 can be easily obtained. D The accuracy of blood pressure estimation has been improved.

[0162] Furthermore, according to the blood pressure monitoring device 10 of this embodiment, the blood pressure estimation unit 94 includes a minimum blood pressure estimation unit 96. This minimum blood pressure estimation unit 96, for the living body 14 being measured, calculates multiple actual compression pressures PcH1 or PcH2 in a low-pressure range lower than the minimum blood pressure value DAP of the living body 14, and the actual pulse wave velocity PWV1 obtained at those actual compression pressures PcH1 or PcH2. D Or PWV2 D By applying the inherent relationship of Equation (2) sequentially, the estimated minimum blood pressure value DAPe of the living body 14 is estimated. Thus, the burden on the living body 14 can be reduced, and the estimated minimum blood pressure value DAPe of the living body 14 can be easily estimated.

[0163] Furthermore, in the blood pressure monitoring device 10 according to this embodiment, the actual highest blood pressure value SAP of the living body 14 is used in the inherent relationship generation unit 92. R The actual multiple pressures (first sustaining pressure PcH1 and second sustaining pressure PcH2) and the time difference Δt113 between the maxima of the pulse wave obtained under these actual multiple pressures. S and Δt213 S The obtained pulse wave propagation velocity (PWV1) S and PWV2 S The system generates an intrinsic relationship (4) between the estimated maximum blood pressure value SAPe and the compression pressure and pulse wave propagation velocity in living organism 14. Therefore, the maximum blood pressure estimation unit 98 calculates the actual compression pressure (e.g., the first maintenance pressure PcH1) obtained in the low-pressure range below the minimum blood pressure value DAP and the time difference Δt113 between the maximum points of pulse waves obtained at that actual compression pressure. S The obtained pulse wave propagation velocity PWV1 S When applied to formula (4) generated by the inherent relation generation unit 92, the estimated maximum blood pressure value SAPe of the living organism 14 can be estimated.

[0164] Furthermore, according to the blood pressure monitoring device 10 of this embodiment, the time difference (propagation time) Δt113 between the maximum portions of a pair of pulse waves MW11 and MW13 is... S This is the propagation time between the maxima of pulse wave MW11 and pulse wave MW13. This allows for easy acquisition of the propagation time between the maxima of the pulse waves, improving the accuracy of blood pressure estimation.

[0165] Furthermore, according to the blood pressure monitoring device 10 of this embodiment, the blood pressure estimation unit 94 includes a maximum blood pressure estimation unit 98. This maximum blood pressure estimation unit 98, for the living subject 14, calculates the actual compression pressure PcH1 or PcH2 in the low-pressure range that is lower than the lowest blood pressure value DAP of the living subject 14, and the actual pulse wave velocity PWV1 obtained at those actual compression pressures PcH1 or PcH2. S Or PWV2 S By applying the inherent relationship of Equation (4) sequentially, the estimated maximum blood pressure value SAPe of the living organism 14 can be estimated. Thus, the burden on the living organism 14 can be reduced, and the estimated maximum blood pressure value SAPe of the living organism 14 can be easily estimated.

[0166] Furthermore, the blood pressure monitoring device 10 according to this embodiment includes: a compression pressure control unit 86, which causes multiple compression pressures (first maintenance pressure PcH1 and second maintenance pressure PcH2) in a low-pressure range lower than the lowest blood pressure value DAP of the living body 14 to be reduced in stages, so as to form multiple intervals (first maintenance interval and second maintenance interval) that are temporarily maintained at a certain value in the low-pressure range lower than the lowest blood pressure value DAP of the living body 14; a pulse wave extraction unit 88, which extracts pulse waves as pressure vibrations generated synchronously with the pulse in multiple expansion bags (upstream expansion bag 22 and downstream expansion bag 26) under the compression pressure in the multiple intervals; and a pulse wave propagation velocity calculation unit 90, which calculates the pulse wave propagation velocity based on the time difference of the pulse waves obtained in the multiple intervals and the distance (L13) between the multiple expansion bags. Therefore, the pulse waves obtained in the intervals where the pressure is maintained at a certain value (the first maintenance interval and the second maintenance interval) are waveforms that are not distorted due to the influence of pressure changes. Thus, the pulse wave propagation velocity PWV can be accurately obtained, and the inherent relational formulas (2) and (4) of the living body 14 can be accurately calculated.

[0167] Furthermore, according to the blood pressure monitoring device 10 of this embodiment, the compression band 12 is wrapped around the compressed portion of the living body and has independent upstream expansion bags 22, intermediate expansion bags 24, and downstream expansion bags 26 connected in the width direction to respectively compress the compressed portion of the living body 14. The upstream expansion bags 22, intermediate expansion bags 24, and downstream expansion bags 26 respectively compress the artery 18 in the compressed portion with the same compression pressure. Thus, it has the advantage of being able to simultaneously perform blood pressure measurement using compression of the limbs of the living body 14 and pulse wave velocity (PWV) detection.

[0168] Example 2

[0169] Next, a blood pressure monitoring device 110 according to another embodiment of the present invention will be described. In the following, the parts that are common to the foregoing embodiments are marked with the same reference numerals and are omitted from the description.

[0170] In the aforementioned embodiment, in order to estimate the estimated maximum blood pressure value SAPe of the living organism 14, the actual maximum blood pressure value SAP of the living organism 14 is used in the inherent relationship generation unit 92. R The actual multiple pressures (first sustaining pressure PcH1 and second sustaining pressure PcH2) and the time difference Δt113 between the maxima of the pulse wave obtained under these actual multiple pressures. S and Δt213 S The obtained pulse wave propagation velocity (PWV1) S and PWV2 S ), generating the intrinsic relationship (4) between the estimated highest blood pressure value SAPe and the compression pressure and pulse wave propagation velocity of the subject, in the highest blood pressure estimation section 98, the actual compression pressure (e.g., the first maintenance pressure PcH1) obtained in the low-pressure range lower than the lowest blood pressure value DAP and the time difference Δt113 between the maximum portion of the pulse wave obtained at that actual compression pressure. S The obtained pulse wave propagation velocity PWV1 S Applying formula (4) generated by the inherent relation generation unit 92, the estimated maximum blood pressure value SAPe of the living organism 14 is estimated. In contrast, in this embodiment, the difference is that the estimated notch blood pressure value DNAPe is estimated using the same estimation method as described above, and the estimated maximum blood pressure value SAPe is estimated based on the estimated notch blood pressure value DNAPe, which is the blood pressure at the notch site that is locally formed after the maximum site.

[0171] Figure 20 This is a functional block diagram illustrating the control function of the electronic control device 170 in this embodiment. Similar to the linear relationship storage unit 82, the linear relationship storage unit 182 detects the squared values ​​of multiple pulse wave propagation velocities PWV under multiple compression pressures Pc of the compression band 12 in a low-pressure range lower than the lowest blood pressure value DAP of the living organism 14. 2In addition to the stored linear relationships of equations (1) and (3) with respect to the transmural pressure (AP-Pc) of artery 18, a regression line is stored as a linear relationship represented by equation (5) with respect to the notched blood pressure value DNAP, where the transmural pressure is the pressure difference between the blood pressure value AP and the compression pressure Pc within artery 18. The regression line represented by equation (5) is derived from Bramwell Hill's equation (7) via equations (8) to (14) in the same manner as in the aforementioned Example 1. The pulse wave propagation velocity PWV in equation (5) is calculated based on the time difference Δt between the positions of the notched portions MWLNP of a pair of pulse waves obtained from the upstream expansion bag 22 and the downstream expansion bag 26, respectively, within a pressure region lower than the lowest blood pressure value DAP of the living organism 14, during a certain pressure period. As described above... Figure 16 , Figure 17 As shown, the position of the notch region MWLNP is determined based on the first differential waveform of the pulse wave MW and the second differential waveform of the pulse wave MW.

[0172] PWV 2 =s·(DNAP-Pc)+i···(5)

[0173] Where s represents the slope of the regression line and i represents the intercept of the regression line.

[0174] Figure 21 It involves combining two-dimensional coordinate data with the regression line y and the coefficient of determination R. 2 The graph, presented together, shows the results of Experiment No. 9 conducted by the inventors regarding the relationship between transwall pressure and pulse wave propagation velocity in a predetermined living organism. The coefficient of determination R in this result... 2 The value is 0.9779, which is close to 1. Therefore, it is a high-quality regression line representing a linear relationship.

[0175] Similar to the blood pressure measuring unit 84, before the inherent relation of equation (6) described later is generated by the inherent relation generation unit 192, the blood pressure measuring unit 184 uses a blood pressure measuring device to measure the actual lowest blood pressure value DAP of the living body 14 being measured. R In addition, the blood pressure measurement unit 184 uses a blood pressure measuring device to measure the average blood pressure value MAP of the living subject 14, and determines the measured average blood pressure value MAP as the actual notched blood pressure value DNAP of the living subject 14. RThe aforementioned mean blood pressure value MAP represents the compression pressure Pc at the maximum amplitude of the pulse wave. For example, in an oscilloscope-based automatic blood pressure measuring device, the compression pressure Pc at the time point representing the maximum value (maximum peak value) of the envelope (notch) is measured as the mean blood pressure value MAP. The envelope (notch) is obtained by concatenating the peak values ​​of the pulse wave signals SM2 (intermediate pulse waves) obtained sequentially during the descent of the compression pressure Pc of the compression band 12 from a pre-set target pressure value PCM that is sufficiently higher than the highest blood pressure value SAP. The mean blood pressure value MAP measured in this way is approximately equal to the notched blood pressure value DNAP of the living organism 14. Figure 22 The results of experiments conducted by the inventors show the correlation between notched blood pressure values ​​(DNAP) measured directly using a catheter in animals (dogs) and measured average blood pressure values ​​(MAP).

[0176] Similar to the pressure control unit 86, the pressure control unit 186 is as follows: Figure 6 As shown in the time interval t1 to t11, compression pressure control for blood pressure measurement is performed. Then, in order to generate the inherent relationship of equation (6), compression pressure control is performed in the interval between time points tk1 and tk5. Furthermore, in order to estimate the estimated maximum blood pressure value SAPe based on the estimated notch blood pressure value DNAPe and the estimated minimum blood pressure value DAPe of the living organism 14, the blood pressure measurement unit 184 responds to the blood pressure estimation start command (time point tm1) that is repeated at a predetermined blood pressure estimation cycle, and controls the compression pressure Pc to form Figure 6 The monitoring pressure PcHm is a certain monitoring pressure maintained within the monitoring pressure maintenance interval from time point tm1 to time point tm3.

[0177] Similar to the pulse wave extraction unit 88, the pulse wave extraction unit 188 extracts a pair of pulse waves MW11 and MW13 from pulse wave signals SM1 and SM3 obtained by a low-pass filter for pulse wave discrimination that distinguishes signals in the 0Hz to 25Hz band, within a pressure range that is sufficiently lower than the lowest blood pressure value DAP of the living subject 14, for example, 20 to 60 mmHg. This is based on the output signal from the first pressure sensor T1 indicating the compression pressure PcH1 in the upstream expansion bag 22 and the output signal from the third pressure sensor T3 indicating the compression pressure PcH1 in the downstream expansion bag 26, and stores them. Alternatively, the pulse wave extraction unit 188, at a second maintenance pressure PcH2 in a second maintenance interval set to a value lower than the first maintenance pressure PcH1, extracts a pair of pulse waves MW21 and MW23 from a pair of upstream expansion bags 22 and downstream expansion bags 26 respectively, based on the output signal from the first pressure sensor T1 indicating the pressure PcH2 in the upstream expansion bag 22 and the output signal from the third pressure sensor T3 indicating the pressure PcH2 in the downstream expansion bag 26, using a low-pass filter for pulse wave discrimination that distinguishes signals in the band less than 25Hz, and stores them.

[0178] Similar to the pulse wave propagation velocity calculation unit 90, in order to generate the inherent relationship between the minimum blood pressure value DAP in the predetermined living body 14 and the pulse wave propagation velocity according to Equation (2), the pulse wave propagation velocity calculation unit 190 calculates the time difference Δt113 between the minimum points of a pair of pulse waves MW11 and MW13 extracted in the first maintenance interval (time point tk2 to time point tk3). D Calculate the pulse wave propagation velocity PWV1 in the first maintenance interval. D (=L13 / Δt113 D Furthermore, the time difference Δt213 between the minimum points of a pair of pulse waves MW21 and MW23 extracted during the second maintenance interval (time point tk4 to time point tk5) is calculated. D Calculate the pulse wave propagation velocity PWV2 in the second maintenance interval. D (=L13 / Δt213 D ), and store it.

[0179] In addition, in order to generate the inherent relationship between the notched blood pressure value DNAP and the pulse wave propagation velocity PWV in the predetermined living organism 14 according to Equation (6), the pulse wave propagation velocity calculation unit 190 calculates the time difference Δt113 between the notched portions of a pair of pulse waves MW11 and MW13 extracted in the first maintenance interval (time point tk2 to time point tk3). DN Calculate the pulse wave propagation velocity PWV1 in the first maintenance interval.DN (=L13 / Δt113 DN Furthermore, the time difference Δt213 between the notch portions of a pair of pulse waves MW21 and MW23 extracted during the second maintenance interval (time point tk4 to time point tk5) is calculated. DN Calculate the pulse wave propagation velocity PWV2 in the second maintenance interval. DN (=L13 / Δt213 DN ), and store it.

[0180] After generating the inherent relationship between equations (2) and (6), the pulse wave propagation velocity calculation unit 190 calculates the pulse wave propagation velocity within the monitoring pressure maintenance interval (time point tm2 to time point tm3) of a certain monitoring pressure PcHm formed according to the blood pressure estimation start command (time point tm1), based on the time difference Δt113 between the minimum points of a pair of pulse waves MW11 and MW13. D The time difference Δt113 between the notch and the notch region DN To calculate, the pulse wave velocity PWV used in the estimation of the estimated minimum blood pressure value DAPe using equation (2) is calculated respectively. D And the pulse wave velocity PWV used in the estimation of the estimated notched blood pressure value DNAPe using (6) DN And store it.

[0181] Similar to the inherent relationship generation unit 92 in Embodiment 1 described above, the inherent relationship generation unit 192 generates and stores the actual minimum blood pressure value (DAP) for each living body 14 as the subject of the measurement. R The actual compression pressures in the low-pressure range, namely compression pressures PcH1 and PcH2, and the actual pulse wave propagation velocity PWV1 obtained under these compression pressures PcH1 and PcH2. D PWV2 D The inherent relationship between them is shown in equation (2). Furthermore, the inherent relationship generation unit 192 generates and stores the actual notch blood pressure value DNAP. R The actual compression pressures in the low-pressure range, namely compression pressures PcH1 and PcH2, and the actual pulse wave propagation velocity PWV1 obtained under these compression pressures PcH1 and PcH2. DN PWV2 DN The inherent relationship between them is shown in equation (6).

[0182] DNAPe = PWV DN 2 / s DN -i DN / s DN +Pc···(6)

[0183] The inherent relation generation unit 192 substitutes the notched blood pressure values ​​(DNAP) measured by the blood pressure measurement unit 184 into the two equations represented by equation (5) which represent linear relations. R The DNAP was used as a reference, and the time difference Δt113 between the notches of a pair of pulse waves was substituted into it. DN and time difference Δt213 DN The actual pulse wave propagation speed is used as PWV1. DN and PWV2 DN When, the i obtained as a solution to the two unknowns i and s of the two equations is respectively DN and s DN As a measured correction value, an inherent relationship for estimating notched blood pressure is generated for the living subject 14, represented by equation (6), wherein the pair of pulse waves are obtained respectively according to multiple compression pressures (first maintenance pressure of the first maintenance interval) PcH1 and compression pressure (second maintenance pressure of the second maintenance interval) PcH2 in the low pressure interval that are lower than the lowest blood pressure value DAP of the living subject 14.

[0184] The blood pressure estimation unit 194 includes a minimum blood pressure estimation unit 196, a notch blood pressure estimation unit 200, and a maximum blood pressure estimation unit 198. After determining the inherent relationship shown in equation (2), the minimum blood pressure estimation unit 196, according to the blood pressure estimation cycle, calculates the actual compression pressure PcH1 in the low-pressure range that is sufficiently lower than the minimum blood pressure value DAP of the living organism 14 and the actual pulse wave velocity PWV1 obtained at that compression pressure PcH1. D Or, the actual compressive pressure PcH2 and the actual pulse wave propagation velocity PWV2 obtained under that compressive pressure PcH2. D Applying the inherent relationship shown in Equation (2), the estimated minimum blood pressure value DAPe of the living subject 14 is thus estimated.

[0185] After determining the inherent relationship shown in equation (6), the notch blood pressure estimation unit 200, according to the blood pressure estimation cycle, calculates the actual compression pressure PcH1 in the low-pressure range that is sufficiently lower than the lowest blood pressure value DAP of the living organism 14 and the actual pulse wave velocity PWV1 obtained at that compression pressure PcH1. DN Or, the actual compressive pressure PcH2 and the actual pulse wave propagation velocity PWV2 obtained under that compressive pressure PcH2. DN Applying the inherent relationship shown in Equation (6), the estimated notch blood pressure value DNAPe of the living subject 14 is thus estimated.

[0186] The highest blood pressure estimation section 198 states that because the pulse wave MW obtained at a pressure lower than the lowest blood pressure value DAP in living subjects, such as the monitoring pressure PcHm, has the same unit (mmHg) as the pressure Pc, therefore, as Figure 23 As shown, based on the correspondence between the minimum portion of the pulse wave MW and the lowest blood pressure value DAP, the maximum portion and the highest blood pressure value SAP, and the notch portion and the notch blood pressure value DNAP, a pressure is generated. This is based on the estimated lowest blood pressure value DAPe estimated by the lowest blood pressure estimation unit 196, the estimated notch blood pressure value DNAPe estimated in the notch blood pressure estimation unit 200, the pressure Pc of the minimum portion of the actual pulse wave MW of the living subject 14, and the pressure Pc of the notch portion. Figure 24 The relationship shown.

[0187] Furthermore, the highest presumed hypertension section 198 is based on Figure 24 The relationship shown is based on the compression pressure (clamp pressure) Pc, which represents the magnitude of the maximum portion of the actual pulse wave MW obtained from the living body 14, which is the subject of the measurement, at the monitoring pressure PcHm, to estimate the estimated maximum blood pressure value SAPe. Figure 24 The estimated maximum blood pressure (SAPe) is shown to be 115 mmHg, assuming the maximum pulse wave (MW) size is 55.2 mmHg. Furthermore, in... Figure 24 In this study, after assuming a linear relationship between the estimated lowest blood pressure value DAPe, the estimated notch blood pressure value DNAPe, and the corresponding compression pressure Pc, the estimated highest blood pressure value SAPe is estimated. However, a non-linear relationship, such as an exponential function, can also be assumed.

[0188] Figure 25 This is a flowchart describing the main parts of the control operation of the electronic control device 170 in this embodiment. In the following, it will be referred to as... Figure 19 The explanation will focus on the differences.

[0189] S31~S36 and Figure 19 S1 to S6 are the same. The notched blood pressure value (DNAP) is measured in S37, which corresponds to the blood pressure measuring unit 184. R For example, in an oscillometric automatic blood pressure measuring device, the compression pressure Pc at the time point representing the maximum value (peak value) of the envelope (envelope) is measured as the average blood pressure value MAP. The envelope (envelope) is obtained by connecting the peak values ​​of the pulse wave signal SM2 (intermediate pulse wave) obtained sequentially during the process of decreasing the compression pressure Pc of the compression band 12 from a preset target pressure value PCM that is sufficiently higher than the highest blood pressure value SAP.

[0190] Next, in S38 corresponding to the pressure control unit 186, and with Figure 19 Similarly, in S8, the first sustaining pressure PcH1 is maintained, and in S39 corresponding to the pulse wave extraction unit 188, it is... Figure 19 Similarly, S9 extracts the pulse wave under the first sustaining pressure PcH1.

[0191] In S40, corresponding to the pulse wave propagation velocity calculation unit 190, the pulse wave propagation velocity PWV1 under the first sustaining pressure PcH1 is calculated. D Pulse wave propagation velocity PWV1 DN Pulse wave propagation velocity PWV1 D The relationship between Equation (2) used to generate the lowest blood pressure value DAP in the predetermined living body 14 and the pulse wave propagation velocity PWV is based on the time difference Δt113 between the minimum points of a pair of pulse waves MW11 and MW13 extracted in the first maintenance interval (time point tk2 to time point tk3). D The calculated pulse wave propagation velocity PWV1 in the first maintenance interval D (=L13 / Δt113 D Pulse wave propagation velocity PWV1 DN It is used to generate the inherent relation (6) for the living organism 14 that is the subject of the measurement, and is based on the time difference Δt113 between the notch regions of a pair of pulse waves MW11 and MW13 extracted at the first maintenance pressure PcH1. DN The calculated pulse wave propagation velocity PWV1 in the first maintenance interval DN (=L13 / Δt113 DN ).

[0192] Next, in S41 corresponding to the pressure control unit 186, and with Figure 19 Similarly, in S11, the second sustaining pressure PcH2 is maintained, and in S42 corresponding to the pulse wave extraction unit 188, it is similar to... Figure 19 Similarly, S12 extracts the pulse wave under the second sustaining pressure PcH2.

[0193] In S43, corresponding to the pulse wave propagation velocity calculation unit 190, the pulse wave propagation velocity PWV2 under the second sustaining pressure PcH2 is calculated. D Pulse wave propagation velocity PWV2 DN Pulse wave propagation velocity (PWV2) D The relationship between Equation (2) used to generate the lowest blood pressure value DAP in the predetermined living body 14 and the pulse wave propagation velocity PWV is based on the time difference Δt213 between the minimum points of a pair of pulse waves MW21 and MW23 extracted in the second maintenance interval (time point tk4 to time point tk5). DThe calculated pulse wave propagation velocity PWV2 in the second maintenance interval D (=L13 / Δt213 D Pulse wave propagation velocity (PWV2) DN It is used to generate the inherent relation (6) for the living organism 14 that is the subject of the measurement, and is based on the time difference Δt213 between the notch regions of a pair of pulse waves MW21 and MW23 extracted at the second maintenance pressure PcH2. DN The calculated pulse wave propagation velocity PWV2 in the second maintenance interval DN (=L13 / Δt213 DN ).

[0194] In S44, which corresponds to the inherent relationship generation unit 192, the lowest blood pressure value DAP measured in S36 is substituted into the two equations represented by equation (1) which represents the linear relationship. R And respectively, the time difference Δt113 between the minimum parts of a pair of pulse waves was substituted. D and time difference Δt213 D The actual pulse wave propagation speed PWV1 D and PWV2 D When, the i obtained as a solution to the two unknowns i and s of the two equations is respectively D and s D As a measured correction value, an inherent relationship for estimating the lowest blood pressure is generated for the living body 14 as the subject of the test, represented by equation (2), wherein the pair of pulse waves are obtained respectively according to the first maintenance pressure PcH1 of the first maintenance interval and the second maintenance pressure PcH2 of the second maintenance interval.

[0195] In addition, in S44, the notched blood pressure values ​​(DNAP) measured in S37 were substituted into the two equations represented by equation (5) which expresses a linear relationship. R And respectively, the time difference Δt113 between the notch regions of a pair of pulse waves was substituted. DN and time difference Δt213 DN The actual pulse wave propagation speed PWV1 DN and PWV2 DN When, the i obtained as a solution to the two unknowns i and s of the two equations is respectively DN and s DN As a measured correction value, an inherent relationship for estimating notch blood pressure is generated for the living subject 14, represented by equation (6), wherein the pair of pulse waves are obtained according to the first maintenance pressure PcH1 of the first maintenance interval and the second maintenance pressure PcH2 of the second maintenance interval, respectively.

[0196] Next, in S45, similarly to S15, the rapid exhaust valve 52 is activated to release the pressure in the upstream expansion bag 22, the intermediate expansion bag 24 and the downstream expansion bag 26 to atmospheric pressure.

[0197] In S46 to S48, with Figure 19 Similarly, in S16 to S18, when a blood pressure estimation start command is issued, control is performed to increase the compression pressure Pc to a pressure between 20 and 60 mmHg lower than the lowest blood pressure value DAP of the living body 14, such as the monitoring pressure PcHm, forming a monitoring pressure maintenance interval (time point tm2 to time point tm3) that maintains the monitoring pressure PcHm. Through a bandpass filter for pulse wave discrimination, a pair of pulse waves MWm1 and MWm3 are extracted from the output signal of the first pressure sensor T1 representing the compression pressure PcHm in the upstream expansion bag 22 and the output signal of the third pressure sensor T3 representing the compression pressure PcHm in the downstream expansion bag 26, respectively, at the monitoring pressure PcHm in the monitoring pressure maintenance interval.

[0198] Next, in S49 corresponding to the pulse wave propagation velocity calculation unit 190, the time difference Δtm13 between the minimum points of a pair of pulse waves MWm1 and MWm3 is calculated. D Based on this time difference Δtm13 D Calculate the pulse wave propagation velocity PWVm within the monitoring pressure maintenance interval. D (=L13 / Δtm13 D Additionally, the time difference Δtm13 between the notch regions of a pair of pulse waves MWm1 and MWm3 was calculated. DN Based on this time difference Δtm13 DN Calculate the pulse wave propagation velocity PWVm within the monitoring pressure maintenance interval. DN (=L13 / Δtm13 DN ).

[0199] Next, in S50 corresponding to the lowest blood pressure estimation section 196, the monitoring pressure PcHm and pulse wave propagation velocity PWVm are applied to the inherent relationship of the living body 14, which is the subject of measurement, by formula (2). D Thus, the estimated minimum blood pressure value DAPe is calculated. Furthermore, in S51 corresponding to the notch blood pressure estimation section 200, the monitoring pressure PcHm and pulse wave velocity PWVm are applied to equation (6) representing the inherent relationship of the living body 14 being measured. DN This allows for the calculation of the estimated notch blood pressure value, DNAPe.

[0200] Furthermore, in S52 corresponding to the highest blood pressure estimation section 198, based on the estimated lowest blood pressure value DAPe estimated by S50, the estimated notched blood pressure value DNAPe estimated by S51, and the compression pressure Pc of the minimum and notched portions of the actual pulse wave MW of the living subject 14, a pressure is generated. Figure 24 The relationship shown. Next, in S52, according to... Figure 24 The relationship shown is based on the compression pressure Pc, which represents the magnitude of the maximum portion of the actual pulse wave MW obtained from the living body 14, the subject of the measurement, at the monitoring pressure PcHm, to estimate the estimated maximum blood pressure value SAPe. Furthermore, in Figure 24 The estimation is made by assuming a linear relationship, but it can also be made by assuming a nonlinear relationship such as an exponential function.

[0201] In S53 to S55, with Figure 19 Similarly, in S22 to S24, the estimated minimum blood pressure value DAPe and the estimated maximum blood pressure value SAPe are stored and displayed on the display device 78. During the period when the stop (off) operation achieved by the blood pressure estimation start operation button 80 is negative, the blood pressure estimation routine from S46 onwards is repeatedly performed, but when the stop (off) operation achieved by the blood pressure estimation start operation button 80 is positive, the blood pressure monitoring routine is terminated.

[0202] As described above, in the inherent relationship generation unit 192 of the electronic control device 170 according to this embodiment, the actual notch blood pressure value DNAP of the living body 14 that is being measured is used. R The first sustaining pressure PcH1 and the second sustaining pressure PcH2, which are the actual compressive pressures, and the time difference Δt113 between the notch portions of the pulse waves obtained under the first sustaining pressure PcH1 and the second sustaining pressure PcH2, which are the actual compressive pressures, respectively. DN and time difference Δt213 DN The obtained pulse wave propagation velocity PWV1 DN and PWV2 DN The inherent relationship (6) between the estimated notched blood pressure value DNAPe and the compression pressure and pulse wave propagation velocity of the living organism 14 is generated. Therefore, the blood pressure estimation unit 194 obtains the actual monitoring pressure PcHm obtained in a low-pressure range lower than the lowest blood pressure value DAP of the living organism 14 and the pulse wave propagation velocity PWV obtained based on the time difference between the notched portions of the pulse waves obtained at the actual monitoring pressure PcHm. DN The intrinsic relation (6) of the living organism generated by the intrinsic relation generation unit 192 can be applied to easily estimate the estimated notch blood pressure value DNAPe of the living organism 14.

[0203] Furthermore, according to the electronic control device 170 of this embodiment, the propagation time (time difference Δt113) between the notch portions of a pair of pulse waves obtained respectively according to the plurality of first sustaining pressures PcH1 and second sustaining pressures PcH2 is also considered. DN and time difference Δt213 DN The propagation time between the zero-crossing points from negative to positive in the first differential waveform of the pulse wave is given. This allows for easy acquisition of the propagation time between the notch portions of a pair of pulse waves, improving the estimation accuracy of the notch blood pressure value DNAPe.

[0204] Furthermore, according to the electronic control device 170 of this embodiment, the blood pressure estimation unit 194 includes the actual monitoring pressure PcHm in the low-pressure range that is lower than the lowest blood pressure value DAP of the living subject 14, and the actual pulse wave velocity PWVm obtained at the monitoring pressure PcHm. DN The notch blood pressure estimation section 200 of the living body 14 is used to estimate the notch blood pressure value DNAPe by applying the inherent relationship of Equation (6) one by one. Therefore, the notch blood pressure value DNAPe of the living body 14 can be easily estimated.

[0205] Furthermore, according to the electronic control device 170 of this embodiment, the blood pressure estimation unit 194 includes a minimum blood pressure estimation unit 196 and a maximum blood pressure estimation unit 198. The minimum blood pressure estimation unit 196 estimates the blood pressure by measuring the actual monitoring pressure PcHm in the low-pressure range that is lower than the minimum blood pressure value DAP of the living subject 14 and the actual pulse wave velocity PWVm obtained at the monitoring pressure PcHm. D By successively applying the inherent relationship of Equation (2), the estimated minimum blood pressure value DAPe of the living organism 14 is estimated. The maximum blood pressure estimation unit 198 generates the relationship between the pulse wave size in the monitoring pressure PcHm interval lower than the minimum blood pressure value DAP and the estimated blood pressure value Ape based on the estimated minimum blood pressure value DAPe estimated by the minimum blood pressure estimation unit 196 and the estimated notched blood pressure value DNAPe estimated by the notched blood pressure estimation unit 200. Figure 24 By applying this relationship to the maximum values ​​of actual pulse waves obtained successively under the monitoring pressure PcHm, the estimated maximum blood pressure value SAPe can be estimated. Thus, even without accurately determining the time difference between the maxima of a pair of pulse waves obtained successively under the monitoring pressure PcHm, the estimated maximum blood pressure value SAPe of the subject can be easily estimated.

[0206] The present invention has been described in detail above with reference to the accompanying drawings, but the present invention is not limited to this embodiment and can be implemented by other technical solutions.

[0207] For example, in the aforementioned blood pressure monitoring device 10, both the estimated maximum blood pressure value SAPe and the estimated minimum blood pressure value DAPe are estimated. However, it can also be configured to estimate only one of the estimated maximum blood pressure value SAPe and the estimated minimum blood pressure value DAPe. In this case, for example, one of the regression lines of equations (1) and (3) stored in the linear relationship storage unit 82 is not required, nor is one of the minimum blood pressure estimation unit 96 and the maximum blood pressure estimation unit 98 required.

[0208] Alternatively, in the aforementioned embodiments, multiple pulse waves can be extracted according to the first maintenance interval of the first maintenance pressure PcH1, the second maintenance interval of the second maintenance pressure PcH2, and the monitoring pressure maintenance interval of the monitoring pressure PcHm, and the average value of the time difference collected from those multiple pulse waves can be used.

[0209] In addition, in Embodiments 1 and 2, the compression belt 12 has three expansion bags, namely the upstream expansion bag 22, the middle expansion bag 24 and the downstream expansion bag 26, but having at least two expansion bags is sufficient.

[0210] In addition, step-by-step pressure reduction was used for the compression band 12 in Examples 1 and 2, but it can also be a continuous slow pressure reduction.

[0211] Furthermore, the above is merely one implementation method. Although not all other embodiments are illustrated herein, the present invention can be implemented without departing from its spirit by making various changes and improvements based on the knowledge of those skilled in the art.

[0212] Label Explanation

[0213] 10, 110: Blood pressure monitoring device

[0214] 12: Compression band

[0215] 14: Live subject (subject to testing)

[0216] 16: Upper arm (the area being compressed)

[0217] 18: Artery

[0218] 22: Upstream side expansion bag (expansion bag)

[0219] 24: Intermediate expansion bag (expansion bag)

[0220] 26: Downstream expansion bag (expansion bag)

[0221] 82, 182: Linear Relational Storage Department

[0222] 84, 184: Blood Pressure Measurement Department

[0223] 86, 186: Pressure control unit

[0224] 88, 188: Pulse wave extraction section

[0225] 90, 190: Calculation of pulse wave propagation velocity

[0226] 92, 192: Inherent Relation Generation Department

[0227] 94, 194: Blood Pressure Estimation Section

[0228] 96, 196: Estimated lowest blood pressure (estimated blood pressure)

[0229] 98, 198: Estimated highest blood pressure (estimated blood pressure)

[0230] 200: Presumed Blood Pressure at the Notch

Claims

1. A blood pressure monitoring device (10; 110) comprising a compression band (12) having a plurality of expansion pockets (22, 24, 26) connected in the width direction to form independent air chambers, and wrapped around a compression site (16) of a subject (14) to compress the artery (18) of the subject, the blood pressure monitoring device repeatedly estimating an estimated blood pressure value of the subject, the blood pressure monitoring device being characterized in that it comprises: Linear relational storage unit (82; 182), which stores a pre-stored linear relationship between the square of the pulse wave propagation velocity detected at multiple compression pressures of the compression band in a low-pressure range lower than the lowest blood pressure value of a living organism and multiple transmural pressures of the artery, wherein the transmural pressure is the pressure difference between the blood pressure value in the artery and the compression pressure of the compression band; The blood pressure measuring unit (84; 184) measures the actual blood pressure value of the subject based on the pulse synchronization wave from the artery obtained during the blood pressure reduction process after the compression site of the subject is compressed with a pressure higher than the subject's highest blood pressure value. The inherent relationship generation unit (92; 192) applies the actual blood pressure value, the actual compression pressure in the low-pressure range, and the actual pulse wave propagation velocity obtained based on the propagation time between pulse waves obtained at the actual compression pressure to the linear relationship for the subject, thereby generating an inherent relationship between the actual blood pressure value, the actual compression pressure, and the actual pulse wave propagation velocity of the subject with respect to the subject. as well as The blood pressure estimation unit (94; 194) estimates the estimated blood pressure value by applying the actual compression pressure in the low-pressure range and the actual pulse wave propagation velocity obtained at the actual compression pressure to the subject, thereby estimating the estimated blood pressure value.

2. The blood pressure monitoring device (10; 110) according to claim 1, characterized in that, The estimated blood pressure value estimated by the blood pressure estimation unit (94; 194) is the estimated lowest blood pressure value DAPe of the subject (14). When the pulse wave propagation velocity of a living organism is set as PWV, the lowest blood pressure value of a living organism is set as DAP, and the compression pressure of a living organism is set as Pc, the linear relationship is represented by the regression line expressed by the following equation (1). Where s represents the slope of the regression line and i represents the intercept of the regression line.

3. The blood pressure monitoring device (10; 110) according to claim 2, characterized in that, When i D and s D When used as a measured correction value, the inherent relationship of the measured object (14) is represented by the following equation (2), where i D and s D The actual pulse wave propagation velocity (PWV) is obtained by substituting the lowest blood pressure value measured for the subject into the two equations represented by equation (1), respectively, as DAP, the different actual compression pressures within the low-pressure range, respectively, as Pc, and the propagation time between the minimum parts of the pulse wave obtained according to the different actual compression pressures. D When used as a solution to the unknowns i and s in PWV, these are obtained respectively. 。 4. The blood pressure monitoring device (10; 110) according to claim 3, characterized in that, The propagation time between the minimum portions of the pulse wave obtained according to the actual pressure is the propagation time between the apex generated corresponding to the rising point of the pulse wave obtained according to the actual pressure in the second differential waveform of the pulse wave obtained according to the actual pressure.

5. The blood pressure monitoring device (10; 110) according to claim 3, characterized in that, The blood pressure estimation unit (94; 194) includes a minimum blood pressure estimation unit, which, for the subject (14), uses the actual compression pressure in the low-pressure range as Pc and the actual pulse wave velocity obtained under the actual compression pressure as PWV. D The inherent relationship of Equation (2) is applied successively to estimate the estimated minimum blood pressure value.

6. The blood pressure monitoring device (10; 110) according to claim 1, characterized in that, The estimated blood pressure value estimated by the blood pressure estimation unit (94; 194) is the estimated highest blood pressure value SAPe of the subject. When the pulse wave propagation velocity of a living organism is set as PWV, the highest blood pressure of a living organism is set as SAP, and the compression pressure of a living organism is set as Pc, the linear relationship is represented by the regression line of the following equation (3). Where s represents the slope of the regression line and i represents the intercept of the regression line.

7. The blood pressure monitoring device (10; 110) according to claim 6, characterized in that, When i S and s S When used as a measured correction value, the inherent relationship of the measured object (14) is represented by the following equation (4), where i S and s S The actual pulse wave propagation velocity (PWV) is obtained by substituting the highest blood pressure value measured for the subject into the two equations represented by equation (3), respectively, into the different actual compression pressures within the low-pressure range, respectively, into the actual pulse wave propagation velocity (Pc), respectively, into the propagation time between the maxima of the pulse wave obtained according to the different actual compression pressures. S When used as a solution to the unknowns i and s in PWV, it is obtained. 。 8. The blood pressure monitoring device (10; 110) according to claim 7, characterized in that, The propagation time between the maxima of the pulse waves obtained according to the actual pressure is the propagation time between the maxima of the pulse waves obtained according to the actual pressure.

9. The blood pressure monitoring device (10; 110) according to claim 7, characterized in that, The blood pressure estimation unit (94; 194) includes a maximum blood pressure estimation unit (98; 198), which, for the subject (14), uses the actual compression pressure in the low-pressure range as Pc and the actual pulse wave velocity obtained under the actual compression pressure as PWV. S The inherent relationship of Equation (4) is applied successively to estimate the estimated maximum blood pressure value.

10. The blood pressure monitoring device (10; 110) according to claim 1, characterized in that, The estimated blood pressure value estimated by the blood pressure estimation unit (94; 194) is the estimated notched blood pressure value DNAPe of the subject (14), which is the pressure at the notched site formed locally after the maximum position of the pulse wave obtained according to the actual pressure. When the pulse wave propagation velocity of a living organism is set as PWV, the notch blood pressure value of a living organism is set as DNAP, and the compression pressure of a living organism is set as Pc, the linear relationship is represented by the regression line of the following equation (5). Where s represents the slope of the regression line and i represents the intercept of the regression line.

11. The blood pressure monitoring device (10; 110) according to claim 10, characterized in that, When i DN and s DN When used as a measured correction value, the inherent relationship of the measured object (14) is represented by the following equation (6), where i DN and s DN The actual pulse wave propagation velocity (PWV) is obtained by substituting the measured notched blood pressure value for the subject into the two equations represented by equation (5), respectively, into the different actual compression pressures within the low-pressure range, respectively, into the actual pulse wave propagation velocity (Pc), respectively, into the propagation time between the notched parts of the pulse wave obtained according to the different actual compression pressures. DN When used as a solution to the unknowns i and s in PWV, it is obtained. 。 12. The blood pressure monitoring device (10; 110) according to claim 11, characterized in that, The propagation time between the notches of the pulse waves obtained according to the actual pressure is the propagation time between the apexes generated after the time point corresponding to the maximum portion of the pulse waves obtained according to the actual pressure in the second differential waveform of the pulse waves obtained according to the actual pressure.

13. The blood pressure monitoring device (10; 110) according to claim 11, characterized in that, The blood pressure estimation unit (94; 194) includes a notched blood pressure estimation unit, which, for the subject (14), uses the actual compression pressure in the low-pressure zone as Pc and the actual pulse wave velocity obtained under the actual compression pressure as PWV. DN The inherent relationship of Equation (6) is applied successively to estimate the estimated notch blood pressure value.

14. The blood pressure monitoring device (10; 110) according to claim 13, characterized in that, The blood pressure estimation unit (94; 194) includes: The minimum blood pressure estimation unit (96; 196) applies, for the subject (14), the actual compression pressure in the low-pressure zone and the actual pulse wave propagation velocity obtained under the actual compression pressure to the inherent relationship between the measured minimum blood pressure value, the actual compression pressure in the low-pressure zone, and the actual pulse wave propagation velocity in the low-pressure zone, thereby estimating the estimated minimum blood pressure value of the subject; and The maximum blood pressure estimation unit (98; 198) generates a relationship between the magnitude of the pulse wave in the low-pressure range and the estimated blood pressure value based on the estimated minimum blood pressure value estimated by the minimum blood pressure estimation unit and the estimated notch blood pressure value estimated by the notch blood pressure estimation unit (200). The estimated maximum blood pressure value is estimated by applying the maximum value of the actual pulse wave obtained successively to the relationship.

15. The blood pressure monitoring device (10; 110) according to any one of claims 1 to 14, characterized in that, include: The pressure control unit (86; 186) causes the multiple pressures in the low-pressure zone to be reduced in stages, so as to form multiple zones that are temporarily maintained at a certain value in the low-pressure zone. The pulse wave extraction unit (88; 188) extracts pulse waves, which are pressure vibrations generated synchronously with the pulse in the multiple expansion bags (22, 24, 26) under the pressure in the multiple intervals. as well as The pulse wave propagation velocity calculation unit (90; 190) calculates the pulse wave propagation velocity based on the time difference of the pulse waves obtained in the plurality of intervals and the distance between the plurality of expansion bags.

16. The blood pressure monitoring device (10; 110) according to any one of claims 1 to 14, characterized in that, The compression band (12) has an independent upstream expansion bag (22), an intermediate expansion bag (24) and a downstream expansion bag (26) that are connected in the width direction to compress the compressed part (16) of the living body (14). The upstream expansion bag, the intermediate expansion bag and the downstream expansion bag compress the artery (18) in the compressed part with the same pressure.

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