Blood pressure monitoring device

Abstract

To provide a blood pressure monitoring device capable of estimating blood pressure at a short time interval while reducing a burden on a living body.SOLUTION: In a blood pressure monitoring device 10, a unique relation generation unit 92 applies an actual measured blood pressure value APR, actual pressing pressures PcH1 and PcH2 in a low pressure section, and actual pulse wave propagation velocities PWV1 and PWV2 in the low pressure section to a linear relation stored beforehand between a squared value PWV2 of the pulse wave propagation velocity detected under a plurality of pressing pressures Pc of a cuff respectively in the low pressure section lower than a diastolic blood pressure DAP of a living body and a wall penetrating pressure of the artery (=blood pressure value AP-pressing pressure Pc), and generates a unique relation of the living body among the blood pressure value AP, the pressing pressure Pc, and the pulse wave propagation velocities PWV. A blood pressure estimation unit 94 calculates an estimated blood pressure APe of the living body by sequentially applying the actual pressing pressure PcHm and the pulse wave propagation velocities PWVm acquired in the low pressure section to the unique relation.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a blood pressure monitoring device including a compression band that is wound around a compressed part which is a limb of a living body.

Background Art

[0002] In a commonly used non-invasive blood pressure measurement device, in the pressure reduction period after raising the compression pressure by the compression band to a compression pressure equal to or higher than the maximum blood pressure value of the person to be measured, the blood pressure value of the person to be measured is determined based on the change in the plethysmogram obtained as the pressure vibration of the compression band. For example, the automatic blood pressure measurement device described in Patent Document 1 is such a device.

[0003] In the automatic blood pressure measurement device described in Patent Document 1, a compression band having three expansion bags that respectively form three independent air chambers is used. After the compression pressure by the compression band is increased to a target pressure value set higher than the maximum blood pressure value of the living body, the maximum blood pressure value and the minimum blood pressure value are determined based on the change in the amplitude of the pulse wave signal collected during the pressure reduction period to a measurement end pressure value set lower than the minimum blood pressure value of the living body. Alternatively, the maximum blood pressure value is determined based on the amplitude ratio of two pulse wave signals collected from two expansion bags during the pressure reduction period, and the minimum blood pressure value is determined based on the time difference between the two pulse wave signals.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, according to the above-mentioned conventional blood pressure measuring device, the pressure of the compression band is increased to a target pressure value set higher than the maximum blood pressure value of the living body. For this reason, since the pressure by the compression band is increased until the arteries of the limbs of the living body around which the compression band is wound are stopped from bleeding, there are drawbacks that it gives uneasiness to the living body about how strongly it is compressed and that the burden on the living body is large. For example, since the tightening force by the compression band is increased until the arteries of the limbs of the living body are stopped from bleeding, it gives uneasiness to the living body, and there are cases where the mental state of the living body becomes unstable during measurement and the accuracy of blood pressure measurement cannot be obtained. Also, when continuously monitoring the blood pressure value of the living body under free movement for 24 hours, if the tightening force by the compression band is increased until the arteries of the limbs of the living body are stopped from bleeding, the stress on the living body is large, and there are cases where the accuracy of the blood pressure measurement value under free movement cannot be obtained. Further, it is necessary to compress with the compression band until bleeding stops at the maximum blood pressure value of the living body, and then lower the compression pressure until the minimum blood pressure value of the living body. The intermittent measurement once takes time and the measurement is discontinuous, and there are cases where blood pressure fluctuations in a shorter time cannot be detected.

[0006] The present invention has been made in view of the above circumstances, and an object thereof is to provide a blood pressure monitoring device capable of reducing the burden on a living body in continuous blood pressure measurement and the like.

Means for Solving the Problem

[0007] The inventors of the present invention, while examining the relationship between the compression pressure by the compression band and the pulse wave propagation velocity of the artery, found that in the range where the compression pressure is lower than the minimum blood pressure value of the living body, the relationship between the transmural pressure of the artery (blood pressure in the artery - compression pressure) and the square value of the pulse wave propagation velocity is shown by a regression line. Further, from the regression line, the actual blood pressure value, actual compression pressure, and pulse wave propagation velocity of the living body, a unique relationship for the subject between the maximum blood pressure value, minimum blood pressure value, or maximum blood pressure value and minimum blood pressure value, and the compression pressure and pulse wave propagation velocity related values is generated, and when applying a plurality of actual sets of compression pressure and pulse wave propagation velocity to the unique relationship, it was found that the blood pressure value of the living body can be estimated. The present invention has been made based on such findings.

[0008] That is, the gist of the first invention is a blood pressure monitoring device having a plurality of inflatable bags that form independent air chambers arranged in the width direction, and a compression band that is wound around a compressed part of the subject to compress the artery of the subject, and repeatedly estimates the estimated blood pressure value of the subject. The device includes a linear relationship storage unit that stores a pre-stored linear relationship between the square value of the pulse wave propagation velocity respectively detected under a plurality of compression pressures of the compression band in a low pressure section lower than the minimum blood pressure value of the living body, and a plurality of transmural pressures of the artery that are the pressure differences between the blood pressure value in the artery and the compression pressure of the compression band; a blood pressure measurement unit that measures the actual blood pressure value of the subject based on a pulse synchronous wave from the artery obtained during a blood pressure drop process after compressing the compressed part of the subject with a compression pressure higher than the maximum blood pressure value of the subject; a specific relationship generation unit that generates a specific relationship for the subject among the actual blood pressure value, the actual compression pressure, and the actual pulse wave propagation velocity of the subject by applying the actual blood pressure value, the actual compression pressure in the low pressure section, and the actual pulse wave propagation velocity obtained under the actual compression pressure of the subject to the linear relationship; and a blood pressure estimation unit that estimates the estimated blood pressure value by applying the actual compression pressure in the low pressure section and the actual pulse wave propagation velocity obtained under the actual compression pressure of the subject to the specific relationship for the subject.

[0009] The gist of the second invention is that, 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, and the linear relationship is a regression line represented by the following formula (1), where the pulse wave propagation velocity of the living body is PWV, the minimum blood pressure value of the living body is DAP, and the compression pressure of the living body is Pc. PWV 2 =s·(DAP - Pc)+i ··· (1) However, s represents the slope of the regression line, and i represents the intercept of the regression line.

[0010] The gist of the third invention is that, in the second invention, the specific relationship of the subject is two equations respectively represented by formula (1), to which the minimum blood pressure value DAP actually measured for the subjectR Substitute each into DAP, substitute each of the different actual compression pressures Pc within the low pressure range, and based on the propagation time between the minimum parts of the pulse waves obtained for each of the different actual compression pressures, the actual pulse wave velocity PWV D When each is substituted as PWV, i obtained respectively as the solutions of the unknowns i and s D and s D Taking them as the actually measured calibration values, it is that which is represented by the following formula (2). DAPe = PWV D 2 / s D -i D / s D + Pc ··· (2)

[0011] The gist of the fourth invention is that in the third invention, the propagation time between the minimum parts of the pulse waves obtained for each of the actual compression pressures is the propagation time between the peaks that occur corresponding to the rising points of the pulse waves obtained for each of the actual compression pressures in the second derivative waveforms of the pulse waves obtained for each of the actual compression pressures.

[0012] The gist of the fifth invention is that in the third or fourth invention, the blood pressure estimation unit includes a minimum blood pressure estimation unit that estimates the estimated minimum blood pressure value by sequentially applying the actual compression pressure in the low pressure range and the actual pulse wave velocity obtained under the actual compression pressure to the intrinsic relationship of formula (2) for the subject to be measured.

[0013] The gist of the sixth invention is that 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 to be measured, and the linear relationship is a regression line represented by the following formula (3) where the pulse wave velocity of the living body is PWV, the maximum blood pressure value of the living body is SAP, and the compression pressure of the living body is Pc. PWV 2 = s·(SAP - Pc)+ i ··· (3) However, s indicates the slope of the regression line, and i indicates the intercept of the regression line.

[0014] The gist of the seventh invention is that, in the sixth invention, the unique relationships of the subject to be measured are respectively substituted into the two equations expressed by formula (3) with the maximum blood pressure value SAP actually measured for the subject to be measured Show substituted as SAP, and the different actual compression pressures Pc within the low pressure range are respectively substituted, and based on the propagation time between the maximum parts of the pulse waves respectively obtained for each of the different actual compression pressures, the actual pulse wave velocity PWV R is substituted as PWV, and when i and s obtained as solutions of the unknowns i and s are taken as the actually measured calibration values, it is that which is represented by the following formula (4). S SAPe = PWV S / s S -i SAPe = PWV S 2 / s S -i S / s S +Pc ··· (4)

[0015] The gist of the eighth invention is that, in the seventh invention, the propagation time between the maximum parts of the pulse waves respectively obtained for each of the actual compression pressures is the propagation time between the maximum points of the pulse waves respectively obtained for each of the actual compression pressures.

[0016] The gist of the ninth invention is that, in the seventh or eighth invention, the blood pressure estimation unit includes a maximum blood pressure estimation unit that estimates the estimated maximum blood pressure value by sequentially applying the actual compression pressure and the actual pulse wave velocity obtained under the actual compression pressure within the low pressure range to the unique relationship of formula (4) for the subject to be measured.

[0017] The gist of the tenth invention is that, in the first invention, the estimated blood pressure value estimated by the blood pressure estimation unit is Of the pulse wave the estimated notch blood pressure value DNAPe of the subject to be measured, which is the blood pressure at the time of occurrence of the notch part locally formed after the maximum part, and the linear relationship is the regression line represented by the following formula (5) when the pulse wave velocity of the living body is PWV, the notch blood pressure value of the living body is DNAP, and the compression pressure of the living body is Pc. PWV2 = s·(DNAP - Pc)+ i ··· (5) However, s represents the slope of the regression line, and i represents the intercept of the regression line.

[0018] The gist of the 11th invention is that, in the 10th invention, for the unique relationship of the subject to be measured, the notch blood pressure values actually measured for the subject to be measured are respectively substituted as DNAP into two equations represented by the following formula (5), and the different actual compression pressures within the low-pressure range are respectively substituted as Pc, and the actual pulse wave velocity PWV based on the propagation time between the notch sites of the pulse waves respectively obtained for each of the different actual compression pressures DN When PWV is respectively substituted as PWV, the i DN and s DN obtained as the solutions of the unknowns i and s are taken as the actual measurement calibration values, and it lies in that it is represented by the following formula (6). DNAPe = PWV DN 2 / s DN - i DN / s DN + Pc ··· (6)

[0019] The gist of the 12th invention is that, in the 11th invention, the propagation time between the notch sites of the pulse waves respectively obtained for each of the actual compression pressures is the propagation time between the peaks occurring after the time points corresponding to the maximum sites of the pulse waves respectively obtained for each of the actual compression pressures in the second derivative waveform of the pulse waves respectively obtained for each of the actual compression pressures.

[0020] The gist of the 13th invention is that, in the 11th invention or the 12th invention, the blood pressure estimation unit includes a notch blood pressure estimation unit that estimates the estimated notch blood pressure value by sequentially applying the actual compression pressure and the actual pulse wave velocity obtained under the actual compression pressure in the low-pressure range to the unique relationship of the formula (6) for the subject to be measured.

[0021] The gist of the 14th invention is that, in the 13th invention, the blood pressure estimation unit measures, for the subject, the actual compression pressure in the low-pressure section and the actual pulse wave propagation velocity obtained under the actual compression pressure, and applies them to the inherent relationship among the lowest blood pressure value actually measured for the subject, the actual compression pressure in the low-pressure section, and the actual pulse wave propagation velocity in the low-pressure section, thereby estimating the estimated lowest blood pressure value of the subject. Based on the estimated lowest blood pressure value estimated by the lowest blood pressure estimation unit and the estimated notch blood pressure value estimated by the notch blood pressure estimation unit, a relationship between the magnitude of the pulse wave and the estimated blood pressure value in the low-pressure section is generated, and the estimated maximum blood pressure value is estimated by applying the maximum value of the actual pulse wave sequentially obtained in the relationship. That is, it includes a lowest blood pressure estimation unit and a highest blood pressure estimation unit.

[0022] The gist of the 15th invention is that, in any one of the inventions from the 1st to the 14th invention, a compression pressure control unit that stepwise reduces the pressure to form a plurality of sections that temporarily maintain a constant value for a plurality of compression pressures within the low-pressure section; a pulse wave extraction unit that extracts a pulse wave, which is a pressure vibration generated in synchronization with the pulse in each of the plurality of expansion bags under the compression pressure in the plurality of sections; and a pulse wave propagation velocity calculation unit that calculates the pulse wave propagation velocity based on the time difference of the pulse waves respectively obtained in the plurality of sections and the distance between the plurality of expansion bags. That is, it includes these components.

[0023] The gist of the 16th invention is that, in any one of the inventions from the 1st to the 15th invention, the compression band is wound around the compressed part of the living body and has independent upstream expansion bags, intermediate expansion bags, and downstream expansion bags arranged in the width direction to compress the compressed part of the living body respectively, and the upstream expansion bags, the intermediate expansion bags, and the downstream expansion bags compress the artery in the compressed part with the same compression pressure respectively.

Effect of the Invention

[0024] According to the blood pressure monitoring device of the first invention, in a low-pressure section lower than the minimum blood pressure value of the living body, the square value of the pulse wave propagation velocity respectively detected under the plurality of compression pressures of the compression band, and the blood pressure value in the artery and the compression pressure of the compression band A linear relationship storage unit that stores a previously stored linear relationship between a plurality of transmural pressures of the artery, which is the pressure difference; and the actual blood pressure value, the actual compression pressure in the low-pressure section, and the actual compression pressure for the subject to be measured. A specific relationship generation unit that generates a specific relationship for the subject to be measured among the actual blood pressure value, the actual compression pressure, and the actual pulse wave propagation velocity by applying the actual pulse wave propagation velocity based on the propagation time between the pulse waves obtained below to the linear relationship; and for the subject to be measured, the actual compression pressure in the low-pressure section and the actual pulse wave propagation velocity obtained under the actual compression pressure are applied to the specific relationship for the subject to be measured, thereby estimating the estimated blood pressure value. A blood pressure estimation unit. As a result, except when measuring the actual blood pressure value of the subject by the blood pressure measurement unit, when estimating the estimated blood pressure value, the compression pressure by the compression band is set to a value lower than the minimum blood pressure value of the subject, so the burden on the subject is reduced and more continuous blood pressure measurement can be performed.

[0025] According to the blood pressure monitoring devices of the second and third inventions, in the specific relationship generation unit, based on the minimum blood pressure value actually measured for the subject to be measured, the actual compression pressure, and the pulse wave propagation velocity based on the propagation time between the minimum parts of the pulse waves obtained under the actual compression pressure, the specific relationship of the subject to be measured among the minimum blood pressure value, the compression pressure, and the pulse wave propagation velocity is generated. As a result, the blood pressure estimation unit applies the pulse wave propagation velocity based on the time difference between the minimum parts between the actual compression pressure obtained in the low-pressure section lower than the estimated minimum blood pressure value and the pulse waves obtained under the actual compression pressure to the relationship specific to the living body generated by the specific relationship generation unit, thereby easily estimating the estimated minimum blood pressure value of the subject to be measured.

[0026] According to the blood pressure monitoring device of the fourth invention, the propagation time between the minimum parts of the pulse waves respectively obtained for each of the actual compression pressures is the propagation time between the peaks that occur corresponding to the rising points of the pulse waves respectively obtained for each of the actual compression pressures in the second differential waveform of the pulse waves respectively obtained for each of the actual compression pressures. By doing so, the propagation time between the minimum parts of the pulse wave can be easily obtained, and the estimation accuracy of the estimated minimum blood pressure value can be improved.

[0027] According to the blood pressure monitoring device of the fifth invention, the blood pressure estimation unit includes a minimum blood pressure estimation unit that estimates the estimated minimum blood pressure value by sequentially applying the actual compression pressure in the low pressure section and the actual pulse wave propagation speed obtained under the actual compression pressure for the subject to the intrinsic relationship of the formula (2). Therefore, the estimated minimum blood pressure value of the subject can be easily estimated.

[0028] According to the blood pressure monitoring devices of the sixth and seventh inventions, in the intrinsic relationship generation unit, the intrinsic relationship of the subject between the maximum blood pressure value and the compression pressure and the pulse wave propagation speed is generated using the maximum blood pressure value actually measured for the subject, the actual compression pressure, and the pulse wave propagation speed based on the propagation time between the maximum parts of the pulse waves obtained under the actual compression pressure. Thereby, the blood pressure estimation unit can estimate the estimated maximum blood pressure value of the subject by applying the pulse wave propagation speed based on the time difference between the maximum parts between the actual compression pressure obtained in the low pressure section lower than the minimum blood pressure value and the pulse waves obtained under the actual compression pressure to the intrinsic relationship of the subject generated by the relationship generation unit.

[0029] According to the blood pressure monitoring device of the eighth invention, the propagation time between the maximum parts of the pulse waves respectively obtained for each of the actual compression pressures is the propagation time between the maximum points of the pulse waves respectively obtained for each of the actual compression pressures. By doing so, the propagation time between the maximum parts of the pulse wave can be easily obtained, and the estimation accuracy of the estimated maximum blood pressure value can be improved.

[0030] According to the blood pressure monitoring device of the ninth invention, the systolic blood pressure estimation unit includes a systolic blood pressure estimation unit that estimates the estimated systolic blood pressure value by sequentially applying the actual compression pressure and the actual pulse wave propagation velocity obtained under the actual compression pressure in the low pressure section to the intrinsic relationship of equation (4) for the subject. Therefore, the estimated systolic blood pressure value of the subject can be easily estimated.

[0031] According to the blood pressure monitoring devices of the tenth and eleventh inventions, in the intrinsic relationship generation unit, the intrinsic relationship of the subject between the notch blood pressure value actually measured for the subject, the actual compression pressure, and the pulse wave propagation velocity based on the propagation time between the notch portions of the pulse wave obtained under the actual compression pressure is generated. Thereby, the blood pressure estimation unit can easily estimate the notch blood pressure value of the subject by applying the pulse wave propagation velocity based on the time difference between the notch portions between the pulse waves obtained under the actual compression pressure obtained in the low pressure section lower than the diastolic blood pressure value and the actual compression pressure to the relationship specific to the living body generated by the relationship generation unit.

[0032] According to the blood pressure monitoring device of the twelfth invention, the propagation time between the notch portions of the pulse wave obtained for each actual compression pressure is the propagation time between the peaks occurring after the time point corresponding to the maximum portion of the pulse wave obtained for each actual compression pressure in the second derivative waveform of the pulse wave obtained for each actual compression pressure. In this way, the propagation time between the notch portions of the pulse wave can be easily obtained, and the estimation accuracy of the notch blood pressure value is improved.

[0033] According to the blood pressure monitoring device of the thirteenth invention, the blood pressure estimation unit includes a notch blood pressure estimation unit that estimates the estimated notch blood pressure value by sequentially applying the actual compression pressure and the actual pulse wave propagation velocity obtained under the actual compression pressure in the low pressure section to the intrinsic relationship of equation (6) for the subject. Therefore, the estimated notch blood pressure value of the subject can be easily estimated.

Brief Description of the Drawings

[0037]

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Mode for Carrying Out the Invention

[0038] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following embodiments, the drawings are appropriately simplified or deformed, and the dimensional ratios, shapes, etc. of each part are not necessarily drawn accurately.

Embodiment

[0039] FIG. 1 shows a blood pressure monitoring device 10 (automatic blood pressure measuring device) that also functions as an example of a blood pressure estimation device of the present invention, which includes a compression band 12 for the upper arm wound around a compression site, such as the upper arm 16, which is a limb of a living body, such as the arm or ankle, of the living body 14 to be measured. In the process of reducing the compression pressure Pc of the compression band 12 that has been pressurized to a value sufficient to stop the blood flow in the artery 18 in the upper arm 16, the blood pressure monitoring device 10 sequentially extracts the pulse wave, which is the pressure vibration of the compression pressure Pc in the compression band 12 generated in response to the volume change of the artery 18, and measures the maximum blood pressure value SAP and the minimum blood pressure value DAP of the living body 14 based on the information obtained from the pulse wave.

[0040] FIG. 2 is a view showing the compression band 12 with a part of the outer peripheral side nonwoven fabric 20a cut out. As shown in FIG. 2, the compression band 12 includes a belt-shaped outer bag 20 composed of an outer peripheral side nonwoven fabric 20a and an inner peripheral side nonwoven fabric 20b made of synthetic resin fibers whose back surfaces are laminated to each other by a synthetic resin such as PVC (polyvinyl chloride), and flexible sheets such as soft polyvinyl chloride sheets that are sequentially accommodated in the width direction within the belt-shaped outer bag 20 and are capable of independently compressing the upper arm 16, namely, an upstream expansion bag 22, an intermediate expansion bag 24, and a downstream expansion bag 26. This compression band 12 is detachably attached to the upper arm 16 by detachably adhering a fleece pile 28b attached to the end of the inner peripheral side nonwoven fabric 20b to a hook-and-loop fastener 28a attached to the end of the outer peripheral side nonwoven fabric 20a.

[0041] The upstream expansion bag 22, the intermediate expansion bag 24, and the downstream expansion bag 26 each have independent air chambers that are arranged in the width direction of the long compression band 12 and compress the upper arm 16 respectively, and are provided with pipe connection connectors 32, 34, and 36 on the outer peripheral surface side. These pipe connection connectors 32, 34, and 36 are exposed on the outer peripheral surface of the compression band 12 through the outer peripheral side nonwoven fabric 20a.

[0042] FIG. 3 is a plan view showing an upstream expansion bag 22, an intermediate expansion bag 24, and a downstream expansion bag 26 provided in the compression band 12, and FIG. 4 is a sectional view taken along line IV-IV of FIG. 3. The upstream expansion bag 22, the intermediate expansion bag 24, and the downstream expansion bag 26 are for detecting a pulse wave, which is a pressure vibration generated in response to a volume change of the artery 18 compressed by them, and each has a longitudinal shape. The upstream expansion bag 22 and the downstream expansion bag 26 are arranged adjacent to both sides of the intermediate expansion bag 24, and the intermediate expansion bag 24 is arranged at the center in the width direction of the compression band 12 in a state of being sandwiched between the upstream expansion bag 22 and the downstream expansion bag 26. The center of the upstream expansion bag 22 and the center of the intermediate expansion bag 24 are separated by a distance L12, and the center of the upstream expansion bag 22 and the center of the downstream expansion bag 26 are separated by a distance L13. In a state where the compression band 12 is 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 longitudinal direction of the upper arm 16, and the intermediate expansion bag 24 is arranged between the upstream expansion bag 22 and the downstream expansion bag 26 so as to be continuous in the longitudinal direction of the upper arm 16.

[0043] The intermediate expansion bag 24 is provided with so-called machi-structure side edges on both sides. That is, at both ends of the intermediate expansion bag 24 in the longitudinal direction of the upper arm 16, that is, in the width direction of the compression band 12, a pair of folding grooves 24f, 24g each formed of a flexible sheet folded in a direction approaching each other so as to become deeper as they approach each other are formed. And the end portions 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 folding grooves 24f, 24g and arranged. Thereby, the end portion 24a of the intermediate expansion bag 24 and the end portion 22a of the upstream expansion bag 22 are overlapped with each other, and the end portion 24b of the intermediate expansion bag 24 and the end portion 26a of the downstream expansion bag 26 are overlapped with each other, that is, an overlap structure is formed. Therefore, an even pressure distribution can be obtained even in the vicinity of their boundaries when the upstream expansion bag 22, the intermediate expansion bag 24, and the downstream expansion bag 26 compress the upper arm 16 at an equal pressure.

[0044] The upstream expansion bag 22 and the downstream expansion bag 26 also have side edges of the machi structure at ends 22b and 26b on the side opposite to the intermediate expansion bag 24. That is, at the end 22b of the upstream expansion bag 22 on the side opposite to the intermediate expansion bag 24, a folding groove 22f formed of a flexible sheet folded in a direction approaching each other so as to become deeper as they approach each other is formed. Further, at the end 26b of the downstream expansion bag 26 on the side opposite to the intermediate expansion bag 24, a folding groove 26g formed of a flexible sheet folded in a direction approaching each other so as to become deeper as they approach each other is formed. So as not to protrude in the width direction of the compression band 12, the sheet constituting the folding groove 22f is connected to the opposite side portion, that is, the portion on the intermediate expansion bag 24 side, via a connection sheet 38 having a through hole disposed in the upstream expansion bag 22. Similarly, the sheet constituting the folding groove 26g is connected to the opposite side portion, that is, the portion on the intermediate expansion bag 24 side, via a connection sheet 40 having a through hole disposed in the downstream expansion bag 26.

[0045] Thereby, even at the ends 22b and 26b of the upstream expansion bag 22 and the downstream expansion bag 26, the compression pressure Pc on the artery 18 of the upper arm 16 can be obtained in the same manner as in other portions, so that the effective compression width in the width direction of the compression band 12 becomes equivalent to its width dimension. The width direction of the compression band 12 is about 12 cm, and since the three upstream expansion bag 22, the intermediate expansion bag 24, and the downstream expansion bag 26 are arranged in the width direction, each must have a width dimension of substantially about 4 cm. In order to sufficiently generate the compression function even with such a narrow width dimension, an overlap structure is adopted in which both ends 24a and 24b of the intermediate expansion bag 24 and the ends 22a of the upstream expansion bag 22 and the ends 26a of the downstream expansion bag 26 are overlapped with each other, and the ends 22b and 26b of the upstream expansion bag 22 and the downstream expansion bag 26 on the side opposite to the intermediate expansion bag 24 are the side edges of the so-called machi structure.

[0046] Between the ends 22a and 26a on the side of the intermediate expansion bag 24 of the upstream expansion bag 22 and the downstream expansion bag 26 and the inner wall surfaces of the pair of folding grooves 24f, 24g into which they are inserted, that is, the groove side surfaces facing each other, longitudinal shielding members 42n, 42m having anisotropy of rigidity with a higher bending rigidity in the width direction of the compression belt 12 than the bending rigidity in the longitudinal direction of the compression belt 12 are respectively interposed. The shielding member 42n has a length dimension similar to the overlapping dimension between the upstream expansion bag 22 and the intermediate expansion bag 24. Similarly, the shielding member 42m has a length dimension similar to the overlapping dimension between the downstream expansion bag 26 and the intermediate expansion bag 24.

[0047] As shown in FIGS. 3 and 4, in the outer peripheral side gaps of the gaps between the end 22a of the upstream expansion bag 22 and the folding groove 24f into which it is inserted, and in the outer peripheral side gaps of the gaps between the end 26a of the downstream expansion bag 26 and the folding groove 24g into which it is inserted, longitudinal shielding members 42n, 42m are respectively interposed. In this embodiment, since the shielding effect is greater in the outer peripheral side gap than in the inner peripheral side gap, the longitudinal shielding members 42n, 42m are provided in the outer peripheral side gap, but they may be provided in both the outer peripheral side gap and the inner peripheral side gap.

[0048] The shielding members 42n, 42m are formed by arranging a plurality of flexible hollow tubes 44 made of resin parallel to each other in the longitudinal direction of the upper arm 16 (that is, the width direction of the compression belt 12) in a state parallel to each other, and arranging them in the circumferential direction of the upper arm 16 (that is, the longitudinal direction of the compression belt 12). The flexible hollow tubes 44 are directly or indirectly connected to each other by molding or adhesion, or through other members such as a flexible sheet like an adhesive tape. The shielding member 42n is hooked on a plurality of latching sheets 46 provided at a plurality of locations on the outer peripheral side of the end 22a on the side of the intermediate expansion bag 24 of the upstream expansion bag 22. Similarly, the shielding member 42m is hooked on a plurality of latching sheets 46 provided at a plurality of locations on the outer peripheral side of the end 26a on the side of the intermediate expansion bag 24 of the downstream expansion bag 26.

[0049] Returning to FIG. 1, in the blood pressure monitoring device 10, an air pump 50, a rapid exhaust valve 52, and an exhaust control valve 54 are respectively connected to a main pipe 56. From the main pipe 56, 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 are respectively branched. The first branch pipe 58 is provided with a first on-off valve E1 for directly opening and closing between the air pump 50 and the upstream expansion bag 22. The second branch pipe 62 is provided with a second on-off valve E2 for directly opening and closing between the air pump 50 and the intermediate expansion bag 24. The third branch pipe 64 is provided with a third on-off valve E3 for directly opening and closing between the air pump 50 and the downstream expansion bag 26.

[0050] A first pressure sensor T1 for detecting the pressure value in the upstream expansion bag 22 is connected to the first branch pipe 58, a second pressure sensor T2 for detecting the pressure value in the intermediate expansion bag 24 is connected to the second branch pipe 62, a third pressure sensor T3 for detecting the pressure value in the downstream expansion bag 26 is connected to the third branch pipe 64, and a fourth pressure sensor T4 for detecting the compression pressure Pc of the compression band 12 is connected to the main pipe 56.

[0051] An output signal indicating the pressure value in the upstream expansion bag 22, that is, the compression pressure Pc1 of the upstream expansion bag 22, is supplied from the first pressure sensor T1 to the electronic control device 70, an output signal indicating the pressure value in the intermediate expansion bag 24, that is, the compression pressure Pc2 of the intermediate expansion bag 24, is supplied from the second pressure sensor T2, an output signal indicating the pressure value in the downstream expansion bag 26, that is, the compression pressure Pc3 of the downstream expansion bag 26, is supplied from the third pressure sensor T3, and an output signal indicating the compression pressure Pc of the compression band 12 is supplied from the fourth pressure sensor T4.

[0052] The electronic control device 70 is a so-called microcomputer including a CPU 72, a RAM 74, a ROM 76, a display device 78, and I / O ports (not shown). The electronic control device 70 processes input signals according to a program stored in the ROM 76 in advance while the CPU 72 utilizes the storage function of the RAM 74, and in response to the operation of the blood pressure estimation start operation button 80, controls an electric air pump 50, a rapid exhaust valve 52, an exhaust control valve 54, a first on-off valve E1, a second on-off valve E2, and a third on-off valve E3 respectively, thereby executing automatic blood pressure measurement control and displaying the measurement results on the display device 78.

[0053] FIG. 5 is a functional block diagram for explaining the main part of the control function provided in the electronic control device 70. In FIG. 5, the electronic control device 70 functionally includes a blood pressure estimation unit 94 having 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 speed calculation unit 90, an intrinsic relationship generation unit 92, a minimum blood pressure estimation unit 96, and a maximum blood pressure estimation unit 98. FIG. 6 is a time chart for explaining the main part of the compression pressure control operation of the compression band 12 by the compression pressure control unit 86.

[0054] The linear relationship storage unit 82 stores in advance the stored linear relationship between the square value PWV of a plurality of pulse wave propagation speeds PWV respectively detected under a plurality of compression pressures Pc of the compression band 12 in a low pressure section lower than the minimum blood pressure value DAP of the living body 14, the blood pressure value AP in the artery 18, and the transmural pressure (AP - Pc) of the artery 18 which is the pressure difference between the blood pressure value AP and the compression pressure Pc. Specifically, for the minimum blood pressure value DAP, a regression line which is a linear relationship represented by the formula (1) is stored, and for the maximum blood pressure value SAP, a regression line which is a linear relationship represented by the formula (3) is stored. 2 PWV

[0055] PWV 2 = s·(DAP - Pc)+ i ··· (1) PWV 2 = s·(SAP - Pc)+ i ··· (3) However, s indicates the slope of the regression line, and i indicates the intercept of the regression line.

[0056] The regression line described above will be explained below. Generally, the following Bramwell Hill's equation (7) is known for the pulse wave velocity in an artery. In equation (7), V is the volume of the artery, P is the blood pressure in the artery, and ρ is the density of blood. Here, when the cross-sectional area of the blood vessel is A and the distance between the expansion bags is L, the artery volume V is expressed by equation (8). Differentiating both sides of equation (6) by A results in equation (9).

[0057] PWV = √((V·dP) / (ρ·dV)) ··· (7) V = A·L ··· (8) dV = dA·L ··· (9)

[0058] In addition, an exponential function model equation including the exponential function constant Po and the coefficient α shown in equation (10) has been established for the blood pressure P and the cross-sectional area A of the blood vessel, and equation (10) can be rewritten as equation (11). Here, for the sake of simplicity, when the density ρ is set to 1, from equations (7), (9), and (11), the relationship between the pulse wave velocity PWV and the blood pressure value AP is expressed by equation (12).

[0059] P = Po·e αA ··· (10) dP = α·P·dA ··· (11) PWV 2 = P·Ln(P / Po) ··· (12)

[0060] When the minimum blood pressure value DAP of the living body is stable, when the compression pressure Pc by the compression band 12 is changed in a pressure range (low pressure section) lower than the minimum blood pressure value DAP of the living body, the transmural pressure (DAP - Pc), which is the pressure difference applied to the blood vessel wall of the artery 18, and the pulse wave velocity PWV change while sequentially corresponding to each individual pulse. Therefore, the above equation (12) is replaced by the following mathematical model equation (13) at a certain pulse.

[0061] PWV 2 =(DAP - Pc)·Ln((DAP - Pc) / Po)···(13) However, Pc < DAP

[0062] In the above formula (13), the term Ln((DAP - Pc) / Po) which is the term containing Po in the right side and the left side PWV 2 The relationship between them has been found by the present inventors that when the minimum blood pressure value DAP is stable and the compression pressure Pc is in the range of 20 mmHg to 60 mmHg, that is, in the range B shown in FIG. 7, it is a constant value. FIG. 7 is a two-dimensional coordinate with the horizontal axis showing the square value PWV 2 of the pulse wave velocity and the vertical axis showing Ln((DAP - Pc) / Po), and when the compression pressure Pc is changed over the entire range where the compression pressure Pc is less than or equal to the minimum blood pressure value DAP, the pulse wave velocity PWV is measured from the data 2 and the curve when calculating PWV

[0063] and Ln((DAP - Pc) / Po) is shown. And when the compression pressure Pc is sufficiently lower than the minimum blood pressure value DAP of the living body 14, for example, in the range B of 20 mmHg to 60 mmHg, Ln((DAP - Pc) / Po) becomes substantially constant.

[0064] PWV 2 ∝ κ·(DAP - Pc) ··· (14)

[0065] When generalizing the relationship between the pulse wave velocity PWV of formula (14) and the transmural pressure (DAP - Pc), a regression line with slope s and intercept i, that is, the aforementioned formula (1) is obtained. For a predetermined subject to be measured, the minimum blood pressure value DAP R is measured in advance, and then within a pressure range (low - pressure section) lower than the minimum blood pressure value DAP R of the subject to be measured, a plurality of sets of compression pressures Pc and pulse wave velocities PWV measured at different compression pressures are substituted into the same two equations as formula (1). By doing so, i D and s D respectively obtained as the solutions of the two unknowns i and s of these simultaneous equations are taken as the measured calibration values, and the intrinsic relationship shown in formula (2) described later is obtained.

[0066] The inventors measured the minimum blood pressure value DAP R at 8 time points when the blood pressure was widely changed with drugs in the same living body (dog) using an intravascular catheter for blood pressure measurement. At the same time, from a plurality of sets of data of a plurality of different compression pressures Pc within the low - pressure section lower than the minimum blood pressure of these living bodies and a plurality of pulse wave velocities PWV measured under those compression pressures, the transmural pressure (DAP - Pc) was calculated, and experiments were respectively conducted to obtain the regression line between the transmural pressure (DAP - Pc) and the square value PWV 2 of the pulse wave velocity PWV.

[0067] Figures 8 to 15 are diagrams showing the relationship between the transmural pressure (DAP - Pc) and the square value PWV 2 of the pulse wave velocity PWV in two - dimensional coordinates, obtained from a plurality of data obtained using an intravascular catheter for blood pressure measurement at 8 time points (8 experimental Nos. 1 to 8) when the blood pressure was widely changed with drugs in one experimental animal (dog) by the inventors. As shown in Figures 8 to 15, in any of the above - mentioned experimental Nos. 1 to 8, the value of the coefficient of determination R 2 of the regression line y is 0.94 to 0.99, a value close to 1, and a high - quality linear relationship is obtained. That is, it was confirmed that the regression line represented by formula (1) can be stably obtained even when the blood pressure fluctuates greatly.

[0068] Prior to the generation of the specific relationship of Equation (2) by the specific relationship generation unit 92, the blood pressure measurement unit 84 measures the actual maximum blood pressure value SAP R and the actual minimum blood pressure value DAP R of the subject. In this blood pressure measurement, for example, according to the well-known oscillometric method, after the compression pressure Pc of the compression band 12 is increased to a pressure increase target value higher than the maximum blood pressure of the subject by the compression pressure control unit 86, in the pressure reduction process where the compression pressure Pc is gradually reduced, a pulse wave that pulsates in synchronization with the pulse and superimposes on the compression pressure Pc2 of the intermediate expansion bag 24 is detected. Based on the compression pressure Pc corresponding to the inflection point of the envelope (envelope line) connecting the maximum values of the amplitudes of the pulse waves, the maximum blood pressure value SAP R and the minimum blood pressure value DAP R are determined. Also, in this blood pressure measurement, for example, according to the well-known Korotkoff sound method, based on the compression pressure Pc when the vascular sound (Korotkoff sound) generated in synchronization with the pulse detected by the microphone in the above pressure reduction process occurs and the compression pressure Pc when it disappears, the actual maximum blood pressure value SAP R and the minimum blood pressure value DAP R may be determined. The above pulse wave and vascular sound are pulse synchronous waves that occur in synchronization with the pulse of the living body.

[0069] In response to the operation of the blood pressure estimation start operation button 80 shown in FIG. 5, the compression pressure control unit 86 first closes the rapid exhaust valve 52 and the exhaust control valve 54 and opens the first on-off valve E1, the second on-off valve E2, and the third on-off valve E3 for the measurement by the blood pressure measurement unit 84 to obtain the actual blood pressure value AP R of the living body 14 serving as the subject. By operating the air pump 50, the compression pressure Pc of the compression band 12 on the living body 14 is rapidly increased until it reaches a pressure increase target pressure value PCM preset to be sufficiently higher than the maximum blood pressure value SAP of the living body 14, for example, 180 mmHg.

[0070] Next, the compression control unit 86 repeatedly opens the exhaust control valve 54 at a predetermined cycle for a predetermined period, so that the compression pressure Pc of the compression band 12 reaches a measurement end pressure value PCE preset to a pressure sufficiently lower than the minimum blood pressure value DAP of the living body 14, for example, 60 mmHg. The compression pressure Pc of the compression band 12 is gradually decreased in a stepwise manner at a preset pressure reduction rate until the compression pressure Pc of the compression band 12 becomes smaller than the measurement end pressure value PCE, so that a plurality of constant step pressures P1, P2, P3, ··· Px are sequentially maintained. The compression pressure Pc of the compression band 12 controlled in this way compresses the living body 14 with the same compression pressure Pc by the upstream expansion bag 22, the intermediate expansion bag 24, and the downstream expansion bag 26. However, in FIG. 6, the compression pressure Pc of the compression band 12 detected by the fourth pressure sensor is shown.

[0071] Next, in order to obtain the actual first pulse wave velocity PWV1 and the second pulse wave velocity PWV2 as a plurality of pulse wave velocities PWV of the living body 14 to be measured, the compression control unit 86 temporarily maintains a constant first maintenance pressure PcH1 in a first maintenance section (from the time point tk2 to the time point tk3), and after gradually reducing the compression pressure Pc so that a second maintenance section (from the time point tk4 to the time point tk5) that maintains a second maintenance pressure PcH2 lower than the first maintenance pressure PcH1 is sequentially formed, the pressure in the upstream expansion bag 22, the intermediate expansion bag 24, and the downstream expansion bag 26 is exhausted to the atmospheric pressure using the rapid exhaust valve 52. The first maintenance pressure PcH1 and the second maintenance pressure PcH2 are preset values within a range of a pressure sufficiently lower than the minimum blood pressure value DAP of the living body 14 as the subject, for example, within the range of 20 to 60 mmHg.

[0072] Then, after the specific relationships shown in, for example, Equation (2) and Equation (4) described later are generated by the specific relationship generation unit 92 described later, the compression pressure control unit 86 estimates the estimated maximum blood pressure value SAPe and the estimated minimum blood pressure value DAPe of the living body 14 from Equation (2) and Equation (4). In response to a blood pressure estimation start command (at time tm1) that is repeatedly issued by the electronic control device 70 at a predetermined blood pressure estimation cycle, for example, a cycle of several tens of seconds to several minutes, the compression pressure Pc is controlled to maintain a constant monitor pressure PcHm set in advance within a range sufficiently lower than the minimum blood pressure value DAP of the living body 14, for example, within the range of 20 to 60 mmHg, in the monitor pressure maintenance section (from time tm2 to time tm3).

[0073] When the monitor pressure maintenance section (from time tm2 to time tm3) ends, the compression pressure control unit 86 uses the rapid exhaust valve 52 to exhaust the pressures in the upstream expansion bag 22, the intermediate expansion bag 24, and the downstream expansion bag 26 to atmospheric pressure respectively. The compression pressure control unit 86 repeatedly executes such a compression pressure control cycle for blood pressure estimation in response to the repeatedly issued blood pressure estimation start command (at time tm1). The monitor pressure PcHm may be the same as the first maintenance pressure PcH1 maintained in the first maintenance section (from time tk2 to time tk3), or the second maintenance pressure PcH2 maintained in the second maintenance section (from time tk4 to time tk5), or may be different maintenance pressures.

[0074] The pulse wave extraction unit 88 extracts and stores a pair of pulse waves MW11 and pulse wave MW13 obtained by passing through a low-pass filter for pulse wave discrimination that discriminates signals in a wavelength band of 0 Hz to less than 25 Hz from the output signal indicating the compression pressure PcH1 in the upstream expansion bag 22 from the first pressure sensor T1 and the output signal indicating the compression pressure PcH1 of the downstream expansion bag 26 from the third pressure sensor T3 under the first maintenance pressure PcH1 in the first maintenance section set in advance within a range sufficiently lower than the minimum blood pressure value DAP of the living body 14, for example, within the range of 20 to 60 mmHg.

[0075] Further, the pulse wave extraction unit 88 extracts and stores a pair of pulse waves MW21 and MW23 respectively through the low-pass filter for pulse wave discrimination from an output signal indicating the compression pressure PcH2 in the upstream expansion bag 22 from the first pressure sensor T1 and an output signal indicating the compression pressure PcH2 in the downstream expansion bag 26 from the third pressure sensor T3 under the second holding pressure PcH2 in the second holding section set to a value lower than the first holding pressure PcH1.

[0076] The pair of pulse waves MW11 and MW13 and the pair of pulse waves MW21 and MW23 are pressure vibration waves generated in synchronization with the heartbeat superimposed on the compression pressure PcH1 and the compression pressure PcH2. The pulse wave extraction unit 88 stores the pulse waves MW11 and MW13, and the pulse waves MW21 and MW23, and the compression pressure Pc at the time when they are generated in association with each other. Further, as described above, since the pulse waves MW11 and MW13, and the pulse waves MW21 and MW23 are obtained by the low-pass filter processing for pulse wave acquisition that discriminates signals in the wavelength band of 0 Hz to less than 25 Hz, the magnitudes of the pulse waves MW11 and MW13, and the pulse waves MW21 and MW23 are represented in the same unit mmHg as the compression pressure Pc, for example, as shown in FIG. 16 described later.

[0077] The pulse wave propagation speed calculation unit 90 calculates the time difference (propagation time) Δt113 between the pair of pulse waves MW11 and MW13 obtained respectively in a plurality of sections in a region where the compression pressure Pc of the compression zone 12 is sufficiently lower than the minimum blood pressure value DAP of the living body 14, for example, in the first holding section (time point tk2 to time point tk3) and the second holding section (time point tk4 to time point tk5), and the time difference (propagation time) Δt213 between the pair of pulse waves MW21 and MW23. Next, the pulse wave propagation speed calculation unit 90 calculates and stores the pulse wave propagation speed PWV1 (= L13 / Δt113) in the first holding section and the pulse wave propagation speed PWV2 (= L13 / Δt213) in the second holding section based on the time differences Δt113 and Δt213 and the distance L13 between the upstream expansion bag 22 and the downstream expansion bag 26 which is the propagation distance.

[0078] FIG. 16 is a diagram in which the amplitude of the pulse wave MW and its first differential waveform dMW / dt are superimposed in phase on a common time axis, showing that the zero-crossing point ZX1 from negative to positive of the first differential waveform dMW / dt of the pulse wave is at the same time as the minimum part (local minimum point) MWLMP of the pulse wave MW, the zero-crossing point ZX2 from positive to negative of the first differential waveform dMW / dt of the pulse wave is at the same time as the maximum part (maximum peak point, i.e., local maximum point) MWLXP of the pulse wave MW, and the zero-crossing point ZX3 from negative to positive of the first differential waveform dMW / dt of the pulse wave is at the same time as the notch part (notch point, i.e., dicrotic notch point) MWLNP after the maximum part MWLXP of the pulse wave MW.

[0079] The pulse wave propagation velocity calculation unit 90 calculates, as the time differences Δt113 and Δt213, the time difference Δt113 between the minimum parts of a pair of pulse waves MW11 and MW13 in order to generate the equation (2) which is an intrinsic relationship for estimating the estimated minimum blood pressure value DAPe. D and the time difference Δt213 between the minimum parts of a pair of pulse waves MW21 and MW23. D The minimum parts of the pulse waves MW11 and MW13 and the minimum parts of the pulse waves MW21 and MW23 are, for example, the rising points of the pulse waves MW11 and MW13 or the zero-crossing points from negative to positive of the first differential waves of the pulse waves MW11 and MW13, and the rising points of the pulse waves MW21 and MW23 or the zero-crossing points from negative to positive of the first differential waves of the pulse waves MW21 and MW23. Then, the pulse wave propagation velocity calculation unit 90 calculates the pulse wave propagation velocity PWV1 D (=L13 / Δt113 D ) in the first maintenance section and the pulse wave propagation velocity PWV2 D (=L13 / Δt213 D ) in the second maintenance section.

[0080] The pulse wave propagation velocity calculation unit 90 calculates, as the time differences Δt113 and Δt213 used for generating the equation (4) which is an intrinsic relationship for estimating the estimated maximum blood pressure value SAPe, the time difference Δt113 between the maximum parts of a pair of pulse waves MW11 and MW13. SCalculate the time difference Δt213 between the maximum positions of a pair of pulse waves MW21 and MW23. S The maximum positions of the pulse waves MW11 and MW13 and the maximum positions of the pulse waves MW21 and MW23 are, for example, the maximum peak points of the pulse waves MW11 and MW13 or the zero-crossing points from positive to negative of the first derivative waves of the pulse waves MW11 and MW13, and the maximum peak points of the pulse waves MW21 and MW23 or the zero-crossing points from positive to negative of the first derivative waves of the pulse waves MW21 and MW23. The pulse wave propagation speed calculation unit 90 is the pulse wave propagation speed PWV1 in the first maintenance interval for use in the estimation of the estimated maximum blood pressure value SAPe. S (=L13 / Δt113 S ) and the pulse wave propagation speed PWV2 in the second maintenance interval S (=L13 / Δt213 S ) are calculated respectively.

[0081] In addition, in FIG. 16, it was shown that the minimum position MWLMP, the maximum position MWLXP, the notch position MWLNP, etc. of the pulse wave MW are obtained using the first derivative waveform dMW / dt of the pulse wave MW. However, as shown in FIG. 17, they can also be obtained using the pulse wave MW and its second derivative waveform d 2 MW / dt 2 . FIG. 17 is a diagram showing the pulse wave MW and its second derivative waveform d 2 MW / dt 2 on the same time axis in the same phase, showing the correspondence between the minimum position MWLMP and the notch position MWLNP of the pulse wave MW and the vertices ZT1 and ZT3 of the second derivative waveform of the pulse wave MW. In FIG. 17, the first vertex (peak point) ZT1 within the period of the second derivative waveform d 2 MW / dt 2 is at the same time as the minimum position MWLMP which is the rising time point of the pulse wave MW. Also, the vertex ZT3 that takes the maximum value on the second derivative waveform after the time point ZT2 which is the same time as the maximum position MWLXP of the pulse wave MW is at the same time as the notch position MWLNP.

[0082] When using the second derivative waveform shown in FIG. 17, the pulse wave velocity calculation unit 90, for example, uses the time differences Δt113 and Δt213 used to generate the intrinsic relationship of Equation (2) for estimating the estimated minimum blood pressure value DAPe as the time difference Δt113 between the peaks (peak points) ZT1 of the second derivative waveforms of a pair of pulse waves MW11 and MW13 D , and the time difference Δt213 between the peaks (peak points) ZT1 of the second derivative waveforms of a pair of pulse waves MW21 and MW23 D are calculated respectively, and the pulse wave velocity PWV1 D (=L13 / Δt113 D ), and the pulse wave velocity PWV2 D (=L13 / Δt213 D ) in the second maintenance interval are calculated respectively. When generating the intrinsic relationship of Equation (6) for estimating the estimated notch blood pressure value DNAPe, the pulse wave velocity calculation unit 90 similarly obtains the time differences Δt113 DN and Δt213 DN , the pulse wave velocity PWV1 DN , and the pulse wave velocity PWV2 DN from the second derivative waveform

[0083] After the intrinsic relationships of Equation (2) and Equation (4) are generated, the pulse wave velocity calculation unit 90 calculates, in the monitor pressure maintenance interval (from time point tm2 to time point tm3) of a constant monitor pressure PcHm formed for each blood pressure estimation start command (at time point tm1), the time difference Δt113 between the minimum parts of a pair of pulse waves MW11 and MW13 D and the Δt113 between the maximum parts S , and calculates the pulse wave velocity PWV D and Δt113 S from these time differences Δt113 D used for estimating the estimated minimum blood pressure value DAPe of Equation (2) and the pulse wave velocity PWV S used for estimating the estimated maximum blood pressure value SAPe of Equation (4) respectively

[0084] The intrinsic relationship generation unit 92 measures the actual maximum blood pressure value SAP R , and the actual minimum blood pressure value DAP Rand the actual compression pressures in the low pressure section, namely compression pressures PcH1 and PcH2, and the actual pulse wave velocity PWV1 obtained under the compression pressures PcH1 and PcH2 S pulse wave velocity PWV2 S or PWV1 D PWV2 D Generate and store the intrinsic relationships shown in equations (2) and (4) respectively between them. This intrinsic relationship is repeatedly used in subsequent monitoring cycles.

[0085] The intrinsic relationship generation unit 92 substitutes the minimum blood pressure value DAP actually measured by the blood pressure measurement unit 84 into two equations respectively shown by equation (1) indicating a linear relationship, and for each of a plurality of compression pressures (the first maintenance pressure in the first maintenance section) PcH1 and compression pressures (the second maintenance pressure in the second maintenance section) PcH2 within the low pressure section lower than the minimum blood pressure value DAP of the living body 14 being measured, the propagation time Δt113 between the minimum parts of a pair of pulse waves obtained respectively R and the time difference Δt213 D Based on this, when the actual pulse wave velocities are PWV1 D and PWV2 D are substituted respectively, i D and s D obtained respectively as the solutions of the two unknowns i and s of the two equations are taken as the actual measurement calibration values, thereby generating the intrinsic relationship for estimating the minimum blood pressure represented by equation (2) for the living body 14 being measured. D DAPe = PWV

[0086] DAPe = PWV D 2 / s D -i D / s D +Pc ··· (2)

[0087] The intrinsic relationship generation unit 92 substitutes the maximum blood pressure value SAP actually measured by the blood pressure measurement unit 84 into two equations respectively shown by equation (3) indicating a linear relationship RSubstitute each into SAP, and for each of a plurality of compression pressures PcH1 (the first holding pressure in the first holding interval) and compression pressure PcH2 (the second holding pressure in the second holding interval) within the low pressure interval lower than the minimum blood pressure value DAP of the living body 14 being the subject to be measured, the propagation time Δt113 between the maximum sites of a pair of pulse waves obtained respectively S and time difference Δt213 S Based on this, the actual pulse wave velocity is PWV1 S and PWV2 S When substituting each, as the solutions of the two unknowns i and s in the two equations, the obtained i S and s S Taking them as the actually measured calibration values, the characteristic relationship for estimating the maximum blood pressure represented by equation (4) is generated for the living body 14 being the subject to be measured.

[0088] SAPe = PWV S 2 / s S -i S / s S +Pc ··· (4)

[0089] The blood pressure estimation unit 94 includes a minimum blood pressure estimation unit 96 and a maximum blood pressure estimation unit 98. After the characteristic relationship shown in equation (2) is obtained, the minimum blood pressure estimation unit 96, for each blood pressure estimation cycle, the actual compression pressure PcH1 in the low pressure interval sufficiently lower than the minimum blood pressure value DAP of the living body 14 and the actual pulse wave velocity PWV1 obtained under the compression pressure PcH1 D , or the actual compression pressure PcH2 and the actual pulse wave velocity PWV2 obtained under the compression pressure PcH2 D are applied to the characteristic relationship shown in equation (2) to estimate the estimated minimum blood pressure value DAPe of the living body 14 being the subject to be measured. Regarding the compression pressure control, only one of the first holding interval and the second holding interval may be provided. Also, the estimated minimum blood pressure value obtained by applying the compression pressure PcH1 and the pulse wave velocity PWV1 D to the characteristic relationship shown in equation (2), and the compression pressure PcH2 and the pulse wave velocity PWV2 D The average value of the minimum blood pressure values estimated by applying to the characteristic relationship shown in equation (2) may be estimated as the estimated minimum blood pressure value DAPe.

[0090] After the specific relationship shown in Equation (4) is obtained, the maximum blood pressure estimation unit 98, for each blood pressure estimation cycle, the actual compression pressure PcH1 in a low pressure section that is sufficiently lower than the minimum blood pressure value DAP of the living body 14 and the actual pulse wave velocity PWV1 obtained under the compression pressure PcH1 S , or the actual compression pressure PcH2 and the actual pulse wave velocity PWV2 obtained under the compression pressure PcH2 S are applied to the specific relationship shown in Equation (4) to estimate the estimated maximum blood pressure value SAPe of the living body 14, which is the subject to be measured.

[0091] FIG. 18 shows the minimum blood pressure value DAP actually measured at 8 time points when the inventors widely changed the blood pressure of one experimental animal (dog) with a drug, using a blood pressure measurement intravascular catheter R and the relationship with the estimated minimum blood pressure value DAPe estimated by the minimum blood pressure estimation unit 96 using the specific relational expression (Equation (2)) obtained as described above using the blood pressure monitoring device of this embodiment. FIG. 18 is a two-dimensional coordinate with the horizontal axis showing the estimated minimum blood pressure value DAPe and the vertical axis showing the actually measured minimum blood pressure value DAP R . The regression line of the 8 plotted points shown there is y = 0.6648x + 32.154, and the coefficient of determination R 2 is R 2 = 0.95. Therefore, it was confirmed that there is a high correlation between the estimated minimum blood pressure value DAPe and the actually measured minimum blood pressure value DAP R .

[0092] FIG. 19 is a flowchart for explaining the main part of the control operation of the electronic control device 70. When the blood pressure estimation start operation button 80 is operated to be on, in step S1 corresponding to the compression pressure control unit 86 (hereinafter, "step" is omitted), the compression pressure Pc of the compression band 12 is increased. Specifically, as shown in FIG. 6, the rapid exhaust valve 52 is closed, and the air pump 50 is put into an operating state, and the pressure in the main pipe 56 and the upstream expansion bag 22, the intermediate expansion bag 24, and the downstream expansion bag 26 communicated therewith is rapidly increased by the compressed air pumped from the air pump 50. Then, the compression of the upper arm 16 by the compression band 12 is started.

[0093] Next, in S2 corresponding to the compression pressure control unit 86, based on the output signal of the fourth pressure sensor T4 indicating the compression pressure Pc of the compression band 12, it is determined whether or not the compression pressure Pc is equal to or higher than a preset pressure increase target pressure value PCM (for example, 180 mmHg). Before the time t2 in FIG. 6, the determination in S2 is negative, and S1 and below in FIG. 12 are repeatedly executed.

[0094] When the compression pressure Pc reaches the pressure increase target pressure value PCM and the determination in S2 is affirmative, in S3 corresponding to the compression pressure control unit 86, the operation of 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 operated so as to slowly exhaust in a step-down manner in which the compression pressure Pc of the upstream expansion bag 22 and the compression band 12 sequentially forms preset step pressures P1, P2, P3, ··· Px, for example, at 3 to 5 mmHg / sec. When holding the 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 closed. The time t2 in FIG. 6 is the start time of the slow exhaust, and the time between t3 and t4 is the time during which the compression pressure Pc of the compression band 12 is held for a predetermined time, for example, two beats, at the step pressure P1.

[0095] Next, in S4, while the compression pressures P1, P2, and P3 are each held for a predetermined time, low-pass filter processing for discriminating signals in a wavelength band of, for example, 0 Hz to less than 25 Hz is performed on the output signals from the first pressure sensor T1, the second pressure sensor T2, and the third pressure sensor T3, respectively, whereby pulse wave signals SM1, SM2, and SM3 indicating pulse waves from the upstream expansion bag 22, the intermediate expansion bag 24, and the downstream expansion bag 26 are extracted. Further, low-pass filter processing for a wavelength band of less than several Hz, for example, is performed on the output signal from the fourth pressure sensor T4, whereby the compression pressure Pc of the compression band 12 from which the AC component has been removed is extracted and stored.

[0096] In S5 corresponding to the compression pressure control unit 86, it is determined whether or not the compression pressure Pc is equal to or lower than a preset measurement end pressure value PCE (for example, 60 mmHg). If the determination in this S5 is negative, that is, at a point in time before time t11 in FIG. 6, the determination in S5 is negative and S3 and subsequent steps are repeatedly executed.

[0097] When the determination in S5 is affirmative, in S6 and S7 corresponding to the blood pressure measurement unit 84, a pair of compression pressures Pc corresponding to the inflection points of the envelope connecting the peak values of the pulse wave signal SM2 (intermediate pulse wave) sequentially obtained in the process of reducing the compression pressure Pc of the compression band 12 from a preset pressure increase target pressure value PCM that is sufficiently higher than the maximum blood pressure value SAP, that is, the maximum points and minimum points of the first derivative waveform of the envelope, are respectively the actual maximum blood pressure value SAP R and the minimum blood pressure value DAP R of the living body 14 serving as the subject to be measured. These actual maximum blood pressure value SAP R and the minimum blood pressure value DAP R are used for the generation of the specific relationships, that is, equations (2) and (4), for estimating the blood pressure of the living body 14 serving as the subject to be measured.

[0098] Next, in S8 corresponding to the compression pressure control unit 86, control is performed such that the compression pressure Pc becomes a first maintenance section (time point tk2 to time point tk3) for temporarily maintaining a constant first maintenance pressure PcH1.

[0099] Subsequently, in S9 corresponding to the pulse wave extraction unit 88, from the output signal indicating the compression pressure PcH1 in the upstream expansion bag 22 from the first pressure sensor T1 and the output signal indicating the compression pressure PcH1 of the downstream expansion bag 26 from the third pressure sensor T3 under the first holding pressure PcH1, a pair of pulse waves MW11 and pulse wave MW13 are respectively extracted through a band-pass filter for pulse wave discrimination and stored.

[0100] Next, in S10 corresponding to the pulse wave propagation velocity calculation unit 90, the time difference Δt113 between the minimum parts of a pair of pulse waves MW11 and pulse wave MW13 D is calculated, and from the time difference Δt113 D the pulse wave propagation velocity PWV1 in the first holding section D (=L13 / Δt113 D ) is calculated. At the same time, also in S10, the time difference Δt113 between the maximum parts of a pair of pulse waves MW11 and pulse wave MW13 S is calculated, and from the time difference Δt113 S the pulse wave propagation velocity PWV1 in the first holding section S (=L13 / Δt113 S ) is calculated.

[0101] Then, in S11 corresponding to the compression pressure control unit 86, it is controlled so as to be in a second holding section (from the time point tk4 to the time point tk5) that maintains the compression pressure Pc at a second holding pressure PcH2 lower than the first holding pressure PcH1.

[0102] Subsequently, in S12 corresponding to the pulse wave extraction unit 88, from the output signal indicating the compression pressure PcH2 in the upstream expansion bag 22 from the first pressure sensor T1 and the output signal indicating the compression pressure PcH2 of the downstream expansion bag 26 from the third pressure sensor T3 under the second holding pressure PcH2, a pair of pulse waves MW21 and pulse wave MW23 are respectively extracted through a band-pass filter for pulse wave discrimination and stored.

[0103] Next, in S13 corresponding to the pulse wave propagation velocity calculation unit 90, the time difference Δt213 between the minimum parts of a pair of pulse waves MW21 and pulse wave MW23 D is calculated, and the time difference Δt213D From this, the pulse wave velocity PWV2 in the second maintenance interval D (= L13 / Δt213 D ) is calculated. At the same time, also at S13, the time difference Δt213 between the maximum positions of a pair of pulse waves MW21 and MW23 S is calculated, and from this time difference Δt213 S the pulse wave velocity PWV2 in the second maintenance interval S (= L13 / Δt213 S ) is calculated.

[0104] At S14 corresponding to the characteristic relationship generation unit 92, the minimum blood pressure value DAP measured at S6 is substituted into two equations respectively represented by the linear relationship (1) equation as DAP, and the propagation time Δt113 between the minimum positions of a pair of pulse waves obtained for each of the first maintenance pressure PcH1 in the first maintenance interval and the second maintenance pressure PcH2 in the second maintenance interval R and the time difference Δt213 D Based on this, when the actual pulse wave velocities based on PWV1 D and PWV2 D are respectively substituted, i D and s D obtained respectively as the solutions of the two unknowns i and s of the two equations are used as the measured calibration values, and the characteristic relationship for estimating the minimum blood pressure represented by the (2) equation is generated for the living body 14 which is the subject to be measured. D

[0105] Also at S14, the maximum blood pressure value SAP measured at S7 is substituted into two equations respectively represented by the linear relationship (3) equation as SAP, and the propagation time Δt113 between the minimum positions of a pair of pulse waves obtained for each of the first maintenance pressure PcH1 in the first maintenance interval and the second maintenance pressure PcH2 in the second maintenance interval R and the time difference Δt213 S Based on this, when the actual pulse wave velocities PWV1 S and the pulse wave velocity PWV2 S are respectively substituted as PWV, i S and s S obtained respectively as the solutions of the two unknowns i and s of the two equations are obtained​S By using the actually measured calibration value, the specific relationship for systolic blood pressure estimation represented by equation (4) is generated for the living body 14, which is the subject to be measured.

[0106] In subsequent S15, the rapid exhaust valve 52 is operated so that the pressures in the upstream expansion bag 22, the intermediate expansion bag 24, and the downstream expansion bag 26 are each exhausted to atmospheric pressure.

[0107] In S16, it is determined whether a blood pressure estimation start command is issued at a predetermined blood pressure estimation cycle, for example, a cycle of about several tens of seconds to several minutes. If the determination in this S16 is negative, the system waits, but if it is positive, the blood pressure estimation routine from S17 and below is executed.

[0108] In S17 corresponding to the compression control unit 86, the compression pressure Pc is increased to a compression pressure between 20 and 60 mmHg, which is lower than the diastolic blood pressure value DAP of the living body 14, for example, the monitor pressure PcHm, and a monitor pressure maintenance section (from the time point tm2 to the time point tm3) for maintaining the monitor pressure PcHm is formed and controlled.

[0109] Subsequently, in S18 corresponding to the pulse wave extraction unit 88, from the output signal indicating the compression pressure PcHm in the upstream expansion bag 22 from the first pressure sensor T1 and the output signal indicating the compression pressure PcHm of the downstream expansion bag 26 from the third pressure sensor T3 under the monitor pressure PcHm in the monitor pressure maintenance section, a pair of pulse waves MWm1 and pulse wave MWm3 are respectively extracted through a band - pass filter for pulse wave discrimination and stored.

[0110] Next, in S19 corresponding to the pulse wave propagation velocity calculation unit 90, the time difference Δtm13 D between the minimum parts of the pair of pulse waves MWm1 and pulse wave MWm3 is calculated, and from the time difference Δtm13 D the pulse wave propagation velocity PWVm D (=L13 / Δtm13 D ) is calculated in the monitor pressure maintenance section. Also, the time difference Δtm13 S between the maximum parts of the pair of pulse waves MWm1 and pulse wave MWm3 is calculated, and the time difference Δtm13S From this, the pulse wave velocity PWVm in the monitor pressure maintenance section S (=L13 / Δtm13 S ) is calculated.

[0111] Then, in S20 corresponding to the minimum blood pressure estimation unit 96, the monitor pressure PcHm and the pulse wave velocity PWVm are applied to equation (2) showing the intrinsic relationship of the living body 14 to be measured, whereby the estimated minimum blood pressure value DAPe is calculated. Further, in S21 corresponding to the maximum blood pressure estimation unit 98, the monitor pressure PcHm and the pulse wave velocity PWVm are applied to equation (4) showing the intrinsic relationship of the living body 14 to be measured, whereby the estimated maximum blood pressure value SAPe is calculated. D S

[0112] In the subsequent 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. In the subsequent S23, the pressures in the upstream expansion bag 22, the intermediate expansion bag 24, and the downstream expansion bag 26 are each depressurized to atmospheric pressure. Then, in S24, it is determined whether there is a stop (off) operation by the blood pressure estimation start operation button 80. As long as the determination in S24 is negative, the blood pressure estimation routine from S16 and below is repeated, but when the determination in S24 is positive, the blood pressure monitoring routine is terminated.

[0113] As described above, the intrinsic relationship generation unit 92 determines the square value PWV of the plurality of pulse wave velocities respectively detected under a plurality of compression pressures in the low pressure section lower than the minimum blood pressure value DAP of the living body 14 by the compression band 12, and the actual blood pressure value AP of the living body 14, the regression line shown in the pre-stored linear relationship ((1) equation, (3) equation) between the wall pressure (AP - Pc) of the artery 18, 2 (DAP R (DAP R , SAP R ), and the pulse wave velocity PWV1 (PWV1 D , PWV1 S ) at the actual compression pressure PcH1 lower than the minimum blood pressure value DAP of the living body 14 and the pulse wave velocity PWV2 (PWV2 D , PWV2 SBy applying the following, the estimated blood pressure value APe(DAPe, SAPe) and the actual compression pressures PcH1, PcH2 and the actual pulse wave velocity PWV1(PWV1 D , PWV1 S ) and the pulse wave velocity PWV2(PWV2 D , PWV2 S ) generate the inherent relationship ((2) formula, (4) formula) of the living body 14. The blood pressure estimation unit 94 applies the actual compression pressure PcHm and the actual pulse wave velocity PWVm(PWVm D , PWVm S ) to the inherent relationship ((2) formula, (4) formula) to estimate the estimated blood pressure value APe(SAPe, DAPe) of the living body 14.

[0114] As described above, according to the blood pressure monitoring device 10 of the present embodiment, it has a plurality of inflatable bags 22, 24, 26 that form independent air chambers arranged in the width direction, and is wound around the upper arm (compressed part) 16 of the living body (subject) 14 to compress the artery 18 of the living body 14. A blood pressure monitoring device 10 that repeatedly estimates the estimated blood pressure value APe of the living body 14, and the square value PWV of the pulse wave velocity respectively detected under a plurality of compression pressures Pc of the compression band 12 in a low pressure section lower than the minimum blood pressure value DAP of the living body 14 2 And a linear relationship storage unit 82 that stores a pre-stored linear relationship between the arterial 18 wall pressure, which is the pressure difference between the blood pressure value AP in the artery 18 and the compression pressure Pc of the compression band 12, and the actual blood pressure value AP of the living body 14 based on the pulse synchronous wave from the artery 18 obtained during the pressure reduction process after compressing the upper arm 16 of the living body 14 with a compression pressure Pc higher than the maximum blood pressure value SAP of the living body 14 R A blood pressure measurement unit 84 that measures, and for the living body 14, the actual blood pressure value AP R And the actual blood pressure value AP of the living body 14 by applying the actual blood pressure value AP and the plurality of actual compression pressures PcH1 and PcH2 in the low pressure section and the actual pulse wave velocities PWV1 and PWV2 based on the propagation time between the pulse waves obtained under the actual compression pressures PcH1 and PcH2 to the linear relationship RA characteristic relationship generation unit 92 that generates a characteristic relationship for the living body 14 between the actual compression pressures PcH1 and PcH2 and the actual pulse wave propagation velocities PWV1 and PWV2, and for the living body 14, the actual compression pressure PcHm in the low pressure section and the actual pulse wave propagation velocity PWVm obtained at the actual compression pressure PcHm are applied to the characteristic relationship for the living body 14, thereby estimating an estimated blood pressure value APe, including a blood pressure estimation unit 94. Thereby, the actual maximum blood pressure value SAP of the living body 14 by the blood pressure measurement unit 84 R and the actual minimum blood pressure value DAP R Except when measuring, the compression pressure Pc by the compression band 12 is set to a value lower than the minimum blood pressure value DAP of the living body 14, and the application of the compression pressure PcHm can be performed in a short time (several seconds) and blood pressure measurement is possible at short time intervals. Therefore, the burden on the living body 14 can be reduced, and continuous estimation of blood pressure fluctuations in a shorter time becomes possible.

[0115] Also, according to the blood pressure monitoring device 10 of the present embodiment, in the characteristic relationship generation unit 92, the actual minimum blood pressure value DAP of the living body 14 R And the time difference Δt113 between the actual plurality of compression pressures (first maintenance pressure PcH1 and second maintenance pressure PcH2) and the minimum parts of the pulse waves respectively obtained at the actual plurality of compression pressures D And Δt213 D Based on the pulse wave propagation velocity (PWV1 D And PWV2 D ), the characteristic relationship formula (2) of the living body 14 between the estimated minimum blood pressure value DAPe, the plurality of compression pressures (first maintenance pressure PcH1 and second maintenance pressure PcH2), and the pulse wave propagation velocity (PWV1 D And PWV2 D ) is generated. Therefore, the minimum blood pressure estimation unit 96 uses the actual compression pressure (for example, the first maintenance pressure PcH1) obtained in the low pressure section lower than the minimum blood pressure value DAP and the time difference Δt113 between the minimum parts of the pulse waves obtained under the actual compression pressure D Based on the pulse wave propagation velocity PWV1 D By applying to the characteristic relationship of the formula (2) generated by the characteristic relationship generation unit 92, the estimated minimum blood pressure value DAPe of the living body 14 can be easily estimated.

[0116] Also, according to the blood pressure monitoring device 10 of the present embodiment, the time difference (propagation time) Δt113 between the minimum parts of the pair of pulse waves MW11 and MW13 D is the propagation time between the rising points of the pulse waves MW11 and MW13 respectively. In this way, the time difference Δt113 between the minimum parts of the pair of pulse waves MW11 and MW13 D can be easily obtained, and the blood pressure estimation accuracy is improved.

[0117] Also, according to the blood pressure monitoring device 10 of the present embodiment, the blood pressure estimation unit 94 includes a minimum blood pressure estimation unit 96 that estimates the estimated minimum blood pressure value DAPe of the living body 14 by sequentially applying a plurality of actual compression pressures PcH1 or PcH2 and the actual pulse wave propagation velocity PWV1 obtained under these actual compression pressures PcH1 or PcH2 in a low pressure section lower than the minimum blood pressure value DAP of the living body 14 to the intrinsic relationship of equation (2). Thereby, 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. D or PWV2 D to the intrinsic relationship of equation (2). Thereby, 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.

[0118] Also, according to the blood pressure monitoring device 10 of the present embodiment, in the intrinsic relationship generation unit 92, the actual maximum blood pressure value SAP of the living body 14, a plurality of actual compression pressures (the first maintenance pressure PcH1 and the second maintenance pressure PcH2), and the time difference Δt113 between the maximum parts of the pulse waves obtained at the plurality of actual compression pressures S and Δt213 S Based on the pulse wave propagation velocities (PWV1 S and PWV2 S ), the intrinsic relational expression (4) of the living body 14 between the estimated maximum blood pressure value SAPe, the compression pressure, and the pulse wave propagation velocity is generated. Therefore, the maximum blood pressure estimation unit 98 applies the pulse wave propagation velocity PWV1 based on the time difference Δt113 between the maximum parts of the actual compression pressure (for example, the first maintenance pressure PcH1) obtained in the low pressure section lower than the minimum blood pressure value DAP and the pulse waves obtained at the actual compression pressure to the (4) generated by the intrinsic relationship generation unit 92. By applying the formula, the estimated maximum blood pressure value SAPe of the living body 14 can be estimated. S Based on the pulse wave propagation velocity PWV1 S to the (4) generated by the intrinsic relationship generation unit 92. By applying the formula, the estimated maximum blood pressure value SAPe of the living body 14 can be estimated.

[0119] Also, according to the blood pressure monitoring device 10 of the present embodiment, the time difference (propagation time) Δt113 between the maximum positions of the pair of pulse waves MW11 and MW13 S is the propagation time between the maximum points of the pulse waves MW11 and MW13. In this way, the propagation time between the maximum positions of the pulse waves can be easily obtained, and the blood pressure estimation accuracy can be improved.

[0120] Also, according to the blood pressure monitoring device 10 of the present embodiment, the blood pressure estimation unit 94 includes a maximum blood pressure estimation unit 98 that estimates the estimated maximum blood pressure value SAPe of the living body 14 by sequentially applying, for the living body 14 as the subject to be measured, the actual compression pressure and the actual pulse wave propagation speed obtained for each of the actual compression pressures in a low pressure section lower than the minimum blood pressure value DAP of the living body 14 (PcH1 or actual compression pressure PcH2), and the actual pulse wave propagation speed PWV1 S or PWV2 S and the like to the specific relationship of equation (4). Thereby, the burden on the living body 14 can be reduced, and the estimated maximum blood pressure value SAPe of the living body 14 can be easily estimated.

[0121] Further, according to the blood pressure monitoring device 10 of the present embodiment, a plurality of compression pressures (first maintenance pressure PcH1 and second maintenance pressure PcH2) within a low pressure range lower than the minimum blood pressure value DAP of the living body 14 are temporarily maintained at a constant value within a low pressure range lower than the minimum blood pressure value DAP of the living body 14. A compression pressure control unit 86 that gradually reduces the pressure to form a plurality of sections (first maintenance section and second maintenance section), and a plurality of pressure vibrations that occur synchronously with the pulse within a plurality of expansion bags (upstream expansion bag 22 and downstream expansion bag 26) under the compression pressure in the plurality of sections. A pulse wave extraction unit 88 that extracts a pulse wave, and a pulse wave propagation speed calculation unit 90 that calculates the pulse wave propagation speed based on the time difference of the pulse waves obtained in the plurality of sections and the distance (L13) between the plurality of expansion bags. Thereby, the pulse waves obtained in the sections (first maintenance section and second maintenance section) where the compression pressure is maintained at a constant value are waveforms without distortion due to the influence of fluctuations in the compression pressure. Therefore, the pulse wave propagation speed PWV can be accurately obtained, and the intrinsic relational expressions (2) and (4) of the living body 14 can be accurately calculated.

[0122] Further, according to the blood pressure monitoring device 10 of the present embodiment, the compression band 12 is wound around the compressed part of the living body, and has independent upstream expansion bags 22, intermediate expansion bags 24, and downstream expansion bags 26 arranged in the width direction to compress the compressed parts of the living body 14 respectively. The upstream expansion bag 22, the intermediate expansion bag 24, and the downstream expansion bag 26 compress the artery 18 in the compressed part with the same compression pressure respectively. Thereby, there is an advantage that blood pressure measurement using compression on the limbs of the living body 14 and detection of the pulse wave propagation speed PWV can be performed simultaneously.

Embodiment

[0123] Next, a blood pressure monitoring device 110 according to another embodiment of the present invention will be described. In the following, parts common to the foregoing embodiments are denoted by the same reference numerals and description thereof is omitted.

[0124] In the foregoing embodiment, in order to estimate the estimated maximum blood pressure value SAPe of the living body 14, in the intrinsic relationship generation unit 92, the actual maximum blood pressure value SAP of the living body 14 Rand the actual plurality of compression pressures (the first holding pressure PcH1 and the second holding pressure PcH2) and the time difference Δt113 between the maximum parts of the pulse waves obtained under the actual plurality of compression pressures S and Δt213 S Based on the pulse wave velocity (PWV1 S and PWV2 S ), the specific relational expression (Equation (4)) between the estimated maximum blood pressure value SAPe, the compression pressure, and the pulse wave velocity for the pre-measured person is generated. In the maximum blood pressure estimation unit 98, the actual compression pressure (for example, the first holding pressure PcH1) obtained in the low pressure section lower than the minimum blood pressure value DAP and the time difference Δt113 between the maximum parts of the pulse waves obtained at the actual compression pressure S Based on the pulse wave velocity PWV1 S is applied to Equation (4) generated by the specific relationship generation unit 92, and the estimated maximum blood pressure value SAPe of the living body 14 is estimated. On the other hand, in this embodiment, the estimated notch blood pressure value DNAPe, which is the compression pressure at the time of occurrence of the notch site locally formed after the maximum site, is estimated using the same estimation method as described above, and the estimated maximum blood pressure value SAPe is estimated from the estimated notch blood pressure value DNAPe, which is different

[0125] FIG. 20 is a functional block diagram for explaining the control function of the electronic control device 170 in this embodiment. The linear relationship storage unit 182, similar to the linear relationship storage unit 82, in the low pressure section lower than the minimum blood pressure value DAP of the living body 14, the square value PWV of the plurality of pulse wave velocities PWV respectively detected under the plurality of compression pressures Pc of the compression band 12 2In addition to the linear relationships of the memorized equations (1) and (3) with the transmural pressure (AP - Pc) of the artery 18, which is the pressure difference between the blood pressure value AP in the artery 18 and the compression pressure Pc, for the notch blood pressure value DNAP, a regression line that is a linear relationship represented by equation (5) is memorized. The regression line represented by this 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. However, the pulse wave velocity PWV in equation (5) is obtained from the time difference Δt between the positions of the notch MWLNP of a pair of pulse waves respectively obtained from the upstream expansion bag 22 and the downstream expansion bag 26 during a constant pressure period in a pressure range lower than the minimum blood pressure value DAP of the living body 14. The position of this notch MWLNP is obtained from the first derivative waveform of the pulse wave MW or the second derivative waveform of the pulse wave MW as shown in FIGS. 16 and 17 described above.

[0126] PWV 2 =s·(DNAP - Pc)+i ··· (5) However, s indicates the slope of the regression line, and i indicates the intercept of the regression line.

[0127] FIG. 21 shows two-dimensional coordinate data indicating the results of Experiment No. 9 conducted by the inventors regarding the relationship between the transmural pressure (DNAP - Pc) and the square value PWV 2 of the pulse wave velocity for a predetermined living body 14, along with the regression line y and the coefficient of determination R 2 shown. The coefficient of determination R 2 in this result is 0.9779, which is a value close to 1, so it is a regression line showing a high-quality linear relationship.

[0128] Similar to the blood pressure measurement unit 84, the blood pressure measurement unit 184 measures the actual minimum blood pressure value DAP R of the living body 14, which is the subject to be measured, using a blood pressure measuring device prior to the generation of the specific relationship of equation (6) described later by the specific relationship generation unit 192. Also, the blood pressure measurement unit 184 measures the mean blood pressure value MAP of the living body 14 using a blood pressure measuring device, and uses the measured mean blood pressure value MAP as the actual notch blood pressure value DNAP RIt is determined as follows. The above mean blood pressure value MAP is the compression pressure Pc when showing the maximum amplitude of the pulse wave. For example, in an oscillometric automatic blood pressure measuring device, the compression pressure Pc of the compression band 12 is the compression pressure Pc of the envelope (envelope) connecting the peak values of the pulse wave signal SM2 (intermediate pulse wave) sequentially obtained in the process of being decreased from a preset pressure increase target pressure value PCM that is sufficiently higher than the systolic blood pressure value SAP. The compression pressure Pc at the time when showing the maximum value (maximum peak value) is measured as the mean blood pressure value MAP. The mean blood pressure value MAP measured in this way approximates and is equivalent to the notch blood pressure value DNAP of the living body 14. FIG. 22 shows the experimental results conducted by the present inventors, showing the correlation between the notch blood pressure value DNAP directly measured using a catheter and the actually measured mean blood pressure value MAP in an animal (dog).

[0129] Similar to the compression pressure control unit 86, the compression pressure control unit 186 executes compression pressure control for blood pressure measurement as shown in the section from the time point t1 to the time point t11 in FIG. 6, and then performs compression pressure control in the section shown in the section between the time points tk1 and tk5 for generating the intrinsic relationship of the formula (6). Then, in order to estimate the systolic blood pressure value SAPe from the estimated notch blood pressure value DNAPe and the estimated diastolic blood pressure value DAPe of the living body 14, in response to a blood pressure estimation start command (time point tm1) repeatedly issued at a predetermined blood pressure estimation cycle, the compression pressure Pc is controlled so that a constant monitoring pressure PcHm shown in the monitoring pressure maintenance section from the time point tm1 to the time point tm3 in FIG. 6 is formed.

[0130] Similar to the pulse wave extraction unit 88, the pulse wave extraction unit 188 extracts and stores a pair of pulse waves MW11 and MW13 from the pulse wave signals SM1 and SM3 obtained by passing through a low-pass filter for pulse wave discrimination that discriminates signals in a wavelength band of 0 Hz to less than 25 Hz from the output signal indicating the compression pressure PcH1 in the upstream expansion bag 22 from the first pressure sensor T1 and the output signal indicating the compression pressure PcH1 of the downstream expansion bag 26 from the third pressure sensor T3 within a pressure sufficiently lower than the minimum blood pressure value DAP of the living body 14, which is the subject being measured, for example, within the range of 20 to 60 mmHg. Alternatively, the pulse wave extraction unit 188 extracts and stores a pair of pulse waves MW21 and MW23 from a pair of the upstream expansion bag 22 and the downstream expansion bag 26 through a low-pass filter for pulse wave discrimination that discriminates signals in a wavelength band of less than 25 Hz from the output signal indicating the compression pressure PcH2 in the upstream expansion bag 22 from the first pressure sensor T1 and the output signal indicating the compression pressure PcH2 in the downstream expansion bag 26 from the third pressure sensor T3 under the second maintenance pressure PcH2 in the second maintenance section set to a value lower than the first maintenance pressure PcH1.

[0131] Similar to the pulse wave propagation velocity calculation unit 90, the pulse wave propagation velocity calculation unit 190 calculates the time difference Δt113 between the minimum points of the pair of pulse waves MW11 and MW13 extracted in the first maintenance section (from the time point tk2 to the time point tk3) in order to generate the specific relationship of equation (2) between the minimum blood pressure value DAP and the pulse wave propagation velocity in a predetermined living body 14. D And calculates the pulse wave propagation velocity PWV1 D (=L13 / Δt113 D ) and calculates the time difference Δt213 between the minimum points of the pair of pulse waves MW21 and MW23 extracted in the second maintenance section (from the time point tk4 to the time point tk5). D And calculates the pulse wave propagation velocity PWV2 D (=L13 / Δt213 D ) and stores them.

[0132] In order to generate the specific relationship of formula (6) between the notch blood pressure value DNAP and the pulse wave velocity PWV in a predetermined living body 14, the pulse wave velocity calculation unit 190 calculates the time difference Δt113 between the notch portions of a pair of pulse waves MW11 and MW13 extracted in the first maintenance interval (from the time point tk2 to the time point tk3). DN and calculates the pulse wave velocity PWV1 in the first maintenance interval DN (=L13 / Δt113 DN ). Then, the time difference Δt213 between the notch portions of a pair of pulse waves MW21 and MW23 extracted in the second maintenance interval (from the time point tk4 to the time point tk5) is calculated, and the pulse wave velocity PWV2 DN in the second maintenance interval is calculated DN (=L13 / Δt213 DN ) and stored.

[0133] After the specific relationships of formula (2) and formula (6) are generated, the pulse wave velocity calculation unit 190 calculates, based on the time difference Δt113 between the minimum portions of a pair of pulse waves MW11 and MW13 and the time difference Δt113 between the notch portions in the monitor pressure maintenance interval (from the time point tm2 to the time point tm3) of a constant monitor pressure PcHm formed for each blood pressure estimation start command (at the time point tm1), the pulse wave velocity PWV used for the estimation of the estimated minimum blood pressure value DAPe using formula (2) and the pulse wave velocity PWV used for the estimation of the estimated notch blood pressure value DNAPe using formula (6), and stores them respectively. D and the time difference Δt113 between the notch portions DN and calculates the pulse wave velocity PWV used for the estimation of the estimated minimum blood pressure value DAPe using formula (2) D and the pulse wave velocity PWV used for the estimation of the estimated notch blood pressure value DNAPe using formula (6) DN and stores them respectively.

[0134] Similar to the specific relationship generation unit 92 in the aforementioned Example 1, the specific relationship generation unit 192 generates and stores, for the living body 14 which is the subject to be measured, the specific relationship shown in formula (2) between the actual minimum blood pressure value DAP R and the actual compression pressures in the low pressure interval, that is, the compression pressures PcH1 and PcH2, and the actual pulse wave velocities PWV1 D , PWV2 D obtained under the compression pressures PcH1 and PcH2. Then, the specific relationship generation unit 192 generates the actual notch blood pressure value DNAP Rand the actual compression pressures in the low-pressure section, namely compression pressures PcH1 and PcH2, and the actual pulse wave velocity PWV1 obtained under the compression pressures PcH1 and PcH2 DN , PWV2 DN Generate and store the intrinsic relationships shown in Equation (6) between them respectively.

[0135] DNAPe = PWV DN 2 / s DN -i DN / s DN +Pc ··· (6)

[0136] The intrinsic relationship generation unit 192 substitutes the notch blood pressure value DNAP actually measured by the blood pressure measurement unit 184 into the two equations respectively shown by Equation (5) indicating a linear relationship. For each of the plurality of compression pressures (the first maintenance pressure in the first maintenance section) PcH1 and the compression pressure (the second maintenance pressure in the second maintenance section) PcH2 within the low-pressure section lower than the lowest blood pressure value DAP of the living body 14 being measured, the propagation time Δt113 between the notch sites of a pair of pulse waves obtained respectively R is used as DNAP, and the actual pulse wave velocity based on the time difference Δt213 DN and the time difference Δt213 DN is PWV1 DN and PWV2 DN When substituting respectively, the i DN and s DN obtained respectively as the solutions of the two unknowns i and s of the two equations are used as the actually measured calibration values, and the intrinsic relationship for notch blood pressure estimation represented by Equation (6) is generated for the living body 14 being measured.

[0137] The blood pressure estimation unit 194 includes a lowest blood pressure estimation unit 196, a notch blood pressure estimation unit 200, and a highest blood pressure estimation unit 198. After the intrinsic relationship shown in Equation (2) is obtained, the lowest blood pressure estimation unit 196, for each blood pressure estimation cycle, the actual compression pressure PcH1 in the low-pressure section sufficiently lower than the lowest blood pressure value DAP of the living body 14 and the actual pulse wave velocity PWV1 obtained under the compression pressure PcH1 D , or the actual compression pressure PcH2 and the actual pulse wave velocity PWV2 obtained under the compression pressure PcH2D By applying it to the specific relationship shown in formula (2), the estimated minimum blood pressure value DAPe of the living body 14, which is the subject to be measured, is estimated.

[0138] After the specific relationship shown in formula (6) is obtained, the notch blood pressure estimation unit 200, for each blood pressure estimation cycle, the actual compression pressure PcH1 in a low pressure section that is sufficiently lower than the minimum blood pressure value DAP of the living body 14 and the actual pulse wave velocity PWV1 obtained under the compression pressure PcH1 DN or the actual compression pressure PcH2 and the actual pulse wave velocity PWV2 obtained under the compression pressure PcH2 DN By applying it to the specific relationship shown in formula (6), the estimated notch blood pressure value DNAPe of the living body 14, which is the subject to be measured, is estimated.

[0139] Since the magnitude of the pulse wave MW obtained at a compression pressure lower than the minimum blood pressure value DAP of the living body 14, for example, the monitor pressure PcHm, by the maximum blood pressure estimation unit 198 has the same unit (mmHg) as the compression pressure Pc, as shown in FIG. 23, the minimum part of the pulse wave MW corresponds to the minimum blood pressure value DAP, the maximum part corresponds to the maximum blood pressure value SAP, and the notch part corresponds to the notch blood pressure value DNAP. Using this, based on the estimated minimum blood pressure value DAPe estimated by the minimum blood pressure estimation unit 196, the estimated notch blood pressure value DNAPe estimated by the notch blood pressure estimation unit 200, the compression pressure Pc at the minimum part of the actual pulse wave MW of the living body 14 to be measured, and the compression pressure Pc at the notch part, the relationship shown in FIG. 24 is generated.

[0140] Then, the maximum blood pressure estimation unit 198 estimates the estimated maximum blood pressure value SAPe based on the compression pressure (cuff pressure) Pc indicating the magnitude of the maximum part of the actual pulse wave MW obtained at the monitor pressure PcHm from the living body 14 to be measured, according to the relationship shown in FIG. 24. FIG. 24 shows that when the magnitude of the maximum part of the actual pulse wave MW was 55.2 mmHg, the estimated maximum blood pressure value SAPe was 115 mmHg. Incidentally, in FIG. 24, the estimated maximum blood pressure value SAPe is estimated assuming a linear relationship between the estimated minimum blood pressure value DAPe, the estimated notch blood pressure value DNAPe, and the corresponding compression pressure Pc, but a non-linear relationship such as an exponential function may be assumed and used.

[0141] FIG. 25 is a flowchart for explaining the main part of the control operation of the electronic control device 170 of the present embodiment. In the following, the explanation will be centered on the differences from FIG. 19.

[0142] S31 to S36 are the same as S1 to S6 in FIG. 19. At S37 corresponding to the blood pressure measurement unit 184, the notch blood pressure value DNAP R is measured. For example, in an oscillometric automatic blood pressure measuring device, the compression pressure Pc of the compression band 12 is the maximum value (maximum peak value) of the envelope connecting the peak values of the pulse wave signals SM2 (intermediate pulse waves) sequentially obtained in the process of decreasing from a preset pressure increase target pressure value PCM that is sufficiently higher than the systolic blood pressure value SAP. The compression pressure Pc at the time indicating is measured as the mean blood pressure value MAP.

[0143] Subsequently, at S38 corresponding to the compression pressure control unit 186, the first holding pressure PcH1 is maintained in the same manner as S8 in FIG. 19, and at S39 corresponding to the pulse wave extraction unit 188, a pulse wave is extracted at the first holding pressure PcH1 in the same manner as S9 in FIG. 19.

[0144] At S40 corresponding to the pulse wave propagation velocity calculation unit 190, the pulse wave propagation velocity PWV1 D and the pulse wave propagation velocity PWV1 DN are calculated. The pulse wave propagation velocity PWV1 D is for generating the specific relationship of formula (2) between the diastolic blood pressure value DAP and the pulse wave propagation velocity PWV in a predetermined living body 14, and is the time difference Δt113 D between the minimum parts of a pair of pulse waves MW11 and MW13 extracted in the first holding period (from the time point tk2 to the time point tk3). The pulse wave propagation velocity PWV1 D (=L13 / Δt113 D ) in the first holding period. The pulse wave propagation velocity PWV1 DN is used to generate the specific relational expression (6) of the living body 14 to be measured, and is the time difference Δt113 DNThe pulse wave velocity PWV1 in the first maintenance interval calculated from DN (=L13 / Δt113 DN ) is as follows.

[0145] In S41 corresponding to the compression control unit 186, similar to S11 in FIG. 19, the second maintenance pressure PcH2 is maintained. In S42 corresponding to the pulse wave extraction unit 188, similar to S12 in FIG. 19, a pulse wave is extracted at the second maintenance pressure PcH2.

[0146] In S43 corresponding to the pulse wave velocity calculation unit 190, the pulse wave velocity PWV2 at the second maintenance pressure PcH2 D and the pulse wave velocity PWV2 DN are calculated. The pulse wave velocity PWV2 D is for generating the specific relationship of formula (2) between the minimum blood pressure value DAP and the pulse wave velocity PWV in a predetermined living body 14, and is the time difference Δt213 between the minimum parts of a pair of pulse waves MW21 and MW23 extracted in the second maintenance interval (from the time point tk4 to the time point tk5) D The pulse wave velocity PWV2 in the second maintenance interval calculated from D (=L13 / Δt213 D ) is as follows. The pulse wave velocity PWV2 DN is used to generate the specific relational expression (6) of the living body 14 to be measured, and is the time difference Δt213 between the notch parts of a pair of pulse waves MW21 and MW23 extracted at the second maintenance pressure PcH2 DN The pulse wave velocity PWV2 in the second maintenance interval calculated from DN (=L13 / Δt213 DN ) is as follows.

[0147] In S44 corresponding to the specific relationship generation unit 192, the minimum blood pressure value DAP actually measured in S36 R is substituted into two equations respectively represented by formula (1) showing a linear relationship, and the propagation time Δt113 between the minimum parts of a pair of pulse waves obtained for each of the first maintenance pressure PcH1 in the first maintenance interval and the second maintenance pressure PcH2 in the second maintenance interval D and the time difference Δt213 DThe actual pulse wave velocity PWV1 based on D and PWV2 D When each is substituted, the i obtained as the solution of the two unknowns i and s of the two equations D and s D By using i and s as the actually measured calibration values, the specific relationship for estimating the minimum blood pressure represented by equation (2) is generated for the living body 14 which is the subject to be measured.

[0148] Also, in S44, the notch blood pressure value DNAP measured in S37 is substituted into the two equations respectively shown by equation (5) indicating a linear relationship R The propagation time Δt113 between the notch parts of a pair of pulse waves respectively obtained for each of the first holding pressure PcH1 in the first holding section and the second holding pressure PcH2 in the second holding section DN and the time difference Δt213 DN The actual pulse wave velocity PWV1 based on DN and PWV2 DN When each is substituted, the i obtained as the solution of the two unknowns i and s of the two equations DN and s DN By using i and s as the actually measured calibration values, the specific relationship for estimating the notch blood pressure represented by equation (6) is generated for the living body 14 which is the subject to be measured.

[0149] In the subsequent S45, in the same manner as in S15, the rapid exhaust valve 52 is operated so that the pressures in the upstream expansion bag 22, the intermediate expansion bag 24, and the downstream expansion bag 26 are each exhausted to the atmospheric pressure.

[0150] In S46 to S48, similar to S16 to S18 in FIG. 19, when a blood pressure estimation start command is issued, the compression pressure Pc is increased to a compression pressure between 20 and 60 mmHg, which is lower than the minimum blood pressure value DAP of the living body 14, for example, the monitor pressure PcHm, and is controlled to form a monitor pressure maintenance section (from the time point tm2 to the time point tm3) that maintains the monitor pressure PcHm. An output signal indicating the compression pressure PcHm in the upstream expansion bag 22 from the first pressure sensor T1 and an output signal indicating the compression pressure PcHm of the downstream expansion bag 26 from the third pressure sensor T3 below the monitor pressure PcHm in the monitor pressure maintenance section are passed through a band-pass filter for pulse wave discrimination, and a pair of pulse waves MWm1 and pulse wave MWm3 are respectively extracted.

[0151] Next, in S49 corresponding to the pulse wave propagation velocity calculation unit 190, the time difference Δtm13 between the minimum parts of a pair of pulse waves MWm1 and pulse wave MWm3 D is calculated, and from the time difference Δtm13 D , the pulse wave propagation velocity PWVm in the monitor pressure maintenance section D (=L13 / Δtm13 D ) is calculated. Also, the time difference Δtm13 between the notch parts of a pair of pulse waves MWm1 and pulse wave MWm3 DN is calculated, and from the time difference Δtm13 DN , the pulse wave propagation velocity PWVm in the monitor pressure maintenance section DN (=L13 / Δtm13 DN ) is calculated.

[0152] Next, in S50 corresponding to the minimum blood pressure estimation unit 196, the estimated minimum blood pressure value DAPe is calculated by applying the monitor pressure PcHm and the pulse wave propagation velocity PWVm to the formula (2) showing the specific relationship of the living body 14 to be measured. Also, in S51 corresponding to the notch blood pressure estimation unit 200, the estimated notch blood pressure value DNAPe is calculated by applying the monitor pressure PcHm and the pulse wave propagation velocity PWVm to the formula (6) showing the specific relationship of the living body 14 to be measured. D DN

[0153] Then, in S52 corresponding to the maximum blood pressure estimation unit 198, based on the estimated minimum blood pressure value DAPe estimated by S50, the estimated notch blood pressure value DNAPe estimated by S51, and the compression pressure Pc at the minimum and notch parts of the actual pulse wave MW of the living body 14 to be measured, the relationship shown in FIG. 24 is generated. Next, in S52, from the relationship shown in FIG. 24, based on the compression pressure Pc indicating the magnitude of the maximum part of the actual pulse wave MW obtained at the monitor pressure PcHm from the living body 14 to be measured, the estimated maximum blood pressure value SAPe is estimated. Note that in FIG. 24, a linear relationship is assumed and estimated, but a non-linear relationship such as an exponential function may be assumed and estimated.

[0154] In S53 to S55, similar to S22 to S24 in FIG. 19, the estimated minimum blood pressure value DAPe and the estimated maximum blood pressure value SAPe are stored and displayed on the display device 78. While the stop (off) operation by the blood pressure estimation start operation button 80 is negated, the blood pressure estimation routine below S46 is repeated. However, when the stop (off) operation by the blood pressure estimation start operation button 80 is affirmed, the blood pressure monitoring routine is terminated.

[0155] As described above, according to the electronic control device 170 of the present embodiment, in the specific relationship generation unit 192, the actual notch blood pressure value DNAP of the living body 14 to be measured R and the first holding pressure PcH1 and the second holding pressure PcH2 which are actual compression pressures, and the time difference Δt113 between the notch parts of the pulse waves respectively obtained under the first holding pressure PcH1 and the second holding pressure PcH2 which are the actual compression pressures DN and the time difference Δt213 DN Based on the pulse wave velocity PWV1 DN and PWV2 DN Using these, the specific relational expression (6) of the living body 14 between the estimated notch blood pressure value DNAPe, the compression pressure, and the pulse wave velocity is generated. Therefore, the blood pressure estimation unit 194 is based on the actual monitor pressure PcHm obtained in the low pressure section lower than the minimum blood pressure value DAP of the living body 14 and the time difference between the notch parts between the pulse waves obtained under the actual monitor pressure PcHm. The pulse wave velocity PWV DNBy applying the above to the inherent relation (6) of the living body generated by the inherent relation generating unit 192, the estimated dicrotic blood pressure value DNAPe of the living body 14 can be easily estimated.

[0156] In addition, according to the electronic control device 170 of the present embodiment, the propagation time (time difference Δt113 ) between the dicrotic sites of a pair of pulse waves obtained for each of the plurality of first maintenance pressures PcH1 and second maintenance pressures PcH2 is calculated. DN and time difference Δt213 DN ) is the propagation time between the zero crossing points going from negative to positive in the first derivative waveform of the pulse wave. In this way, the propagation time between the dicrotic sites of a pair of pulse waves can be easily obtained, and the estimation accuracy of the estimated dicrotic blood pressure value DNAPe can be improved.

[0157] According to the electronic control device 170 of the present embodiment, the blood pressure estimation unit 194 estimates the actual monitor pressure PcHm and the actual pulse wave velocity PWVm obtained under the monitor pressure PcHm in a low pressure range lower than the minimum blood pressure DAP of the subject living body 14. DN Since the device includes a diastolic blood pressure estimator 200 that estimates the estimated diastolic blood pressure value DNAPe of the living body 14 by successively applying the above equation to the inherent relationship of equation (6), the estimated diastolic blood pressure value DNAPe of the living body 14 can be easily estimated.

[0158] According to the electronic control device 170 of the present embodiment, the blood pressure estimation unit 194 estimates the actual monitor pressure PcHm and the actual pulse wave velocity PWVm obtained under the monitor pressure PcHm in a low pressure range lower than the minimum blood pressure DAP of the subject living body 14. DBy sequentially applying it to the eigenvalue relationship of formula (2), a minimum blood pressure estimation unit 196 that estimates the estimated minimum blood pressure value DAPe of the living body 14, and the estimated minimum blood pressure value DAPe estimated by the minimum blood pressure estimation unit 196 and the estimated notch blood pressure value DNAPe estimated by the notch blood pressure estimation unit 200. Based on this, a relationship (Fig. 24) between the magnitude of the pulse wave and the estimated blood pressure value APe in the monitor pressure PcHm section lower than the minimum blood pressure value DAP is generated, and the maximum value of the actual pulse wave sequentially obtained under the monitor pressure PcHm is applied to this relationship. And a maximum blood pressure estimation unit 198 that estimates the estimated maximum blood pressure value SAPe. As a result, even when the time difference between the maximum parts of a pair of pulse waves sequentially obtained under the monitor pressure PcHm cannot be accurately obtained, the estimated maximum blood pressure value SAPe of the subject can be easily estimated.

[0159] As described above, one embodiment of the present invention has been described in detail with reference to the drawings. However, the present invention is not limited to this embodiment and can be implemented in other modes.

[0160] For example, in the above-described blood pressure monitoring device 10, both the estimated maximum blood pressure value SAPe and the estimated minimum blood pressure value DAPe were estimated, but it may 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 formulas (1) and (3) stored in the linear relationship storage unit 82 becomes unnecessary, and one of the minimum blood pressure estimation unit 96 and the maximum blood pressure estimation unit 98 becomes unnecessary.

[0161] Further, in the above-described embodiment, a plurality of pulse waves are extracted for each of the first maintenance section that maintains the first maintenance pressure PcH1, the second maintenance section that maintains the second maintenance pressure PcH2, and the monitor pressure maintenance section that maintains the monitor pressure PcHm, and the plurality of pulse waves are extracted. The average value of the time differences taken from these may be used.

[0162] Further, in the first and second embodiments, the compression band 12 includes three inflatable bags, that is, an upstream inflatable bag 22, an intermediate inflatable bag 24, and a downstream inflatable bag 26. However, at least two inflatable bags may be provided.

[0163] In addition, in the first and second embodiments, a stepwise pressure reduction is adopted for the compression band 12, but a continuous gradual pressure reduction may also be used.

[0164] Note that the above is merely one embodiment, and although not all examples are illustrated one by one, the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art without departing from the gist thereof.

Explanation of Reference Numerals

[0165] 10, 110: Blood pressure monitoring device 12: Compression band 14: Living body (subject to be measured) 16: Upper arm (compressed part) 18: Artery 22: Upstream expansion bag (expansion bag) 24: Intermediate expansion bag (expansion bag) 26: Downstream expansion bag (expansion bag) 82, 182: Linear relationship memory unit 84, 184: Blood pressure measurement unit 86, 186: Compression pressure control unit 88, 188: Pulse wave extraction unit 90, 190: Pulse wave velocity calculation unit 92, 192: Intrinsic relationship generation unit 94, 194: Blood pressure estimation unit 96, 196: Minimum blood pressure estimation unit (blood pressure estimation unit) 98, 198: Maximum blood pressure estimation unit (blood pressure estimation unit) 200: Notch blood pressure estimation unit

Claims

Claim 1 A blood pressure monitoring device having a plurality of inflatable bags that form independent air chambers arranged in the width direction, comprising a compression band that is wound around a compressed site of a subject to compress the artery of the subject, and repeatedly estimates the estimated blood pressure value of the subject, A linear relationship storage unit that stores a pre-stored linear relationship between the square value of the pulse wave propagation velocity detected respectively under a plurality of compression pressures of the compression band in a low pressure section lower than the minimum blood pressure value of the living body, and a plurality of transmural pressures of the artery, which are the pressure differences between the blood pressure value in the artery and the compression pressure of the compression band, A blood pressure measurement unit that measures the actual blood pressure value of the subject based on the pulse synchronous wave from the artery obtained during the blood pressure drop process after compressing the compressed site of the subject with a compression pressure higher than the maximum blood pressure value of the subject, A specific relationship generation unit that generates a specific relationship for the subject between the actual blood pressure value, the actual compression pressure, and the actual pulse wave propagation velocity of the subject by applying the actual blood pressure value, the actual compression pressure in the low pressure section, and the actual pulse wave propagation velocity obtained respectively under the actual compression pressure of the subject to the linear relationship, A blood pressure estimation unit that estimates the estimated blood pressure value by applying the actual compression pressure in the low pressure section and the actual pulse wave propagation velocity obtained under the actual compression pressure of the subject to the specific relationship for the subject, and includes A blood pressure monitoring device characterized by the above. Claim 2 The estimated blood pressure value estimated by the blood pressure estimation unit is the estimated minimum blood pressure value DAPe of the subject, The linear relationship is a regression line represented by the following formula (1), where the pulse wave propagation velocity of the living body is PWV, the minimum blood pressure value of the living body is DAP, and the compression pressure of the living body is Pc The blood pressure monitoring device according to claim 1, characterized by the above. PWV ２ = s·(DAP - Pc) + i... (1) However, s represents the slope of the regression line, and i represents the intercept of the regression line. Claim 3 The unique relationship of the subject to be measured is obtained by substituting the minimum blood pressure value actually measured for the subject as DAP into each of the two equations represented by the following formula (1), substituting different actual compression pressures Pc within the low pressure range as Pc, and using the actual pulse wave velocity PWV based on the propagation time between the minimum parts of the pulse waves obtained for each of the different actual compression pressures Ｄ When substituting each as PWV, the i Ｄ and s Ｄ obtained as the solutions of the unknowns i and s respectively are taken as the actual measurement calibration values, and are represented by the following formula (2) The blood pressure monitoring device according to claim 2, characterized by the above. DAPe = PWV Ｄ ２ / s Ｄ -i Ｄ / s Ｄ + Pc ··· (2) Claim 4 The propagation time between the minimum parts of the pulse waves obtained respectively for each actual compression pressure is the propagation time between the vertices that occur corresponding to the rising points of the pulse waves obtained respectively for each actual compression pressure in the second derivative waveform of the pulse waves obtained respectively for each actual compression pressure, The blood pressure monitoring device according to claim 3, characterized by the above. Claim 5 The blood pressure estimation unit includes a minimum blood pressure estimation unit that estimates the estimated minimum blood pressure value by sequentially applying the actual compression pressure in the low pressure section and the actual pulse wave propagation velocity obtained under the actual compression pressure to the intrinsic relationship of formula (2) for the subject to be measured. The blood pressure monitoring device according to claim 3 or 4, characterized in that.

6. The estimated blood pressure value estimated by the blood pressure estimation unit is the estimated maximum blood pressure value SAPe of the subject to be measured, The linear relationship is a regression line represented by the following formula (3), where the pulse wave propagation velocity of the living body is PWV, the maximum blood pressure value of the living body is SAP, and the compression pressure of the living body is Pc. The blood pressure monitoring device according to claim 1, characterized in that. PWV ２ = s · (SAP - Pc) + i... (3) However, s represents the slope of the regression line, and i represents the intercept of the regression line.

7. The unique relationship of the subject to be measured is obtained by substituting the measured maximum blood pressure value of the subject to be measured as SAP into two equations respectively represented by the following formula (3), substituting different actual compression pressures Pc within the low-pressure range as Pc respectively, and substituting the actual pulse wave velocity PWV based on the propagation time between the maximum positions of the pulse waves obtained for each of the different actual compression pressures as PWV respectively Ｓ When the obtained i Ｓ and s Ｓ are taken as the measured calibration values, they are represented by the following formula (4) The blood pressure monitoring device according to claim 6, characterized in that. SAPe = PWV Ｓ ２ / s Ｓ -i Ｓ / s Ｓ + Pc ··· (4)

8. The propagation time between the maximum parts of the pulse waves obtained for each of the actual compression pressures is the propagation time between the maximum points of the pulse waves obtained for each of the actual compression pressures. The blood pressure monitoring device according to claim 7, characterized in that.

9. The blood pressure estimation unit includes a maximum blood pressure estimation unit that estimates the estimated maximum blood pressure value by sequentially applying the actual compression pressure in the low pressure section and the actual pulse wave propagation velocity obtained under the actual compression pressure to the intrinsic relationship of formula (4) for the subject to be measured. The blood pressure monitoring device according to claim 7 or 8, characterized in that.

10. The estimated blood pressure value estimated by the blood pressure estimation unit is the estimated notch blood pressure value DNAPe of the subject to be measured, which is the compression pressure at the time of occurrence of a notch site locally formed after the maximum part of the pulse wave. The linear relationship is a regression line represented by the following formula (5), where the pulse wave propagation velocity of the living body is PWV, the notch blood pressure value of the living body is DNAP, and the compression pressure of the living body is Pc. The blood pressure monitoring device according to claim 1, characterized in that. PWV ２ = s·(DNAP - Pc) + i ··· (5) However, s represents the slope of the regression line, and i represents the intercept of the regression line.

11. The unique relationship of the subject to be measured is obtained by substituting the notch blood pressure values actually measured for the subject as DNAP into two equations respectively represented by the following formula (5), substituting different actual compression pressures Pc within the low-pressure range as Pc respectively, and using the actual pulse wave velocity PWV based on the propagation time between the notch sites of the pulse wave obtained for each of the different actual compression pressures ＤＮ When substituting PWV as PWV respectively, the obtained i as the solution of the unknowns i and s ＤＮ and s ＤＮ Taking i and s as the actually measured calibration values, it is represented by the following formula (6) The blood pressure monitoring device according to claim 10, characterized in that. DNA Pe = PWV ＤＮ ２ / s ＤＮ -i ＤＮ / s ＤＮ + Pc ··· (6)

12. The propagation time between the notch sites of the pulse waves obtained for each of the actual compression pressures is the propagation time between the peaks that occur after the time corresponding to the maximum part of the pulse waves obtained for each of the actual compression pressures in the second derivative waveform of the pulse waves obtained for each of the actual compression pressures. The blood pressure monitoring device according to claim 11, characterized in that.

13. The blood pressure estimation unit includes a notch blood pressure estimation unit that estimates the estimated notch blood pressure value by sequentially applying, to the subject, the actual compression pressure and the actual pulse wave velocity obtained under the actual compression pressure in the low pressure section to the intrinsic relationship of equation (6). The blood pressure monitoring device according to claim 11 or 12, characterized by the above.

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