JP2012071058A - Automatic blood pressure measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic blood pressure measuring apparatus capable of obtaining accurate pulse waves by appropriately applying a compression pressure to an artery inside a part to be compressed and obtaining a highly accurate highest blood pressure value on the basis of the pulse waves.SOLUTION: A pressure band 12 includes expansion bags 22, 24 and 26 which are connected in the width direction and provided with independent air chambers for respectively compressing an upper arm 10. By successively calculating an amplitude ratio r23 which is a value in which the amplitude value A2 of pulse wave signals SM2 from the intermediate expansion bag 24 positioned more on the upstream side than the downstream side expansion bag 26 is divided by the amplitude value A3 of pulse wave signals SM3 from the downstream side expansion bag 26 positioned on the downstream side of the artery 16 inside the upper arm 10 among the expansion bags, and determining the highest blood pressure value SBP of a living body on the basis of the amplitude ratio r23, the accurate pulse wave signals SM are obtained by applying the compression pressure to the artery 16 in an equal pressure distribution from the respective expansion bags turned to the state of being independent of each other regarding a pressure fluctuation, and thus the highly accurate highest blood pressure value SBP is obtained.

Description

  The present invention relates to an automatic blood pressure measurement device having a compression band wound around a compression site in order to detect a pulse wave generated from an artery in the compression site that is a limb of a living body such as an arm or an ankle. is there.

  A compression band wound around the compressed part of the living body, and in the process of changing the compression pressure value of the compression band, pulse waves that are pressure oscillations in the compression band are sequentially extracted, and based on the change of the pulse wave There is known an automatic blood pressure measurement device that determines a blood pressure value of a living body. The inflatable bag provided in the compression band requires a sufficiently large compression width dimension with respect to the diameter of the compressed part and has a relatively large capacity, so that it responds to changes in the volume of the artery in the compressed part. The pulse wave, which is the pressure vibration generated in this way, tends to be a weak signal, which has been a factor in reducing the measurement accuracy.

  On the other hand, as shown in Patent Document 1, in order to clearly detect a change in the volume of the artery, a detection expansion bag with a small volume compared to the main expansion bag is formed in the main expansion bag as a whole in the width direction. A two-layered compression band has been proposed in which it is provided so as to overlap with a part of the inside of the bag and a shielding plate is provided between the detection expansion bag and the main expansion bag. According to this, pressurization by the other part of the main inflation bag is indirectly performed through the detection inflation bag while pressurization by a part of the main inflation bag is directly performed on the pressed portion.

Japanese Patent Laid-Open No. 05-269089

  However, according to the conventional automatic blood pressure measuring device having the two-layered compression band shown in Patent Document 1, the pressure of the main inflation bag is appropriate because the detection inflation bag is located on the skin side of the living body. Since it is not added to the artery, it is difficult to obtain an accurate pulse wave, and the accuracy of the maximum blood pressure value determined based on the pulse wave is not good.

  An object of the present invention is to provide an automatic blood pressure measurement device capable of determining a highly accurate systolic blood pressure value based on a pulse wave obtained when an artery in a compressed part of a living body is compressed. is there.

  The present inventor made a trial production of a triple cuff having three air chambers capable of independently compressing a living body against the background described above, and compared cuff pulse waves obtained independently from these three air chambers. While the cuff pressure was high, the difference in amplitude was greatly different, but when the cuff pressure was close to the maximum blood pressure value of the living body, the amplitude between cuff pulse waves was found to be similar. The present invention has been made based on such findings.

  That is, the gist of the invention according to claim 1 is that: (a) a pressure band wound around a compressed portion of a living body is provided, and pressure vibration in the compression band is changed in the process of changing the pressure value of the compression band. Is an automatic blood pressure measuring device that sequentially extracts a pulse wave and determines a blood pressure value of the living body based on a change in the pulse wave, and (b) the compression band is linked in the width direction to A plurality of inflatable bags each having an independent air chamber that compresses each of the compressed sites; and (c) a downstream inflation located downstream of the artery in the compressed site of the plurality of inflatable bags An amplitude ratio between the amplitude value of the pulse wave from the bag and the amplitude value of the pulse wave from a predetermined expansion bag located upstream of the downstream expansion bag is sequentially calculated, and the living body is calculated based on the amplitude ratio. There is to determine the systolic blood pressure value.

  The gist of the invention according to claim 2 is that, in the invention according to claim 1, (a) the amplitude ratio is obtained by calculating an amplitude value of a pulse wave from the predetermined expansion bag from the downstream expansion bag. (B) a first amplitude ratio determination value in which the sequentially calculated amplitude ratio is set in advance in the process of decreasing the compression pressure value of the compressed compression band. The compression pressure value of the compression band when the pressure becomes smaller is determined as the maximum blood pressure value of the living body.

  Further, the gist of the invention according to claim 3 is that, in the invention according to claim 1 or 2, the compression band is formed of a flexible sheet positioned at a predetermined interval in the longitudinal direction of the pressed portion. A pair of upstream inflatable bags and downstream inflatable bags arranged between the upstream inflatable bag and the downstream inflatable bag so as to be continuous in the longitudinal direction of the pressed portion, and the upstream inflatable bag and the downstream side The expansion bag has an intermediate expansion bag having an independent air chamber.

  According to a fourth aspect of the present invention, there is provided the gist of the invention according to the third aspect, wherein the pressure value of the pressure band that has been boosted is set to the upstream expansion bag, the intermediate expansion bag, and the downstream side. A value obtained by dividing the amplitude value of the pulse wave from the upstream inflatable bag by the amplitude value of the pulse wave from the intermediate inflating bag in the process of lowering the pressure to be pressed with the same pressure by the expansion bag is preliminarily obtained. A value obtained by dividing the amplitude value of the pulse wave from the intermediate expansion bag by the amplitude value of the pulse wave from the downstream expansion bag is smaller than the set second amplitude ratio determination value. The compression pressure value of the intermediate expansion bag when the value becomes smaller than the value is determined as the maximum blood pressure value of the living body.

  A gist of the invention according to claim 5 is the invention according to any one of claims 1 to 4, further comprising: (a) a pressure sensor that detects pressures in the plurality of inflatable bags; b) After increasing the compression pressure value of the plurality of inflatable bags of the compression band wound around the compression site to a value sufficient to stop the artery in the compression site, the compression pressure of the compression zone In the process of decreasing the value, the compression pressure value of the compression band is held for a predetermined time every predetermined amount of deceleration pressure reduction, and the pulse wave that is the pressure vibration in the compression band is detected within the predetermined time.

  According to the automatic blood pressure measurement device of the invention according to claim 1, the compression band has a plurality of inflatable bags having independent air chambers that are linked in the width direction and respectively compress the compressed portion of the living body, Among the plurality of inflation bags, the amplitude value of the pulse wave from the downstream inflation bag located on the downstream side of the artery in the compressed site, and a predetermined inflation bag located on the upstream side of the downstream inflation bag The amplitude ratio with the amplitude value of the pulse wave from is sequentially calculated, and the systolic blood pressure value of the living body is determined based on the amplitude ratio. Accurate pulse waves can be obtained from each inflatable bag by applying compression pressure to the artery in the compressed region with an even pressure distribution. Therefore, a highly accurate maximum blood pressure value can be obtained based on the amplitude ratio between the pulse waves. can get.

  According to the automatic blood pressure measurement device of the invention of claim 2, the amplitude ratio is obtained by dividing the amplitude value of the pulse wave from the predetermined inflation bag by the amplitude value of the pulse wave from the downstream inflation bag. Compression pressure of the compression band when the sequentially calculated amplitude ratio becomes smaller than a preset first amplitude ratio determination value in the process of decreasing the compression pressure value of the compression band that has been increased The value is determined as the maximum blood pressure value of the living body. Therefore, the state where the blood flow of the artery in the compressed region passes under the predetermined inflation bag but does not pass under the downstream inflation bag, and the blood flow of the artery in the compressed region is expanded under the predetermined inflation bag and downstream Distinguishing between the condition that passes under the bag and the blood pressure of the artery in the compressed area when passing through the specified inflation bag and the downstream inflation bag together. Since it is determined as the systolic blood pressure value, a highly accurate systolic blood pressure value is obtained.

  According to the automatic blood pressure measurement device of the invention according to claim 3, the compression band includes a pair of upstream inflatable bags made of a flexible sheet positioned at a predetermined interval in the longitudinal direction of the pressed portion, and the A downstream inflation bag is disposed between the upstream inflation bag and the downstream inflation bag so as to be continuous in the longitudinal direction of the compressed portion, and has an air chamber independent of the upstream inflation bag and the downstream inflation bag. Since it has an intermediate inflatable bag, it is compressed in the living body from the upstream inflatable bag, the intermediate inflatable bag, and the downstream inflatable bag that are connected in the longitudinal direction of the compressed portion and are in an independent state with respect to pressure fluctuation. An accurate pulse wave can be obtained by applying a compression pressure to the artery in the site with a uniform pressure distribution, so that a highly accurate maximum blood pressure value can be obtained based on the amplitude ratio between the pulse waves.

  According to the automatic blood pressure measurement device of the invention according to claim 4, the compressed pressure value of the compressed compression band is compressed by the upstream inflation bag, the intermediate inflation bag, and the downstream inflation bag. In the process of reducing the pressure in a state where the pressure is compressed with the same pressure, a value obtained by dividing the amplitude value of the pulse wave from the upstream inflation bag by the amplitude value of the pulse wave from the intermediate inflation bag is a preset second amplitude ratio. When the value obtained by dividing the amplitude value of the pulse wave from the intermediate expansion bag by the amplitude value of the pulse wave from the downstream expansion bag is smaller than the first amplitude ratio determination value. The compression pressure value of the intermediate expansion bag is determined as the maximum blood pressure value of the living body. Therefore, the blood flow of the artery in the compressed site passes under the upstream inflation bag but does not pass under the intermediate inflation bag and the downstream inflation bag, and the blood flow of the artery in the compressed site is upstream of the inflation bag. The blood flow of the artery in the compressed site is below the upstream inflation bag, below the intermediate inflation bag, and below the downstream inflation bag. Since the compression pressure value of the intermediate inflatable bag having a uniform pressure distribution in the width direction when they pass together is determined as the maximum blood pressure value of the living body, a highly accurate maximum blood pressure value can be obtained.

  In addition, according to the automatic blood pressure measurement device of the invention according to claim 5, the pressure sensor is provided with a pressure sensor for detecting the pressure in the plurality of inflatable bags, and the compression pressure values of the plurality of inflatable bags in the compression band wound around the compressed portion. In the process of increasing the pressure to a value sufficient for hemostasis of the artery in the compression site, and reducing the compression pressure value of the compression band, the compression pressure value of the compression band Since a pulse wave that is a pressure oscillation in the compression band is detected for a predetermined time and a pulse wave is detected when the compression pressure value is constant, an accurate pulse wave is obtained. be able to. In addition, when a plurality of pulse waves are detected within the predetermined time and the systolic blood pressure value is determined based on the average value of the plurality of pulse waves, a more accurate systolic blood pressure value is obtained.

1 shows an automatic blood pressure measurement device according to an example of the present invention, which includes an upper arm compression band wound around an upper arm that is a compressed portion of a living body. It is the figure which notched a part which shows the outer peripheral surface of the compression belt | band | zone of FIG. It is a top view which shows the upstream expansion bag, the intermediate | middle expansion bag, and the downstream expansion bag which were provided in the compression belt | band | zone of FIG. It is sectional drawing which cut | disconnects and shows the upstream expansion bag of FIG. 3, an intermediate | middle expansion bag, and a downstream expansion bag in the width direction. It is a functional block diagram for demonstrating the principal part of the control function with which the electronic control apparatus of FIG. 1 was equipped. FIG. 6 is a diagram showing pulse wave signals from the plurality of inflation bags generated in a process in which the compression pressure values of the plurality of inflation bags are respectively gradually reduced by the cuff pressure control means of FIG. 5, and the compression pressure value is 151 mmHg. It is a certain time. FIG. 6 is a diagram showing pulse wave signals from the plurality of expansion bags generated in the process of gradually decreasing the pressure values of the plurality of expansion bags by the cuff pressure control means of FIG. 5, wherein the compression pressure value is 135 mmHg. It is a certain time. FIG. 6 is a view showing pulse wave signals from the plurality of inflation bags generated in the process of gradually decreasing the pressure values of the plurality of inflation bags by the cuff pressure control means of FIG. 5, and the compression pressure value is 127 mmHg. It is a certain time. FIG. 6 is a diagram showing pulse wave signals from the plurality of inflation bags generated in a process in which the compression pressure values of the plurality of inflation bags are respectively gradually reduced by the cuff pressure control means of FIG. 5, and the compression pressure value is 110 mmHg. It is a certain time. FIG. 6 is a diagram showing pulse wave signals from the plurality of inflation bags generated in the process of gradually decreasing the pressure values of the plurality of inflation bags by the cuff pressure control means of FIG. 5, wherein the compression pressure value is 86 mmHg. It is a certain time. FIG. 6 is a diagram showing pulse wave signals from the plurality of inflation bags generated in the process in which the compression pressure values of the plurality of inflation bags are gradually reduced by the cuff pressure control means of FIG. 5, and the compression pressure value is 72 mmHg. It is a certain time. FIG. 6 is a diagram showing pulse wave signals from the plurality of inflation bags generated in the process of gradually decreasing the pressure values of the plurality of inflation bags by the cuff pressure control means of FIG. 5, wherein the compression pressure value is 58 mmHg. It is a certain time. FIG. 6 is a diagram showing pulse wave signals from the plurality of inflation bags generated in the process of gradually decreasing the pressure values of the plurality of inflation bags by the cuff pressure control means of FIG. 5, and the compression pressure value is 36 mmHg. It is a certain time. It is a figure which each shows the rising point of the pulse wave signal from the some expansion bag shown in the two-dimensional coordinate of a time axis and a compression pressure value axis, and the time difference between these rising points. It is a figure which shows the relationship between the pulse-wave propagation speed and compression pressure value in the artery under the compression by a compression zone. It is a figure which shows the relationship between the time difference between the pulse wave signals from a downstream expansion bag and an intermediate expansion bag, and the compression pressure value of a compression zone. It is one side of the flowchart explaining the principal part of control action of the electronic controller of FIG. It is the other of the flowchart explaining the principal part of the control action of the electronic controller of FIG. It is a time chart explaining the principal part of control action of the electronic controller of FIG. 5 shows an envelope (envelope) connecting the amplitude values of pulse wave signals from the plurality of inflation bags extracted in the process of gradually decreasing the pressure values of the plurality of inflation bags by the cuff pressure control means of FIG. FIG.

  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 modified, and the dimensional ratios, shapes, and the like of the respective parts are not necessarily drawn accurately.

  FIG. 1 shows an automatic blood pressure measurement device 14 according to an example of the present invention, which includes an upper arm compression band 12 wound around a living body limb, for example, an upper arm 10, which is a pressed part. This automatic blood pressure measurement device 14 is a pressure generated in response to a change in the volume of the artery 16 in the process of decreasing the compression pressure of the compression band 12 that has been increased to a value sufficient to stop the artery 16 in the upper arm 10. A pulse wave (see FIGS. 6 to 13 to be described later) that is pressure oscillation in the band 12 is sequentially extracted, and based on the change of the pulse wave, the maximum blood pressure value SBP and the minimum blood pressure value DBP of the living body are measured. is there.

  FIG. 2 is a partially cutaway view showing the outer peripheral surface of the compression band 12. As shown in FIG. 2, the compression band 12 includes a belt-shaped outer bag 20 made of a synthetic resin fiber outer circumferential side nonwoven fabric 20 a and a inner circumferential side nonwoven fabric (not shown) whose back surfaces are laminated with a synthetic resin such as PVC. An upstream inflatable bag 22, an intermediate inflatable bag 24, which are sequentially accommodated in the width direction within the belt-like outer bag 20 and are made of a flexible sheet such as a soft polyvinyl chloride sheet and can independently press the upper arm 10. A raised pile (not shown) attached to the end of the inner peripheral nonwoven fabric is detachably bonded to a hook and loop fastener 28 attached to the end of the outer peripheral side nonwoven fabric 20a. The upper arm 10 is detachably mounted. When attached to the upper arm 10, the downstream inflation bag 26 is positioned on the downstream side of the artery 16 in the upper arm 10 with respect to the upstream inflation bag 22 and the intermediate inflation bag 24. Further, the intermediate expansion bag 24 is positioned upstream of the downstream expansion bag 26, and the upstream expansion bag 22 is positioned upstream of the downstream expansion bag 26 and the intermediate expansion bag 24. The upstream inflatable bag 22, the intermediate inflatable bag 24, and the downstream inflatable bag 26 have independent air chambers that are connected in the width direction and press the upper arm 10 respectively, and have pipe connecting connectors 32, 34, and 36 is provided on the outer peripheral surface side. The pipe connecting connectors 32, 34, and 36 are exposed to the outer peripheral surface of the compression band 12 through the outer peripheral side nonwoven fabric 20a.

  3 is a plan view showing the upstream expansion bag 22, the intermediate expansion bag 24, and the downstream expansion bag 26 provided in the compression band 12, and FIG. 4 shows them in the width direction, that is, in the direction of arrow a in FIG. It is sectional drawing cut | disconnected. The upstream expansion bag 22, the middle flow expansion bag 24, and the downstream expansion bag 26 are for detecting a pulse wave that is pressure vibration generated in response to a volume change of the artery 16 compressed by them. , 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. Further, the intermediate expansion bag 24 is disposed at the center in the width direction of the compression band 12 while being sandwiched between the upstream expansion bag 22 and the downstream expansion bag 26. In the state where the compression band 12 is wound around the upper arm 10, 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 10, 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 10.

  The intermediate inflatable bag 24 has side edges of a so-called gusset structure on both sides. That is, at both ends in the longitudinal direction of the upper arm 10 of the intermediate inflatable bag 24, a pair of folding grooves 24f and 24f made of a flexible sheet folded in a direction approaching each other so as to become closer to each other are respectively provided. Is formed. The adjacent end portions 22a and 26a of the upstream expansion bag 22 and the downstream expansion bag 26 adjacent to the intermediate expansion bag 24 are inserted into the pair of folding grooves 24f and 24f. ing. Thereby, since both ends of the intermediate expansion bag 24 and the adjacent side end 22a of the upstream side expansion bag 22 and the adjacent side end 26a of the downstream side expansion bag 26 overlap each other, that is, an overlap structure, When the upstream expansion bag 22, the intermediate expansion bag 24, and the downstream expansion bag 26 press the upper arm 10 with equal pressure, a uniform pressure distribution is obtained even in the vicinity of the boundary.

  The upstream inflatable bag 22 and the downstream inflatable bag 26 also have side edges of a so-called gusset structure at the end portions 22 b and 26 b opposite to the intermediate inflatable bag 24. That is, the end portions 22b and 26b on the opposite side of the intermediate expansion bag 24 of the upstream expansion bag 22 and the downstream expansion bag 26 are flexibly folded in a direction approaching each other so as to become deeper as they approach each other. Folding grooves 22f and 26f made of a conductive sheet are respectively formed. The sheets constituting the folding grooves 22f and 26f are opposite to each other via connection sheets 38 and 40 having through holes arranged in the upstream expansion bag 22 and the downstream expansion bag 26 so as not to protrude in the width direction. It is connected to the side portion, that is, the portion on the intermediate expansion bag 24 side. As a result, the compression pressure on the artery 16 of the upper arm 10 can be obtained in the end portions 22b and 26b of the upstream expansion bag 22 and the downstream expansion bag 26 in the same manner as the other portions. The compression width is equivalent to the width dimension. The width direction of the compression band 12 is about 12 cm, and since the three upstream expansion bags 22, the intermediate expansion bag 24, and the downstream expansion bag 26 are arranged in the width direction, each is substantially 4 cm. It must be a width dimension of about. In order to generate a sufficient compression function even with such a narrow width dimension, both end portions 24a and 24b of the intermediate expansion bag 24 and adjacent end portions 22a and 26a of the upstream expansion bag 22 and the downstream expansion bag 26 are used. And end portions 22b and 26b of the upstream side expansion bag 22 and the downstream side expansion bag 26 opposite to the intermediate expansion bag 24 are side edges of a so-called gusset structure. Has been.

  Between the end portions 22a and 26a of the upstream expansion bag 22 and the downstream expansion bag 26 on the intermediate expansion bag 24 side, and the inner wall surfaces of the pair of folding grooves 24f and 24f into which they are inserted, that is, the opposite groove side surfaces In each, a longitudinal shielding member 42 having rigidity anisotropy in which the bending rigidity in the width direction of the compression band 12 is higher than the bending rigidity in the longitudinal direction of the compression band 12 is interposed. The shielding member 42 has the same length as the upstream expansion bag 22 and the downstream expansion bag 26 or the intermediate expansion bag 24. In this embodiment, as shown in FIGS. 3 and 4, the outer peripheral side gap among the gaps between the end 22 a of the upstream inflatable bag 22 and the folding groove 24 f into which it is inserted, and the downstream side Longitudinal shielding members 42 are interposed in the outer peripheral gaps among the gaps between the end portions 26a of the side expansion bags 26 and the folding grooves 24f into which the side expansion bags 26 are inserted. It may be interposed also in the gap. Since the outer circumferential side gap has a larger shielding effect than the inner circumferential side gap, it is sufficient to be provided at least in the outer circumferential side gap.

  The shielding member 42 includes a plurality of resin-made flexible hollow tubes 44 parallel to the longitudinal direction of the upper arm 10, that is, the width direction of the compression band 12, and the circumferential direction of the upper arm 10, that is, the compression band 12. The flexible hollow tubes 44 are connected to each other directly by molding or bonding, or indirectly through another member such as a flexible sheet such as an adhesive tape. Is configured. The shielding member 42 is latched by a plurality of latching sheets 46 provided at a plurality of positions on the outer peripheral side of the end portions 22a and 26a of the upstream inflation bag 22 and the downstream inflation bag 26 on the intermediate inflation bag 24 side. Yes.

  Returning to FIG. 1, in the automatic blood pressure measurement device 14, an air pump 50, a quick exhaust valve 52, and an exhaust control valve 54 are connected to the 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 connected to the downstream expansion bag 26. 64 is branched. The first branch pipe 58 includes a first on-off valve E1 in series for directly opening and closing between the air pump 50 and the upstream expansion bag 22. The main pipe 56 includes a second open / close valve E2 in series for directly opening and closing the air pump 50, the quick exhaust valve 52, the exhaust control valve 54, and the branch pipes. The third branch pipe 64 includes a third on-off valve E3 in series for directly opening and closing the space between the air pump 50 and the downstream expansion bag 26. A first pressure sensor T1 for detecting the pressure value in the upstream expansion bag 22 is connected to the first branch pipe 58, and a second pressure sensor T2 for detecting the pressure value in the intermediate expansion bag 24 is provided. A third pressure sensor T 3 connected to the second branch pipe 62 and detecting the pressure value in the downstream expansion bag 26 is connected to the third branch pipe 64.

  From the first pressure sensor T1, the second pressure sensor T2, and the third pressure sensor T3, an output indicating the pressure value in the upstream expansion bag 22, that is, the compression pressure value PC1 of the upstream expansion bag 22, is output to the electronic control unit 70. Output signal indicating the pressure value in the intermediate expansion bag 24, that is, the compression pressure value PC2 of the intermediate expansion bag 24, and output signal indicating the pressure value in the downstream expansion bag 26, that is, the compression pressure value PC3 of the downstream expansion bag 26. Are supplied respectively. The electronic control unit 70 is a so-called microcomputer including a CPU 72, a RAM 74, a ROM 76, an I / O port (not shown), and the like. In the electronic control unit 70, the CPU 72 processes input signals in accordance with a program stored in the ROM 76 in advance using the storage function of the RAM 74, and the electric air pump 50, the quick exhaust valve 52, the exhaust control valve 54, By controlling the first on-off valve E1, the second on-off valve E2, and the third on-off valve E3, respectively, in response to the volume change of the artery 16 of the upper arm 10 pressed against the expansion bags 22, 24, and 26, respectively. Pulse wave signals SM1, SM2, and SM3 (see FIGS. 6 to 13 described later) indicating pulse waves that are pressure vibrations in the generated expansion bags 22, 24, and 26 are collected. In addition, the electronic control unit 70 calculates the maximum blood pressure value SBP and the minimum blood pressure value DBP of the living body based on the pulse wave signals SM1, SM2, and SM3, and displays the measurement value that is the calculation result on the display device 78. Let In addition to the output signals from the first pressure sensor T1, the second pressure sensor T2, and the third pressure sensor T3, the electronic control device 70 is supplied with an output signal from the blood pressure measurement start sensor 80. The blood pressure measurement start sensor 80 outputs a signal serving as a cue for the start of blood pressure measurement. For example, the signal is output when an activation operation device (not shown) is operated.

  FIG. 5 is a functional block diagram for explaining the main part of the control function provided in the electronic control unit 70. In FIG. 5, the cuff pressure control means 82 is supplied with an air pump 50, a quick exhaust valve 52, an exhaust control valve 54, a first on-off valve when a signal serving as a cue to start blood pressure measurement is supplied from the blood pressure measurement start sensor 80. By controlling E1, the second on-off valve E2, and the third on-off valve E3, the compression pressure value PC applied to the artery 16 of the upper arm 10 by the expansion bags 22, 24, and 26 is changed to the maximum blood pressure value SBP in the artery 16. The pressure is rapidly increased simultaneously to a pressure increase target pressure value PCM (for example, 180 mmHg) that is set to a sufficiently higher value. For example, the pressure of each expansion bag is increased until the compression pressure value PC2 of the intermediate expansion bag 24 becomes equal to or higher than the pressure increase target pressure value PCM. Subsequently, the cuff pressure control means 82 gradually lowers the pressure values PC of the inflated bladders 22, 24, and 26, which have been boosted, at the same time at a preset step-down speed of, for example, 2 to 3 mmHg / sec. . At this time, the cuff pressure control means 82 holds the compression pressure value PC of the expansion bags 22, 24, and 26 for a predetermined time for each deceleration reduction of a predetermined amount (for example, within a range of 1 to 10 mmHg). Then, the cuff pressure control means 82 determines that the compression pressure value PC2 of the intermediate inflation bag 24 is lower than the measurement end pressure value PCE (for example, 30 mmHg) set in advance to a value sufficiently lower than the minimum blood pressure value DBP in the artery 16. When the pressure decreases, the quick exhaust valve 52 is used to exhaust the pressure in the expansion bags 22, 24, and 26 to atmospheric pressure.

  The amplitude determining unit 84 is configured to reduce the first pressure sensor T1, the second pressure sensor T2, and the third pressure sensor in the process in which the compression pressure value PC of the expansion bags 22, 24, and 26 is gradually decreased by the cuff pressure control unit 82, respectively. Based on an output signal from the pressure sensor T3, pulse wave signals SM1, SM2, and SM3 indicating pulse waves that are pressure fluctuations in the expansion bags 22, 24, and 26 are sequentially collected. 6 to 13 are diagrams illustrating the pulse wave signal SM generated in the above process. The pulse wave signals SM1, SM2, and SM3 shown in FIG. 6 to FIG. A pulse wave signal SM1 (broken line) indicating a pulse wave from the upstream expansion bag 22 obtained by discriminating the output signal from the first pressure sensor T1 by low-pass filter processing or band-pass filter processing; a second pressure sensor A pulse wave signal SM2 (solid line) indicating a pulse wave from the intermediate expansion bag 24 obtained by discriminating the output signal from T2 by low-pass filtering or band-pass filtering, and from the third pressure sensor T3 The output signal is lowpass filtered or bandpass filtered A pulse wave signal SM3 indicating a pulse wave from the downstream inflation bladder 26 obtained by the discrimination (one-dot chain line) by the. Then, the amplitude determining means 84 determines the amplitude values A1, A2, and A3 of the obtained pulse wave signals SM1, SM2, and SM3 for each beat, and sets the amplitude values A1 to A3 as the amplitude values A1. ~ A3 is stored in a predetermined storage area of the RAM 74 together with the cuff pressure signal PK2 indicating the compression pressure value PC2 of the intermediate expansion bag 24 corresponding to the determined pulse wave signal SM.

  The blood pressure value determining unit 86 determines the systolic blood pressure value SBP of the living body based on the amplitude ratio of the pulse wave signals from at least two of the plurality of inflatable bags 22, 24, and 26. It has. In this systolic blood pressure value determining means 88, while the compression pressure value PC is high, the difference in amplitude between the inflation bags is greatly different, but when the compression pressure value PC is near the systolic blood pressure value SBP, the inflation bags are in contact with each other. The systolic blood pressure value SBP is determined using the similarity in amplitude. Specifically, the systolic blood pressure value determining means 88, for example, uses the cuff pressure control means 82 to increase the compression pressure values PC of the inflatable bags 22, 24, and 26 by using the inflatable bags 22, 24, and 26. In the process of gradually decreasing the pressure while the parts 10 are compressed with the same pressure, the amplitude value A2 of the pulse wave signal SM2 from the intermediate expansion bag 24 is the amplitude value A3 of the pulse wave signal SM3 from the downstream expansion bag 26. The first amplitude ratio r23 (= A2 / A3), which is the divided value, is smaller than the first amplitude ratio determination value C1, and the amplitude value A1 of the pulse wave signal SM1 from the upstream expansion bag 22 is the intermediate expansion bag. 24 when the second amplitude ratio r12 (= A1 / A2), which is a value divided by the amplitude value A2 of the pulse wave signal SM2 from 24, becomes smaller than a preset second amplitude ratio determination value C2. Pressure of bag 24 Value PC2, determined as the systolic blood pressure value SBP of the living body.

  The vibration transmission level from the upstream expansion bag 22 to the intermediate expansion bag 24 of the compression band 12 of the present embodiment is, for example, about 30%. That is, when the amplitude value of the pressure vibration generated in the upstream expansion bag 22 is 1, the pressure vibration is transmitted to the intermediate expansion bag 24 and the amplitude value of the pressure vibration generated in the intermediate expansion bag 24 is about 0. 0. 3. The vibration transmission level from the intermediate expansion bag 24 to the downstream expansion bag 26 is, for example, about 30%. That is, when the amplitude value of the pressure vibration generated in the intermediate expansion bag 24 is 1, the pressure vibration is transmitted to the downstream expansion bag 26 and the amplitude value of the pressure vibration generated in the downstream expansion bag 26 is 0. 3 and the amplitude value of the pressure vibration generated in the upstream inflatable bag 22 is 1, the pressure vibration is transmitted to the downstream inflatable bag 26 via the intermediate inflatable bag 24 and the downstream inflatable bag. The amplitude value of the pressure vibration generated in the internal pressure 26 is about 0.09. Taking these into consideration, the first amplitude ratio determination value C1 is set to a value smaller than, for example, 3.33 by a predetermined value. For example, the second amplitude ratio determination value C2 is set to a value smaller than 3.33 by a predetermined value.

  In addition, the blood pressure value determining means 86 is configured to detect the phase difference between the pulse wave signals from at least two of the plurality of inflatable bags 22, 24, and 26 and the pulse wave propagation velocity in the artery 16 under compression by the compression band 12. There is provided a minimum blood pressure value determining means 90 for determining a minimum blood pressure value DBP of the living body based on PWV [m / sec]. Specifically, the diastolic blood pressure value determining means 90 compresses the upper arm portion 10 with the same pressure by the compressed pressure values PC of the inflated bags 22, 24, and 26, respectively. In the process in which the pressure is gradually reduced in each state, for example, the rising point of the pulse wave signal SM3 from the downstream expansion bag 26 shown in the two-dimensional coordinates of the time axis and the compression pressure value axis as shown in FIG. The first time difference t32 between a3 and the rising point a2 of the pulse wave signal SM2 from the intermediate expansion bag 24, and the rising point a2 and upstream side of the pulse wave signal SM2 from the intermediate expansion bag 24 shown in the two-dimensional coordinates A second time difference t21 from the rising point a1 of the pulse wave signal SM1 from the expansion bag 22 is sequentially calculated. The first time difference t32 and the second time difference t21 correspond to the phase difference.

  In the present embodiment, the rising point a1 is an intersection of the tangent line Lt1 at the inflection point b1 of the rising portion of the pulse wave signal SM1 and the horizontal line Lw1 parallel to the time axis passing through the rising start point c1 of the pulse wave signal SM1. . The rising point a2 is the intersection of the tangent line Lt2 at the inflection point b2 at the rising portion of the pulse wave signal SM2 and the horizontal line Lw2 parallel to the time axis passing through the rising start point c2 of the pulse wave signal SM2. The rising point a3 is the intersection of the tangent line Lt3 at the inflection point b3 of the rising portion of the pulse wave signal SM3 and the horizontal line Lw3 parallel to the time axis passing through the rising start point c3 of the pulse wave signal SM3.

In addition, the minimum blood pressure value determining means 90 is in a state where the compression pressure values PC of the boosted inflation bags 22, 24, and 26 press the upper arm 10 with the same pressure by the inflation bags 22, 24, and 26, respectively. In the process of gradually decreasing the pressure, the pulse wave propagation velocity PWV in the artery 16 under compression by the compression band 12 is sequentially calculated, and the rate of change R _PWV of the pulse wave propagation velocity PWV with respect to the compression pressure value PC2 of the intermediate inflation bag 24 is calculated. Calculate sequentially. The pulse wave velocity PWV is calculated by dividing the calculated first time difference t32 by the distance L32 (see FIG. 4) in the width direction between the intermediate expansion bag 24 and the downstream expansion bag 26. Further, the change rate R _PWV of pulse wave propagation velocity PWV is, for example, pulse-wave propagation velocity PWV and the compression pressure shown in the two-dimensional coordinates of the pressing pressure value axis and pulse wave velocity axis, as shown in FIG. 15 It is represented by the slope of the tangent of the curve indicating the relationship with the value PC2.

The minimum blood pressure value determining means 90 is in a state in which the pressure values PC of the inflated bladders 22, 24, and 26 that have been pressurized press the upper arm 10 with the same pressure by the inflating bags 22, 24, and 26. In the process of gradually decreasing the pressure, the first time difference t32 passes the preset time difference determination value tc, that is, smaller than the time difference determination value tc, and the second time difference t21 passes the time difference determination value tc. time difference determination value less than tc, and the change rate R _PWV pulse wave velocity PWV is accompanied by the change rate R _PWV as is continuously in compression pressure value PC2, as shown in FIG. 15 is increased from the lower limit value, for example zero In the increasing region b, the compression pressure value PC2 that passes through a preset change rate determination value Rc, that is, smaller than the change rate determination value Rc, It is determined as the lowest blood pressure value DBP. The time difference determination value tc corresponds to the phase difference determination value, the first time difference determination value, and the second time difference determination value in the present invention.

FIG. 15 is a diagram showing the relationship between the pulse wave propagation velocity PWV [m / sec] in the artery 16 under compression by the compression band 12 and the compression pressure value PC2 [mmHg]. As shown in FIG. 15, as the compression pressure value PC2 increases from zero, the pulse wave velocity PWV continuously decreases gradually from zero to near the minimum blood pressure value DBP and exceeds the minimum blood pressure value DBP. Then, it decreases rapidly and continuously in the vicinity, and then gradually decreases gradually toward the maximum blood pressure value SBP. That is, the pulse wave velocity PWV becomes slower as the compression pressure value PC2 becomes larger. Further, in the region indicated by the arrow b in the figure, the rate of change R _PWV (curve slope) of the pulse wave velocity PWV continuously increases as the compression pressure value PC2 increases from zero. The pulse wave propagation speed PWV1 when the compression pressure value PC2 matches the diastolic blood pressure value DBP varies depending on the measurement subject, but the change of the pulse wave propagation speed PWV when the compression pressure value PC2 matches the diastolic blood pressure value DBP. The rate R _PWV, that is, the change rate determination value Rc is the same value regardless of the person to be measured. The change rate determination value Rc is determined from the relationship shown in FIG.

  FIG. 16 is a diagram showing the relationship between the time difference between the pulse wave signals from the downstream expansion bag 26 and the intermediate expansion bag 24, that is, the first time difference t32, and the compression pressure value PC2. As shown in FIG. 16, the first time difference t32 corresponding to the pulse wave propagation time between the downstream expansion bag 26 and the intermediate expansion bag 24 is determined when the compression pressure value PC2 becomes the minimum blood pressure value DBP. The value is tc. The time difference determination value tc is determined from the relationship shown in FIG.

  17, 18 and 19 are a flowchart and a time chart for explaining the main part of the control operation of the electronic control unit 70. FIG. When a power switch (not shown) is turned on, the initial state shown at time t0 in FIG. In this state, since the first on-off valve E1, the second on-off valve E2, the third on-off valve E3, and the quick exhaust valve 52 are normally open valves, they are in an open state (non-operating state), and the exhaust control valve 54 is in a normal state. Since it is closed, it is in a closed state (non-operating state), and the air pump 50 is in a non-operating state.

  Next, when a startup operation device (not shown) is operated and the measurement operation of the automatic blood pressure measurement device 14 is started, first, the steps of FIG. 17 corresponding to the cuff pressure control means 82 (hereinafter, “step” is omitted). In S1, the compression pressure value of the compression band 12 is increased. Specifically, as shown in FIG. 19, while the quick exhaust valve 52 is closed, the air pump 50 is activated and compressed air pumped from the air pump 50 is fed into the main pipe 56 and to it. The pressure in the inflated bladders 22, 24, and 26 communicated is rapidly increased. Then, compression of the upper arm 10 by the compression band 12 is started.

  Subsequent to S1, in S2 corresponding to the cuff pressure control means 82, based on the cuff pressure signal PK2 indicating the compression pressure value PC2 of the intermediate inflatable bag 24, the compression pressure value PC2 is set in advance. It is determined whether or not the value is greater than or equal to value PCM (for example, 180 mmHg). At a time point before time t1 in FIG. 19, the determination in S2 is negative, and S1 and subsequent steps in FIG. 17 are repeatedly executed. However, at time t1 in FIG. 19, the determination in S2 is affirmed.

  If the determination in S2 is affirmative as described above, the operation of the air pump 50 is stopped in S3 corresponding to the cuff pressure control means 82. Then, the exhaust control valve 54 is configured so that the compression pressure values PC1, PC2, and PC3 of the boosted expansion bags 22, 24, and 26 are simultaneously reduced at a slow speed reduction rate that is set in advance to, for example, 2 to 3 mmHg / sec. Is activated and slow exhaust is started. At this time, the exhaust control valve 54 is controlled so that the pressure reduction amount of the compression pressure value PC of the expansion bags 22, 24, and 26 becomes a predetermined amount within a range of 1 to 10 mmHg, for example. The first on-off valve E1, the second on-off valve E2, and the third on-off valve E3 are operated so that the compression pressure value PC is held for a predetermined time. In order to hold the compression pressure value PC, the first on-off valve E1, the second on-off valve E2, and the third on-off valve E3 are closed. A time t2 in FIG. 19 is a start time of the slow exhaust, and a time t2 to a time t3 is a time during which the compression pressure value PC is held for a predetermined time.

  After S3, in S4 corresponding to the amplitude determining means 84, the first pressure sensor T1, the second pressure sensor T2, and the third pressure are maintained while the compression pressure values PC1, PC2, and PC3 are held for a predetermined time. Pulse waves from the expansion bags 22, 24, and 26 are obtained by performing low-pass filter processing or band-pass filter processing for discriminating signals in the wavelength band of several Hz to several tens of Hz from the output signal from the sensor T3. Are extracted, and the output signal from the second pressure sensor T2 is subjected to low-pass filter processing to compress the intermediate expansion bag 24 from which the AC component has been removed. A cuff pressure signal PK2 indicating the pressure value PC2 is extracted. They are stored in association with each other. 6 to 13 are diagrams illustrating the pulse wave signals SM1, SM2, and SM3 extracted and stored.

  In S4, each time the pulse wave signals SM1, SM2, and SM3 are obtained, the amplitude values A1 to A3 are determined for each beat, and the amplitude values A1 to A3 and the amplitude values A1 to A3 are determined. Based on the cuff pressure signal PK2 corresponding to the determined pulse wave signal SM, an envelope (envelope) connecting the amplitude values of the pulse wave signal as shown in FIG. 20, for example, is created and stored. In the envelope of FIG. 20, the value between each measurement point is obtained by curve interpolation, for example.

  Following S4, in S5 corresponding to the cuff pressure control means 82, while the compression pressure value PC is held for a predetermined time, based on the cuff pressure signal PK2 indicating the compression pressure value PC2 of the intermediate expansion bag 24. It is determined whether or not the compression pressure value PC is equal to or less than a preset measurement end pressure value PCE (for example, 30 mmHg). At a time point before time t11 in FIG. 19, the determination in S5 is negative, and S3 and subsequent steps in FIG. 17 are repeatedly executed. However, at time t11 in FIG. 19, the determination in S5 is affirmed.

  If the determination in S5 is affirmative as described above, the quick exhaust valve is set so that the pressure in the expansion bags 22, 24, and 26 is discharged to atmospheric pressure in S6 corresponding to the cuff pressure control means 82, respectively. 52 is activated. This state is shown after time t11 in FIG.

  After S6, in S7 corresponding to the systolic blood pressure value determining means 88, the compression pressure range of the envelope of FIG. 20 used for determining the systolic blood pressure value is limited to a lower limit value set in advance, for example, to about 100 mmHg. Is done.

  After S7, in S8 corresponding to the systolic blood pressure value determining means 88, when S8 is executed for the first time in this routine, the envelope of FIG. 20 is used and is the largest in the compression pressure range limited in S6. An amplitude value A1 of the pulse wave signal SM1 from the upstream inflation bag 22 corresponding to the measurement point having the compression pressure value PC2 is determined. Further, when S8 executed in this routine is the second time or later, the upstream side corresponding to a predetermined compression pressure value PC2 that is, for example, 1 mmHg smaller than the compression pressure value PC2 in the previous S8 by using the envelope of FIG. The amplitude value A1 of the pulse wave signal SM1 from the expansion bag 22 is determined.

  After S8, in S9 corresponding to the systolic blood pressure value determining means 88, when S9 is executed for the first time in this routine, the envelope in FIG. 20 is used and is the largest in the compression pressure range limited in S6. The amplitude value A2 of the pulse wave signal SM2 from the intermediate expansion bag 24 corresponding to the measurement point having the compression pressure value PC2 is determined. Further, when S9 executed in this routine is the second time or later, the intermediate expansion corresponding to a predetermined compression pressure value PC2 that is, for example, 1 mmHg smaller than the compression pressure value PC2 in the previous S9 using the envelope of FIG. An amplitude value A2 of the pulse wave signal SM2 from the bag 24 is determined.

  After S9, in S10 corresponding to the systolic blood pressure value determining means 88, when S10 is executed for the first time in this routine, the envelope in FIG. 20 is used and is the largest in the compression pressure range limited in S6. The amplitude value A3 of the pulse wave signal SM3 from the downstream expansion bag 26 corresponding to the measurement point having the compression pressure value PC2 is determined. Further, when S10 executed in this routine is the second time or later, the downstream side corresponding to a predetermined compression pressure value PC2 that is, for example, 1 mmHg smaller than the compression pressure value PC2 in the previous S10 by using the envelope of FIG. The amplitude value A3 of the pulse wave signal SM3 from the expansion bag 26 is determined.

  Following S10, in S11 corresponding to the systolic blood pressure value determining means 88, the amplitude value A2 of the pulse wave signal SM2 from the intermediate inflation bag 24 based on the amplitude values A1 to A3 determined in the immediately preceding S8 to S10. Is divided by the amplitude value A3 of the pulse wave signal SM3 from the downstream expansion bag 26, a first amplitude ratio r23 is calculated. Further, a second amplitude ratio r12 that is a value obtained by dividing the amplitude value A1 of the pulse wave signal SM1 from the upstream expansion bag 22 by the amplitude value A2 of the pulse wave signal SM2 from the intermediate expansion bag 24 is calculated.

  Following S11, in S12 corresponding to the systolic blood pressure value determining means 88, the first amplitude ratio r23 calculated in the immediately preceding S11 is smaller than the preset first amplitude ratio determination value C1, and the immediately preceding It is determined whether or not the second amplitude ratio r12 calculated in S11 is smaller than a preset second amplitude ratio determination value C2.

  If the determination in S12 is negative, S8 and subsequent steps are repeatedly executed. If the determination in S12 is affirmative, in S13 corresponding to the systolic blood pressure value determining means 88, the compression pressure value PC2 in S9 at that time is determined as the maximal blood pressure value SBP of the living body.

  Following S13, in S14 of FIG. 18 corresponding to the diastolic blood pressure determining means 90, the envelope compression pressure range of FIG. 20 used for determining the diastolic blood pressure value is, for example, an upper limit set in advance to about 100 mmHg. It is limited to the following.

  After S14, in S15 corresponding to the minimum blood pressure value determining means 90, when S15 is first executed in this routine, it is the largest in the compression pressure range limited in S14 in the envelope of FIG. Based on the pulse wave signal SM1 from the upstream expansion bag 22 corresponding to the measurement point having the compression pressure value PC2, the time ta1 of the rising point a1 of the pulse wave signal SM1 is determined. This time ta1 is the time from the start of blood pressure measurement. Further, when S15 executed in this routine is the second time or later, the pulse from the upstream inflating bag 22 corresponding to the measurement point having the compression pressure value PC2 that is the second smallest after the compression pressure value PC2 in the previous S15. Based on the wave signal SM1, the time ta1 of the rising point a1 of the pulse wave signal SM1 is determined.

  Following S15, in S16 corresponding to the minimum blood pressure value determining means 90, when S16 is first executed in this routine, the envelope of FIG. 20 is the most within the compression pressure range limited in S13. Based on the pulse wave signal SM2 from the intermediate expansion bag 24 at the measurement point having the large compression pressure value PC2, the time ta2 of the rising point a2 of the pulse wave signal SM2 is determined. This time ta2 is the time from the start of blood pressure measurement. In addition, when S16 executed in this routine is the second time or later, the pulse wave from the intermediate expansion bag 24 corresponding to the measurement point having the compression pressure value PC2 that is the second smallest after the compression pressure value PC2 in the previous S16. Based on the signal SM2, a time ta2 of the rising point a2 of the pulse wave signal SM2 is determined.

  After S16, in S17 corresponding to the minimum blood pressure value determining means 90, when S17 is first executed in this routine, the envelope of FIG. 20 is the most within the compression pressure range limited in S13. Based on the pulse wave signal SM3 from the downstream inflation bag 26 at the measurement point having the large compression pressure value PC2, the time ta3 of the rising point a3 of the pulse wave signal SM3 is determined. This time ta3 is the time from the start of blood pressure measurement. Further, when S17 executed in this routine is the second time or later, the pulse from the downstream inflatable bag 26 corresponding to the measurement point having the compression pressure value PC2 that is the second smallest after the compression pressure value PC2 in the previous S17. Based on the wave signal SM3, the time ta3 of the rising point a3 of the pulse wave signal SM3 is determined.

Following S17, in S18 corresponding to the diastolic blood pressure value determining means 90, based on the time ta1 to ta3 determined in the immediately preceding S15 to S17, a second time difference t21 (from the difference between the time ta2 and the time ta1). = Ta2-ta1), and the first time difference t32 (= ta3-ta2) is calculated from the difference between the time ta3 and the time ta2. Further, the pulse wave propagation velocity PWV is calculated by dividing the calculated first time difference t32 by the distance in the width direction between the intermediate expansion bag 24 and the downstream expansion bag 26, and as shown in FIG. From the slope of the tangent line of the curve indicating the relationship between the pulse wave velocity PWV and the compression pressure value PC2 shown in the two-dimensional coordinates of the compression pressure value axis and the pulse wave velocity axis, the compression pressure value of the intermediate expansion bag 24 A rate of change R _PWV of the pulse wave velocity PWV with respect to PC2 is calculated.

Following S18, in S19 corresponding to the diastolic blood pressure value determining means 90, the first time difference t32 is smaller than the preset time difference determination value tc, and the second time difference t21 is smaller than the time difference determination value tc. and pulse-wave propagation velocity PWV rate of change R _PWV is, in a region where with by the change rate R _PWV continuously increases the compression pressure value PC2, as shown by the arrow b in FIG. 15 is increased from the lower limit value, for example zero It is determined whether or not the change rate determination value Rc is smaller than a preset value.

  If the determination in S19 is negative, S15 and subsequent steps are repeatedly executed. If the determination in S19 is affirmative, in S20 corresponding to the minimum blood pressure value determining means 90, the compression pressure value PC2 of the intermediate expansion bag 24 corresponding to the pulse wave signal SM2 used in the immediately preceding S16. Based on the compression pressure value PC2 ′ of the intermediate inflation bag 24 corresponding to the pulse wave signal SM2 ′ used in S16 executed immediately before S16 immediately before, the minimum blood pressure of the living body is obtained by linear interpolation. The value DBP is determined.

  In S21, the maximum blood pressure value SBP and the minimum blood pressure value DBP of the living body are displayed on the display device 78, and this routine is terminated.

  According to the automatic blood pressure measurement device 14 of the present embodiment, the compression band 12 is connected to the width direction and has a plurality of inflatable bags 22 and 24 each having an independent air chamber that compresses the upper arm 10 that is a compressed portion of the living body. , And 26, and the amplitude value A3 of the pulse wave signal SM3 from the downstream inflation bag 26 located downstream of the artery 16 in the upper arm 10 of the inflation bags 22, 24, and 26, and A first amplitude ratio r23, which is an amplitude ratio with the amplitude value A2 of the pulse wave signal SM2 from the intermediate expansion bag (predetermined expansion bag) 24 located upstream of the downstream expansion bag 26, is sequentially calculated, Since the maximum blood pressure value SBP of the living body is determined based on the first amplitude ratio r23, the arteries 16 of the upper arm 10 are transferred from the plurality of inflatable bags 22, 24, and 26 that are independent of each other in terms of pressure fluctuation. Compression pressure is even pressure Since accurate pulse-wave signal SM by adding a cloth is obtained, a high systolic blood pressure SBP accuracy is obtained based on the amplitude ratio between these pulse wave signal SM.

  Further, according to the automatic blood pressure measurement device 14 of the present embodiment, the first amplitude ratio r23 is obtained by changing the amplitude value A2 of the pulse wave signal SM2 from the intermediate expansion bag 24 to the pulse wave signal SM3 from the downstream expansion bag 26. The first amplitude ratio r23, which is a value divided by the amplitude value A3 and is sequentially calculated in the process of decelerating and decreasing the compression pressure value PC of the pressure band 12 that has been increased, is determined from the preset first amplitude ratio determination value C1. The compression pressure value PC of the intermediate inflatable bag 24 when it becomes smaller is determined as the maximum blood pressure value SBP of the living body. Therefore, a state in which the blood flow of the artery 16 in the upper arm 10 passes under the intermediate inflation bag 24 but does not pass under the downstream inflation bag 26 and a state where the blood flow passes through both the intermediate inflation bag 24 and the downstream inflation bag 26 together. Distinguishing, the compression pressure value PC2 of the intermediate inflation bag 24 when the blood flow of the artery 16 in the upper arm 10 passes both under the intermediate inflation bag 24 and under the downstream inflation bag 26 is the maximum blood pressure value SBP of the living body. Therefore, a highly accurate systolic blood pressure value SBP is obtained.

  Further, according to the automatic blood pressure measurement device 14 of the present embodiment, the compression band 12 includes a pair of upstream expansion bags 22 and a downstream expansion that are made of a flexible sheet that is positioned at a predetermined interval in the longitudinal direction of the upper arm 10. An air chamber is disposed between the upstream inflatable bag 22 and the downstream inflatable bag 26 so as to be continuous with the bag 26 in the longitudinal direction of the upper arm 10, and is independent of the upstream inflatable bag 22 and the downstream inflatable bag 26. Since the intermediate expansion bag 24 includes the upstream expansion bag 22, the intermediate expansion bag 24, and the downstream expansion bag 26 that are continuous in the longitudinal direction of the upper arm 10 and are in an independent state with respect to pressure fluctuation. Since an accurate pulse wave is obtained by applying a compression pressure to the artery 16 in the upper arm 10 with an even pressure distribution, a highly accurate systolic blood pressure value SBP is obtained based on the amplitude ratio between the pulse waves. .

  Further, according to the automatic blood pressure measurement device 14 of the present embodiment, the pressure values PC1, PC2, and PC3 of the upstream inflatable bag 22, the intermediate inflatable bag 24, and the downstream inflatable bag 26 that have been boosted are used as the inflatable bags. In the process of lowering the pressure of the upper arm 10 with the same pressure, the second is a value obtained by dividing the amplitude value A1 of the pulse wave from the upstream expansion bag 22 by the amplitude value A2 of the pulse wave from the intermediate expansion bag 24. Is a value obtained by dividing the amplitude value A2 of the pulse wave from the intermediate expansion bag 24 by the amplitude value A3 of the pulse wave from the downstream expansion bag 26. The compression pressure value PC2 of the intermediate expansion bag 24 when the first amplitude ratio r23 becomes smaller than the first amplitude ratio determination value C1 is determined as the maximum blood pressure value SBP of the living body. Therefore, the blood flow of the artery 16 in the upper arm 10 passes under the upstream inflation bag 22 but does not pass under the intermediate inflation bag 24 and the downstream inflation bag 26, and under the upstream inflation bag 22 and the intermediate inflation bag 24. The blood flow of the artery 16 in the upper arm 10 is divided under the upstream inflation bag 22, the intermediate inflation bag 24, and the downstream inflation bag 26 together. Since the compression pressure value PC2 of the intermediate inflatable bag 24, which has a uniform pressure distribution in the width direction when it passes, is determined as the maximum blood pressure value SBP of the living body, a highly accurate maximum blood pressure value SBP is obtained. .

  Further, according to the automatic blood pressure measurement device 14 of the present embodiment, the pressure band T1, T2, and T3 that detects the pressure in the plurality of inflatable bags 22, 24, and 26, and is wound around the upper arm 10 In the process of boosting the pressure values PC of the twelve inflatable bags 22, 24 and 26 to a value sufficient to stop the artery 16 in the upper arm 10 and then simultaneously lowering the pressure values PC respectively For example, each compression pressure value PC is held for a predetermined time every predetermined amount of deceleration pressure reduction within a range of 1 to 10 mmHg, and a pulse wave which is pressure vibration in the expansion bags 22, 24, and 26 within the predetermined time. Since the detected pulse wave signals SM1, SM2, and SM3 are detected, each pulse wave signal SM1, SM2, and SM3 is detected when each compression pressure value PC is constant. SM1, SM2, and SM3 can be obtained.

  As mentioned above, although one Example of this invention was described in detail with reference to drawings, this invention is not limited to this Example, It can implement in another aspect.

  For example, the boost target pressure value PCM and the measurement end pressure value PCE are not necessarily set in advance. For example, based on the previously measured systolic blood pressure value SBP and the diastolic blood pressure value DBP input by the operator after the power switch of the automatic blood pressure measuring device 14 is turned on, the input systolic blood pressure value SBP has a predetermined value (for example, 30 mmHg). ) May be set to the pressure increase target pressure value PCM, and the measurement end pressure value PCE may be set to a value obtained by subtracting a predetermined value (for example, 30 mmHg) from the input minimum blood pressure value DBP. Alternatively, during the rapid pressure increase by the cuff pressure control means 82 (between times t1 and t2 in FIG. 18), for example, the pulse wave signal SM2 from the intermediate expansion bag 24 is extracted to create an envelope, and well known based on the envelope. The maximal blood pressure value SBP and the diastolic blood pressure value DBP of the living body are predicted according to the oscillometric algorithm, and the boost target pressure value PCM is a value obtained by adding a predetermined value (for example, 20 mmHg) to the predicted maximal blood pressure value SBP. The measurement end pressure value PCE may be set to a value obtained by subtracting a predetermined value (for example, 20 mmHg) from the predicted minimum blood pressure value DBP.

  Further, during the gradual pressure reduction process by the cuff pressure control means 82, while the compression pressure value PC of the expansion bags 22, 24, and 26 is maintained for a predetermined time, the amplitude determination means 84 causes the expansion bags 22, 24, and 26 to be maintained. A plurality of beat wave signals SM1, SM2, and SM3 may be sampled, and a systolic blood pressure value SBP and a diastolic blood pressure value DBP may be determined based on an average value of the pulse wave signals SM corresponding to the multiple pulses. In this case, a more accurate blood pressure value can be obtained.

  Moreover, although the value between each measurement point was calculated | required by curve complementation for the envelope (envelope) created in S4 of FIG. 16, it may be supplemented, for example by linear complementation or other well-known complementing methods.

  In addition, when determining the systolic blood pressure value SBP, the systolic blood pressure value determining unit 88 does not necessarily need to use both the first amplitude ratio r23 and the second amplitude ratio r12. The amplitude obtained from at least the downstream expansion bag 26 may be used. For example, the compression pressure of the intermediate expansion bag 24 when the first amplitude ratio r23 becomes smaller than a preset first amplitude ratio determination value C1. The value PC2 may be determined as the maximum blood pressure value SBP of the living body.

  The amplitude ratio used when determining the systolic blood pressure value SBP does not necessarily have to be the first amplitude ratio r23. The amplitude of the pulse wave signal SM1 from the upstream inflation bag 22 is not necessarily used. The value may be a third amplitude ratio r13 that is a value obtained by dividing the value A1 by the amplitude value A3 of the pulse wave signal SM3 from the downstream expansion bag 26, or the reciprocal of the first amplitude ratio r23 or the second amplitude ratio r13. There may be.

  Further, when determining the minimum blood pressure value DBP, the minimum blood pressure value determining unit 90 does not necessarily need to use both the first time difference t32 and the second time difference t21. At least the first time difference t32, the second time difference t21, and the time difference between the rising point a3 of the pulse wave signal SM3 from the downstream expansion bag 26 and the rising point a1 of the pulse wave signal SM1 from the upstream expansion bag 22. One of the three time differences t31 may be used. For example, the compression pressure value PC of the intermediate expansion bag 24 when the first time difference t32 becomes smaller than a preset time difference determination value tc The minimum blood pressure value DBP may be determined.

  Further, the phase difference used when the diastolic blood pressure value determining means 90 determines the diastolic blood pressure value DBP is not necessarily the rising point a3 of the pulse wave signal SM3 from the downstream inflation bag 26 and the pulse wave from the downstream inflation bag 26. It may not be the time difference (first time difference t32) from the signal SM3 rising point a2. For example, it may be a time difference between the inflection point b3 and the inflection point b2, or a time difference between the rising point c3 and the rising point c2. Alternatively, it may be a difference between another point of the pulse wave signal SM3 from the downstream expansion bag 26 and another point of the pulse wave signal SM3 from the downstream expansion bag 26.

Further, when determining the minimum blood pressure value DBP, the minimum blood pressure value determining unit 90 does not necessarily need to use both the rate of change R _PWV of the pulse wave velocity _PWV and the first time difference t32 and the second time difference t21. Absent. Change rate and _{R PWV} pulse wave velocity PWV, it may be used any one of the first time difference t32 or third time difference t31. For example, the minimum blood pressure value determining unit 90 passes the first time difference t32 through the preset time difference determination value tc in the process of lowering the compression pressure value PC2 of the compression band 12, that is, smaller than the time difference determination value tc. The compression pressure value PC2 when the second time difference t21 passes the time difference determination value tc, that is, becomes smaller than the time difference determination value tc, may be determined as the minimum blood pressure value DBP of the living body. In this way, an accurate pulse wave signal can be obtained by applying compression pressure to the artery 16 of the upper arm 10 from the plurality of inflatable bags 22, 24, and 26 that are in an independent state with respect to pressure fluctuation. Since each SM is obtained, a highly accurate minimum blood pressure value DBP is obtained based on the phase difference between the pulse wave signals SM. Further, for example, the minimum blood pressure value determining means 90, in the process of lowering the compression pressure value PC2 of the compression band 12, the rate of change R _PWV of the pulse wave velocity PWV is lower than the compression pressure value PC2 as shown in FIG. In the region b where the change rate R _PWV continuously increases as the value increases from zero, for example, the compression pressure value when passing through the preset change rate determination value Rc, that is, smaller than the change rate determination value Rc The PC2 may be configured to determine the diastolic blood pressure DBP of the living body. In this way, the pulse wave velocity PWV becomes slower as the compression pressure value PC2 increases, and the rate of change R _PWV of the pulse wave velocity PWV with respect to the compression pressure value PC2 is the lowest blood pressure value of the living body regardless of the subject. Since the diastolic blood pressure value DBP is determined using the fact that it changes rapidly in the region near the DBP, a highly accurate diastolic blood pressure value DBP is obtained.

  Further, at the time of blood pressure measurement, it is not always necessary to step down the compression pressure value PC stepwise at a preset slow speed reduction rate after the pressure is raised to the pressure increase target pressure value PCM. That is, the compression pressure value PC may be continuously reduced. Alternatively, the deceleration pressure reduction may be performed only in the vicinity of the blood pressure value measurement, and the measurement time may be shortened by rapid pressure reduction in the other sections. For example, first, every time the pulse wave signals SM1, SM2, and SM3 from the expansion bags 22, 24, and 26 are extracted in the gradual pressure reduction process after the pressure is increased to the pressure increase target pressure value PCM, the envelope shown in FIG. A part is created and S8 to S12 of FIG. 17 are executed to determine the systolic blood pressure value SBP. Subsequently, after the determination of the maximum blood pressure value SBP, the compression pressure value PC is rapidly lowered to a pressure value that is larger than a predicted minimum blood pressure value DBP ′ by a predetermined amount (for example, 30 mmHg). Thereby, measurement time can be shortened. The predicted diastolic blood pressure value DBP ′ is obtained by, for example, extracting the pulse wave signal SM2 from the intermediate inflation bag 24 during the rapid pressure increase (between times t1 and t2 in FIG. 19) by the cuff pressure control means 82. An envelope is created and predicted according to a well-known oscillometric algorithm based on the envelope.

  In the above-described embodiment, the blood pressure value is determined in the process in which the compression pressure in the compression band 12 is decreased. However, the present invention is not limited to this, and the process in which the compression pressure in the compression band 12 is increased. The pressurization measurement for determining the blood pressure value may be performed. In such a pressure increase measurement, the above-described systolic blood pressure value determination algorithm and diastolic blood pressure value determination algorithm can be used, and similar effects can be obtained.

  Moreover, the expansion bag with which the compression belt 12 is provided is not limited to three, and may be four or more.

  It should be noted that the above description is merely an embodiment, and other examples are not illustrated. However, the present invention is implemented in variously modified and improved modes based on the knowledge of those skilled in the art without departing from the gist of the present invention. Can do.

10: Upper arm (stressed part)
12: compression band 14: automatic blood pressure measurement device 16: artery 22: upstream inflation bag (inflation bag)
24: Intermediate expansion bag (expansion bag)
26: Downstream expansion bag (expansion bag)
A1, A2, A3: Amplitude value DBP: Minimum blood pressure value (blood pressure value)
PC1, PC2, PC3: compression pressure value PCM: pressure increase target pressure value (a value sufficient to stop the artery)
R1: First amplitude ratio determination value R2: Second amplitude ratio determination value SBP: Maximum blood pressure value (blood pressure value)
SM1, SM2, SM3: Pulse wave signal (pulse wave)
T1: First pressure sensor T2: Second pressure sensor T3: Third pressure sensor r12: Second amplitude ratio r23: First amplitude ratio

Claims (5)

A compression band wound around the compressed portion of the living body, and in the process of changing the compression pressure value of the compression band, pulse waves that are pressure vibrations in the compression band are sequentially extracted, and based on the change of the pulse wave, An automatic blood pressure measuring device for determining a blood pressure value of a living body,
The compression band has a plurality of inflatable bags having independent air chambers that are linked in the width direction and respectively compress the compressed portion of the living body.
Among the plurality of inflation bags, the amplitude value of the pulse wave from the downstream inflation bag located on the downstream side of the artery in the compressed site, and a predetermined inflation bag located on the upstream side of the downstream inflation bag An automatic blood pressure measurement device that sequentially calculates an amplitude ratio with an amplitude value of a pulse wave from the blood pressure and determines a maximum blood pressure value of the living body based on the amplitude ratio. The amplitude ratio is a value obtained by dividing the amplitude value of the pulse wave from the predetermined expansion bag by the amplitude value of the pulse wave from the downstream expansion bag,
In the process of decreasing the compression pressure value of the compressed compression band, the compression pressure value of the compression band when the sequentially calculated amplitude ratio becomes smaller than a preset first amplitude ratio determination value, 2. The automatic blood pressure measuring device according to claim 1, wherein the automatic blood pressure measuring device is determined as a maximum blood pressure value of the living body.   The compression band is continuous with a pair of upstream inflatable bags and a downstream inflatable bag made of a flexible sheet positioned at a predetermined interval in the longitudinal direction of the compressed portion, in the longitudinal direction of the compressed portion. And an intermediate expansion bag having an air chamber that is disposed between the upstream expansion bag and the downstream expansion bag and has an air chamber independent of the upstream expansion bag and the downstream expansion bag. The automatic blood pressure measuring device according to claim 1 or 2.   In the process of lowering the pressure value of the pressure band that has been increased in the process of lowering the compressed portion with the same pressure by the upstream inflation bag, the intermediate inflation bag, and the downstream inflation bag, the intermediate inflation The amplitude ratio obtained by dividing the amplitude value of the pulse wave from the bag by the amplitude value of the pulse wave from the downstream expansion bag is smaller than the first amplitude ratio determination value, and the pulse wave from the upstream expansion bag is The compression pressure value of the intermediate expansion bag when the amplitude ratio obtained by dividing the amplitude value by the amplitude value of the pulse wave from the intermediate expansion bag is smaller than a preset second amplitude ratio determination value, 4. The automatic blood pressure measuring device according to claim 3, wherein the automatic blood pressure measuring device is determined as a maximum blood pressure value. A pressure sensor for detecting pressure in the plurality of expansion bags;
After increasing the pressure value of the plurality of inflatable bags of the compression band wound around the compression site to a value sufficient to stop the artery in the compression site, the compression pressure value of the compression band is In the process of depressurization, the compression pressure value of the compression band is held for a predetermined time every predetermined amount of deceleration pressure reduction, and a pulse wave that is pressure vibration in the compression band is detected within the predetermined time. The automatic blood pressure measuring device according to any one of claims 1 to 4.

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