JP6888212B2 - Blood pressure measuring device - Google Patents

Description

The present invention relates to a blood pressure measuring device that measures blood pressure by measuring Korotkoff sounds generated during ischemia of an artery.

At the time of blood pressure measurement, blood flow is resumed when the compression pressure of the artery becomes equal to the blood pressure in the artery by gradually relaxing the compression pressure of the artery after blocking blood by pumping air into the cuff and compressing the artery. This produces a Korotkoff sound, which is an arterial flow sound. This Korotkoff sound increases with increasing blood flow by further relaxing the pressure on the artery. It is said that the intensity of such Korotkoff sounds reflects the blood flow rate, and the intensity change pattern of the Korotkoff sounds reflects the functions of the heart and vascular system.

By the way, in order to measure Korotkoff sounds at a plurality of sites in blood pressure measurement, it is desirable to compress blood vessels at a plurality of sites with the same pressure and compare the state of blood flow at the same heart contraction with the Korotkoff sounds. However, since the conventional device for measuring Korotkoff sounds has a configuration in which the microphone is directly applied to the arteries of the arm or foot to measure, in order to avoid interference of a plurality of Korotkoff sounds obtained by simultaneously measuring a plurality of parts. In addition, the measurement time is staggered for each part and the measurement is performed independently.

Therefore, the applicant has developed a Korotkoff sound measuring device capable of measuring Korotkoff sounds due to the same contraction of the heart at a plurality of sites (see, for example, Patent Document 1). FIG. 8 is a block diagram schematically showing the configuration of a conventional Korotkoff sound measuring device. As shown in FIG. 8, the conventional Korotkoff sound measuring device includes a plurality of Korotkoff sound measuring sac 2A and 2B for measuring the Korotkoff sound generated when the artery is compressed, and a plurality of Korotkoff sound measuring sac 2A and 2B. For arterial compression, which is connected one by one via conduits 1C and 1D, and each is connected via pressure supply pipes 1E and 1F, and is pressurized via pressure supply pipes 1E and 1F to compress the artery. It is provided with caps 1A and 1B and microphones 3A and 3B connected to caps 2A and 2B for measuring Korotkoff sounds.

In this Korotkoff sound measuring device, when the Korotkoff sounds based on the same contraction of the heart measured at a plurality of sites by the Korotkoff sound measuring sac 2A and 2B propagate to the arterial compression sac 1A and 1B, the sound is lowered to a predetermined level or less. By setting the opening area of the conduits 1C and 1D so as to attenuate, even if Korotkoff sounds interfere between the arterial compression capsules 1A and 1B, the interference interferes with the measurement of Korotkoff sounds by the microphones 3A and 3B. It is possible to measure Korotkoff sounds based on the same contraction of the heart measured at multiple sites with high accuracy.

Japanese Unexamined Patent Publication No. 2003-290157

In the conventional Korotkoff sound measuring device, the Korotkoff sounds based on the same contraction of the heart measured at a plurality of sites are measured by attaching the arterial compression sac 1A and 1B to the body at a plurality of sites, respectively. In this device, it is necessary to wear all of the plurality of arterial compression capsules 1A and 1B on the body for measurement. That is, in this device, since a plurality of arterial compression sac 1A and 1B are always pressurized at the same time through the pressure supply pipe 1E, it is not possible to attach only one of the arterial compression sac 1A for measurement. If only one arterial compression sac 1A is attached and pressurized, pressurized air is also supplied to the non-attached arterial compression sac 1B, which is sufficient for the arterial compression sac 1A on the side to be measured. Pressurized air will not be supplied.

Therefore, in the present invention, it is possible to measure the Korotkoff sounds based on the same contraction of the heart measured at a plurality of sites, and it is possible to measure the blood pressure by measuring the Korotkoff sounds even at only a part of the blood pressure. It is an object of the present invention to provide a measuring device.

The blood pressure measuring device of the present invention is a plurality of arterial compression sac that is attached to a plurality of measurement sites to compress an artery, and a plurality of Korotkoff sound measurement sac for measuring the Korotkoff sound generated when the artery is compressed. , Multiple Korotkoff sound measurement sac connected to multiple arterial compression sac via conduits, multiple microphones connected to multiple Korotkoff sound measurement sac, and multiple arterial compression sac Multiple pressure supply pipes connected to the sac, multiple electromagnetic air valves provided in the middle of the multiple pressure supply pipes, and multiple arterial compression sac by opening and closing each of the multiple electromagnetic air valves at the same time. Or, it has a control means that can pressurize and depressurize only a specific arterial compression sac.

In the blood pressure measuring device of the present invention, it is possible to pressurize and depressurize a plurality of arterial compression sac at the same time or only a specific arterial compression sac by opening and closing a plurality of electromagnetic air valves. By switching the opening and closing of multiple electromagnetic air valves, it is possible to select simultaneous measurement at multiple points or individual measurement.

Here, the control means may open a plurality of electromagnetic air valves to measure the blood pressure of a plurality of measurement sites at the same time, and then open only a specific electromagnetic air valve to measure the blood pressure of a specific measurement site. desirable. This makes it possible to automatically and continuously measure a specific part independently after simultaneous measurement of a plurality of parts.

(1) A plurality of arterial compression sac that is attached to a plurality of measurement sites to compress an artery, and a plurality of Korotkoff sound measurement sac for measuring Korotkoff sounds generated when an artery is compressed, and a plurality of arterial compressions. A plurality of Korotkoff sound measurement sac connected to each sac via a conduit, a plurality of microphones connected to each of a plurality of Korotkoff sound measurement sac, and a plurality of arterial compression sac respectively. Multiple pressure supply pipes, multiple electromagnetic air valves provided in the middle of the plurality of pressure supply pipes, and multiple electromagnetic air valves can be opened and closed to open and close multiple arterial compression sacs at the same time or to a specific artery. According to a blood pressure measuring device having a control means capable of pressurizing and depressurizing only the compression sac, it is possible to measure Korotkoff sounds based on the same contraction of the heart measured at multiple sites, and even only a part of the heart. It is possible to measure the blood pressure by measuring the Korotkoff sounds.

(2) The control means is to open a plurality of electromagnetic air valves to measure the blood pressure of a plurality of measurement sites at the same time, and then open only a specific electromagnetic air valve to measure the blood pressure of a specific measurement site. , After simultaneous measurement of a plurality of points, it is possible to automatically and continuously perform independent measurement of a specific site.

It is a block diagram which shows schematic structure of the blood pressure measuring apparatus in embodiment of this invention. It is the schematic which shows the main part of the blood pressure measuring apparatus of FIG. 1 enlarged. It is a characteristic diagram which shows the compression pressure by a cuff and Korotkoff sound at the time of blood pressure measurement. It is a characteristic diagram which shows the Korotkoff sound which shows the relationship between the compression pressure by a cuff and the Korotkoff sound after half-wave detection. The vertical axis represents blood pressure, the horizontal axis represents the intensity of Korotkoff sounds, and the display method for displaying the Korotkoff sounds measured symmetrically on the first and second cuffs with the central axis or pressure scale in between is shown schematically. It is a figure. It is a comparative figure of the Korotkoff sound area at the time of simultaneous measurement of the same pressure blood pressure of both arms at rest. It is a comparative figure of the Korotkoff sound at the time of simultaneous measurement of the same pressure blood pressure of both arms after ischemia of only one side for a certain period of time. It is a block diagram which shows schematic structure of the conventional blood pressure measuring apparatus.

FIG. 1 is a block diagram schematically showing the configuration of the blood pressure measuring device according to the embodiment of the present invention, and FIG. 2 is a schematic view showing an enlarged main part of the blood pressure measuring device of FIG.

As shown in FIG. 1, the blood pressure measuring device according to the embodiment of the present invention has a first main rubber sac 1A and a second main rubber sac 1A and a second main rubber sac as a plurality of arterial compression sac that are attached to a plurality of measurement sites and compress the arteries. A rubber sac 1B and a first secondary rubber sac 2A and a second secondary rubber sac 2B as a plurality of Korotkoff sound measurement sac for measuring the Korotkoff sound, which is an arterial sound generated when an artery is compressed, are provided. As shown in FIG. 2, the first main rubber sac 1A and the first sub-rubber sac 2A and the second main rubber sac 1B and the second sub-rubber sac 2B are connected via sufficiently thin conduits 1C and 1D, respectively. Has been done. The first main rubber sac 1A and the second main rubber sac 1B are composed of a thin rectangular parallelepiped.

In the following, for convenience of explanation, when the cross-sectional area of the first main rubber sac 1A, the second main rubber sac 1B, the first secondary rubber sac 2A, or the second secondary rubber sac 2B is described, the conduit 1C, It shall indicate the opening area of the cross section (diametrically) perpendicular to the longitudinal direction of 1D. Similarly, when the cross-sectional area of the conduits 1C and 1D is described, it indicates the opening area of the cross section perpendicular to the longitudinal direction (diameter direction) unless otherwise specified.

The cross-sectional areas of the first main rubber sac 1A and the second main rubber sac 1B are set to the same area as the cross-sectional areas of the first sub-rubber sac 2A and the second sub-rubber sac 2B. Further, in the cross-sectional area of the conduits 1C and 1D, the Korotkoff sounds based on the same contraction of the heart measured by the first secondary rubber sac 2A and the second secondary rubber sac 2B are the first main rubber sac 1A and the second main rubber sac 1B. It is set to 1/10 of the cross-sectional area of the 1st main rubber sac 1A and the 2nd main rubber sac 1B (attenuation rate 1/10) so as to be attenuated to a predetermined level or less when propagating to. The first main rubber sac 1A and the first secondary rubber sac 2A form the first cuff, and the second main rubber sac 1B and the second secondary rubber sac 2B form the second cuff.

A plurality of microphones 3A and 3B for measuring Korotkoff sounds are connected to the first sub-rubber sac 2A and the second sub-rubber sac 2B, respectively. These microphones 3A and 3B are connected to the CPU 7 as a control means described later via signal amplifier circuits 4A and 4B, respectively.

Further, a pressurizing device 5, an exhaust control device 6, and a pressure detecting circuit 10 are connected to the first main rubber sac 1A and the second main rubber sac 1B via pressure supply pipes 1E and 1F, respectively. The pressurizing device 5, the exhaust control device 6, and the pressure detecting circuit 10 are all connected to the CPU 7, and the pressure in the first main rubber sac 1A and the second main rubber sac 1B is detected by the pressure detecting circuit 10 and the CPU 7 By driving and controlling the pressurizing device 5 and the exhaust control device 6, the pressure in the first main rubber sac 1A and the second main rubber sac 1B can be arbitrarily set.

Further, electromagnetic air valves 11A and 11B controlled by the CPU 7 are connected in the middle of the pressure supply pipes 1E and 1F, respectively. By opening and closing the electromagnetic air valves 11A and 11B, respectively, the CPU 7 can pressurize and depressurize the first main rubber sac 1A and the second main rubber sac 1B at the same time or only a specific one. That is, the CPU 7 can select simultaneous measurement or independent measurement at a plurality of locations by switching the opening and closing of these electromagnetic air valves 11A and 11B. When the electromagnetic air valves 11A and 11B are open, all the air systems formed by the shaded areas in FIG. 1 are configured to be held at the same pressure.

Further, a display device 8 and a recording device 9 are connected to the CPU 7. In the display device 8, the Korotkoff sounds measured in the first sub-rubber sac 2A and the second sub-rubber sac 2B can be displayed by the display method described later. Further, the recording device 9 can record the measured Korotkoff sounds.

In the blood pressure measuring device of the present embodiment, the arteries are formed by the first main rubber sac 1A and the second main rubber sac 1B, instead of directly applying the microphone to the arteries of the arm or leg in order to measure the Korotkoff sounds. Korotkoff sounds that are air-conducted in the first secondary rubber sac 2A and the second secondary rubber sac 2B by wrapping the first secondary rubber sac 2A and the second secondary rubber sac 2B on the arteries of the arm or leg to be measured. Are measured at the same pressure at the same time.

That is, the first cuff and the second cuff composed of the first main rubber sac 1A and the first secondary rubber sac 2A and the second main rubber sac 1B and the second secondary rubber sac 2B, respectively, are used as a well-known blood pressure measuring device. When the electromagnetic air valves 11A and 11B are opened and pressurized by the pressurizing device 5, the first main rubber sac 1A and the first main rubber sac 1A and The second main rubber sac 1B swells and blocks the artery. At this time, the first secondary rubber sac 2A and the second secondary rubber sac 2B are also pressurized through the conduits 1C and 1D.

After blocking the artery, the exhaust control device 6 is driven and controlled to gradually exhaust the air in the first main rubber sac 1A and the second main rubber sac 1B to reduce the pressure, and a Korotkoff sound appears in the artery. To do. This Korotkoff sound is detected in the first secondary rubber sac 2A and the second secondary rubber sac 2B. The Korotkoff sounds, which are sound waves measured by the microphones 3A and 3B, are transmitted to the CPU 7 after being amplified and waveform-processed by the signal amplification circuits 4A and 4B. The CPU 7 processes the transmitted Korotkoff sounds and the pressure data detected by the pressure detection circuit 10 when the Korotkoff sounds are generated, displays them on the display device 8, and records the displayed data on the recording device 9.

なお、この（１）式は、第２主ゴム嚢１Ｂ、導管１Ｄおよび第２副ゴム嚢２Ｂについても同様に成立する。 Here, the intensity of the air vibration (Korotkoff sound) generated in the first main rubber sac 1A and the second main rubber sac 1B by the air vibration generated in the first secondary rubber sac 2A and the second secondary rubber sac 2B is It is expressed by the following equation.

The equation (1) also holds for the second main rubber sac 1B, the conduit 1D, and the second auxiliary rubber sac 2B.

As described above, the first main rubber sac 1A and the second main rubber sac 1B are connected to the first secondary rubber sac 2A and the second secondary rubber sac 2B via the conduits 1C and 1D having a cross-sectional area of 1/10. Has been done. Therefore, the Korotkoff sounds detected in the first sub-rubber sac 2A and the second sub-rubber sac 2B are about one tenth when they are propagated to the first main rubber sac 1A and the second main rubber sac 1B. It is attenuated by the signal strength.

Therefore, the Korotkoff sounds due to the same contraction of the heart can be measured in the first secondary rubber sac 2A and the second secondary rubber sac 2B. On the other hand, the first main rubber sac 1A and the second main rubber sac 1B connected via the pressure supply pipe 1E which is a part of the air system are connected to the first secondary rubber sac 2A and the second via the conduits 1C and 1D. 2 The Korotkoff sounds detected in the secondary rubber sac 2B are attenuated to 1/10 and propagated. Therefore, it is possible to suppress the harmful effects of mutual air vibration or Korotkoff sound interference in the first main rubber sac 1A and the second main rubber sac 1B that share the air system to the extent that the measurement is not hindered.

That is, since the Korotkoff sounds at a plurality of sites are simultaneously measured by utilizing the air conduction in the first sub-rubber sac 2A and the second sub-rubber sac 2B, in general, both first sub-rubber sac 2A and the second sub-rubber sac 2A and The Korotkoff sounds measured by the second secondary rubber sac 2B may interfere with each other, making it impossible to accurately measure the respective Korotkoff sounds. However, in the blood pressure measuring device of the present embodiment, Korotkoff sounds are detected using conduits 1C and 1D having a sufficiently small cross-sectional area with respect to the first main rubber sac 1A and the second main rubber sac 1B, which are the arterial compression sac. Since the first secondary rubber sac 2A and the second secondary rubber sac 2B, which are sac, are connected to the first main rubber sac 1A and the second main rubber sac 1B, the first secondary rubber sac 2A and the second secondary rubber sac 2B The Korotkoff sounds measured in 1 are attenuated to 1/10 when propagating to the 1st main rubber sac 1A and the 2nd main rubber sac 1B that share the air system, and the 1st main rubber that shares the air system. In the sac 1A and the second main rubber sac 1B, the harmful effects due to mutual air vibration or interference of Korotkoff sounds can be suppressed to the extent that the measurement is not hindered.

Further, in this device, electromagnetic air valves 11A and 11B are incorporated in the pressure supply pipes 1E and 1F, and by controlling these with the CPU 7, simultaneous measurement of the left and right arms or measurement of the left and right arms alone is possible, and further. It is possible to control the exhaust after simultaneous pressurization of the left and right arms so that only the left and right arms or the left and right arms are exhausted at the same time.

Next, a display method on the display device 8 will be described. FIG. 3 is a characteristic diagram showing the compression pressure by the cuff during blood pressure measurement (hereinafter, also referred to as “arterial compression pressure”) and the Korotkoff sound, and shows the relationship between the Korotkoff sound generated during blood pressure measurement and the compression pressure by the cuff. ing. FIG. 4 is a characteristic diagram showing Korotkoff sounds showing the relationship between the compression pressure by the cuff and the Korotkoff sounds after half-wave detection. The Korotkoff sounds shown in FIG. 3 are detected in half-waves, and each amplitude is expressed by the length of a straight line. It is a characteristic diagram.

As shown in FIG. 5, the display device 8 has the blood pressure on the vertical axis and the intensity of the Korotkoff sounds on the horizontal axis, and the Korotkoff sounds measured by the first cuff and the second cuff with the central axis or the pressure scale in between, respectively. Is displayed symmetrically. In this way, the Korotkoff sounds measured at multiple sites at the same time can be easily compared. That is, in this apparatus, a part of the data obtained by the display method of FIG. 4 is extracted and displayed as shown in FIG.

The relationship between arterial compression and Korotkoff sounds during blood pressure measurement is as shown in FIG. That is, when the first cuff or the second cuff is pressurized by the pressurizing device 5 with a pressure sufficient to block the arteries, the exhaust control device 6 is driven and controlled to gradually reduce the compression pressure. Blood flow in the artery resumes when systolic blood pressure and arterial compression are approximately equal. When blood flow resumes while the artery is compressed, turbulence occurs in the artery and Korotkoff sounds are generated. This Korotkoff sound is enhanced as the blood flow increases as the decompression progresses, but when the pressure is further reduced and the arterial compression pressure becomes a pressure that does not impair the blood flow, the Korotkoff sound disappears.

Therefore, in the blood pressure measuring device of the present embodiment, the Korotkoff sounds obtained as shown in FIG. 3 are detected by half waves, and each amplitude is expressed by the length of a straight line as shown in FIG. 4, and the half waves shown in FIG. 4 are expressed. The detected Korotkoff sounds are extracted, the vertical axis is the arterial compression pressure, the horizontal axis is the intensity of the Korotkoff sounds, and the Korotkoff sounds measured at different sites at the same time with the first and second cuffs are shown in FIG. It can be displayed symmetrically with the central axis or the pressure scale drawn in the center in between. As a result, Korotkoff sounds based on the same contraction of the heart measured at a plurality of sites can be easily compared.

Further, the area surrounded by the line connecting the peaks of the Korotkoff sounds in each heartbeat at this time is proportional to the blood flow rate at the measurement site.

As described above, according to the blood pressure measuring device of the present embodiment, the first main rubber sac 1A and the second main rubber sac 1B, which are rubber sac for blocking arteries, and the rubber sac for measuring Korotkoff sounds. The first sub-rubber sac 2A and the second sub-rubber sac 2B are separate bodies, and the first main rubber sac 1A and the second main rubber sac are measured by the first sub-rubber sac 2A and the second sub-rubber sac 2B. Since the cross-sectional areas of the conduits 1C and 1D are set small enough to sufficiently attenuate the Korotkoff sounds transmitted to the rubber sac 1B, the interference of the Korotkoff sounds generated in the first main rubber sac 1A and the second main rubber sac 1B is minimized. It can be suppressed to the limit. As a result, when the Korotkoff sounds detected in the first sub-rubber sac 2A and the second sub-rubber sac 2B are measured with the microphones 3A and 3B, the influence of the interference of the Korotkoff sounds can be ignored, which is caused by the same contraction of the heart. Korotkoff sounds can be measured simultaneously at multiple sites with high accuracy. Further, in this blood pressure measuring device, by controlling the electromagnetic air valves 11A and 11B by the CPU 7, not only the measurement parts at a plurality of places are measured at the same pressure at the same time, but also only the specific measurement parts are pressurized and exhausted. It is also possible to pressurize and depressurize.

Further, since the blood pressure measuring device in the present embodiment can simultaneously measure Korotkoff sounds at a plurality of sites under the same conditions, it is possible to compare the blood pressure and blood flow between the sites, which is useful for diagnosing arteriosclerosis and the like. .. In addition, since the Korotkoff sounds measured simultaneously at a plurality of parts can be displayed symmetrically on the same display screen, comparative studies can be easily performed. Further, since the air system can be shared between the first cuff and the second cuff, the manufacturing cost of the apparatus can be reduced and the measurement process can be simplified.

In the above description, the case where the cross-sectional areas of the conduits 1C and 1D are 1/10 or less of the volumes of the first main rubber sac 1A and the second main rubber sac 1B has been described, but the ratio of these cross-sectional areas has been described. Is not limited to the values used in the above description, and the cross-sectional areas of the conduits 1C and 1D are based on the volumes of the first main rubber sac 1A and the second main rubber sac 1B so that the Korotkoff sounds can be sufficiently measured. Should be small enough.

Further, in the above description, the cross-sectional areas of the first main rubber sac 1A and the second main rubber sac 1B and the cross-sectional areas of the first sub-rubber sac 2A and the second sub-rubber sac 2B have the same area. Although the case where they are set has been described, these cross-sectional areas may be different, and the Korotkoff sounds detected in the first sub-rubber sac 2A and the second sub-rubber sac 2B are attenuated by a desired attenuation ratio. It suffices if it is configured so that it can detect.

Further, in the above description, the Korotkoff sounds measured in the first secondary rubber sac 2A and the second secondary rubber sac 2B are attenuated as they propagate to the first main rubber sac 1A and the second main rubber sac 1B. Although this has been explained, Korotkoff sounds and some interference waves may occur on the side of the first main rubber sac 1A and the second main rubber sac 1B, which are the arterial compression sac. However, the cross-sectional areas of the first sub-rubber sac 2A and the second sub-rubber sac 2B are set to be the same as the cross-sectional areas of the first main rubber sac 1A and the second main rubber sac 1B, and the cross-sectional areas of the conduits 1C and 1D. Is one tenth of the volume of the first main rubber sac 1A and the second main rubber sac 1B, so that the Korotkov sound and some interference waves are generated on the first main rubber sac 1A and the second main rubber sac 1B side. Propagation to the secondary rubber sac 2A and the second secondary rubber sac 2B does not affect the measurement of the Korotkov sound with the microphones 3A and 3B connected to the first secondary rubber sac 2A and the second secondary rubber sac 2B.

It is possible to evaluate the vascular endothelial function using the blood pressure measuring device in the present embodiment. When evaluating vascular endothelial function, blood pressure is measured simultaneously on the left and right at rest, and the left and right Korotkoff sound pressures at that time are recorded at the same time. Since there may be a difference in the left and right Korotkov sound pressures depending on the subject, the Korotkov sound pressure ratio S1 at the time of simultaneous left and right simultaneous pressure measurement at rest is stored.

After the simultaneous left and right measurement at rest, the blood vessel on the side where the vascular endothelial function is to be examined is ischemic with a compression pressure sufficiently higher than the intravascular pressure for a certain period of time, the compression pressure is released at once, and the blood pressure is measured almost immediately after that. , The vascular endothelial function is evaluated by comparing the left and right Korotkoff sounds at that time.

Korotkoff sounds are said to be caused by a vortex caused by a collision between blood pumped from the heart and blood in a congested state with veins blocked by pressure. The formula of the kinetic energy is expressed as follows.

である。 The mechanical energy before an object A having a velocity v and a mass m ₁ collides with an object B having a _{velocity v and a mass m 2 is}

Is.

となる。 When the above equation (2) is expanded by the law of conservation of momentum, the collision energy is

Will be.

That is, if the left and right blood flow velocity v ² is the same and the blood storage capacity (congestion volume at the time of ischemia) m _{2 of} the left and right arms is the same, the Korotkoff sound generated by the vortex generated by the collision energy is the blood vessel diameter. It depends on the blood flow rate m _{1 by.}

In general, the blood flow velocity of the same subject is the same on the left and right unless there is a special disease, and the peripheral blood storage capacity m ₂ of the ischemic blockage may be considered to be the same. Therefore, the sound pressure of the Korotkoff sounds when the blood pressure is measured at the same time on the left and right depends on the blood vessel diameter.

Next, a specific procedure for evaluating vascular endothelial function using the blood pressure measuring device in the present embodiment will be described.

Temporarily, attach the first cuff to the upper right arm, attach the second cuff to the upper left arm, open both the electromagnetic air valves 11A and 11B, first measure the blood pressure at the same pressure on the left and right, and Korotkoff generated during the measurement. Record the sound (see Figure 5). This is because there is a difference in the left and right Korotkoff sound pressures even at rest depending on the subject. At this time, as shown in FIG. 6, the left-right ratio of the area surrounded by the line connecting the peaks of the Korotkoff sounds generated for each of the left and right heartbeats (area ratio S1 = area of the right Korotkoff sound a1 / left Korotkoff sound). Calculate the area a2). This area ratio S1 is the ratio S1 of the left and right Korotkoff sound pressures, and correlates with the ratio of the blood flow of the left and right arms.

Next, when evaluating the vascular endothelial function of the upper right arm, the electromagnetic air valve 11B installed in the middle of the pressure supply pipe 1F to the second cuff attached to the left arm is closed to supply the pressure to the second cuff. Cut off. Since the electromagnetic air valve 11A is opened to the first cuff attached to the upper right arm, pressure is supplied from the pressure supply pipe 1E. Then, after pressing for a certain period of time with a pressure sufficiently higher than the systolic blood pressure in the right arm measured first, the exhaust control device 6 is opened and the pressure is rapidly released. When the pressure of the first cuff is completely released, the electromagnetic air valve 11B is opened, the exhaust control device 6 is closed, and the blood pressure is measured again at the same pressure on the left and right arms. As shown in FIG. 7, the left and right Korotkoff sounds generated during blood pressure measurement are the area ratio S2 (= the area of the right Korotkoff sound b1 / the area of the left Korotkoff sound) in the line connecting the peaks of the Korotkoff sounds for each of the left and right heartbeats. b2) is calculated.

The endothelial function of a blood vessel is a function of dilating a blood vessel by releasing nitric oxide from the vascular endothelial cells due to the shear stress generated by the blood flow generated at that time when the ischemia is released immediately after the ischemia. In the simultaneous left and right simultaneous pressure blood pressure measurement, the vascular endothelial function can be evaluated by comparing the Korotkoff sound pressure of the right arm after ischemia for a certain period of time with the Korotkoff sound pressure of the left arm without ischemia.

However, since some subjects originally had a difference in the loudness of the left and right Korotkoff sounds, only the right arm shown in FIG. 7 was pressed with the left and right Korotkoff sound area ratio S1 at the time of the resting measurement shown in FIG. It is necessary to correct the left and right Korotkoff sound area ratio S2 at the time as shown in the following equation (4).

The purpose of measuring with the same pressure on the left and right is to eliminate the effect of vascular contraction on the autonomic nerve reflex. That is, the artery is controlled by the autonomic nerve, and the blood vessel diameter may change instantly due to the influence, but since this effect acts simultaneously on the left and right, when the left and right are measured at the same pressure, the autonomic nerve The impact can be eliminated. In addition, the contraction of the heart is not always constant, and the intensity of the contraction may vary from contract to contraction. Therefore, accurate results cannot be obtained unless the left and right Korotkov sound pressures in the same contraction are compared.

Evaluation of vascular endothelial function is a test to evaluate the degree of dilation when carbon monoxide is released from vascular endothelial cells due to shear stress when the ischemia is opened instantly, and the blood vessels dilate, and is usually performed by ultrasonic waves. A blood vessel whose diameter is expanded by 6% or more is considered normal. As described above, the ratio of the left and right Korotkoff sound pressures (area ratio of Korotkoff sounds) S1 shown in FIGS. 5 and 6 is proportional to the blood flow, that is, it can be said that it reflects the blood vessel diameter. In the blood pressure measuring device of the present embodiment, the vascular endothelial function is evaluated not by the change of the blood vessel diameter but by the change of the blood flow volume.

For example, an increase in blood vessel diameter by 6% means an increase in cross-sectional area by 12%. Therefore, if the area ratio S1 of Korotkoff sounds after ischemia to the resting cross-sectional area is 112% or more, the vascular endothelium Can be evaluated as normal. That is, in the blood pressure measuring device of the present embodiment, the expansion of the blood vessel diameter can be estimated from the Korotkoff sound at the time of blood pressure measurement, and the vascular endothelial function can be evaluated.

As described above, by using the blood pressure measuring device in the present embodiment, the vascular endothelial function can be evaluated non-invasively and easily.

The blood pressure measuring device of the present invention is useful as a blood pressure measuring device for measuring blood pressure by measuring the Korotkoff sounds generated when the arteries are blocked, and in particular, measures the Korotkoff sounds based on the same contraction of the heart measured at a plurality of sites. It is suitable as a blood pressure measuring device capable of measuring Korotkoff sounds and measuring blood pressure even in only a part of the blood pressure.

1A 1st main rubber sac 1B 2nd main rubber sac 1C, 1D conduit 1E, 1F Pressure supply pipe 2A 1st secondary rubber sac 2B 2nd secondary rubber sac 3A, 3B Microphone 4A, 4B Signal amplifier circuit 5 Pressurizer 6 Exhaust Control device 7 CPU
8 Display device 9 Recording device 10 Pressure detection circuit 11A, 11B Electromagnetic air valve

Claims (3)

Multiple arterial compression sacs that are attached to the left and right measurement sites of the upper or lower limbs to compress the arteries,
A plurality of Korotkoff sound measurement sac for measuring Korotkoff sounds generated when an artery is compressed, and a plurality of Korotkoff sound measurement sac connected to the plurality of arterial compression sac one by one via a conduit.
A plurality of microphones connected to the plurality of Korotkoff sound measurement sac, respectively, and
A plurality of pressure supply tubes connected to the plurality of arterial compression sac, respectively,
A plurality of electromagnetic air valves provided in the middle of the plurality of pressure supply pipes, and
It is a control means that can pressurize and depressurize the plurality of arterial compression sac at the same time or only a specific arterial compression sac by opening and closing each of the plurality of electromagnetic air valves, and the plurality of electromagnetic air valves are opened. Control to measure the blood pressure of both the left and right measurement sites of the upper limb or the lower limb at the same pressure, and then open only the specific electromagnetic air valve on either the left or right of the upper limb or the lower limb to measure the blood pressure of the specific measurement site. A blood pressure measuring device having means. The conduit opens so that the Korotkoff sounds based on the same contraction of the heart measured at multiple sites by the plurality of Korotkoff sound measuring sac are attenuated below a predetermined level as they propagate to the plurality of arterial compression sac. The blood pressure measuring device according to claim 1, wherein the area is set. The opening area of the conduit is set so that the attenuation rate of the Korotkoff sounds propagating from the plurality of Korotkoff sound measuring sac to the plurality of arterial compression sac is 1/10 or less. The described blood pressure measuring device.

Images