JP4764674B2 - Blood pressure pulse wave inspection device - Google Patents

Description

The present invention relates to a blood pressure pulse wave inspection apparatus, and more particularly, to a blood pressure pulse wave inspection apparatus that measures blood vessel compliance and pulse wave propagation velocity, which are indicators of arteriosclerosis of a living circulatory artery.

Conventionally, vascular compliance has been used as an index of arteriosclerosis. The blood vessel compliance K is defined as a parameter representing the extensibility of the blood vessel when the intravascular volume that increases per unit length of the blood vessel when the intravascular pressure increases by ΔP is defined as a volume pulse wave ΔV, and K = ΔV / ΔP [cm ³ / (dyne / cm ² )] = 2πR ³ (1-σ ² ) / E · h (R: vessel diameter, σ: Poisson's ratio, h: vessel diameter thickness, E: elastic modulus) expressed.

  The blood vessel compliance K can be obtained by measuring the arterial pressure and measuring the blood vessel wall displacement based on the blood vessel diameter and pulsation using an ultrasonic method (see, for example, Patent Document 1 and Patent Document 2). In these cases, in addition to attaching a cuff for blood pressure measurement to the upper arm or lower limb, measurement cannot be performed unless a device such as a sensor is attached to the finger or the like, and measurement can only be performed by a specialized medical institution. It was a thing.

  The blood vessel elasticity measuring apparatus described in Patent Document 3 solves the above-described problems and makes it possible to easily measure an index of arteriosclerosis without requiring a separate apparatus.

  However, such a vascular elasticity measuring device has technical problems described below.

Japanese Patent No. 3184349 JP-A-8-66377 JP 2004-313605 A

  As an index of arteriosclerosis, it is common to use the pulse wave velocity in addition to the blood vessel compliance described above, and these two types of measurement results may be used in combination.

  However, the blood vessel elasticity measuring device described in Patent Document 3 can only measure blood vessel compliance, and if it is intended to measure the pulse wave propagation velocity, an additional device for measuring the pulse wave propagation velocity is required. It was annoying for the patient.

  Moreover, conventionally, blood vessel compliance and pulse wave propagation velocity have pressure dependency (the values change depending on the blood pressure value and TP value of the subject at the time of measurement (difference between the blood pressure value and the blood pressure value)). However, the measurement method using the conventional measuring apparatus ignores the pressure dependency.

The present invention has been made in view of such conventional problems. The object of the present invention is to measure the pressure of both vascular compliance and pulse wave propagation velocity, which are indicators of arteriosclerosis, in addition to blood pressure measurement. An object of the present invention is to provide a blood pressure pulse wave inspection apparatus capable of measuring characteristics using the same apparatus.

To achieve the above object, the present invention provides a main cuff wound around a subject, and a blood pressure calculation means for measuring the subject's highest blood pressure value SBP and lowest blood pressure value DBP in the course of changing the cuff pressure of the main cuff. In the blood pressure pulse wave inspection apparatus comprising: the two or more sub-cuffs provided on the inner peripheral side of the main cuff for detecting the pulse wave of the subject; and a process of changing the cuff pressure of the main cuff, At each cuff pressure, every predetermined time, or every predetermined pulse wave detection, a blood vessel compliance K serving as an index of arteriosclerosis is calculated based on the amplitude value of the pulse wave detected by either the sub-cuff or the main cuff. In the process of changing the cuff pressure of the main cuff and the K calculating means, detection is performed by any two of the sub-cuffs at every predetermined cuff pressure, every predetermined time, or every predetermined pulse wave detection. Based on the propagation delay time of the pulse waves with a predetermined distance between the Sabukafu that, a blood pressure pulse wave examination apparatus comprising: a PWV calculation unit configured to calculate a pulse wave propagation velocity PWV as an index of arteriosclerosis, the said The blood pressure pulse wave inspection device includes a constant-capacity pulse wave generating unit that applies a pressure fluctuation of a predetermined known volume to the main cuff or sub-cuff at every predetermined cuff pressure, every predetermined time, or every predetermined pulse wave detection. And the K calculating means calculates the sensitivity S of the cuff based on the pressure fluctuation amount of the pulse wave detected when the constant volume pulse wave generating unit is driven and the known capacitance value, The volume pulse wave ΔV is calculated based on the amplitude value ΔP of the pulse wave .

  In addition, the blood pressure pulse wave inspection device applies a constant volume pulse wave to the main cuff or the sub cuff, which applies a pressure fluctuation of a predetermined known volume at every predetermined cuff pressure, every predetermined time, or every predetermined pulse wave detection. The K calculating means calculates the sensitivity S of the cuff based on the pressure fluctuation amount of the pulse wave detected when the constant volume pulse wave generating unit is driven and the known capacity value; The volume pulse wave ΔV may be calculated based on the sensitivity S and the amplitude value ΔP of the pulse wave.

  According to this configuration, depending on the pressure fluctuation amount of the pulse wave detected when supplying air from the constant volume pulse wave generating unit and the known capacity value, every predetermined cuff pressure, every predetermined time, or every predetermined pulse wave detection Since the sensitivity of the cuff is calculated, a highly accurate volume pulse wave ΔV can be obtained.

  The constant-capacity pulse wave generation unit may be controlled to be driven a predetermined time after the peak of the pulse wave is detected.

  From the cuff, the pulse wave generated with the supply of the constant-capacity pulse wave generation unit appears superimposed on the pulse wave that is normally detected. Driving the capacitive pulse wave generating unit makes it easier to separate the amplitude of the pulse wave for calculating the cuff sensitivity from the normal pulse wave, and the measurement accuracy is improved.

  The constant-capacity pulse wave generating unit includes an air supply port for supplying air to the cuff, a diaphragm forming a first closed space communicating with the air supply port, and vibrating the diaphragm to form the first You may provide the movable flange part which supplies the air of the predetermined known capacity | capacitance in one closed space, and the coil which moves the said movable flange part up and down by electricity supply.

  This configuration is also adopted as an exhaust structure of a sphygmomanometer, so that parts can be shared and manufacturing processes can be shared.

  In addition, the air supply port is connected to the sub-cuff and includes a back pressure intake port connected to the main cuff, and a second closed space communicating with the back pressure intake port is formed by the diaphragm. The first closed space may be controlled to be maintained at the same pressure as that of the second closed space until the constant-capacity pulse wave generating unit is driven.

  According to this configuration, by keeping the back pressure and the supply air pressure of the constant-capacity pulse wave generating unit at the same level, the pressure balance between the first closed space and the second closed space formed with the diaphragm interposed therebetween can be achieved. In order to supply the necessary amount of air to the cuff from the air supply port, a minimum current can be applied to the coil in a short time.

  The K calculating means calculates the blood vessel compliance K for each predetermined TP value (intravascular pressure-external blood pressure) and integrates the TP value to express the relationship between the vascular cross-sectional area and the TP value. A tube law curve may be obtained.

  According to this, the blood vessel cross-sectional area of the subject can be obtained from the blood vessel compliance by a non-invasive measurement method regardless of the anatomical / invasive technique.

  The PWV calculation means calculates the pulse wave propagation velocity PWV for each predetermined TP value (intravascular pressure-external blood pressure) to obtain a pressure dependence curve, and the tube law curve and the pulse wave The correlation between the blood vessel compliance K and the pulse wave propagation velocity PWV may be obtained by comparing the pressure dependence curve of the wave propagation velocity PWV.

  The PWV calculating means and the K calculating means calculate a pulse wave propagation velocity PWV and a blood vessel compliance K for each predetermined TP value (intravascular pressure−external blood pressure) to obtain a pressure dependence curve. From the pulse wave velocity PWV obtained simultaneously with the TP value and the blood vessel compliance K, a blood vessel cross-sectional area may be calculated to obtain a tube law curve representing the relationship between the blood vessel cross-sectional area and the TP value. .

  Since the pipe law curve and the pressure dependence curve of the pulse wave velocity are in a proportional relationship, the consistency and validity of the vessel compliance K and the pulse wave velocity PWV that are the basis of the tube law curve are compared by comparing them. Judgment of gender is possible.

  The sub-cuff is fixed to the main cuff via a pressure damper that prevents mutual detection of detected pulse waves, and the pressure damper is a dynamic pressure of the sub-cuff and the main cuff that accompanies pulsation of arterial pressure. The pressure pulsations in the sub-cuff and the main cuff can be isolated from each other, and only the volume fluctuation due to the pressure pulse wave of the arterial pressure under the sub-cuff can be detected. May be.

According to this configuration, mutual interference between the cuffs is prevented, and a correct pulse wave can be detected from the cuffs, thereby improving measurement accuracy.

According to the blood pressure pulse wave inspection device of the present invention, in the process of changing the cuff pressure of the main cuff, the pulse detected from the main cuff or the sub cuff at every predetermined cuff pressure, every predetermined time, or every predetermined pulse wave detection. Since the apparatus includes K calculating means for measuring the blood vessel compliance K based on the waves and PWV calculating means for measuring the pulse wave propagation velocity PWV, the pressure characteristics of the blood vessel compliance and the pulse wave propagation velocity can be obtained with a single device. Can be obtained.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a diagram showing a configuration of a blood pressure pulse wave inspection apparatus according to the present invention.

  The blood pressure pulse wave inspection apparatus 1 of the present embodiment is an apparatus that measures a blood vessel compliance K that is an index of arteriosclerosis and a pulse wave propagation velocity PWV in addition to the blood pressure of a subject. First, the blood pressure pulse wave inspection apparatus 1 is wound around the upper arm or lower limb of a control unit 10, a display / switch unit 20, a memory 30, and a temporary arteries that are configured in a general oscillometric sphygmomanometer. Main cuff 40 that is electrically blocked and has an airtight large-capacity flexible bag, a pump 41 that applies air to the main cuff 40, a pump drive circuit 42, and an exhaust valve 43 that exhausts the air in the main cuff 40 An exhaust valve drive circuit 44, a main side sensor 45 that detects the pressure (cuff pressure) in the main cuff 40, and a main side pulse wave extraction circuit 46 that extracts the pulse wave of the subject based on the detection value of the main side sensor 45 I have.

  In the present embodiment, the above-described general sphygmomanometer components are unitized in the form of a sphygmomanometer in appearance.

  The sensors used in this embodiment are all pressure sensors that detect volume fluctuations in the cuff, regardless of whether they are on the main side, upstream side, and downstream side, which will be described later. It doesn't matter.

  All or any of the main side pulse wave extraction circuit 46, the downstream side pulse wave extraction circuit 62, and the upstream side pulse wave extraction circuit 82, which will be described later, may be incorporated in the control unit 10.

  With the above configuration, the control unit 10 supplies air into the main cuff 40 via the pump drive circuit 42 and the pump 41 so that the cuff pressure becomes higher than the intravascular blood pressure in the body of the subject at the start of blood pressure measurement. When the main cuff 40 compresses the measurement site and blocks the blood flow in the body, the control unit 10 stops the supply of air and exhausts the air in the main cuff 40 through the exhaust valve drive circuit 44 and the exhaust valve 43. And gradually reduce the cuff pressure.

  In the process of gradually decreasing the cuff pressure from the state in which the measurement site is compressed by the main cuff 40 and the blood vessel underneath is crushed, blood begins to flow around the maximum blood pressure value, and cuff near the minimum blood pressure value. It is known to start smoothly without being affected by pressure.

  In the process of changing the cuff pressure, the blood pressure calculation means 11 of the control unit 10 generates a pulse wave that is a minute air fluctuation exerted on the inside of the main cuff 40 by the vibration of the blood vessel wall synchronized with the pulsation of the heart. The main side pulse wave extraction circuit 46 extracts the main blood pressure value from the main side sensor 45, and determines the maximum blood pressure value, the minimum blood pressure value, and the average blood pressure value based on the pulse wave. Since the main side sensor 45 obtains a pressure waveform in which the pressure of the pulse wave is superimposed on the cuff pressure pressurized by the pump 41, in order to extract the pulse wave component, from this pressure waveform, Subtract cuff pressure.

  The determination method is that the cuff pressure at the point where the amplitude of the pulse wave (maximum value-minimum value of the pressure for each pulse wave—also referred to as pulse pressure) increases rapidly is the maximum blood pressure value SBP, and the amplitude of the pulse wave decreases rapidly. In general, the cuff pressure at the point to be used is the minimum blood pressure value DBP, and the cuff pressure at the point at which the amplitude of the pulse wave is the maximum is the average blood pressure value MBP. It does not matter.

  These blood pressure values as determination results are stored in the memory 30 and displayed on the display screen of the display / switch unit 20. This is the operating principle of a general oscillometric sphygmomanometer.

  The blood pressure pulse wave examination apparatus 1 according to the present embodiment, in addition to the above-described general sphygmomanometer constituent means, is provided in the control unit 10 and also includes a K calculation unit 12 that calculates a vascular compliance K. PWV calculation means 13 provided inside for calculating the pulse wave propagation velocity PWV, and attached to the inner peripheral side of the main cuff 40 wound around the subject so as to be in contact with the upper arm or lower limb of the subject, and the K calculation means 12 and the PWV A downstream sub-cuff 50 and an upstream sub-cuff 70 for detecting a pulse wave for the calculation means 13, a downstream pulse wave detector 60, and an upstream pulse wave detector 80 are provided.

  2 and 3 are a cross-sectional view, a plan view, and a side view of the downstream side cuff 50 and the upstream side subcuff 70 attached to the main cuff 40, respectively.

  2 and 3, the outer peripheral surface of the main cuff 40 is covered with an outer cover 40a for preventing deformation, and the downstream sub-cuff 50 and the upstream sub-cuff 70 can have a smaller capacity than the main cuff 40. A pressure damper made of synthetic resin or the like at a predetermined distance from the downstream end and the upstream end in the blood flow direction under the main cuff 40 so that the flexible bag contacts the outer peripheral surface of the upper arm or lower limb of the subject. It is fixed to the main cuff 40 via 40b.

  Since the outer cover 40 a serves as a fixed end of the main cuff 40, the bulge when the main cuff 40 is pressed acts only on the inside, and plays a role of not performing work on the external environment of the main cuff 40.

  The downstream sub-cuff 50 is disposed closer to the peripheral nerve such as a finger with respect to the blood flow direction, and the upstream sub-cuff 70 is disposed closer to the blood source (heart), and the distance between the two cuffs is In this embodiment, it is 90 mm (from the center to the center of the cuff).

  In the present embodiment, the upstream sub-cuff 50 and the downstream sub-cuff 70 are manufactured to have the same capacity and the same shape, and have a width of 30 mm in the blood flow direction. However, they need not necessarily have the same capacity and shape. Absent.

  2 and 3, reference numerals 40c, 50c, and 70c denote air supply / exhaust ports to the cuffs 40, 50, and 70, respectively.

  As will be described later, the downstream side cuff 50 and the upstream side subcuff 70 are also connected to the downstream side sensor 61 and the upstream side sensor 81, similarly to the main cuff 40, by the downstream side pulse wave extraction circuit 62 and the upstream side pulse wave extraction circuit 82, respectively. A pulse wave is extracted from the detection signal of the sensor. The pressure damper 40b is used to extract a correct pulse wave without the pulse waves detected by the sensors interfering with each other. The pressure damper 40b of this embodiment has a thickness of 0. It is made of 3mm PP film.

  The pressure damper 40b acts as a fixed end of the dynamic pressure of the sub-cuffs 50, 70 and the main cuff 40 accompanying the pulsation of the arterial pressure, and can isolate the pulsations of pressure in the sub-cuffs 50, 70 and the main cuff 40 from each other. Only volume fluctuations due to the pressure pulse wave of the arterial pressure below 50 and 70 can be detected.

  When the cuff pressure of the main cuff 40 is maintained at 30, 50, 100, 200, and 300 mmHg with the pressure damper 40b of this embodiment interposed between the main cuff 40 and the downstream side sub cuff 50, only the main cuff 40 is provided. FIG. 4 shows the attenuation characteristics when the frequency of a signal having a predetermined amplitude is changed from 1 Hz to 40 Hz and the signal is detected by the downstream sensor 61 of the downstream sub-cuff 50. As can be seen from FIG. 4, the signal detected by the downstream sensor 61 is attenuated to an amplitude of 1/1000 or less of the signal actually given to the main cuff 40 and can be said to be a noise level.

  Therefore, it can be said that the influence of mutual interference between the cuffs is almost eliminated by the pressure damper 40b, and a correct pulse wave can be detected from the cuffs, so that the measurement accuracy is improved.

  Next, the downstream side pulse wave detection unit 60 connected to the downstream side sub cuff 50 in this embodiment uses the K calculation unit 12 of the control unit 10 to determine the blood vessel compliance K, and the PWV calculation unit 13 of the control unit 10. 1 is a means for detecting the downstream pulse wave necessary for calculating the pulse wave propagation velocity PWV from the downstream sub-cuff 50. As shown in FIG. In addition to the wave extraction circuit 62, a constant-capacity pulse wave generation unit 63, a pulse wave generation drive circuit 64, downstream electromagnetic valves 65 a and 65 b, and an air resistance 66 are provided.

  In the present embodiment, the upstream side pulse wave detection unit 80 connected to the upstream side sub-cuff 70 converts the upstream side pulse wave necessary for calculating the pulse wave propagation velocity PWV by the PWV calculation unit 13 of the control unit 10 into the upstream side. This is a means for detecting from the side sub-cuff 70 and, as shown in FIG. 1, includes an electromagnetic valve 83 in addition to the upstream sensor 81 and the upstream pulse wave extraction circuit 82 described above.

  In this embodiment, the downstream pulse wave detection unit 60 and the upstream pulse wave detection unit 80 are combined into a unit as an upstream / downstream pulse wave detection unit (constant volume pulse wave generation / detection device). The sphygmomanometer (the constituent means of the blood pressure pulse wave inspection apparatus 1 having the shape) and the cuffs 40, 50, and 70 are connected via the upstream / downstream pulse wave detector.

  Therefore, the blood pressure pulse wave inspection apparatus 1 can be used as a sphygmomanometer. In that case, the downstream pulse wave detection unit 60 and the upstream pulse wave detection part 80 are simply removed from the blood pressure pulse wave inspection apparatus 1. Good. In other words, the blood pressure pulse wave inspection apparatus of the present invention changes the contents of the control unit of the conventional blood pressure monitor, and connects the blood pressure monitor to the cuff via the downstream pulse wave detection unit 60 and the upstream pulse wave detection unit 80. Therefore, it is not necessary to change the hardware configuration of the conventional sphygmomanometer, and it is possible to share the hardware with a sphygmomanometer dedicated to blood pressure measurement.

  The constant-capacity pulse wave generation unit 63 changes the cuff pressure of the main cuff 40 based on a control instruction from the pulse wave generation drive circuit 64, and detects a predetermined pulse wave every predetermined cuff pressure or every predetermined time. Each means is a means for applying a pressure fluctuation corresponding to a known volume in the downstream side sub-cuff 50, which is a so-called constant capacity pump or piston.

  A sectional view of the constant-capacity pulse wave generating unit 63 of this embodiment is shown in FIG. The constant-capacity pulse wave generating unit 63 of FIG. 5 includes an air supply port 63a connected to the downstream sub-cuff 50 and supplying air, and a back pressure intake port 63b connected to the main cuff 40, the pump 41, and the exhaust valve 43. Yes.

  The air supply port 63a and the back pressure intake port 63b are provided in the cover 63k. The cover 63k is fixed to the opening end of the body 63l formed in a cup shape with a seal material 63m interposed therebetween, and an airtight space is provided by the cover 63k and the body 63l.

  This airtight space is formed by a flexible diaphragm 63e whose outer peripheral edge abuts against the inner surface of the cover 63k, and a second closed space communicated with the first air supply port 63a and a back pressure intake port 63b. It is partitioned into a space 63d.

  The diaphragm 63e is formed in a parabolic antenna shape, and the center portion thereof is supported by the movable flange portion 63f. A hole piece 63h, a magnet 63i, and a yoke 63j are laminated below the movable flange portion 63f, and when the coil 63g provided on the side surface of the hole piece 63f is energized, the diaphragm 63e bends and vibrates. .

  When the diaphragm 63e is bent and vibrated, a predetermined volume of air in the first closed space 63c is supplied from the air supply port 63a to the downstream sub-cuff 50. Such a configuration of the constant-capacity pulse wave generating unit 63 is also adopted as an exhaust structure of a sphygmomanometer, so that parts can be shared and manufacturing processes can be shared.

  The air supply port 63a and the back pressure intake port 63b are connected to each other via the downstream electromagnetic valve 65a, the air resistor 66, and the downstream electromagnetic valve 65b shown in FIG. 1 is connected to the main cuff 40, the pump 41, the exhaust valve 43, and the upstream sub-cuff 70. Further, the upstream electromagnetic valve 83 shown in FIG. The port 63b is also connected.

  In other words, in this embodiment, the cuffs that can be pressurized by the pump 41 through the air supply / exhaust ports are all of the main cuff 40, the downstream sub-cuff 50, and the upstream sub-cuff 70, and only the downstream sub-cuff 50 has a constant capacity pulse. Pressure is also applied from the wave generating unit 63.

  More specifically, when the electromagnetic valves 65a, 65b, 83 are open and the constant-capacity pulse wave generation unit 63 is stopped, the air supply port 63a and the back pressure intake port 63b are connected to each other. Since the communication state is established and all the cuffs 40, 50, 70 are communicated via the pump 41, the same pressure is maintained.

  When the solenoid valves 65a, 65b, 83 are closed, the air supply port 63a of the constant-capacity pulse wave generation unit 63 and the main cuff 40 and the main cuff 40 and the downstream sub-cuff 50 become independent, respectively. A predetermined known volume of air in the first closed space 63c can be reliably supplied to the downstream sub-cuff 50 from the capacitive pulse wave generating unit 63.

  When the solenoid valve 65a connected in series with the air resistance 66 is open, the air resistance 66 is interposed, so that the static pressure between the main cuff 40 and the downstream side sub-cuff 50 is maintained, but the pulse wave Is kept independent. Therefore, the electromagnetic valve 65a may not be provided. Further, a resistor may be used in place of the electromagnetic valves 65a, 65b, 83. Further, an air resistance may be interposed between the electromagnetic valve 83 and the main cuff 40.

  Here, the necessity of sending a predetermined known volume of air into the downstream side sub-cuff 50 will be described together with the blood vessel compliance K measurement method (details of the K calculation means 12) in the present invention.

  As described above, when the intravascular pressure that increases per unit length of the blood vessel is ΔV (hereinafter referred to as volume pulse wave) when the intravascular pressure increases by ΔP, the blood vessel compliance K is K = ΔV / It is obtained by ΔP. In the blood vessel, in order to circulate blood in the body, pressure is generated by periodically repeating the minimum blood pressure value DBP and the maximum blood pressure value SBP in synchronization with the heartbeat. Is called a beat, and is also a pulse wave extraction unit.

That is, ΔP is a difference between the minimum blood pressure value DBP and the maximum blood pressure value SBP, and is obtained by K = ΔV / (SBP−DBP). Note that ΔP here is different from ΔP and ΔP ₀ representing the pulse wave amplitude appearing later.

  Next, the volume pulse wave ΔV necessary for obtaining the blood vessel compliance K cannot be directly measured when a blood pressure measurement cuff is used. Conventionally, a separate device other than the blood pressure measurement device is used. As described in Patent Document 3 (Japanese Patent Application Laid-Open No. 2004-313605), the amplitude of the pulse wave detected from the main sensor 45 of the sphygmomanometer is sensitive to the sensitivity of the main cuff 40 (with respect to the volume change of the main cuff 40). The ratio of pressure change) was applied to obtain a unit conversion from a pressure value to a volume value.

  However, the characteristic of the cuff sensitivity varies depending not only on the pressurized state (pressurized value) but also on the condition of the subject, the measurement time zone, the individual difference of the cuff, and the like. The wave ΔV and consequently the vascular compliance K could not be determined.

  Therefore, in the present invention, in addition to the main cuff 40, a cuff for detecting a volume pulse wave ΔV capable of supplying a predetermined known volume (in this embodiment, the downstream sub-cuff 50) is provided, so that the cuff pressure of the main cuff 40 is increased. Measure the cuff sensitivity (the amount of fluctuation of the cuff pressure per unit capacity change of the cuff internal volume) at every predetermined cuff pressure, every predetermined time, or every predetermined pulse wave detection. By calculating the volume pulse wave ΔV based on the sensitivity of the cuff, a more accurate pressure characteristic of the blood vessel compliance K can be obtained.

  In the present specification, the pressure in the “pressure characteristics” refers to the blood pressure value of the subject at the time of measurement, the blood pressure value (cuff pressure), and the TP value (difference between the blood pressure value and the blood pressure value).

  In this embodiment, the predetermined known capacity is set to 0.15 cc. However, in order to increase the accuracy of the cuff sensitivity, it is desirable to detect the pressure change in the capacity change as small as possible. ~ 0.15cc is preferred.

  It should be noted that the predetermined known capacity may be any capacity that allows the downstream subcuff 50 to detect a change in the blood vessel wall of a human subject, and the predetermined known capacity also depends on the size of the downstream subcuff 50. The capacity ratio varies. Further, in the process of changing the cuff pressure of the main cuff 40, for example, the capacity value supplied by the constant volume pulse wave generating unit 63 may be changed according to the cuff pressure value.

In addition, it is necessary to open the downstream solenoid valve 65a before sending a predetermined known volume of air by keeping the back pressure and the supply air pressure of the constant volume pulse wave generating unit 63 at the same level. In order to maintain a pressure balance between the first closed space 63c and the second closed space 63d formed with the diaphragm 63e interposed therebetween, and to send a necessary volume of air from the air supply port 63a to the downstream sub-cuff 50, a short pressure is required. This is because a minimum current can be applied to the coil 63g in time.

  Next, a method for measuring the pulse wave velocity PWV (details of the PWV calculation means 13) will be described.

  The PWV calculation means 13 is a process of changing the cuff pressure of the main cuff 40, and the upstream side pulse wave detected by the upstream side sub cuff 70 at every predetermined cuff pressure, every predetermined time or every predetermined pulse wave detection, The downstream pulse wave detected by the downstream sub-cuff 50 is compared between the same beats, and the time (propagation time) required for both pulse waves to propagate from upstream to downstream is calculated from the pulse waveform, This is a means for calculating the pressure characteristic of the pulse wave propagation velocity PWV by dividing the reciprocal of the propagation time by the distance between upstream and downstream. In the present embodiment, the distance between the upstream sub-cuff 70 and the downstream sub-cuff 50 is 90 mm from the center to the center of each cuff.

  Conventionally, in order to obtain the pulse wave propagation velocity PWV, for example, a pulse wave detection sensor is provided on the upper arm and an ankle, and the time for the pulse wave to propagate from the upper arm to the ankle is measured to measure the distance between the upper arm and the ankle. It was. However, in this case, the distance between the upper arm and the ankle has a very large individual difference. Therefore, if the distance is uniformly determined, the error becomes very large. Even if the measurement is performed individually, the distance between the upper arm and the ankle is very long, which also causes an error. In addition, it has been troublesome to attach sensors different from the blood pressure measurement cuff to the upper arm and the ankle, respectively.

  Furthermore, since the conventional pulse wave propagation velocity PWV is measured in a normal state with the subject lying down, the blood pressure at the time of measurement varies depending on the subject. As can be seen from the graph showing the PWV-blood pressure characteristics for each degree of arteriosclerosis shown in FIG. 13, the pulse wave propagation velocity PWV is dependent on pressure (the blood pressure value of the subject at the time of measurement and the TP value (intravascular pressure value and It is known that the numerical value may change depending on the difference in the external blood pressure value), and the pulse wave velocity PWV changes not only by the arteriosclerosis level but also by the blood pressure value. In order to perform this, it was necessary to convert to a PWV value at a predetermined blood pressure value.

  However, in the present invention, the pulse wave is detected from the sensors 61 and 81 connected to the cuffs 50 and 70 provided at a predetermined distance on the upstream side and the downstream side below the main cuff 40, and the propagation time between these pulse waves is detected. Since the pulse wave velocity PWV is obtained based on the known distance, there is no need to attach a device other than the blood pressure measurement cuff to the body of the subject as in the conventional case, and there is no need to actually measure the distance between the sensors.

  In addition, since the distance between the upstream side and the downstream side in the main cuff 40 is short compared to the distance between the upper arm and the ankle, it is expected that the calculation accuracy of the pulse wave propagation velocity PWV is improved.

  Further, since the pulse wave propagation velocity PWV can be obtained in the process of changing the cuff pressure of the main cuff 40, the pressure characteristic of the pulse wave propagation velocity PWV can be obtained immediately. Therefore, a graph representing the relationship between the pulse wave velocity PWV and the pressure value can be used as it is for the evaluation of the degree of arteriosclerosis without converting the pulse wave velocity PWV at a predetermined blood pressure value. Of course, the pulse wave velocity PWV at a specific pressure value can be obtained from this graph.

As described above, according to the blood pressure pulse wave inspection apparatus 1, it is possible to measure the pressure characteristics of both the blood vessel compliance K and the pulse wave propagation velocity PWV with the two cuffs 50 and 70 provided in the main cuff 40. .

  With respect to the embodiment in which the blood pressure, blood vessel compliance K, and pulse wave propagation velocity PWV of the subject are measured using the blood pressure pulse wave inspection apparatus 1 having the above-described configuration, the flowcharts of FIGS. This will be described with reference to the configuration diagram of FIG.

  First, the overall flow of this embodiment will be described with reference to FIG. As a premise, it is necessary to wrap the main cuff 40 to which the downstream sub-cuff 50 and the upstream sub-cuff 70 of the present embodiment are fixed around the upper arm or lower limb of the subject.

  First, the blood pressure pulse wave inspection device 1 detects from the main cuff 40 in the process of gradually depressurizing (exhausting) the cuff pressure from a state in which the main cuff 40 is sufficiently pressurized to sufficiently block the blood flow of the subject. The blood pressure of the subject is measured based on the pulse wave to be measured, and the blood vessel compliance K is measured based on the pulse wave detected from the downstream sub-cuff 50 in the same process (S10).

  In this embodiment, the blood vessel compliance K is measured not only when the TP (Transmural Pressure: intravascular pressure value Pa-external blood pressure value Pe) is positive but also when it is positive. Since blood vessel compliance K is measured in the same process as blood pressure measurement, it is a numerical value measured when TP is negative.

  After a predetermined time has elapsed (S20), the blood pressure pulse wave inspection device 1 measures the blood vessel compliance K measured when the TP is mainly positive and the pulse wave propagation velocity PWV (S30). At this stage, the measurement of blood pressure and the measurement of blood vessel compliance K when TP is negative have already been completed. Therefore, the main cuff 40 may be pressurized until it reaches a state of TP in which the blood vessel compliance K is not measured.

  The predetermined time of S20 means that the arterial flow blocked by the cuff in S10 returns to a normal state (a state in which blood flows smoothly), and measurement of blood vessel compliance K and the like can be started without error in S30. The time, which is several seconds to several tens of seconds.

The blood pressure pulse wave inspection apparatus 1 performs analysis based on the measured blood pressure, blood vessel compliance K, and pulse wave propagation velocity PWV, calculates an arteriosclerosis parameter as a comprehensive judgment, and outputs the result (S40).

  Hereinafter, details of each flow of S10 to S40 will be described. First, the blood pressure and blood vessel compliance K measurement flow in S10 will be described with reference to the flowcharts of FIGS.

  The control unit 10 starts blood pressure measurement based on a command from the switch unit of the display / switch unit 20 or the like (S100).

  In order to control the pressurization to the main cuff 40, the control unit 10 first instructs the exhaust valve drive circuit 44 to close the exhaust valve 43 (S105). Then, the pump drive circuit 42 is instructed to drive the pump, and pressurization to the main cuff 40 is started (S110). The pressurization value here is displayed on the display screen of the display / switch unit 20 (S115).

  The controller 10 instructs the pump drive circuit 42 to drive the pump until the pressurization value reaches the set value (S120), and when the set value is reached, instructs the pump drive circuit 42 to stop the pump (S125). . The set value here refers to a pressure value that is equal to or higher than the maximum blood pressure value, but since the maximum blood pressure value of the subject has not been measured at this time, the pressure has a margin with respect to the general maximum blood pressure value. A value (for example, 180 mmHg) is set.

  When the pressurization by the pump 41 is stopped, the control unit 10 closes the electromagnetic valve 65b (S130). As a result, the air supply port 63a and the back pressure intake port 63b of the constant-capacity pulse wave generation unit 63 are in communication with each other via the electromagnetic valve 65a and the air resistance 66, and a static pressure is generated between the main cuff 40 and the downstream side sub cuff 50. Become the same.

  The control unit 10 instructs the exhaust valve drive circuit 44 to open / close the exhaust valve 43 (S135). Specifically, the exhaust valve 43 is controlled so that the cuff pressure of the main cuff 40 is reduced at a rate of several mmHg (for example, 4 mmHg) per second.

  In the process in which the control unit 10 gradually reduces the cuff pressure in the main cuff 40 in S135, the control unit 10 measures the volume pulse wave ΔV shown in the flowchart of FIG. 8 (S140).

Details of S140 will be described below with reference to the flowchart of FIG. The downstream side pulse wave extraction circuit 62 constantly monitors the cuff pressure detected from the downstream side sensor 61 and stores the entire waveform of the extracted pulse wave in the memory 30. The cuff pressure of the main cuff 40 is reduced until the cuff pressure reaches a predetermined value P _i (i = 1 to n) (S145).

The flow from S145 to S195, which is the details of the volume pulse wave measurement in S140, is a process of reducing the cuff pressure. In S210, which will be described later, it is determined whether or not the cuff pressure has become lower than the K measurement lower limit value. As a result, when it is not less than the K measurement lower limit value, the same flow is repeated again. Therefore, _i of the predetermined value P _i is added and updated sequentially from 1.

In the present embodiment, the predetermined value P _i is determined to be 1 for each pulse wave of the subject. That is, the predetermined value P _i exists for the number of pulse waves. For example, the control unit 10 always differentiates the extracted pulse wave with respect to time, sets the cuff pressure P _i = P1 at the point where the differential value (waveform slope) changes from negative to positive, and stores the cuff pressure in the memory 30. The fact that the differential value changes from negative to positive means that a new pulse wave has been generated, whereby the pulse wave is recognized (S150).

When the pulse wave is recognized, the downstream side pulse wave extraction circuit 62 recognizes the pulse wave peak point P _p at which the amplitude, which is the pressure difference from the previously determined cuff pressure P1, is maximum, and the pulse wave peak. stored in the memory 30 pulse wave amplitude value ΔP a (P1) as an amplitude value for each pulse wave at the point _{P p} (S155).

In order to recognize the pulse wave peak point P _p , a method of continuously performing time differentiation of the pulse wave waveform and searching for a point that becomes 0 in the process in which the differential value changes from positive to negative, cuff pressure P _i Any method may be employed, such as a method of continuously monitoring the pressure change amount and searching for a point where the change amount becomes maximum.

The controller 10 waits for a predetermined time Δt to elapse after recognizing the pulse wave peak point P _p (S160). After Δt has elapsed, the electromagnetic valve 65a is closed (S165). This is because the main cuff 40 and the downstream sub-cuff 50 are completely insulated so that the air supplied from the constant-capacity pulse wave generating unit 63 is reliably supplied to the downstream sub-cuff 50 and does not leak into the main cuff 50. . The value of Δt may be any period until the next pulsation starts, but in this embodiment, Δt = 200 ms. Alternatively, Δt may be set when the pulse wave amplitude value is 50% of the pulse wave amplitude value ΔP (P _i ) at the pulse wave peak point P _p .

Immediately thereafter, the control unit 10 issues a command to the pulse wave generation drive unit, and the volume in the downstream side sub-cuff 50 by the known capacity ΔV ₀ (0.15 cc) is applied to the coil 63g of the constant-capacity pulse wave generation unit 63 for t2 hours. Supply current to increase. The electromotive force generated between the coil 63g and the magnet 63i by this current moves the movable flange portion 63f up and down. As the movable flange portion 63f is moved up and down, the diaphragm 63e vibrates, and air of a known volume ΔV ₀ in the first closed space 63c is supplied to the downstream sub-cuff 50 (S170). In this embodiment, the known capacity ΔV ₀ is set to 0.15 cc. However, it may be different for each pulse wave. In this case, the current value applied to the coil 63g may be controlled.

Thereby, the cuff pressure of the downstream side sub-cuff 50 increases as the capacity increases by the known capacity ΔV ₀ . The downstream side pulse wave extraction circuit 62 detects the pressure fluctuation amount ΔP ₀ (P1) of the pulse wave at this time from the downstream side sensor 61 and stores it in the memory 30 (S175).

The constant-capacity pulse wave generating unit 63 is driven after Δt after the peak of the pulse wave. If the pulse wave is driven at the peak of the pulse wave, the capacity is increased by a known capacity ΔV ₀ minutes. This is because the accompanying pressure fluctuation amount ΔP ₀ (P1) of the pulse wave appears superimposed on the peak waveform, so that it is difficult to accurately measure the fluctuation, and this is surely prevented.

  After the elapse of time t2, the previous solenoid valve 65a is opened (S180). As a result, the static pressures of the main cuff 40 and the downstream side sub cuff 50 are made the same again.

Here, in FIG. 14, the processes of S145 to S180 are repeatedly executed, and the pulse wave waveform detected by the downstream sensor 61 is recorded for a total of three pulse waves when the cuff pressure Pi becomes P1, P2, and P3. FIG. 15 shows an enlarged waveform of one pulse wave (pulse wave when the cuff pressure Pi is P1). 15, the cuff pressure P _i is reached the pulse wave peak point P _p from the point where the P1, substantially rectangular waveforms appearing at that Δt elapsed from the pulse wave peak point P _p is given known volume [Delta] V ₀ Is the pressure fluctuation amount ΔP ₀ (P1) of the pulse wave when the air is supplied. In the present embodiment, a current such that a substantially rectangular pulse wave waveform appears is supplied to the coil 63g, but it is not always necessary to generate a substantially rectangular waveform.

After the pulse wave pressure fluctuation amount ΔP ₀ (P1) is detected from the downstream sensor 61, the K calculating means 12 calculates the pulse wave pressure fluctuation amount ΔP ₀ (P1) and the known capacity ΔV ₀ based on the values. The cuff sensitivity S _e (P1) is calculated (S185). The cuff sensitivity S _e (P _i ) represents the fluctuation amount of the cuff pressure per unit capacity change of the cuff internal volume when the cuff pressure is P _i , and S _e (P _i ) = ΔP ₀ It is obtained by (P _i ) / ΔV ₀ .

FIG. 16 is a graph showing the relationship between the pulse wave pressure fluctuation amount ΔP ₀ (P _i ) and the cuff pressure P _i measured in this example for a plurality of different types of cuffs. In the present embodiment, the value of the known capacity ΔV ₀ is constant regardless of the cuff pressure P _i . That is, the tendency of the graph of FIG. 16 represents the cuff sensitivity S _e (P _i ) as it is. According to FIG. 16, since the sensitivity of the cuff by the type and cuff pressure P _i of the cuff can be seen to vary, thus seeking sensitivity of the cuff individually determine the exact volume pulse ΔV and vascular compliance K Understand the importance of

K calculating means 12, a pulse wave amplitude value ΔP in the pulse wave peak point _{P p} (P1), based on the sensitivity of the cuff _S e (P1), to calculate the volume pulse ΔV (P1) (S190). The volume pulse wave ΔV (P _i ) is a pressure unit, and the pulse wave amplitude value ΔP (P _i ) at the pulse wave peak point P _p is converted into a volume unit based on the cuff sensitivity S _e (P _i ). Therefore, ΔV (P _i ) = ΔP (P _i ) / S _e (P _i ) is obtained.

  The K calculating means 12 stores the obtained volume pulse wave ΔV (P1) in the memory 30 (S195).

On the other hand, the main side pulse wave extraction circuit 46 always extracts the pulse wave on the main cuff 40 side from the time when the exhaust control is started in S135, and stores it in the memory 30 together with the amplitude value for each pulse wave. Then, blood pressure calculation unit 11, the cuff pressure _{P i} is a predetermined pressure determinable value (e.g., diastolic blood pressure 40mmHg for hypotension human) upon reaching (S200), stored in the memory 30 pulse Based on the amplitude value of the wave, the determination of the maximum blood pressure value SBP, the minimum blood pressure value DBP, and the average blood pressure value MBP is performed (S205) and stored in the memory 30.

In this embodiment, the process of S135~S195 are cuff pressure until _{P i} is less than K measured a predetermined lower limit value, is repeated for each pulse wave (S210). That is, in the process of reducing the cuff pressure, the volume pulse wave ΔV (P _i ) is calculated by the number n of pulse waves generated until the K measurement lower limit value is reached. In S210, if the cuff pressure is not equal to or less than K lower limit of measurement values, the value of i of _{P i} is one update, for example, the pulse wave when the _P i = P1 in the flow of the previous S135~S195 volume When the pulse wave ΔV is obtained, the volume pulse wave ΔV is obtained next time for the pulse wave when P _i = P2.

  In this flow, since the cuff control is performed for both blood pressure determination and blood vessel compliance measurement, the K measurement lower limit value is set to the lowest blood pressure value, but is not limited to this as long as it is a numerical value equal to or lower than the lowest blood pressure value. .

Further, in this embodiment, the volume pulse wave ΔV (P _i ) is calculated by the number n of pulse waves. However, when the measurement accuracy of the blood vessel compliance is not required so much, or the processing capability of the control unit 10 When the storage capacity of the memory 30 is limited, for example, the volume pulse wave ΔV (P _i ) may be calculated by skipping every two pulse waves. Further, in advance determined P _i (e.g., every P i ₌ 5 mmHg), may be calculated volume pulse wave to a pulse wave generated when it reaches the P _i of the cuff pressure is determined.

Measurement of When cuff pressure _{P i} is equal to or less than K measurement lower limit value in this flow (S210), the volume pulse [Delta] V _{(P i)} is terminated, the control unit 10 opens the exhaust valve 43, the solenoid valve 65b, respectively Control is performed (S220).

The K calculating means 12 calculates the blood vessel compliance K (P _i ) for each pulse wave based on the volume pulse wave ΔV (P _i ) obtained for each pulse wave in S140 and the blood pressure value obtained in S205. (S220). Since the change in the intravascular pressure is obtained by SBP-DBP, it is obtained by K (P _i ) = ΔV (P _i ) / (SBP-DBP). The obtained blood vessel compliance K (P _i ) is stored in the memory 30 (S225).

Then, the main flow S30, and vascular compliance K cuff pressure P _i is in the following mean blood pressure MBP, details of flow for the measurement of the pulse wave propagation velocity PWV, 10, will be described with reference to FIG.

Incidentally, the vascular compliance K is previously the convenience cuff pressure P _i is but until the time of diastolic blood pressure DBP is at least determined, for improved accuracy of the measurement, also measuring the pulse wave propagation velocity PWV simultaneously, cuff pressure P _i is assumed to start measuring from a point of mean blood pressure MBP. Thus, vascular compliance K is the cuff pressure P _i, sometimes measured value there is a plurality.

First, the control unit 10 instructs the exhaust valve drive circuit 44 to again close the exhaust valve 43 opened in the previous S215 (S300). Subsequently, the pump drive circuit 42 is instructed to start pump pressurization (S305). Here, the cuff pressure P _i of the reduced pressure in the pressurization or later is displayed on the display screen of the display / switch unit 20 (S310).

Control unit 10, based on the mean blood pressure MBP blood pressure determining means determines in S205 earlier, the cuff pressure _{P i} to the pump drive circuit 42 instructs the pump pressure until the MBP (S315). Cuff pressure _{P i} is Upon reaching MBP, instructs the pump pressure stop to the pump drive circuit 42 (S320).

  Thereafter, the control unit 10 instructs the exhaust valve drive circuit 44 to open / close the exhaust valve 43 to perform exhaust control (S325).

Here, the cuff pressure is determined whether the following K measured limit value (S330), be below K lower measurement limit value, based on the number of measurement points of the pulse wave propagation velocity PWV that predetermined cuff pressure P _i is Exhaust control is performed until a predetermined measurement pressure is reached (S340) (S325). When the predetermined measurement pressure is reached, the control unit 10 causes the exhaust valve drive circuit 44 to stop the exhaust control and the electromagnetic valves 65a and 65b. , 83 are closed (S345).

Thus, in a state where the cuff pressure is maintained for each predetermined measurement pressure (for example, every 10 mmHg), the K calculation means 12 repeats the flow of S145 to S195 for the pulse wave generated during that time, The volume pulse wave ΔV (P _i ) is calculated from the detection value of the downstream sensor 61 (S350), and each pulse wave is calculated based on the volume pulse wave ΔV (P _i ) and the previously obtained SBP-DBP. The blood vessel compliance K is calculated (S355).

  Further, during this time, the control unit 10 displays the pulse waveform extracted from the downstream sub-cuff 50 by the downstream pulse wave extraction circuit 62 and the pulse waveform extracted from the upstream sub-cuff 70 by the upstream pulse wave extraction circuit 82. At the same time, it is stored in the memory 30 (so that the correspondence between time and pressure value can be understood) (S360).

When you are finished storing in the memory 30, the control unit 10 to open the solenoid valve 65a, 65b, 83 (S365) , until the cuff pressure _{P i} reaches the next measurement point (S340), performs exhaust control (S325 ), The flow of S345 to S365 is repeatedly executed. When the measurement point reaches the K measurement lower limit (S330), the exhaust valve 43 is finally opened, and the measurement using the cuff is completed (S335). In this embodiment, the K measurement lower limit is set to 25 to 30 mmHg for convenience of measurement accuracy, but it is as low as possible as long as pulse wave detection with less noise and error factors can be detected from the sensor. It is desirable to be set to.

  Next, details of the flow for calculating the arteriosclerosis parameter in the main flow S40 will be described with reference to FIG.

First, the control unit 10 loads data (for example, blood vessel compliance K (P _i ), upstream pulse wave waveform, downstream pulse wave waveform for each measurement point) stored in the memory 30 (S400).

Of the loaded data, the blood vessel compliance K (P _i ) is calculated for each pulse wave until the cuff pressure P _i reaches at least the maximum blood pressure value to the K measurement lower limit value. Since the calculation is divided into two flows, it is necessary to summarize these as one pressure-dependent characteristic (S415, S420). FIG. 17 is a graph showing the relationship between all the measured vascular compliance K (P _i ) and pressure in this way (S425).

In FIG. 17, the horizontal axis of the graph is TP (= Pa−Pe), but P _i = Pe (external blood pressure) and Pa = SBP−DBP. Each _i is converted to TP. Since the measurement points are not continuous as a matter of course, statistical processing is performed in FIG. 17 (S415), and a quadratic linear approximation curve approximated based on the measurement values is added.

Next, based on the pulse wave waveform stored in S360, the PWV calculation means 13 of the control unit 10 calculates the pulse wave propagation velocity PWV (S410). Specifically First, after aligning the time axis of the pulse waveform of the upstream and downstream, calculates the same cuff pressure P _i at the detected inter delay time of pulse wave .DELTA.t1 (P _i).

  FIG. 18 (a) displays the upstream side pulse waveform A and the downstream side pulse waveform B on the same time axis for TP = 10 mmHg obtained by conversion from Pi on the same time axis. 18 (b) is a graph in which the waveform of one pulse wave is enlarged and displayed in FIG. 18 (a), and FIG. 18 (c) is a circle in FIG. 18 (b). It is an enlarged graph of the part enclosed by.

The vertices of the part surrounded by a circle in FIG. 18B indicate the start points of the same pulse wave. Therefore, the PWV calculation means 13 obtains the pulse wave propagation time Δt1 (P _i ) by obtaining the deviation between the start points of the upstream pulse wave and the downstream pulse wave in terms of time.

In the present embodiment, as shown in FIG. 18C, Δt1 (P _i ) = 10.25 msec is obtained. The pulse wave propagation time can be obtained by searching for a point where the time differential value of both pulse wave waveforms is 0 and calculating the time difference between the points. Further, the pulse wave propagation time may be obtained by other methods.

  In this embodiment, the distance between the upstream sub-cuff 70 and the downstream sub-cuff 50 is L = 90 mm between the center and the center. Therefore, in this embodiment, the pulse wave propagation speed PWV = L / L when TP is 10 mmHg. Δt1 (TP = 10) = 90 [mm] /10.25 [msec] = 878 [cm / sec].

In this manner, the pulse wave propagation velocity PWV, the cuff pressure _{P i} is mean blood pressure MBP until the K lower measurement limit value, determined in a predetermined measurement points per (e.g., every 10 mmHg) (S415, S420), the graph The displayed result is shown in FIG. 19 (S425). Incidentally, for the 19, the horizontal axis of the graph, have been translated to the TP from the cuff pressure P _i. In this embodiment, since the pulse wave velocity PWV is measured every 10 mmHg, statistical processing is performed (S415), and a linear linear approximation line approximated based on the measured value is added.

  It is possible to determine the degree of arteriosclerosis of the subject by comparing the value and slope of the PWV characteristic of the subject shown in FIG. 19 with FIG. 13 shown earlier and determining which straight line in FIG. It is. The plurality of PWV straight lines in FIG. 13 indicate that the degree of arteriosclerosis is higher as the slope of the straight line is larger and the absolute value of the pulse wave velocity PWV is higher overall. When the PWV characteristic of the subject in FIG. 19 is superimposed on the PWV straight line in FIG. 13, it can be clearly understood that the degree of arteriosclerosis of the subject is relatively high.

  As shown in FIG. 19, the linear linear approximation is performed and the PWV straight line is expressed as a function of pressure, whereby the PWV value at a predetermined pressure can be easily calculated. It is also possible to calculate the PWV (80) used for determining the degree of arteriosclerosis (S430). In this embodiment, since the blood vessel compliance K is also measured and displayed in an approximated state, K (80) can be obtained from the graph of FIG. 17, and the previous PWV (80) And comparative evaluation is possible.

  Furthermore, in this embodiment, in addition to PWV (80) and K (80), the stiffness parameter β can be obtained (S430).

Here, in the pipe law graph of FIG. 20, the blood vessel cross-sectional area is A, TP and blood vessel cross-sectional area A at arbitrary points are P ₀ and A ₀ , respectively, and between the blood vessel cross-sectional area A and TP (P) The following nonlinear tube law is established.

ln (P / P ₀ ) = β {A−A ₀ ) / A ₀ } ^1/2
P = P ₀ * exp {β (ΔA / A ₀ ) ^1/2 }
P _SYS = P _DIA * exp {β (ΔA / A _{P = DIA} ) ^1/2 }

Here, P _SYS = highest blood pressure value and P _DIA = lowest blood pressure value. Β can be calculated from the above equation.

Based on the pressure dependency characteristic of the pulse wave propagation velocity PWV obtained as described above, the graph of the pressure dependency characteristic of the blood vessel compliance K, PWV (80), K (80), β, and analysis can be performed based on these results. The obtained degree of arteriosclerosis (for example, hard, normal, and soft multi-step display) is displayed on the display screen of the display / switch unit 20 or printed out (S435).

  Finally, in this embodiment, the merit of being able to simultaneously measure the blood vessel compliance and the pulse wave propagation speed using the same blood pressure pulse wave inspection apparatus 1 will be described.

  It is known that a relationship of PWV = √A / ρK (A: blood vessel cross-sectional area, ρ: blood density) is established between the blood vessel compliance K and the pulse wave propagation velocity PWV. Further, it is known that a differential integral relationship is established between the pressure dependence characteristic of the blood vessel compliance K and the pipe law (pressure dependence characteristic of the blood vessel cross-sectional area A).

  Therefore, when the approximate curve of the vascular compliance K obtained as shown in FIG. 17 is integrated, a so-called tube law curve representing the relationship between the vascular cross-sectional area and TP as shown in FIG. 20 is obtained. As described above, it is one of the features of the present invention that the blood vessel cross-sectional area of the subject can be obtained from the blood vessel compliance by a non-invasive measurement method regardless of the anatomical / invasive method. Further, by calculating the above-mentioned √A / ρK using the blood vessel cross-sectional area A obtained from FIG. 20, the pulse wave propagation velocity PWV can also be obtained from the blood vessel compliance K.

  On the other hand, when the blood vessel compliance K and the pulse wave propagation velocity PWV are simultaneously measured at a certain TP value, the blood vessel cross-sectional area at the TP value can be obtained from the relational expression with the blood vessel cross-sectional area A described above. Thus, the tube law curve can be obtained only in a pressure region where TP is positive (intravascular pressure> external blood pressure).

  That is, the pulse wave propagation speed PWV obtained from the blood vessel compliance K is compared with the pulse wave propagation speed PWV obtained by dividing the distance between the cuffs by the pulse wave propagation time, thereby obtaining the blood vessel compliance K. And the pulse wave propagation velocity PWV can be verified, and the measurement accuracy can be improved.

  In addition, since the blood vessel compliance K and the pulse wave propagation velocity PWV are both measured by the same blood pressure pulse wave inspection apparatus 1, the mutual correlation is basically guaranteed and should not be correlated. If it is found, it is possible to improve the measurement accuracy and the completeness of the apparatus by tracing and verifying the possibility of a measurement error or a malfunction of the apparatus. In addition, since there is no need for a separate device and the blood vessel compliance K and the pulse wave propagation velocity PWV can be measured with a single device, there is no inconvenience for the subject.

Conventionally, the pulse wave velocity PWV can only be calculated at one specific pressure value, and the blood vessel compliance K is also calculated only at one specific pressure value, or the cuff pressure _Pi is the lowest. Since measurement was possible only in the range of blood pressure value to systolic blood pressure value, it was impossible to compare the blood vessel compliance K and the pulse wave velocity PWV with each other, and the consistency and correlation could not be verified. It was.

  However, in the present invention, not only pressure-dependent characteristics are required for both the pulse wave propagation velocity PWV and the blood vessel compliance K, but also the blood vessel compliance K is measured in the same range as the pressure range of the pulse wave propagation velocity PWV. Mutual comparison and verification can be performed.

  For example, FIG. 21 is a graph simultaneously showing the relationship between the blood vessel compliance K and the pulse wave propagation velocity PWV calculated from the blood vessel compliance K with TP. Actually, what is important as an index of the degree of arteriosclerosis is the range of TP> 0, and it is very significant that not only the pulse wave velocity PWV but also the blood vessel compliance K can be measured in this range.

In addition, the blood vessel compliance K, which could be measured only at TP <0 until now, can be measured at TP> 0, and the pulse wave propagation velocity PWV, which could be measured only at TP> 0 until now, is expressed as TP <0. Since it has been obtained even at 0, it is expected that the pulse wave velocity PWV at TP <0 will be verified and analyzed in the future, leading to the elucidation of arteriosclerosis.

  As described above, the embodiment of the blood pressure pulse wave inspection apparatus 1 has been described. However, the blood pressure pulse wave inspection apparatus of the present invention is limited to the blood pressure pulse wave inspection apparatus 1 having all of the configuration requirements described in the above embodiments. Instead, various changes and modifications are possible. Further, it goes without saying that such changes and modifications belong to the scope of the claims of the present invention.

  In this embodiment, the blood pressure is measured based on the pulse wave detected from the main cuff 40, and both the blood vessel compliance K and the pulse wave propagation velocity PWV are measured based on the pulse wave detected from the downstream sub-cuff 50. However, the blood pressure may also be measured by the downstream side cuff 50. However, since the main cuff 40 basically plays a role of blocking the blood flow of the subject with sufficient pressure, the main cuff 40 and the constituent means necessary for blood pressure measurement are essential for the blood pressure pulse wave examination apparatus. .

  Further, the blood vessel compliance K does not necessarily need to be measured on the downstream side in the blood flow direction, and the downstream sub-cuff 50 does not need to use both the blood vessel compliance K and the pulse wave velocity PWV. For example, the constant-capacity pulse wave generating unit 63 may be connected to the main cuff 40, and by applying to the main cuff a pressure change of a predetermined known volume that can detect a change in the blood vessel wall relative to the volume of the main cuff 40. The sensitivity of the main cuff 40 may be calculated based on the pulse wave detected from the main-side sensor 45 of the main cuff 40 and the known capacitance value, and thereby the blood vessel compliance K may be obtained.

  Further, for example, a cuff for measuring the blood vessel compliance K exclusively may be provided at a substantially intermediate point between the downstream sub-cuff 50 and the upstream sub-cuff 70, and the cuff may be connected to the constant volume pulse wave generation unit 63. In this case, if the pulse wave velocity PWV is also measured, the downstream sub-cuff 50 and the upstream sub-cuff 70 are also required, so that the three cuffs are fixedly arranged side by side on the inner peripheral side of the main cuff 40. Become. In the case of the above-described embodiment, only two cuffs are provided in the main cuff 40, which is advantageous in terms of manufacturability and manufacturing cost.

  The control unit 10 includes a blood pressure calculation unit 11 that calculates a blood pressure, a K calculation unit 12 and a PWV calculation unit 13. In addition, the control unit 10 includes a control necessary for calculating the blood vessel compliance K and the pulse wave propagation speed PWV, Needless to say, solenoid valve opening / closing control and the like associated with these measurements are also performed.

  The configuration of the constant-capacity pulse wave generation unit 63 described in the present specification is merely an example, and the configuration is implemented if it is a constant-capacity pump that plays a role of supplying a predetermined known volume of air to the cuff. It is not restricted to what was described in the example.

  In the embodiment, after storing the waveform data of the upstream pulse wave and the downstream pulse wave, the pulse wave propagation velocity PWV is calculated in S410 of FIG. 12, but the pulse wave propagation velocity PWV is calculated simultaneously with the waveform data storage. Calculation may be performed. The calculation of the blood vessel compliance K is performed only for the volume pulse wave ΔV first, and is stored in the memory 30 together with the downstream pulse wave waveform and the pulse wave amplitude value. The blood vessel compliance K may be calculated together with the wave propagation velocity PWV.

In the embodiment, in order to obtain the blood vessel compliance K in the period from when the cuff pressure _Pi reaches the maximum blood pressure value to the K measurement lower limit value, the measurement range of the pulse wave velocity PWV and the blood vessel compliance K are divided into two stages. the portion where the measurement range of the overlap has been adapted to measure the pulse wave propagation velocity PWV and blood vessel compliance K simultaneously, in a single process of changing the cuff pressure P _i, vascular compliance K full range is measured May be.

At that time, the pulse wave velocity PWV may also be measured from a predetermined cuff pressure value (for example, the average blood pressure value of a general subject is adopted as the predetermined cuff pressure value). May be determined). That way, once the process of changing the cuff pressure P _i, measurable PWV PWV and blood vessel compliance K is to be measured all, leading to shortening of the measurement time.

  In the embodiment, the measurement is performed in the process of gradually depressurizing after pressurizing the cuff to the maximum blood pressure value, but the measurement may be performed in the process of gradually pressurizing.

In the embodiment, every time the pulse wave extraction circuit extracts a pulse wave, the constant-capacity pulse wave generation unit 63 is driven or the blood vessel compliance K and the pulse wave propagation velocity PWV are measured. It is not necessary to perform these operations every time a pulse wave is extracted or every time a pulse wave is extracted at a predetermined interval. That is, the driving and the constant volume Ryomyaku wave generating unit 63, the measurement of vascular compliance K and PWV PWV is not need to be synchronized with the pulse wave extraction, predetermined cuff pressure every P _i (for example, every 10 mmHg) It may be performed every predetermined time (for example, every 0.5 ms), and the pressure characteristics of the blood vessel compliance K and the pulse wave propagation velocity PWV may be obtained accordingly.

  For example, the constant-capacity pulse wave generating unit 63 cuffs a pressure fluctuation of a known volume every predetermined time by using a clock signal having a constant cycle generated asynchronously with pulse wave extraction, regardless of pulse wave extraction. In addition, vascular compliance K may be measured when pressure fluctuations are applied. Even in this case, the pressure characteristic of the blood vessel compliance K can be obtained as long as the cuff pressure in the main cuff 40 is changed. Of course, when it is desired to measure the blood vessel compliance K with higher accuracy, the blood vessel compliance K may be obtained for each pulse wave with respect to all the extracted pulse waves as in this embodiment.

  Further, the constant-capacity pulse wave generating unit 63 does not need to be driven at the same time as the process of changing the cuff pressure of the main cuff 40 during blood pressure measurement. The cuff sensitivity may be measured by driving.

  In addition, in the embodiment, the predetermined known capacity applied by the constant-capacity pulse wave generating unit 63 is set to a value such that one pulse of a rectangular wave is output as shown in FIGS. For each pulse wave extraction, for example, by adding a stepped known capacity with different amplitude values to the cuff over a plurality of stages, calculating the cuff sensitivity for each stage, and performing an averaging process for each predetermined pulse wave, etc. The accuracy of cuff sensitivity is improved.

  Since the K calculating means 12 can calculate the blood vessel compliance K in real time whenever the cuff sensitivity and the amplitude value of the pulse wave are calculated in a specific pulse wave, the cuff pressure of the main cuff 40 is changed. In the process, the value of the blood vessel compliance K can be displayed on the display / switch unit 20 in real time, which is suitable for a home blood pressure pulse wave inspection apparatus that requires quickness and simplicity of measurement.

  Similarly, the PWV calculation means 13 can calculate the pulse wave propagation velocity PWV in real time every time a specific pulse wave is detected from the sub-cuffs 50 and 70, so that the cuff pressure of the main cuff 40 is changed. In the process, the value of the pulse wave propagation velocity PWV can be displayed on the display / switch unit 20 in real time.

In particular, in a home blood pressure pulse wave inspection device, when further rapidity and simplicity are required, the constant-capacity pulse wave generation unit 63 is driven at a specific cuff pressure P _{i at} one point or several points. The cuff sensitivity S _e (P _i ) obtained is used as a uniform value at the time of measurement (averaged when several points are measured), and the pressure characteristic of the vascular compliance K is calculated. You may ask for it.

In other words, in the present specification, “individual” of “measuring cuff sensitivity individually” has a broad meaning of “one measurement by one subject”, and every predetermined time or predetermined within one measurement. It means both of the meaning of every pulse wave detection or every predetermined cuff pressure.

It is a figure which shows the structure of the blood pressure pulse wave test | inspection apparatus of this invention. It is a figure which shows the cross-section of a cuff. It is a figure which shows the plane and side structure of a cuff. It is a graph which shows the damping characteristic by a pressure damper. It is a figure which shows the mechanical structure of a constant-capacity pulse wave generation unit. It is a figure which shows the main flow at the time of measuring arteriosclerosis using the blood pressure pulse wave test | inspection apparatus of this invention. It is a figure which shows the flow which measures blood pressure and blood vessel compliance. It is a figure which shows the flow which measures a volume pulse wave. It is a figure which shows the flow which measures blood pressure and blood vessel compliance. It is a figure which shows the flow which measures a blood vessel compliance and a pulse wave velocity. It is a figure which shows the flow which measures a blood vessel compliance and a pulse wave velocity. It is a figure which shows the flow which calculates an arteriosclerosis parameter. It is a graph which shows the relationship between a pulse wave propagation speed and blood pressure according to arteriosclerosis degree. It is the graph which recorded the pulse wave waveform detected with the sensor of the downstream subcuff for three pulse waves. It is the graph which expanded one pulse wave in the graph of FIG. It is a graph which shows the relationship between the pressure fluctuation amount of the pulse wave at the time of a constant capacity pulse wave generation unit drive, and cuff pressure. It is a graph which shows the relationship between vascular compliance and TP. It is the graph which displayed the upstream pulse wave waveform and the downstream pulse wave waveform on the same time axis when TP = 10 mmHg. It is a graph which shows the relationship between a pulse wave propagation velocity and TP. 18 is a tube law curve showing a relationship between a blood vessel cross-sectional area obtained by integrating the graph of FIG. 17 and TP. It is a graph which shows simultaneously the relationship between the pulse wave propagation velocity calculated by two calculation methods and TP.

Explanation of symbols

1: Blood pressure pulse wave test device 10: Control unit 11: Blood pressure calculation unit 12: K calculation unit 13: PWV calculation unit 20: Display / switch unit 30; Memory 40: Main cuff 40a: Outer cover 40b: Pressure damper 41: Pump 42 : Pump drive circuit 43: Exhaust valve 44: Exhaust valve drive circuit 45: Main side sensor 46: Main side pulse wave extraction circuit 50: Downstream side sub cuff 60: Downstream side pulse wave detector 61: Downstream side sensor 62: Downstream side pulse Wave extraction circuit 63: constant volume pulse wave generating unit 63a: air supply port 63b: back pressure intake port 63c: first closed space 63d: second closed space 63e: diaphragm
63f: Movable flange portion 63g: Coil 63h: Hall piece 63i: Magnet 63j: Yoke 64: Pulse wave generation drive circuit 65: Downstream solenoid valve 66: Air resistance 70: Upstream sub cuff 80: Upstream pulse wave detector 81: Upstream sensor 82: Upstream pulse wave extraction circuit 83: Upstream solenoid valve

Claims (8)

A main cuff wound around the subject,
In the process of changing the cuff pressure of the main cuff, a blood pressure pulse wave examination apparatus comprising blood pressure calculation means for measuring the highest blood pressure value SBP and the lowest blood pressure value DBP of the subject,
Two or more sub-cuffs provided on the inner peripheral side of the main cuff for detecting the pulse wave of the subject;
In the process of changing the cuff pressure of the main cuff, based on the amplitude value of the pulse wave detected by either the sub-cuff or the main cuff at every predetermined cuff pressure, every predetermined time or every predetermined pulse wave detection , K calculating means for calculating vascular compliance K which is an index of arteriosclerosis,
In the process of changing the cuff pressure of the main cuff, the propagation delay time between the pulse waves detected by any two of the sub-cuffs at every predetermined cuff pressure, every predetermined time, or every predetermined pulse wave detection, and between the sub-cuffs A blood pressure pulse wave examination apparatus comprising PWV calculation means for calculating a pulse wave propagation velocity PWV serving as an index of arteriosclerosis based on the predetermined distance of
The blood pressure pulse wave inspection device is
A constant-capacity pulse wave generation unit that applies pressure fluctuations of a predetermined known volume to the main cuff or sub-cuff every predetermined cuff pressure, every predetermined time, or every predetermined pulse wave detection;
The K calculating means calculates the sensitivity S of the cuff based on the pressure fluctuation amount of the pulse wave detected when the constant volume pulse wave generating unit is driven and the known capacitance value, and the sensitivity S and the pulse wave A blood pressure pulse wave inspection device , wherein the volume pulse wave ΔV is calculated based on an amplitude value ΔP . 2. The blood pressure pulse wave examination apparatus according to claim 1, wherein the constant-capacity pulse wave generation unit is controlled to be driven a predetermined time after the peak of the pulse wave is detected. The constant-capacity pulse wave generating unit includes an air supply port for supplying air to the cuff, a diaphragm forming a first closed space communicating with the air supply port, and vibrating the diaphragm to form the first The blood pressure pulse wave according to claim 1 or 2, further comprising: a movable flange portion that supplies a predetermined known volume of air in the enclosed space; and a coil that moves the movable flange portion up and down by energization. Inspection device. The constant-capacity pulse wave generation unit includes a back pressure inlet connected to the sub-cuff and the back pressure inlet connected to the main cuff, and a second closed space communicating with the back pressure inlet It is formed by the diaphragm, and the first closed space is controlled to be maintained at the same pressure as the second closed space until immediately before the constant-capacity pulse wave generating unit is driven. The blood pressure pulse wave inspection apparatus according to claim 3. The K calculating means calculates the blood vessel compliance K for each predetermined TP value (intravascular pressure−external blood pressure), and integrates the TP value to express the relation between the vascular cross-sectional area and the TP value. The blood pressure pulse wave examination apparatus according to any one of claims 1 to 4, wherein a curve is obtained. The PWV calculating means calculates the pulse wave propagation velocity PWV for each predetermined TP value (intravascular pressure-external blood pressure) to obtain a pressure dependency curve, and the tube law curve and the pulse wave propagation 6. The blood pressure pulse wave examination apparatus according to claim 5, wherein a correlation between the blood vessel compliance K and the pulse wave propagation velocity PWV is obtained by comparing a pressure dependence curve of the velocity PWV. The PWV calculation means and the K calculation means calculate the pulse wave propagation velocity PWV and the blood vessel compliance K, respectively, for each predetermined TP value (intravascular pressure-external blood pressure) to obtain a pressure dependence curve. 2. A blood vessel cross-sectional area is calculated from the pulse wave propagation velocity PWV and the blood vessel compliance K obtained simultaneously in step 1, and a tube law curve representing a relationship between the blood vessel cross-sectional area and the TP value is obtained. The blood pressure pulse wave inspection apparatus according to claim 6. The sub-cuff is fixed to the main cuff through a pressure damper that prevents mutual interference of detected pulse waves,
The pressure damper acts as a fixed end of the dynamic pressure of the sub-cuff and the main cuff accompanying the pulsation of the arterial pressure, and can isolate the pulsation of the pressure in the sub-cuff and the main cuff from each other, and the artery under the sub-cuff The blood pressure pulse wave inspection apparatus according to any one of claims 1 to 7, wherein only a volume fluctuation due to a pressure pulse wave of pressure can be detected.

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