JP4576114B2 - Biological measuring device - Google Patents

Description

  The present invention relates to a biological measurement apparatus that measures blood pressure and pulse wave velocity.

  In recent years, with the increasing aging society, early diagnosis and treatment of early treatment of arteriosclerotic diseases are urgently needed. To this end, first, it is necessary to correctly measure and evaluate how far arteriosclerosis has progressed.

  As a method for noninvasively diagnosing arteriosclerosis, a blood pressure test method for measuring blood pressure, and an aortic pulse for measuring a pulse wave velocity (PWV: Pulse Wave Velocity) between two points of the aorta Wave velocity inspection methods are known.

  Arteriosclerosis is often associated with hypertension, and blood pressure measurement is often performed as a basis for the diagnosis of arteriosclerosis, because arteriosclerosis tends to become hypertension as it progresses.

  Further, it is known that the pulse wave velocity is fast in a hard substance, slow in a soft substance, and a healthy artery wall is soft and elastic, and an arteriosclerotic blood vessel wall is hard and brittle. The aortic pulse wave velocity test method uses this property, and roughly speaking, the propagation velocity of the pulse wave between two points of the aorta is measured, and the higher the velocity, the more diagnosed the arteriosclerosis is. To do. This pulse wave velocity (PWV) is usually expressed in units of m / sec.

  As a typical blood pressure test, a cuff is wrapped around the arm, air is sent into the cuff, the arm is pressurized, and the pressure is gradually lowered while the pressure inside the cuff is caused by the pulse wave of the arm. A method of measuring systolic pressure (maximum blood pressure) and diastolic pressure (minimum blood pressure) by detecting changes in the blood pressure is often used.

  The pulse wave inspection method will be described with reference to the drawings.

  FIG. 1 is a schematic diagram illustrating an example of a pulse wave velocity measurement method. The pulse wave velocity measuring method shown in FIG. 1 is a measuring method called a Frank method.

  Here, as shown in FIG. 1A, two pulse wave sensors are used to measure the pulse waves of the carotid artery and the femoral artery, respectively. Further, distances a and b + c from the aortic valve opening to each pulse wave measurement point are measured. The measurement between the aortic valve opening and the pulse wave sensor for measuring the femoral artery with a broken line (distance b and distance c) without taking a straight line is based on a path along which the aorta extends.

  FIG. 1B shows the carotid artery wave (a) and the femoral artery wave (b) measured by each pulse wave sensor.

  A time T between predetermined rising points of these pulse waves, for example, points rising by 1/5 of the peak value is obtained.

  Thus, by obtaining the distances a, b, c and time T, the pulse wave velocity PWV is

Is required.

  Patent Document 1 discloses an improved technique based on the above pulse wave velocity measurement method. In Patent Document 1, pulse waves of the brachial artery and ankle arteries are measured instead of the pulse waves of the carotid artery and the femoral artery.

  FIG. 2 is a schematic view showing another example of the pulse wave velocity measuring method. The pulse wave velocity measuring method shown in FIG. 2 is a measuring method called the Yoshimura method.

  Similar to the Frank method shown in FIG. 1, in addition to the two sensors for measuring the pulse waves of the carotid artery and the femoral artery, sensors are also arranged at the aortic valve opening to measure the starting point of the II sound. Further, the linear distance D between the aortic valve opening and the femoral artery pulse wave measurement sensor is measured. In order to correct the difference between the straight line distance D and the actual path of the artery, the straight line distance D is multiplied by 1.3.

  In addition, the time T from the rising timing of the carotid artery wave to the rising edge of the femoral artery wave and the timing of the II sound of the aortic valve opening shown in FIG. The time t until the timing when the sound is captured is measured.

  Thus, by calculating the linear distance D and the times T and t, the pulse wave velocity PWV is

Is required.

  Here, the pulse wave velocity varies depending on the blood pressure. This is because when the blood pressure rises, the blood vessel is pushed and expanded by the blood, and the blood vessel is apparently hardened.

  FIG. 3 is a graph showing the relationship between minimum blood pressure (diastolic pressure) and aortic pulse wave velocity. FIG. 3 shows the relationship between the minimum blood pressure (diastolic pressure) and the aortic pulse wave velocity in 73 cases.

  As shown in FIG. 3, when the blood pressure increases, the aortic pulse wave velocity also increases.

  FIG. 4 is a diagram showing a pulse wave velocity correction curve.

  As shown in FIG. 3, the pulse wave velocity changes depending on the blood pressure. Therefore, a large number of cases as shown in FIG. 3 are statistically analyzed, and a pulse wave velocity correction curve is obtained as shown in FIG. In actual measurement, the pulse wave velocity is measured and the blood pressure is measured, and the measured pulse wave velocity is converted into the pulse wave velocity when the minimum blood pressure (diastolic pressure) is 80 mmHg according to the pulse wave velocity correction curve shown in FIG. To do.

  Also in Patent Document 1, this blood pressure correction is performed.

  By doing so, it does not depend on the blood pressure at the time of measuring the pulse wave of the case. The pulse wave velocity of the case is obtained, and atherosclerosis is diagnosed based on the pulse wave velocity.

  In Patent Document 2, for example, both the blood pressure and the pulse wave velocity are measured as described above, and a normal range, a caution range, and a warning range are defined for arteriosclerosis on a two-dimensional plane composed of the blood pressure and the pulse wave velocity. It has been proposed. This Patent Document 2 describes that a pulse wave is detected by using a cuff at the time of measuring a pulse wave velocity, pressurizing to 60 mmHg lower than the lowest blood pressure measured by sending air into the cuff.

  In Patent Document 3, a pulse wave is first detected to obtain a pulse wave velocity (PWV), and based on the PWV, it is determined whether or not the artery has a stenosis. It describes the measurement of blood pressure.

Further, Non-Patent Document 1 is cited for later explanation.
Japanese Patent No. 3140007 JP 2003-126054 A JP 2002-272688 A land Asmar, Michael F.L. O'Rourke, Michel Safari 1999 Editions scientifics ethicals Elsevier SAS

  Here, when measuring both the pulse wave velocity and the blood pressure, the cuff is used to measure both, and the measurement site can be pressurized with the cuff and the change in pressure can be detected. In that case, the problem is how to accurately measure both blood pressure and pulse wave velocity, and efficiently measure in as short a time as possible.

  An object of this invention is to provide the bioinstrumentation apparatus which can perform an appropriate measurement in view of the said situation.

First living body measuring device of the biometric measuring device of the present invention to achieve the above SL objects, in living body measuring device for measuring the pulse wave velocity, is wound is fed air to each of the arms and legs Four cuffs that pressurize each wound part, a cuff pressure control unit that controls the pressure inside the cuff by sending air into the cuff to the pressure received, and cuff pressure control during pulse wave velocity measurement Sequence control unit for instructing the unit to pressurize the pressure of four cuffs wound around both arms and both feet at the same time only one arm of both arms and one of both feet It is provided with.

In the case of measuring the pulse wave velocities of a plurality of blood vessels, conventionally, the limbs (both arms and both legs) are pressurized simultaneously, and the pulse wave velocity is measured from the pulse wave (PVR) obtained from the cuff. However, if the limbs are pressurized simultaneously, the blood vessels are compressed or occluded, which may affect the state of the living body being measured. In the first living body measuring apparatus of the present invention, the pulse wave velocity is sequentially measured without applying pressure simultaneously, so that the pulse wave velocity is sequentially measured. Can be measured accurately.

Furthermore, the second living body measuring device of the living body measuring device of the present invention is a living body measuring device that measures blood pressure and pulse wave velocity, and air is wound around both arms and at least one leg. At least three cuffs that pressurize each part wound by being sent in, a cuff pressure control unit that sends air into the cuff and controls the pressure in the cuff to the pressure that is instructed, and a cuff pressure control unit, Instruct the pressure of each cuff so that one arm and one leg of both arms are pressurized for pulse wave velocity measurement and the other arm of both arms is pressurized for blood pressure measurement And a cuff pressure instruction unit.

In the case of the second living body measurement apparatus of the present invention, since the blood pressure is measured by the other of the left and right while pressing one of the left and right of both arms for pulse wave velocity measurement, both the pulse wave velocity and the blood pressure are accurately detected. In addition, it is possible to reduce the burden on the living body by performing measurement in a short time by simultaneous measurement.

  As described above, according to the present invention, both blood pressure and pulse wave velocity can be measured appropriately.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 5 is a block diagram showing the configuration of the biological measurement apparatus according to the embodiment of the present invention.

  The living body measurement apparatus 100 shown in FIG. 5 includes four cuffs 1R, 1L, 2R, and 2L. Here, the cuffs 1R, 1L, 2R, and 2L are cuffs for the right arm, the left arm, the right ankle, and the left ankle, respectively. The cuffs 1R, 1L, 2R, and 2L are provided with air bags 1R11, 1L11, 2R11, and 2L11, respectively, and the cuffs 1R, 1L, 2R, and 2L are wound around the respective portions and the cuff pressure control units 1R12, 1L12 are provided. , 2R12, 2L12, air is sent into the air bags 1R11, 1L11, 2R11, 2L11, and each part is compressed by 1R, 1L, 2R, 2L. The cuff pressure control units 1R12, 1L12, 2R12, and 2L12 have a function of increasing the pressure of each cuff 1R11, 1L11, 2R11, and 2L11 to a target value, a function of maintaining the pressure of the target value, and cuffing at an instructed speed. And a function to lower the pressure.

  5 includes a heart sound microphone 131 and a heart sound detection unit 13 for detecting a heart sound from the heart sound microphone 131. Furthermore, an electrocardiogram detection electrode 141 and its electrode 141 are provided. An electrocardiogram detection unit 14 for detecting an electrocardiogram due to is provided.

  In addition, an arithmetic control unit 30 is provided here, and the arithmetic control unit 30 instructs the cuff pressure control units 1R12, 1L12, 2R12, and 2L12 to specify the target value of the cuff pressure, and the detected pulse wave data. In addition, it is responsible for the overall control and calculation of the biological measuring apparatus 100, such as performing calculations by taking heart sound data and electrocardiogram data. The arithmetic control unit 30 further includes a display unit 16 for performing various displays, a recording unit 17 for printing measurement results and the like, a storage unit 18 for storing various measurement data, and a signal indicating completion of measurement and a warning. A sound generator 19 and a communication unit 20 that communicates with another device 200 as necessary are connected. These units 16 to 20 operate according to the control of the arithmetic control unit 30.

  Further, an input / instruction unit 21 for performing various inputs and instructions to the biological measurement apparatus 100 is provided here. The arithmetic control unit 30 controls each unit in accordance with the input / instruction from the input / instruction unit 21.

  FIG. 6 is a diagram illustrating a configuration of a cuff pressure control unit included in the living body detection apparatus 100 of FIG.

  The cuff 10 shown in FIG. 6 represents only one of the four cuffs 1R, 1L, 2R, and 2L shown in FIG. 5, and the cuff pressure control unit 12 shown in FIG. Only one cuff pressure control unit 1R12, 1L12, 2R12, 2L12 is shown as a representative.

  The cuff pressure control unit 12 includes a control unit 121, a pump drive unit 122, a pump 123, an exhaust valve control unit 124, an exhaust valve 125, a pressure sensor 126, and an amplifier 127. 10 air bags 11 are connected by an air hose 128.

  The cuff pressure control unit 12 receives a cuff pressure control signal representing a target value of the cuff pressure from the arithmetic control unit 30 shown in FIG. The control unit 121 gives an instruction to the pump drive unit 122 to drive the pump 123 by the pump drive unit 122 to send air into the air bag 11 of the cuff 10. The pressure (cuff pressure) of the air bladder 11 is detected by the pressure sensor 126, appropriately amplified by the amplifier 127, and transmitted to the control unit 121. The control unit 121 causes the pump control unit 122 to drive the pump 123 until the cuff pressure detected by the pressure sensor 126 reaches the target value indicated by the cuff pressure control signal from the calculation control unit 30 (see FIG. 5). This target value is, for example, 200 mmHg during blood pressure measurement, and is 40 mmHg or less, 10 mmHg or more, for example, 30 mmHg, during pulse wave velocity measurement.

  At the time of blood pressure measurement, the cuff pressure is temporarily increased to, for example, 200 mmHg, and then the exhaust valve control unit 124 is opened to the exhaust valve 125 to reduce the cuff pressure at a predetermined speed, for example, 3 mmHg / sec. When is finished, the remaining cuff pressure is reduced to atmospheric pressure at once.

  At the time of measuring the pulse wave velocity, the cuff pressure is maintained at a constant pressure such as 30 mmHg and lowered to the atmospheric pressure after the pulse wave is detected.

  In both the blood pressure measurement and the pulse wave detection, the pressure sensor 126 captures a minute change in pressure due to the pulse wave, thereby detecting the blood pressure and the pulse wave.

  Hereinafter, various sequences of blood pressure measurement and pulse wave velocity measurement by the biological measurement apparatus 100 described with reference to FIGS. 5 and 6 will be described. Various sequences described below are switched by an instruction from the input / instruction unit 21 shown in FIG.

  FIG. 7 is a flowchart showing a first sequence when blood pressure measurement and pulse wave velocity measurement are performed, and FIG. 8 is a diagram showing a change in cuff pressure during measurement according to the first sequence shown in FIG.

  Here, two of the four cuffs 1R, 1L, 2R, and 2L shown in FIG. 1 are used, and the cuff 1R is wound around the right arm and the cuff 2R is wound around the right ankle for measurement.

  Here, after the cuffs 1R and 2R are wound around the right arm and the right ankle, respectively, according to the first sequence, first, 1R and 2R are pressurized to a target value of cuff pressure for pulse wave velocity measurement, for example, 30 mmHg (step) a1) The pulse wave velocity PWV is measured from the pulse waves of the two cuffs 1R and 2R (step a2), and the two cuffs 1R and 2R are depressurized to atmospheric pressure (step a3). Subsequently, the cuff 1R wound around the right arm is now pressurized to, for example, 200 mmHg for blood pressure measurement (step a4), and blood pressure is measured while gradually decreasing the cuff pressure of the cuff 1R (step a5). The cuff pressure of the rear cuff 1R is reduced to atmospheric pressure (step a6). Thereafter, calculation based on PWV and blood pressure obtained by the current measurement, display of the measurement data, and the like are performed (step a7). An example of the calculation performed in step a7 will be described later.

  In the case of the first sequence shown in FIG. 7, the pulse wave measurement is performed first, followed by blood pressure measurement. Since the pulse wave measurement is performed prior to the blood pressure measurement with a high cuff pressure, the pulse wave measurement is accurately performed. In addition, since the blood pressure measurement is performed immediately after the pulse wave measurement without waiting until it is determined whether or not there is a stenosis after the pulse wave measurement in Patent Document 3, both the pulse wave measurement and the blood pressure are measured. This measurement can be done in a short time, and the patient is not burdened so much.

  When performing measurement according to the first sequence shown in FIG. 7, the cuff pressure at the time of measuring the pulse wave velocity is set to a cuff pressure within the range of 40 mmHg or less and 10 mmHg or more indicated by the input / instruction unit 21.

  FIG. 9 is a flowchart showing a second sequence when blood pressure measurement and pulse wave velocity measurement are performed.

  Here, as in the case of the measurement according to the first sequence shown in FIG. 7, two of the four cuffs 1R, 1L, 2R, and 2L shown in FIG. 5 are used, and the right arm of the cuff 1R is wound, The cuff 2R is wound around the right ankle and measured.

  In performing measurement, first, the cuff 1R wound around the right arm is pressurized to, for example, 200 mmHg for blood pressure measurement (step b1), blood pressure is measured while gradually decreasing the cuff pressure (step b2), and the cuff after blood pressure measurement is measured. The 1R cuff pressure is reduced to atmospheric pressure (step b3). After that, the system waits for a standby time in which an instruction is input in advance from the input / instruction unit 21 (step b4). This is to wait until the influence of pressing the right arm during blood pressure measurement is settled and an accurate pulse wave velocity measurement can be performed.

  After the waiting time has elapsed, the cuff 1R wound on the right arm and the cuff 2R wound on the right ankle are at least 20 mmHg lower than the diastolic pressure (minimum blood pressure) of the blood pressure measured this time, for example, the diastolic period When the pressure is 65 mmHg, the pressure is 45 mmHg or less, for example, 40 mmHg or 30 mmHg. At this time, if the cuff pressure is controlled to be 40 mmHg or more lower than the diastolic pressure, it is preferable that the blood pressure is further reduced during the pulse wave velocity measurement. The lower limit value of the cuff pressure is such that a pulse wave can be detected, that is, about 10 mmHg.

  When the cuff pressures of the two cuffs 1R and 2R are increased to a target value (for example, 40 mmHg) in step b5, PWV is measured from the pulse waves of the two cuffs 1R and 2R while maintaining the state (step b6) Thereafter, the cuff pressures of the two cuffs 1R and 2R are reduced to the atmospheric pressure (step b7), and calculation and display are performed (step b8). A calculation example of step b8 will be described later.

  Here, blood pressure is measured first, and the cuff pressure at the time of measuring the pulse wave velocity is obtained from the diastolic pressure obtained by the blood pressure measurement. In this case, the cuff pressure at the time of measuring the pulse wave velocity can be appropriately determined according to the blood pressure at that time. However, if the pulse wave velocity measurement is performed immediately after blood pressure measurement, there is a risk that the pulse wave may not be detected accurately due to the pressure on the right arm during blood pressure measurement, so remove the adverse effect by waiting for the specified time after blood pressure measurement. Yes.

  FIG. 10 is a flowchart showing a third sequence when blood pressure measurement and pulse wave velocity measurement are performed.

  Here, the four cuffs 1R, 1L, 2R, and 2L shown in FIG. 5 are used, and these four cuffs 1R, 1L, 2R, and 2L are wound around the right arm, the left arm, the right ankle, and the left ankle, respectively. Measurement is performed using 1R, 1L, 2R, and 2L.

  Here, first, the cuff 1R wound around the right arm and the cuff 2R wound around the right ankle are pressurized to a target value for pulse wave measurement, for example, 20 mmHg (step c1), and the pulse waves of the two cuffs 1R and 2R are PWV is measured (step c2), and then the cuff pressures of the two cuffs 1R and 2R are reduced to atmospheric pressure (step c3).

  Next, pressurize the cuff 1L wound around the left arm and the cuff 2L wound around the left ankle to the target value, for example, 20 mmHg (step c4), and measure the PWV from the pulse waves of the two cuffs 1L and 2L. (Step c5) Then, the cuff pressures of the two cuffs 1L and 2L are reduced to atmospheric pressure (step c6). Subsequently, the cuff 1R wound around the right arm is pressurized to, for example, 200 mmHg for blood pressure measurement (step c7), blood pressure is measured while gradually decreasing the cuff pressure of the cuff 1R (step c8), and diastolic pressure When the measurement is completed, the cuff pressure of the cuff 1R is reduced to atmospheric pressure (step c9), and calculation / display and the like are performed (step c10). A calculation example of step c10 will be described later.

  Here, the PWV is measured from the pulse waves of the right arm and right ankle, and the PWV is also measured from the pulse waves of the left arm and left ankle. Alternatively, the adverse effects of occlusion are minimized and accurate measurements are made.

  In the third sequence shown in FIG. 10, blood pressure measurement is performed with only the right arm, but it may be performed with both the right arm and the left arm.

  FIG. 11 is a flowchart showing a fourth sequence when blood pressure measurement and pulse wave velocity measurement are performed, and FIG. 12 is a diagram showing temporal changes in cuff pressure when measurement is performed according to the fourth sequence.

  Here, three cuffs 1R, 1L, 2R out of the four cuffs 1R, 1L, 2R, 2L shown in FIG. 5 are used, and each cuff 1R, 1L, 2R is wound around the right arm, left arm, and right ankle, respectively. To do.

Here, first, the cuff 2R wound on cuff 1R and right ankle wound on the right arm, pressurized to the as example 10mmHg target value at the time of the pulse wave velocity measurement (step d1), further, cuff 1L wound on the left arm Is cuff pressure at the time of blood pressure measurement, for example, to 200 mmHg (step d2), and PWV is measured from the pulse waves of the cuffs 1R and 2R wound around the right arm and the right ankle, and at the same time the cuff of the cuff 1L wound around the left arm Blood pressure is measured while gradually reducing the pressure (step d3). Thereafter, the cuff pressures of the three cuffs 1R, 1L, and 2R are reduced to atmospheric pressure (step d4), and calculation and display are performed (step d5). A calculation example will be described later.

  According to the fourth sequence shown in FIG. 11, both PWV and blood pressure are measured at the same time without adversely affecting each other, and therefore the time required for measurement is short.

  Next, an example of operations (steps a7, b8, c10, d5) in the first to fourth sequences shown in FIGS. 7 and 9 to 11 will be described.

  Here, the following calculation is performed using both the measured PWV and blood pressure, and an evaluation value representing the degree of sclerosis of the blood vessel is obtained and displayed.

  The pulse wave velocity (PWV) measured as described above can be obtained with sufficient accuracy using the Moens-Korteweg equation.

It is known that it can be represented by the above (see Non-Patent Document 1 mentioned above). Here, k is a constant, and D / ΔD is a blood vessel elastic modulus (D: blood vessel diameter, ΔD: displacement of the blood vessel diameter).

Regarding the blood vessel diameter and blood pressure, the formula (D / ΔD) · ln (Ps / Pd) = β (constant) (4)
Is known to hold (see Non-Patent Document 1 above).

  Here, D / ΔD is the blood vessel elastic modulus (D: blood vessel diameter, ΔD: displacement of blood vessel diameter) as in the case of the expression (3), and Ps and Pd are systolic pressure (maximum blood pressure), Diastolic pressure (minimum blood pressure). This β is a constant value for a blood vessel of a specific part of a specific case, and when the blood pressure of that part of the case changes, the blood vessel diameter changes so as to keep the value β constant. Yes.

  Conventionally, both of the above formulas (3) and (4) have been known, but by combining these formulas (3) and (4), the drawback of the pulse wave velocity inspection method, that is, measurement It was necessary to correct the pulse wave velocity using a correction curve as shown in FIG. 4, so that it was possible to overcome the drawback that only a pulse wave velocity test of a specific part could be performed. There are no examples.

Therefore, here, when the above equation (3) is squared and the equation (4) is substituted for D / ΔD in the squared equation (3),
PWV ² · ln (Ps / Pd) = k ² β (5)
This equation (5) only measures PWV, measures blood pressure (systolic pressure (maximum blood pressure) Ps and diastolic pressure (minimum blood pressure) Pd), and substitutes these measurement results into equation (5). This means that k ² β, which is a value corresponding to the measurement site, can be obtained without performing correction according to the correction curve as shown in FIG. In other words, the expression (5) can be adopted as an evaluation value for diagnosing the degree of progression of arteriosclerosis. In order to obtain the evaluation value k ² β, the PWV measurement and the blood pressure measurement are performed as in the conventional case. And that is enough.

  When the inspection method according to the equation (5) is adopted, it is not necessary to obtain a correction curve as shown in FIG. 4 in advance and correct the correction based on the curve. Can also be applied.

Here, it has been explained that PWV, Ps, and Pd are measured and k ² β is obtained according to the equation (5). Instead of obtaining k ² β, k is a known constant, and therefore β can be obtained. Alternatively, an arithmetic expression for obtaining a value affected by the left side PWV ² · ln (Ps / Pd) of the expression (5) may be defined, and a value according to the arithmetic expression may be obtained.

Here, first, as a first step, the evaluation value V1 is
V1 = ln (Ps / Pd) · 1 / k ² · PWV ² (6)
Define with the following formula.

  Here, Ps and Pd are the systolic pressure and diastolic pressure of the measurement target region, k is a known constant, and PWV is the pulse wave velocity of the measurement target region. Here, the pulse wave velocity PWV substituted into the equation (6) is a pulse wave velocity before correction by blood pressure (see FIG. 4).

  FIG. 13 is a diagram showing a correspondence relationship between the pulse wave velocity as the conventional method and the evaluation value V1 based on the above equation (6). The horizontal axis is the pulse wave velocity when the diastolic pressure (minimum blood pressure) is 80 mmHg corrected according to the correction curve shown in FIG. 4, and the vertical axis is the evaluation value V1 calculated based on the equation (6). . Each plotted point represents one case.

  The relationship between the evaluation value V1 and PWV is approximated by a straight line as shown in FIG. Further, coordinate transformation is performed so that the straight line passes through the origin and becomes a 45 ° diagonal line.

  FIG. 14 is a diagram showing a correspondence relationship between the pulse wave velocity (horizontal axis) according to the conventional method and the evaluation value V2 (after coordinate conversion) after such coordinate conversion is performed.

  Here, the pulse wave velocity measuring method described with reference to FIG. 1 and FIG. 2 is a measuring method for measuring pulse waves in the carotid artery and femoral artery, but each case shown in FIGS. 2 shows the correlation between PWV obtained by the measurement method described with reference to 2 and V1 obtained using the expression (6) or V2 obtained using the following expression (7).

  Here, for both ankle arteries, pulse waves are measured, and for the other, T + t when the carotid pulse wave is measured and when the brachial artery pulse wave is measured (FIG. 2B). Reference time will be described.

  FIG. 15 is a graph showing the relationship between time (T + t) (horizontal axis) when measuring the carotid artery pulse wave and time (vertical axis) of T + t when measuring the brachial artery pulse wave.

  Although the time on the horizontal axis and the time on the vertical axis are quite approximate, there are some differences.

  Therefore, considering these, as the evaluation value V2,

Is adopted.

Here, L is the blood vessel length in the pulse wave velocity measurement section, and a, b, a1, and b1 are linear equations shown in FIG.
y = ax−b
And the equation of the straight line shown in FIG. 15 is y = a1 · x + b1
Are the values a, b, a1 and b1.

In the examples shown in FIGS. 13 and 15, respectively.
a = 2.6908
b = 13.707
a1 = 0.9872
b1 = 0.7627
It is.

  When the arithmetic expression shown in the equation (8) is adopted, when the pulse wave of the brachial artery is measured instead of the carotid artery, the value is equivalent to that when the carotid artery is measured, and the conventional PWV (minimum blood pressure) An evaluation value V2 having a value equivalent to (converted to 80 mmHg) is calculated.

  Although the evaluation value V1 represented by the above expression (6) may be adopted as the evaluation value of the degree of hardening of the blood vessel, it is more preferable to adopt the evaluation value V2 represented by the expression (7). This is because, if a calculation formula is defined so that the same evaluation value as that of the conventional PWV is obtained when the degree of vascular hardening is the same, it is possible for doctors who are accustomed to the value of the conventional PWV. This is because it is easy to diagnose various diseases associated with arteriosclerosis with reference to the evaluation value.

  Next, blood pressure when obtaining an evaluation value using equation (6) or equation (7) will be described.

  So far, it has been explained that the blood pressure (systolic pressure Ps and diastolic pressure Pd) of the measurement target region is measured and the blood pressure is substituted into the equation (6) or (7). The problem is which point of blood pressure is to be substituted. Specifically, it is preferable to adopt the blood pressure at the center point of the section in which the pulse wave velocity PWV is measured, but for example, the blood pressure value of the upper arm may be substituted.

  The evaluation value obtained in this way is displayed on the display unit 16 shown in FIG. 1 or printed out by the recording unit 17 to be used for diagnosis of arteriosclerosis.

It is a schematic diagram which shows an example of the pulse wave velocity measuring method. It is a schematic diagram which shows another example of the pulse wave velocity measuring method. It is a graph which shows the relationship between minimum blood pressure (diastolic pressure) and aortic pulse wave velocity. It is the figure which showed the pulse wave velocity correction curve. It is a block diagram showing the structure of the bioinstrumentation apparatus of one Embodiment of this invention. It is a figure which shows the structure of the cuff pressure control part which comprises the living body detection apparatus of FIG. It is a flowchart which shows the 1st sequence when performing a blood pressure measurement and a pulse wave velocity measurement. It is a figure which shows the change of the cuff pressure during measuring according to the 1st sequence shown in FIG. It is a flowchart which shows the 2nd sequence when performing blood pressure measurement and pulse wave velocity measurement. It is a flowchart which shows the 3rd sequence when performing blood pressure measurement and pulse wave velocity measurement. It is a flowchart which shows a 4th sequence when performing a blood pressure measurement and a pulse wave velocity measurement. It is a figure which shows the time change of the cuff pressure when measuring according to a 4th sequence. It is a figure which shows the correspondence of the pulse wave velocity as a conventional method, and the evaluation value V1 based on said (6) Formula. It is a figure which shows the correspondence of the pulse wave velocity (horizontal axis) by a conventional method, and evaluation value V2 (after coordinate conversion). It is a graph which shows the relationship between time (T + t) (horizontal axis) when measuring the pulse wave of the carotid artery and T + t time (vertical axis) when measuring the pulse wave of the brachial artery.

Explanation of symbols

1R, 1L, 2R, 2L Cuff 1R11, 1L11, 2R11, 2L11 Air bag 1R12, 1L12, 2R12, 2L12 Cuff pressure controller 10 Cuff 11 Air bag 12 Cuff pressure controller 13 Heart sound detector 131 Heart sound microphone 14 Electrocardiograph detector 141 Electrode 16 Display Unit 17 Recording Unit 18 Storage Unit 19 Sound Generation Unit 20 Communication Unit 21 Input / Instruction Unit 30 Arithmetic Control Unit 100 Biological Measuring Device 121 Control Unit 122 Pump Drive Unit 123 Pump 124 Exhaust Valve Control Unit 125 Exhaust Valve 126 Pressure Sensor 127 Amplifier 128 Air hose 200 Other devices

Claims (2)

In the biological measurement device that measures the pulse wave velocity,
Four cuffs that pressurize each wound part by being wound around each arm and both legs and being fed with air,
A cuff pressure control unit that sends air into the cuff to control the pressure in the cuff to the pressure received by the instruction;
At the time of measuring the pulse wave velocity, the cuff pressure control unit applies the pressures of the four cuffs wound around both arms and both feet, and at the same time, only one arm of both arms and only one of the two feet. A biological measurement apparatus comprising a sequence control unit that instructs to be pressurized. In a biological measurement device that measures blood pressure and pulse wave velocity,
At least three cuffs that pressurize each wound part by being wound around each of the arms and at least one of the legs and being fed with air;
A cuff pressure control unit that feeds air into the cuff and controls the pressure in each cuff to the pressure received.
One arm and one leg of the arms are pressurized for pulse wave velocity measurement and the other arm of the arms is pressurized for blood pressure measurement by the cuff pressure control unit. And a cuff pressure indicating unit for indicating the pressure of each cuff .

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