JP2007135966A - Device for measuring degree of vascular stiffness and blood pressure measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for measuring a degree of vascular stiffness without depending on a blood pressure value in principle. <P>SOLUTION: A differentiation wave form is formed by computing a first differentiation value by performing temporal differentiation on pulse wave components of a cuff pressure. The differentiation wave form from almost the peak point of the differentiation wave form to a point where the value of the differentiation wave form becomes almost 0 is subjected to integration to obtain a changed portion dP1 of the cuff pressure by a first pulse wave. Next, the device for measuring a degree of vascular stiffness obtains a changed portion dP2 of the cuff pressure by a second pulse wave and sequentially obtains up to the changed portion dPn of the cuff pressure by the nth pulse wave. Then, the device converts the changed portions dP1-dPn to volumetric changes of the blood vessels based on the Boyle-Charle's law, and computes a ratio of two predetermined compliances after obtaining each compliance. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a blood vessel sclerosis measuring apparatus.

  Conventionally, when measuring the degree of vascular stiffness, pulse wave velocity (PWV) measurement is known.

In recent years, using ultrasonic CT, the blood vessel thickness and the amount of change thereof are measured non-invasively, and image processing is performed to reduce blood vessel compliance (changes in blood vessel volume with respect to blood vessel internal and external pressure differences). A measuring method is known (see, for example, Patent Document 1).
JP 60-220037 A

  Conventionally, when measuring the degree of vascular sclerosis, it is measured without applying external pressure. That is, both the pulse wave velocity (PWV) measurement and the ultrasonic CT are measured in a state where the internal / external pressure difference of the blood vessel is high. Therefore, a value measured in a region where the characteristic of the outer membrane of the blood vessel is dominant is obtained.

  FIG. 14 is a diagram showing the relationship between the internal / external pressure difference Pt and the blood vessel volume (volume per unit length of blood vessel) V in the conventional example.

  On the other hand, as shown in FIG. 14, the pressure-volume characteristic of a blood vessel has a non-linear characteristic that compliance is large at low pressure, and compliance is reduced when the internal pressure is increased. This non-linear characteristic depends on the physical structure of the blood vessel.

  The “compliance” is dV / dPt, that is, the change rate of the volume of the blood vessel with respect to the intra-vascular external pressure difference.

  In the conventional vascular sclerosis measuring device, the compliance when the blood pressure is high (A) is different from the compliance when the blood pressure is low (A ′). That is, there is a problem that the higher the blood pressure at the time of measurement, the higher the measured degree of cure.

  On the other hand, there is a medical opinion that the degree of sclerosis of blood vessels should be mainly evaluated with the media. However, both conventional examples have a problem that they cannot be evaluated with the media.

  Further, since the compliance is different depending on the thickness of the blood vessel, it is medically problematic to use it as it is as an index representing the degree of hardening of the blood vessel.

  Furthermore, in the above conventional example, since the degree of vascular sclerosis cannot be measured simultaneously with the blood pressure measurement, there is also a problem that the measured degree of vascular sclerosis cannot be corrected with the blood pressure.

An object of the present invention is to provide a vascular sclerosis degree measuring apparatus capable of measuring a vascular sclerosis degree independent of a blood pressure value in principle.

In the present invention, the pulse wave component of the cuff pressure is time-differentiated to calculate a primary differential value, a differential waveform is formed, and the value of the differential waveform is substantially zero from the time when the formed differential waveform is substantially peak. The differential waveform up to is integrated to obtain the change cP pressure dP1 due to the first pulse wave, then the cuff pressure change dP2 due to the second pulse wave is obtained,..., The cuff pressure change due to the pulse wave is sequentially obtained up to dPn. Then, based on Boyle Charles' law, dP1 to dPn are converted into blood vessel volume changes, and after obtaining the respective compliances, the blood vessel stiffness measuring device calculates the ratio of two predetermined compliances.

According to the present invention, by applying pressure from the outside of the blood vessel (applying cuff pressure), the blood vessel sclerosis degree is measured when the internal / external pressure difference of the blood vessel is near 0 (B). There is an effect that the index does not depend on the blood pressure value.

  The best mode for carrying out the invention is the following examples.

  FIG. 1 is a block diagram illustrating a vascular sclerosis measuring apparatus 100 that is Embodiment 1 of the present invention.

  The blood vessel sclerosis measuring device 100 integrates the cuff pressure differential value over a period from the substantially maximum peak value of the cuff pressure differential value to 0, and based on the integrated pressure value, the blood vessel is measured. It is an Example which evaluates the extensibility of.

  The blood vessel sclerosis measuring apparatus 100 includes a cuff 11 wound around the arm of a measurement subject, a pressurizing unit 12 that pressurizes the cuff 11 to a predetermined pressure necessary for blood pressure measurement, and a cuff pressurized by the pressurizing unit 12. 11 includes a slow speed exhausting means 13 for gradually exhausting the pressure in the pressure 11, a pressure transducer for detecting the pressure of the cuff 11, a pressure detecting means 14 for converting the pressure into an electrical signal (pulse) and outputting the pressure, and a pressure detecting means. 14, counts the electric signal (pulse) from 14 within a predetermined time, periodically repeats the above counting by the sampling signal, and A / D converts the sampling value, CPU 20, ROM 30, RAM 40, The operation unit 50, the display device 61, the printer 62, and the external terminal 63 are included.

  The cuff 11, the pressurizing means 12, the slow exhaust means 13, and the pressure detecting means 14 are connected by a flexible tube. Further, the pressurizing means 12, the forced exhaust means 13, the pressure detecting means 14, and the sampling means 15 are controlled by the CPU 20.

  The CPU 20 controls the entire hemodynamic measurement device 100 and functionally cooperates with a program stored in the ROM 30 to function as a pulse wave component extraction unit 21, a differential waveform formation unit 22, and the like. The peak detecting means 23, the integrating means 24, and the ratio calculating means 25 are realized.

  The pulse wave component extraction means 21 is a means for extracting the pulse wave component of the cuff pressure.

  The differential waveform forming means 22 calculates the primary differential value by time-differentiating the extracted pulse wave component to form a differential waveform.

  The peak detection means 23 obtains a substantially peak of the formed differential waveform.

  The integrating means 24 integrates the differential waveform from the time when the differential waveform is substantially peak until the value of the differential waveform becomes substantially zero, and sequentially obtains the cuff pressure changes dP0 to dPn.

  The ROM 30 is a memory in which a program of a flowchart shown in FIG. 8 described later is stored, the RAM 40 is a memory for storing calculation results of the CPU 20, and the operation means 50 has predetermined function keys and the like. is there.

  Next, the operation of the hemodynamic measurement device 100 will be described.

  FIG. 2 is a diagram showing a change in cuff pressure in the above embodiment.

  The cuff 11 is wrapped around the arm, wrist, finger, etc., and the pressure inside the cuff 11 is increased to a predetermined pressure by the pressurizing means 12, and then the linear exhausting means 13 at a rate of 3-5 mmHg / sec. The pulse wave amplitude component is superimposed on the cuff pressure in the process of this pressure reduction.

  When measuring hemodynamics with the hemodynamic measuring device 100, specifically, when the cuff 11 is wound around the arm of the measurement subject and the measurement start switch provided in the operation means 50 is turned on, it is necessary for blood pressure measurement. The pressurizing means 12 pressurizes the cuff 11 until it reaches a certain pressure, and after the pressurization is stopped, the air in the cuff 11 is gradually exhausted by the slow exhaust means 13, and the pressure displacement due to the pulse wave component is accompanied accordingly. Begins to be transmitted to the cuff.

  The pressure detection means 14 converts the cuff pressure into an electrical signal as a change in frequency, the sampling means 15 samples at regular intervals (for example, every 5 ms), and outputs a pulse according to the sampled cuff pressure. .

  FIG. 3 is a diagram illustrating a waveform of the pulse wave amplitude P and a differential waveform of the pulse wave amplitude P.

  FIG. 3A is a diagram showing a waveform of the pulse wave amplitude P, in which the horizontal axis indicates time and the vertical axis indicates the pulse wave amplitude P. FIG. 3 (2) is a diagram showing a differential waveform of the pulse wave amplitude P.

  FIG. 4 is a diagram illustrating a state in which the diameter of the blood vessel is decreased due to the cuff pressure.

  When the internal pressure of the blood vessel is Pb, the external pressure (cuff pressure) of the blood vessel is Pc, and the internal / external pressure difference Pt of the blood vessel is Pt = (Pb−Pc), the internal / external pressure difference Pt is Consider the process of increasing as Pc decreases.

  FIG. 5 is an explanatory diagram of the internal / external pressure difference Pt.

  FIG. 6 is a diagram showing a change in volume per unit length of a blood vessel with respect to an internal / external pressure difference.

  When the internal / external pressure difference Pt is negative, the blood vessel is crushed and the cross-sectional area of the blood vessel is almost zero. When the internal / external pressure difference Pt becomes slightly positive, the blood vessel rapidly expands the cross-sectional area, and the internal pressure is evenly applied, so that the cross-sectional shape of the blood vessel becomes substantially circular.

  Therefore, the cross-sectional area changes abruptly in the vicinity of the blood pressure difference Pt = 0. On the other hand, the blood vessel is an elastic body and has a property of expanding (extensibility) in accordance with the internal / external pressure difference Pt of the blood vessel. However, it has been found that when a blood vessel grows to a certain extent, its expansion is limited by an outer membrane having low extensibility.

  The extensibility in a region where the internal / external pressure difference Pt of the blood vessel is relatively low is represented by the characteristics of the media of the blood vessel. Conversely, in the region of a high pressure difference, the extensibility of the external membrane of the blood vessel is dominant.

  Next, how the cross-sectional area of the blood vessel changes as the cuff pressure decreases will be described with reference to FIG.

  [Step 1] This is a step in which the internal / external pressure difference Pt is a negative region (Pt <0), and the cross-sectional area of the blood vessel is almost 0 and does not change.

  [Step 2] The internal / external pressure difference Pt becomes slightly positive, the cross-sectional area of the blood vessel rapidly increases, and the time differential value of the cuff pressure reaches a peak (time t1).

  [Stage 3] The internal / external pressure difference Pt further increases, and the cross-sectional area of the blood vessel expands according to the extensibility of the media of the blood vessel. Compared with the state in the above-mentioned stage 2, since it decreases rapidly, the differential value of the cuff pressure also decreases.

  [Stage 4] The pressure is further increased, and the blood vessel hardly stretches due to the stress caused by the outer membrane of the blood vessel. Therefore, the differential value of the cuff pressure drops to 0 (time t2).

  Here, in FIG. 3 (2), the time when the differential value reaches its peak is t1, the time when the differential value becomes 0 is t2, and the differential value in the interval between time t1 and time t2 is shown. Let the integral value be dP. The integrated value dP is a result of the volume change dV caused by the expansion of the blood vessel caused by the internal / external pressure difference Pt, and the volume change dV caused by increasing the cuff pressure.

By the way, when the internal / external pressure difference Pt is 0 (when the blood vessel is collapsed), the capacity of the cuff is V, and the cuff pressure in this case is P, according to Boyle Charles' law,
P ・ V = k …… Formula (1)
(K is a constant). That is, according to Boyle Charles' law, if the temperature is constant, the product of the cuff capacity V and the cuff pressure P is constant.

  Here, when a slight cuff pressure change dP occurs due to pulsation, it is assumed that the volume V of the cuff causes a small volume change dV. Thus, when a slight cuff pressure change dP due to pulsation occurs, a cuff pressure (P + dP) after the slight cuff pressure change dP due to the pulsation and a slight cuff pressure change dP due to the pulsation occur. Subsequent cuff capacity (V + dV) is substituted into equation (1) above. By this substitution, the following equation (2) can be obtained.

(P + dP) · (V + dV) = k (2)
When this equation (2) is transformed,
V + dV = k / (P + dP)
And therefore
dV = {k / (P + dP)} − V
= {K- (P + dP) V} / (P + dP)
= (K−P · V−dP · V) / (P + dP) (3)
It is.

Here, according to the above equation (1),
Since P · V = k, the above equation (3) is
dV = (kP.V-dP.V) / (P + dP) = (k-dP.V) / (P + dP)
= −dP · V / (P + dP) (Formula 4)
become. Therefore, dV calculated from dP obtained by measurement is a numerical value depending on the cuff capacity V.

  FIG. 7 is a diagram illustrating a characteristic of the compliance C with respect to the internal / external pressure difference Pt in the first embodiment.

  The relationship between the internal / external pressure difference Pt and the compliance C (dV / dP) is qualitatively as shown in FIG. 7, that is, the compliance C reaches its maximum value near the internal / external pressure difference Pt = 0. When the internal / external pressure difference Pt increases from the internal / external pressure difference Pt = 0, the compliance C gradually decreases. However, in order to obtain the compliance C itself by measurement, it is necessary to accurately measure the cuff capacity, which is not easy.

  The relationship between the degree of hardening of the blood vessel and the compliance C is indicated by a dotted line in FIG. 7. The harder the blood vessel, the lower the maximum value of the compliance C (maximum compliance C0), and the characteristic curve of the compliance C with respect to the internal / external pressure difference Pt. Is known to draw a gentle curve.

  Here, the compliance C when the internal / external pressure difference Pt = 0 is the maximum compliance C0, and the compliance C when the internal / external pressure difference Pt is the predetermined internal / external pressure difference Pt1 is C1. The “compliance ratio CF” is defined as C1 / C0. That is, the compliance ratio CF = (C1 / C0). Since C1 <C0, 0 <CF <1. As is clear from FIG. 7, the compliance ratio CF increases as the degree of cure increases.

Here, when vascular volume change is dv and internal / external pressure difference is Pt, vascular compliance C is
C = dv / dPt
It is expressed.

Therefore,
C0 = dv0 / dPt
C1 = dv1 / dPt
And therefore
CF = C1 / C0 = dv1 / dv0
It is.

Since dv0 and dv1 have the same size and the same magnitude as the volume change of the cuff (the expansion of the blood vessel causes the cuff compression), if the corresponding cuff volume change is dv0 and dv1,
CF = −dV / −dV0 = dV1 / dV0 Equation (5)
It becomes.

  On the other hand, from the formula (4), CF can be substituted as follows.

Cf = {− dP1 · V1 / (P1 + dP1)} / {− dP0 · V0 / (P0 + dP0)}
Here, if P1 >> dP1 and P0 >> dP0,
CF = (dP1 / dP0). (P0 / P1) (6)
From Equation (6), it can be seen that the compliance ratio CF is an index that does not depend on the cuff capacity V.

  Since P and dP included in the right side of the expression (6) indicating the compliance ratio CF are the cuff pressure and the change data itself of the superimposed cuff pressure, respectively, by using the compliance ratio CF, Regardless of the cuff volume, the degree of vascular stiffness can be expressed. That is, since the cuff capacity is the thickness of the blood vessel and the blood pressure, the degree of sclerosis of the blood vessel can be known by using the compliance ratio CF regardless of the thickness of the blood vessel and the blood pressure.

  FIG. 8 is a flowchart showing an operation of actually measuring hemodynamics in the hemodynamic measuring device 100.

  FIG. 9 is a diagram illustrating the cuff pressure Pc that changes with time when the cuff pressure Pc is increased to a predetermined pressure Ps and then reduced.

  In the hemodynamic measurement device 100, when the cuff 11 is wound around the upper arm of the measurement subject and the power is turned on, the contents of the RAM 40 are initialized, and then the pressure of the cuff 11 is increased to a predetermined pressure Ps (S1). .

  Thereafter, the cuff 11 is gradually exhausted, that is, the pressure is reduced at a constant speed (S2).

  FIG. 10 (1) is a diagram in which one pulse wave is extracted from FIG. 9 (1), and FIG. 10 (2) is a diagram illustrating the pulse wave component after correcting the decompression component. 3) is a diagram showing a characteristic dP / dt obtained by differentiating the cuff pressure P with respect to time.

  In the exhaust process, the pulse pressure changes the cuff pressure, and the pulse wave component is superimposed on the cuff pressure. A pulse wave component is extracted by correcting the decompression component from the cuff pressure (S3). The extracted pulse wave component is stored in the RAM 40.

  Next, this pulse wave component is differentiated (S4). Based on the value stored in the RAM 40, a time differential signal of the sampling value is calculated.

  Further, the differential value dP / dt of the pressure is integrated between time t1 when the pulse wave component is the maximum value and time t2 when the pulse wave component subsequently becomes 0 (S5).

  Then, the process returns to S1. In this way, steps S1 to S5 are repeated, and when the pressure decreases to a predetermined cuff pressure (S5a), the process proceeds to S6.

  FIG. 11 is a diagram illustrating characteristics in which the cuff pressure changes dP1 to dPn are plotted on the time axis.

  Cuff pressure changes dP1 to dPn are plotted on the time axis (S6).

  A slight cuff pressure change dP is converted into a volume change dV (boiled charle), and an envelope is drawn (S7).

  FIG. 12 is a diagram showing a characteristic of a value dV / dPc obtained by differentiating the change in volume with respect to the cuff pressure Pc with respect to the cuff pressure.

  “P0-20” shown in FIG. 12 is a cuff pressure that is 20 mmHg lower than the cuff pressure P0.

  The volume change dV is differentiated by the cuff pressure Pc and plotted again (S8). The maximum value of the value dV / dPc obtained by differentiating the volume change with pressure is C0, and the cuff pressure when the value dV / dPc obtained by differentiating the volume change with pressure is the maximum value C0 is P0 (S9). .

  The dV / dPc at the cuff pressure lowered by about 20 mmHg from the cuff pressure P0 is defined as C1 (S10). Then, a compliance ratio CF = C1 / C0 is calculated (S11).

  When the blood pressure Pb is performing a constant pulsation, the internal / external pressure difference Pt increases according to the pressure reduction rate of the cuff pressure.

  The operation shown in the flowchart of FIG. 8 is an example of measurement when measurement is performed while reducing the cuff pressure.

  When measuring by increasing the cuff pressure, the cuff pressure is gradually increased, and the pulse components appearing in the meantime are extracted.

  When the cuff pressure is measured at a constant pressure, the blood pressure Pb actually varies physiologically, so the data varies.

  FIG. 13 is a diagram showing the passage of time and the change in the cuff pressure Pc when the cuff pressure is measured while being increased.

  For example, as shown in FIG. 13 (3), if the pressure reduction is repeated stepwise and the measurement time is increased, the pulse wave number at each pressure increases, and the accuracy increases by taking the average value. Even if the pressure increase / decrease rate is lowered, the same effect is obtained. That is, if the speed is lowered, the measurement time becomes longer, and the number of pulses appearing during the measurement increases accordingly, so that the measurement accuracy increases.

  According to the above-described embodiment, by applying pressure from the outside of the blood vessel (applying cuff pressure), the blood vessel sclerosis degree is measured when the difference between the internal and external pressures of the blood vessel is approximately zero. It is an indicator that does not depend on.

  FIG. 14 is a diagram showing the internal / external pressure difference-volume of a blood vessel.

  B shown in FIG. 14 is a region where the characteristics of the media are dominant, and A and A ′ shown in FIG. 14 are regions including both the properties of the media and the outer membrane. In recent medicine, the properties of the media are becoming more important.

  FIG. 15 is a diagram illustrating a specific example of displaying measurement data in the first embodiment.

  The display example shown in FIG. 15 is a diagram showing the cuff pressure on the horizontal axis and the compliance C on the vertical axis. Since the maximum compliance C0 is 1 and the compliance C1 is 0.84, the compliance CF value (C0 / C1) is 0.84.

  If the display device 61 displays the display example shown in FIG. 15, the display device 61 is an example of a calculation result display means for displaying the compliance ratio calculated by the ratio calculation means.

  FIG. 16 is a diagram illustrating a specific example of external output and a specific example of accumulation in an internal memory in the first embodiment.

  The CPU 20 is an example of outputting the compliance ratio CF to the personal computer PC and the memory card MC. In other words, the CPU 20 is an example of calculation result output means for outputting the compliance ratio CF calculated by the ratio calculation means to the outside.

  FIG. 17 is a diagram illustrating a specific example in which the difference between the compliance ratio and the average value of clinical data is displayed in the first embodiment.

  Further, according to the above-described embodiment, it is possible to evaluate the characteristic of the vascular media that is important in evaluating the extensibility of blood vessels.

  Furthermore, according to the above embodiment, since the evaluation method uses the compliance ratio, it is possible to measure the degree of vascular stiffness that does not depend on the cuff capacity or the thickness of the blood vessel.

  According to the above embodiment, since the blood vessel sclerosis measuring device can be manufactured using the hardware of the conventional oscillometric sphygmomanometer as it is, the blood vessel sclerosis measuring device can be manufactured very inexpensively. Can do.

  Moreover, according to the said Example, when a test subject measures the hardening degree of a blood vessel, it can measure a blood vessel hardening degree simultaneously with a blood pressure measurement, without preparing specially.

Further, in the above-described embodiment, the blood pressure may be measured simultaneously with the measurement of the degree of vascular sclerosis, and the data for several beats may be averaged. By doing so, errors due to physiological fluctuations of pulsation can be reduced.

1 is a block diagram illustrating a blood vessel sclerosis measuring apparatus 100 that is Embodiment 1 of the present invention. FIG. It is a figure which shows the change of the cuff pressure in the said Example. It is a figure which shows the waveform of the pulse wave amplitude P, and the differential waveform of the pulse wave amplitude P. It is a figure which shows the state in which the diameter of the blood vessel is reducing by the cuff pressure. It is explanatory drawing of the internal / external pressure difference Pt. It is a figure which shows the change of the volume per unit length of the blood vessel with respect to an internal / external pressure difference. In Example 1, it is a figure which shows the characteristic of the compliance C with respect to the internal / external pressure difference Pt. 5 is a flowchart showing an operation of actually measuring hemodynamics in the hemodynamic measuring device 100. It is a figure which shows the cuff pressure Pc which changes with time, when it pressurizes after reducing the cuff pressure Pc to the predetermined pressure Ps. FIG. 10 is a diagram showing a characteristic dP / dt obtained by time-differentiating one pulse wave component extracted from FIG. 9, a pulse wave component after correcting the cuff decompression component from the pulse wave component, and the cuff pressure P; It is a figure which shows the characteristic which plotted the change part dP1-dPn of the cuff pressure on the time-axis. It is a figure which shows the characteristic of the value dV / dPc which differentiated cuff pressure Pc versus volume change with pressure. It is a figure which shows the passage of time and the change of cuff pressure Pc in the case where cuff pressure is increased and measured. The conventional example is that the measurement value changes depending on the blood pressure (difference in the slopes of A and A '). It is a figure which shows that an Example evaluates the characteristic of a film more. In Example 1, it is a figure which shows the specific example which displays measurement data. In Example 1, it is a figure which shows the specific example output externally, and the specific example accumulate | stored in an internal memory. In Example 1, it is a figure which shows the specific example which displays the difference of the ratio of a compliance, and its standard value.

Explanation of symbols

100 ... hemodynamic measuring device,
11 ... cuff,
20 ... CPU,
21 ... Pulse wave component extraction means,
22 ... Differential waveform forming means,
23 ... Peak detection means,
24. First integrating means,
25. Second integration means,
26: Ratio calculation means,
30 ... ROM,
40 ... RAM,
50 ... operation means,
61. Display means,
62 ... Printer,
63 ... external terminal,
Pb ... Inner blood pressure,
Pc ... cuff pressure,
Pt: internal and external pressure difference of blood vessel (Pb-Pc),
dP: Change in cuff pressure,
dV: Volume change,
P0: Internal / external pressure difference at maximum compliance C0,
C0: Maximum compliance,
C1: Compliance (dV / dPt) at the internal / external pressure difference lowered by about 20 mmHg from the cuff pressure P0,
CF: Compliance ratio (C1 / C0).

Claims (7)

A pulse wave component extraction means for extracting a pulse wave component of the cuff pressure;
Differential waveform forming means for calculating a primary differential value by time differentiation of the extracted pulse wave component and forming a differential waveform;
Peak detecting means for obtaining a substantially peak of the formed differential waveform;
The differential waveform is integrated from the time when the differential waveform is substantially peak until the value of the differential waveform becomes substantially zero, and a change amount dP1 of the first cuff pressure due to the first pulse wave is obtained. Similarly, integration means for sequentially obtaining the second to nth cuff pressure changes dP2 to dPn due to the second to nth pulse waves;
Means for plotting the integrated values dP1 to dPn on an axis and storing them in a storage device;
A means for converting the change dP of the cuff pressure into a volume change dV based on Boyle-Charles' law, drawing an envelope and storing it in a storage device;
Means for differentiating the volume change dV with the cuff pressure Pc, re-plotting, and storing in the storage device;
means for calculating a compliance by calculating dV / dPc, and storing a maximum compliance C0 which is the maximum value of the determined compliance in a storage device;
Means for calculating and storing (dV / dPc) = compliance C1 at a cuff pressure that is approximately 20 mmHg lower than the cuff pressure p0, with the cuff pressure at the maximum compliance C0 being P0;
(Compliance C1 / Maximum Compliance C0) = Calculation means for calculating a compliance ratio CF and storing it in a storage device;
An apparatus for measuring the degree of vascular stiffness, comprising: In claim 1,
The pulse wave component extracting means is means for extracting the pulse wave component of the cuff pressure for each pulse, while increasing, decreasing, or as a constant value of the cuff pressure. measuring device. In claim 1,
An apparatus for measuring the degree of vascular sclerosis, which measures blood pressure at the same time as measuring the degree of vascular sclerosis, and averages data of several beats. In claim 1,
Display means for displaying the calculated feature value, output means for outputting the calculated feature value to the outside, and storing the calculated feature value in a memory provided in the vascular stiffness measuring apparatus An apparatus for measuring a degree of vascular sclerosis comprising at least one of storage control means. In claim 1,
Storage means for storing a table containing standard values of the compliance ratio;
A computing means for computing a difference between the obtained compliance ratio and a standard value of the compliance ratio;
An apparatus for measuring the degree of vascular stiffness, comprising: In claim 5,
Calculation result display means for displaying the compliance ratio calculated by the ratio calculation means, calculation result output means for outputting the compliance ratio calculated by the ratio calculation means to the outside, and storage of the compliance ratio calculated by the ratio calculation means An apparatus for measuring a degree of vascular sclerosis, comprising at least one means among calculation result storage means. A pulse wave component extraction means for extracting a pulse wave component of the cuff pressure;
Differential waveform forming means for calculating a primary differential value by time differentiation of the extracted pulse wave component and forming a differential waveform;
Peak detecting means for obtaining a substantially peak of the formed differential waveform;
The differential waveform from the time when the differential waveform is substantially peak until the value of the differential waveform becomes almost zero is integrated to obtain the first cuff pressure change dP1. integration means for sequentially obtaining the changes dP2 to dPn of the cuff pressure of n;
Means for plotting the integrated values dP1 to dPn on the axis, calculating the cuff pressure Pc, and storing the calculated value in a storage device;
Means for converting the differential value dP to a volume change dV based on Boyle-Charles' law, drawing an envelope and storing it in a storage device;
Means for differentiating the volume change dV with the cuff pressure Pc, re-plotting, and storing in the storage device;
means for calculating a compliance by calculating dV / dPc, and storing a maximum compliance C0 which is the maximum value of the determined compliance in a storage device;
Means for calculating and storing (dV / dPc) = compliance C1 at an internal / external pressure difference that is approximately 20 mmHg lower than the cuff pressure P0, where the cuff pressure at the maximum compliance C0 is P0;
(Compliance C1 / Maximum Compliance C0) = Calculation means for calculating a compliance ratio CF and storing it in a storage device;
Blood pressure determination means for determining that the cuff pressure at which the compliance value is maximized is a maximum blood pressure value;
A blood pressure measurement device comprising:

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