JP5518554B2 - Vascular hardness evaluation system and vascular hardness index calculation method - Google Patents

Description

  The present invention relates to a blood vessel hardness evaluation system and a blood vessel hardness evaluation method for evaluating blood vessel hardness.

  Management of blood circulation is important in managing health. Blood pressure is measured as a risk factor in blood circulation, and a sphygmomanometer using an oscillometric method is used for blood pressure measurement.

  In the oscillometric method, an arm band (cuff) containing an air bag is wrapped around a measurement site of a living body to be measured, the cuff is pressurized to temporarily stop blood flow, and then the pressure is reduced. Is measuring. In the cuff decompression process, when the blood flow resumes, the blood vessel volume changes (stretches and contracts) with the pulsation of the blood vessel. Therefore, the change in the blood vessel volume can be measured as a change in the internal pressure of the measurement cuff, and a predetermined measurement interval. By measuring the internal pressure change of the cuff, the blood pressure at each measurement time is calculated.

  In addition, the hardness of blood vessels is evaluated as another risk factor. For example, Patent Document 1 discloses a device that determines the degree of arteriosclerosis by examining the speed of propagation of a pulse wave ejected from the heart (hereinafter referred to as PWV: pulse wave velocity). PWV is used as an index for determining the degree of arteriosclerosis using the fact that the pulse wave velocity increases as arteriosclerosis progresses.

  Such PWV is equipped with a cuff or the like in at least two places such as the upper arm and the lower limb, and simultaneously measures the pulse wave, so that the difference in the appearance time of each pulse wave and the length of the artery between the two points wearing the cuff or the like. And is calculated using The value of PWV varies depending on the measurement site. For example, the pulse wave transmission speed between the upper arm and the lower leg artery (baPWV) where the measurement site is the upper arm and the ankle, and the pulse wave transmission speed between the carotid artery and the femoral artery where the carotid artery and the femoral artery are located. (CfPWV).

  However, it is cumbersome to measure PWV by attaching cuffs to two or more places in this way. Therefore, it has been proposed to evaluate the hardness of blood vessels from blood pressure measurement data.

  For example, Patent Document 2 discloses deriving a circulatory dynamic index such as the hardness of a blood vessel by matching a pattern portion including an amplitude envelope of blood pressure measurement data with a polygonal outline pattern. .

  Patent Document 3 discloses that the hardness of the artery wall is evaluated based on the amplitude of the pulse wave detected by the cuff.

  Further, in Patent Document 4, the central side and the terminal side of the measurement site are compressed, the time difference between the ejection wave and the reflected wave is calculated from the change in the internal pressure on the central side, and the degree of arteriosclerosis is determined. It is disclosed that it is used as an index.

JP 2000-316821 A JP 2005-323853 A JP 2008-228934 A JP 2009-119067 A

  However, Patent Document 2 compares blood pressure measurement data with a polygonal pattern, and Patent Document 3 also expresses the relationship between the internal / external pressure difference of the blood vessel and the blood vessel diameter as a pressure characteristic curve. 4, the time difference between the ejection wave and the reflected wave is calculated, and none of them evaluates the blood vessel hardness from the fluctuation of blood pressure at each measurement time point.

  In view of the above problems, an object of the present invention is to provide a blood vessel hardness evaluation system and a blood vessel hardness evaluation method capable of appropriately evaluating the hardness of a blood vessel.

  In order to achieve the above object, the present invention provides a temperature adjusting means for changing the environmental temperature of a blood vessel to a predetermined temperature, a blood pressure measuring means for measuring the blood pressure over time by pressurizing the blood vessel and then reducing the blood pressure, and the blood pressure A blood vessel hardness evaluation system comprising: calculation means for calculating an index of blood vessel hardness based on an amount of fluctuation from a measurement time immediately before each measurement time point in the blood pressure measured by the measurement means.

  According to the present invention, in the vascular hardness evaluation system having the above-described configuration, the blood pressure measurement unit measures the blood pressure over time by repeatedly applying and depressurizing the blood vessel at predetermined intervals.

  According to the present invention, in the vascular hardness evaluation system having the above-described configuration, the temperature adjusting unit raises the environmental temperature to the predetermined temperature.

  According to the present invention, in the vascular stiffness evaluation system having the above-described configuration, the calculation unit calculates the difference in blood pressure with respect to the immediately preceding measurement time point sequentially for each measurement time point, and the absolute value of the calculated difference is calculated. The index is calculated based on the sum of values.

  In the vascular hardness evaluation system having the above-described configuration, the calculation unit may include a first number of times that the difference has changed from 0 or more to less than 0 at the measurement time point as compared to the previous measurement time point; The index is calculated based on the second number of times that has changed from less than 0 to 0 or more.

  In the vascular hardness evaluation system having the above-described configuration, the temperature adjustment unit maintains the predetermined temperature at a constant temperature, and the blood pressure is measured at the environmental temperature maintained at the constant temperature. It is characterized by being measured by.

  Further, the present invention is to measure the blood pressure over time by pressurizing and depressurizing the blood vessel at the ambient temperature of the blood vessel changed to a predetermined temperature, and from the measurement time immediately before each measurement time point in the measured blood pressure. This is a blood vessel hardness evaluation method for calculating an index of blood vessel hardness based on the amount of fluctuation.

  Further, the present invention is characterized in that in the blood vessel hardness evaluation method having the above-described configuration, the blood pressure is measured over time by repeatedly applying and depressurizing the blood vessel at predetermined intervals.

  Further, the present invention is characterized in that, in the blood vessel hardness evaluation method configured as described above, the environmental temperature is raised to the predetermined temperature.

  In the vascular hardness evaluation method having the above-described configuration, the present invention calculates a difference in blood pressure with respect to the immediately preceding measurement time point sequentially for each measurement time point, and is based on a sum of absolute values of the calculated difference values. And calculating the index.

  In the vascular hardness evaluation method having the above-described configuration, the first time that the difference has changed from 0 or more to less than 0 compared to the immediately previous measurement time, and less than 0 to 0 or more in the measurement time point. The index is calculated on the basis of the second number of times changed.

  Further, the present invention is characterized in that, in the blood vessel hardness evaluation method configured as described above, the predetermined temperature is maintained at a constant temperature, and the blood pressure is measured under the environmental temperature maintained at the constant temperature.

  According to the first configuration of the present invention, the temperature adjusting means for raising the environmental temperature of the blood vessel to a predetermined temperature, the blood pressure measuring means for measuring the blood pressure over time by pressurizing the blood vessel and reducing the blood pressure, and the blood pressure measurement A change in environmental temperature by providing a blood vessel hardness evaluation system comprising: a calculation means for calculating a blood vessel hardness index based on a fluctuation amount from a measurement time immediately before each measurement time point in the blood pressure measured by the means. Measurement of blood pressure can begin with the start. As a result, since the blood vessel hardness index can be calculated by capturing a transient state in which the inner diameter of the blood vessel changes from the start of blood pressure measurement, it is possible to appropriately evaluate the blood vessel hardness.

  According to the second configuration of the present invention, in the vascular hardness evaluation system according to the first configuration, the blood pressure measurement unit repeatedly measures the blood pressure over time by repeating the pressurization and decompression of the blood vessel at predetermined intervals. Thus, the blood vessel hardness can be more appropriately evaluated.

  Further, according to the third configuration of the present invention, in the vascular hardness evaluation system of the first or second configuration, the temperature adjusting means raises a transient state in which the blood vessel expands by raising the environmental temperature to a predetermined temperature. Since it is possible to calculate the blood vessel hardness index, it is possible to more appropriately evaluate the blood vessel hardness.

  Further, according to the fourth configuration of the present invention, in the vascular hardness evaluation system having any one of the first to third configurations, the calculation means sequentially performs the measurement between the immediately preceding measurement time points for each measurement time point. By calculating the blood pressure difference and calculating the index based on the sum of the absolute values of the calculated differences, the magnitude of the blood vessel vibration can be grasped as a numerical value, so that the blood vessel hardness can be evaluated in more detail. it can.

  Further, according to the fifth configuration of the present invention, in the vascular hardness system of the fourth configuration, the calculating means changes the difference from 0 or more to less than 0 at the measurement time as compared to the previous measurement time. By calculating an index based on the first number of times and the second number of times that has changed from less than 0 to 0 or more, the frequency of blood vessel vibration can be grasped as a numerical value. Can be evaluated.

  According to the sixth configuration of the present invention, in the vascular hardness evaluation system according to any one of the first to fifth configurations, the temperature adjusting means maintains the predetermined temperature at a constant temperature and maintains the constant temperature. By measuring the blood pressure with the blood pressure measurement means at the ambient temperature, the influence of the variation in the environmental temperature on the blood vessel hardness evaluation can be avoided.

  Further, according to the seventh configuration of the present invention, the blood pressure is measured over time by pressurizing the blood vessel at the ambient temperature of the blood vessel changed to a predetermined temperature, and the blood pressure is measured over time. By using the blood vessel hardness evaluation method that calculates the blood vessel hardness index based on the blood pressure fluctuation amount from the measurement time immediately before the measurement of blood pressure, the measurement of blood pressure can be started at the same time as the change in environmental temperature starts. As a result, since the blood vessel hardness index can be calculated by capturing a transient state in which the inner diameter of the blood vessel changes from the start of blood pressure measurement, the blood vessel hardness can be more appropriately evaluated.

  Further, according to the eighth configuration of the present invention, in the vascular hardness evaluation method of the seventh configuration, the vascular stiffness is measured by repeatedly measuring the blood pressure over time by repeatedly applying and depressurizing the blood vessel at predetermined intervals. Can be evaluated more appropriately.

  According to the ninth configuration of the present invention, in the blood vessel hardness evaluation method according to the seventh or eighth configuration, the blood pressure is measured at the same time when the environmental temperature starts to increase by increasing the environmental temperature to a predetermined temperature. Can start. Thereby, since the blood vessel hardness index can be calculated by capturing a transient state in which the blood vessel expands from the start of blood pressure measurement, the blood vessel hardness can be more appropriately evaluated.

  Further, according to the tenth configuration of the present invention, in the vascular hardness evaluation method according to any one of the seventh to ninth configurations, a difference from the blood pressure at the immediately previous measurement time is calculated sequentially for each measurement time. By calculating the index based on the sum of the absolute values of the calculated differences, the magnitude of the blood vessel vibration can be grasped as a numerical value, so that the blood vessel hardness can be evaluated in more detail.

  According to the eleventh configuration of the present invention, in the vascular hardness evaluation method according to the tenth configuration, the first change in the difference from 0 or more to less than 0 at the measurement time as compared to the immediately previous measurement time. By calculating an index based on the number of times and the second number that has changed from less than 0 to 0 or more, the frequency of blood vessel vibration can be grasped as a numerical value, so that blood vessel hardness can be evaluated in more detail. Can do.

  According to the twelfth configuration of the present invention, in the blood vessel hardness evaluation method according to any one of the seventh to eleventh configurations, the environmental temperature maintained at a constant temperature by maintaining a predetermined temperature at a constant temperature. By measuring the blood pressure below, it is possible to avoid the influence of the variation in environmental temperature on the blood vessel hardness evaluation.

Schematic which shows the structure of the vascular hardness evaluation system which concerns on one Embodiment of this invention. A diagram schematically showing the relationship between time and blood pressure A diagram schematically showing the relationship between time and blood pressure A diagram schematically showing the relationship between time and blood pressure FIG. 5A is a diagram schematically showing an example of a temperature change of a heat source of the temperature regulator, FIG. 5A is a diagram showing a step change, and FIG. 5B is a diagram showing an exponential change. FIG. 5C shows a rectangular change. Sample No. A graph showing the relationship between time and maximum blood pressure in 1 Sample No. The graph which shows the relationship between the time in 1 and the minimum blood pressure Sample No. Graph showing the relationship between time and maximum blood pressure in 2 Sample No. Graph showing the relationship between time and minimum blood pressure in 2 Sample No. Graph showing the relationship between time and maximum blood pressure in 3 Sample No. Graph showing the relationship between time and minimum blood pressure in 3 Sample No. 1-No. 3 is a graph showing the relationship between the number of vibrations N of the maximum blood pressure and the ratio R for 3 Sample No. 1-No. 3 is a graph showing the relationship between the number of vibrations N of the minimum blood pressure and the ratio R for 3 Sample No. Graph showing the relationship between time and maximum blood pressure in 4 Sample No. Graph showing the relationship between time and minimum blood pressure in 4 Sample No. 3 and no. 4 is a graph showing the relationship between the number N of vibrations of maximum blood pressure and the ratio R Sample No. 3 and no. 4 is a graph showing the relationship between the number of vibrations N of the minimum blood pressure and the ratio R for 4

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing a configuration of a vascular hardness evaluation system according to an embodiment of the present invention.

  As shown in FIG. 1, the vascular hardness evaluation system 1 includes a sphygmomanometer (blood pressure measuring unit) 2, a storage unit 7, a calculating unit (calculating unit) 8, a display unit 9, and a temperature regulator (temperature adjusting unit) 10. The blood vessel hardness index described later can be calculated. Here, the blood vessel hardness index refers to a numerical value that can be used to evaluate the degree of blood vessel hardness, in other words, the degree of blood vessel softness. The ambient temperature of the blood vessel is adjusted by the temperature regulator 10. Here, the environmental temperature of the blood vessel refers to a temperature that can affect the inner diameter of the blood vessel, such as the temperature around the blood pressure measurement site and the temperature in the body surrounding the blood vessel, and may be simply referred to as the environmental temperature hereinafter.

  The sphygmomanometer 2 includes a cuff 3, a pump 4, a pressure sensor 5, and a control unit 6, and measures the blood pressure of the measurement subject by an oscillometric method.

  The cuff 3 is wound around a measurement site such as the upper arm of the measurement subject. The pump 4 pressurizes this to a preset target pressure by sending air into the cuff 3, and depressurizes it at a preset speed by drawing air. The pressure sensor 5 measures the internal pressure of the cuff 3 at a predetermined measurement interval and at a measurement time (a time from the start of measurement to the end of measurement). The internal pressure data measured at each measurement time is transmitted to the control unit 6.

  The control unit 6 includes a RAM, a ROM, a CPU, and the like. After the cuff 3 is pressurized to the target pressure by the pump 4, the pressure is reduced at a preset pressure reduction speed, and this is repeated by the pressure sensor 5. When the internal pressure of the cuff 3 is measured at a preset measurement interval and measurement time and the internal pressure data is received from the pressure sensor 5, the maximum blood pressure and the minimum blood pressure at each measurement time are calculated.

  The control unit 6 stores parameters such as the target pressure and pressure reduction speed of the cuff 3 by the pump 4, the measurement interval and measurement time by the pressure sensor 5, and the like. Further, the control unit 6 transmits the calculation result to the calculation unit 8 and the display unit 9 as temporal changes (blood pressure measurement data) of the maximum blood pressure and the minimum blood pressure.

  In addition, the measurement site | part by the cuff 3 is not specifically limited, If blood pressure can be measured by pressing a blood vessel (artery), it can be wound around the measurement site in the body such as the extremity of the person being measured. In addition, it may be wound around one place in the body of the measurement subject, but it can also be wound around a plurality of places, thereby making it possible to evaluate the blood vessel hardness at a plurality of measurement sites.

  Further, the target pressure at the time of pressurizing the cuff 3 and the speed at the time of depressurization are not particularly limited as long as an index of blood vessel hardness described later can be calculated. Can be set as appropriate. Further, the measurement interval and measurement time by the pressure sensor 5 are not particularly limited as long as a blood vessel hardness index, which will be described later, can be calculated. It can be set appropriately. Moreover, the control part 6 can also calculate average blood pressure, a pulse, etc. other than the temporal change of the maximum blood pressure and the minimum blood pressure.

  The storage unit 7 is, for example, a ROM and a RAM, and the blood vessel hardness is determined from the difference between the set temperature of the temperature regulator 10, the temperature change (here, increase) parameter, and the measurement time immediately before the blood pressure measurement data at each measurement time. Parameters for calculating the index are stored. Further, blood pressure measurement data measured by the sphygmomanometer 2 and calculated indices can be stored.

  The calculation unit 8 is, for example, a CPU, and has a function of analyzing blood pressure measurement data measured by the sphygmomanometer 2 by reading parameters stored in the storage unit 7 and calculating an index of blood vessel hardness. ing. That is, a function for calculating the difference (variation amount) between the blood pressure at each measurement time of the blood pressure measurement data and the blood pressure at the previous measurement time, a function for calculating the sum (addition value) of the absolute values of the calculated differences, It has a function of calculating the ratio (index) of the added value to the blood pressure at the start of measurement.

  Further, the calculation unit 8 calculates the number of times the difference has changed from 0 or more to less than 0 compared to the previous measurement time (first number), and the number of times the difference has changed from less than 0 to 0 or more (second number). The function of calculating (counting), the function of calculating the larger of these calculated times as the number of vibrations (index), the function of storing the calculated difference or index in the storage unit 7, the blood pressure measurement data, the ratio And a function of displaying the number of vibrations on the display unit 9.

  The storage unit 7 and the calculation unit 8 can be provided in a computer or the like separately from the sphygmomanometer 2, but can also be integrated with the control unit 6 in the sphygmomanometer 2. In such a case, for example, a parameter for calculating a blood vessel hardness index is stored in the control unit 6 together with the above-described blood pressure measurement parameter, and the control unit 6 measures the blood pressure based on the internal pressure data obtained from the pressure sensor 5. In addition to calculating data, an index of vascular hardness can be calculated.

  The display unit 9 has a start button for starting blood pressure measurement by the sphygmomanometer 2 and analysis by the calculation unit 8. The display unit 9 displays blood pressure measurement data measured by the sphygmomanometer 2 and an index of blood vessel hardness such as the ratio and the number of vibrations calculated by the calculation unit 8.

  The temperature regulator 10 can adjust, for example, the temperature of the blood pressure measurement chamber and the temperature of the standby chamber adjacent to the blood pressure measurement chamber to a constant temperature, and can maintain the temperature at the constant temperature. For example, the temperature of the blood pressure measurement chamber can be set higher than the temperature of the standby chamber. Thereby, when the person to be measured moves from the waiting room having a low environmental temperature to the blood pressure measuring room having a high environmental temperature, the blood vessel starts to expand from the moment of movement. Details of the temperature adjustment will be described later.

  Next, calculation of the blood vessel hardness index will be described. 2, 3 and 4 are diagrams schematically showing the relationship between time and blood pressure. As described above, when the person to be measured moves from the waiting room to the blood pressure measurement room and the blood pressure of the person to be measured is repeatedly measured using the sphygmomanometer 2, with the passage of time t as shown in FIG. The blood pressure P attenuates with amplitude (increase / decrease) up and down. After the cuff 3 is decompressed, when blood flows through the blood vessel, the blood vessel volume (cross-sectional area) approaches a steady state while repeatedly expanding and contracting, so both the maximum blood pressure and the minimum blood pressure vibrate with time (over time). It attenuates while approaching the steady state.

  That is, as shown in FIG. 2, the fluctuation of blood pressure P with respect to time t (temporal change in blood pressure measurement data) generally shows a damped oscillation type. Further, the blood vessel volume is less likely to expand and contract as the blood vessel is harder, and more easily expands and contracts as the blood vessel is softer. Therefore, for example, the magnitude of the amplitude of the damped vibration and the frequency of the vibration can indicate the magnitude and frequency of the vibration of the blood vessel. The softer the blood vessel, the larger the amplitude of the damped vibration and the greater the frequency of vibration. The harder the blood vessel, the smaller the amplitude of the damped vibration and the lower the frequency of vibration.

  Further, the higher the environmental temperature around the blood pressure measurement site, the softer the blood vessel and the larger the inner diameter of the blood vessel, and the lower the environmental temperature, the harder the blood vessel and the smaller the inner diameter of the blood vessel. Therefore, in the transient state where the degree to which the blood vessel expands and contracts changes, that is, in the process in which the ease of vibration of the blood vessel changes, by starting the blood pressure measurement at the same time as raising or lowering the environmental temperature. It becomes possible to grasp the amplitude and frequency of vibration.

  Further, when the environmental temperature rises, the blood vessel tends to expand and contract, and when it is maintained at a predetermined temperature, it finally becomes a steady state. Therefore, by starting the blood pressure measurement at the same time as increasing the environmental temperature, the amplitude and frequency of the vibration of the blood vessel is reduced in a transient state where the blood vessel is likely to expand and contract, that is, the blood vessel is likely to vibrate. It becomes possible to grasp. This makes it easy to calculate the amplitude and frequency.

  Therefore, by changing the environmental temperature and starting blood pressure measurement, analyzing the obtained blood pressure measurement data, calculating the magnitude of the blood pressure measurement data and the frequency of vibration as an index of blood vessel hardness, It becomes possible to evaluate vascular hardness. It is also possible to evaluate blood vessel hardness more appropriately by raising the environmental temperature and starting blood pressure measurement, and calculating the amplitude and vibration frequency of the blood pressure measurement data as an indicator of blood vessel hardness. It becomes.

Examples of the analysis of blood pressure measurement data include a method of calculating the magnitude of the attenuation vibration and the vibration frequency as follows. As shown in FIG. 2, it is assumed that blood pressures P ₀ , P ₁ , P ₂ , P ₃ , and P ₄ are obtained as blood pressure measurement data as time passes. At this time, the difference (variation amount) Ps _i with respect to the immediately preceding blood pressure at each measurement time point is calculated as Ps _i = P _i −P _i−1 (where i is an integer of 1 or more). That is, Ps ₁ = P ₁ -P ₀ , Ps ₂ = P ₂ -P ₁ , Ps ₃ = P ₃ -P ₂ , Ps ₄ = P ₄ -P ₃ .

The sum of absolute values of these four differences Ps _{1 to} Ps ₄ is set as an added value A, and after calculating by A = | Ps ₁ | + | Ps ₂ | + | Ps ₃ | + | Ps ₄ | by dividing the pressure P ₀ of the measurement start time, the ratio (index) R for P ₀ of a, by R = a / P _0, is calculated. Since the ratio R represents the magnitude of the amplitude of the damped vibration, it can be evaluated that the smaller the ratio R is, the harder the blood vessel is, and the larger the ratio R is, the softer the blood vessel is.

The change in the difference Ps ₁ ~Ps _4, compared with the measurement time just before, that is, the a Ps ₂ Ps _1, Ps ₃ and Ps _2, Ps ₄ compared to Ps _3, below 0 from 0 or more The number of times (first number) N1 and the number of times (second number) N2 changed from less than 0 to 0 or more are calculated. The larger numerical value of N1 and N2 is calculated as the vibration frequency (index) N.

  Since the vibration frequency N represents the frequency of vibration in the damped vibration, it can be evaluated that the smaller the vibration frequency N is, the harder the blood vessel is, and the larger the vibration frequency N is, the softer the blood vessel. If the vibration frequency N is the same, as described above, it can be evaluated that the blood vessel is harder as the ratio R is smaller, and the blood vessel is softer as the ratio R is larger.

  The sphygmomanometer 2 can obtain a temporal change in the maximum blood pressure and a temporal change in the minimum blood pressure as blood pressure measurement data, but any data may be used and is not particularly limited. . Whether one of the maximum blood pressure and the minimum blood pressure data is used or whether both data are used can be appropriately set by a preliminary experiment or the like. In addition, as described above, after the cuff 3 is decompressed, the cuff 3 is pressurized again and blood pressure measurement is repeated, and the ratio R and the vibration frequency N are calculated from the blood pressure measurement data obtained by each pressurization and decompression. it can.

  Further, by calculating the ratio R and the number of vibrations N for each blood pressure measurement data obtained by one measurement with the sphygmomanometer 2, the ratio R and the number of vibrations N can be relatively compared. Thereby, it is possible to evaluate relative vascular hardness between the ratio R and the number of vibrations N calculated from one blood pressure measurement data and the ratio R and the number of vibrations N calculated from other blood pressure measurement data. It becomes.

  Further, for example, the measurement of the above-mentioned brachial-crus artery pulse wave velocity baPWV (cm / s) and the blood pressure measurement with the sphygmomanometer 2 are performed on the measurement subject, and the obtained baPWV and the ratio R and By accumulating the data of the vibration frequency N, the correlation between baPWV, the ratio R, and the vibration frequency N can be examined. Thereby, it becomes possible to directly evaluate whether the hardness is higher than the average blood vessel hardness of a healthy person using the ratio R and the vibration frequency N.

  In addition, for example, once baPWV, the ratio R, and the vibration frequency N are measured for the same person to be measured, thereafter, only the blood pressure measurement data is measured, and the ratio based on the blood pressure measurement data is measured. By observing the progress of R and the number of vibrations N, it is also possible to examine changes in vascular hardness.

In the above description, the blood pressures P ₀ , P ₁ , P ₂ , P ₃ , and P ₄ are used as the actual measurement values. Instead of using the actual measurement values, a damped oscillation type approximate curve is calculated from the blood pressure measurement data. Then, the ratio R and the number of vibrations N can be calculated using the value and the extreme value at t = 0 of the approximate curve.

For example, referring to FIG. 2, a curve representing the relationship between time t and pressure P corresponds to an approximate curve, and P ₀ corresponds to a value at t = 0. P ₁ , P ₂ , P ₃ , and P ₄ correspond to the extreme values of the approximate curve. Among P _{1 to} P ₄ , P ₂ and P ₄ are maximum values, and P ₁ and P ₃ are minimum values. Corresponds to the value. Then, the difference Ps _i can be calculated from P _{0 to} P ₄ calculated in this way, as described above.

In the above description, P ₀ , P ₁ , P ₂ , P ₃ , and P ₄ indicate the fluctuation (vibration) of blood pressure measurement data with respect to the time axis (ie, blood pressure = 0), and the time axis is the center. The ratio R and the vibration frequency N were calculated from the blood pressure fluctuation. However, for example, as shown in FIG. 3, the difference Δ between the values when t = 0 with respect to a preset blood pressure Pb (a straight line parallel to the time axis).
P _0, the difference [Delta] P ₁ of each extremum on blood pressure Pb, ΔP _2, ΔP _3, and calculates the [Delta] P _4, the difference DerutaPs _i from these _{ΔP 0 ~ΔP 4, ΔPs i =} ΔP i -ΔP i-1 ( However, the ratio R and the number of vibrations N can also be calculated by calculating i in this expression by i).

  On the other hand, due to the individual difference, some blood pressure of the measurement subject is hardly contracted or expanded after pressurization and decompression of the cuff 3 during blood pressure measurement. For example, as shown in FIG. There may be an exponential decay with almost no vibration with the transition (exponential decay type). In this case, it is difficult to calculate the ratio R and the vibration frequency N described above.

Therefore, in such a case, an exponential decay type approximate curve can be calculated from the obtained blood pressure measurement data, and the slope dΔP / dt at a preset time t1 can be calculated. The inclination dΔP / dt is used as an index of blood vessel hardness, and it can be evaluated that the blood vessel is harder as the absolute value of the inclination dΔP / dt is smaller, and the blood vessel is softer as it is larger. The time t1 can be appropriately set by a preliminary experiment or the like.

Thus, the blood pressure measurement data varies depending on the individual difference of the person being measured. Therefore, for example, the calculation unit 8 determines whether or not the blood pressure measurement data vibrates with time (attenuated vibration type). If the blood pressure measurement data vibrates (attenuated vibration type), the difference is as described above. When the ratio R and the number of vibrations N are calculated from Ps _i and there is no vibration (exponential function attenuation type), the slope dΔP / d as described above.
By calculating t, it can be used as an index of vascular hardness.

Note that the measurement interval of the blood pressure measurement data can determine whether the blood pressure measurement data is the above-described attenuation vibration type or exponential function attenuation type, and in the case of the attenuation vibration type, the ratio R and the number of vibrations N described above from the blood pressure measurement data. In the case of the exponential decay type, the slope dΔP /
It can be set as appropriate so that dt can be calculated. For example, the measurement interval can be set in minutes such as 1 minute, 2 minutes, or 3 minutes by a preliminary experiment or the like.

  Further, since the hardness of the blood vessel wall is affected by the environmental temperature, the behavior of the blood pressure measurement data varies depending on the environmental temperature. Therefore, from the viewpoint of appropriately evaluating the blood vessel hardness, it is preferable to obtain blood pressure measurement data of the person to be measured by the sphygmomanometer 2 with the environmental temperature being constant. For example, as described above, by maintaining the temperature of the blood pressure measurement room at a constant temperature higher than that of the standby room maintained at a constant temperature, the blood vessel hardness can be evaluated without being affected by variations in environmental temperature. It becomes possible.

  For example, by making the increase of the environmental temperature constant throughout the year (the temperature of the above-mentioned waiting room and blood pressure measurement room is constant), the blood vessel hardness index is not affected by the difference in environmental temperature between seasons. Can be calculated. In addition, for example, by setting the increase in the environmental temperature constant for each season, it is possible to calculate the blood vessel hardness index without being affected by the difference in the environmental temperature within the set season. The environmental temperature can be set as appropriate according to the measurement location, building structure, etc., in addition to the season.

  For example, when evaluating vascular hardness in winter, it is preferable that the room temperature of the waiting room and the blood pressure measurement room be higher than the outdoor temperature, and when evaluating vascular hardness in summer, the waiting room and blood pressure It is preferable that the temperature in the measurement chamber is lower than the outdoor temperature. In the case where the temperature in the room is raised so that the standby room and the blood pressure measurement room are kept at a constant temperature, for example, a heater having a heat source can be used as the temperature regulator 10.

  As the temperature regulator 10, a stove, a heater, or an air conditioner can be used. When using the above-mentioned waiting room and blood pressure measuring room, the temperature regulator 10 can be provided in each of the waiting room and the blood pressure measuring room to adjust to a constant temperature. In this case, when the constant temperature of the standby chamber is T1 and the constant temperature of the blood pressure measurement chamber is T2 (predetermined temperature) higher than T1, the environmental temperature is, for example, as shown in FIG. Step changes as shown.

  The temperature raising method by the heat source is not particularly limited. In addition, for example, a stove is used as the temperature regulator 10, and the blood pressure measurement chamber is changed in the temperature T1 to T2 by an exponential change as shown in FIG. Can also be raised. In this case, blood pressure measurement can be started at the same time as the environmental temperature is raised, and blood pressure measurement can be performed until the environmental temperature reaches temperature T2.

  In addition, the ambient temperature can be raised from the temperature T1 to T2 using a rectangular (pulse-like) change as shown in FIG. In this case, blood pressure measurement is started as the environmental temperature rises, and the environmental temperature falls during blood pressure measurement. For example, blood pressure measurement can be started simultaneously with drinking hot drinking water such as hot water, whereby the blood pressure can be measured before the temperature in the body surrounding the blood vessel rises and falls.

  The temperature T1 can be set to 14 ° C. and the temperature T2 can be set to 19 ° C., for example, but the temperatures T1 and T2 are particularly limited as long as the blood vessel hardness index can be calculated from the blood pressure measurement data. However, it can be appropriately set by a preliminary experiment or the like.

  In addition, for example, by storing a parameter for increasing the environmental temperature in the storage unit 7 and inputting a set temperature on the display unit 9, the calculation unit 8 reads the parameter stored in the storage unit 7 and adjusts the temperature. The device 10 can also be activated.

  As described above, the temperature regulator 10 changes the ambient temperature of the blood vessel to a predetermined temperature (for example, the temperature T2 described above), pressurizes the blood vessel with the sphygmomanometer 2 and then depressurizes the blood pressure to measure blood pressure over time. 8, because the blood vessel hardness index is calculated based on the amount of change in blood pressure measured by the sphygmomanometer 2 from the previous measurement time point for each measurement time point, the blood pressure measurement is started at the start of the change in the environmental temperature. can do. As a result, since the blood vessel hardness index can be calculated by capturing a transient state in which the inner diameter of the blood vessel changes from the start of blood pressure measurement, it is possible to appropriately evaluate the blood vessel hardness.

  Here, blood pressure is measured over time by repeating pressurization and decompression of blood vessels at predetermined intervals, and a blood vessel hardness index is calculated by the calculation unit 8 from the blood pressure measurement data thus obtained. Therefore, the blood vessel hardness can be more appropriately evaluated. Further, in the above, the maximum blood pressure and the minimum blood pressure at one measurement time are measured for one pressurization and decompression, and the blood vessel hardness is calculated. However, if the blood vessel hardness index can be calculated from the blood pressure measurement data, The blood pressure measurement method, measurement time point, and the like are not particularly limited.

  Here, since the environmental temperature is raised to a predetermined temperature (for example, the temperature T2 described above), the blood vessel hardness index can be calculated by capturing a transient state where the blood vessel expands (the inner diameter of the blood vessel increases). Thereby, it becomes possible to evaluate the blood vessel hardness more appropriately.

Further, here, the calculation unit 8 sequentially calculates the difference Ps _i from the blood pressure at the immediately previous measurement time point for each measurement time point, and based on the sum of the absolute values of the calculated difference Ps _i (addition value A). Since the blood vessel hardness index (ratio R) is calculated, the magnitude of the blood vessel vibration can be grasped as a numerical value. Thereby, the blood vessel hardness can be evaluated in more detail.

Here, the ratio R is calculated by dividing the added value A by the blood pressure P ₀ at the start of measurement. However, if the magnitude of blood vessel vibration can be calculated, the additional value A is It is also possible to calculate the ratio R by dividing by the blood pressure showing the maximum value among the measurement time points.

Further, here, the calculation unit 8 causes the number of times N1 when the difference Ps _i changes from 0 or more to less than 0 compared to the previous measurement time, and the number of times N2 when the difference Ps _i changes from less than 0 to 0 or more, Since the blood vessel hardness index (vibration frequency N) is calculated based on the above, the frequency of blood vessel vibration can be grasped as a numerical value. Thereby, the blood vessel hardness can be evaluated in more detail. Here, the larger one of the number of times N1 and N2 is calculated as the number of times of vibration N. However, if the frequency of blood vessel vibration can be calculated, only one of the number of times N1 and N2 is calculated. It is also possible.

  As described above, the ratio R and the number of vibrations N are calculated here as the blood vessel hardness index. However, if the blood vessel hardness can be evaluated based on the amount of variation from the immediately previous measurement time point for each measurement time point. From the blood pressure measurement data obtained by the sphygmomanometer 2, other factors can be used as an index of blood vessel hardness. In addition, for example, an index of blood vessel hardness can be calculated by discrete Fourier transform or the like based on blood pressure measurement data.

  Here, since the temperature regulator 10 maintains a predetermined temperature (for example, the above-described temperature T2) at a constant temperature and measures the blood pressure with the sphygmomanometer 2 under the environmental temperature maintained at the constant temperature, the blood vessel It is possible to avoid the influence of the variation in the environmental temperature on the hardness evaluation. As described above, the method for increasing the environmental temperature is not limited to this.

  That is, for example, by making the relationship between time and temperature rise constant even in the above-described exponential temperature rise, and by making the relationship between time and temperature change constant even in a rectangular temperature change, It is possible to avoid the influence of the variation in the environmental temperature on the hardness evaluation.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of this invention. For example, in the above-described embodiment, the blood pressure is measured at the same time that the environmental temperature is raised, but the blood pressure can also be measured at the same time that the environmental temperature is lowered. In this case, a blood vessel hardness index can be calculated by capturing a transient state in which the inner diameter of the blood vessel becomes small.

  For example, blood pressure measurement can be started simultaneously with the environmental temperature being lowered stepwise, and in this case, for example, the temperature of the blood pressure measurement chamber described above can be set to a temperature lower than that of the standby chamber. In addition, the environmental temperature can be lowered exponentially. In this case, for example, a cooler can be used as the temperature regulator 10.

  In addition, when raising and lowering | hanging environmental temperature, the air conditioner which has a heating and cooling function can also be used, for example. Also, the ambient temperature can be lowered rectangularly, and in this case, blood pressure measurement can be started simultaneously with drinking cold drinking water such as cold water.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further in detail, this invention is not specifically limited to the following Example.

<Acquisition of blood pressure measurement data>
An air conditioner is used as the temperature regulator 10 and moves from the waiting room set at 14 ° C. to the blood pressure measuring chamber set at 19 ° C., and at the same time is pressurized by the sphygmomanometer 2 of the vascular hardness evaluation system 1 shown in FIG. The blood pressure of the measurement subject is measured for each pressurization and depressurization, and three blood pressure measurement data (sample) Nos. 1, no. 2 and no. 3 was obtained.

At this time, sample No. Time t (minutes) elapsed from the start of decompression of the first cuff 3 in 1, maximum blood pressure Pmax (mmHg) at each measurement time point, minimum blood pressure Pmin (mmHg) at each measurement time point, and t = 0 at each measurement time point Table 1 shows the measurement numbers (i) indicating the order from. FIG. 6 shows a graph showing the relationship between time and maximum blood pressure, and FIG. 7 shows a graph showing the relationship between time and minimum blood pressure.

Sample No. The time t (minutes) elapsed from the start of the first decompression of the cuff 3 in 2, the maximum blood pressure Pmax (mmHg) at each measurement time point, the minimum blood pressure Pmin (mmHg) at each measurement time point, and t = 0 at each measurement time point Table 2 shows the measurement numbers (i) indicating the order from. FIG. 8 shows a graph showing the relationship between time and maximum blood pressure, and FIG. 9 shows a graph showing the relationship between time and minimum blood pressure.

Sample No. 3, the time t (minutes) elapsed from the start of the first decompression of the cuff 3, the maximum blood pressure Pmax (mmHg) at each measurement time point, the minimum blood pressure Pmin (mmHg) at each measurement time point, and the order from t = 0 The measurement numbers (i) shown are shown in Table 3. A graph showing the relationship between time and maximum blood pressure is shown in FIG. 10, and a graph showing time and minimum blood pressure is shown in FIG.

<Sample No. Analysis of blood pressure measurement data and calculation of an index of vascular stiffness>
Next, from the measurement data of maximal blood pressure obtained in Table 1 and FIG. 6, the calculation unit 8 shown in FIG. Thus, the blood pressure difference Ps _i (Ps ₁ , Ps ₂ , Ps ₃ and Ps ₄ ) was calculated by Ps _i = P _i −P _i−1 . The results are shown in Table 4.

From Table 4, among Ps _{1 to} Ps ₄ , the number N1 of changes from Ps _i-1 ≧ 0 to Ps _i <0 is N1 = 0 and Ps _i-1 <0 to Ps _i ≧ 0. Since the number of times N2 is N2 = 1, the number of times of vibration N is calculated as N = 1 by taking the larger one of N1 and N2. Further, since the added value A, which is the sum of absolute values of Ps _{1 to} Ps ₄ , is calculated as A = 23, the ratio R of the added value A to the blood pressure P ₀ at the start of measurement is R = 23/137 = It is calculated as 0.17 (see Table 10).

On the other hand, in the same way for the minimum blood pressure, from the measurement data of the minimum blood pressure obtained in Table 1 and FIG. 7, the blood pressure between each measurement time point of measurement number (i) = 1 to 4 and the previous measurement time point. Difference Ps _i (Ps ₁ to Ps ₄ ) was calculated by Ps _i = P _i −P _i−1 . The results are shown in Table 5.

From Table 5, among Ps _{1 to} Ps ₄ , the number N1 of changes from Ps _i-1 ≧ 0 to Ps _i <0 is N1 = 1 and Ps _i-1 <0 to Ps _i ≧ 0. Since the number of times N2 is N2 = 1, the number of times of vibration N is calculated as N = 1. Further, since the added value A is calculated as A = 16 from Ps _{1 to} Ps ₄ , the ratio R of A to P ₀ is calculated as R = 16/85 = 0.19 (see Table 11).

<Sample No. Analysis of blood pressure measurement data and calculation of an index of blood vessel hardness>
Next, from the measurement data of the maximum blood pressure obtained in Table 2 and FIG. 1, the difference Ps _i (Ps ₁ to Ps ₄ ) of blood pressure from the previous measurement time at each measurement time of measurement numbers (i) = 1 to 4 is expressed as Ps _i = P _i −P Calculated by _i-1 . The results are shown in Table 6.

According to Table 6, among Ps _{1 to} Ps ₄ , the number N1 of changes from Ps _i-1 ≧ 0 to Ps _i <0 is N1 = 1, and Ps _i-1 <0 is changed to Ps _i ≧ 0. Since the number of times N2 is N2 = 2, the number of times of vibration N is calculated as N = 2. Further, since the added value A is calculated as A = 34 from Ps _{1 to} Ps ₄ , the ratio R of A to P ₀ is calculated as R = 34/141 = 0.24 (see Table 10).

On the other hand, in the same way for the minimum blood pressure, from the measurement data of the minimum blood pressure obtained in Table 2 and FIG. 9, the blood pressure between each measurement time point of measurement number (i) = 1 to 4 and the immediately previous measurement time point. Difference Ps _i (Ps ₁ to Ps ₄ ) was calculated by Ps _i = P _i −P _i−1 . The results are shown in Table 7.

From Table 7, among Ps _{1 to} Ps ₄ , the number N1 of changes from Ps _i-1 ≧ 0 to Ps _i <0 is N1 = 1 and Ps _i-1 <0 to Ps _i ≧ 0. Since the number of times N2 is N2 = 2, the number of times of vibration N is calculated as N = 2. Further, since the added value A is calculated as A = 20 from Ps _{1 to} Ps ₄ , the ratio R of A to P ₀ is calculated as R = 20/88 = 0.23 (see Table 11).

<Sample No. Analysis of blood pressure measurement data and calculation of blood vessel hardness index in 3>
Next, from the measurement data of the maximum blood pressure obtained in Table 3 and FIG. 1 and no. 2 and the measurement number (i) = 1 to 4 at each measurement time point, the blood pressure difference Ps _i (Ps ₁ to Ps ₄ ) between the previous measurement time point and Ps _i = P _It calculated by _i- Pi _-1 . The results are shown in Table 8.

From Table 8, among Ps _{1 to} Ps ₄ , the number N1 of changes from Ps _i-1 ≧ 0 to Ps _i <0 is N1 = 2 and Ps _i-1 <0 to Ps _i ≧ 0. Since the number of times N2 is N2 = 1, the number of times of vibration N is calculated as N = 2. Further, since the added value A is calculated as A = 47 from Ps _{1 to} Ps ₄ , the ratio R of A to P ₀ is calculated as R = 47/136 = 0.35 (see Table 10).

On the other hand, for the minimum blood pressure, from the measurement data of the minimum blood pressure obtained in Table 3 and FIG. 11, the blood pressure difference Ps _i (Ps ₁ to Ps ₄ ) was calculated by Ps _i = P _i −P _i−1 . The results are shown in Table 9.

From Table 9, among Ps _{1 to} Ps ₄ , the number N1 of changes from Ps _i-1 ≧ 0 to Ps _i <0 is N1 = 2 and Ps _i-1 <0 to Ps _i ≧ 0. Since the number of times N2 is N2 = 1, the number of times of vibration N is calculated as N = 2. Further, since the added value A is calculated as A = 32 from Ps _{1 to} Ps ₄ , the ratio R of A to P ₀ is calculated as R = 32/82 = 0.39 (see Table 11).

<Sample No. 1-No. Evaluation of vascular hardness in 3>
Sample No. 1-No. For the maximum blood pressure of 3, the added value A, the blood pressure P ₀ , the ratio R, and the vibration frequency N calculated from the above are shown in Table 10, and the relationship between the vibration frequency N and the ratio R is shown in FIG.

  As shown in Table 10 and FIG. 1-No. As a result of calculating the ratio R and the number of vibrations N from the measurement data of the maximum blood pressure, 2 and sample no. 3 is sample no. Compared to 1, the ratio R was large, and the number of vibrations N was also large. As a result, sample no. 2 and sample no. 3 is sample No. The blood vessels are softer than 1, in other words, sample no. No. 1 is sample no. 2 and sample no. It can be evaluated that the blood vessel is harder than 3.

  Sample No. 2 and Sample No. 3, the number of vibrations N is the same. 3 is sample No. Since the ratio R is larger than 2, the sample No. 3 is sample No. It can be evaluated that the blood vessel is softer than 2.

Next, sample no. 1-No. For the minimum blood pressure of 3, the added value A, blood pressure P ₀ , ratio R and number of vibrations N calculated above are shown in Table 11, and the relationship between the number of vibrations N and the ratio R is shown in FIG.

  As shown in Table 11 and FIG. 1-No. As a result of calculating the ratio R and the number of vibrations N from the measurement data of the minimum blood pressure, 2 and sample no. 3 is sample no. Compared to 1, the ratio R was large and the number of vibrations N was also large. As a result, sample no. 2 and sample no. 3 is sample No. It can be evaluated that the blood vessel is softer than 1.

  Sample No. 2 and Sample No. 3, the number of vibrations N is the same. 3 is sample No. Since the ratio R is larger than 2, the sample No. 3 is sample No. It can be evaluated that the blood vessel is softer than 2.

  As a result, Sample No. 1 to Sample No. 3, sample no. 3, sample no. 2, Sample No. It was found that in the order of 1, it can be relatively evaluated that the blood vessel is soft. It was also found that the vascular hardness can be evaluated by calculating the vascular hardness index using any of the measurement data of the maximum blood pressure and the minimum blood pressure.

<Acquisition of blood pressure measurement data>
As in Example 1, the blood pressure of the measurement subject was measured by repeatedly applying pressure and depressurization with the sphygmomanometer 2 while moving from the waiting room set at 14 ° C. to the blood pressure measuring chamber set at 19 ° C., Blood pressure measurement data (sample) No. 4 was obtained.

At this time, sample No. 4, the time t (minutes) elapsed from the start of decompression of the first cuff 3, the maximum blood pressure Pmax (mmHg) at each measurement time, the minimum blood pressure Pmin (mmHg) at each measurement time, and t = 0 at each measurement time Table 12 shows the measurement numbers (i) indicating the order from. FIG. 14 is a graph showing the relationship between time and maximum blood pressure, and FIG. 15 is a graph showing the relationship between time and minimum blood pressure. In this example, sample No. 4 of the sample No. 3 to be compared.

<Sample No. Analysis of blood pressure measurement data and calculation of blood vessel hardness index in 3>
Next, from the measurement data of the maximum blood pressure obtained in Table 3 and FIG. 10 described above, at each measurement time point of measurement number (i) = 1 to 6, in the same manner as in Example 1, between the previous measurement time points. Thus, the blood pressure difference Ps _i (Ps ₁ , Ps ₂ , Ps ₃ , Ps ₄ , Ps ₅ and Ps ₆ ) was calculated by Ps _i = P _i −P _i−1 . The results are shown in Table 13.

From Table 13, among Ps _{1 to} Ps ₆ , the number N1 of changes from Ps _i-1 ≧ 0 to Ps _i <0 is N1 = 2, and the number of changes from Ps _{i -1} <0 to Ps _i ≧. Since N2 is N2 = 2, the vibration frequency N is calculated as N = 2. Further, since the added value A is calculated as A = 56 from Ps _{1 to} Ps ₆ , the ratio R of A to P ₀ is calculated as R = 56/136 = 0.41 (see Table 17).

On the other hand, in the same way for the minimum blood pressure, from the measurement data of the minimum blood pressure obtained in Table 3 and FIG. 11, the blood pressure between each measurement time point of measurement number (i) = 1 to 6 and the immediately preceding measurement time point. The difference Ps _i (Ps ₁ to Ps ₆ ) was calculated by Ps _i = P _i −P _i−1 . The results are shown in Table 14.

From Table 14, among Ps _{1 to} Ps ₆ , the number N1 of changes from Ps _i-1 ≧ 0 to Ps _i <0 is N1 = 2 and Ps _i-1 <0 to Ps _i ≧ 0. Since the number of times N2 is N2 = 2, the number of times of vibration N is calculated as N = 2. Further, since the added value A is calculated as A = 42 from P _{1 to} P ₆ , the ratio R of A to P ₀ is calculated as R = 42/82 = 0.51 (see Table 18).

<Sample No. Analysis of blood pressure measurement data in 4 and calculation of an index of blood vessel hardness>
Next, from the measurement data of the maximal blood pressure obtained in Table 12 and FIG. 14, at each measurement time point of measurement number (i) = 1 to 6, in the same manner as described above, between the previous measurement time points. The blood pressure difference Ps _i (Ps ₁ to Ps ₆ ) was calculated by Ps _i = P _i −P _i−1 . The results are shown in Table 15.

From Table 15, among Ps _{1 to} Ps ₆ , the number N1 of changes from Ps _i-1 ≧ 0 to Ps _i <0 is N1 = 1, and Ps _i-1 <0 is changed to Ps _i ≧ 0. Since the number of times N2 is N2 = 2, the number of times of vibration N is calculated as N = 2. Further, since the added value A is calculated as A = 34 from Ps _{1 to} Ps ₆ , the ratio R of A to P ₀ is calculated as R = 34/125 = 0.27 (see Table 17).

On the other hand, in the same way for the minimum blood pressure, from the measurement data of minimum blood pressure obtained in Table 12 and FIG. The difference Ps _i (Ps ₁ to Ps ₆ ) was calculated by Ps _i = P _i −P _i−1 . The results are shown in Table 16.

From Table 16, among Ps _{1 to} Ps ₆ , the number N1 of changes from Ps _i-1 ≧ 0 to Ps _i <0 is N1 = 1, and Ps _i-1 <0 is changed to Ps _i ≧ 0. Since the number of times N2 is N2 = 1, the number of times of vibration N is calculated as N = 1. Further, since the added value A is calculated as A = 11 from Ps _{1 to} Ps ₆ , the ratio R of A to P ₀ is calculated as R = 11/74 = 0.15 (see Table 18).

<Sample No. 3 and no. Evaluation of vascular hardness in 4>
Sample No. 1-No. For the maximum blood pressure of 3, the added value A, blood pressure P ₀ , ratio R, and number of vibrations N calculated above are shown in Table 17, and the relationship between the number of vibrations N and the ratio R is shown in FIG.

  As shown in Table 17 and FIG. 3 and no. 4, the ratio R and the number of vibrations N were calculated from the measurement data of the maximum blood pressure. 3 is sample no. Compared to 4, the number of vibrations N was the same, but the ratio R was large. As a result, sample no. 3 is sample No. It can be evaluated that the blood vessel is softer than 4.

Next, sample no. 1-No. For the minimum blood pressure of 3, the added value A, blood pressure P ₀ , ratio R, and number of vibrations N calculated above are shown in Table 18, and the relationship between the number of vibrations N and the ratio R is shown in FIG.

  As shown in Table 18 and FIG. 3 and no. 4, the ratio R and the number of vibrations N were calculated from the measurement data of the minimum blood pressure. 3 is sample no. Compared with 4, the ratio R was large and the number of vibrations N was also large. As a result, sample no. 3 is sample No. It can be evaluated that the blood vessel is softer than 4.

  As a result, Sample No. 3 and Sample No. In sample 4, sample no. 3, sample no. It was found that in the order of 4, it can be relatively evaluated that the blood vessel is soft. It was also found that the vascular stiffness can be evaluated by calculating the vascular stiffness index using either the maximum blood pressure or the minimum blood pressure measurement data with respect to time.

<Acquisition of blood pressure measurement data>
In this example, the sample No. For blood pressure 4, the measurement interval was shorter than that in Example 2, and blood pressure measurement data was obtained.

At this time, sample No. 4, the time t (minutes) elapsed from the start of decompression of the cuff 3, the maximum blood pressure Pmax (mmHg) at each measurement time point, the minimum blood pressure Pmin (mmHg) at each measurement time point, and t = 0 at each measurement time point Table 19 shows the measurement numbers (i) indicating the order.

<Sample No. Analysis of blood pressure measurement data in 4 and calculation of an index of blood vessel hardness>
From the measurement data of the maximum blood pressure obtained in Table 19, the difference Ps _i of the blood pressure from the immediately preceding measurement time at each measurement time of measurement number (i) = 1 to 12 as in Example 1 and Example 2. (Ps ₁ , Ps ₂ , Ps ₃ ,... Ps ₁₁ and Ps ₁₂ ) were calculated by Ps _i = P _i −P _i−1 . The results are shown in Table 20.

From Table 20, among Ps _{1 to} Ps ₁₂ , the number N1 of changes from Ps _i-1 ≧ 0 to Ps _i <0 is N1 = 4, and Ps _i-1 <0 is changed to Ps _i ≧ 0. Since the number of times N2 is N2 = 4, the number of times of vibration N is calculated as N = 4. Further, since the added value A is calculated as A = 54 from Ps _{1 to} Ps ₁₂ , the ratio R of A to P ₀ is calculated as R = 54/125 = 0.43 (see Table 22).

On the other hand, in the same way for the minimum blood pressure, from the measurement data of the minimum blood pressure obtained in Table 19, the difference Ps of the blood pressure from the previous measurement time at each measurement time (measurement number (i) = 1 to 12). _i a (Ps ₁ ~Ps _12), the _{Ps i = P i -P i-} 1, was calculated. The results are shown in Table 21.

From Table 21, among Ps _{1 to} Ps ₁₂ , the number N1 of changes from Ps _i-1 ≧ 0 to Ps _i <0 is N1 = 4, and Ps _i-1 <0 is changed to Ps _i ≧ 0. Since the number of times N2 is N2 = 4, the number of times of vibration N is calculated as N = 4. Further, since the added value A is calculated as A = 53 from Ps _{1 to} Ps ₁₂ , the ratio R of A to P ₀ is calculated as R = 53/74 = 0.72 (see Table 23).

Sample No. Table 22 shows the added value A, blood pressure P ₀ , ratio R and number of vibrations N calculated for the maximum blood pressure of No. Table 23 shows the added value A, the blood pressure P ₀ , the ratio R, and the number of vibrations N calculated for the minimum blood pressure of 4.

  As shown in Tables 22 and 23, the ratio R and the vibration frequency N can be calculated in more detail by increasing the measurement time point. Thereby, it is guessed that it becomes possible to evaluate blood vessel hardness in detail. In addition, such sample No. 4 with the same measurement interval and measurement time as those described above. 1-No. No. 3 is calculated by calculating the ratio R and the vibration frequency N. 1-No. It is presumed that a more detailed evaluation of vascular hardness will be possible for 4.

  Sample No. By acquiring new blood pressure measurement data at the same measurement interval and measurement time as in FIG. It is presumed that the blood vessel hardness can be evaluated in more detail between 4 and the newly obtained sample.

  According to the present invention, blood vessel hardness can be appropriately evaluated.

1 Blood vessel hardness evaluation system 2 Blood pressure monitor (blood pressure measuring means)
3 Cuff 4 Pump 5 Pressure sensor 6 Control unit 7 Storage unit 8 Calculation unit (calculation means)
9 Display unit 10 Temperature controller (temperature adjustment means)

Claims (12)

Temperature adjusting means for changing the environmental temperature of the blood vessel to a predetermined temperature;
A blood pressure measuring means for measuring the blood pressure over time by pressurizing the blood vessel and then reducing the pressure;
A blood vessel hardness evaluation system comprising: calculation means for calculating an index representing the magnitude of the amplitude of the damped vibration as blood vessel hardness index from blood pressure data that undergoes damped vibration measured by the blood pressure measuring means. The calculation means calculates a difference between a blood pressure value obtained at each measurement time point and a blood pressure value obtained at a measurement time point immediately before each measurement time point, and based on a sum of absolute values of the calculated difference values. The blood vessel hardness evaluation system according to claim 1, wherein an index representing the magnitude of the amplitude of the damped vibration is calculated . The vascular hardness evaluation system according to claim 1 , wherein the calculation unit further calculates an index representing the vibration frequency of the damped vibration from the damped blood pressure data as a vascular hardness index . The calculation means calculates a difference between a blood pressure value obtained at each measurement time point and a blood pressure value obtained at a measurement time point immediately before each measurement time point, and the difference arranged in time series is from 0 to less than 0 The blood vessel hardness according to claim 3 , wherein an index representing the vibration frequency of the damped vibration is calculated based on the first number of times of change and the second number of times of change from less than 0 to 0 or more. Evaluation system. It said temperature adjusting means, vascular stiffness evaluation system according to any one of claims 1 to 4, characterized in that raising the environmental temperature to the predetermined temperature. The temperature adjusting means maintains the predetermined temperature at a constant temperature;
The blood vessel hardness evaluation system according to any one of claims 1 to 5, wherein the blood pressure is measured by the blood pressure measurement means under the environmental temperature maintained at the constant temperature. The blood pressure is measured over time by pressurizing and depressurizing the blood vessel at the ambient temperature of the blood vessel changed to a predetermined temperature, and an index indicating the magnitude of the amplitude of the damped vibration is obtained from the measured damped blood pressure data. the method of calculating the blood vessel hardness index and calculating as an index of vascular stiffness. The difference between the blood pressure value obtained at each measurement time point and the blood pressure value obtained at the measurement time point immediately before each measurement time point is calculated, and the amplitude of the damped oscillation is calculated based on the sum of absolute values of the calculated difference values. The method for calculating a blood vessel hardness index according to claim 7, wherein an index representing the size of the blood vessel is calculated . 9. The blood vessel hardness index calculation method according to claim 7 , wherein an index representing the vibration frequency of the attenuated vibration is further calculated as an index of blood vessel hardness from the damped blood pressure data . The difference between the blood pressure value obtained at each measurement time point and the blood pressure value obtained at the measurement time point immediately before each measurement time point is calculated, and the difference in time series is changed from 0 to less than 0. The blood vessel hardness index calculation method according to claim 9 , wherein an index representing the frequency of the damped vibration is calculated based on the number of times and the second number of times changed from less than 0 to 0 or more . The blood vessel hardness index calculation method according to claim 7, wherein the environmental temperature is raised to the predetermined temperature . 12. The blood vessel hardness index calculation method according to claim 7, wherein the predetermined temperature is maintained at a constant temperature, and the blood pressure is measured at the environmental temperature maintained at the constant temperature. .

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