JP2008018035A - Apparatus for measuring pulse wave propagation speed, method for calculating pulse wave propagation speed, program and machine readable recording medium having program recorded thereon - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure a pulse wave propagation speed suggesting effective information for prognostic prediction. <P>SOLUTION: The apparatus 10 for measuring pulse wave propagation speed is provided with an HBP input part 36 for inputting a blood pressure value measured beforehand at home. On the basis of the pulse wave propagation speed calculated by a PWV calculation part 32 according to pulse waves actually measured in a consultation room, a blood pressure value measured by an OBP calculation part 33 at the time and the blood pressure value HBP at home are taken into consideration, and the pulse wave propagation speed is calculated by a PWVh calculation part 34. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a device for measuring the propagation speed of a pulse wave in an arterial wall (pulse wave propagation speed), a method for calculating a pulse wave propagation speed, a program, and a machine-readable recording medium on which the program is recorded. The present invention relates to a pulse wave velocity measuring device that acquires a pulse wave velocity, a method for calculating a pulse wave velocity, a program, and a machine-readable recording medium that records the program.

  The speed at which the pressure pulse wave propagates through the artery is referred to as pulse wave velocity PWV (PWV: Pulse Wave Velocity). The pulse wave propagation velocity PWV is theoretically expressed using the equation (1).

  In the actual measurement, the pulse wave propagation velocity PWV is required for the pulse wave to propagate between the two points such as the carotid artery-femoral artery and the brachial artery-ankle joint by the time difference Δt of arrival of the pulse wave, that is, between the two points. Dividing by time, that is, PWV = D / Δt can be calculated. The calculation formula is shown in Non-Patent Document 1.

  The pulse wave velocity PWV increases as the elastic modulus Et increases due to arteriosclerosis, and the increase in blood pressure also increases as the elastic modulus Et increases. That is, the pulse wave velocity PWV represents two cardiovascular risk factors, blood pressure and arterial stiffness, and is known to be useful as a prognostic indicator for patients.

Therefore, in Patent Document 1, the blood pressure is referred to in order to evaluate the measurement result of the pulse wave propagation speed based on the relationship between the pulse wave propagation speed PWV and the blood pressure.
JP 2002-301034 A Yoshiaki Masuda, “Clinical Arterial Wave”, published by Medical View, April 2003, p91-p92

  About blood pressure, blood pressure value HBP (HBP: Home Blood Pressure) measured in daily life at home, early morning / night is better than blood pressure value OBP (OBP: Office Blood Pressure) measured in the examination room It is known to be a prognostic predictor. Therefore, in order to measure the pulse wave velocity PWV that can represent a more accurate prognostic index, it is desirable to refer to the blood pressure value HBP. However, the pulse wave velocity PWV is not yet in a situation that can be measured at home due to problems such as a large measuring device, and thus the cardiovascular risk factor evaluated by the measured pulse wave velocity PWV. Remains a fusion of “blood pressure OBP and arterial stiffness”.

  Therefore, an object of the present invention is to provide an apparatus for measuring a pulse wave velocity that suggests useful information about prognosis prediction, a method for calculating the pulse wave velocity, a program, and a computer-readable recording medium storing the program. Is to provide.

  A pulse wave velocity measuring device according to an aspect of the present invention includes a pulse wave detection unit that simultaneously detects a pulse wave in each of two predetermined parts of the measurement subject's living body, a distance at which the pulse wave propagates between the two parts, and Based on the time required for the pulse wave to propagate between the two parts calculated based on the pulse wave detected by the pulse wave detector, the pulse wave propagation speed indicating the speed at which the pulse wave propagates between the two parts is calculated. Blood pressure-added propagation that calculates a pulse wave propagation speed that takes blood pressure into account using a propagation formula that includes a propagation speed calculation unit and a variable based on the pulse wave propagation speed calculated by the propagation speed calculation unit and the blood pressure of the measurement subject A speed calculator, and the variables are a first blood pressure measured under a first condition defined by the first measurement time and the first measurement location, a second measurement time and a second measurement location. Measured under the second condition specified in And it refers to a variable based on the difference between the second blood pressure.

Preferably, the first blood pressure is measured when the pulse wave velocity is measured in the examination room.
Preferably, the first measurement location refers to the examination room.

Preferably, the second measurement location refers to the measurement subject's home.
Preferably, in the pulse wave velocity measuring device, a storage medium in which the second blood pressure is stored in advance is detachably attached, and the second blood pressure is read from the attached storage medium.

  Preferably, in the process of adjusting the pressurization level for the measurement site, the blood pressure calculation unit further calculates a first blood pressure based on the pulse wave detected from the measurement site, and the pressurization level is set to the second blood pressure input in advance. Adjusted based on

Preferably, the second blood pressure refers to the blood pressure measured either in the early morning or at night.
Preferably, an output unit that outputs a measurement result of the pulse wave velocity is further included, and the output unit takes into account the pulse wave velocity calculated by the propagation velocity calculator and the blood pressure calculated by the blood pressure-added propagation velocity calculator. The measurement result is output using the measured pulse wave velocity.

  Preferably, the output unit associates the pulse wave propagation velocity calculated by the propagation velocity calculation unit with the pulse wave propagation velocity added with the blood pressure calculated by the blood pressure-added propagation velocity calculation unit, and outputs the measurement result. .

  Preferably, the apparatus further includes an output unit that outputs a measurement result of the pulse wave propagation velocity, and the output unit associates the pulse wave propagation velocity with the blood pressure calculated by the blood pressure-added propagation velocity calculation unit with the second blood pressure. Output the measurement results.

  Preferably, the output unit further outputs, for each age, information indicating the association between the pulse wave propagation speed in which the standard blood pressure is taken into account in the age and the standard second blood pressure in the age, together with the measurement result. .

  According to another aspect of the present invention, a method for calculating a pulse wave propagation velocity using a computer including a data input unit for inputting data given from the outside, an arithmetic unit, and an output unit for outputting data Is a data input step for inputting the pulse wave velocity and the blood pressure data of the measured person for the measurement subject's living body in advance by the data input unit, and the pulse wave velocity and blood pressure input by the data input step. The calculation unit outputs a calculation result of the blood pressure-added propagation speed calculating step for calculating the pulse wave propagation speed with the blood pressure taken into account and the calculation result of the blood pressure-added propagation speed calculating step using the output unit, A first blood pressure measured under a first condition defined at a first measurement time and a first measurement location, and a second measurement time Preliminary refers to variables based on the difference between the second blood pressure measured in the second condition defined by the second measurement position.

  According to still another aspect of the present invention, there is provided a program for causing a computer to execute the above-described method for calculating a pulse wave velocity.

  According to still another aspect of the present invention, there is provided a machine-readable recording medium recording a program for causing a computer to execute a method for calculating a pulse wave propagation velocity.

  According to the invention, when calculating the pulse wave propagation speed taking into account the blood pressure from the pulse wave propagation speed calculated based on the pulse wave detected from the actual measurement site by the pulse wave detection unit, different measurement conditions (time And the first blood pressure and the second blood pressure measured under the place) are used. Therefore, by setting the measurement conditions so that blood pressure measured in the daily life at home, early morning and night, which is an excellent prognostic predictor, can be used, the pulse suggests effective information on prognosis prediction. Wave propagation velocity can be measured or calculated.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Here, the measurement of blood pressure and pulse wave propagation velocity refers to calculation (estimation) according to a predetermined procedure using a signal (pulse wave) detected from a measurement site of the measurement subject.

  In each embodiment, the pulse wave velocity that takes into account blood pressure is calculated. For the calculation, a blood pressure measured from the subject under a predetermined condition and a blood pressure measured from the subject under a condition different from the predetermined condition are used. The conditions for blood pressure measurement are determined by the time for blood pressure measurement (daily life time zone, night time zone, early morning time zone, etc.) and the place for blood pressure measurement (examination room, measurement subject's home, etc.).

(Embodiment 1)
Referring to FIG. 1, pulse wave velocity measuring device 10 includes systems 10A and 10B, an A / D (Analog / Digital) converter 8, a CPU (Central Processing Unit) 20, an LCD (Liquid Crystal Display), and the like. Display unit 21 and blood pressure value OBP are separately operated from an HBP input I / F (Interface) 22 for inputting blood pressure value HBP measured at home, etc., and various instructions and data for measurement are operated from the outside. An operation unit 23 for inputting, a memory 24 for storing various programs and data, a timer 25 for timing, an electrocardiographic sensor 26, and a communication I / F 27 for communicating with an external device (such as a computer) are included. .

  The systems 10A and 10B have the same configuration. The system 10A is detected via a cuff (arm band) 1A and a cuff 1A for pressurizing a measurement site of a pulse wave in the living body of the measurement subject by an air pressure (hereinafter referred to as a cuff pressure) in a built-in air bag. The pressure sensor 2A for detecting a change in pressure and outputting it as a pulse wave signal, the amplifier 5A for amplifying and outputting the pulse wave signal output from the pressure sensor 2A, and the pressure (air pressure) level by the cuff 1A Pump 3A and valve 4A for adjustment, pump drive circuit 6A for driving pump 3A, valve drive circuit 7A for adjusting opening and closing of valve 4, cuff 1A and valve 4A, pump 3A and pressure sensor 2A An air tube 30A is connected to each other.

  Similarly to system 10A, system 10B includes cuff 1B, pressure sensor 2B, pump 3B, valve 4B, amplifier 5B, pump drive circuit 6B, valve drive circuit 7B, and cuff 1B and valve 4B, pump 3B and pressure sensor 2B. An air tube 30B for connecting the two. Since the function of each part of the system 10B is the same as that of the system 10A, description thereof is omitted.

  The A / D converter 8 includes signal input ports I1 and I2, an output port O1 for outputting a signal input from the input port I1, and an output port O2 for outputting a signal input from the input port I2.

  Pulse wave signals output from amplifiers 5A and 5B are applied to input ports I1 and I2 of A / D converter 8, respectively. The A / D converter 8 inputs the signals given to the input ports I1 and I2 at the same time, converts the input analog signal into a digital signal, and converts the converted pulse wave signal through the output ports O1 and O2. To the CPU 20 simultaneously. The A / D converter 8 operates in synchronization with the sampling clock given from the CPU 20. The CPU 20 generates a sampling clock based on the timing data output from the timer 25 and supplies it to the A / D converter 8. The sampling clock has a frequency of, for example, 1 kilohertz or 500 hertz.

  The electrocardiographic sensor 26 is attached to a predetermined measurement site of the measurement subject in order to detect an electrocardiographic waveform. The electrocardiographic waveform data output from the electrocardiographic sensor 26 is given to the CPU 20. The CPU 20 analyzes the electrocardiographic waveform data input from the electrocardiographic sensor 26, and based on the analysis result, an appropriate pulse wave signal is given to the CPU 20 via the A / D converter 8, that is, the system It is determined whether an appropriate pulse wave is detected from the measurement site via each of 10A and 10B, and processing according to the determination result is performed. For example, when an irregular pulse is detected based on the analysis result of the electrocardiogram waveform, the pulse wave propagation velocity PWV calculated based on the pulse wave is not accurate. Therefore, the CPU 20 calculates the pulse wave propagation speed PWV, but outputs a message to the display unit 21 or the like indicating that the pulse wave propagation speed is not accurate because an arrhythmia has occurred along with the calculation result. Alternatively, the measurement of the pulse wave velocity PWV may be stopped, and since an arrhythmia is detected, a message indicating that the measurement of the pulse wave velocity PWV is to be stopped may be output. The pulse wave velocity measuring device 10 may not include the electrocardiographic sensor 26.

  FIG. 2 shows a functional configuration of the pulse wave velocity measuring device 10. Referring to FIG. 2, pulse wave velocity measuring device 10 includes a calculation unit 30 corresponding to CPU 20 and the like, an output unit 35 corresponding to display unit 21, an HBP input unit 36 corresponding to HBP input I / F 22, and a memory. 24 has a data storage unit 37 corresponding to 24. The calculation unit 30 includes a PWV / OBP calculation unit 31 and a PWVh calculation unit 34 for calculating a pulse wave propagation velocity taking into account the blood pressure value HBP (hereinafter referred to as pulse wave propagation velocity PWVh). The PWV / OBP calculation unit 31 includes a PWV calculation unit 32 and an OBP calculation unit 33 for calculating the pulse wave velocity PWV and the blood pressure value OBP.

  Here, the functions of the PWV / OBP calculation unit 31 and the PWVh calculation unit 34 in the calculation unit 30 are stored in the memory 24 in advance, and the CPU 20 reads the program from the memory 24 and executes it. Although the corresponding function is realized by this, all or part of the function may be realized by a hardware circuit.

  The pulse wave propagation speed PWVh indicates the pulse wave propagation speed calculated by incorporating the blood pressure value HBP into a variable for calculating the pulse wave propagation speed PWV. The data storage unit 37 displays the measurement subject's height data TH input by the operation unit 23, pulse wave signal data PW input by the CPU 20 via the A / D converter 8, and an image on the display unit 21. Therefore, display data DD stored in advance, data MAX indicating the maximum pressurization level referred to during blood pressure measurement, blood pressure values HBP and OBP, pulse wave propagation speeds PWV and PWVh, and the like are stored.

  The CPU 20 reads the data stored in the data storage unit 37 and transfers it to an external device such as a computer via the communication I / F 27.

  In the present embodiment, the pulse wave velocity PWV and the blood pressure value OBP are calculated by the PWV / OBP calculation unit 31. On the other hand, the blood pressure value HBP is measured in advance at home and input via the HBP input unit 36. The PWVh calculation unit 34 calculates the pulse wave propagation velocity PWVh based on the pulse wave propagation velocity PWV calculated by the PWV / OBP calculation unit 31 and the blood pressure value OBP input via the HBP input unit 36. The calculated pulse wave velocity PWVh is displayed by the output unit 35. Here, the output unit 35 has a display function. However, the output unit 35 may have a printing function instead of the display function, or may have both functions.

  FIG. 3 shows an overview of the pulse wave velocity measuring device 10. Referring to FIG. 3, pulse wave velocity measuring device 10 includes display unit 21, IrDA (Infrared Data Association) port 221 corresponding to HBP input I / F 22 (HBP input unit 36), memory card slot 222, and button group. 223, and buttons 231, 232 and 233 corresponding to the operation unit 23, an electrocardiographic sensor 26, a set of cuffs 1A and 1B attached to a measurement site, and a set of cuffs 11A and 11B. In the memory card slot 222, the memory card 224 is detachably attached from the outside, the data stored in the attached memory card 224 is read, and the read data is output to the CPU 20.

  The button 231 is operated to turn on / off the power of the pulse wave velocity measuring apparatus 10. The button 232 is operated to instruct the start / end of the measurement of the pulse wave velocity by the pulse wave velocity measuring device 10. The button 233 is operated to input the measurement subject's height data TH to the pulse wave velocity measuring apparatus 10.

  Here, two sets of cuffs (a set of cuffs 1A and 1B and a set of cuffs 11A and 11B) are provided. Thus, when measuring using two sets of cuffs, there are the following advantages. For example, if a stenosis of a blood vessel has occurred at a measurement site to which one set of cuffs is attached, pulse waves and blood pressure cannot be measured accurately. Instead, measurement is performed using another set of cuffs. Can be performed. Here, for example, it is assumed that cuffs 1A and 11A are used for the lower limbs (measurement sites for the left and right legs), and cuffs 1B and 11B are used for the upper limbs (measurement sites for the left arm and the right arm). Below, in order to demonstrate easily, the case where only the group of cuff 1A and 1B is provided is demonstrated.

  The blood pressure value HBP is input by the HBP input unit 36, for example, as follows. A blood pressure value HBP measured in advance in daily life at home or in the early morning / night is transmitted to the pulse wave velocity measuring device 10 by wireless communication from a portable blood pressure monitor (not shown) that is portable. . Examples of wireless communication include optical communication. That is, the home blood pressure monitor modulates the blood pressure value HBP into an infrared signal and outputs it. The output blood pressure value HBP is transferred (transmitted) according to IrDA and received by the IrDA port 221. The IrDA port 221 demodulates the received infrared signal and gives the blood pressure value HBP acquired based on the demodulation result to the CPU 20. Instead of IrDA, a communication method such as Bluetooth may be used.

  Moreover, not only wireless but wired communication using a cable may be used. The portable home sphygmomanometer transfers the blood pressure value HBP to the pulse wave velocity measuring device 10 via the cable.

  Alternatively, a removable memory card 224 that stores blood pressure values HBP measured with a home blood pressure monitor may be used. That is, the memory card 224 storing the measured blood pressure value HBP is removed from the home sphygmomanometer and mounted in the memory card slot 222 of the pulse wave velocity measuring device 10. The blood pressure value HBP read from the memory card 224 by the memory card slot 222 is given to the CPU 20.

  Alternatively, the measurement subject may operate the button group 223 and input the blood pressure value HBP. The input blood pressure value HBP is given to the CPU 20.

  Next, the measurement procedure according to this embodiment will be described with reference to the flowcharts of FIGS. These flowcharts are stored in advance in the memory 24 as programs, and the CPU 20 reads out these programs from the memory 24 and executes them, whereby measurement by the pulse wave velocity measuring device 10 is performed.

  FIGS. 4A and 4B show an example of a schematic procedure for measuring the pulse wave velocity PWV using the pulse wave velocity measuring apparatus 10 and another example. At the time of measurement, the button 231 is operated to turn on the power of the pulse wave velocity measuring device 10, and the measurement subject is in a state of being lying down and resting. Cuffs 1A and 1B are attached to the upper and lower limbs. Further, it is assumed that the button 233 is operated to input the measurement subject's height data TH, and the input data TH is stored in the data storage unit 37.

  In this state, when the button 232 is operated to start measurement, the OBP calculation unit 33 first measures the blood pressure value OBP (step S1). After the measurement of the blood pressure value OBP is completed, the pulse wave velocity PWV is subsequently measured by the PWV calculation unit 32 (S3). Subsequently, the blood pressure value HBP is input via the HBP input unit 36 (step S5). Thereafter, the pulse wave propagation velocity PWVh is calculated by the PWVh calculation unit 34 (step S7). Then, the calculated result or the measured result is output via the output unit 35 (step S9).

  FIG. 4B shows a measurement procedure different from that in FIG. In FIG. 4B, first, the blood pressure value HBP is input via the HBP input unit 36 (step S11). Based on the input blood pressure value HBP, the OBP calculation unit 33 determines the maximum pressurization level for the measurement site when measuring a blood pressure value OBP described later. For example, the maximum pressurization level is determined as systolic blood pressure + 30 mmHg indicated by the input blood pressure value HBP. The determined maximum pressure level data MAX is stored in the data storage unit 37.

  Next, the blood pressure value OBP is measured by the OBP calculating unit 33 using the determined maximum pressure level (step S15). Thereafter, the pulse wave propagation speed PWV is measured by the PWV calculation unit 32 using the measured blood pressure value OBP (step S17). Next, based on the measurement result, the pulse wave propagation velocity PWVh is calculated by the PWVh calculator 34 (step S19). And a measurement result or a calculation result is output via the output part 35 (step S21).

  As described above, according to the procedure of FIG. 4B, the maximum pressurization level necessary for measuring the blood pressure value OBP is determined based on the blood pressure value HBP of the person to be measured. It is possible to avoid the occurrence of inconveniences such as causing pain to the measurement subject due to the pressure being applied to the subject or being unable to accurately measure the blood pressure due to insufficient pressurization.

  In FIGS. 4A and 4B, the blood pressure value OBP is measured before measuring the pulse wave velocity PWV, but may be measured after that (but before measuring the pulse wave velocity PWVh). .

  With reference to FIGS. 5A and 5B, the procedure for measuring the blood pressure value OBP by the OBP calculating unit 33 will be described. The measurement procedure of FIG. 5A shows the detailed procedure of step S1 of FIG. 4A, and the measurement procedure of FIG. 5B shows the detailed procedure of step S15 of FIG. 4B.

  Referring to FIG. 5A, first, in a state where cuffs 1A and 1B are attached to a predetermined measurement site on the measurement subject and blood pressure measurement can be started, the button of pulse wave velocity measuring device 10 is pressed. When 231 is operated and the power is turned on, the pulse wave velocity measuring device 10 is initialized (step T1).

  Next, when the button 232 is operated to start measurement, the CPU 20 closes the valves 4A and 4B by the valve drive circuits 7A and 7B, and turns on the pumps 3A and 3B via the pump drive circuits 6A and 6B. Driving is started so as to supply air to the cuffs 1A and 1B. As a result, the cuff pressures of the cuffs 1A and 1B gradually increase (step T3). In the process of gradually pressurizing, the CPU 20 inputs a pulse wave signal detected via the pressure sensors 2A and 2B. When determining that the cuff pressure level has reached the predetermined level for blood pressure measurement based on the input pulse wave signal, the CPU 20 stops the pumps 3A and 3B via the pump drive circuits 6A and 6B, and then Then, the closed valves 4A and 4B are gradually opened via the valve drive circuits 7A and 7B, the air in the cuffs 1A and 1B is gradually exhausted, and the cuff pressure is gradually reduced (step T5). In the present embodiment, the blood pressure is measured in the cuff pressure slow depressurization process.

  First, in the process of gradually reducing the cuff pressure, the CPU 20 acquires the cuff pressure detection signal output from the pressure sensors 2A and 2B, and detects the pulse wave signal superimposed on the signal (step T7). At this time, the A / D converter 8 operates in accordance with a predetermined sampling clock based on the timer 25 under the control of the CPU 20, so that the pulse wave signals detected by the systems 10A and 10B are simultaneously input to the CPU 20. Next, the CPU 20 calculates the blood pressure (systolic blood pressure SBP (SBP), diastolic blood pressure DBP (DBP)) based on the pulse wave signal input in step T7, for example, according to the oscillometric method. (Step T9). The calculated blood pressure value indicates the blood pressure value OBP.

  When the blood pressure value OBP is calculated in step T9, the CPU 20 stores the calculated blood pressure value OBP in the data storage unit 37 (step T11). At this time, the valves 4A and 4B are fully opened, and the air in the cuffs 1A and 1B is exhausted rapidly. This completes a series of blood pressure measurements.

  Here, the blood pressure value OBP is calculated using each of the two systems 10A and 10B, but either one of the calculated blood pressure values OBP may be stored in the data storage unit 37 and the other may be discarded. Then, the average of the two blood pressure values OBP may be obtained and the average value may be stored in the data storage unit 37.

  The procedure in FIG. 5B is different from the procedure in FIG. 5A in that step T2 is provided between steps T1 and T3. Other procedures are the same as the processing in FIG. In step T <b> 2, the CPU 20 reads the maximum pressure level data MAX from the data storage unit 37. Next, in step T3, the CPU 20 continues to pressurize the measurement site with the cuffs 1A and 1B until the detected cuff pressure reaches the maximum pressurization level indicated by the read data MAX. When the detected cuff pressure reaches the maximum pressurization level, the process proceeds to the depressurization process of step T5. Thereby, the upper limit level of pressurization can be kept within an appropriate range. Therefore, the burden on the measurement subject during measurement can be reduced, and the measurement time can be shortened.

  FIG. 6 shows an example of a pulse wave waveform detected in the present embodiment. In FIG. 6, when the cuff 1A is worn on the upper right arm and the cuff 1B is worn on the right ankle, the elapsed time of pulse wave detection (elapsed measurement time) is taken on the horizontal axis, and each pulse wave is taken on the vertical axis. The amplitude of the waveform is taken. For example, even when pulse waves are detected at two measurement sites at the same time, it can be seen that there is a difference in the time during which the pulse waves are transmitted through the artery as shown in FIG.

  With reference to FIG. 7, the measurement (steps S3 and S17) of the pulse wave velocity PWV in FIGS. 4A and 4B will be described. Here, pressurization is performed in the same manner as the measurement of the blood pressure value OBP described above.

  First, similarly to the blood pressure measurement described above, the cuffs 1A and 1B are pressurized to a predetermined level or the maximum pressurization level indicated by the data MAX, respectively, and the pressure sensors 2A and 2B and the A / D converter in the decompression process. The pulse wave signal is measured (detected) via 8 (steps R1, R3 and R5). The detected pulse wave signal is sequentially stored as pulse wave data PW in the data storage unit 37 (R7). The pulse wave data PW indicates a change in the amplitude (mmHg) level of the pulse wave corresponding to the passage of time T as shown in FIG. The CPU 20 calculates the pulse wave propagation speed PWV based on the stored pulse wave data PW (step R9). Then, the calculated pulse wave propagation velocity PWV is stored in the data storage unit 37 (step R11). Thereby, the measurement of the pulse wave propagation velocity PWV ends.

  Although the pulse wave is sampled at the same time by the A / D converter 8, in FIG. 6, the pulse wave detected at the upper right arm at the upper stage and the right ankle at the lower stage are detected. The pulse wave is shifted by a predetermined time. In the present embodiment, the pulse wave velocity PWV is calculated as shown in FIG. 8 using this time lag (hereinafter referred to as time difference ΔT).

  FIG. 8 schematically shows the procedure for calculating the pulse wave velocity PWV by the PWV calculator 32 in step R9 of FIG. Referring to FIG. 8, the pulse wave propagation velocity PWV is a pulse wave sampled (detected) simultaneously at two points of measurement points A and B, which indicate two measurement parts to which cuffs 1A and 1B are attached. Calculated based on That is, the pulse wave propagation velocity PWV is calculated based on the time difference ΔT of the pulse wave detected simultaneously at two points and the distance (L) between the two points. Here, when the measurement is performed on an artery having a different path such as measurement between two points between the upper right arm and the right ankle, the distance L corresponds to a difference in distance from the heart between the two points. The distance L is obtained by estimation based on the data TH of the measurement subject's height read from the data storage unit 37.

  In FIG. 8, the time difference ΔT corresponds to 1/5 of the level from the rising point (baseline in the figure) of the detected pulse wave at point A to the peak value (maximum value) of the amplitude of the pulse wave. The time corresponding to the time point when the amplitude level reached and the detected pulse wave at the point B are 1/5 of the level from the rising point (baseline in the figure) to the peak value of the amplitude of the pulse wave. A difference ΔT from the time corresponding to the time when the corresponding amplitude level is reached is obtained, and is calculated according to PWV (m / s) = L / ΔT using the obtained time difference ΔT and the distance L. The calculated pulse wave propagation velocity PWV is stored in the data storage unit 37.

  Next, the procedure for calculating the pulse wave velocity PWVh by the PWVh calculator 34 will be described. The inventors present an equation (2) referring to an equation (3) proposed by Asmar et al., Which will be described later, as an arithmetic equation for calculating the pulse wave velocity PWVh.

PWVh = PWV + α ・ (HBP−OBP) + β (2)
(OBP: examination room blood pressure, HBP: home blood pressure, PWV: measured PWV value, α, β: some coefficient value)
(OBP and HBP are standardized by systolic blood pressure SBP, diastolic blood pressure DBP, pulse pressure, or mean blood pressure). In order to detect early morning hypertension and nocturnal hypertension that induce cardiovascular risk, the blood pressure value HBP measured during waking up or during sleep can be used. Therefore, the blood pressure values HBP and OBP used in Equation (2) indicate the systolic blood pressure SBP measured at home and the systolic blood pressure SBP measured in the examination room, respectively.

  It has been proposed that the relationship between the pulse wave velocity PWV, systolic blood pressure SBP, and age is schematically shown by the following equation (3).

  PWV (cm / s) = 7 × systolic blood pressure SBP (mmHg) + 9 × age −430 Equation (3). Details regarding this equation (3) are described in the literature by Asmar et al. (Asmar R et al, Hypertension, American Heart Association, Inc. 1995; 26: 485-490.).

  The above formula (2) can be converted into a formula (4) indicating a specific calculation formula by using the coefficient value of the formula (3). That is, Expression (4) indicates an expression when α = 7 and β = 0 in Expression (2).

PWVh = PWV + 7 × (HBP−OBP) (4)
The pulse wave velocity PWVh can also be calculated by the following procedure without being limited to the procedure calculated according to the above-described equation (4). That is, Formula (5) proposed by Bramwell-Hill can be used as a formula for calculating the pulse wave velocity by taking the blood pressure value HBP into account. Details of equation (5) are described in the literature by Bramwell-Hill (Bramwell JC, Hill AV, Proc. R. Soc. B, 1922, 298-306).

  In equation (5), by replacing the internal pressure change ΔP representing the effect of blood pressure measured in the examination room with a value represented by the blood pressure value HBP measured in the home, equation (5) It is converted into equation (6) for calculation.

(HSBP: systolic blood pressure SBP included in blood pressure HBP, HDBP: diastolic blood pressure DBP included in blood pressure HBP, OSBP: systolic blood pressure SBP included in blood pressure OBP, ODBP: diastolic included in blood pressure OBP Blood pressure DBP)
In this way, the PWVh calculation unit 34 reads the blood pressure value OBP and the pulse wave propagation velocity PWV from the data storage unit 37, and uses these read data and the blood pressure value HBP input via the HBP input unit 36, and the equation The pulse wave velocity PWVh is calculated according to (4) or equation (6). The calculated pulse wave velocity PWVh is stored in the data storage unit 37.

  9A to 9C show display examples on the display unit 21 of the measurement result of the pulse wave velocity by the output unit 35. FIG. Although only the pulse wave velocity is displayed here, the blood pressure value HBP or OBP may also be read from the data storage unit 37 and displayed.

  In FIG. 9A, numerical values indicated by the pulse wave propagation speeds PWV and PWVh read from the data storage unit 37 are displayed side by side.

  In the display example of FIG. 9B, the pulse wave propagation speeds PWV and PWVh are displayed in association with each other. Specifically, it is defined by two orthogonal axes (one of the two axes has the value of the pulse wave velocity PWV and the other axis has the value of the pulse wave velocity PWVh). In the coordinate plane, coordinates (PWV, PWVh) indicated by the pulse wave propagation speeds PWV and PWVh read from the data storage unit 37 are indicated by black dots.

  In FIG. 9B, the coordinate plane is divided into four sections with a certain value of each of the pulse wave propagation velocities PWV and PWVh (values that classify the value) as a threshold value, and a black dot is one of the four sections. Plotted into crab. Here, it is plotted in the hatched section of FIG. By confirming the section in which the black dots are plotted, it is possible to confirm at a glance whether the measured pulse wave velocity PWV and PWVh belong to the high value group or the low value group.

  For example, when plotted in the shaded area in FIG. 9B, the blood pressure value HBP measured in daily life at home or early morning / night is relatively high, and the pulse wave velocity PWVh is relatively high. Since it belongs to a group of values, it is predicted that the prognosis is poor.

  In FIG. 9C, the pulse wave velocity PWVh and the blood pressure value HBP are displayed in association with each other. Specifically, in the coordinate plane defined by the pulse wave propagation velocity PWVh and the blood pressure value HBP, for each age (20s, 30s,..., 70s), the pulse wave propagation indicating a standard value for the age. A curve defined by the combination of speeds PWV and PWVh is displayed. For example, when the measurement subject is assumed to be in his / her 40s, the measurement result (black dot) is plotted on the curve of his / her 60s in FIG. Since the actual age of blood vessels (the degree of progression of arteriosclerosis) can be reported, when a drug such as arteriosclerosis improvement is prescribed, the subject is motivated to take the drug. Will be made.

  9B and 9C are displayed on the basis of the display data DD read out from the data storage unit 37 by the output unit 35. .

  The measurement subject instructs the output unit 35 by inputting via the operation unit 23 which of FIGS. 9A to 9C the display mode of the measurement result of the pulse wave velocity is to be set. You may do it. Or you may make it the display mode in the display part 21 switch to FIG.9 (A)-(C) sequentially by switching operation via the operation part 23. FIG.

(Embodiment 2)
Referring to FIG. 10, the computer according to the second embodiment concentrates a display 47 such as an LCD (Liquid Crystal Display) or a CRT (Cathode Ray Tube), an input unit having a keyboard 41 and a mouse 42, and the computer itself. A CPU 40 for controlling the operation, a memory 48 including a ROM (Read Only Memory) or a RAM (Random Access Memory), a fixed disk 49, and an FD (Flexible Disk) 44 are detachably mounted. An FD driver 43 for accessing the FD 44, a CD-ROM (Compact Disc Read Only Memory) 46 is detachably mounted, a CD-ROM driver 45 for accessing the mounted CD-ROM 46, a communication line NT, and the computer A communication I / F 50 for communication connection is included. These units are connected for communication via a bus.

  The processing function of the calculation unit 30 including the PWVh calculation unit 34 for calculating the pulse wave propagation velocity PWVh described in the first embodiment is realized by a program. In the second embodiment, this program is stored in a computer-readable recording medium in FIG.

  In the second embodiment, the recording medium may be a memory required for processing by the computer shown in FIG. 10, for example, the memory 48. Alternatively, it may be a recording medium that is detachably attached to an external storage device of a computer. A program recorded in advance on a recording medium is read via an external storage device. The external storage device is the FD driver 43 or the CD-ROM driver 45, and the recording media are the FD 44 and the CD-ROM 46. In any case, the program recorded on each recording medium may be read and executed by the CPU 40, or read and executed in a predetermined program storage area (for example, a predetermined area of the memory 48) of FIG. After loading, the CPU 40 may read and execute from the area.

  Further, the computer transmits the pulse wave velocity PWV data transmitted via the communication I / F 27 by the pulse wave velocity measuring apparatus 10 of FIG. 1 through the communication line NT and the communication I / F 50, and the blood pressure in the examination room. The data of the value OBP and the data of the home blood pressure value HBP are received. The received data is stored in a predetermined area of the memory 48.

  The CPU 40 of the computer in FIG. 10 receives the pulse wave velocity measurement apparatus 10 and receives the pulse wave velocity PWV actually measured by the pulse wave velocity measurement apparatus 10 stored in a predetermined area of the memory 48 and the blood pressure value OBP. Using the HBP data, the pulse wave propagation velocity PWVh is calculated according to the flowchart of FIG. Then, the calculation result is displayed on the display 47. The display mode is, for example, as shown in FIG. The flowchart of FIG. 11 is executed by executing the program supplied as described above.

  In FIG. 11, first, in step Q1, the CPU 40 receives from the pulse wave velocity measuring device 10 via the communication I / F 50 data on the actually measured pulse wave velocity PWV, data on the blood pressure value OBP in the examination room, and Acquired by receiving home blood pressure HBP data. The received data is stored in a predetermined area of the memory 48. In step Q3, the data received from the memory 48 is read out, and the pulse wave propagation velocity PWVh is calculated based on the above-described equation (4) or equation (6) using the read data. In step Q5, the calculated pulse wave velocity PWVh and the like are output on the display 47 in accordance with the modes shown in FIGS.

  Here, the pulse wave velocity PWV and blood pressure values OBP and HBP data are transferred from the pulse wave velocity measuring device 10 to the computer via the communication line NT, but the transfer mode is not limited to this. For example, it may be transferred via a recording medium such as the FD 44 or the memory card 224.

  Here, a computer provided in the measurement subject's home or the like is assumed, but a portable computer such as a PDA (Personal Digital Assistant) or a portable information terminal such as a cellular phone may be used.

  The provided program product includes the program itself and a recording medium on which the program is recorded.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a hardware block diagram of the pulse wave velocity measuring device concerning an embodiment. It is a functional lineblock diagram of a pulse wave velocity measuring device concerning an embodiment. It is a general-view figure of the pulse wave velocity measuring device concerning an embodiment. (A) And (B) is a figure which shows the rough measurement procedure of the pulse wave velocity which concerns on embodiment. (A) And (B) is a figure which shows the measurement procedure by the OBP calculation part which concerns on embodiment. It is a figure which shows an example of the pulse wave waveform detected in this Embodiment. It is a processing flowchart for measuring the pulse wave velocity according to the embodiment. It is a figure which shows typically the calculation procedure of the pulse wave propagation velocity which concerns on embodiment. (A)-(C) are figures which show the example of a display of the measurement result of the pulse wave velocity which concerns on embodiment. It is a block diagram of the computer which concerns on embodiment. It is a flowchart which shows the pulse wave velocity calculation procedure by the computer which concerns on embodiment.

Explanation of symbols

  10 Pulse wave velocity measuring device, 22 HBP input I / F, PWV, PWVh Pulse wave velocity, HBP, OBP blood pressure, SBP systolic blood pressure, DBP diastolic blood pressure.

Claims (14)

A pulse wave detection unit that simultaneously detects a pulse wave in each of two predetermined parts of the measurement subject's living body;
Based on the distance that the pulse wave propagates between the two parts and the time required for the pulse wave to propagate between the two parts calculated based on the pulse wave detected by the pulse wave detector A propagation velocity calculation unit for calculating a pulse wave propagation velocity indicating a velocity at which the pulse wave propagates between,
A blood pressure-added propagation speed calculation unit that calculates a pulse wave propagation speed in which blood pressure is added, using a calculation formula that includes a variable based on the pulse wave propagation speed calculated by the propagation speed calculation unit and the blood pressure of the measurement subject. And comprising
The variable includes a first blood pressure measured under a first condition defined at a first measurement time and a first measurement location, and a second condition defined at a second measurement time and a second measurement location. The pulse wave velocity measuring apparatus which points out the variable based on the difference with the 2nd blood pressure measured below.   The pulse wave velocity measuring apparatus according to claim 1, wherein the first blood pressure is measured when calculating the pulse wave velocity.   The pulse wave velocity measuring device according to claim 1 or 2, wherein the first measurement location indicates an examination room.   The pulse wave velocity measuring device according to any one of claims 1 to 3, wherein the second measurement location indicates a home of the measurement subject. The pulse wave velocity measuring device is detachably mounted with a storage medium in which the second blood pressure is stored in advance.
The pulse wave velocity measuring device according to any one of claims 1 to 4, wherein the second blood pressure is read from the attached storage medium. A blood pressure calculation unit that calculates the first blood pressure based on a pulse wave detected from the measurement site in the process of adjusting the pressurization level for the measurement site;
The pulse wave velocity measuring device according to any one of claims 1 to 5, wherein the pressurization level is adjusted based on the second blood pressure input in advance.   The pulse wave velocity measuring device according to any one of claims 1 to 6, wherein the second blood pressure is a blood pressure measured either in the early morning or at night. An output unit for outputting the measurement result of the pulse wave velocity;
The output unit uses the pulse wave propagation velocity calculated by the propagation velocity calculation unit and the pulse wave propagation velocity to which the blood pressure calculated by the blood pressure-added propagation velocity calculation unit is added. The pulse wave velocity measuring device according to any one of claims 1 to 7, which outputs the pulse wave velocity.   The output unit associates the pulse wave propagation velocity calculated by the propagation velocity calculation unit with the pulse wave propagation velocity to which the blood pressure calculated by the blood pressure-added propagation velocity calculation unit is added, and displays a measurement result. The pulse wave velocity measuring device according to claim 8, which outputs the pulse wave velocity. An output unit for outputting the measurement result of the pulse wave velocity;
8. The output unit according to claim 1, wherein the output unit associates the pulse wave propagation velocity with the blood pressure calculated by the blood pressure-contained propagation velocity calculation unit with the second blood pressure, and outputs a measurement result. The pulse wave velocity measuring device according to claim 1. The output unit further includes:
The information which shows the correlation with the pulse wave velocity in which the said blood pressure standard in the said age was considered for every age, and the said 2nd blood pressure standard in the said age is output with the said measurement result. Pulse wave velocity measuring device. A method for calculating a pulse wave velocity using a computer,
The computer includes a data input unit for inputting data given from the outside, a calculation unit, and an output unit for outputting data,
The method
A data input step of inputting the pulse wave velocity and the blood pressure data of the measured person measured in advance for the living body of the measured person by the data input unit;
A blood pressure-added propagation speed calculating step of calculating a pulse wave propagation speed with the blood pressure taken into account by the calculation unit according to a calculation formula comprising the pulse wave propagation speed and the blood pressure input in the data input step;
An output step of outputting the calculation result of the blood pressure-added propagation speed calculation step using the output unit;
The variable includes a first blood pressure measured under a first condition defined at a first measurement time and a first measurement location, and a second condition defined at a second measurement time and a second measurement location. A method of calculating a pulse wave velocity, which indicates a variable based on a difference from the second blood pressure measured below.   A program for causing a computer to execute the method of calculating a pulse wave velocity according to claim 12.   A machine-readable recording medium recording a program for causing a computer to execute the method of calculating a pulse wave velocity according to claim 12.

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