JP2009189424A - Blood pressure measuring instrument and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide data which can make a user judge the reliability of the individual measured value led out of a blood pressure measuring instrument. <P>SOLUTION: The blood pressure measuring instrument is equipped with a cuff for oppressing a blood pressure measuring region, a pressure control means for increasing and decreasing the pressure in the cuff, a pressure sensor for detecting the pressure in the cuff, a pulse wave signal detecting means for extracting the time series data of the pulse wave signal superposed on the pressure in the cuff detected by the pressure sensor in the process of increasing or decreasing the pressure in the cuff by the pressure control means, a relational expression deriving means for deriving the relational expression between pulse wave amplitude and inner and outer pressure difference of a blood vessel on the basis of a change in a plurality of the one-cycle pulse wave signals contained in the data during a period, when at least the cuff pressure is larger than a systolic blood pressure value, in the time series data of the extracted pulse wave signal, and a degree-of-variation deriving means for deriving the degree of variation of blood pressure on the basis of the pressure value corresponding to the difference between the pulse wave amplitude in the extracted pulse wave signal and the pulse wave amplitude derived from the relational expression. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technique for measuring blood pressure based on a change in pressure pulse wave that is detected when a cuff is attached to a measurement site and the cuff pressure is changed, and in particular, the degree of fluctuation in systolic blood pressure. It is related with the technique which estimates this.

  Blood pressure measurement is very important in the treatment of hypertension. According to the hypertension treatment guideline of WHO / ISH, the degree of hypertension is divided when the minimum unit of the blood pressure value of the blood pressure classification is 5 mmHg, and fine treatment is required. On the other hand, blood pressure has a characteristic that changes greatly due to various causes such as activity amount, conversation, mental anxiety, tension, flirting, surprise, patience, drinking, smoking, and cold, in addition to pathological reasons.

  White coat hypertension, which is now widely known, is a phenomenon in which blood pressure rises regardless of the etiology due to sympathetic excitement caused by anxiety and tension in front of doctors and nurses. In addition, blood pressure can be greatly increased by exercise such as immediately after rushing to the clinic. Currently, in order to deal with these blood pressure fluctuations, a blood pressure monitor (ABPM: Ambulatory Blood Pressure Monitoring) that carries around 24 hours and measures and records blood pressure at 30-minute or 60-minute intervals is used (for example, Patent Document 1). Alternatively, measures are taken such as measuring blood pressure at a place other than the clinic, such as having a home blood pressure meter purchased and taking blood pressure at home, and comparing it with the blood pressure measured at the clinic. However, since these methods are time consuming and troublesome, in normal medical care, for example, a value measured once with a sphygmomanometer installed in a waiting room, or a value measured once during medical examination in a medical office Judging blood pressure.

In addition, blood pressure fluctuations include fluctuations based on individual behavior patterns such as one year, one month, 24 hours, etc. Recently, blood pressure when sleeping and blood pressure when waking up and active or waking up in the morning There are also studies that can be used to determine the risk of organ damage from the difference in blood pressure. There are also examples of observing and treating these blood pressure fluctuations, but these are investigations on special cases of hypertension. A major influencing factor in normal blood pressure measurement is blood pressure fluctuation related to tension.
Japanese Patent Laid-Open No. 11-47103

  However, the conventional blood pressure measuring device only displays the measured blood pressure value and does not know whether the blood pressure fluctuates due to tension or other reasons. For this reason, accurate blood pressure measurement has to be repeated several times over time, and there is a problem that the burden on the patient is large. In addition, when the above-mentioned ABPM is used, there is a cost in addition to the treatment cost, and it takes time until diagnosis, and there is a case where a rapid treatment cannot be performed.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a user with information capable of determining the reliability of each derived measurement value. In particular, it is an object to provide the user with information regarding the degree of blood pressure fluctuation due to the tension of the measurement subject or other reasons.

  In order to solve the above-described problems, the blood pressure measurement device of the present invention has the following configuration. That is, in the blood pressure measurement device, the cuff for compressing the blood pressure measurement site, the pressure control means for pressurizing or depressurizing the inside of the cuff, the pressure sensor for detecting the pressure in the cuff, and the pressure control means In the process of pressurizing or depressurizing the cuff, pulse wave signal extracting means for extracting time series data of the pulse wave signal superimposed on the pressure in the cuff detected by the pressure sensor, and the time series of the extracted pulse wave signal Deriving a relational expression for deriving a relational expression between the pulse wave amplitude and the intravascular / external pressure difference based on a change in a plurality of one-period pulse wave signals included in data in a period where at least the cuff pressure is greater than the systolic blood pressure value. Variation amount deriving means for deriving a blood pressure variation amount based on a pressure value corresponding to a difference between the pulse wave amplitude in the extracted pulse wave signal and the pulse wave amplitude derived based on the relational expression , Characterized in that it comprises a.

  In order to solve the above-described problems, a method for controlling a blood pressure measurement device according to the present invention has the following configuration. That is, a control method of a blood pressure measurement device comprising a cuff for compressing a blood pressure measurement site, pressure control means for pressurizing or depressurizing the inside of the cuff, and a pressure sensor for detecting the pressure in the cuff. A pulse wave signal extraction step for extracting time series data of a pulse wave signal superimposed on the pressure in the cuff detected by the pressure sensor in the process of pressurizing or depressurizing the cuff by the pressure control means; The relationship between the pulse wave amplitude and the intravascular external pressure difference based on the change of a plurality of one-cycle pulse wave signals included in the data of the period when at least the cuff pressure is greater than the systolic blood pressure value A relational expression deriving step for deriving an expression, and a blood pressure fluctuation amount is derived based on a pressure value corresponding to a difference between the pulse wave amplitude in the extracted pulse wave signal and the pulse wave amplitude derived based on the relational expression. A variation amount deriving step that, characterized in that it comprises a.

  ADVANTAGE OF THE INVENTION According to this invention, the information which can judge the reliability of each measured value derived | led-out by the blood-pressure measuring apparatus can be provided to a user. In particular, it is possible to provide the user with information regarding the degree of blood pressure fluctuation due to the tension of the measurement subject or other reasons.

  The blood pressure measurement device of the present invention will be described with reference to the drawings based on a preferred embodiment. Here, an example of a blood pressure measurement device using the triple cuff method will be described.

<Overview>
When a human is nervous, for example, blood pressure fluctuations synchronized with respiration occur. Therefore, information that enables determination of the degree of tension is provided to the measurer based on a blood pressure change at a frequency (0.15 to 0.5 Hz) at which respiration affects.

<Device configuration>
FIG. 4 is a block diagram illustrating the blood pressure measurement device according to the first embodiment. The cuff body 201 includes a cloth cuff member 202 that is detachably provided to a blood pressure measurement site including the upper arm, and a male (hook) illustrated by a broken line at an end of the cuff member 202 on the measurement site contact side. A type) hook-and-loop fastener 203 is provided, and a female (loop-type) hook-and-loop fastener 204 having the same position and area as the blood-blocking air bag on the surface opposite to the measurement site contact side is provided. The cuff member 202 is wound around the upper arm as shown in the figure, and each hook-and-loop fastener is locked, so that the cuff body 201 can be attached and detached. Here, the hook-and-loop fastener is merely an example, and other members may be used, or a configuration in which the cuff body is provided in a method of forming a tubular shape and inserting the upper arm may be employed.

  Inside the cuff member 202, a hemostatic air bag 208 shown in broken lines is laid to compress the entire blood pressure measurement site. In addition, a sub air bag 207 shown in a broken line having a narrower width is laid on the side in contact with the blood pressure measurement site of the ischemic air bladder 208 to compress the heart H side of the blood pressure measurement site. A first buffer member 209 that attenuates vibration of the sub air bag 207 is provided between the sub air bag 207 and the ischemic air bag 208.

  In addition, the air bag 208 for ischemia is laid at a substantially central part on the side where the blood pressure measurement site is in contact, compresses the central part of the blood vessel at the blood pressure measurement part and slightly downstream, and detects a pulse wave at the central part and slightly downstream. A cuff body 201 is configured by laying a pulse wave detection air bag 205 shown by a broken line.

  In order to pressurize and depressurize the cuff main body 201, the cuff main body 201 is provided with the blood-blocking air bag 208 by the second pipe 212 and the pipe 215, and the pulse wave detection air bag 205 of the cuff main body 201 is the first. A pump 223 which is a pressure increasing / decreasing means is connected to the sub air bag 207 of the cuff body 201 via a pipe 211 and a fluid resistor 214 via a third pipe 213 and an on-off valve 216. A pressure sensor 231 serving as a cuff pressure detecting means for obtaining a cuff pressure signal from a change in pressure of the pulse wave detection air bag 205 is connected to the pulse wave detection air bag 205 via the first pipe 211. Yes. A third pipe 213 is connected to the sub air bag 207.

  The first pipe 211, the second pipe 212, and the third pipe 213 are made of a soft tube and are detachably provided from the main body 230 via the connector 210.

  A pump 223 and a quick exhaust valve / constant speed exhaust valve 222 are connected to the cross-branching portion 220. The rapid exhaust valve / constant speed exhaust valve 222 is connected to the control unit 248, and the on-off valve 216 is connected to the control unit 246, and the quick exhaust valve / constant speed exhaust valve 222 is an electromagnetic valve in response to a command from the central control unit 235. The opening area is controlled, and the on-off valve 216 is opened / closed by an electromagnetic on-off valve.

  The pump 223 is driven in accordance with power supply from a pump drive unit 249 connected to the motor M, introduces external air into the pump through the opening 223a, pressurizes, and pressurizes air through the cross-branch unit 220. Is sent to the pipe 215 and the third pipe part 213a so that each air bag can be pressurized.

  FIG. 3 is a cross-sectional view in the longitudinal direction (the direction in which the upper arm extends) of the cuff (triple cuff) of the blood pressure measurement device according to the first embodiment. The cuff according to the modified example is provided in a large cuff 1 for blood vessel ischemia (corresponding to the air bag 208 for ischemia), a small cuff 2 for pulse wave detection (corresponding to the air bag 205 for pulse wave detection), and an upstream portion. A triple cuff including the sub cuff 3 (corresponding to the sub air bag 207). It is shown that the blood vessel 100 is blocked at the portion Q by the pressurized large cuff 1 and subcuff 3 for blood vessel ischemia, and the blood flow from the upstream side 100a to the downstream side 100b is suppressed.

  The force that squeezes the arm with the large cuff 1 is strongest at the center in the width direction of the cuff (part A in FIG. 3, hereinafter simply referred to as the cuff center A), and weakens as it approaches both ends. Then it becomes almost 0. However, compared with the case of the double cuff that does not include the sub-cuff 3, the difference is that the invasion of blood flow in the section indicated by “B” in FIG.

  The small cuff 2 is provided at the cuff central portion in the width direction of the cuff and slightly downstream A, so that the intravascular pressure change (intravascular volume change) in this portion is best captured. In the specification, “cuff pressure” means the pressure in the cuff, but is substantially equal to the compression force of the arm at the cuff central portion A in the cuff width direction. It is also the pressure from the cuff applied to the blood vessel under the cuff center A.

  The rapid exhaust valve / constant speed exhaust valve 222 has a structure in which the opening area is varied by the strength of electromagnetic force in order to realize a pressure reduction speed of 2 to 4 mmHg per second, and by obtaining a PWM drive signal from the control unit 248 Arbitrary decompression speed can be set.

  Via the fluid resistor 214, the ischemic pressure signal from the ischemic bladder 208 having attenuated the pulse wave component and the pressure change of the pulse wave detecting bladder 205 are input to the pressure sensor 231 which is a cuff pressure detecting means. The pressure sensor 231 is connected to a means for supplying a constant current to the pressure sensor 231 and a pressure measuring unit 232 for amplifying an electric signal. The pressure measuring unit 232 further converts an analog signal into a digital signal A. A / D converter 233 is connected and configured to output a digital signal to the central control unit 235 as a cuff pressure signal.

  The central control unit 235 includes a RAM 238 that reads and writes measurement data and analysis results, a pulse wave processing unit 239 that detects a superimposed pulse wave signal from the cuff pressure signal, and a cuff (an air bag for ischemia, a pulse wave). A cuff pressure control unit 240 that pressurizes and depressurizes the pressure of the detection air bag (sub air bag), a blood pressure measurement unit 241 that determines the blood pressure from the detected pulse wave change and the ischemic cuff pressure signal, and displays the measured blood pressure value as a blood pressure A ROM 236 that stores various control programs that can be read by the central control unit 235 includes a display control unit (not shown) for displaying on the means 237. The RAM 238 also functions as a work area for programs processed in the central control unit 235.

  The central control unit 235 is connected to a control unit that controls the on-off valves of the pump and the quick exhaust valve / constant speed exhaust valve 222 described above.

  Further, the power supply from the power supply unit 243 including the dry battery is configured such that each operation necessary for blood pressure measurement can be performed by supplying power to each unit by the central control unit 235 by operating the switch 242.

  In the blood pressure measurement apparatus configured as described above, various measurement control programs stored in advance in the ROM 236 can be read out by the central control unit 235 and operated as in a flowchart of a blood pressure measurement routine described later.

<Operation of the device>
FIG. 5 is an operation flowchart of the cuff pressurizing routine.

  First, the cuff body 201 is attached to the upper arm portion. When a measurement start switch 242 (not shown) is pressed, the opening area of the quick exhaust valve / constant speed exhaust valve 222 is fully opened, and the open / close valve 216 is opened to exhaust each air bag.

  In step S401, when the exhaust of the residual air in each air bag is completed, the pressure sensor 231 is zero-set (initialized).

  In step S402, the on-off valve 216 is kept open, and the rapid exhaust valve / constant speed exhaust valve 222 is fully closed. With the above, preparation for pressurization of the cuff (the air bag for ischemia, the air bag for detecting the pulse wave, the sub air bag) is completed, and the pump 223 is energized in step S403.

  In step S404, it is checked whether or not the specified pressure (pressure that inflates the sub air bag 207 so as to reduce the cuff edge effect without being an obstacle to ischemia) is reached. When the specified pressure is reached, the opening and closing is performed in step S405. Valve 216 is closed.

  In step S406, it is determined whether or not the cuff pressure has reached the pressurization set value. When the cuff pressure reaches the pressurization set value, the process proceeds to step S407 and the pump drive is stopped. In this manner, the pump 223 is continuously driven so that the pressure of the air bag 408 for ischemia becomes a set pressure value that is 20 to 30 mmHg higher than the expected systolic blood pressure.

  In step S408, a blood pressure value measurement routine to be described later is executed.

  FIG. 6 is a flowchart showing a blood pressure value measurement routine. In the blood pressure value measurement routine, information indicating the degree of blood pressure fluctuation is also derived.

  When the process proceeds to step S620, constant speed exhaust is started by the rapid exhaust valve / constant speed exhaust valve 222. The cuff pressure controller 240 uses the signal from the cuff pressure detector to change the opening area of the rapid exhaust valve / constant exhaust valve 222 so that the decompression speed becomes 2 to 3 mmHg / sec, and starts constant speed decompression. Is done.

  In step S621, the cuff pressure is obtained from the cuff pressure detector. In step S622, a pulse wave signal is detected. Then, the process proceeds to step S623, and the cuff pressure and the pulse wave amplitude are set as a set and sequentially stored in the RAM 238 as time series data.

  FIG. 1 is a graph showing a state in which a pulse wave signal is superimposed on the cuff pressure in the process of reducing the cuff pressure. This graph shows how the magnitude and shape of the pulse wave signal change as the cuff pressure decreases. FIG. 2 is a diagram showing a change of the pulse wave amplitude value superimposed on the cuff pressure in the process of reducing the cuff pressure together with the change of the cuff pressure. It is shown that in the process of reducing the cuff pressure, the pulse wave amplitude value gradually increases, and after passing through the point M where the maximum amplitude value appears, the pulse wave amplitude value tends to gradually decrease.

  In step S624, the time-series data of the pulse wave amplitude stored in step S623 is inspected. Then, when the point M is detected, in the time series data before the point M, for example, the cuff pressure value at the time when the amplitude suddenly increases stepwise beyond a specified ratio is determined as the systolic blood pressure value.

  In step S626, after the systolic blood pressure value is determined, the pulse wave signal is detected again. Then, the process proceeds to step S627, and the cuff pressure and the pulse wave amplitude are set as a set and sequentially stored in the RAM 238 as time series data.

  In step S628, the time-series data of the pulse wave amplitude stored in step S627 is inspected. Then, in the time series data after the point M, for example, the cuff pressure value at the time corresponding to 60% of the pulse wave amplitude (PA) at the point M is determined as the diastolic blood pressure value.

  In step S629, the opening area of the rapid exhaust valve / constant speed exhaust valve 222 is fully opened, and the on / off valve 216 is opened to bring the cuff to atmospheric pressure.

  In step S630, the time-series data of the pulse wave amplitude stored in step S627 is examined, and the degree of blood pressure fluctuation is estimated according to the process described below.

  In step S631, information regarding the systolic blood pressure value, the diastolic blood pressure value determined in the above-described step, and the determined degree of blood pressure fluctuation is displayed on the liquid crystal display unit 237, and the series of blood pressure measurement operations is terminated.

  FIG. 7 is a detailed flowchart for determining the degree of blood pressure fluctuation.

  In step S1701, the intravascular external pressure difference is calculated for the time series data of the pulse wave amplitude stored in the RAM 238. Specifically, the difference between the measured systolic blood pressure value (internal pressure) and the detected cuff pressure value (external pressure) is calculated for each one-cycle pulse wave signal detected at systolic blood pressure or higher.

  When the cuff pressure is sufficiently high, the compliance of the cuff is small and the volume change can be regarded as a pressure change. Therefore, the pulse wave amplitude, which is the pressure change when the systolic blood pressure is equal to or greater than that, is regarded as a volume change, and the relationship between the intravascular external pressure difference (= systolic blood pressure-cuff pressure) is examined, and the elastic characteristics of the blood vessels (pressure volume characteristics) Is derived. Here, it is derived based on measurement data from systolic blood pressure + 40 mmHg to systolic blood pressure in the cuff decompression process.

  In step S1702, for example, as shown in FIG. 8, the intravascular external pressure difference (= (systolic blood pressure−cuff pressure)) when the systolic blood pressure is zero (reference point) on the x axis is a pressure change on the y axis. A certain pulse wave amplitude value is plotted on the liquid crystal display unit 237.

  In step S1703, an approximate curve / regression curve (for example, exponential curve, quadratic curve) is obtained based on time-series data of pulse wave amplitude values. In general, it can be considered that the pulse wave amplitude increases as the intra-vascular external pressure difference decreases, so approximation by a monotonically increasing curve is sufficient. Thereby, the change characteristic in the frequency lower than the typical frequency range (0.15-0.5 Hz) in respiration can be extracted.

  When the intra-vascular external pressure difference is close to zero (that is, near systolic blood pressure), the volume change in the blood vessel thrust direction (direction along the blood vessel) may change greatly, and the volume change in the blood vessel radial direction may not be accurately reflected. Therefore, it is preferable to derive the approximate curve from the data component excluding the analysis prohibited section where the intravascular external pressure difference is from zero to the specified pressure.

  In step S1704, the difference between the detected pulse wave amplitude and the approximate curve obtained in step S1703 is converted into a pressure value acting on the blood vessel. The pressure change acting on the blood vessel in response to the change in the pulse wave amplitude is obtained by solving an approximate curve obtained by using y as the pulse wave amplitude and x as the intra-vascular external pressure difference. That is, by inputting the amplitude change caused by the blood pressure fluctuation in y, that is, the difference between the actual amplitude of the detected pulse wave and the approximate curve, the intravascular / external pressure difference (= change in pressure acting on the blood vessel) as x is obtained. It is done.

  FIG. 8 is a diagram showing an example of derivation of the intravascular external pressure difference corresponding to the pulse wave amplitude difference. The difference between the detected actual amplitude (S point) and the approximate curve (= difference when there is no blood pressure fluctuation) is assumed to be Amax. A line parallel to the X axis is drawn on the approximate curve from the detected actual amplitude (S point), and the difference in the X coordinate between the intersection and the S point is defined as Bmax. At this time, Bmax indicates the intravascular external pressure difference corresponding to Amax. This calculation is performed for each one-cycle pulse wave, and Bmax for each one-cycle pulse wave is derived.

  In step S1705, the maximum Bmax in each of the plus direction and the minus direction is detected for Bmax derived in step S1704.

  In step S1706, the difference (sum of absolute values) of the maximum Bmax in the positive direction and the negative direction determined in step S1705 is derived as the blood pressure fluctuation range.

  Regarding the estimated fluctuation range, the change in blood vessel volume due to the pressure on the upstream side of the air bag (the heart side when the cuff is attached) when the blood vessel is closed at the center of the ischemic air bag This includes not only the action of the thrust but also the action in the thrust direction. In order to reduce the influence of the volume change in the thrust direction, the influence of the action in the thrust direction does not become zero even if the pulse wave within the specified pressure from the systolic blood pressure is not used. Therefore, it is preferable to derive a correction formula using comparison data between the continuous blood pressure measured simultaneously in a certain population and the estimated value obtained by this method, and further correct the estimated fluctuation range.

  In step S1707, the blood pressure fluctuation amplitude estimated value obtained in step S1706 is corrected, and the estimated value is converted into a ratio (for example, percentage) to the systolic blood pressure value measured in step S624 and stored in the RAM 238. Thereafter, in step S631, the ratio is displayed on the liquid crystal display unit 237 as information on the degree of blood pressure fluctuation, for example, as shown in FIG.

  As described above, the blood pressure measurement device according to the present invention is a process of measuring a blood pressure by cuffing a measurement site and measuring a change in pulse wave amplitude detected when the cuff pressure is higher than a systolic blood pressure. The relationship (approximate curve) between the blood pressure value of the period and the pressure of the difference between the cuff pressure is obtained. Then, the fluctuation amount of the blood pressure is estimated from the difference between the pulse wave amplitude change derived from this relationship and the pulse wave amplitude change affected by the actually measured respiration.

  Thereby, together with the systolic blood pressure measurement value, the current degree of blood pressure fluctuation can be predicted, and the degree of tension can be estimated. The estimated degree of tension provides an indication of whether the measured blood pressure value may be used reliably for blood pressure treatment or whether it needs to be measured again in a more resting state. As a result, more accurate hypertension treatment can be performed. Compared with the case where ABPM is performed, the patient burden, the expense burden, and the diagnosis time can be reduced, so that rapid treatment can be performed.

  In addition, since the blood pressure fluctuation is expressed as a ratio to the measured systolic blood pressure, the degree of the influence of the blood pressure fluctuation can be easily grasped compared to the actual measurement value display, and remeasurement can be determined instantaneously. In addition, by providing the data use prohibition section, it is possible to eliminate the influence of the volume change in the vascular radial direction, and it is possible to derive a more accurate approximate curve.

  The above embodiments are merely examples, and are not intended to limit the scope of the present invention, and various modifications are possible. For example, in the above-described embodiment, the blood pressure is measured in the decompression process after the cuff is pressurized at a pressure higher than the systolic blood pressure. However, the blood pressure may be measured in the pressurization process from a pressure lower than the diastolic blood pressure.

It is a figure which shows a mode that the pulse-wave signal is superimposed on the cuff pressure in the pressure reduction process of the cuff pressure. It is the figure which showed the mode of the change of the pulse wave amplitude value superimposed on a cuff pressure in the pressure reduction process of a cuff pressure with the change of the cuff pressure. It is sectional drawing of the longitudinal direction of the cuff of the blood pressure measuring device which concerns on 1st Embodiment. It is a figure showing composition of a blood pressure measuring device concerning a 1st embodiment. It is an operation | movement flowchart of the cuff pressurization routine of the blood-pressure measurement apparatus which concerns on 1st Embodiment. It is a detailed flowchart of a blood pressure value measurement routine. It is a detailed flowchart for determining the degree of blood pressure fluctuation. It is a figure which shows an example of derivation | leading-out of the intravascular external pressure difference corresponding to a pulse wave amplitude difference. It is a figure which shows an example of the result display of a blood pressure measurement.

Claims (6)

A cuff to compress the blood pressure measurement site;
Pressure control means for pressurizing or depressurizing the inside of the cuff;
A pressure sensor for detecting the pressure in the cuff;
In the process of pressurizing or depressurizing the cuff by the pressure control means, a pulse wave signal extracting means for extracting time series data of a pulse wave signal superimposed on the pressure in the cuff detected by the pressure sensor;
Based on changes in a plurality of one-cycle pulse wave signals included in data of a period in which at least the cuff pressure is greater than the systolic blood pressure value among the time-series data of the extracted pulse wave signals, the pulse wave amplitude and the intravascular external pressure difference A relational expression deriving means for deriving a relational expression of
A fluctuation amount deriving means for deriving a blood pressure fluctuation amount based on a pressure value corresponding to a difference between the pulse wave amplitude in the extracted pulse wave signal and the pulse wave amplitude derived based on the relational expression;
A blood pressure measurement apparatus comprising:   2. The blood pressure measurement device according to claim 1, wherein the relational expression deriving unit derives the relational expression as an approximate curve corresponding to a change in the plurality of one-period pulse wave signals.   The blood pressure measurement device according to claim 2, wherein the approximate curve is expressed by a monotonically increasing function. The variation amount derivation means includes:
A difference between the pulse wave amplitude in the extracted pulse wave signal and the pulse wave amplitude derived based on the relational expression is derived for each of the plurality of one-period pulse wave signals,
The blood pressure measurement according to any one of claims 1 to 3, wherein a pressure value corresponding to a maximum pulse wave amplitude among a plurality of derived pulse wave amplitude differences is derived as the blood pressure fluctuation amount. apparatus. Blood pressure value determining means for determining a systolic blood pressure value based on changes in a plurality of one-period pulse wave signals included in the time-series data of the extracted pulse wave signal;
The relational expression deriving unit uses data of a period in which the difference between the cuff pressure and the determined systolic blood pressure value is smaller than a predetermined value among the extracted time series data of the pulse wave signal for deriving the approximate expression. The blood pressure measurement device according to any one of claims 1 to 4, wherein the blood pressure measurement device is not. A control method of a blood pressure measurement device comprising a cuff for compressing a blood pressure measurement site, a pressure control means for pressurizing or depressurizing the inside of the cuff, and a pressure sensor for detecting the pressure in the cuff,
In the process of pressurizing or depressurizing the cuff by the pressure control means, a pulse wave signal extraction step of extracting time series data of a pulse wave signal superimposed on the pressure in the cuff detected by the pressure sensor;
Based on changes in a plurality of one-cycle pulse wave signals included in data of a period in which at least the cuff pressure is greater than the systolic blood pressure value among the time-series data of the extracted pulse wave signals, the pulse wave amplitude and the intravascular external pressure difference A relational expression deriving step for deriving a relational expression of
A fluctuation amount deriving step for deriving a blood pressure fluctuation amount based on a pressure value corresponding to a difference between the pulse wave amplitude in the extracted pulse wave signal and the pulse wave amplitude derived based on the relational expression;
A method for controlling a blood pressure measurement device comprising:

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