JP5540829B2 - Blood pressure measuring device and method for controlling blood pressure measuring device - Google Patents

Description

  The present invention relates to a blood pressure measurement device and a control method for the blood pressure measurement device, and more particularly to a blood pressure measurement device that measures blood pressure using a volume compensation method and a control method for the blood pressure measurement device.

  Blood pressure is one of the indices for analyzing cardiovascular diseases, and risk analysis based on blood pressure is effective in preventing cardiovascular diseases such as stroke, heart failure and myocardial infarction. In particular, early morning hypertension, in which blood pressure rises in the early morning, is related to heart disease and stroke.

  Furthermore, it has been found that, among early morning hypertension, a symptom of a sudden rise in blood pressure between 1 hour and 1.5 hours after waking up, called morning surge, has a causal relationship with stroke. Thus, grasping the correlation between time (lifestyle) and blood pressure change is useful for risk analysis of cardiovascular diseases. Therefore, it is necessary to continuously measure blood pressure over a long period of time.

  In monitoring patients during and after surgery, and confirming the efficacy of antihypertensive drugs, it is very important to measure blood pressure continuously every heartbeat and monitor changes in blood pressure.

  Blood pressure measurement by the volume compensation method is performed as follows. The pressure in the cuff wrapped around the measurement site is detected so that the arterial volume at the measurement site is detected by a photoelectric sensor, etc., and the change in the arterial volume due to the arterial pressure (blood pressure) is always maintained at a constant arterial volume (control target value V0). Control by (cuff pressure). At this time, since the blood pressure and the cuff pressure are in an equilibrium state, the blood pressure (blood pressure waveform) can be continuously measured by measuring the cuff pressure. For accurate blood pressure measurement, it is necessary to accurately determine the control target value V0.

  In blood pressure measurement using a conventional volume compensation method, the control target value V0 is determined as follows. FIG. 12 is a graph showing the mechanical characteristics of the artery. In this figure, the horizontal axis represents the difference between blood pressure and cuff pressure (intra-arterial pressure difference Ptr), and the vertical axis represents the arterial volume.

  As shown in FIG. 12, the control target value V0 is an arterial volume at a point where the blood pressure and the cuff pressure are balanced (point of Ptr = 0 in the figure). As shown in FIG. 12, the mechanical compliance of the artery is maximized at the point of Ptr = 0. Therefore, the change in arterial volume due to blood pressure fluctuation at this point is maximized. Therefore, the arterial volume and the arterial volume change are detected while gradually increasing the cuff pressure, and the average value of the arterial volume of one heartbeat at the point where the arterial volume change becomes maximum is determined as the control target value V0 ( Patent Document 1).

  However, as shown in FIG. 13 (cited from FIG. 2 of Non-Patent Document 1), the mechanical characteristics of arteries are different in the direction of increasing and decreasing blood pressure, that is, there is hysteresis (see Non-Patent Document 1). ).

  In the blood pressure waveform of FIG. 14, if the increase / decrease in blood pressure is replaced with the intra-arterial / external pressure difference Ptr, when the cuff pressure is constant, when the blood pressure increases (when the diastolic blood pressure changes to the systolic blood pressure), Ptr is On the contrary, when the blood pressure decreases (when changing from systolic blood pressure to diastolic blood pressure), Ptr decreases.

  On the other hand, if cuff pressure increase / decrease is replaced with intra-arterial / external pressure difference Ptr, when cuff pressure decreases, when cuff pressure decreases (when pressure is reduced), ctr pressure increases in the opposite direction. When doing (when pressurized), Ptr will decrease. That is, an increase in blood pressure (change from diastolic blood pressure to systolic blood pressure) is equivalent to cuff pressure reduction, and a decrease in blood pressure (change from systolic blood pressure to diastolic blood pressure) is equivalent to cuff pressure increase.

Japanese Patent Publication No. 1-331370

K. Yamakoshi, H. Shimazu, M. Shibata, A. Kamiya, "New oscillometric method for indirect measurement of systolic and mean arterial pressure in the human finger. Part 1: model experiment", Medical & Biological Engineering & Computing, 1982, 20, p.307-313

  Thus, as shown in FIG. 15, in the conventional method of determining the control target value V0, the control target value is a control value for the change in arterial volume due to a decrease in blood pressure (change from systolic blood pressure to diastolic blood pressure). The change in arterial volume due to an increase in blood pressure (change from diastolic blood pressure to systolic blood pressure) was an excessive value. Therefore, the subject that systolic blood pressure cannot be measured correctly occurred. In addition, since the hysteresis of the mechanical characteristics is also present in the living tissue around the artery at the measurement site, it is natural that the influence is superimposed.

  The present invention has been made to solve the above-described problems, and one of its purposes is a blood pressure measurement device capable of more accurately measuring the blood pressure when the blood pressure rises and falls, and It is providing the control method of a blood-pressure measuring device.

  In order to achieve the above-described object, according to one aspect of the present invention, a blood pressure measurement device is a device for measuring blood pressure according to a volume compensation method, and when the blood pressure measurement device is attached to a blood pressure measurement site, A cuff that compresses the artery of the measurement site with liquid or gas pressure, a pressure-increasing / depressurizing unit for pressurizing and depressurizing the pressure inside the cuff, and a cuff pressure that is a pressure inside the cuff A pressure detection unit, a volume detection unit for detecting an arterial volume signal indicating the volume of the artery per unit length, and a control unit, wherein the control unit is detected by the volume detection unit Based on the arterial volume signal detected by the volume detection unit, the pressure increasing / decreasing unit is controlled to adjust the pressure of the cuff so that the volume indicated by the arterial volume signal matches a predetermined control target value. Pressure control means, and the pressure control As a result of adjustment by the stage, the cuff pressure detected by the pressure detection unit when the predetermined condition for determining that the volume coincides with the predetermined control target value is extracted as the blood pressure of the measurement subject Extracting means.

  The control unit is means for determining the predetermined control target value at the time of lowering blood pressure or at the time of increasing blood pressure, and when the control target value at the time of lowering blood pressure is determined, the cuff pressure is increased by the pressure increasing / decreasing unit. The average value of the arterial volume signal for one beat when the amplitude of the arterial volume change signal, which is an AC component of the arterial volume signal detected by the volume detector while being pressurized, becomes maximum when the blood pressure decreases While determining as the control target value, when determining the control target value at the time of increasing blood pressure, the artery which is an AC component of the arterial volume signal detected by the volume detecting unit while reducing the cuff pressure by the pressure increasing / decreasing unit 1st control target value determination means which determines the average value of the said arterial volume signal for 1 beat when the amplitude of a volume change signal becomes the maximum as the said blood pressure rise control target value is included.

  In the case where the control target value at the time of lowering blood pressure is determined by the first control target value determining means as the control target value at the time of lowering blood pressure, the pressure control means is the control target value at the time of increasing blood pressure. When the blood pressure rises, the volume indicated by the arterial volume signal detected by the volume detection unit matches the predetermined control target value determined by the first control target value determining means. And adjusting the pressure of the cuff.

  In the case where the control target value at the time of lowering blood pressure is determined by the first control target value determining means, the extracting means calculates the cuff pressure when the predetermined condition is satisfied at the time of lowering blood pressure as the blood pressure On the other hand, when the blood pressure rises, the cuff pressure when the predetermined condition is satisfied when the blood pressure rises is extracted as the blood pressure when the blood pressure rises.

  Preferably, when the control target value determined by the first control target value determining means is the blood pressure lowering control target value, the control unit further reduces the cuff pressure while reducing the cuff pressure. An average value of the arterial volume signal for one beat when the amplitude of the arterial volume change signal, which is an AC component of the arterial volume signal detected by the volume detector, becomes maximum is determined as the control target value at the time of increasing blood pressure. On the other hand, when the control target value at the time of increasing blood pressure is determined by the first control target value determining means, the volume detection unit detects the cuff pressure while increasing the cuff pressure. A second control target for determining an average value of the arterial volume signal for one beat when the amplitude of the arterial volume change signal, which is an AC component of the arterial volume signal, becomes maximum, as the control target value at the time of lowering blood pressure. Value determination means No.

  If the pressure control means determines the predetermined control target value as the predetermined control target value by the first control target value determination means or the second control target value determination means, When the control target value is when the blood pressure rises when descending, the volume indicated by the arterial volume signal detected by the volume detection unit when the blood pressure rises is the first control target value determining means or the first control target value determining means. The pressure of the cuff is adjusted so as to coincide with the predetermined control target value determined by the second control target value determining means.

  If the extraction target is the control target value at the time of lowering the blood pressure that is determined by the first control target value determining unit or the second control target value determining unit, While the cuff pressure when the blood pressure is satisfied is extracted as the blood pressure at the time of lowering the blood pressure, if the control target value is when the blood pressure is increased, the cuff pressure when the predetermined condition is satisfied when the blood pressure is increased is increased. Extracted as time blood pressure.

  More preferably, the control unit further detects a rising point at which the volume indicated by the arterial volume signal detected by the volume detection unit starts to increase and a falling point from which the decrease starts. Point detection means is included.

  The pressure control means is indicated by the arterial volume signal detected by the volume detection unit at the time of rising from when the rising point is detected by the change point detecting means until the falling point is detected. While adjusting the pressure of the cuff so that the volume coincides with the control target value at the time of increasing blood pressure, the volume at the time of falling from when the falling point is detected until the rising point is detected is The pressure of the cuff is adjusted so that the volume indicated by the arterial volume signal detected by the detection unit coincides with the blood pressure lowering control target value.

  Further preferably, the pressure control means is configured so that the volume indicated by the arterial volume signal detected by the volume detection unit coincides with the control target value at the time of blood pressure increase during the first period. On the other hand, in the second period different from the first period, the volume indicated by the arterial volume signal detected by the volume detection unit matches the control target value at the time of lowering blood pressure. And adjusting the pressure of the cuff.

  Preferably, the control unit is further configured to detect the pressure detecting unit when the blood pressure lowering control target value or the blood pressure increasing control target value is determined by the first control target value determining unit. When the control target value at the time of lowering blood pressure is determined by the first cuff pressure specifying means for specifying one cuff pressure and the first control target value determining means, The second cuff pressure detected by the pressure detection unit is specified when the amplitude of the arterial volume change signal, which is an AC component of the arterial volume signal detected by the volume detection unit, is maximized while reducing the pressure. On the other hand, when the control target value at the time of increasing blood pressure is determined by the first control target value determining means, the pressure is detected by the volume detecting unit while increasing the cuff pressure by the pressure increasing / decreasing unit. Of the arterial volume signal Second cuff pressure specifying means for specifying a second cuff pressure detected by the pressure detection unit when the amplitude of the arterial volume change signal, which is a flow component, becomes maximum, and the first cuff pressure Correction value calculating means for calculating a difference between the first cuff pressure specified by the specifying means and the second cuff pressure specified by the second cuff pressure specifying means as a correction value.

  Whether the pressure control means is determined as the predetermined control target value by the first control target value determination means is either the blood pressure lowering control target value or the blood pressure rising control target value, The pressure of the cuff is adjusted so that the volume indicated by the arterial volume signal detected by the volume detection unit coincides with the predetermined control target value determined by the first control target value determining means. To do.

  The extraction means further determines the cuff pressure when the predetermined condition is satisfied when the blood pressure increases when the first control target value determination means determines the control target value when the blood pressure decreases. While the value corrected by the correction value calculated by the correction value calculation means is extracted as the blood pressure at the time of blood pressure increase, if it is the control target value at the time of blood pressure increase, the predetermined condition is satisfied at the time of blood pressure decrease A value obtained by correcting the cuff pressure at the time with the correction value calculated by the correction value calculation means is extracted as a blood pressure at the time of lowering the blood pressure.

  According to another aspect of the present invention, a control method for controlling a blood pressure measurement device is a control method for a blood pressure measurement device for measuring blood pressure according to a volume compensation method. The blood pressure measurement device includes a cuff that compresses an artery of the measurement site with the pressure of an internal liquid or gas when the blood pressure measurement device is attached to the blood pressure measurement site, and a pressure increase / decrease for increasing and reducing the pressure inside the cuff A pressure detection unit for detecting a cuff pressure that is a pressure inside the cuff, a volume detection unit for detecting an arterial volume signal indicating the volume of the artery per unit length, and a control unit Have.

  The control method of the blood pressure measuring device is a step in which the control unit determines a control target value at the time of lowering blood pressure or at the time of increasing blood pressure. The average value of the arterial volume signal for one beat when the amplitude of the arterial volume change signal, which is the alternating current component of the arterial volume signal detected by the volume detector while increasing the cuff pressure, is When determining the control target value at the time of lowering blood pressure while determining the control target value at the time of increasing blood pressure, the AC component of the arterial volume signal detected by the volume detecting unit while reducing the cuff pressure by the pressure increasing / decreasing unit Determining the average value of the arterial volume signal for one beat when the amplitude of the arterial volume change signal is the maximum as the control target value at the time of increasing blood pressure, and determining the control at the time of decreasing blood pressure Target value If the blood pressure rises, the volume indicated by the arterial volume signal detected by the volume detection unit when the blood pressure rises is the blood pressure rise control target value. Or, based on the arterial volume signal detected by the volume detection unit so as to coincide with the control target value at the time of increasing blood pressure, the step of controlling the pressure increasing / decreasing unit to adjust the pressure of the cuff is determined. If the blood pressure lowering control target value is the blood pressure lowering control target value, the volume detected by the pressure detection unit when the condition for determining that the volume coincides with the blood pressure lowering control target value is met. While the cuff pressure is extracted as the blood pressure when the blood pressure of the person to be measured is decreased, if the control target value is when the blood pressure increases, it is determined that the volume coincides with the control target value when the blood pressure increases. The cuff pressure detected by said pressure detection portion when filled with the condition, and extracting a blood pressure when blood pressure of the subject.

  According to the present invention, when the control target value at the time of lowering blood pressure is determined by the blood pressure measurement device, the artery that is the AC component of the arterial volume signal detected by the volume detection unit while increasing the cuff pressure by the pressure increasing / decreasing unit. When the mean value of the arterial volume signal for one beat when the amplitude of the volume change signal is maximized is determined as the control target value at the time of lowering the blood pressure, The mean value of the arterial volume signal for one beat when the amplitude of the arterial volume change signal, which is the alternating current component of the arterial volume signal detected by the volume detector while reducing the cuff pressure, is controlled when the blood pressure rises. It is determined as a target value. When the control target value at the time of lowering blood pressure is determined, the arterial volume signal detected by the volume detection unit is detected at the time of lowering blood pressure. The volume shown is determined If the cuff pressure is adjusted to match the control target value and the determined control target value at the time of lowering blood pressure is determined, a predetermined value for determining that the volume matches the control target value at the time of lowering blood pressure. While the cuff pressure when the condition is satisfied is extracted as the blood pressure when the blood pressure decreases, the cuff pressure when the predetermined condition is satisfied when the blood pressure increases is the blood pressure when the blood pressure increases. Extracted as blood pressure.

  For this reason, the blood pressure measurement device measures the blood pressure when the blood pressure decreases with the control target value determined at the time of pressurization, and measures the blood pressure when the blood pressure increases with the control target value determined when the pressure is reduced. As a result, since it is possible to reduce the influence of mechanical hysteresis of the artery and the surrounding living tissue, the blood pressure measurement device capable of more accurately measuring the blood pressure when the blood pressure rises and falls, and the blood pressure A method for controlling the measuring apparatus can be provided.

1 is an external perspective view of an electronic blood pressure monitor according to an embodiment of the present invention. It is a figure showing the concept which controls the cuff pressure for the blood pressure measurement in the electronic blood pressure monitor which concerns on embodiment of this invention. It is a block diagram showing the hardware constitutions of the electronic blood pressure monitor which concerns on embodiment of this invention. It is a flowchart which shows the flow of the blood-pressure measurement process in the 1st Embodiment of this invention. It is a flowchart which shows the flow of the control target value detection process in the 1st Embodiment of this invention. It is a graph for demonstrating the method to determine a control target value in embodiment of this invention. It is a graph which shows the change of the cuff pressure and arterial volume signal at the time of control target value determination in the embodiment of the present invention, and blood pressure measurement. It is a flowchart which shows the flow of a part of blood pressure measurement process in the modification of the 1st Embodiment of this invention. It is a flowchart which shows the flow of the blood-pressure measurement process in the 2nd Embodiment of this invention. It is a flowchart which shows the flow of the control target value detection process in the 2nd Embodiment of this invention. It is a flowchart which shows the one part flow of the blood-pressure measurement process in the modification of the 2nd Embodiment of this invention. It is a graph which shows the mechanical characteristic of an artery. It is a graph which shows the hysteresis of an artery. It is a figure which shows a blood pressure waveform. It is a graph which shows the mechanical characteristic of the artery which considered the hysteresis.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the same or corresponding parts in the drawings are denoted by the same reference numerals and description thereof will not be repeated.

  The electronic sphygmomanometer 1 according to the present embodiment continuously measures blood pressure by the volume compensation method. The electronic sphygmomanometer 1 applies an external pressure to the artery by a cuff from outside the living body, and performs servo control using the determined optimum servo gain so that the external pressure, that is, the cuff pressure, and the intra-arterial pressure, that is, blood pressure are always balanced. In other words, the electronic sphygmomanometer 1 finely adjusts the cuff pressure so that the arterial wall is maintained in an unloaded state, and measures the cuff pressure at that time (unloaded state), whereby the minimum blood pressure and the maximum blood pressure, or Measure blood pressure continuously.

[First Embodiment]
FIG. 1 is an external perspective view of an electronic sphygmomanometer 1 according to an embodiment of the present invention. Referring to FIG. 1, an electronic sphygmomanometer 1 includes a main body 10 and a cuff 20 that can be wound around the limb of a person to be measured. The main body 10 is attached to the cuff 20. On the surface of the main body unit 10, a display unit 40 made of, for example, liquid crystal and an operation unit 41 for receiving instructions from a user (a person to be measured) are arranged. The operation unit 41 includes a plurality of switches.

  In the present embodiment, “limbs” represent an upper limb and a lower limb. That is, the limb includes a part from the wrist to the base of the arm and a part from the ankle to the base of the foot. In the following description, it is assumed that the cuff 20 is attached to the wrist of the measurement subject.

  The electronic sphygmomanometer 1 according to the present embodiment will be described by taking an example in which the main body 10 is attached to the cuff 20 as shown in FIG. The main body 10 and the cuff 20 may be connected by an air tube (air tube 31 in FIG. 3 described later).

  FIG. 2 is a diagram showing the concept of controlling the cuff pressure for blood pressure measurement in electronic blood pressure monitor 1 according to the embodiment of the present invention. FIG. 2 shows a state where the cuff 20 is attached to the wrist 200 of the measurement subject.

  Referring to FIG. 2, a cuff pressure adjusting mechanism including a pump 51 and an exhaust valve (hereinafter simply referred to as “valve”) 52 is disposed in the main body 10.

  The air system 30 including the pump 51, the valve 52, and the pressure sensor 32 for detecting the pressure (cuff pressure) in the air bag 21 is connected to the air bag 21 contained in the cuff 20 via the air tube 31. Connected.

  Inside the air bladder 21, a light emitting element 71 and a light receiving element 72 are arranged at a predetermined interval. In the present embodiment, the light emitting element 71 and the light receiving element 72 are arranged along the circumference of the wrist 200 when the cuff 20 is attached. However, the present invention is not limited to such an arrangement example.

  In addition, although the cuff 20 includes the air bag 21, the fluid supplied to the cuff 20 is not limited to air, and may be a liquid or a gel, for example. Or it is not limited to fluid, Uniform microparticles, such as a microbead, may be sufficient.

  FIG. 3 is a block diagram showing a hardware configuration of electronic blood pressure monitor 1 according to the embodiment of the present invention. Referring to FIG. 3, cuff 20 of electronic sphygmomanometer 1 includes air bag 21 and arterial volume sensor 70.

  The arterial volume sensor 70 is a sensor for detecting the volume of the artery at the blood pressure measurement site of the measurement subject, and includes the above-described light emitting element 71 (for example, light emitting diode) and light receiving element 72 (for example, phototransistor). It is comprised by the photoelectric sensor which has. The light emitting element 71 emits light to the artery, and the light receiving element 72 receives the transmitted light or reflected light of the artery irradiated by the light emitting element 71.

  The arterial volume sensor 70 may be any sensor that can detect the volume of the artery, and may detect the volume of the artery using an impedance sensor (impedance plethysmograph). In that case, instead of the light emitting element 71 and the light receiving element 72, a plurality of electrodes (an electrode pair for applying a current and an electrode pair for detecting a voltage) for detecting the impedance of a site including an artery are included.

  In addition to the display unit 40 and the operation unit 41 described above, the main unit 10 centrally controls each unit and performs various arithmetic processes, and a program that causes the CPU 100 to perform predetermined operations. And a memory unit 42 for storing various data, a nonvolatile memory for storing measured blood pressure data, for example, a flash memory 43, a power source 44 for supplying power to each unit via the CPU 100, and a current And a timer 45 for measuring time and outputting time-measured data to the CPU 100.

  The operation unit 41 includes a power switch 41A that receives an input of an instruction for turning on or off the power supply, a measurement switch 41B that receives an instruction to start measurement, a stop switch 41C that receives an instruction to stop measurement, and a flash It has a memory switch 41D for receiving an instruction to read information such as blood pressure recorded in the memory 43, and an ID switch 41E operated to input ID (Identification) information for identifying the person to be measured.

  The main body 10 further includes the air system 30, the cuff pressure adjusting mechanism 50, the oscillation circuit 33, the light emitting element driving circuit 73, and the arterial volume detection circuit 74 described above.

  The adjustment mechanism 50 includes a pump drive circuit 53 and a valve drive circuit 54 in addition to the pump 51 and the valve 52.

  The pump 51 supplies air to the air bladder 21 in order to increase the cuff pressure. The valve 52 is opened and closed to exhaust or seal the air in the air bladder 21. The pump drive circuit 53 controls the drive of the pump 51 based on a control signal given from the CPU 100. The valve drive circuit 54 performs opening / closing control of the valve 52 based on a control signal given from the CPU 100.

  The light emitting element drive circuit 73 controls the light emission amount of the light emitting element 71 in accordance with a command signal from the CPU 100.

  The arterial volume detection circuit 74 is a volume pulse based on a transmitted light amount or a reflected light amount of light emitted from the light emitting element 71 and reaching the light receiving element 72 of light in an absorption band of hemoglobin contained in blood (red blood cells) flowing through the blood vessel. An arterial volume change signal PGac which is an alternating current component of a volume pulse wave signal obtained by processing the wave signal (arterial volume signal PGdc) and the volume pulse wave signal with an HPF (High-pass filter) circuit is output to the CPU 100. . For example, assuming that the filter constant of the HPF circuit is 0.6 Hz, a signal exceeding 0.6 Hz is an AC component.

  The pressure sensor 32 is a capacitance-type pressure sensor, and the capacitance value changes depending on the cuff pressure. The oscillation circuit 33 outputs an oscillation frequency signal corresponding to the capacitance value of the pressure sensor 32 to the CPU 100. The CPU 100 detects a pressure by converting a signal obtained from the oscillation circuit 33 into a pressure.

  FIG. 4 is a flowchart showing a blood pressure measurement process according to the first embodiment of the present invention. Referring to FIG. 4, first, CPU 100 waits for an input of an operation for pressing power switch 41A (step ST1).

  When power switch 41A is pressed, CPU 100 performs an initialization process (step ST2). Specifically, as initialization processing, the CPU 100 initializes a memory area used for this processing in the memory unit 42, exhausts air from the air bladder 21, and performs 0 mmHg correction of the pressure sensor 32.

  Next, the CPU 100 waits for an input of an operation for pressing the measurement switch 41B (step ST3). When measurement switch 41B is pressed, CPU 100 executes a control target value detection process (step ST4).

  FIG. 5 is a flowchart showing a flow of control target value detection processing in the first embodiment of the present invention. Referring to FIG. 5, first, CPU 100 initializes maximum value PGacmax 'and cuff pressure value Pc0' of the arterial volume change signal stored in memory unit 42 (step ST101). In the following processing, the maximum value PGacmax 'and the cuff pressure value Pc0' of the arterial volume change signal are updated as needed, and the values until final determination are provisional values.

  Next, the CPU 100 controls the valve drive circuit 54 to close the valve 52 (step ST102), and controls the pump drive circuit 53 to drive the pump 51, thereby increasing the cuff pressure (step ST103). At the stage of increasing the cuff pressure, the CPU 100 detects signals (arterial volume signal PGdc, arterial volume change signal PGac) from the arterial volume detection circuit 74 (step ST104).

  Next, the CPU 100 determines that the amplitude of one heartbeat period of the arterial volume change signal PGac detected in step ST104 is the maximum value PGacmax ′ of the amplitude of the arterial volume change signal PGac since the start of pressurization of the cuff pressure. It is determined whether it is larger (step ST105). When determining that the value is larger, the CPU 100 updates the maximum value PGacmax 'with the amplitude value at that time, and also updates the cuff pressure Pc0' at that time (step ST106).

  CPU 100 determines whether or not the cuff pressure has reached a predetermined pressure (step ST107). The predetermined pressure is a pressure sufficiently higher than the maximum blood pressure of the measurement subject, and is, for example, 200 mmHg. When determining that the predetermined pressure has not been reached, the CPU 100 returns the process to step ST103 and repeats the process up to step ST106.

  When determining that the cuff pressure has reached a predetermined pressure, the CPU 100 determines the maximum value PGacmax ′ of the amplitude of the arterial volume change signal, and averages the arterial volume signal PGdc of one heartbeat cycle when the maximum value PGacmax ′ is reached. The value is calculated as the control target value V0inf at the time of pressurization, and the cuff pressure Pc0 ′ at that time is determined as the control initial cuff pressure Pc0 (step ST108).

  FIG. 6 is a graph for explaining a method of determining a control target value in the embodiment of the present invention. Referring to FIG. 6, when the cuff pressure is increased, the difference between the intra-arterial pressure Pa (that is, blood pressure) and the cuff pressure Pc and the one heartbeat cycle are shown along the upper graph of the two graphs. The arterial volume V indicated by the average value of the arterial volume signal PGdc decreases. When the cuff pressure Pc becomes equal to the intra-arterial pressure Pa, the arterial volume V becomes V0inf, the mechanical compliance of the arteries becomes maximum, and the amplitude of the arterial volume change signal PGac due to blood pressure fluctuations becomes maximum.

  When the blood pressure, that is, the arterial pressure Pa, decreases with respect to the cuff pressure, it can be considered in the same manner as when the cuff pressure increases with respect to the arterial pressure Pa. That is, V0inf can be set as a control target value at the time of blood pressure reduction. When the blood pressure is decreased, the cuff pressure Pc is used as the blood pressure of the measurement subject every time the arterial volume constant control converges using the control target value V0inf (for example, every time the amplitude of the arterial volume change signal PGac becomes a predetermined threshold value or less). Can be measured.

  Returning to FIG. 5, the CPU 100 initializes the maximum value PGacmax ′ of the amplitude of the arterial volume change signal (step ST109). Next, the CPU 100 controls the valve drive circuit 54 to gradually adjust the opening and closing of the valve 52 to reduce the cuff pressure (step ST110). At the stage of reducing the cuff pressure, the CPU 100 detects signals (arterial volume signal PGdc, arterial volume change signal PGac) from the arterial volume detection circuit 74 (step ST111).

  Next, the CPU 100 determines that the amplitude of one heartbeat period of the arterial volume change signal PGac detected in step ST111 is from the maximum value PGacmax ′ of the amplitude of the arterial volume change signal PGac so far after the start of cuff pressure reduction. It is determined whether it is large (step ST112). When determining that the value is larger, the CPU 100 updates the maximum value PGacmax 'with the amplitude value at that time (step ST113).

  CPU 100 determines whether or not the cuff pressure has reached a predetermined pressure (step ST114). The predetermined pressure is a pressure sufficiently lower than the minimum blood pressure of the measurement subject, and is, for example, 30 mmHg. When determining that the predetermined pressure has not been reached, the CPU 100 returns the process to step ST110 and repeats the process up to step ST113.

  When determining that the cuff pressure has reached the predetermined pressure, the CPU 100 controls the valve drive circuit 54 to exhaust the cuff air to open the valve 52 (step ST115).

  Then, the CPU 100 determines the maximum value PGacmax ′ of the amplitude of the arterial volume change signal, and uses the average value of the arterial volume signal PGdc of one heart cycle when the maximum value PGacmax ′ is reached as the control target value V0def at the time of pressurization. Calculate (step ST116). Thereafter, the CPU 100 returns the process to be executed to the caller process of this process.

  Referring to FIG. 6 again, when the cuff pressure is reduced, the difference between the intra-arterial pressure Pa (that is, blood pressure) and the cuff pressure Pc and one heartbeat cycle are shown along the lower graph of the two graphs. The arterial volume V indicated by the average value of the arterial volume signal PGdc is increased. When the cuff pressure Pc becomes equal to the intra-arterial pressure Pa, the arterial volume V becomes V0def, the arterial mechanical compliance becomes maximum, and the amplitude of the arterial volume change signal PGac due to blood pressure fluctuation becomes maximum.

  When the blood pressure, that is, the arterial pressure Pa, increases with respect to the cuff pressure, it can be considered in the same manner as when the cuff pressure decreases with respect to the arterial pressure Pa. That is, V0def can be set as a control target value when blood pressure increases. When the blood pressure increases, the cuff pressure Pc is used as the blood pressure of the person to be measured every time the arterial volume constant control converges using the control target value V0def (for example, every time the amplitude of the arterial volume change signal PGac becomes a predetermined threshold value or less). Can be measured.

  FIG. 7 is a graph showing changes in cuff pressure and arterial volume signal when determining a control target value and measuring blood pressure in the embodiment of the present invention. Referring to FIG. 7, when the processing from step ST103 to step ST108 in FIG. 5 is executed (up to about 35 seconds after the power is turned on), the cuff pressure Pc is increased from about 30 mmHg to about 130 mmHg. Pressed. In response to this, the value of the arterial volume signal PGdc also increases while vibrating in accordance with the heartbeat cycle.

  When the amplitude of the arterial volume change signal PGac is maximized, that is, when the amplitude of the arterial volume signal PGdc is also maximized, the average value of the arterial volume signal PGdc of one heart cycle is the control target value V0inf when the blood pressure decreases. Is calculated as

  When the processing from step ST110 to step ST116 in FIG. 5 is executed (from about 35 seconds after the power is turned on to about 70 seconds), the cuff pressure Pc is from about 130 mmHg to about 30 mmHg. Depressurized. In response to this, the value of the arterial volume signal PGdc also decreases while vibrating in accordance with the heartbeat cycle.

  When the amplitude of the arterial volume change signal PGac is maximum, that is, when the amplitude of the arterial volume signal PGdc is also maximum, the average value of the arterial volume signal PGdc in one heart cycle is the control target value V0def when the blood pressure increases. Is calculated as

  Returning to FIG. 4, the CPU 100 sets the cuff pressure to the control initial cuff pressure Pc0 determined in step ST108 of FIG. 5 (step ST5).

  As the arterial volume constant control, the CPU 100 controls the pump driving circuit 53 and the valve driving circuit 54 so as to change the cuff pressure Pc so that the value of the arterial volume signal PGdc matches the control target value V0inf at the time of blood pressure reduction ( Step ST6).

  After performing arterial volume constant control for a predetermined time (for example, 10 msec), it is determined whether or not the amplitude of the arterial volume change signal PGac is equal to or smaller than a predetermined threshold (step ST7). If it is determined that the value is equal to or less than the predetermined threshold value, it means that the arterial volume constant control has converged. Therefore, if the cuff pressure Pc at that time is the lowest value within one heartbeat, the CPU 100 It determines as a blood pressure, and displays the determined minimum blood pressure value on the display part 40 (step ST8). The determined minimum blood pressure value may be stored in the flash memory 43.

  Then, CPU 100 determines whether or not a predetermined period (for example, 40 seconds) has elapsed since the start of blood pressure measurement (step ST9). When determining that it has not elapsed, the CPU 100 returns the process to be executed to the process of step ST6. In addition, the CPU 100 causes the display unit 40 to display the average value of the minimum blood pressure values measured during a predetermined period after the start of blood pressure measurement as the final minimum blood pressure value.

  On the other hand, when determining that a predetermined period has elapsed since the start of blood pressure measurement, the CPU 100 advances the process to be executed to the process of step ST10. As the arterial volume constant control, the CPU 100 controls the pump drive circuit 53 and the valve drive circuit 54 so as to change the cuff pressure Pc so that the value of the arterial volume signal PGdc matches the control target value V0def when blood pressure increases ( Step ST10).

  After performing arterial volume constant control for a predetermined time (for example, 10 msec), it is determined whether or not the amplitude of the arterial volume change signal PGac is equal to or smaller than a predetermined threshold (step ST11). When the predetermined threshold value or less is reached, it means that the arterial volume constant control has converged. Therefore, if the cuff pressure Pc at that time is the maximum value within one heartbeat, the CPU 100 determines the maximum blood pressure of the subject. The determined systolic blood pressure value is displayed on the display unit 40 (step ST12). The determined systolic blood pressure value may be stored in the flash memory 43.

  Then, CPU 100 determines whether or not a stop signal is input (turned on) by operating stop switch 41C (step ST13). When determining that the stop signal is not input (in the off state), the CPU 100 returns the process to be executed to the process of step ST6. In addition, the CPU 100 causes the display unit 40 to display the average value of the highest blood pressure values measured after a predetermined period has elapsed since the start of blood pressure measurement as the final highest blood pressure value.

  On the other hand, when determining that the stop signal has been input (turned on), the CPU 100 controls the valve drive circuit 54 to exhaust the cuff air to open the valve 52 (step ST14). Thereafter, the CPU 100 ends the blood pressure measurement process, and turns off the electronic sphygmomanometer 1.

  Referring to FIG. 7 again, when the processing from step ST6 to step ST9 in FIG. 4 is executed (from about 80 seconds after the power is turned on to about 120 seconds), the blood pressure is reduced. The arterial volume constant control is performed using the control target value V0inf. For this reason, the minimum blood pressure side is measured as a value close to the true minimum blood pressure.

  Further, when the processing from step ST10 to step ST13 in FIG. 4 is executed (after about 120 seconds after the power is turned on, the control target value V0def at the time of blood pressure increase is used to perform constant arterial volume control. For this reason, the systolic blood pressure is measured as a value close to the true systolic blood pressure.

  As described above, the electronic sphygmomanometer 1 according to the first embodiment performs the arterial volume constant control using the control target value V0inf at the time of blood pressure reduction determined at the time of increasing the cuff pressure. The minimum blood pressure is measured among the blood pressures, and the arterial volume constant control is performed using the control target value V0def at the time of blood pressure increase determined when the cuff pressure is reduced, and the blood pressure at the time of blood pressure increase is measured. . As a result, the influence of mechanical hysteresis on the artery and the surrounding living tissue can be reduced, so that the blood pressure when the blood pressure increases and when the blood pressure decreases can be measured more accurately.

  Further, in the first period (for example, a predetermined period since the measurement of blood pressure was started), the minimum blood pressure is measured among the blood pressures at the time of blood pressure decrease, and a second period (for example, a predetermined period) In the subsequent period), the highest blood pressure is measured among the blood pressures when the blood pressure increases. As a result, the minimum blood pressure and the maximum blood pressure can be measured more accurately.

[Modification of First Embodiment]
In the first embodiment, the case of measuring the minimum blood pressure and the maximum blood pressure has been described. In the modification of the first embodiment, a case where blood pressure is continuously measured will be described. The process from step ST6 to step ST13 of FIG. 4 differs between the first embodiment and the modification. For this reason, as description of the modification of 1st Embodiment, a different process is demonstrated and the overlapping description is not repeated.

  FIG. 8 is a flowchart showing a part of the blood pressure measurement process in the modification of the first embodiment of the present invention. Referring to FIG. 8, after step ST <b> 5 described in FIG. 4, CPU 100 determines whether or not the blood pressure is decreasing after the falling point of arterial volume signal PGdc is detected until the rising point is detected. Judgment is made (step ST21).

  When determining that the blood pressure is decreasing, the CPU 100 executes the same processing as in step ST6 and step ST7 of FIG. On the other hand, when it is determined that the blood pressure is not decreasing, that is, when the blood pressure is increasing, the same processing as step ST10 and step ST11 of FIG. 4 is executed.

  When it is determined in step ST7 or step ST11 that the amplitude of the arterial volume change signal PGac has become equal to or less than a predetermined threshold by the constant arterial volume control in step ST6 or step ST10, the CPU 100 determines the cuff pressure Pc at that time as It determines as a to-be-measured person's blood pressure, and displays the determined blood pressure value on the display part 40 (step ST22). The determined blood pressure value may be stored in the flash memory 43. Next, the CPU 100 executes the same process as step ST13 of FIG.

  As described above, the electronic sphygmomanometer 1 according to the modification of the first embodiment performs the arterial volume constant control using the control target value V0inf at the time of the blood pressure decrease determined when the cuff pressure is increased, and the blood pressure The blood pressure at the time of decrease is measured, and the control target value V0def at the time of blood pressure increase determined at the time of decreasing the cuff pressure is used to perform constant arterial volume control, and the blood pressure at the time of blood pressure increase is measured. As a result, the influence of mechanical hysteresis on the artery and the surrounding living tissue can be reduced, so that the blood pressure when the blood pressure increases and when the blood pressure decreases can be measured more accurately.

  In addition, by detecting the falling point and rising point of the arterial volume signal PGdc, the time from when the rising point is detected until the falling point is detected is when the blood pressure increases, and the blood pressure at the time when the blood pressure increases From the time when the falling point is measured until the rising point is detected, the blood pressure is decreased, and the blood pressure when the blood pressure is decreased is measured. As a result, the control target value can be switched more accurately, so that the blood pressure when the blood pressure increases and decreases can be measured more accurately.

[Second Embodiment]
In the first embodiment, the control target value V0inf at the time of blood pressure decrease determined at the time of increasing the cuff pressure is used to measure the blood pressure at the time of blood pressure decrease, and the blood pressure at the time of increasing blood pressure determined at the time of decreasing the cuff pressure The control target value V0def is used to measure the blood pressure when the blood pressure increases.

  In the second embodiment, the blood pressure measured using the control target value V0inf at the time of blood pressure reduction determined at the time of increasing the cuff pressure is used as the blood pressure of the measurement subject as it is at the time of blood pressure reduction. The increase is corrected by the difference between the cuff pressure when the control target value V0inf is determined when the cuff pressure is increased and the cuff pressure when the amplitude of the arterial volume change signal PGac is maximized when the cuff pressure is decreased. The blood pressure of the subject.

  FIG. 9 is a flowchart showing a blood pressure measurement process according to the second embodiment of the present invention. Referring to FIG. 9, the blood pressure measurement process in the second embodiment includes steps ST4 and ST10 to ST12 of the blood pressure measurement process in the first embodiment described in FIG. 'And steps ST15 to ST17 are changed. For this reason, a changed part is demonstrated here and the overlapping description is not repeated.

  When the measurement switch 41B is pressed in step ST3, the CPU 100 executes a control target value detection process (step ST4 ').

  FIG. 10 is a flowchart showing the flow of the control target value detection process in the second embodiment of the present invention. Referring to FIG. 5, the blood pressure measurement process in the second embodiment includes steps S109, ST113, and ST116 of the blood pressure measurement process in the first embodiment described in FIG. These steps are changed to step ST113 ′ and step ST117. For this reason, a changed part is demonstrated here and the overlapping description is not repeated.

  After step S108, as in step ST101, the CPU 100 initializes the maximum value PGacmax 'and the cuff pressure value Pc0' of the amplitude of the arterial volume change signal (step ST109 ').

  When determining in step ST112 that the amplitude of one heartbeat period of the arterial volume change signal PGac is larger than the maximum value PGacmax ′ of the amplitude of the arterial volume change signal PGac since the start of the cuff pressure reduction, the CPU 100 The maximum value PGacmax ′ is updated with the amplitude value at that time, and the cuff pressure Pc0 ′ at that time is also updated (step ST113 ′).

  After step ST115, the CPU 100 determines the maximum value PGacmax ′ of the amplitude of the arterial volume change signal, determines the cuff pressure Pc0 ′ when the maximum value PGacmax ′ is reached during decompression, and the pressurization determined in step ST106. The difference between the cuff pressure Pc0 when the amplitude of the arterial volume change signal is maximized and the cuff pressure Pc0 ′ during decompression is calculated as a correction value (step ST117).

  Returning to FIG. 9, when it is determined that a predetermined period has elapsed since the start of the measurement of the minimum blood pressure, the CPU 100 performs control when the value of the arterial volume signal PGdc is a blood pressure decrease, as in arterial volume constant control, as in step ST6. The pump drive circuit 53 and the valve drive circuit 54 are controlled to change the cuff pressure Pc so as to coincide with the target value V0inf (step ST15).

  After performing arterial volume constant control for a predetermined time (for example, 10 msec), it is determined whether or not the amplitude of the arterial volume change signal PGac is equal to or smaller than a predetermined threshold (step ST16). If it is determined that the value is equal to or less than the predetermined threshold, it means that the arterial volume constant control has converged. Therefore, if the cuff pressure Pc at that time is the highest value within one heartbeat, The sum of the correction values calculated in step ST117 of FIG. 10 is determined as the measurement subject's systolic blood pressure, and the determined systolic blood pressure value is displayed on the display unit 40 (step ST17). The determined systolic blood pressure value may be stored in the flash memory 43.

  Thereafter, CPU 100 executes the same processing as step ST13 and step ST14 in FIG. 4 (step ST13, step ST14). In addition, the CPU 100 causes the display unit 40 to display the average value of the highest blood pressure values measured after a predetermined period has elapsed since the start of blood pressure measurement as the final highest blood pressure value.

  As described above, by the electronic sphygmomanometer 1 according to the second embodiment, when the blood pressure is reduced, the arterial volume constant control is performed using the control target value V0inf at the time of the blood pressure reduction determined when the cuff pressure is increased. Among the measured blood pressures at the time of blood pressure decrease, the minimum blood pressure is directly used as the minimum blood pressure of the measurement subject, and when the blood pressure increases, the control target value V0inf at the time of blood pressure decrease determined when the cuff pressure is increased is The arterial volume constant control is performed, and the maximum blood pressure among the measured blood pressures when increasing the blood pressure is the cuff pressure when the control target value V0inf is determined when the cuff pressure is increased and the artery when the cuff pressure is reduced Correction is made by the difference from the cuff pressure when the amplitude of the volume change signal PGac is maximum, and the maximum blood pressure of the subject is obtained. As a result, the influence of mechanical hysteresis on the artery and the surrounding living tissue can be reduced, so that the blood pressure when the blood pressure increases and when the blood pressure decreases can be measured more accurately.

  Further, in the first period (for example, a predetermined period since the measurement of blood pressure was started), the minimum blood pressure is measured among the blood pressures at the time of blood pressure decrease, and a second period (for example, a predetermined period of time) different from the first period is measured. In the subsequent period), the highest blood pressure is measured among the blood pressures when the blood pressure increases. As a result, the minimum blood pressure and the maximum blood pressure can be measured more accurately.

[Modification of Second Embodiment]
In the second embodiment, the case of measuring the minimum blood pressure and the maximum blood pressure has been described. In the modification of the second embodiment, a case where blood pressure is continuously measured will be described. The process from step ST6 to step ST13 of FIG. 9 differs between the second embodiment and the modification. For this reason, as description of the modification of 2nd Embodiment, a different process is demonstrated and the overlapping description is not repeated.

  FIG. 11 is a flowchart showing a part of the blood pressure measurement process in the modification of the second embodiment of the present invention. Referring to FIG. 11, after step ST <b> 5 described in FIG. 9, CPU 100 executes a process similar to steps ST <b> 6 and ST <b> 7 in FIG. 9.

  If it is determined in step ST7 that the amplitude of the arterial volume change signal PGac has become equal to or smaller than a predetermined threshold, the CPU 100 is in the process of lowering blood pressure from when the falling point of the arterial volume signal PGdc is detected until the rising point is detected. It is determined whether or not there is (step ST23).

  When determining that the blood pressure is decreasing, the CPU 100 determines the cuff pressure Pc at that time as the blood pressure of the person to be measured, and displays the determined blood pressure value on the display unit 40 (step ST24). The determined blood pressure value may be stored in the flash memory 43. Thereafter, the process to be executed is advanced to the process of step ST13.

  On the other hand, when it is determined that the blood pressure is not decreasing, that is, when the blood pressure is increasing, the CPU 100 adds the correction value calculated in step ST117 of FIG. 10 to the cuff pressure Pc at that time to be measured. The determined blood pressure value is displayed on the display unit 40 (step ST25). The determined blood pressure value may be stored in the flash memory 43. Thereafter, the process to be executed is advanced to the process of step ST13. In step ST13, the same process as step ST13 of FIG. 4 is executed.

  As described above, the electronic sphygmomanometer 1 according to the modification of the second embodiment uses the control target value V0inf at the time of blood pressure reduction determined when the cuff pressure is increased to reduce the arterial volume at the time of blood pressure reduction. Control is performed, and the measured blood pressure when the blood pressure is decreased is directly used as the blood pressure of the measurement subject. When the blood pressure increases, the control target value V0inf when the blood pressure decreases determined when the cuff pressure is increased is used. The arterial volume constant control is performed and the measured blood pressure when the blood pressure increases is the cuff pressure when the control target value V0inf is determined when the cuff pressure is increased and the amplitude of the arterial volume change signal PGac when the cuff pressure is reduced Is corrected by the difference from the cuff pressure at which the pressure becomes maximum, and is taken as the blood pressure of the subject. As a result, the influence of mechanical hysteresis on the artery and the surrounding living tissue can be reduced, so that the blood pressure when the blood pressure increases and when the blood pressure decreases can be measured more accurately.

  In addition, by detecting the falling point and rising point of the arterial volume signal PGdc, the time from when the rising point is detected until the falling point is detected is when the blood pressure increases, and the blood pressure at the time when the blood pressure increases From the time when the falling point is measured until the rising point is detected, the blood pressure is decreased, and the blood pressure when the blood pressure is decreased is measured. As a result, the control target value can be switched more accurately, so that the blood pressure when the blood pressure increases and decreases can be measured more accurately.

Next, a modification of the above-described embodiment will be described.
(1) In the above-described second embodiment and its modifications, the blood pressure measured using the control target value V0inf at the time of blood pressure reduction determined at the time of increasing the cuff pressure is expressed as The blood pressure of the measurement subject is used as it is, and when the blood pressure increases, the cuff pressure when the control target value V0inf is determined when the cuff pressure is increased and when the amplitude of the arterial volume change signal is maximized when the cuff pressure is reduced The blood pressure of the measurement subject was corrected by the difference from the cuff pressure.

  However, the present invention is not limited to this, and the blood pressure measured using the control target value V0def at the time of blood pressure increase determined when the cuff pressure is reduced is used as the blood pressure of the measurement subject as it is when the blood pressure increases, and when the blood pressure decreases Is measured by correcting the difference between the cuff pressure when the control target value V0def is determined when the cuff pressure is reduced and the cuff pressure when the amplitude of the arterial volume change signal is maximized when the cuff pressure is increased. The blood pressure of the person may be used.

  (2) 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.

1 Electronic Blood Pressure Monitor, 10 Main Body, 20 Cuff, 21 Air Bag, 30 Air System, 31 Air Tube, 32 Pressure Sensor, 33 Oscillator Circuit, 40 Display Unit, 41 Operation Unit, 41A
Power switch, 41B Measurement switch, 41C Stop switch, 41D Memory switch, 41E ID switch, 42 Memory unit, 43 Flash memory, 44 Power supply, 45 Timer, 50 Adjustment mechanism, 51 Pump, 52 Valve, 53 Pump drive circuit, 54 Valve Drive circuit, 70 Arterial volume sensor, 71 Light emitting element, 72 Light receiving element, 73 Light emitting element drive circuit, 74 Arterial volume detection circuit, 100 CPU.

Claims (6)

A cuff that compresses the artery of the measurement site with the pressure of the internal liquid or gas when attached to the measurement site of blood pressure, a pressurization / decompression unit for pressurizing and depressurizing the pressure inside the cuff, and the cuff A pressure detection unit for detecting a cuff pressure that is an internal pressure of the gas sensor, a volume detection unit for detecting an arterial volume signal indicating the volume of the artery per unit length, and a control unit, and the control Based on the arterial volume signal detected by the volume detection unit such that the volume indicated by the arterial volume signal detected by the volume detection unit matches a predetermined control target value. A pressure control means for adjusting the pressure of the cuff by controlling the pressure reducing section, and a result of adjustment by the pressure control means, when a predetermined condition for determining that the volume coincides with the predetermined control target value is satisfied Of the pressure detector The cuff pressure that is, including extraction means for extracting as a blood pressure of the subject, a blood pressure measuring device for measuring blood pressure in accordance with the volume compensation method,
The control unit further includes:
A means for determining the predetermined control target value at the time of lowering blood pressure or at the time of increasing blood pressure. When determining the control target value at the time of lowering blood pressure, the volume detection is performed while increasing the cuff pressure by the pressure increasing / decreasing unit. While determining an average value of the arterial volume signal for one beat when the amplitude of the arterial volume change signal, which is an AC component of the arterial volume signal detected by the unit, becomes maximum, as the control target value at the time of lowering blood pressure When determining the control target value at the time of increasing blood pressure, the amplitude of the arterial volume change signal, which is an AC component of the arterial volume signal detected by the volume detecting unit while reducing the cuff pressure by the pressure increasing / decreasing unit, is maximized. A first control target value determining means for determining an average value of the arterial volume signal for one beat when the blood pressure rises as the control target value at the time of increasing blood pressure;
In the case where the control target value at the time of lowering blood pressure is determined by the first control target value determining means as the control target value at the time of lowering blood pressure, the pressure control means is the control target value at the time of increasing blood pressure. When the blood pressure rises, the volume indicated by the arterial volume signal detected by the volume detection unit matches the predetermined control target value determined by the first control target value determining means. And adjust the cuff pressure,
In the case where the control target value at the time of lowering blood pressure is determined by the first control target value determining means, the extracting means calculates the cuff pressure when the predetermined condition is satisfied at the time of lowering blood pressure as the blood pressure A blood pressure measurement device that extracts the cuff pressure when the predetermined condition is satisfied when the blood pressure rises as the blood pressure when the blood pressure rises, while extracting the blood pressure when the blood pressure rises as the blood pressure when the blood pressure rises . The control unit further includes:
When the control target value at the time of lowering blood pressure is determined by the first control target value determining means, the arterial volume detected by the volume detecting unit while reducing the cuff pressure by the pressure increasing / decreasing unit While determining the average value of the arterial volume signal for one beat when the amplitude of the arterial volume change signal, which is the AC component of the signal, is maximum, as the blood pressure increase control target value, the first control target value When the blood pressure increase control target value is determined by the determining means, the AC component of the arterial volume signal detected by the volume detection unit while increasing the cuff pressure by the pressure increasing / decreasing unit A second control target value determining means for determining, as the blood pressure lowering control target value, an average value of the arterial volume signal for one beat when the amplitude of the arterial volume change signal is maximized;
If the pressure control means determines the predetermined control target value as the predetermined control target value by the first control target value determination means or the second control target value determination means, When the control target value is when the blood pressure rises when descending, the volume indicated by the arterial volume signal detected by the volume detection unit when the blood pressure rises is the first control target value determining means or the first control target value determining means. Adjusting the pressure of the cuff so as to coincide with the predetermined control target value determined by the control target value determination means of the second control,
If the extraction target is the control target value at the time of lowering the blood pressure that is determined by the first control target value determining unit or the second control target value determining unit, While the cuff pressure when the blood pressure is satisfied is extracted as the blood pressure at the time of lowering the blood pressure, if the control target value is when the blood pressure is increased, the cuff pressure when the predetermined condition is satisfied when the blood pressure is increased is increased. The blood pressure measurement device according to claim 1, wherein the blood pressure measurement device extracts the blood pressure as time. The control unit further includes:
The volume indicated by the arterial volume signal detected by the volume detection unit includes a change point detection means for detecting a rising point at which an increase starts and a falling point at which a decrease starts.
The pressure control means is indicated by the arterial volume signal detected by the volume detection unit at the time of rising from when the rising point is detected by the change point detecting means until the falling point is detected. While adjusting the pressure of the cuff so that the volume coincides with the control target value at the time of increasing blood pressure, the volume at the time of falling from when the falling point is detected until the rising point is detected is The blood pressure measurement device according to claim 2, wherein the pressure of the cuff is adjusted so that the volume indicated by the arterial volume signal detected by a detection unit coincides with the control target value at the time of lowering blood pressure.   In the first period, the pressure control means adjusts the pressure of the cuff so that the volume indicated by the arterial volume signal detected by the volume detection unit coincides with the control target value at the time of increasing blood pressure. On the other hand, in the second period different from the first period, the cuff is set so that the volume indicated by the arterial volume signal detected by the volume detection unit matches the control target value at the time of lowering blood pressure. The blood pressure measurement device according to claim 2, wherein the blood pressure is adjusted. The control unit further includes:
A first cuff pressure that is detected by the pressure detector when the blood pressure lowering control target value or the blood pressure rising control target value is determined by the first control target value determining means; Cuff pressure identification means;
When the control target value at the time of lowering blood pressure is determined by the first control target value determining means, the arterial volume detected by the volume detecting unit while reducing the cuff pressure by the pressure increasing / decreasing unit The second cuff pressure detected by the pressure detector when the amplitude of the arterial volume change signal, which is an AC component of the signal, becomes maximum, is determined by the first control target value determining means. Is the control target value at the time of blood pressure increase, the amplitude of the arterial volume change signal, which is an AC component of the arterial volume signal detected by the volume detecting unit while increasing the cuff pressure by the pressure increasing / decreasing unit, is Second cuff pressure specifying means for specifying the second cuff pressure detected by the pressure detection unit when the maximum time is reached;
Correction value calculation for calculating a difference between the first cuff pressure specified by the first cuff pressure specifying means and the second cuff pressure specified by the second cuff pressure specifying means as a correction value Means,
Whether the pressure control means is determined as the predetermined control target value by the first control target value determination means is either the blood pressure lowering control target value or the blood pressure rising control target value, The pressure of the cuff is adjusted so that the volume indicated by the arterial volume signal detected by the volume detection unit coincides with the predetermined control target value determined by the first control target value determining means. And
The extraction means further determines the cuff pressure when the predetermined condition is satisfied when the blood pressure increases when the first control target value determination means determines the control target value when the blood pressure decreases. While the value corrected by the correction value calculated by the correction value calculation means is extracted as the blood pressure at the time of blood pressure increase, if it is the control target value at the time of blood pressure increase, the predetermined condition is satisfied at the time of blood pressure decrease The blood pressure measurement device according to claim 1, wherein a value obtained by correcting the cuff pressure at the time with the correction value calculated by the correction value calculation means is extracted as a blood pressure at the time of lowering blood pressure. A cuff that compresses the artery of the measurement site with the pressure of the internal liquid or gas when attached to the measurement site of blood pressure, a pressurization / decompression unit for pressurizing and depressurizing the pressure inside the cuff, and the cuff A pressure detection unit for detecting a cuff pressure, which is an internal pressure of the tube, a volume detection unit for detecting an arterial volume signal indicating the volume of the artery per unit length, and a control unit. A control method for controlling a blood pressure measurement device for measuring blood pressure according to a method,
The control unit is
In the step of determining a control target value at the time of lowering blood pressure or at the time of increasing blood pressure, when the control target value at the time of lowering blood pressure is determined, the volume detecting unit detects the cuff pressure while increasing the cuff pressure. The mean value of the arterial volume signal for one beat when the amplitude of the arterial volume change signal, which is the AC component of the arterial volume signal, is maximized is determined as the control target value at the time of lowering blood pressure, while the blood pressure is increased When determining the time control target value, when the amplitude of the arterial volume change signal, which is an AC component of the arterial volume signal detected by the volume detecting unit while reducing the cuff pressure by the pressure increasing / decreasing unit, is maximized Determining an average value of the arterial volume signal for one beat as a control target value at the time of increasing blood pressure;
When the control target value at the time of lowering blood pressure is determined, it is indicated by the arterial volume signal detected by the volume detection unit at the time of lowering blood pressure, and when the control target value at the time of increasing blood pressure is increased, the blood pressure is increased. Control the pressure increasing / decreasing unit based on the arterial volume signal detected by the volume detecting unit so that the volume coincides with the determined blood pressure lowering control target value or the blood pressure rising control target value And adjusting the pressure of the cuff;
If the determined control target value at the time of lowering blood pressure is determined, it is detected by the pressure detection unit when the condition for determining that the volume coincides with the control target value at lowering blood pressure at the time of lowering blood pressure is detected. The cuff pressure is extracted as the blood pressure at the time when the blood pressure of the measurement subject is lowered. If the cuff pressure is the control target value at the time of increasing blood pressure, it is determined that the volume coincides with the control target value at the time of increasing blood pressure. Extracting the cuff pressure detected by the pressure detection unit when a condition for satisfying a condition for blood pressure when the blood pressure of the measurement subject is increased is included.

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