Electronic blood pressure monitor

Abstract

Electronic blood pressure monitor (1), which comprises: a first fluid bellows (13); a first adjusting unit (20) for injecting / ejecting a fluid into / from the first fluid bladder (13) at a variable speed; a sensor (23) for detecting an internal pressure of the first fluid bellows (13); a winding unit (10) for winding the first fluid bladder (13) around a measuring area of ​​a measuring person at a variable winding thickness; a second adjusting unit (30) for adjusting the winding thickness of the winding unit (10); and a control unit (40-42), wherein the control unit (40-42) executes: a first control process which outputs a first control signal to the first setting unit (20) so that a rate of change in the internal pressure and / or the fluid amount in the fluid bladder becomes a predetermined rate of change; a second control process which outputs a second control signal to the second setting unit (30) so that the winding thickness reaches a predetermined relationship with the rate of change in the internal pressure and / or fluid amount in the first fluid bladder (13) under the first control process; and a calculation process which calculates a blood pressure value of the measured person based on a change in the internal pressure of the first fluid bladder (13) detected under the first control process, wherein the control unit (40-42) sets the predetermined ratio to a previously set ratio or changes the predetermined ratio by using a previously set compensation formula corresponding to at least one of a circumferential length of the measurement area, an already measured blood pressure value of the measurement subject, a blood pressure value of the measurement subject estimated during inflation, a size of the first fluid bladder (13), and a maximum value of the pressure in the first fluid bladder (13).

Description

Technical area

[0001] This invention relates to electronic blood pressure monitors, and more particularly, it relates to electronic blood pressure monitors that automatically wrap a measuring band (cuff) containing an air bladder around a measuring area. Background of the state of the art

[0002] Blood pressure is an index to analyze circulatory diseases, and performing risk analysis based on blood pressure is effective for preventing cardiovascular-related conditions such as stroke, heart failure, and myocardial infarction.

[0003] Previously, diagnoses were made by measuring blood pressure (casual blood pressure) in medical settings, such as during hospital visits, health checkups, and so on. However, recent research has shown that blood pressure measured at home (home blood pressure) is more useful in diagnosing circulatory diseases than casual blood pressure. As a result, home blood pressure monitors have become widely available.

[0004] Many household blood pressure monitors employ oscillometric or microphone blood pressure measurement techniques. Oscillometric blood pressure measurement involves wrapping a measuring band (cuff) containing an air bladder around a measurement area, such as the upper arm. The internal pressure of the cuff (a cuff pressure) is increased to a predetermined pressure (e.g., 30 mmHg) below the systolic blood pressure. A change in artery volume is detected as a change in the pressure superimposed on the cuff pressure (a pressure pulse wave amplitude) while the cuff pressure is gradually or in steps reduced. Systolic blood pressure and diastolic blood pressure are determined based on changes in the pressure pulse wave amplitude. Furthermore, oscillometric technology allows blood pressure measurement by detecting a pressure pulse wave amplitude that occurs while the cuff pressure is increased.

[0005] Meanwhile, with the microphone technique, the cuff is wrapped around a measuring area, such as the upper arm, and the cuff pressure is increased to a predetermined pressure below the systolic blood pressure, in the same way as with the oscillometric technique. Subsequently, the Korotkoff sound produced by the artery is detected via a microphone mounted inside the cuff as the cuff pressure is gradually reduced. The cuff pressure when the Korotkoff sound is produced is taken as the systolic blood pressure, whereas the cuff pressure when the Korotkoff sound is weak or absent is taken as the diastolic blood pressure.

[0006] In either method, if the cuff of the sphygmomanometer is not properly wrapped around the measurement area, the cuff pressure is not sufficiently transmitted to the artery, resulting in a problem of a decrease in measurement accuracy. Accordingly, regarding a sphygmomanometer having a configuration that automatically wraps a cuff around a measurement site (hereinafter referred to as a "fully automatic arm sphygmomanometer"), the present applicants previously published a technique in JP-2005-230175A (Patent Literature 1) in which a winding member configured from a flexible member and a winding air bladder are arranged on the outside of a measurement air bladder for winding the measurement air bladder around the measurement site; by inflating the wrapping air bladder, the diameter of the winding member is reduced, thereby winding the measurement air bladder around the measurement area.

[0007] Furthermore, the present applicants have previously published a technique for improving the accuracy of oscillometric blood pressure measurement in JP 2009-279196A (Patent Literature 2); with this technique, the measurement accuracy is improved by reducing the offset in a detected pressure pulse wave amplitude by controlling an air discharge flow amount from a measuring air bladder per unit time in a proportional relationship to a speed of deflation of the measuring air bladder. Citation listPatent literature Patent Literature 1: JP 2005-230175A Patent Literature 2: JP 2009-279196A

[0008] US 7 153 270 B2 describes a blood pressure monitoring device for measuring blood pressure on the body of a living being. The device includes a device for securing to the body with two air sacs, wherein the inner air sac is arranged and configured to press against the body, and wherein the outer air sac is elastic, cylindrical, and radially variable to press the inner air sac against the body.

[0009] US 2004 / 0 064 055 A1 describes a device for assessing the degree of arteriosclerosis in a living being. It comprises a pulse wave detection device worn on one body part and a pressure device worn on another part to restrict blood flow. The device determines arteriosclerosis-related information by analyzing the peak points of the incident and reflected wave components of a pulse. Summary of the inventionTechnical problem

[0010] Occasionally, the cuff structure in a fully automatic arm blood pressure monitor is a dual structure, including a measuring air bladder that compresses an artery in a measuring area to perform blood pressure measurement, detects a change in the volume of the artery that occurs when the pressure is gradually increased or decreased as a change in the pressure within the air bladder, and calculates a blood pressure based on this pressure change, as described earlier, as well as a winding mechanism for winding the measuring air bladder around the measuring area. The flexible member (hereinafter "winding member") is provided between these two structures.

[0011] In the fully automatic arm blood pressure monitor, the air bladder is inflated by supplying air to it, and the measuring air bladder is wound around the measuring area using the winding member; then, the pulse wave amplitude is detected while the measuring air bladder is being inflated / deflated with air, and the systolic blood pressure and diastolic blood pressure are determined based on changes in the pressure pulse wave amplitude.

[0012] Accordingly, in this measuring method, the winding member will expand outward in the radial direction in the case where the pressure of the winding mechanism is lower than the pressure of the measuring air bladder, whereas the winding member will contract inward in the radial direction in the case where the pressure of the winding mechanism is higher than the pressure of the measuring air bladder. Accordingly, there is a problem in that the measuring air bladder will not properly establish the measuring range in pressure and the pressure pulse wave amplitude cannot be correctly detected. In addition, there is a problem in that if the winding member has moved inward or outward in the radial direction in this way, a false pulse wave may be generated by the resulting vibrations, which may affect the measurement accuracy.

[0013] In view of the above-mentioned problems that have been encountered, it is an object of the present invention to provide, particularly in an electronic blood pressure monitor that automatically winds a measuring band (cuff) including an air bladder around a measuring portion, an electronic blood pressure monitor that controls a measuring bladder pressure and a winding mechanism pressure so that the cuff is properly wound around the measuring portion. Solution to the problem

[0014] To achieve the above-mentioned object, according to one aspect of the present invention, an electronic blood pressure monitor includes a first fluid bladder, a first setting unit for injecting or ejecting a fluid into / from the first fluid bladder at a variable speed, a sensor for detecting an internal pressure of the first fluid bladder, a wrapping unit for wrapping the first fluid bladder around a measurement area of ​​a measured person at a variable wrapping thickness, a second setting unit for adjusting the wrapping thickness of the wrapping unit, and a control unit. The control unit executes a first control process that outputs a first control signal to the first setting unit so that a rate of change orspeed in the internal pressure and / or fluid amount in the first fluid bladder becomes a predetermined change speed, a second control process which outputs a second control signal to the second setting unit so that the winding strength reaches a predetermined ratio between the change speed in the internal pressure and / or fluid amount in the first fluid bladder under the first control process, and a calculation process which calculates a blood pressure value of the measured person based on a change in the internal pressure of the first fluid bladder detected under the first control process.

[0015] Preferably, the first control signal is set in advance so that the rate of change in the internal pressure in the first fluid bladder and the rate of change in the fluid amount in the first fluid bladder are in a proportional relationship, the second control signal is set in advance according to the first control signal so as to achieve the predetermined relationship, and the control unit performs forward control on the first control process and the second control process.

[0016] Preferably, the wrapping unit includes a second fluid bladder which is located further from the measuring portion than the first fluid bladder when worn on the measuring portion, the second setting unit includes a pump for injecting and / or a value for ejecting the fluid into / from the second fluid bladder at a variable speed, and the second control process includes a process for determining a drive voltage for the pump and / or the valve.

[0017] The control unit sets the predetermined ratio to a preset ratio or changes the predetermined ratio using a preset compensation formula according to at least one of a circumferential length of the measurement area, an already measured blood pressure value of the subject, a blood pressure value of the subject obtained during inflation, a size of the first fluid bladder, and a maximum value of the pressure in the first fluid bladder.

[0018] Further, it is preferable that the control unit determines the circumferential length of the measuring region and / or the dimension of the first fluid bladder based on a rate of change in the internal pressure of the first fluid bladder during inflation.

[0019] Furthermore, it is preferable that the control unit determines the blood pressure value of the person being measured by obtaining a previous measurement result.

[0020] Further, it is preferable that in the calculation process, the control unit calculates the blood pressure based on a change in the internal pressure in the first fluid bladder when the first fluid bladder is inflated under the first control process, and the control unit takes the blood pressure value calculated based on a change in the internal pressure in the first fluid bladder when the first fluid bladder is inflated as a blood pressure value of the subject used to determine the predetermined ratio.

[0021] Furthermore, it is preferable that the electronic blood pressure monitor further includes an input unit for accepting an input signal of at least one of a circumferential length of the measuring area, the already measured blood pressure value of the measured person, a dimension of the first fluid bladder, and a maximum value of the pressure in the first fluid bladder.

[0022] Furthermore, it is preferable that the electronic blood pressure measuring device further includes a readout unit for reading out from another device at least one of a circumferential length of the measuring area, the already measured blood pressure value of the person being measured, a dimension of the first fluid bladder and a maximum value of the pressure in the first fluid bladder.

[0023] It is preferable that the control unit changes the predetermined ratio to a predetermined ratio or changes the predetermined ratio by using a predetermined compensation formula at at least one of a time when the internal pressure of the first fluid bladder reaches a predetermined level, a time when the winding strength reaches a predetermined level, and a time when a predetermined amount of time has elapsed following a predetermined time point of a measuring process.

[0024] It is preferable that the control unit changes the predetermined ratio to a preset ratio or changes the predetermined ratio using a preset compensation formula according to a size of a pulse wave amplitude detected from the internal pressure of the first fluid bladder.

[0025] A control method according to another aspect of the present invention is a control method for an electronic blood pressure monitor having: a first fluid bladder, a first setting unit for injecting / ejecting a fluid into / from the first fluid bladder at a variable speed, a sensor for detecting an internal pressure of the first fluid bladder, and a wrapping unit for wrapping the first fluid bladder around a measurement area of ​​a measurement subject at a variable wrapping thickness, the control method including: a step of controlling the first setting unit so that a change speed in the internal pressure and / or fluid amount in the first fluid bladder becomes a predetermined change speed, a step of controlling a second setting unit,so that the wrapping strength reaches a predetermined ratio to the rate of change in the internal pressure and / or fluid amount in the first fluid bladder under the control in the step of controlling the first setting unit, wherein the predetermined ratio is set to a predetermined ratio or the predetermined ratio is changed by using a predetermined compensation formula corresponding to at least one of a circumferential length of the measurement area, an already measured blood pressure value of the measured person, a blood pressure value of the measured person estimated during inflation, a size of the first fluid bladder, and a maximum value of the pressure in the first fluid bladder, and a step of calculating a blood pressure value of the measured person based on a change in the internal pressure of the first fluid bladder detected under the control of the step of controlling the first setting unit. Advantageous effects of the invention

[0026] According to this invention, a cuff can be properly wrapped around a measuring area during measurement, and thus the measurement accuracy can be improved. Short description of the drawings Fig. 1 is a perspective view showing a specific example of an external appearance of a blood pressure monitor according to a first embodiment. Fig. Figure 2 is a schematic cross-sectional drawing showing the blood pressure monitor during blood pressure measurement. Fig. 3 is a cross-sectional view showing the internal structure of a measuring section. Fig. Figure 4 is a block diagram showing a specific example of the functional configuration of the blood pressure monitor. Fig. 5 is a flowchart illustrating a blood pressure measurement operation performed by the blood pressure meter according to the first embodiment. Fig. 6 is a diagram showing change rates in a decreasing rate of pressure in a measuring air bellows in the case where a driving voltage of a valve is kept constant, for each of the circumferential lengths of the measuring sections. Fig. 7 is a diagram illustrating the relationship between a driving voltage and a circumferential length, which is calculated by using a relationship expression between the circumferential length information and a pump / valve driving voltage. Fig. 8 is a diagram showing rates of change in a rate of reduction of a pressure in a measuring air bellows in the case where the circumferential length of the measuring area is the same. Fig. 9A is a graph showing a relationship between a pressure in the measuring air bladder and the decreasing speed in the blood pressure meter according to the first embodiment. Fig. 9B is a diagram illustrating a relationship between a pressure in the measuring air bladder and an air discharge amount in the blood pressure meter according to the first embodiment. Fig. 9C is a diagram illustrating a relationship between a pressure in the measuring air bladder and a pressure pulse wave amplitude value for a set volume change in the blood pressure meter according to the first embodiment. Fig. 10 is a diagram showing a relationship between internal pressure changes in a compression air bladder and the measuring air bladder. Fig. 11 is a graph showing a relationship between the internal pressure changes in the compression air bladder and the measuring air bladder. Fig. 12 is a diagram showing a specific example of a relationship between an upper arm circumference, which is a specific example of a circumferential length, and a predetermined ratio indicating a ratio of the internal pressures of the measuring air bladder and the compression air bladder. Fig. 13 is a diagram showing a specific example of a relationship between a maximum inflation value of the measuring air bladder and the previously set ratio, which indicates a ratio of the internal pressures of the measuring air bladder and the compressing air bladder. Fig. 14 is a diagram showing a specific example of a relationship between an upper arm circumference, a systolic blood pressure value, and a preset ratio indicating a ratio of the internal pressures of the measuring air bladder and the compressing air bladder. Fig. 15 is a diagram showing a plan view of a blood pressure monitor according to a second embodiment. Fig. 16 is a diagram illustrating the relationship between a change in a driving voltage to drive a wire take-up unit and a change in the internal pressure of the measuring air bladder which is compressed via a wire to compress a measuring area. Description of the embodiments

[0027] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following descriptions, identical reference numerals are added to identical components or structural elements. The names and functions thereof are also the same. First embodimentsDevice configuration

[0028] Fig. 1 is a perspective view showing a specific example of an external appearance of a blood pressure monitor (hereinafter referred to as a “blood pressure monitor”) 1 according to a first embodiment.

[0029] As in Fig. As shown in Figure 1, the blood pressure monitor 1 according to the present embodiment primarily includes a main body 2 placed on a table or the like, and a measuring section 5 into which an upper arm serving as a measuring portion is inserted. An operation unit 3 in which a power switch, a measuring switch, a stop switch, a user selection switch, and the like are arranged, a display unit 4, and an elbow rest are provided in an upper portion of the main body 2. Meanwhile, the measuring section 5 is fixed so that its angle can be varied relative to the main body 2, and includes a housing 60, which is a casing having an approximately cylindrical shape, as well as a body compression / stabilization unit contained in an inner peripheral surface of the housing 60. Note that, as shown in Fig. 1, in a normal use state, the body compression / stabilization unit contained in the inner peripheral surface of the housing 60 is not exposed and is covered by a cover 70.

[0030] Fig. Figure 2 is a schematic cross-sectional drawing showing the blood pressure device 1 during blood pressure measurement. As shown in Fig. As shown in Figure 2, during blood pressure measurement, an upper arm 100 is inserted into the housing 60, the elbow is placed on the indicated elbow support, and the measurement is instructed to start. The upper arm is compressed and stabilized by the indicated body compression / stabilization unit, and the blood pressure is measured.

[0031] The body compression / stabilization unit includes: an air bladder 13, which corresponds to a cuff and serves as a fluid bladder to compress the measurement area and to measure blood pressure; a winding member 10, which is placed on the outside of the air bladder 13 and serves as an approximately cylindrical flexible member capable of expanding and contracting in the radial direction; and an air bladder 8, which is placed on the outside of the winding member 10 and serves as a fluid bladder, which causes the winding member 10 to contract by expanding and compressing an outer peripheral surface of the winding member 10 in the inward direction, which stabilizes the air bladder 13 against the measurement area of ​​a body by pressing the air bladder 13 via the winding member 10 and the housing.

[0032] Fig. 3 is a cross-sectional view showing the internal structure of the measuring section 5. As in Fig. 3, in the measuring section 5, the air bellows 8 is provided on the inside of the housing 60 and expands / contracts, whereby a compression and stabilization air system 30 (see Fig. 4) is used, which will be mentioned later.

[0033] The winding member 10, which is configured from a plate-shaped member wound into an approximately cylindrical shape, is disposed on the inside of the air bellows 8 (i.e., the side toward the measurement area) and elastically deforms in the radial direction when an external force is applied thereto. The air bellows 13 is provided on the inside of the winding member 10 and expands / contracts, with a measurement air system 20 (see Fig. 4) which will be mentioned later.

[0034] Fig. 4 is a block diagram showing a specific example of the functional configuration of the blood pressure monitor 1.

[0035] As in Fig. As shown in Figure 4, the blood pressure monitor 1 includes the air bladder 13 and the air bladder 8, which are connected to the measurement air system 20 and the compression and stabilization air system 30, respectively. The air system 20 includes a pressure sensor 23 for measuring an internal pressure of the air bladder 13, a pump 21 for supplying / expelling air to / from the air bladder 13, and a valve 22, whereas the air system 30 includes a pressure sensor 33 for measuring an internal pressure of the air bladder 8, a pump 31 for supplying / expelling air to / from the air bladder 8, and a valve 32.

[0036] The air bellows 13 is connected to the pressure sensor 23 for measuring changes in the internal pressure of the air bellows 13, the pump 21 for injecting / expelling air into / from the air bellows 13, and the valve 22. The air bellows 8 is connected to the pressure sensor 33 for measuring changes in the internal pressure of the air bellows 8, the pump 31 for injecting / expelling air into / from the air bellows 8, and the valve 32.

[0037] The pressure sensors 23 and 33, the pumps 21 and 31, and the valves 22 and 32 are respectively connected to the oscillation circuits 28 and 38, the drive circuits 26 and 36, and the drive circuits 27 and 37; meanwhile, the oscillation circuits 28 and 38, the drive circuits 26 and 36, and the drive circuits 27 and 37 are all connected to a CPU (central processing unit) 40 to control the blood pressure monitor 1 as a whole.

[0038] In addition, the display unit 4, the operation unit 3, a memory 6 which stores programs executed by the CPU 40 and which serves as a work area when the programs are executed, a memory 7 which stores the measurement results and the like, and an external interface (I / F) 80 for connecting an external device and outputting / inputting data are connected to the CPU 40.

[0039] The CPU 40 includes: a first control unit 41 for controlling the pump 21 and the valve 22 by outputting control signals to the drive circuits 26 and 27; a second control unit 42 for controlling the pump 31 and the valve 32 by outputting control signals to the drive circuits 36 and 37; a calculation unit 43 for calculating a blood pressure value based on a pressure signal from the pressure sensor 23; and a display control unit 44 for executing control to display the measurement results and the like on the display unit 4. These are implemented in the CPU 40 by executing predetermined programs stored in the memory 6 based on operation signals input from the operation unit 3.

[0040] The driver circuits 26 and 36 drive the pumps 21 and 31, respectively, according to the control signals from the CPU 40. As a result, air is injected into the air bladders 13 and 8.

[0041] The drive circuits 27 and 37 drive the valves 22 and 32, respectively, according to control signals from the CPU 40. As a result, the valves 2 and 32 are opened / closed. In addition, the opening widths thereof (hereinafter referred to as an "opening") are also controlled, thereby controlling the discharge amount and discharge speed of the air in the air bladders 13 and 8.

[0042] The pressure sensors 23 and 33 are capacitance-type electrostatic pressure sensors, and their capacitance values ​​change as the internal pressures of the air bellows 13 and 8 change. The pressure sensors 23 and 33 are connected to the oscillation circuits 28 and 38, respectively. The oscillation circuits 28 and 38 convert the capacitance values ​​of the pressure sensors 23 and 33 into oscillation frequency signals based thereon and input those signals to the CPU 40.

[0043] The first control unit 41 and the second control unit 42 of the CPU 40 control the pumps 21 and 31 and the valves 22 and 32 by outputting control signals to the driver circuits 26 and 27 and the driver circuits 36 and 37. Meanwhile, the calculation unit 43 of the CPU 40 calculates a blood pressure value based on changes in the internal pressure of the air bladder 31 obtained from the pressure sensor 23. The display control unit 44 of the CPU 40 executes a process to display a measurement result on the display unit 4 and outputs data and a control signal to perform the display for the display unit 4. Furthermore, the CPU 40 executes a process to store the blood pressure value in the memory 7. Measuring operation

[0044] Fig. Fig. 5 is a flowchart illustrating a blood pressure measuring operation performed by the blood pressure meter 1 according to the first embodiment. The blood pressure measuring operation shown in the flowchart in Fig. 5 is an operation performed in the case where the CPU 40 calculates a blood pressure value based on changes in the internal pressure of the air bladder 13 when the air bladder 13 is inflated. This operation is started when the CPU 40 receives an operation signal as a result of the power switch in the operation unit 3 being pressed, and is implemented by the CPU 40 reading a program stored in the memory 6 and controlling the various units included in Fig. 4 are shown.

[0045] As in Fig. 5, after the initialization is first performed in step S11, the CPU 40 stands by until the user selection switch and the measurement switch are pressed.

[0046] Next, when the CPU 40 receives an operation signal resulting from the selection switch being pressed and then receives an operation signal resulting from the measurement switch being operated (YES in step S13 and YES in step S15), in step S17 the CPU 40 starts a winding operation, which is an operation to properly wind the air bladder 13 around an upper arm of the user serving as the measurement portion.

[0047] Operations such as those described below can be given as examples of the processes performed here. That is, after the CPU 40 has preliminarily filled the air bladder 13 by supplying a predetermined amount of air thereto, the CPU 40 inflates the air bladder 8 until the internal pressure of the air bladder 13 and the changes in the internal pressure thereof reach predetermined values ​​that have been set in advance. The measuring air bladder 13 is automatically properly wrapped around the user's upper arm, which serves as the measuring portion.

[0048] Next, in step S19, the CPU 40 performs an air inflation operation to increase the internal pressure of the measurement air bladder 13 to a predetermined internal pressure. During this operation, the CPU 40 monitors the internal pressure of the air bladder 13 obtained from the pressure sensor 23 and determines whether a predetermined pressure previously set has been reached. The "predetermined pressure" referred to here may be a pressure high enough to occlude a blood vessel. Alternatively, in the case where a measurement result of the selected user is stored in the memory 7, the predetermined pressure may be a pressure obtained by adding a predetermined value to that user's systolic blood pressure value.

[0049] When it is determined that the internal pressure of the air bladder 13 has reached the aforementioned predetermined pressure (YES in step S21), the CPU 40 performs an air discharge operation in step S23 to start the deflation of the air bladders 13 and 8. The air discharge operation continues until a blood pressure calculation (S25), which will be mentioned later, is completed.

[0050] In step S25, the CPU 40 calculates a blood pressure value based on changes in the internal pressure of the air bladder 13 during the operation to inflate the air bladder 13, which is executed in step S23. When the blood pressure value calculation is completed and a blood pressure value has been determined (YES in step S27), the CPU 40 terminates the inflating operation of step S23, quickly reduces the internal pressures of the air bladders 13 and 8 in step S29, and releases the compression to the body. Then, in step S31, the CPU 40 performs an operation to display the calculated blood pressure value on the display unit 4 as a measurement result.

[0051] This concludes the series of operations. Internal pressure control of the air bellows 13(1) Feedback control

[0052] In the aforementioned air exhaust operation of step S23, the first control unit 41 of the CPU 40 may monitor the internal pressure and changes in the internal pressure of the air bladder 13 and perform feedback control that controls the rate of change in the internal pressure so that these values ​​reach the predetermined values.

[0053] In this case, as in Fig. 4, the first control unit 41 of the CPU 40 includes a drive voltage determining unit 412 for determining a voltage for driving the pump 21, the valve 22, and so on (hereinafter referred to as a “drive voltage E1”).

[0054] The drive voltage determination unit 412 receives the internal pressure and the changes in the internal pressure of the air bladder 13 and determines the drive voltage E1 to establish a change rate in the internal pressure so that those values ​​reach the predetermined values. A control signal to drive the pump 21 and / or the valve 22 at the predetermined drive voltage E1 is generated, and the control signal is output to the drive circuit 26 and / or the drive circuit 27. (2) Forward-facing control

[0055] Alternatively, in the aforementioned ventilation operation of step S23, the first control unit 41 of the CPU 40 may execute feedforward control that controls the internal pressure and changes in the internal pressure of the air bladder 13 by outputting a control signal that has been set in advance. A case in which the feedforward control is executed will now be described in detail.

[0056] In this case, as in Fig. 4, the first control unit 31 of the CPU 40 includes a circumferential length information obtaining unit 411 for obtaining circumferential length information, which is information indicating the circumferential length of the user's measurement area, and the driving voltage determining unit 412 for determining the driving voltage E1 for driving the valve 22.

[0057] When the circumferential length information indicating that, for example, "wide", "narrow", or the like is input during measurement using, for example, a switch from which the operation unit 3 is partially configured, the circumferential length information obtaining unit 411 obtains the circumferential length information based on an operation signal from the operation unit 3. Alternatively, the circumferential length information may be obtained via an input signal from the external interface I / F 80.

[0058] Furthermore, the internal pressure control for obtaining the circumferential length information may be performed by the CPU 40, and the circumferential length information obtaining unit 411 may obtain the circumferential length information based on the result of this control. More specifically, after accepting a user's selection in the aforementioned measurement operations, the CPU 40 outputs to the drive circuit 26 a control signal for driving the pump 21 at a predetermined voltage, which is specified in advance, and inflates the air bladder 13 with air by driving the pump 21 at the predetermined voltage until the air bladder 13 reaches a predetermined pressure, which is specified in advance. The CPU 40 measures the amount of time required until the predetermined pressure is reached.The circumferential length information obtaining unit 411 stores a correspondence relationship between the amount of time required until the predetermined pressure is reached and the circumferential length, and can obtain the user's circumferential length information based on this correspondence relationship.

[0059] Here, in the case where the drive voltage for driving the pump 21 is the same, the inflation speed decreases as the circumferential length of the measurement area increases. Accordingly, the amount of time required for inflation increases as the circumferential length of the measurement area increases. In other words, the inflation time required for the air bladder 13 to reach the predetermined pressure can be taken as an index indicating the circumferential length of the measurement area. Accordingly, by previously storing correspondence relationships in which the longer the circumferential length is, the longer the amount of time required for inflation, the circumferential length information obtaining unit 411 can obtain the circumferential length based on the amount of time required for inflation.Note that this information can be obtained in the same way from the rotation frequency of the pump 21 and the pressure in the air bladder 13 instead of from the inflation time.

[0060] Alternatively, as another example, a cloth (not shown) serving as a mechanism for winding the air bladder around the measurement portion has a sliding resistance, and the circumferential length information obtaining unit 411 may obtain the circumferential length information from a resistance value obtained from the set sliding resistance when the air bladder 13 is wound around the measurement portion.

[0061] The driving voltage determination unit 412 determines the driving voltage E1 based on the circumferential length information. The determination of the driving voltage E1 by the driving voltage determination unit 412 will be described below.

[0062] Here, as in Fig. 6, a degree of change in the rate at which the pressure in an air bellows decreases differs depending on the circumferential length of the measuring area in the case where the driving voltage E1 is kept constant. Specifically, as shown in Fig. 6, the degree of change in the reduction speed increases as the circumferential length of the measuring area decreases, and the degree of change in the reduction speed decreases as the circumferential length of the measuring area increases. In other words, based on the relationship shown in Fig. 6, it can be said that the circumferential length of the measuring area serves as a parameter for determining the driving voltage E1.

[0063] Accordingly, the drive voltage determining unit 412 determines the drive voltage E1 using the aforementioned relationship shown in Fig. 6. As a specific example, the driving voltage determining unit 412 stores the following formula (1) in advance and determines the driving voltage E1 by substituting the obtained circumferential length information in the formula. Driver voltage E1=α×circumferential length−information +β

[0064] Fig. Fig. 7 is a diagram illustrating a relationship between the driving voltage E1 and the circumferential length, which is calculated using the relationship expression (1) between the circumferential length information and the driving voltage E1. Using the aforementioned formula (1), the driving voltage determining unit 412 determines a magnitude of the driving voltage E1 that is proportional to the circumferential length of the measurement area, as shown in Fig. 7 is shown.

[0065] Fig. Fig. 8 is a diagram showing rates of change in the pressure reduction rate in the air bellows 13 in the case where the circumferential length of the measuring area is the same. As in Fig. 8, in the case where the circumferential length of the measuring area is the same, the rate of change at which the pressure in the air bellows 13 decreases differs depending on the opening in the valve 22, or, in other words, depending on the magnitude of the driving voltage. Specifically, as shown in Fig. 8, the rate of change in a decreasing speed increases as the opening in the valve 22 increases, and the rate of change in a decreasing speed decreases as the opening decreases. Accordingly, based on the relationship shown in Fig. 8, it is preferable for the opening to have a size in which the decreasing speed of the air bellows 13, from the calculation of a systolic blood pressure to the calculation of a diastolic blood pressure, is within a predetermined speed range.

[0066] To be more specific, it is preferable that the gap be of a magnitude that results in a decrease rate in which the number of pressure pulse wave amplitude signals detected during ventilation between the systolic blood pressure and the diastolic blood pressure is greater than or equal to a predetermined number. It is further preferable that the aforementioned "predetermined" number be 5. The reason for this is that, as previously published in Japanese Patent No. 3,179,873 by the present applicants, considering the capabilities of an algorithm for measuring the decrease in pressure, it is acceptable to control the decrease rate so that approximately five pressure pulse wave amplitude signals are detected during ventilation between the systolic blood pressure and the diastolic blood pressure.

[0067] Note that the size of the opening in which five or more pressure pulse wave amplitude signals are measured during inflation is obtained between the systolic blood pressure and the diastolic blood pressure, for example, by experiment or the like, and is assumed to be stored in advance in the drive voltage determination unit 412. About 5 mmHg / sec to 20 mmHg / sec is preferable as a specific value thereof. Accordingly, the coefficients α and β in the aforementioned formula (1) can be set to values ​​that provide the blood pressure decrease speed in which the pressure of the air bladder 13 is within a range close to the blood pressure value to within a decrease speed of about 5 mmHg / sec to 20 mmHg / sec. It is assumed that these coefficients α and β are found in advance by experiment or the like and stored in the driving voltage determining unit 412.Although the driving voltage determining unit 412 takes the circumferential length information obtained by the listed formula (1) as an input and determines the driving voltage E1 in the above example, it should be noted that instead of the formula (1), the driving voltage determining unit 412 may store a table specifying the relationship between the circumferential length information and the driving voltage E1 and read out the driving voltage E1 corresponding to the obtained circumferential length information by referring to this table.

[0068] In the ventilation operation of the aforementioned step S23, the CPU 40 determines the driving voltage E1 corresponding to the circumferential length using the driving voltage determining unit 412, and outputs a control signal to the driving circuit 27 to hold the determined driving voltage E1 and drive the valve 22.

[0069] As a result, during inflation, the speed at which the air bellows 13 is inflated changes according to the pressure changes in the air bellows, as shown in Fig. 9A is shown.

[0070] In addition, during venting, the discharge amount from the valve 22 changes as the pressure in the air bellows 13 changes according to the pressure changes in the air bellows 13, as shown in Fig. 9B is shown.

[0071] In other words, based on the relationships that exist in Fig. 9A and Fig. 9B, controlling the drive voltage E1 to be constant, or in other words, controlling the opening in the valve 22 to be constant, can be called an equivalent to controlling the drive voltage E1 so that the discharge amount from the valve 22 and the speed at which the air bladder 13 is inflated are in a proportional relationship.

[0072] By performing such feedforward control, the CPU 40 can bring the amount of air flowing from the air bladder 13 and the speed of the venting into a proportional relationship. This makes it possible to approach a constant detection accuracy for changes in the volume of the blood vessel, which in turn makes it possible to improve the measurement accuracy. In other words, as shown in Fig. 9C, a pressure pulse wave amplitude for a constant volume change can be made constant at a value based on the circumferential length of the measuring area, regardless of changes in pressure within the air bladder 13. Internal pressure control of the air bellows 8

[0073] In the air discharge operation of the aforementioned step S23, the CPU 40 controls the internal pressure of the air bladder 8 so that the internal pressure of the air bladder 8 and the internal pressure of the air bladder 13 are in a predetermined ratio.

[0074] Fig. 10 and Fig. 11 are diagrams illustrating the relationships between a change in the internal pressure of the air bladder 8 and a change in the internal pressure of the air bladder 13; the solid lines indicate the internal pressure of the air bladder 13, whereas the dashed lines indicate the internal pressure of the air bladder 8.

[0075] As in Fig. 10, when the ratio between the internal pressure of the air bellows 8 and the internal pressure of the air bellows 13 changes during the measurement (here during the air discharge), there are cases in which the shape of the winding member 10, which is between the air bellows 8 and the air bellows 13, is unstable and deforms. For example, as shown in Fig. 10, when the internal pressure of the air bladder 8 drops below the internal pressure of the air bladder 13, the strength at which the air bladder 8 compresses the winder 10 and the air bladder 13 drops below the internal pressure of the air bladder 13. As a result, the winding member 10 is pushed outward due to the internal pressure of the air bladder 13, and vibrations resulting from this deformation may overlap with the changes in the internal pressure of the air bladder 13 and be detected. This is plotted as a "false pulse wave" and leads to a deterioration in the pulse measurement accuracy. This also causes a drop in the strength at which the air bladder 8 compresses the air bladder 13, resulting in the winding of the air bladder 13 becoming unstable over the measurement range. This also leads to a deterioration in the accuracy of the detected pulse wave.

[0076] Accordingly, as in Fig. As shown in Figure 11, during the measurement (here, during air release), the CPU 40 changes the internal pressure of the air bladder 8 so that the ratio between the internal pressure of the air bladder 8 and the internal pressure of the air bladder 13 is greater than or equal to the predetermined ratio. Such action stabilizes the winding member 10 placed between the two air bladders. (1) Feedback control

[0077] During the air discharge operation of the aforementioned step S23, the second control unit 42 of the CPU 40 may monitor the internal pressure of the air bladder 13 and the internal pressure of the air bladder 8, and may perform feedback control so that the predetermined ratio between the internal pressure of the air bladder 8 and the internal pressure of the air bladder 13 reaches a predetermined value.

[0078] In this case, as in Fig. 4, the second control unit 42 of the CPU 40 includes a drive voltage determining unit 422 for determining a voltage for driving the pump 31, the valve 32, and so on (hereinafter referred to as a “drive voltage E2”).

[0079] The drive voltage determining unit 422 obtains the internal pressure of the air bladder 13 and the internal pressure of the air bladder 8 at a predetermined timing and determines the drive voltage E2 so that the ratio between the internal pressure of the air bladder 8 and the internal pressure of the air bladder 13 becomes the predetermined ratio specified in advance. A control signal for driving the valve 32 at the predetermined drive voltage E2 is generated, and the control signal is output to the drive circuit 37. Note that the aforementioned predetermined ratio is a value determined in advance through experimentation or the like, and is assumed to be stored in the second control unit 42 in advance.

[0080] At this time, even if the aforementioned feedback control is performed by the first control unit 41, the feedforward control can also be performed on the internal pressure of the air bellows 13.

[0081] Through this control, during air release, the internal pressure of the air bellows 8 can be changed so that the ratio between the internal pressure of the air bellows 8 and the internal pressure of the air bellows 13 becomes a predetermined ratio. As a result, the winding member 10, which is placed between the air bellows 13 and the air bellows 8, can be prevented from deforming during measurement (during air release), which in turn makes it possible to improve the measurement accuracy. (2) Forward-facing control

[0082] Alternatively, in the case where the first control unit 41 performs the stated forward control in the aforementioned step S23, the second control unit 42 of the CPU 40 may perform a forward control that controls the internal pressure of the air bladder 8 by outputting a control signal based on a preset control signal output by the first control unit 41.

[0083] In this case, as in Fig. 4, the second control unit 42 of the CPU 40 includes the drive voltage determining unit 442 for determining the drive voltage E2 for driving the pump 31, the valve 32, and so on.

[0084] The drive voltage determining unit 422 obtains the drive voltage E1 determined as described above by receiving the control signal output from the first control unit 41. Then, the drive voltage E2 is calculated so that the internal pressure of the air bladder 8 becomes a value that reaches the predetermined ratio relative to the internal pressure of the air bladder 13 subject to steady-state control; the determined drive voltage E2 is then output to the drive circuits 36 and 37. Note that the aforementioned predetermined ratio is a value determined in advance through experimentation or the like, and is assumed to be stored in the second control unit 42 in advance.

[0085] By this, when the internal pressure of the air bladder 13 is changed during air discharge as a result of feedforward control so that the air flow rate from the air bladder 13 and the air discharge speed approach a proportional relationship, the internal pressure of the air bladder 8 can be changed so that the ratio between the internal pressure of the air bladder 8 and the internal pressure of the air bladder 13 becomes the predetermined ratio. As a result, the winding member 10 interposed between the air bladder 13 and the air bladder 8 can be prevented from being deformed during measurement (during air discharge), which in turn makes it possible to improve the measurement accuracy. (3) Ratio of the internal pressures of the air bellows 13 and the air bellows 8 during forward control

[0086] In the above examples, it is assumed that the ratio of the internal pressures of the air bladder 13 and the air bladder 8 during air discharge is a predetermined ratio determined in advance by experimentation or the like, and that the ratio is stored in advance in the second control unit 42.

[0087] However, the drive voltage determination unit 422 may perform calculations based on the predetermined input values, store predetermined specific ratios between input values ​​and the predetermined ratio, and specify the predetermined ratio based on an input value. The circumferential length of the measurement area, the user's blood pressure value, the cuff size, and the maximum inflation value of the air bladder 13 can be given as examples of the input values. Examples of each of these input values ​​are described below. If the ratio is used based on the circumference of the measuring area

[0088] In this case, as in Fig. 4, the second control unit 42 includes an obtaining unit 421 for obtaining the circumferential length information, which is information indicating the circumferential length of the user's measurement range. The obtaining unit 421 obtains the circumferential length of the measurement range in the same manner as the circumferential length information obtaining unit 411. In other words, when the circumferential length information indicating, for example, "wide," "narrow," or the like is input during measurement by using, for example, a switch from which the operation unit 3 is partially configured, the obtaining unit 421 obtains the circumferential length information based on an operation signal from the operation unit 3. Alternatively, the circumferential length information may be obtained via input from the external interface I / F 80.

[0089] Furthermore, the internal print control for obtaining the circumferential length information may be executed by the CPU 40, and the obtaining unit 421 may obtain the circumferential length information based on the result of this control. The internal print control for obtaining the circumferential length information may be the same as the control for obtaining the circumferential length information using the circumferential length information obtaining unit 411.

[0090] The driving voltage determining unit 422 stores in advance a correspondence relationship or expression between the circumferential length and the ratio of the internal pressure of the air bellows 8 to the internal pressure of the air bellows 13. Fig. 12 is a diagram showing a specific example of a relationship between an upper arm circumference, which serves as a specific example of the circumferential length, and the predetermined ratio indicating the ratio of the internal pressures of the air bladder 13 and the air bladder 8. Specifically, as shown in Fig. 12, the driving voltage determining unit 422 determines a correspondence relationship or expression in which the ratio of the internal pressure of the air bladder 8 to the internal pressure of the air bladder 13 increases as the circumferential length of the measurement area increases.

[0091] The driving voltage determination unit 422 refers to the stored matching relationship, specifies the ratio corresponding to the circumferential length of the user's measurement area obtained by the obtaining unit 421, and determines the driving voltage E2 so that the ratio of the internal pressure of the air bladder 8 to the internal pressure of the air bladder 13 becomes the steady-state ratio. Alternatively, the driving voltage E2 is calculated by substituting the obtained circumferential length of the user's measurement area into the listed relationship expression. A control signal is then generated and output.

[0092] Thereby, the control is carried out so that the ratio of the internal pressure of the air bellows 8 to the internal pressure of the air bellows 13 becomes a ratio based on the circumferential length of the user's measuring range. When the ratio based on the user’s blood pressure value is used

[0093] In this case, as in Fig. 4, the second control unit 42 uses the obtaining unit 421 to obtain a blood pressure value of the user.

[0094] In the case where the measurement operations that calculate the blood pressure value during the deflation process are performed as in this example, the obtaining unit 421 can obtain an estimated value for the blood pressure value during the inflation process in the air bladder 13 as the user's blood pressure value. In other words, in this case, the calculating unit 43 calculates the user's blood pressure value based on changes in the internal pressure of the air bladder 13 during the inflation process and inputs this value to the second control unit 42 as the estimated value.

[0095] Alternatively, in the case where a blood pressure value is stored in the memory 7 as a measurement result for that user, the obtaining unit 421 may obtain the user's blood pressure value by reading that blood pressure value from a predetermined range in the memory 7. Note that in this case, the most recent blood pressure value may be read out, or the average value of the blood pressure values ​​in a predetermined range may be used.

[0096] Note also that the blood pressure value referred to here can be a systolic blood pressure value, a diastolic blood pressure value, or an average blood pressure value, which is an average of these. The systolic blood pressure value is assumed to be used in the following example.

[0097] The driving voltage determining unit 422 stores in advance a correspondence relationship or a comparison expression in which the ratio of the internal pressure of the air bladder 8 to the internal pressure of the air bladder 13 decreases as the user's systolic blood pressure value increases.

[0098] The driving voltage determination unit 422 refers to the stored matching relationship, specifies the ratio corresponding to the user's blood pressure value obtained by the obtaining unit 422, and determines the driving voltage E2 so that the ratio of the internal pressure of the air bladder 8 to the internal pressure of the air bladder 13 becomes the steady-state ratio. Alternatively, the driving voltage E2 is calculated by substituting the obtained user's blood pressure value in the comparison expression shown. A control signal is then generated and output.

[0099] By this, the control is carried out so that the ratio of the internal pressure of the air bellows 8 to the internal pressure of the air bellows 13 becomes a ratio which is based on the blood pressure value of the user. When using the ratio based on cuff size

[0100] In the case where the cuff size is variable, the second control unit 42, as in Fig. 4, include the obtaining unit 421 to obtain the dimension information, which is information indicating the cuff size, to create a ratio based on the cuff size.

[0101] Here, the cuff size corresponds to the volume size of the air bladders 13 and 8; the volumes of the air bladders 13 and 8 are large when the cuff size is large, whereas the volumes of the air bladders 13 and 8 are small when the cuff size is small. A case where the cuff size is variable corresponds to a case where, for example, the body compression / stabilization unit is contained in the inner peripheral portion of the housing 60, or the housing itself can be removed and replaced from the main body 2, and a body compression / stabilization unit, the housing 60 containing this unit, and so on, based on the cuff size, are connected to the main body 2 and used.

[0102] For example, when a cuff size such as "large," "medium," or "small" is input during measurement using a switch or the like from which the operation unit 3 is partially configured, the obtaining unit 421 obtains the cuff size from an operation signal from the operation unit 3. Alternatively, the cuff size may be obtained via input from the external interface I / F 80. Furthermore, in the case where a sensor or the like that detects the type of the body compression / stabilization unit or the housing 60 is provided at a connection portion between the body compression / stabilization unit or the housing 60 and the main body 2, the obtaining unit 421 may determine the cuff size based on a signal output from the sensor.

[0103] The driving voltage determining unit 422 stores in advance a correspondence relationship or a comparison expression between the cuff size and the ratio of the internal pressure of the air bladder 8 to the internal pressure of the air bladder 13. Specifically, the driving voltage determining unit 422 stores a correspondence relationship or a comparison expression in which the ratio of the internal pressure of the air bladder 8 to the internal pressure of the air bladder 13 increases as the cuff size increases.

[0104] The driving voltage determination unit 422 refers to the stored matching ratio, specifies the ratio corresponding to the cuff size obtained by the obtaining unit 421, and determines the driving voltage E2 so that the ratio of the internal pressure of the air bladder 8 to the internal pressure of the air bladder 13 becomes the specified ratio. Alternatively, the driving voltage E2 is calculated by substituting the obtained cuff size in the specified comparison expression. A control signal is then generated and output.

[0105] By this, the control is carried out so that the ratio of the internal pressure of the air bellows 8 to the internal pressure of the air bellows 13 becomes a ratio based on the cuff size. If the ratio based on the maximum inflation value of the air bellows 13 is used

[0106] In this case, as in Fig. 4, the second control unit 42 includes the obtaining unit 421 for obtaining a maximum inflation value of the air bladder 13. The "maximum inflation value of the air bladder 13" referred to herein indicates a maximum value for the internal pressure of the air bladder 13 during the inflation process, and the obtaining unit 421 obtains the maximum inflation value of the air bladder 13 by monitoring the internal pressure of the air bladder 13 detected by the pressure sensor 23 during the inflation process.

[0107] Alternatively, the obtaining unit 421 may obtain the maximum inflation value from the user's blood pressure value. In this case, as mentioned above, the obtaining unit 421 obtains the user's blood pressure value.

[0108] The driving voltage determining unit 422 stores in advance a correspondence relationship or a comparison expression between the maximum inflation value of the air bladder 13 and the ratio of the internal pressure of the air bladder 8 to the internal pressure of the air bladder 13. Specifically, the driving voltage determining unit 422 stores a correspondence relationship or a comparison expression in which the ratio of the internal pressure of the air bladder 8 to the internal pressure of the air bladder 13 decreases as the maximum inflation value of the air bladder 13 increases.

[0109] The driving voltage determination unit 422 refers to the stored matching ratio, specifies the ratio corresponding to the maximum inflation value of the air bladder 13 obtained by the obtaining unit 421, and determines the driving voltage E2 so that the ratio of the internal pressure of the air bladder 8 to the internal pressure of the air bladder 13 becomes the specified ratio. Alternatively, the driving voltage E2 is calculated by substituting the obtained maximum inflation value in the specified comparison expression. A control signal is then generated and output.

[0110] By this, the control is carried out so that the ratio of the internal pressure of the air bellows 8 to the internal pressure of the air bellows 13 becomes a ratio based on the maximum inflation value of the air bellows 13. If a combination of the above is used

[0111] The above examples are examples in which the drive voltage determination unit 422 specifies the ratio of the internal pressure of the air bladder 8 to the internal pressure of the air bladder 13, using one of the circumferential length of the measurement area, the user's blood pressure value, the cuff size, and the maximum inflation value of the air bladder 13 as the input value. However, the invention is not limited to only one of the aforementioned examples, and the predetermined ratio may be specified using a combination of two or more of these examples.

[0112] For example, the driving voltage determination unit 422 may specify a ratio based on the user's circumference length and blood pressure value as input values. In this case, the obtaining unit 421 obtains the user's circumference length and blood pressure value.

[0113] The driving voltage determining unit 422 stores in advance a matching relationship or a comparison expression between the circumferential length and the blood pressure value of the user and the ratio of the internal pressure of the air bladder 8 to the internal pressure of the air bladder 13. Fig. 14 is a diagram illustrating a specific example of a relationship between an upper arm circumference, which serves as a specific example of the circumferential length, the systolic blood pressure value, which serves as a specific example of the blood pressure value, and the predetermined ratio indicating the ratio of the internal pressure of the air bladder 13 and the air bladder 8. A relational expression such as: Ratio = α × upper arm circumference + β × SBP (where α and β are coefficients and SBP is the systolic blood pressure value) can be given as the relational expression. In this specific case, as in Fig. 14, the driving voltage determining unit 422 stores a matching ratio or comparison expression in which the ratio of the internal pressure of the air bladder 8 to the internal pressure of the air bladder 13 increases as the circumferential length of the measurement area increases, and the ratio of the internal pressure of the air bladder 8 to the internal pressure of the air bladder 13 decreases as the systolic blood pressure value increases.

[0114] The driving voltage determination unit 422 refers to the stored matching ratio, specifies the ratio corresponding to the user's circumferential length and blood pressure value obtained by the obtaining unit 421, and determines the driving voltage E2 so that the ratio of the internal pressure of the air bladder 8 to the internal pressure of the air bladder 13 becomes the specified ratio. Alternatively, the driving voltage E2 is obtained by substituting the obtained circumferential length and the user's blood pressure value in the specified comparison expression. A control signal is then generated and output.

[0115] By this, the control is carried out so that the ratio of the internal pressure of the air bellows 8 to the internal pressure of the air bellows 13 becomes a ratio based on the circumferential length and the blood pressure value of the user.

[0116] By the second control unit 42 determining the ratio of the internal pressures of the air bladder 13 and the air bladder 8 in this way during forward control, the ratio of the internal pressure of the air bladder 8 to the internal pressure of the air bladder 13 can be adjusted to the optimal ratio for the user, the circumstances at the time of measurement, etc. This makes it possible to maintain the strength at which the air bladder 8 compresses the air bladder 13 at the optimal level during measurement (during air discharge), which in turn makes it possible to improve measurement accuracy. (4) Control of the ratio of the internal pressures of the air bellows 13 and the air bellows 8 during forward control

[0117] In the above example, the second control unit 42 determines the ratio of the internal pressures of the air bladder 13 and the air bladder 8 at a predetermined timing during air discharge, such as at the start of air discharge, and outputs a control signal so that the ratio determined at this timing is maintained thereafter.

[0118] However, the second control unit 42 may change the determined ratio at a predetermined timing. A measured internal pressure of the air bladder 13 (or a pulse wave amplitude obtained from an internal pressure), a compression strength of the air bladder 8, and an amount of time elapsed from the start of deflation can be given as examples of the predetermined timing.

[0119] In this case, as in Fig. 4, the second control unit 42 includes the obtaining unit 421 for obtaining the measured internal pressure of the air bladder 13 (or a pulse wave amplitude obtained from an internal pressure), the strength of compression by the air bladder 8, or the amount of elapsed time from the start of deflation.

[0120] The drive voltage determination unit 422 stores in advance the listed predetermined ratio for each measured internal pressure of the air bladder 13 (or the pulse wave amplitude obtained from an internal pressure), the strength of compression by the air bladder 8, or the elapsed time from the start of deflation. It is then determined at predetermined intervals whether the measured internal pressure of the air bladder 13 (or the pulse wave amplitude obtained from an internal pressure), the strength of compression by the air bladder 8, or the elapsed time from the start of deflation has reached the stored timing to perform the change.In the case where it has been determined that the timing to perform the change has been reached, the driving voltage determining unit 422 reads the ratio based on this timing, determines the driving voltage E2 so that the ratio of the internal pressure of the air bladder 8 to the internal pressure of the air bladder 13 is this ratio, and generates and outputs a control signal.

[0121] Alternatively, the second control unit 42 may change the specified predetermined ratio by using a timing such as the predetermined timing at which the rate of change in the internal pressure of the air bladder 13 has reached a predetermined rate of change in a pressure segment when the internal pressure of the air bladder 13 is between the predetermined pressures P1 and P2. For example, a pressure segment between the maximum inflation value of the air bladder 13 and the value (maximum inflation value - 50 mmHg) can be given as an example of the specified pressure segment.

[0122] In addition, the predetermined ratio may be changed based on a timing determined based on a combination of two or more of the conditions of the measured internal pressure of the air bladder 13, the strength of compression by the air bladder 8, and an amount of time elapsed from the start of air discharge, in the same manner as when the ratio between the internal pressure of the air bladder 13 and the internal pressure of the air bladder 8 is determined.For example, the driving voltage determining unit 422 may store in advance a relationship between the predetermined ratio and the internal pressure of the air bladder 13 and the amount of compression by the air bladder 8, and may change the listed predetermined ratio to the ratio specified according to the combination of the predetermined ratio and the internal pressure of the air bladder 13 and the amount of compression by the air bladder 8 at the lapse of time at which those conditions were met. .

[0123] By this, the relationship between the internal pressures of the air bellows 13 and the air bellows 8 can be properly maintained as the measurement proceeds, which makes it possible to improve the measurement accuracy. Second embodiment

[0124] In the blood pressure monitor 1 according to the first embodiment, the air bellows 8 is used as a member to compress the air bellows 13 on the measuring area above the winding member 10.

[0125] However, the configuration for compressing the air bellows 13 on the measuring area is not limited to an air bellows over the winding member 10, and another compression mechanism may be applied. As another such example, Fig. 15 shows an overview of a blood pressure monitor 1' according to a second embodiment.

[0126] As in Fig. As shown in Fig. 15, the sphygmomanometer 1' according to the second embodiment includes a wire 81 for pressing the air bladder 13 against the measuring portion instead of the air bladder 8 and the winding member 10 of the sphygmomanometer 1, and a wire receiving unit 82 serving as a mechanism for receiving the wire 81 instead of the pump 31 and the valve 32. One end of the air bladder 13 is anchored to the cuff, and the other end is connected to the listed wire. Alternatively, the configuration may be such that the listed wire is connected to both ends of the air bladder 13.

[0127] A driver circuit (not shown) corresponding to the driver circuits 36 and 37 is connected to the CPU 40 and drives the wire take-up unit 82 according to a control signal from the CPU 40. Fig. 16 is a graph illustrating a correspondence between changes in a voltage applied to the drive circuit of the wire take-up unit 82 to drive the wire take-up unit 82 (a drive voltage E3) and changes in the internal pressure of the air bladder 13 compressed to the measurement area by the wire 81; the upper portion of the graph shows the changes in the drive voltage E3, whereas the lower portion of the graph shows the changes in the internal pressure of the air bladder 13. As in Fig. Here, as shown in Figure 16, the changes in the drive voltage E3 and the changes in the internal pressure of the air bladder 13 generally correspond to each other. Thus, the degree to which the wire 81 compresses the air bladder 13 is controlled by controlling the drive voltage E3.

[0128] The other configurations of the blood pressure monitor 1' are generally the same as the configurations of the blood pressure monitor 1. In other words, the CPU 40 includes the first control unit 41, and the feedback control or the feedforward control is performed by the first control unit 41 on the internal pressure of the air bladder 13 during air discharge.

[0129] The CPU 40 also includes the second control unit 42, and the second control unit 42 can perform the feedback control on the internal pressure of the air bladder 8 during the air discharge, or the feedforward control can be performed in the case where the feedforward control is performed on the internal pressure of the air bladder 13.

[0130] The specific details of these controls are generally the same as those in the blood pressure monitor 1. However, in the blood pressure monitor 1', the second control unit 42 controls the wire take-up unit 82 instead of controlling the pump 31 and the valve 32. Accordingly, the drive voltage determining unit 422 of the second control unit 42 determines the drive voltage E3 in the same manner as the aforementioned drive voltage E2 and outputs a control signal.

[0131] In this way, even if the member for compressing the air bladder 13 on the measuring area has a configuration lateral to the air bladder 8 and the winding member 10, the second control unit 42 outputs a control signal to the mechanism that adjusts the compression strength in the same manner as the method described in the first embodiment; this makes it possible to prevent the deformation in the winding member 10 placed between the air bladder 13 and the compression member during measurement (during air discharge), which in turn makes it possible to improve the measurement accuracy.

[0132] Note that the above example describes the CPU 40 calculating the blood pressure value based on changes in the internal pressure of the air bladder 13 when the air bladder 13 is deflating. However, as another example, the CPU 40 may calculate the blood pressure value based on changes in the internal pressure of the air bladder 13 when the air bladder 13 is being filled with air. In this case, replacing "during air deflating" with "during air inflating" in the aforementioned descriptions of the internal pressure enables the controller to control the internal pressure during measurement in the same way. Accordingly, in the same manner as described above, the winding member 10 placed between the air bladder 13 and the compression member can be prevented from deforming during measurement (during air inflating), which conversely makes it possible to improve the measurement accuracy.

[0133] Note that the embodiment disclosed above is to be understood as being exemplary in every way and not limiting in any way. The scope of the present invention is defined not by the aforementioned descriptions, but by the scope of the appended claims, and all changes that fall within the same essential spirit as the scope of the claims are intended to be embraced therein as well. List of reference symbols 1.1' blood pressure monitor 2 Main part 3 Control unit 4 Display unit 5 measuring section 6, 7 memory 13, 8 air bellows 10 winding links 20, 30 air system 21, 31 pump 22, 32 valve 23, 33 Pressure sensor 26, 27, 36, 37 driver circuit 28, 38 Oscillation circuit 29, 39 converters 41 first control unit 42 second control unit 43 Calculation unit 44 Display control unit 60 housings 70 Cover 80 external interface I / F 81 wire 82 Wire take-up unit 100 upper arm 411 Circumference length information preservation unit 412, 422 Driver voltage determination circuit 421 conservation unit E1, E2, E3 driver voltage

Claims

[1] Electronic blood pressure monitor (1), which comprises: a first fluid bellows (13); a first adjusting unit (20) for injecting / ejecting a fluid into / from the first fluid bladder (13) at a variable speed; a sensor (23) for detecting an internal pressure of the first fluid bellows (13); a winding unit (10) for winding the first fluid bladder (13) around a measuring area of ​​a measuring person at a variable winding thickness; a second adjusting unit (30) for adjusting the winding thickness of the winding unit (10); and a control unit (40-42), wherein the control unit (40-42) executes: a first control process which outputs a first control signal to the first setting unit (20) so that a rate of change in the internal pressure and / or the fluid amount in the fluid bladder becomes a predetermined rate of change; a second control process which outputs a second control signal to the second setting unit (30) so that the winding thickness reaches a predetermined relationship with the rate of change in the internal pressure and / or fluid amount in the first fluid bladder (13) under the first control process; and a calculation process which calculates a blood pressure value of the measured person based on a change in the internal pressure of the first fluid bladder (13) detected under the first control process, wherein the control unit (40-42) sets the predetermined ratio to a previously set ratio or changes the predetermined ratio by using a previously set compensation formula corresponding to at least one of a circumferential length of the measurement area, an already measured blood pressure value of the measurement subject, a blood pressure value of the measurement subject estimated during inflation, a size of the first fluid bladder (13), and a maximum value of the pressure in the first fluid bladder (13). [2] Electronic blood pressure monitor (1) according to claim 1, wherein the first control signal is set in advance so that the rate of change in the internal pressure in the first fluid bladder (13) and the rate of change in the fluid amount in the first fluid bladder (13) are in a proportional relationship; wherein the second control signal is adjusted in advance according to the first control signal to achieve the predetermined ratio; and wherein the control unit (40-42) performs feedforward control on the first control process and the second control process. [3] Electronic blood pressure monitor (1) according to claim 1, wherein the winding unit (10) includes a second fluid bellows (8) which is placed farther from the measuring area than the first fluid bellows (13) when worn on the measuring area; wherein the second adjustment unit (30) includes a pump (31) for injecting and / or a valve (32) for ejecting the fluid into / from the second fluid bladder (8) at a variable speed; and wherein the second control process includes a process for determining a drive voltage for the pump (31) and / or the valve (32). [4] Electronic blood pressure monitor (1) according to claim 1, wherein the control unit (40-42) determines the circumferential length of the measuring area and / or the dimension of the first fluid bladder (13) based on a rate of change in the internal pressure of the first fluid bladder (13) during inflation. [5] Electronic blood pressure monitor (1) according to claim 1, wherein the control unit (40-42) determines the blood pressure value of the measured person by obtaining a previous measurement result. [6] Electronic blood pressure monitor (1) according to claim 1, wherein in the calculation process, the control unit (40-42) calculates the blood pressure value based on a change in the internal pressure in the first fluid bladder (13) when air is discharged from the first fluid bladder (13) under the first control process; and wherein the control unit (40-42) takes the blood pressure value calculated based on a change in the internal pressure in the first fluid bladder (13) when the first fluid bladder (13) is inflated with air when a blood pressure value of the measured person is used to determine the predetermined ratio. [7] Electronic blood pressure monitor (1) according to claim 1, further comprising: an input unit for accepting an input signal of at least one of a circumferential length of the measuring area, the already measured blood pressure value of the person being measured, a dimension of the first fluid bellows (13) and a maximum value of the pressure in the first fluid bellows (13). [8] Electronic blood pressure monitor (1) according to claim 1, further comprising: a readout unit for reading out from another device at least one of a circumferential length of the measuring area, the already measured blood pressure value of the person being measured, a dimension of the first fluid bellows (13) and a maximum value of the pressure in the first fluid bellows (13). [9] The electronic blood pressure monitor (1) according to claim 1, wherein the control unit (40-42) changes the predetermined ratio to a preset ratio or changes the predetermined ratio by using a preset compensation formula at at least one of a time when the internal pressure of the first fluid bladder (13) reaches a preset level, a time when the winding strength reaches a preset level, and a time when a preset amount of time has elapsed following a preset timing of a measurement process. [10] The electronic blood pressure monitor (1) according to claim 1, wherein the control unit (40-42) changes the predetermined ratio to a preset ratio or changes the predetermined ratio by changing a preset compensation formula according to a dimension of a pulse wave amplitude detected from the internal pressure of the first fluid bladder (13). [11] A control method for an electronic blood pressure monitor (1), the electronic blood pressure monitor (1) including: a first fluid bladder (13), a first setting unit (20) for injecting / ejecting a fluid into / from the first fluid bladder (13) at a variable speed, a sensor (23) for detecting an internal pressure of the first fluid bladder (13), and a winding unit for winding the first fluid bladder (13) around a measurement area of ​​a measurement subject at a variable winding thickness, and the control method comprising: a step of controlling the first adjusting unit (20) so that a rate of change in the internal pressure and / or a fluid amount in the first fluid bladder (13) becomes a predetermined rate of change; a step of controlling a second adjusting unit (30) so that the winding strength reaches a predetermined ratio with the rate of change in the internal pressure and / or fluid amount in the first fluid bladder (13) under the control in the step of controlling the first adjusting unit (20), wherein the predetermined ratio is set to a predetermined ratio or the predetermined ratio is changed by using a predetermined compensation formula corresponding to at least one of a circumferential length of the measurement area, an already measured blood pressure value of the measurement subject, a blood pressure value of the measurement subject estimated during inflation, a size of the first fluid bladder (13), and a maximum value of the pressure in the first fluid bladder (13); and a step of calculating a blood pressure value of the measurement subject based on a change in the internal pressure of the first fluid bladder (13) detected under the control in the step of controlling the first setting unit (20).

Images