JP2012115413A - Electronic sphygmomanometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic sphygmomanometer capable of suppressing the influence given to a measurement caused by fluctuation of air volume injected into an airbag for the measurement caused by the surrounding environment, and improving the accuracy of the measurement.SOLUTION: In the electronic sphygmomanometer, when the airbag for the measurement is wound round a measuring site, whether the wound-round condition is appropriate or not is decided based on the change of the inner pressure of the airbag by pressing from the outside after a specified amount of air is injected into the airbag immediately after starting a winding operation. In the electronic sphygmomanometer, the atmospheric temperature T around a pump for injecting the air into the airbag when the winding operation is started is acquired (S101), and with reference to a corresponding relation between the atmospheric temperature and the driving quantity memorized in advance, the driving quantity in accordance with the atmospheric temperature T is determined (S103). Then, by driving the pump by the driving quantity (S107), it is possible to make the air quantity to be injected into the airbag when starting the winding operation to be a definite quantity without receiving an influence of the atmospheric temperature.

Description

  The present invention relates to an electronic sphygmomanometer, and more particularly, to an electronic sphygmomanometer in which an arm band (cuff) containing a fluid bag is wrapped around a measurement site.

  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.

  Conventionally, diagnosis has been performed based on blood pressure measured at a medical institution such as during a hospital visit or during a medical examination (anytime blood pressure). However, recent studies have shown that blood pressure measured at home (home blood pressure) is more useful for diagnosis of cardiovascular diseases than blood pressure at any time. Accordingly, blood pressure monitors used at home have become widespread.

  Many home sphygmomanometers employ blood pressure measurement methods based on oscillometric methods or microphone methods. In oscillometric blood pressure measurement, an arm band (cuff) containing a fluid bag is wrapped around a measurement site such as the upper arm, and the internal pressure (cuff pressure) of the cuff is increased by a predetermined pressure (for example, 30 mmHg) higher than the systolic blood pressure. Then, the arterial volume change in the process of gradually or gradually reducing the cuff pressure is detected as a pressure change (pressure pulse wave amplitude) superimposed on the cuff pressure, and the systolic phase is determined from the change in the pressure pulse wave amplitude. A method for determining blood pressure and diastolic blood pressure. In the oscillometric method, it is also possible to measure the blood pressure by detecting the pressure pulse wave amplitude generated during the pressurization of the cuff pressure.

  On the other hand, the microphone method wraps a cuff around a measurement site such as the upper arm and presses the cuff pressure higher than the systolic blood pressure by a predetermined pressure, as in the oscillometric method. After that, the Korotkoff sound generated from the artery in the process of gradually reducing the cuff pressure is detected by a microphone provided in the cuff, and the cuff pressure at which the Korotkoff sound is generated is detected as the systolic blood pressure, the cuff with the Korotkoff sound attenuated or disappeared. This is a method for determining the pressure as a diastolic blood pressure.

  In any method, the sphygmomanometer has a problem that if the cuff is not properly wound around the measurement site, the cuff pressure is not sufficiently transmitted to the artery and the measurement accuracy is lowered. For example, the blood pressure value measured in a state where the cuff is loosely wound around the measurement site may be measured higher than the true blood pressure value.

  Most home sphygmomanometers have a structure in which a measurer himself wraps a cuff around a measurement site. For this reason, there is a case where the cuff winding varies depending on each measurer or every time the same measurer performs measurement. As a result, the measured blood pressure value may also vary.

  Therefore, the applicant of the present application discloses an electronic sphygmomanometer having a function of determining whether or not the cuff winding degree is appropriate in Japanese Patent Application Laid-Open No. 2005-305028 (Patent Document 1). Specifically, a mechanism for winding the fluid bag around the measurement site (for example, a wrapping fluid bag) after passing the measurement site through the measurement fluid bag and injecting a predetermined amount of fluid at the start of measurement. ) Is gradually increased, and the change in the internal pressure of the fluid bag for measurement at that time is monitored. Then, when the amount of change exceeds a threshold value, it is determined that the fluid bag is appropriately wound around the measurement site.

JP 2005-305028 A

  However, if the amount of fluid injected into the measurement fluid bag at the start of measurement in the technique of Document 1 varies, it will not be possible to accurately determine how the fluid bag is wrapped around the measurement site. As a result, the cuff winding also varies.

  Furthermore, this fluid amount variation also affects the blood pressure measurement accuracy by the oscillometric method. That is, the change in volume of the measurement fluid bag due to the change in arterial volume is detected as a change in pressure (hereinafter referred to as a pressure pulse wave). Therefore, if there is a variation in the amount of fluid in the measurement fluid bag, even if the same arterial volume change occurs, the detected pressure pulse wave varies. For example, when the amount of fluid is large, the detected pressure pulse wave is small. Conversely, when the amount of fluid is small, the detected pressure pulse wave is large.

  Similarly, when the cuff winding varies due to the fluid amount variation, it also affects the blood pressure measurement accuracy by the Korotkoff sound method. That is, when the cuff wrapping becomes looser than appropriate, the compression force of the artery is reduced, and as a result, the blood pressure is measured high.

  The present invention has been made in view of such problems, and in particular, has a function of determining whether or not the degree of wrapping of an arm band (cuff) including a fluid bag around a measurement site is appropriate. Another object of the present invention is to provide an electronic sphygmomanometer capable of suppressing variations in the amount of fluid injected into a fluid bag and, as a result, improving measurement accuracy.

  In order to achieve the above object, according to one aspect of the present invention, an electronic sphygmomanometer includes a fluid bag for wrapping around a measurement site of a subject, a sensor for detecting the internal pressure of the fluid bag, and a fluid in the fluid bag. Adjustment means for injecting / extracting blood, an acquisition means for acquiring information on the surrounding environment of the sphygmomanometer, and a control means. The control means controls the adjusting means so as to inject a predetermined amount of fluid into the fluid bag immediately after the measurement operation starts, and winds the measurement site based on the amount of change in internal pressure when the fluid bag is wrapped around the measurement site. Calculating means for calculating a blood pressure value of a subject based on a change in the internal pressure of the fluid bag under control of increasing or decreasing the internal pressure of the fluid bag after detecting the strength and winding the fluid bag around the measurement site; Correction means for correcting an influence caused by a change in the amount of fluid injected into the fluid bag when the fluid bag is wound around the measurement site according to the acquired surrounding environment.

  Preferably, the correction means determines the amount of fluid to be injected into the fluid bag immediately after the measurement operation is started, based on information on the surrounding environment.

  Preferably, the correction unit determines a threshold value used in processing for detecting a degree of winding around the measurement site based on information on the surrounding environment.

  Preferably, the correction unit determines a parameter used in the process of calculating the blood pressure value of the subject based on information on the surrounding environment.

  Preferably, the correction unit determines a correction amount of the blood pressure value calculated by the calculation unit based on information on the surrounding environment, and corrects the blood pressure value.

Preferably, the acquisition means includes a sensor for measuring the surrounding environment.
Preferably, the acquisition means includes means for communicating with another device, and acquires the surrounding environment from the other device.

  Preferably, the ambient environment is the ambient temperature around the adjusting means.

  According to the present invention, it is possible to improve the measurement accuracy by suppressing the influence on the measurement because the amount of fluid injected into the measurement fluid bag of the electronic blood pressure monitor varies depending on the surrounding environment.

  Hereinafter, in this embodiment, the fluid is air and the fluid bag is an air bag.

It is a perspective view which shows the specific example of the external appearance of the blood-pressure measuring apparatus (henceforth a blood pressure meter) concerning 1st Embodiment. It is a cross-sectional schematic diagram of a sphygmomanometer during blood pressure measurement. It is a block diagram which shows the specific example of a structure of the blood pressure meter concerning 1st Embodiment. The effect of ambient temperature on the relationship between the voltage applied to the pump for injecting air into the measurement air bag and the flow rate of air injected into the air bag by the pump (injection amount per unit time) FIG. It is a figure which shows the influence of the atmospheric pressure as an ambient environment with respect to the relationship between the applied voltage to the pump for injecting air into a measurement air bag, and the flow volume of the air inject | poured into an air bag by this pump. It is a figure which shows the specific example of the table which prescribes | regulates correspondence with the voltage applied to the pump for inject | pouring air into a measurement air bag. It is a flowchart which shows the blood-pressure measurement operation | movement of the sphygmomanometer concerning 1st Embodiment. It is a flowchart which shows the winding operation | movement with the blood pressure meter concerning 1st Embodiment. It is a figure for demonstrating the example of determination of a winding state. It is a block diagram which shows the specific example of a structure of the blood pressure meter concerning 2nd Embodiment. It is a flowchart which shows the winding operation | movement with the blood pressure meter concerning 2nd Embodiment. It is a figure showing the relationship between the drive time of the pump for inject | pouring air into the measurement air bag measured about different test subjects A, B, and C, and the maximum value of the measured pulse wave amplitude. It is a figure showing the relationship between the internal pressure of an air bag and the measured pulse wave amplitude. It is a block diagram which shows the specific example of a structure of the blood pressure meter concerning 3rd Embodiment. It is a flowchart which shows the operation | movement for the blood-pressure calculation in the blood pressure meter concerning 3rd Embodiment. It is a block diagram which shows the specific example of a structure of the blood pressure meter concerning 4th Embodiment. It is a flowchart which shows the operation | movement for blood-pressure calculation in the blood pressure meter concerning 4th Embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description, the same parts and components are denoted by the same reference numerals. Their names and functions are also the same.

[First Embodiment]
<Device configuration>
FIG. 1 is a perspective view showing a specific example of the external appearance of a blood pressure measurement device (hereinafter referred to as a sphygmomanometer) 1A according to the first embodiment. FIG. 1 shows a sphygmomanometer of a type in which a measurement air bag is automatically wound around an upper arm, which is a measurement site of a user, as a specific example of a blood pressure measurement device. However, the blood pressure measurement device according to the present invention is not limited to the type in which the air bag is automatically wound around the measurement site as described above, and may be of the type in which the measurer winds. In addition, the example of FIG. 1 is a type that realizes automatic winding by the air pressure by the air bag for winding, but the type that realizes winding by other power such as a motor instead of the air pressure. It may be a thing.

  Referring to FIG. 1, a sphygmomanometer 1 </ b> A mainly includes a main body 2 placed on a desk or the like, and a measurement unit 5 for inserting an upper arm that is a measurement site. An upper part of the main body 2 includes an operation unit 3 on which a power switch, a measurement switch, a stop switch, a user selection switch, and the like are arranged, a display unit 4, and an elbow rest. The measurement unit 5 is attached to the main body 2 at a variable angle, and includes a housing 60 that is a substantially cylindrical machine frame, and a living body compression fixing device that is housed in the inner periphery of the housing 60. As shown in FIG. 1, the living body pressing and fixing device housed in the inner peripheral portion of the housing 60 is not exposed and is covered with a cover 70 in a normal use state.

  FIG. 2 is a schematic cross-sectional view of the sphygmomanometer 1A during blood pressure measurement. Referring to FIG. 2, when blood pressure is measured, upper arm 100 is inserted into housing 60 and the elbow is placed on the elbow rest to instruct the start of measurement. The upper arm 100 is compressed and fixed by the living body compression fixing device, and the blood pressure is measured.

  The living body pressure fixing device corresponds to a cuff and is an air bag 13 that is a measurement fluid bag for measuring blood pressure by compressing a measurement site, and is located outside the air bag 13 and inflated by being inflated. An air bag 8 is provided as a fluid bag for pressing the air bag 13 inward to press and fix the air bag 13 to the measurement site of the living body.

FIG. 3 is a block diagram showing a specific example of the configuration of the sphygmomanometer 1A.
Referring to FIG. 3, sphygmomanometer 1A includes air bag 13 and air bag 8, and is connected to air system 20 for measurement and air system 30 for compression and fixing, respectively. The air system 20 includes a pressure sensor 23 for measuring the internal pressure of the air bag 13, a pump 21 for supplying / exhausting air to the air bag 13, and a valve 22. The air system 30 includes the air bag 8. A pressure sensor 33 for measuring the internal pressure, a pump 31 for supplying / exhausting air to / from the air bag 8, and a valve 32 are included.

  The air bag 13 is connected to a pressure sensor 23 for measuring a change in the internal pressure of the air bag 13, a pump 21 for injecting / exhausting air to the air bag 13, and a valve 22. The air bag 8 is connected to a pressure sensor 33 for measuring a change in internal pressure of the air bag 8, a pump 31 for injecting / exhausting air to the air bag 8, and a valve 32.

  Pressure sensors 23 and 33, pumps 21 and 31, and valves 22 and 32 are connected to oscillation circuits 28 and 38, drive circuits 26 and 36, and drive circuits 27 and 37, respectively. The drive circuits 26 and 36 and the drive circuits 27 and 37 are all connected to a CPU (Central Processing Unit) 40 for controlling the entire sphygmomanometer 1A.

  The CPU 40 further includes a display unit 4, an operation unit 3, a memory 6 that stores a program executed by the CPU 40 and serves as a work area when executing the program, and is required for measurement results, control, and calculation. A memory 7 for storing various information, an external interface (I / F) 80 for connecting to an external device and inputting / outputting data, and a temperature sensor 85 for acquiring temperature as information on the surrounding environment A power supply 90 for supplying power to the blood pressure monitor 1A is connected.

  The ambient environment is not limited to the air temperature, and may be other parameters such as atmospheric pressure and humidity, or may be a combination of two or more of these parameters. Alternatively, the ambient temperature information may be acquired from another device through the external I / F 80 without including the temperature sensor 85.

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

  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 22 and 32 are opened / closed.

  The pressure sensors 23 and 33 are capacitance type pressure sensors, and the capacitance values change due to changes in the internal pressure of the air bags 13 and 8, respectively. The pressure sensors 23 and 33 are connected to the oscillation circuits 28 and 38, respectively. The oscillation circuits 28 and 38 convert the signals into oscillation frequency signals corresponding to the capacitance values of the pressure sensors 23 and 33 and input the signals to the CPU 40.

<About the influence of the surrounding environment>
FIG. 4 is a diagram showing the influence of the temperature of the surrounding environment on the relationship between the voltage applied to the pump 21 and the flow rate of air injected into the air bladder 13 by the pump 21 (injection amount per unit time).

  Referring to FIG. 4, the flow rate of air injected into air bag 13 by pump 21 increases as the applied voltage to pump 21 increases regardless of the ambient temperature as the ambient environment. It can be seen that the rate of increase increases and the rate of increase is smaller as the temperature is lower. Therefore, it can be said that the relationship between the voltage applied to the pump 21 and the flow rate of the air injected into the air bladder 13 by the pump 21 depends on the temperature.

  FIG. 5 is a diagram illustrating the influence of atmospheric pressure as an ambient environment on the relationship between the voltage applied to the pump 21 and the flow rate of air injected into the air bladder 13 by the pump 21.

  Referring to FIG. 5, the flow rate of air injected into the air bladder 13 by the pump 21 increases as the applied voltage to the pump 21 increases regardless of the atmospheric pressure as the surrounding environment. It can be seen that the rate of increase increases and the rate of increase is smaller as the atmospheric pressure is higher. Therefore, like the temperature, it can be said that the relationship between the voltage applied to the pump 21 and the flow rate of air injected into the air bladder 13 by the pump 21 depends on the atmospheric pressure.

  As will be described later, in the sphygmomanometer 1A, in a process of injecting a predetermined amount of air into the air bag 13 immediately after the start of the operation of winding the air bag 13 around the measurement site, and pressurizing the air bag 8 for compression. It is determined whether or not the winding degree is appropriate according to the change in the cuff pressure of the air bag 13. Therefore, the CPU 40 applies a predetermined voltage to the pump 21 in order to inject a predetermined amount of air into the air bag 13 immediately after the start of the winding operation.

  However, as shown in FIGS. 4 and 5, the ambient environment such as the air temperature affects the relationship between the voltage applied to the pump 21 and the flow rate of the air injected into the air bladder 13 by the pump 21. For this reason, the amount of air injected immediately after the start of the winding operation varies depending on the surrounding environment. This affects the determination of whether or not the winding degree is appropriate during the winding operation. Therefore, in the sphygmomanometer 1A, the drive of the pump 21 is controlled according to the surrounding environment so that the amount of air injected immediately after the start of the winding operation becomes a predetermined amount.

<Functional configuration>
Referring to FIG. 3 again, in order to realize the above control, the CPU 40 of the sphygmomanometer 1 </ b> A includes an input unit 41 for receiving an input of temperature as ambient environment information from the temperature sensor 85, and the air bag 13. A correction unit 42 for correcting an influence on a measurement result due to a change in the amount of air to be injected depending on the surrounding environment, a calculation unit 43 for calculating a blood pressure value based on a pressure signal from the pressure sensor 23, and measurement Whether or not the air bag 13 is appropriately wound around the measurement site based on the display control unit 44 for performing control to display the result or the like on the display unit 4 and the internal pressure of the air bag 13 during the winding operation And a determination unit 45 for determining the winding state. These are formed in the CPU 40 when the CPU 40 executes a predetermined program stored in the memory 6 based on an operation signal input from the operation unit 3.

  In the CUP 40 of the sphygmomanometer 1A according to the first embodiment, the driving amount of the pump 21 is determined based on the information on the surrounding environment to the correction unit 42, and a control signal is output based on the driving amount to output the pump 21. Further included is a drive control unit 421 for controlling.

  In the memory 7 of the sphygmomanometer 1 </ b> A, a flow rate characteristic based on the ambient temperature around the pump 21 and the applied voltage is stored in advance. The stored flow rate specification may be a function that represents the flow rate, with air temperature and applied voltage as variables, or a table as shown in FIG.

  FIG. 6 is a diagram illustrating a specific example of a table that defines the correspondence between the temperature and the voltage applied to the pump 21. The influence of the air temperature on the relationship between the voltage applied to the pump 21 and the flow rate of the air injected into the air bladder 13 by the pump 21 is the relationship shown in FIG. Therefore, as shown in FIG. 6, the flow rate of air injected into the air bladder 13 by the pump 21 increases in the memory 7 as the voltage applied to the pump 21 increases regardless of the temperature, and the temperature The characteristic that the flow rate of the air injected into the air bladder 13 increases with increasing applied voltage even when the applied voltage is the same is stored.

  The drive control unit 421 refers to the flow rate characteristics stored in the memory 7 during the winding operation, and injects a predetermined amount of air into the air bag 13 immediately after the start of the winding operation at the input air temperature. Therefore, the voltage applied to the pump 21 and the driving time of the pump 21 are calculated. And the drive of the pump 21 is controlled by outputting the control signal according to the calculation result to the drive circuit 26.

<Measurement operation>
FIG. 7 is a flowchart showing the blood pressure measurement operation of the sphygmomanometer 1A. The blood pressure measurement operation shown in the flowchart of FIG. 7 is an operation in the case where the CPU 40 calculates a blood pressure value based on an internal pressure change in the process of reducing the pressure of the air bladder 13. This operation is started when the CPU 40 receives an operation signal when the power switch of the operation unit 3 is pressed, and the CPU 40 reads out and executes a program stored in the memory 6 to execute each unit shown in FIG. It is realized by controlling.

  Referring to FIG. 7, first, after initialization is executed in step S <b> 11, it waits for the user selection switch and the measurement switch to be pressed.

  Next, when the CPU 40 receives an operation signal when the user selection switch is pressed and then an operation signal when the measurement switch is pressed (YES in step S13 and YES in step S15), in step S17. CPU40 performs the winding operation | movement which is an operation | movement for winding the air bag 13 around a user's upper arm which is a measurement site | part appropriately. The operation here will be described later with reference to a flowchart.

  Next, the CPU 40 executes a pressurizing operation for pressurizing the internal pressure of the measurement air bladder 13 until a predetermined internal pressure is reached in step S19. Meanwhile, the CPU 40 monitors the internal pressure of the air bladder 13 obtained from the pressure sensor 23, and determines whether or not the predetermined pressure is set in advance. The predetermined pressure here may be a pressure that is high enough to close the blood vessel. Alternatively, when the measurement result of the selected user is stored in the memory 7, it may be a pressure obtained by adding a predetermined value to the systolic blood pressure value of the user.

  If it is determined that the internal pressure of the air bag 13 has reached the predetermined pressure (YES in step S21), the CPU 40 executes a pressure reducing operation for starting the pressure reduction of the air bags 13, 8 in step S23. The decompression operation is continued until blood pressure calculation (S25) described later is completed.

  In step S25, the CPU 40 calculates a blood pressure value based on the change in the internal pressure of the air bladder 13 during the pressure reducing operation of the air bladder 13 in step S23. When the calculation of the blood pressure value is completed and the blood pressure value is determined (YES in step S27), the CPU 40 ends the pressure reducing operation in step S23, and in step S29, the internal pressure of the air bags 13 and 8 is rapidly reduced. Release the pressure of the living body. And CPU40 performs the operation | movement for displaying the blood pressure value calculated as a measurement result on the display part 4 by step S31.

Thus, a series of operations is completed.
<Winding operation>
FIG. 8 is a flowchart showing the winding operation in step S17. Referring to FIG. 8, when the winding operation is started, in step S <b> 101, CPU 40 receives an input from temperature sensor 85 and acquires the temperature around pump 21.

  In step S103, the CPU 40, based on the acquired air temperature, drives the pump 21 for injecting a predetermined amount of air into the air bag 13, that is, the applied voltage and / or drive time to the pump 21. Is calculated based on the flow rate characteristics of FIG. As an example, when the applied voltage is fixed to a predetermined voltage, the driving time of the pump 21 is calculated by dividing the predetermined amount by the flow rate at the voltage at the ambient temperature of the pump 21. As another example, when the driving time is fixed to a predetermined time, the flow rate obtained by dividing the predetermined amount by the driving time among the flow rates at the applied voltages at the ambient temperature around the pump 21. Identify the closest applied voltage.

  In step S105, the CPU 40 closes the valve 32, and in step S107, outputs a control signal to the drive circuit 26 so as to drive the pump 21 with the applied voltage and / or drive time calculated in step S103. As a result, a predetermined amount of air is injected into the air bag 13 in advance.

  In step S109, the CPU 40 starts injecting air into the air bag 8 after a predetermined amount of air is injected in step S107, and acquires the internal pressure of the air bag 13 at that time as the winding strength. And based on the winding intensity | strength, it is determined whether the winding state to the measurement site | part of the air bag 13 is appropriate.

  As the determination method in step S109, for example, the method disclosed in Japanese Patent Application Laid-Open No. 2005-305028 by the applicant of the present application can be used. That is, as an example, the CPU 40 obtains the internal pressure of the air bladder 13 while pressurizing the air bladder 8 during the winding operation, and the internal pressure is a pressure level indicating an appropriate winding state that has been obtained experimentally in advance, for example. It is determined whether or not a threshold value indicating that a proper winding state has been reached, and the winding operation is terminated.

<Effect of the first embodiment>
By performing such an operation in the sphygmomanometer 1A, it is possible to correct the influence of the surrounding environment on the amount of air injected into the air bag 13 immediately after the start of the winding operation. As a result, a predetermined amount of air, which is defined in advance, is injected into the air bag 13 during the winding operation regardless of the surrounding environment. Accordingly, it is possible to accurately determine whether or not an appropriate winding state is performed during the winding operation while suppressing the influence of the surrounding environment, and an appropriate winding state can be obtained. Thereby, the influence on the measurement accuracy of the surrounding environment can be suppressed, and the measurement accuracy can be improved.

[Second Embodiment]
The device configuration of the sphygmomanometer 1B according to the second embodiment is the same as that of the sphygmomanometer 1A according to the first embodiment.

<About the influence of the surrounding environment>
As described above, since the relationship between the voltage applied to the pump 21 and the flow rate of the air injected into the air bladder 13 by the pump 21 depends on the surrounding environment such as the temperature, a predetermined voltage is applied to the pump 21 in advance. When applied and driven for a specified time, the amount of air injected into the air bladder 13 during the winding operation is affected by the surrounding environment.

  The sphygmomanometer 1A injects air into the air bag 13 immediately after the start of the winding operation by correcting the drive amount of the pump 21 for injecting air into the air bag 13 immediately after the start of the winding operation based on the temperature. It eliminates the influence of the surrounding environment on the air volume. In contrast, the sphygmomanometer 1B eliminates the influence of the surrounding environment on the determination by correcting the threshold value used when determining the winding state based on the internal pressure of the air bag 13 according to the surrounding environment. .

  Specifically, in the sphygmomanometer 1B, as a method of determining the winding state, the relative change amount of the internal pressure of the air bladder 13 in the pressurizing process of the air bladder 8 is disclosed in Japanese Patent Laid-Open No. 2005-305028. A method of determining the winding state based on the above is adopted. This is a determination method regardless of the circumference of the measurement site (arm circumference).

  Specifically, in the sphygmomanometer 1B, a predetermined amount of air is injected into the air bag 13 immediately after the start of the winding operation, and then pressurization of the air bag 8 is started. When the internal pressure of the air bladder 13 reaches a predetermined pressure during the pressurization process, a change in the internal pressure of the air bladder 13 (amount of change in a predetermined time) is further calculated, and the amount of change exceeds the determination threshold value FIT2. It is monitored whether or not it continues for a predetermined determination time DT. Then, when the state continues for the determination time DT, it is determined that an appropriate winding state has been achieved.

  FIG. 9 is a diagram for explaining the determination of the winding state disclosed in Japanese Patent Laid-Open No. 2005-305028. The vertical axis in FIG. 9 represents the amount of change in the internal pressure of the air bag 13 over a predetermined time, and the horizontal axis represents the passage of time. Referring to FIG. 9, at time T, the amount of change in the internal pressure of air bag 13 for a predetermined time reaches determination threshold value FIT2, and thereafter, during determination time DT, the amount of change equal to or greater than determination threshold value FIT2 continues. Yes. Therefore, when the determination time DT elapses from time T, it is determined that an appropriate winding state has been achieved.

  At this time, when the temperature around the pump 21 is higher than the relationship shown in FIG. 6, the pump flow rate at the same applied voltage is increased, so the amount of air injected into the air bag 13 is low. More than. Therefore, when the temperature around the pump 21 is high, the internal pressure of the air bag 13 is higher than in the normal case. Further, when the temperature around the pump 21 is low, the internal pressure of the air bag 13 is lower than in the normal case.

  Therefore, in the sphygmomanometer 1B, when the temperature around the pump 21 is high, the winding state is determined using the determination threshold value FIT3 higher than the determination threshold value FIT2 in the case of the reference temperature, and the pump 21 When the ambient temperature is low, the winding state is determined using the determination threshold value FIT4 lower than the determination threshold value FIT2.

<Functional configuration>
FIG. 10 is a block diagram illustrating a specific example of the configuration of the sphygmomanometer 1B according to the second embodiment. Referring to FIG. 10, CPU 40 of sphygmomanometer 1 </ b> B for realizing the above control has correction unit 42 determine a determination threshold value used for determination of the winding state based on information on the surrounding environment. A first determination unit 422 is included. The determined determination threshold value is used for determination by the determination unit 45.

  The memory 7 of the sphygmomanometer 1B stores in advance a correspondence relationship between the ambient temperature around the pump 21 and the above-described determination threshold value FIT used for determining the winding state. The stored correspondence relationship may be a function representing the determination threshold value FIT with the temperature as a variable, or may be a table that defines the correspondence between the temperature range and the determination threshold value FIT. Specifically, as illustrated in FIG. 9, the memory 7 determines that the reference temperature is higher than the determination threshold FIT2 for the reference temperature, and higher than the determination threshold FIT2 for the temperature higher than the reference temperature. A threshold FIT3 and a determination threshold FIT4 lower than the determination threshold FIT2 are stored for temperatures lower than the reference temperature.

<Winding operation>
The CPU 40 of the sphygmomanometer 1B performs a measurement operation substantially similar to the CPU 40 of the sphygmomanometer 1A shown in FIG. In the sphygmomanometer 1B, the winding operation in step S17 is slightly different.

  FIG. 11 is a flowchart showing the winding operation in the sphygmomanometer 1B. Referring to FIG. 11, CPU 40 of sphygmomanometer 1B replaces the operations of step S103, step S107, and step S109 of the winding operation in sphygmomanometer 1A shown in FIG. 8 with step S103 ′ and step S107. The operation of “and step S109” is performed. Specifically, in step S103 ', the CPU 40 determines the determination threshold value FIT used for determination of the winding state based on the acquired temperature. In step S107 ', the CPU 40 drives the pump 21 with a predetermined driving amount. As a result, an amount of air corresponding to the driving amount is injected into the air bag 13. Then, in step S109 ', the CPU 40 starts injecting air into the air bag 8, and acquires the internal pressure of the air bag 13 at that time and the amount of change in the internal pressure over a predetermined time as the winding strength. Then, it is determined whether or not the winding state is appropriate based on the winding strength and the determination threshold value determined in step S103 '.

<Effects of Second Embodiment>
By performing such an operation in the sphygmomanometer 1B, even when the amount of air injected into the air bag 13 changes immediately after the start of the winding operation according to the surrounding environment, the determination of the winding state is performed. The determination threshold value used is corrected according to the surrounding environment. Accordingly, it is possible to accurately determine whether or not an appropriate winding state is performed during the winding operation while suppressing the influence of the surrounding environment, and an appropriate winding state can be obtained. Thereby, the influence on the measurement accuracy of the surrounding environment can be suppressed, and the measurement accuracy can be improved.

[Third Embodiment]
The device configuration of the sphygmomanometer 1C according to the third embodiment is the same as that of the sphygmomanometer 1A according to the first embodiment.

<About the influence of the surrounding environment>
As described above, since the relationship between the voltage applied to the pump 21 and the flow rate of the air injected into the air bladder 13 by the pump 21 depends on the surrounding environment such as the temperature, a predetermined voltage is applied to the pump 21 in advance. When applied and driven for a specified time, the amount of air injected into the air bag 13 during blood pressure measurement is affected by the surrounding environment.

  FIG. 12 is a diagram showing the relationship between the driving time of the pump 21 and the measured maximum value of the pulse wave amplitude measured for different subjects A, B, and C. FIG. The driving time of the pump 21 represented on the horizontal axis represents the amount of air injected into the air bag 13.

  As shown in FIG. 12, regardless of the characteristics of the subject itself, the longer the driving time of the pump 21, that is, the greater the amount of air injected into the air bag 13, the smaller the maximum value of the pulse wave amplitude tends to be. I understand that.

  FIG. 13 is a diagram showing the relationship between the internal pressure of air bag 13 and the measured pulse wave amplitude. FIG. 13 smoothly connects pulse wave amplitudes measured for each internal pressure of the air bladder 13, and is hereinafter referred to as an envelope. As shown in FIG. 13, it can be seen that the pulse wave amplitude measured by the difference in the internal pressure of the air bladder 13 due to the difference in the amount of air injected into the air bladder 13 is affected. Specifically, the smaller the amount of air injected into the air bag 13, the larger the pulse wave amplitude measured as compared with the larger amount.

  Conventionally, when the maximum value AmpMax of the pulse wave amplitude is measured, the systolic blood pressure value is calculated as an amplitude value obtained by adding a predetermined offset amount γ to a predetermined ratio α of the maximum value of pulse wave amplitude AmpMax, It was calculated | required with the internal pressure of the air bag 13 of the point where an amplitude value and an envelope cross. Similarly, as the diastolic blood pressure value, an amplitude value obtained by adding a predetermined offset amount η to a predetermined ratio β of the maximum value of the pulse wave amplitude AmpMax is calculated, and an air bag at a point where the amplitude value and the envelope intersect It was determined at an internal pressure of 13. The predetermined ratios α and β and the offset amounts γ and η are determined in advance by experiments. In the following description, the calculated amplitude value is also referred to as an “amplitude parameter”.

  However, as shown in FIG. 13, when the amount of air injected into the air bag 13 is small, the pulse wave amplitude is measured to be large, and conversely, when it is large, the pulse wave amplitude is measured to be small. Therefore, the maximum value of the pulse wave amplitude varies depending on the amount of air in the air bag 13. However, as described above, the offset amounts γ and η for calculating the amplitude parameter are constant values independent of the maximum value of the pulse wave amplitude, and thus the calculated amplitude parameter differs depending on the air amount in the air bladder 13. As a result, the blood pressure value obtained by the internal pressure of the air bladder 13 at the intersection of the amplitude parameter and the envelope is also different. That is, by applying a predetermined voltage to the pump 21 in advance and driving it for a specified time, the amount of air injected into the air bag 13 is affected by the surrounding environment, and the blood pressure value calculated thereby is also affected by the surrounding environment. Will receive.

  Therefore, the sphygmomanometer 1C corrects the above-described offset amounts γ and η used for calculating the amplitude parameter according to the surrounding environment, thereby eliminating the influence of the surrounding environment on the calculated amplitude parameter.

<Functional configuration>
FIG. 14 is a block diagram illustrating a specific example of a configuration of a sphygmomanometer 1C according to the third embodiment. Referring to FIG. 14, in CPU 40 of sphygmomanometer 1C for realizing the above control, correction unit 42 has second determination unit for determining the above-described offset amounts γ and η based on information on the surrounding environment. 423 is included. The determined offset amounts γ and η are used for calculation of the blood pressure value in the calculation unit 43.

  In the memory 7 of the sphygmomanometer 1C, a correspondence relationship between the temperature around the pump 21 and the offset amounts γ and η is stored in advance. The stored correspondence relationship may be a function representing the offset amounts γ and η with the temperature T as a variable, or may be a table that defines the correspondence between the range of the temperature T and the offset amounts γ and η. . As an example, when the correspondence between the temperature around the pump 21 and the offset amounts γ, η is stored as a function representing the offset amounts γ, η with the temperature T as a variable, the memory 7 Assuming that the temperature is T and the temperature when the offset amounts γ and η are determined (also referred to as a reference temperature) is TO, γ ′ = γ × (TO / T) as a function representing the corrected offset amounts γ ′ and η ′. ), Η ′ = η × (TO / T) may be stored.

  Alternatively, when the correspondence relationship between the temperature around the pump 21 and the offset amounts γ, η is stored as a table that defines the correspondence between the range of the temperature T and the offset amounts γ, η, the memory 7 is more than the reference temperature. Offset amounts γ 'and η' lower than the offset amounts γ and η for higher temperatures, and offset amounts γ 'and η' higher than the offset amounts γ and η for temperatures lower than the reference temperature. is doing.

<Blood pressure calculation>
The CPU 40 of the sphygmomanometer 1C performs the same measurement operation as the CPU 40 of the sphygmomanometer 1A shown in FIG. In the sphygmomanometer 1C, the operation for blood pressure calculation in step S25 is slightly different.

  FIG. 15 is a flowchart showing an operation for blood pressure calculation in the sphygmomanometer 1C. Referring to FIG. 15, when the operation for blood pressure calculation starts, CPU 40 of sphygmomanometer 1C receives an input from temperature sensor 85 and acquires temperature T around pump 21 in step S201.

  In step S203, the CPU 40 refers to the correspondence between the temperature around the pump 21 stored in the memory 7 and the offset amount based on the acquired temperature, and the offset amount γ corresponding to the acquired temperature T. Determine ', η'.

  The CPU 40 monitors the internal pressure of the air bladder 13 and acquires the pulse wave amplitude superimposed on the pressure change. When the maximum value (AmpMax) is acquired in step S205, in step S207, the CPU 40 calculates AmpMax × α + γ ′ and AmpMax × β + η ′ by calculating AmpMax × α + γ ′. In step S209, the CPUI 40 determines the internal pressure of the air bladder 13 at the intersection of the envelope obtained from the change in the internal pressure of the air bladder 13 and the measured pulse wave amplitude and the amplitude parameter, respectively, as a systolic blood pressure value and a diastole. Obtained as a blood pressure value.

<Other examples>
As another example of the blood pressure value calculation method, an amplitude parameter obtained by multiplying a systolic blood pressure value by a predetermined ratio α of the maximum value of the pulse wave amplitude AmpMax and a predetermined coefficient γ intersects with an envelope. The air pressure at the point where the amplitude parameter obtained by multiplying the predetermined pressure β of the maximum value AmpMax of the pulse wave amplitude by the predetermined coefficient β and the envelope intersect the internal pressure of the air bag 13 and the diastolic blood pressure value. There is also a method to get as. In this case, the memory 7 stores γ ′ = γ × T and η ′ = η × T as functions representing the corrected coefficients γ ′ and η ′ as the correspondence relationship between the temperature around the pump 21 and the coefficients. May be.

  Even in this case, the CPU 40 determines coefficients γ ′ and η ′ according to the temperature T around the pump 21 and calculates the blood pressure value in substantially the same operation as that shown in FIG.

<Effect of the third embodiment>
By performing such an operation in the sphygmomanometer 1C, it is used to calculate the blood pressure value even when the amount of air injected into the air bag 13 during blood pressure measurement changes according to the surrounding environment. The offset amount or coefficient for obtaining the amplitude parameter is corrected according to the surrounding environment. Thereby, since the influence of the surrounding environment on the amplitude parameter is suppressed, the influence of the surrounding environment on the calculated blood pressure value is suppressed. Thereby, the influence on the measurement accuracy of the surrounding environment can be suppressed, and the measurement accuracy can be improved.

[Fourth Embodiment]
The device configuration of the sphygmomanometer 1D according to the fourth embodiment is the same as that of the sphygmomanometer 1A according to the first embodiment.

<About the influence of the surrounding environment>
The sphygmomanometer 1C corrects the offset amount for obtaining the amplitude parameter used for calculating the blood pressure value according to the surrounding environment, thereby affecting the influence of the surrounding environment on the amount of air injected into the air bag 13 during blood pressure measurement. Is to be eliminated. On the other hand, the sphygmomanometer 1D corrects the calculated blood pressure value according to the surrounding environment, thereby eliminating the influence of the surrounding environment on the measurement result.

  Specifically, referring again to FIG. 13, the larger the air temperature around the pump 21 and the greater the amount of air injected into the air bladder 13, the smaller the measured pulse wave amplitude becomes. As the air temperature is lower and the amount of air injected into the air bag 13 is smaller, the pulse wave amplitude generally increases. Therefore, when the amplitude parameter is calculated using the same offset amounts γ and η, the smaller the maximum value of the pulse wave amplitude, that is, the larger the amount of air injected into the air bag 13, the larger the amplitude parameter corresponds to the maximum value of the pulse wave amplitude. The ratio increases. Therefore, in the above-described method, the blood pressure value is calculated to be smaller as the amount of air injected into the air bag 13 is larger.

  Therefore, in the sphygmomanometer 1D, when the temperature around the pump 21 is high, the correction is performed using a correction amount ΔP that increases the calculated blood pressure value P, and when the temperature around the pump 21 is low. Correction is performed using a correction amount ΔP that lowers the calculated blood pressure value P to obtain a systolic blood pressure value SYS and a diastolic blood pressure value DIA.

<Functional configuration>
FIG. 16 is a block diagram illustrating a specific example of the configuration of a sphygmomanometer 1D according to the fourth embodiment. Referring to FIG. 16, CPU 40 of sphygmomanometer 1D for realizing the above control has correction unit 42 to determine correction amount ΔP of calculated blood pressure value P based on information on the surrounding environment. A third determination unit 424 is included. Then, the correction unit 42 corrects the blood pressure value P calculated by the calculation unit 43 with the correction amount ΔP to obtain a measurement result.

  In the memory 7 of the sphygmomanometer 1D, a correspondence relationship between the temperature around the pump 21 and the correction amount ΔP is stored in advance. The stored correspondence relationship may be a function representing the correction amount ΔP with the temperature T as a variable, or may be a table that defines the correspondence between the range of the temperature T and the correction amount ΔP. Specifically, the memory 7 stores the correction amount ΔP that increases the calculated blood pressure value P for temperatures higher than the reference temperature, and the calculated blood pressure value for temperatures lower than the reference temperature. A correction amount ΔP that lowers P is stored.

<Blood pressure calculation>
The CPU 40 of the sphygmomanometer 1D performs a measurement operation substantially similar to the CPU 40 of the sphygmomanometer 1A shown in FIG. In the sphygmomanometer 1D, the operation for calculating the blood pressure in step S25 is slightly different.

  FIG. 17 is a flowchart showing an operation for blood pressure calculation in the sphygmomanometer 1D. Referring to FIG. 17, CPU 40 of sphygmomanometer 1D operates in steps S203 ′ and S207 ′ instead of the operations in steps S203 and S207 for the blood pressure calculation in sphygmomanometer 1C shown in FIG. In addition, the operation of step S210 is performed. Specifically, in step S203 ′, the CPU 40 refers to the correspondence between the temperature around the pump 21 stored in the memory 7 and the correction amount based on the acquired temperature, and the contraction corresponding to the acquired temperature T. A correction amount ΔP1 for correcting the systolic blood pressure value and a correction amount ΔP2 for correcting the diastolic blood pressure value are determined. In step S207 ′, the CPU 40 performs normal calculations such as AmpMax × α + γ and AmpMax × β + η to calculate the amplitude parameter, and in step S209, the envelope obtained from the change in the internal pressure of the air bladder 13 and the measured pulse wave amplitude. And the internal pressures P1 and P2 of the air bladder 13 at the intersections of the amplitude parameters.

  In step S210, the CPU 40 corrects the obtained internal pressures P1, P2 using the correction amounts ΔP1, ΔP2, respectively, to obtain a systolic blood pressure value SYS and a diastolic blood pressure value DIA.

<Effect of the fourth embodiment>
By performing such an operation in the sphygmomanometer 1D, even if the amount of air injected into the air bag 13 during blood pressure measurement changes according to the surrounding environment, the calculated blood pressure value is displayed in the surrounding environment. It is corrected according to. Thereby, the influence of the surrounding environment on the calculated blood pressure value is suppressed. Thereby, the influence on the measurement accuracy of the surrounding environment can be suppressed, and the measurement accuracy can be improved.

[Modification]
The first to fourth embodiments described above may be performed separately, or one of the first embodiment and the second embodiment. And the correction of either one of the third embodiment and the fourth embodiment may be combined. By combining these, it is possible to improve the accuracy of the determination of the winding state and the accuracy of the calculated blood pressure value.

  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, 1A, 1B, 1C, 1D Blood pressure monitor, 2 body, 3 operation unit, 4 display unit, 5 measurement unit, 6, 7 memory, 8, 13 air bag, 20, 30 air system, 21, 31 pump, 22 , 32 Valve, 23, 33 Pressure sensor, 26, 27, 36, 37 Drive circuit, 28, 38 Oscillator circuit, 41 Input section, 42 Correction section, 43 Calculation section, 44 Display control section, 45 Determination section, 60 Housing, 70 cover, 85 temperature sensor, 90 power supply, 100 upper arm, 421 drive control unit, 422 first determination unit, 423 second determination unit, 424 third determination unit.

Claims (8)

A fluid bag for wrapping around the subject's measurement site;
A sensor for detecting an internal pressure of the fluid bag;
Adjusting means for injecting / extracting fluid into the fluid bag;
An acquisition means for acquiring information on the surrounding environment of the blood pressure monitor;
Control means,
The control means includes
The adjusting means is controlled so that a predetermined amount of fluid is injected into the fluid bag immediately after the measurement operation is started, and the winding around the measurement site is performed based on the amount of change in internal pressure when the fluid bag is wound around the measurement site. After the attachment strength is detected and the fluid bag is wound around the measurement site, the blood pressure value of the subject is calculated based on a change in the internal pressure of the fluid bag under control of increasing or reducing the internal pressure of the fluid bag Calculating means for
An electronic sphygmomanometer, comprising: correction means for correcting an influence caused by a change in the amount of fluid injected into the fluid bag when the fluid bag is wound around the measurement site according to the acquired surrounding environment .   The electronic sphygmomanometer according to claim 1, wherein the correction unit determines an amount of fluid to be injected into the fluid bag immediately after the measurement operation starts based on information on the surrounding environment.   The electronic sphygmomanometer according to claim 1, wherein the correction unit determines a threshold value used in a process of detecting a winding degree with respect to the measurement site based on information on the surrounding environment.   The electronic sphygmomanometer according to claim 1, wherein the correction unit determines a parameter used in a process of calculating a blood pressure value of the subject based on information on the surrounding environment.   The electronic sphygmomanometer according to claim 1, wherein the correction unit determines a correction amount of the blood pressure value calculated by the calculation unit based on the information on the surrounding environment, and corrects the blood pressure value.   The electronic sphygmomanometer according to claim 1, wherein the acquisition unit includes a sensor for measuring the surrounding environment.   The electronic sphygmomanometer according to claim 1, wherein the acquisition unit includes a unit for communicating with another device, and acquires the surrounding environment from the other device.   The electronic sphygmomanometer according to claim 1, wherein the ambient environment is an ambient temperature around the adjustment unit.

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