JP2022116833A - Blood pressure measuring device and control method - Google Patents

Abstract

To provide a blood pressure measuring device and a control method capable of raising the pressure of a cuff wound around a subject at a target pressure raising speed at an initial stage after measurement of the subject's blood pressure is started.SOLUTION: A blood pressure measuring device measures blood pressure of a subject while the pressure in a cuff wound around a subject is raised in a blood pressure measurement range. The blood pressure measuring device includes: a pressure raising part for executing a pressure raising operation for raising the pressure in the cuff; a calculation part for calculating a pressure raising speed in the cuff before the actual pressure in the cuff is brought into the blood pressure measurement range; and a control part for controlling the pressure raising operation with a predetermined amount of control according to the calculated pressure raising speed so that the actual pressure raising speed in the cuff is converged to a target pressure raising speed when the actual pressure in the cuff is brought into the blood pressure measurement range.SELECTED DRAWING: Figure 1

Description

The present invention relates to a blood pressure measuring device and control method.

In recent years, blood pressure measuring devices capable of automatically measuring blood pressure have become widely used in general households and public places, and are used as part of health care. As described above, various blood pressure measuring devices have been proposed as devices that can be easily used not only by medical institutions but also by ordinary people.

As a method of blood pressure measurement by a blood pressure measuring device, for example, after the pressure in the cuff wrapped around the blood pressure measurement site of the subject is raised to a pressure higher than the systolic blood pressure (SYS) by a pump or the like, constant speed exhaust (for example , 3 to 5 mmHg/sec), blood pressure (for example, systolic blood pressure, diastolic blood pressure) based on the pulse wave signal superimposed on the sensor detection signal (pressure signal) obtained by the pressure sensor A step-down measurement method for measuring is used (see, for example, Patent Document 1).

In addition, a pressurization measurement system is used for the purpose of reducing the burden on the blood pressure measurement site by shortening the blood pressure measurement time compared to the pressure reduction measurement system. In this pressurization measurement method, the subject's blood pressure is measured based on the pulse wave signal superimposed on the sensor detection signal obtained by the pressure sensor in the process of increasing the pressure in the cuff to, for example, 160 to 190 mmHg.

In both the pressure-lowering measurement method and the pressure-boosting measurement method, the volume change due to the blood flow in the cuff is detected as the amplitude change of the pressure inside the cuff, and the blood pressure is measured based on the detected amplitude change. The amount of change in the amplitude of the pressure in the cuff differs depending on the blood pressure value, the volume of the cuff, the blood flow of the subject, etc., and is about 1/10 mmHg when small.

JP-A-2002-136491

By the way, in the pressurization measurement method, even if there is a difference in the ease of inflation of the cuff due to differences in the size (capacity) of the cuff wrapped around the patient's blood pressure measurement site and the way the cuff is wrapped, the correct pulse wave signal can be obtained. In order to acquire and accurately measure the blood pressure of the subject, it is necessary to increase the pressure in the cuff at a predetermined target pressure increase rate (increase amount per unit time). Therefore, conventionally, feedback control is performed to control the pressure increase operation in the cuff according to the difference between the actual pressure increase speed of the cuff and the target pressure increase speed.

However, feedback control generally has a response delay with respect to a control signal, and even if the control signal is output, the boost speed in the cuff does not change immediately. In addition, considering the response delay, if the control amount is increased so that the actual pressure increase speed of the cuff converges to the target pressure increase speed in a short period of time, the actual pressure increase speed fluctuates greatly and goes back and forth across the target value. Furthermore, fluctuations occur in the pulse wave signal superimposed on the sensor detection signal obtained in the process of increasing the pressure of the cuff. As a result, it becomes difficult to obtain a correct pulse wave signal and accurately measure the blood pressure of the subject.

Therefore, it is conceivable to reduce the control amount in order to suppress the fluctuation of the pulse wave signal superimposed on the sensor detection signal obtained in the process of increasing the pressure of the cuff. However, in this case, it takes a long time for the actual pressure increase rate of the cuff to converge to the target pressure increase rate. was there. In particular, if the actual pressure rise rate of the cuff does not converge to the target pressure rise rate when the actual pressure in the cuff is low, a correct pulse wave signal of the subject cannot be sufficiently acquired, and the lowest pressure of the subject cannot be obtained. Blood pressure cannot be measured in the first place, or the diastolic blood pressure cannot be measured with high accuracy.

An object of the present invention is to provide a blood pressure measuring device and a control method capable of increasing the pressure of a cuff wrapped around a subject at a target pressure increasing rate in the initial stage after the start of blood pressure measurement of the subject. be.

A blood pressure measuring device according to the present invention comprises:
A blood pressure measurement device that measures the blood pressure of the subject while the pressure in the cuff wrapped around the subject is increased within a blood pressure measurement range,
a boosting unit that performs a boosting operation to boost the pressure in the cuff;
a calculation unit that calculates a pressure increase rate in the cuff before the pressure in the cuff enters the blood pressure measurement range;
The pressure increase operation is performed by a predetermined control amount according to the calculated pressure increase rate so that the pressure increase rate in the cuff converges to the target pressure increase rate when the actual pressure in the cuff enters the blood pressure measurement range. a control unit that controls
Prepare.

A control method according to the present invention includes:
A control method in a blood pressure measuring device for measuring the blood pressure of a subject while the pressure in a cuff wrapped around the subject is increased within a blood pressure measurement range,
before the pressure in the cuff enters the blood pressure measurement range, calculating the pressure increase rate in the cuff;
The pressure increase operation is controlled by a predetermined control amount according to the calculated pressure increase rate so that the pressure increase rate in the cuff converges to a target pressure increase rate when the pressure in the cuff enters the blood pressure measurement range. .

According to the present invention, the pressure of the cuff wrapped around the subject can be increased at the target pressure increase rate in the initial stage after the start of blood pressure measurement of the subject.

1 is a block diagram showing a configuration example of a blood pressure measurement device according to this embodiment; FIG. FIG. 10 is a diagram showing time-series changes in the pressure in the cuff that is increased when the subject's blood pressure is measured. 4 is a flowchart showing an example of control operation of the blood pressure measuring device; FIG. 10 is a diagram showing time-series changes in the pressure in the cuff that is increased when the subject's blood pressure is measured. FIG. 10 is a diagram showing time-series changes in the pressure in the cuff that is increased when the subject's blood pressure is measured.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration example of a blood pressure measurement device 100 according to this embodiment. A blood pressure measuring device 100 is used, for example, in a medical facility such as a hospital to measure the blood pressure of a subject (eg, patient). In the present embodiment, blood pressure measurement device 100 uses a pressurization measurement method for the purpose of reducing the burden on the blood pressure measurement site by shortening the blood pressure measurement time compared to the blood pressure measurement method. That is, the blood pressure measurement device 100 increases the pressure in the blood pressure measurement cuff 120 wrapped around the subject, and measures the blood pressure of the subject while the pressure is increased within the blood pressure measurement range.

FIG. 2 is a diagram showing, by a solid line L, time series changes in the pressure in the blood pressure measurement cuff 120 that is increased when the subject's blood pressure is measured. As shown in FIG. 2, in the process of increasing the pressure (cuff pressure) in the blood pressure measurement cuff 120 to, for example, 160 mmHg, the blood pressure measurement device 100 responds to the sensor detection signal obtained by the pressure detection unit 106 that detects the pressure. The subject's blood pressure is measured based on the superimposed pulse wave signal. In the example shown in FIG. 2, the pulse wave signal is superimposed on the sensor detection signal when the cuff pressure is, for example, 70 to 130 mmHg.

As shown in FIG. 1 , blood pressure measurement device 100 includes control section 102 , pressure increasing section 104 , pressure detection section 106 , filter section 108 , storage section 110 , operation section 112 and display section 114 .

A blood pressure measurement cuff 120 (compression band) is connected to the blood pressure measurement device 100 . The blood pressure measurement cuff 120 is formed in a longitudinal shape from a strip-shaped cloth bag containing an inflatable synthetic rubber inflatable bag, for example, and is provided inside the ends in the longitudinal direction and outside the middle part in the longitudinal direction. It is constructed so that it can be wound around the subject's blood pressure measurement site (for example, the upper arm) using a fastener. The blood pressure measurement cuff 120 functions as the "cuff" of the present invention.

Blood pressure measurement cuff 120 is integrally provided with a flexible tube (hose), and a connector provided at the tip of the flexible tube is detachably inserted into a socket provided in blood pressure measurement device 100. , are connected to the boosting unit 104 and the pressure detecting unit 106 in the blood pressure measuring device 100 by a common air flow path.

The control unit 102 includes, for example, an arithmetic processing device such as a CPU (Central Processing Unit) and a memory device such as a RAM (Random Access Memory). The control unit 102 develops a program stored in the storage unit 110 (for example, ROM (Read Only Memory) or the like) in a memory device and executes the program by the arithmetic processing unit, thereby executing overall control of the blood pressure measurement device 100 . . Note that the control unit 102 functions as a “calculation unit” and a “control unit” of the present invention.

When the subject's blood pressure is measured, the pressure increasing section 104 is controlled by the control section 102 to increase the pressure in the blood pressure measurement cuff 120 wrapped around the subject. In this embodiment, the boosting section 104 includes an air supply section 104A and an exhaust section 104B.

The air supply unit 104</b>A is a pump that supplies air to the blood pressure measurement cuff 120 , that is, increases the pressure in the blood pressure measurement cuff 120 by supplying air into the blood pressure measurement cuff 120 . In the present embodiment, known duty control based on the ON/OFF time ratio of the air supply operation is adopted as the control of the air supply unit 104A. That is, the air supply unit 104A changes the amount of air supplied to the blood pressure measurement cuff 120 according to the duty ratio (eg, 0 to 100%) indicated by the duty signal output from the control unit 102. FIG. The air supply unit 104A increases the amount of air supplied to the blood pressure measurement cuff 120 as the duty ratio increases toward 100%, while supplying air to the blood pressure measurement cuff 120 as the duty ratio decreases toward 0%. reduce the amount.

The exhaust unit 104B is a flow control valve that reduces the pressure in the blood pressure measurement cuff 120 by exhausting the blood pressure measurement cuff 120, that is, discharging the air in the blood pressure measurement cuff 120. FIG. A flow control valve as the exhaust part 104B can be realized by, for example, an electromagnetic valve using a solenoid. In the present embodiment, known duty control based on the ON/OFF time ratio of the exhaust operation is adopted as the control of the exhaust unit 104B. That is, the exhaust unit 104B changes the exhaust amount for the blood pressure measurement cuff 120 according to the duty ratio (eg, 0 to 100%) indicated by the duty signal output from the control unit 102. As the duty ratio increases toward 100%, the exhaust unit 104B reduces the opening degree of the flow control valve to reduce the exhaust amount for the blood pressure measurement cuff 120, while the duty ratio decreases toward 0%. The opening degree of the flow control valve is increased to increase the exhaust volume for blood pressure measurement cuff 120 .

Air is supplied from the pressurizing unit 104 to the blood pressure measurement cuff 120 according to the difference between the amount of air supplied by the air supply unit 104A and the amount of exhaust air by the exhaust unit 104B (=air supply amount−exhaust amount), resulting in blood pressure measurement. The pressure in the cuff 120 increases.

The pressure detection unit 106 is, for example, a pressure-electricity conversion sensor using a piezo element or the like. Output. Since the pressure in the blood pressure measurement cuff 120 changes due to the pulsation of the subject around which the blood pressure measurement cuff 120 is wrapped, the sensor output signal includes a volume pulse wave signal component (hereinafter simply referred to as a “pulse wave signal”). say) are superimposed. The sensor output signal is sampled at a predetermined frequency by an AD converter (not shown) and converted into digital data.

Filter section 108 extracts a pulse wave signal from the sensor output signal output from pressure detection section 106 and outputs the extracted pulse wave signal to control section 102 . Specifically, the filter unit 108 can extract the pulse wave signal from the sensor output signal by using a band-pass filter that passes general pulse frequencies.

Further, the filter unit 108 generates a pressure signal by removing the pump noise component (air supply unit 104A) and the pulse wave signal from the sensor output signal output from the pressure detection unit 106 and outputs the pressure signal to the control unit 102 . Specifically, the filter unit 108 can generate the pressure signal by using a low-pass filter that removes AC components such as pump noise components and pulse wave signals from the sensor output signal.

When the subject's blood pressure is measured, the control unit 102 controls the boosting operation of the boosting unit 104 (air supply unit 104A, exhaust unit 104B) based on the pressure signal output from the filter unit 108 .

When the blood pressure of the subject is measured, the control unit 102 applies a known oscillometric algorithm to measure the blood pressure value. Control unit 102 monitors changes in pulse wave amplitude based on changes in pulse wave amplitude obtained from the pressure signal and pulse wave signal output from filter unit 108 and the pressure in blood pressure measurement cuff 120, The cuff pressure at a predetermined timing while the pulse wave amplitude is increasing is measured as the diastolic blood pressure, and the cuff pressure at a predetermined timing while the pulse wave amplitude is decreasing is measured as the systolic blood pressure.

After measuring the systolic blood pressure and the diastolic blood pressure, the control unit 102 stores the values of the systolic blood pressure and the diastolic blood pressure in the storage unit 110 as measurement data. After the blood pressure measurement of the subject is completed, the control unit 102 controls the pressure increasing unit 104 (the air supply unit 104A and the exhaust unit 104B) to stop the supply of air into the blood pressure measurement cuff 120, and the blood pressure is increased. Allow all air in the measuring cuff 120 to be expelled.

The storage unit 110 is a storage device that stores information about measurement data (such as information about a subject) and measurement data. Storage unit 110 may be configured to use a recording medium removable from blood pressure measurement device 100, such as a memory card.

The operation unit 112 includes, for example, keys, switches, and buttons, and receives instructions and settings from the user. The operation unit 112 includes, for example, a power button/switch, a switch/button for instructing the start of blood pressure measurement, a switch/button for instructing to stop blood pressure measurement in progress, and the like. The control unit 102 monitors the operation of the operation unit 112 and performs an operation according to the detected operation.

The display unit 114 is composed of, for example, a dot-matrix display such as an LCD, an LED lamp, and the like, and receives control from the control unit 102 to display the operating state of the blood pressure measurement device 100, measurement results, guidance, and the like. It should be noted that blood pressure measurement apparatus 100 may include other output devices such as a speaker and a printer in place of display unit 114 or in addition to display unit 114 .

By the way, in the pressurization measurement method used as a method of blood pressure measurement by the blood pressure measurement device 100, the size (capacity) of the blood pressure measurement cuff 120 wrapped around the blood pressure measurement site of the subject and the size (capacity) of the blood pressure measurement cuff 120 Even if there is a difference in the easiness of swelling (also referred to as compliance) of the blood pressure measurement cuff 120 due to a difference in the winding method, in order to acquire a correct pulse wave signal and accurately measure the blood pressure of the subject, the predetermined target It is necessary to pressurize the blood pressure measurement cuff 120 at a pressurization rate (amount of pressurization per unit time). Therefore, conventionally, feedback control is performed to control the pressure increase operation in blood pressure measurement cuff 120 according to the difference (deviation) between the actual pressure increase speed of blood pressure measurement cuff 120 and the target pressure increase speed.

However, feedback control generally has a response delay with respect to a control signal, and even if the control signal is output, the rate of pressure increase in blood pressure measurement cuff 120 does not change immediately. In addition, if the control amount is increased in consideration of the response delay so that the actual pressure increase rate in the blood pressure measurement cuff 120 converges to the target pressure increase rate in a short period of time, the actual pressure increase rate fluctuates greatly and straddles the target value. Fluctuations occur in the pulse wave signal superimposed on the sensor detection signal obtained in the process of increasing the pressure of the cuff 120 for blood pressure measurement. As a result, it becomes difficult to obtain a correct pulse wave signal and accurately measure the blood pressure of the subject.

Therefore, it is conceivable to reduce the control amount in order to suppress the fluctuation of the pulse wave signal superimposed on the sensor detection signal obtained in the process of increasing the pressure of the blood pressure measurement cuff 120 . However, in this case, it takes a long time for the actual pressure increase rate in the blood pressure measurement cuff 120 to converge to the target pressure increase rate, and it is not possible to increase the pressure at the target pressure increase rate in the initial stage after the start of blood pressure measurement of the subject. There was a problem of difficulty. In particular, if the actual pressure increase rate in blood pressure measurement cuff 120 does not converge to the target pressure increase rate in a stage where the actual pressure in blood pressure measurement cuff 120 is low, it is difficult to sufficiently obtain a correct pulse wave signal of the subject. Therefore, the diastolic blood pressure of the subject cannot be measured in the first place, or the diastolic blood pressure cannot be measured with high accuracy.

Therefore, in the present embodiment, blood pressure measurement device 100 can increase blood pressure measurement cuff 120 wrapped around the subject at a target pressure increase rate in the initial stage after the start of blood pressure measurement of the subject. It is configured.

Specifically, based on the pressure signal output from filter section 108, control section 102 of blood pressure measurement apparatus 100 controls blood pressure measurement pressure before the actual pressure in blood pressure measurement cuff 120 enters the blood pressure measurement range. A rate of pressure increase within the cuff 120 is calculated. Then, when the actual pressure in blood pressure measurement cuff 120 enters the blood pressure measurement range, control unit 102 adjusts the pressure increase rate to the calculated pressure increase rate so that the pressure increase rate in blood pressure measurement cuff 120 converges to the target pressure increase rate. The boosting operation of the boosting unit 104 is controlled by a predetermined control amount corresponding to the control amount.

The blood pressure measurement range is determined based on the blood pressure measurement performance of the blood pressure measurement device 100, and means a range in which the blood pressure of the subject around which the blood pressure measurement cuff 120 is wrapped can be measured correctly. The target pressure increase rate is determined based on the blood pressure measurement performance of the blood pressure measurement device 100, and is set in advance so that the blood pressure of the subject around whom the blood pressure measurement cuff 120 is wrapped can be measured correctly. The pressure rise rate (eg, 5-10 mmHg/sec).

Next, an example of the control operation of the blood pressure measuring device 100 (corresponding to the "control method" of the present invention) will be described with reference to the flowchart of FIG. The process in step S100 is executed, for example, by performing an operation on the operation unit 112 to instruct the start of blood pressure measurement while the blood pressure measurement cuff 120 is wrapped around the blood pressure measurement site of the subject. be done.

First, the control unit 102 controls the pressure increasing unit 104 so as to start the pressure increasing operation for increasing the pressure in the blood pressure measurement cuff 120 with a predetermined operation amount (step S100). In the present embodiment, control unit 102 outputs a duty signal indicating a duty ratio of 100% to air supply unit 104A, thereby causing blood pressure measurement cuff 120 to supply the maximum amount of air. Further, the control unit 102 outputs a duty signal indicating a duty ratio of 100% to the exhaust unit 104B, thereby completely closing the flow control valve and preventing the blood pressure measurement cuff 120 from exhausting. By starting the pressure-increasing operation for increasing the pressure in the blood pressure measurement cuff 120 with a predetermined amount of movement, the size (capacity) of the cuff wrapped around the blood pressure measurement site of the subject, and the difference in the easiness of inflating the cuff. appears as a difference in pressure increase rate within the blood pressure measurement cuff 120 in the initial stage after the start of blood pressure measurement of the subject. It should be noted that if the difference in the ease of inflating the cuff clearly appears as the difference in the rate of pressure increase in the blood pressure measurement cuff 120, the control unit 102 does not necessarily supply the blood pressure measurement cuff 120 with the maximum air supply amount. is not necessary, and a duty signal indicating, for example, 60% as a duty ratio may be output to the air supply unit 104A.

Next, based on the pressure signal output from the filter unit 108, the control unit 102 determines whether or not the actual pressure inside the blood pressure measurement cuff 120 has reached a predetermined pressure before entering the blood pressure measurement range. (Step S120). As a result of determination, if the actual pressure in blood pressure measurement cuff 120 has not reached the predetermined pressure (step S120, NO), the process returns to step S120. The predetermined pressure is set to, for example, half the lower limit of the blood pressure measurement range.

On the other hand, when the actual pressure in blood pressure measurement cuff 120 reaches the predetermined pressure (step S120, YES), control unit 102 controls pressure in blood pressure measurement cuff 120 based on the pressure signal output from filter unit 108. is calculated as the initial boost speed (step S140).

Next, the control unit 102 determines whether or not the initial boost speed is equal to or higher than the first boost speed (step S160). As a result of the determination, if the initial pressure increase rate is equal to or higher than the first pressure increase rate (step S160, YES), control unit 102 controls blood pressure measurement cuff 120 to increase blood pressure measurement cuff 120 when the actual pressure in blood pressure measurement cuff 120 enters the blood pressure measurement range. The boosting operation of the boosting unit 104 is controlled with a predetermined first control amount so that the actual boosting speed in 120 converges to the target boosting speed (step S180). Thereafter, the process transitions to step S240.

In the present embodiment, controlling the boosting operation of the boosting unit 104 with a predetermined first control amount means reducing the duty ratio that defines the air supply amount of the air supply unit 104A from 100% to 60% by 40%, This means that the duty ratio that defines the exhaust amount of the exhaust unit 104B is reduced by 50% from 100% to 50%. That is, the control unit 102 reduces the amount of air supplied to the blood pressure measurement cuff 120 by outputting a duty signal indicating a duty ratio of 60% to the air supply unit 104A. Further, the control unit 102 outputs a duty signal indicating a duty ratio of 50% to the exhaust unit 104B, thereby opening the flow control valve halfway and causing the blood pressure measurement cuff 120 to exhaust. By performing abrupt control in this manner before the actual pressure in blood pressure measurement cuff 120 enters the blood pressure measurement range, the actual pressure increase rate in blood pressure measurement cuff 120 can quickly approach the target pressure increase rate. can. Experiments and simulations were performed with various values of the initial pressure increase rate, which is equal to or higher than the first pressure increase rate, and the predetermined first control amount was determined when the actual pressure in the blood pressure measurement cuff 120 entered the blood pressure measurement range. is a control amount set in advance so that the actual rate of pressure increase in blood pressure measurement cuff 120 converges to the target rate of pressure increase.

Returning to the determination process of step S160, if the initial pressure increase speed is smaller than the first pressure increase speed (step S160, NO), the control unit 102 determines whether or not the initial pressure increase speed is greater than the second pressure increase speed (step S200). As a result of the determination, if the initial pressure increase rate is greater than the second pressure increase rate (step S200, YES), control unit 102 controls blood pressure measurement cuff 120 to increase blood pressure measurement cuff 120 when the actual pressure in blood pressure measurement cuff 120 enters the blood pressure measurement range. The boosting operation of the boosting section 104 is controlled with a predetermined second control amount so that the actual boosting speed in the range converges to the target boosting speed (step S220). Thereafter, the process transitions to step S240. It should be noted that the first pressure-increase speed and the second pressure-increase speed correspond to the "plurality of predetermined pressure-increase speeds" of the present invention.

In the present embodiment, controlling the boosting operation of the boosting unit 104 with a predetermined second control amount means reducing the duty ratio that defines the air supply amount of the air supply unit 104A from 100% to 90% by 10%, This means that the duty ratio that defines the exhaust amount of the exhaust unit 104B is maintained at 100%. That is, the control unit 102 reduces the amount of air supplied to the blood pressure measurement cuff 120 by outputting a duty signal indicating a duty ratio of 90% to the air supply unit 104A. Further, the control unit 102 continues to output a duty signal indicating a duty ratio of 100% to the exhaust unit 104B, thereby preventing the blood pressure measurement cuff 120 from exhausting while the flow control valve is completely closed. In this way, by performing relatively abrupt control before the actual pressure in blood pressure measurement cuff 120 enters the blood pressure measurement range, the actual pressure increase rate of blood pressure measurement cuff 120 can quickly approach the target pressure increase rate. can be done. Experiments and simulations were conducted while varying the value of the initial pressure rise rate, which is smaller than the first pressure rise rate and larger than the second pressure rise rate, and the actual pressure in the blood pressure measurement cuff 120 was determined to be the predetermined second control amount. This control amount is set in advance so that the actual rate of pressure increase within the blood pressure measurement cuff 120 converges to the target rate of pressure increase when entering the blood pressure measurement range.

Returning to the determination process of step S200, if the initial pressure increasing speed is equal to or lower than the second pressure increasing speed (step S200, NO), control unit 102 controls the pressure increasing operation of pressure increasing unit 104 with a predetermined control amount. do not have. Since the actual pressure increase rate within the blood pressure measurement cuff 120 is relatively close to the target pressure increase rate, the actual pressure within the blood pressure measurement cuff 120 can be adjusted to the blood pressure measurement range by controlling the pressure increase section 104 while maintaining a predetermined amount of operation. This is because it is assumed that the actual pressure increase rate in the blood pressure measurement cuff 120 converges to the target pressure increase rate when entering. As described above, the control unit 102 controls the control amount of the air supply in the air supply unit 104A and the exhaust air in the exhaust unit 104B based on the result of comparison between the initial pressure increase speed, the first pressure increase speed, and the second pressure increase speed. Change the amount and combination. Thereafter, the process transitions to step S240.

In step S240, based on the pressure signal output from the filter unit 108, the control unit 102 causes the pressure increasing operation of the pressure increasing unit 104 according to the deviation between the actual pressure increasing speed in the blood pressure measurement cuff 120 and the target pressure increasing speed. Control. Specifically, the control unit 102 controls the air supply amount of the air supply unit 104A and the exhaust amount of the exhaust unit 104B so as to eliminate the deviation between the actual pressure increase rate in the blood pressure measurement cuff 120 and the target pressure increase rate. . In this way, by performing gradual control so that there is no deviation between the actual pressure increase rate in blood pressure measurement cuff 120 and the target pressure increase rate, changes in the actual pressure increase rate in blood pressure measurement cuff 120 are suppressed as much as possible. At the same time, the actual boost speed can be converged to the target boost speed. As a result, while the actual pressure in the blood pressure measurement cuff 120 is raised within the blood pressure measurement range, the correct pulse wave signal superimposed on the sensor detection signal is acquired to accurately measure the blood pressure of the subject. can do.

Based on the pressure signal and the pulse wave signal output from the filter unit 108, the control unit 102 controls the subject's blood pressure while the actual pressure in the blood pressure measurement cuff 120 is increased within the blood pressure measurement range. to measure. Finally, the control unit 102 determines whether or not the subject's blood pressure measurement process has ended (step S260).

If the result of determination is that the blood pressure measurement process of the subject has not ended (step S260, NO), the process returns to before step S240. On the other hand, when the subject's blood pressure measurement process has ended (step S260, YES), blood pressure measurement device 100 ends the process in FIG.

In the control operation of the blood pressure measurement device 100 shown in FIG. 3, an example was described in which three patterns are used to control the boosting operation of the boosting unit 104 in accordance with the calculated initial boosting rate. , four or more patterns. In short, when the actual pressure in the blood pressure measurement cuff 120 enters the blood pressure measurement range, the calculated initial pressure increase rate is set so that the actual pressure increase rate in the blood pressure measurement cuff 120 converges to the target pressure increase rate. The boosting operation of the boosting unit 104 may be controlled accordingly.

Further, before the actual pressure in blood pressure measurement cuff 120 reaches a predetermined pressure, the pressure in blood pressure measurement cuff 120 is not increased by a predetermined amount of operation, but as in the processing of step S240. Alternatively, the pressure increasing operation of the pressure increasing unit 104 may be controlled according to the deviation between the actual pressure increasing speed in the blood pressure measurement cuff 120 and the target pressure increasing speed.

FIG. 4 shows time-series changes in the pressure in blood pressure measurement cuff 120, which is increased when the actual pressure in blood pressure measurement cuff 120 is low when the control operation of blood pressure measurement device 100 shown in FIG. 3 is executed. It is a figure which shows. In FIG. 4, the solid line LA indicates the inside of the blood pressure measurement cuff 120 when the size of the blood pressure measurement cuff 120 wrapped around the blood pressure measurement site of the subject is smaller than usual and the blood pressure measurement cuff 120 tends to inflate more easily than usual. It shows time-series changes in pressure. Dotted line LB represents the pressure in blood pressure measurement cuff 120 when blood pressure measurement cuff 120 wrapped around the subject's blood pressure measurement site has a normal size and the blood pressure measurement cuff 120 easily inflates normally. shows the time-series change of Broken line LC is the time series of the pressure in blood pressure measurement cuff 120 when blood pressure measurement cuff 120 wrapped around the subject's blood pressure measurement site is larger than usual and blood pressure measurement cuff 120 is more difficult to inflate than usual. Show change.

The control unit 102 controls the pressure increasing unit 104 so as to start the pressure increasing operation for increasing the pressure in the blood pressure measurement cuff 120 with a predetermined operation amount. After that, when the actual pressure in the blood pressure measurement cuff 120 reaches a predetermined pressure P1 before entering the blood pressure measurement range (indicated by reference numeral 220, the range in which the pressure is equal to or higher than P2), the blood pressure measurement An initial pressure increase rate in the cuff 120 is calculated.

After that, when the initial pressure increase rate is equal to or higher than the first pressure increase rate (see solid line LA), control unit 102 controls blood pressure measurement cuff 120 to increase blood pressure measurement cuff 120 when the actual pressure in blood pressure measurement cuff 120 enters blood pressure measurement range 220 . The boosting operation of the boosting unit 104 is controlled with a predetermined first control amount so that the actual boosting speed in the range converges to the target boosting speed. Further, when the initial pressure rise rate is lower than the first pressure rise rate and higher than the second pressure rise rate (see dotted line LB), the control unit 102 controls the actual pressure in the blood pressure measurement cuff 120 to fall within the blood pressure measurement range 220. The pressure increasing operation of the pressure increasing section 104 is controlled by a predetermined second control amount so that the actual pressure increasing speed in the blood pressure measurement cuff 120 converges to the target pressure increasing speed when entering. Further, when the initial boosting speed is equal to or lower than the second boosting speed (see broken line LC), control unit 102 does not control the boosting operation of boosting unit 104 with a predetermined control amount.

After that, the control unit 102 controls the pressurizing operation of the pressurizing unit 104 according to the deviation between the actual pressurizing speed in the blood pressure measurement cuff 120 and the target pressurizing speed. As shown by solid line LA, dotted line LB, and broken line LC in FIG. 4, when the actual pressure in blood pressure measurement cuff 120 enters blood pressure measurement range 220, the actual pressure increase rate in blood pressure measurement cuff 120 is equal to the target pressure increase rate. almost converges to As a result, even if the size of the blood pressure measurement cuff 120 wrapped around the subject's blood pressure measurement site is particularly smaller or larger than usual, the ease of inflating the blood pressure measurement cuff 120 is different. In the initial stage after the blood pressure measurement of the subject is started, the pressure of the blood pressure measurement cuff 120 can be stably increased at the target pressure increase rate. As a result, a correct pulse wave signal can be obtained sufficiently when the actual pressure in the blood pressure measurement cuff 120 is low, and the diastolic blood pressure of the subject can be measured with high accuracy.

FIG. 5 is a time series of the pressure in blood pressure measurement cuff 120 that is increased at a stage where the actual pressure in blood pressure measurement cuff 120 is low in the conventional technology in which the control operation of blood pressure measurement device 100 shown in FIG. 3 is not executed. It is a figure which shows a change. In FIG. 5, the solid line LD indicates the inside of the blood pressure measurement cuff 120 when the size of the blood pressure measurement cuff 120 wrapped around the blood pressure measurement site of the subject is smaller than usual and the blood pressure measurement cuff 120 tends to inflate more easily than usual. It shows time-series changes in pressure. The dotted line LE indicates the pressure in the blood pressure measurement cuff 120 when the size of the blood pressure measurement cuff 120 wrapped around the blood pressure measurement site of the subject is normal and the blood pressure measurement cuff 120 easily inflates normally. shows the time-series change of Broken line LF indicates the time series of the pressure in blood pressure measurement cuff 120 when blood pressure measurement cuff 120 wrapped around the blood pressure measurement site of the subject is larger than usual, and blood pressure measurement cuff 120 is more difficult to inflate than usual. Show change.

In the example shown in FIG. 5, when the subject's blood pressure measurement process is performed, the control unit 102 controls the pressure increase of the pressure increase unit 104 according to the deviation between the actual pressure increase speed and the target pressure increase speed in the blood pressure measurement cuff 120. Feedback control is continuously performed to control the operation. As a result, when the size of the blood pressure measurement cuff 120 wound around the blood pressure measurement site of the subject is normal and the ease of inflation of the blood pressure measurement cuff 120 is normal, as indicated by the dotted line LE in FIG. , when the actual pressure within the blood pressure measurement cuff 120 enters the blood pressure measurement range 220, the actual pressure increase rate within the blood pressure measurement cuff 120 substantially converges to the target pressure increase rate. On the other hand, when the size of the blood pressure measurement cuff 120 wrapped around the blood pressure measurement site of the subject is smaller than usual and the blood pressure measurement cuff 120 is more likely to inflate than usual, as shown by the solid line LD in FIG. When the actual pressure increase rate within the blood pressure measurement cuff 120 does not converge to the target pressure increase rate when the actual pressure within the cuff 120 enters the blood pressure measurement range 220, and the pressure is P3 or more, which is greater than P2 The actual pressure increase rate within the blood pressure measurement cuff 120 has almost converged to the target pressure increase rate.

That is, compared to the case where the control operation of blood pressure measurement device 100 shown in FIG. is longer by the change in , and it is difficult to increase the pressure at the target pressure increase rate in the initial stage after the start of blood pressure measurement of the subject. This is because feedback control generally has a response delay with respect to a control signal, and outputting a control signal does not immediately change the rate of pressure increase in the blood pressure measurement cuff 120, and is superimposed on the sensor detection signal. This is because the control amount is made small in order to suppress the occurrence of fluctuations in the pulse wave signal. In particular, if the actual pressure increase rate of the blood pressure measurement cuff 120 does not converge to the target pressure increase rate when the actual pressure in the blood pressure measurement cuff 120 is low, a sufficient correct pulse wave signal cannot be obtained. A problem arises that the diastolic blood pressure of the subject cannot be measured in the first place, or that the diastolic blood pressure cannot be measured with high accuracy.

5, when the size of the blood pressure measurement cuff 120 is larger than usual and the blood pressure measurement cuff 120 is more difficult to inflate than usual, even if the feedback control is performed, the actual inside of the blood pressure measurement cuff 120 is is considerably longer than the solid line LD and the dotted line LE until the pressure reaches the blood pressure measurement range 220 . In this case, even if the actual pressure increase rate within blood pressure measurement cuff 120 converges to the target pressure increase rate when the actual pressure within blood pressure measurement cuff 120 enters blood pressure measurement range 220, the subject's blood pressure cannot be measured. The problem arises that the time becomes very long.

As described above in detail, the blood pressure measuring device 100 of the present embodiment includes the pressure increasing section 104 that performs a pressure increasing operation to increase the pressure in the blood pressure measuring cuff 120 wrapped around the subject, and the blood pressure measuring cuff. Before the actual pressure in the blood pressure measurement range 220 enters the blood pressure measurement range 220, a calculation unit (control unit 102) that calculates the pressure increase rate (initial pressure increase rate) in the blood pressure measurement cuff 120 and the actual pressure in the blood pressure measurement cuff 120 When the pressure enters the blood pressure measurement range 220, the pressure increase operation is controlled by a predetermined control amount according to the calculated initial pressure increase rate so that the actual pressure increase rate in the blood pressure measurement cuff 120 converges to the target pressure increase rate. and a control unit 102 .

According to the present embodiment configured in this manner, the pressure in blood pressure measurement cuff 120 is increased according to the initial pressure increase rate calculated before the actual pressure in blood pressure measurement cuff 120 enters blood pressure measurement range 220. The pressure increase operation is controlled by a predetermined control amount so that the actual pressure increase speed in blood pressure measurement cuff 120 converges to the target pressure increase speed when the actual pressure of enters blood pressure measurement range 220 . Therefore, compared to the case where feedback control is performed to control the pressure-increasing operation of the pressure-increasing section 104 according to the difference between the actual pressure-increasing speed and the target pressure-increasing speed in the blood-pressure measuring cuff 120, pressure-increasing pressure within the blood-pressure measuring cuff 120 can be increased more quickly. It is possible to converge the actual boosting speed closer to the target boosting speed. Therefore, in the initial stage after the start of blood pressure measurement of the subject, the pressure of the blood pressure measurement cuff 120 wrapped around the subject can be increased at the target pressure increase rate. As a result, a correct pulse wave signal of the subject can be obtained sufficiently when the actual pressure in the blood pressure measurement cuff 120 is low, and the diastolic blood pressure of the subject can be measured with high accuracy.

In the above-described embodiment, the blood pressure measuring device 100 may be used to measure the blood pressure of the subject using the pressure-lowering measurement method in addition to the pressure-boosting measurement method.

In the above embodiment, the blood pressure measuring device 100 is incorporated in a biological information monitor (specifically, a bedside monitor, a telemeter, etc.) for measuring biological information, a Holter sphygmomanometer, a blood pressure pulse wave device, or the like. may be used as

In addition, each of the above-described embodiments is merely an example of specific implementation of the present invention, and the technical scope of the present invention should not be construed to be limited by these. Thus, the invention may be embodied in various forms without departing from its spirit or essential characteristics.

REFERENCE SIGNS LIST 100 blood pressure measuring device 102 control unit 104 pressure increasing unit 104A air supply unit 104B exhaust unit 106 pressure detection unit 108 filter unit 110 storage unit 112 operation unit 114 display unit 120 blood pressure measurement cuff

Claims (5)

A blood pressure measurement device that measures the blood pressure of the subject while the pressure in the cuff wrapped around the subject is increased within a blood pressure measurement range,
a boosting unit that performs a boosting operation to boost the pressure in the cuff;
a calculation unit that calculates a pressure increase rate in the cuff before the pressure in the cuff enters the blood pressure measurement range;
The pressure increase operation is performed by a predetermined control amount according to the calculated pressure increase rate so that the pressure increase rate in the cuff converges to the target pressure increase rate when the actual pressure in the cuff enters the blood pressure measurement range. a control unit that controls
Blood pressure measuring device. The predetermined control amount is a control amount according to a comparison between the calculated pressure increase speed and a plurality of predetermined pressure increase speeds.
The blood pressure measuring device according to claim 1. After controlling the boosting operation with the predetermined control amount, the control unit controls the boosting operation according to the deviation between the actual boosting speed in the cuff and the target boosting speed.
The blood pressure measuring device according to claim 1 or 2. The boosting unit is
an air supply unit that supplies air to the cuff;
an exhaust unit that exhausts air to the cuff;
and changing the combination of the air supply control amount and the exhaust control amount based on the result of the comparison;
The blood pressure measuring device according to claim 2. A control method in a blood pressure measuring device for measuring the blood pressure of a subject while the pressure in a cuff wrapped around the subject is increased within a blood pressure measurement range,
before the pressure in the cuff enters the blood pressure measurement range, calculating the pressure increase rate in the cuff;
The pressure increase operation is controlled by a predetermined control amount according to the calculated pressure increase rate so that the pressure increase rate in the cuff converges to a target pressure increase rate when the pressure in the cuff enters the blood pressure measurement range. ,
control method.

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