JPH0657200B2 - Cuff booster for blood pressure measurement - Google Patents

Description

TECHNICAL FIELD The present invention relates to a device for pressurizing a cuff that compresses a part of a living body when measuring blood pressure.

2. Description of the Related Art When measuring blood pressure, air is pressure-fed to a cuff wrapped around a part of the living body such as the upper arm to pressurize this, thereby compressing a part of the living body while gradually releasing air from the inside of the cuff. By discharging, the compression pressure is decreased at a predetermined speed, and the change of the pulse wave synchronized with the heartbeat that changes with the change of the compression pressure in the decrease process, for example, Korotkoff sound (so-called K sound).
Conventionally, an automatic blood pressure measuring device has been proposed that determines the blood pressure value by detecting the occurrence and disappearance of the blood pressure, and the change in the magnitude of pressure vibration of the cuff that occurs in synchronization with the heartbeat. Then, in such an automatic blood pressure measuring device, when air is supplied to the cuff to increase the pressure, it is common to directly send air to the cuff from an electric pump or the like, in order to shorten the blood pressure measurement. It is desirable to shorten the pressure rising time of the cuff as much as possible, but the pressure rising speed of the cuff is limited by the discharge capacity of the electric pump.

Problems to be Solved by the Invention On the other hand, as described in, for example, Japanese Utility Model Publication No. 35-33263, a cuff booster of a type in which air is pumped from an electric pump and a pressure vessel during blood pressure measurement to boost the cuff. A device has been proposed. According to such a device, compared with the case where the pressure of the cuff is boosted only by the electric pump, the compressed air accumulated in the pressure vessel is also sent to the cuff in addition to the discharge capacity of the electric pump, so that the blood pressure measurement is performed. In this case, there is an advantage that the pressure rising speed of the cuff is improved.

However, in the conventional device as described above, there is a case where the systolic blood pressure value of the measurement subject is high, or the capacity thereof changes depending on the type of the cuff and the winding state of the cuff. In this case, if the boost pressure of the cuff does not reach the target pressure even when the delivery of the compressed air accumulated in the pressure vessel is completed, that is, the pressure in the pressure vessel becomes equal to the pressure in the cuff. There is. On the other hand, when the electric pump is further driven to make the pressure in the cuff reach the target pressure, the electric pump raises not only the pressure in the cuff but also the pressure vessel, and the volume in the pressure vessel is increased. However, there is a drawback in that it requires an extra boosting time.

The present invention has been made in the background of the above circumstances,
It is an object of the present invention to provide a cuff pressurizing device capable of promptly increasing the pressure of the cuff even when the cuff does not reach the target pressure due to the supply of the compressed air accumulated in the pressure vessel.

Means for Solving the Problems In order to achieve such an object, the gist of the present invention is to provide a pressure vessel for accumulating pressure, an electric pump for feeding compressed air to the pressure vessel, and a living body. A cuff for compressing a part of the cuff and a first valve device provided between the pressure container and the electric pump, and the first valve device is closed outside the pressure increasing period of the cuff to drive the electric pump. In this way, the pressure is stored in the pressure container, while the first valve device is opened for blood pressure measurement, so that the compressed air stored in the pressure container is released to the cuff to quickly pressurize the cuff. A pressure increasing device for a cuff,
(a) a control device that further drives the electric pump when the pressure increase of the cuff is insufficient during the pressure increasing period of the cuff; and (b) the pressure container provided between the pressure container and the electric pump. In a state where the pressure is stored in the inside and a state in which the compressed air stored in the pressure vessel is released, the state in which the pressure vessel and the electric pump are opened while the electric pump is further driven by the control device In the second aspect, the second valve device for shutting off the electric pump and the pressure vessel is included.

By doing so, in the case where the pressure in the cuff due to the compressed air accumulated in the pressure container does not reach the target pressure sufficiently and the pressure increase pressure of the cuff is insufficient during the pressure increase period of the cuff. Since the electric pump is further driven by the control device, the cuff is further pressurized. Also,
In a state where the electric pump is further driven, the electric valve and the pressure vessel are shut off by the second valve device, so that the electric pump only needs to boost the pressure in the cuff,
Since it is not necessary to further increase the pressure in the pressure container, the pressure in the cuff can quickly reach the target pressure.

Embodiment Next, one embodiment of an automatic blood pressure measuring device provided with a booster according to the present invention will be described in detail with reference to the drawings.

In FIG. 1, reference numeral 10 denotes a rubber bag-like cuff that is wound around an arm or the like of a human body for blood pressure measurement.
A tank 12 as a pressure container for supplying air into the cuff 10 via a pipe 14 is connected to the. Two electromagnetic opening / closing valves MV1 and MV2 that constitute a switching valve device are arranged in series in the pipe 14, and these electromagnetic opening / closing valves MV are arranged.
An electric pump 16 for sending air under pressure is connected between 1 and MV2. The electric pump 16 is driven prior to the blood pressure measurement, and passes through the electromagnetic opening / closing valve MV1 and then the tank 12 described above.
The compressed air filled in the tank 12 in this manner is responsive to the blood pressure measurement operation, that is, the operation of starting the pressurization of the cuff 10, and the electromagnetic opening / closing valve MV.
1 and MV2 to be fed into the cuff 10. The electromagnetic opening / closing valve MV2 functions as the first valve device of this embodiment. Further, the electromagnetic opening / closing valve MV1 is provided between the tank 12 and the electric pump 16, and is in an open state in a state where pressure is accumulated in the tank 12 and a state in which compressed air accumulated in the tank 12 is released. On the other hand, in the state where the electric pump 16 is further driven by the electronic control unit when the pressure is insufficiently boosted only by the compressed air accumulated in the tank 12, the electric pump 16 and the tank 12 are closed. belongs to. Therefore, the solenoid on-off valve MV1 functions as a second valve device in this embodiment.

A pressure sensor 18 that detects the pressure of the compressed air (tank pressure P _T ) sent from the electric pump 16 into the tank 12 is connected between the tank 12 and the electromagnetic opening / closing valve MV1. The pressure sensor 18 has an A / D converter, converts a signal representing the tank pressure P _T into a digitally coded pressure signal SC, and then supplies the pressure signal SC to the I / O port 20. In addition, between the electric pump 16 and the electromagnetic opening / closing valves MV1 and MV2, the electromagnetic opening / closing valve MV is separated from the electric pump 16.
Check valve 22 whose forward direction is toward 1 and MV2
Is provided.

In the portion of the pipe 14 between the cuff 10 and the electromagnetic on-off valve MV2, the pressure of the compressed air fed into the cuff 10 (cuff pressure P
The pressure sensor 24 that detects c) and outputs a pressure signal SP that represents the cuff pressure Pc is connected to an exhaust control valve device 26 that exhausts the compressed air fed into the cuff 10. The exhaust control valve device 26 is in a closed state in which the air in the cuff 10 is blocked, a slow exhaust state in which the air in the cuff 10 is gradually exhausted for blood pressure measurement, and the air in the cuff 10 is rapidly exhausted. It is possible to switch to at least three states such as a rapid exhausting state in which the exhaust gas is discharged in stages or continuously. That is, the exhaust control valve device 26 is composed of, for example, a rapid exhaust on-off valve, a slow exhaust exhaust throttle valve, and an on-off valve.

The pressure signal SP output from the pressure sensor 24 is supplied to the pulse wave sensor 28 and the pulse wave remover 30, respectively.
The pulse wave sensor 28 includes a bandpass filter and an A / D converter, extracts only the pulse wave component (for example, a pressure oscillation component of about 10 to 50 Hz) from the pressure signal SP, digitally encodes the pulse wave component. After being converted into the wave signal SM, it is supplied to the I / O port 20. The pulse wave remover 30 includes a low-pass filter and an A / D converter,
After removing the vibration component generated in synchronization with the pulse of the human body from the pressure signal SP, the signal representing the static pressure in the cuff 10 is converted into a digitally encoded pressure signal SK, and I /
Supply to O port 20. Further, the K sound detection circuit 31
The signal from the microphone 29 attached to the cuff 10 for detecting the Korotkoff sound is discriminated by, for example, a predetermined bandpass filter, and then the Korotkoff sound is detected based on whether the signal value exceeds a predetermined judgment criterion. , The signal KK indicating the Korotkoff sound is supplied to the I / O port 20. A command signal SS is supplied to the I / O port 20 from the push button PB.

The I / O port 20 is connected to a CPU 32, R of a microcomputer as an electronic control device via a data bus line.
It is connected to the OM 34 and the RAM 36. CPU3
2 is a ROM 34 while using the temporary storage function of the RAM 36
The input signal is processed in accordance with a program stored in advance in the electric pump 16, the drive signal SA is supplied to the electric pump 16, and the drive signal SL1 or SL2 is supplied to the exhaust control valve device 26.
To the electromagnetic open / close valves MV1 and MV2.
V1 and SV2 are supplied respectively. Drive signal SL1
Alternatively, SL2 sets the exhaust control valve device 26 to the slow exhaust state or the rapid exhaust state, respectively, and the drive signals SV1 and SV2 open the electromagnetic opening / closing valves MV1 and MV2, respectively. Also, blood pressure indicator 3
A display signal SB is supplied to 8 to display the maximum blood pressure value and the minimum blood pressure value in numbers.

The operation of this embodiment will be described below with reference to the flowchart of FIG. 2 and the time chart of FIG. The graph of the tank pressure P _T and the cuff pressure Pc in FIG. 3 is represented by assuming that the atmospheric pressure is 0 mmHg.

First, when a power switch (not shown) is turned on, step S1 is executed and the tank pressure P _T (mm
Hg) value is read and step S2 is executed to set the tank pressure P _T to a predetermined constant pressure Pa (mm
Hg) or more is determined. When the tank pressure P _T is equal to or higher than the constant pressure Pa, step S4 is executed,
Immediately after the power switch is turned on, the tank pressure P is not sufficiently filled with compressed air.
_{Since T} is lower than the constant pressure Pa, step S3 is executed. Here, the constant pressure Pa is a value that is sufficiently higher than the systolic blood pressure value of the measurement subject, and the compressed air in the tank 12 enters the cuff 10 through the electromagnetic opening / closing valve MV1, the electromagnetic opening / closing valve MV2, and the pipe 14. Even if the pressure difference between the air in the tank 12 and the air in the cuff 10 disappears as a result of the supply, the pressure in the tank 12 and the cuff will be higher than the systolic blood pressure value of the measurement subject. 10, and is determined in consideration of the capacity of the pipe 14.

In step S3, the electromagnetic on-off valve MV1 is opened according to the drive signal SV1, the electric pump 16 and the tank 12 are made to communicate with each other, and the electric pump 16 is operated according to the drive signal SA. At this time, since the electromagnetic opening / closing valve MV2 remains closed, compressed air is supplied from the electric pump 16 into the tank 12 via the check valve 22 and the electromagnetic opening / closing valve MV1, and the tank pressure P _T rises. Be started. The point t _{1 in} FIG. 3 indicates this point.

Thereafter, when the tank pressure P _T reaches the constant pressure Pa while the above-described steps S1, S2 and S3 are repeatedly executed, the determination in step S2 is affirmed, and thus the next step S4 is executed. In step S4, the output of the drive signals SV1 and SA is stopped, and the electromagnetic opening / closing valve MV1
Is closed and the electric pump 16 is stopped. That is, the electric pump 16 accumulates compressed air in the tank 12 by its operation. Note that t _{2 in} FIG. 3 indicates the time when the compressed air is accumulated in the tank 12.

Next, as described above, in the state where the tank pressure P _T is equal to or higher than the constant pressure Pa, step S5 is executed and whether or not the start push button PB for measuring the blood pressure is operated, in other words, the command signal SS. Is supplied to the I / O port 20. If the command signal SS is not supplied, the execution of step S1 and the subsequent steps is repeated. When a long time elapses before the start push button PB is operated and the tank pressure P _T becomes lower than the constant pressure Pa, the step S1 and the subsequent steps are repeatedly executed, so that the tank pressure P _T is always the constant pressure. It is maintained near Pa. In addition,
In order to provide a hysteresis in the determination in step S2, the pressure Pa has a predetermined range width (for example, 10 mmHg).
However, even if the compressed air in the tank 12 slightly leaks, the electric pump 16 may be prevented from being frequently operated.

In the above state, after the cuff 10 is wound around the upper arm of the human body or the like, the start push button PB is pressed to give the command signal SS.
Is supplied to the I / O port 20, steps S6 and S7 are executed, the pressure signal SK supplied from the pressure sensor 24, that is, the cuff pressure Pc (mmHg) is read, and the electromagnetic opening / closing valves MV1 and MV2 are turned on. Drive signal S
Both are opened according to V1 and SV2. Therefore, the compressed air in the tank 12 is rapidly fed into the cuff 10 via the electromagnetic opening / closing valves MV1 and MV2 based on the pressure difference between the tank pressure P _T and the cuff pressure Pc, and the tank pressure P _T Simultaneously with the fall, the cuff pressure Pc is rapidly increased. In FIG. 3, t ₃ indicates the time when the boosting is started.

Next, step S8 is executed, and the cuff pressure Pc read in step S6 is the predetermined target pressure P.
It is determined whether or not it is o (mmHg) or more. While the cuff pressure Pc is lower than the target pressure Po, the steps S6, S7 and S are performed.
8 is repeated, but the cuff pressure Pc is equal to the target pressure Po.
When step S9 is reached, step S9 is executed, the output of the drive signals SV1 and SV2 is stopped, and the electromagnetic opening / closing valves MV1 and MV
V2 is closed. Here, the target pressure Po is higher than the systolic blood pressure value of a general subject, for example, 180 mm.
The tank pressure P _T is lowered to a pressure Pb (mmHg) equal to or higher than the target pressure Po at this time. That is, as shown by the solid line in FIG. 4, the cuff pressure Pc rapidly rises after the electromagnetic on-off valves MV1 and MV2 are opened and the cuff 10 is filled with air, but thereafter, the cuff pressure Pc and the tank pressure Pc. _As the pressure difference from _T decreases, the rising speed of the cuff pressure Pc sharply slows down. Therefore, the cuff pressure Pc reaches the target pressure Po before the rising speed slows down. Is defined as such. The time t _{4 in} FIG. 3 shows this state, and the time difference between t ₃ and t ₄ is, for example, about 1 second.

In this way, the cuff pressure Pc is the target pressure Po (180 mmHg)
As shown in Fig. 4, it takes about 1 second to reach to, compared to about 5 seconds in the conventional case where air is sent directly from the electric pump to the cuff, which is indicated by the alternate long and short dash line. hand,
The pressurization time of the cuff 10 is greatly shortened. The check valve 22 need not be provided when the amount of leakage of the electric pump 16 is extremely small.

By the way, when the systolic blood pressure value is higher than the target pressure Po due to the individual difference of the person to be measured, and the cuff 10 used
Cuff 10 depending on the type of cuff
Therefore, the cuff pressure Pc may not reach the target pressure Po only by discharging the compressed air accumulated in the tank 12. For this purpose, the following step S10
S through S15 are provided to further pressure-feed air from the electric pump 16 to the cuff 10.

That is, in first step S10, the pressure P ₁ to a slight predetermined pressure ΔP to the target pressure Po (about 5～10MmHg) was added is calculated, whether K tones in a subsequent step S11 is detected is determined It Here, when the subject's systolic blood pressure value is lower than the cuff pressure Pc and the blood flow in the artery is completely cut off, the K sound does not occur.
The detection of the K sound means that the cuff pressure Pc has not yet reached the systolic blood pressure value of the measurement subject.

When the K sound is not detected, the blood pressure measurement routine of step S16 is executed. In this blood pressure measurement routine, first, the exhaust control valve device 26 is held in the gradual exhaust state according to the drive signal SL1 to slowly decrease the cuff pressure Pc, and in this state, the magnitude of the pulse wave represented by the pulse wave signal SM is increased. The cuff pressure Pc at the time when the increase rate and the decrease rate of the peak value of the pulse wave are maximum is determined from the change in the height as the systolic blood pressure value and the diastolic blood pressure value, respectively. After that, the exhaust control valve device 26 is kept in the rapid exhaust state in accordance with the drive signal SL2, the air in the cuff 10 is rapidly exhausted, the part of the human body which has been compressed until then is released, and the above-mentioned determination is made. The maximum blood pressure value and the minimum blood pressure value are displayed numerically on the blood pressure display 38. The graph of the cuff pressure Pc after the time t _{4 in} FIG. 3 shows the pressure change in the slow exhaust state during the blood pressure measurement. When the exhaust of the air in the cuff 10 is completed, the output of the drive signal SL2 is stopped and the exhaust control valve device 26 is closed. Then, after that, step S1 and subsequent steps are executed again, the compressed air is filled in the tank 12 to make the tank pressure P _T equal to or higher than the constant pressure Pa, and steps S1 to S5 are performed until the push button PB is pressed next time. Is repeated.

However, if it is determined in step S11 that the K sound is detected, that is, if the cuff pressure Pc is lower than the systolic blood pressure value of the measurement subject, in the subsequent step S12, the electromagnetic opening / closing valve MV2 follows the drive signal SV2. The electric pump 16 and the cuff 10 are opened to communicate with each other, and the electric pump 16 is operated according to the drive signal SA. Therefore, the air is further pumped from the electric pump 16 to the cuff 10, and the cuff pressure Pc is further increased.
At this time, since the electromagnetic on-off valve MV1 is still closed in step S9, the tank 12 cannot be further pressurized.

Next, step S13 is executed to judge whether the cuff pressure Pc is equal to or higher than the pressure P ₁ calculated in step S10. When the cuff pressure Pc is lower than the pressure P _1, the execution of steps S12 and S13 is repeated, but when the cuff pressure Pc reaches the pressure P ₁ , the solenoid opening / closing valve is stopped in step S14 to stop the pressure increase of the cuff pressure Pc. The MV 2 is closed and the operation of the electric pump 16 is stopped. Subsequently, step S15 is executed so that the pressure P ₁ is smaller than the pressure P ₁ up to then by the pressure ΔP.
After the pressure is changed to a pressure higher by the same pressure as above, the step S11 is executed again to determine whether or not the K sound is detected, in other words, the cuff pressure Pc increased by the pressure ΔP is the maximum blood pressure of the subject. It is determined whether it is lower than the value. When the cuff pressure Pc is lower than the systolic blood pressure value of the measurement subject, the execution of steps S12 to S15 is repeated to obtain the cuff pressure Pc.
Is sequentially increased by pressure ΔP, and when the cuff pressure Pc becomes higher than the systolic blood pressure value of the measurement subject and K sound is no longer detected, the blood pressure measurement routine of step S16 is executed.

As described above, according to the automatic blood pressure measurement device of the present embodiment,
Compressed air having a constant pressure Pa is accumulated in the tank 12 prior to the pressing operation of the start push button PB for blood pressure measurement, that is, the operation of starting the pressurization of the cuff 10, and the tank is responded to the subsequent operation of starting the pressurization of the cuff 10. Since the compressed air in 12 is rapidly fed into the cuff 10, the cuff pressure Pc is increased all at once in a short time. Therefore, according to the present embodiment, the pressurization time of the cuff is greatly shortened and the time required for blood pressure measurement is improved. According to experiments conducted by the present inventors, the time required to pressurize the cuff was improved to about 1/4 to 1/5, and the time required to measure the blood pressure was improved to about 2/3 to 3/4.

Moreover, according to the present embodiment, the inner volume of the cuff 10 is higher than the target pressure Po of the cuff 10 according to the individual difference of the person to be measured, or the inner volume of the cuff 10 varies depending on the type of the cuff 10 used and the winding manner of the cuff 10. Changes, tank 12
Even if the pressure rise is insufficient with only the filling amount inside, the cuff 10 is further increased by the electric pump 16 driven by the electronic control device, and the cuff pressure Pc is automatically increased to the systolic blood pressure value or higher. Therefore, the blood pressure can be quickly measured regardless of the person to be measured and the variation in the volume inside the cuff 10. In particular, in this embodiment, as described above, the tank 12
When the pressure in the cuff 10 is insufficiently increased only by the compressed air in the cuff 10 and the air is further pumped from the electric pump 16, the electromagnetic on-off valve MV1 is in the closed state. There is no need to further increase the pressure inside the cuff 10, and only the pressure inside the cuff 10 needs to be increased.
It is possible to quickly reach above the systolic blood pressure of the subject.

Although one embodiment of the present invention has been described in detail with reference to the drawings, the present invention can be implemented in other modes.

For example, in the above-described embodiment, the operation of the electric pump 16 and the opening / closing of the electromagnetic opening / closing valves MV1 and MV2 are performed by the tank pressure P _T and the cuff pressure Pc detected by the pressure sensors 18 and 24.
However, the pump operating time for obtaining a sufficient tank pressure is determined in advance by considering the discharge capacity of the electric pump 16 and the capacity of the tank 12 and the cuff 10 while turning on the power. It is also possible to operate the pump 16 together with the electromagnetic opening / closing valves MV1 and MV2 for the above operation time at the time of starting the pressurization of the cuff 10 (for example, in step S7), thereby filling the tank 12 with air of a predetermined pressure. It is possible. In this case,
It is necessary to close only the electromagnetic opening / closing valve MV2 after it is determined to be YES in step S8 (for example, in step S9). With this configuration, it is not necessary to provide the pressure sensor 18 and steps S1 to S4.

Further, in the above-described embodiment, when the cuff pressure Pc reaches the target pressure Po, the tank pressure P _T is still maintained at the pressure Pb higher than the target pressure Po, while the solenoid opening / closing valves MV1 and MV2 are closed. Although the communication between the cuff 10 and the tank 12 is cut off, a constant pressure Pa is maintained by supplying air from the tank 12 to the cuff 10 by opening the electromagnetic opening / closing valves MV1 and MV2. If the pressure difference between the pressure P _T and the cuff pressure Pc is eliminated, and the pressure is determined to be the target pressure Po, the electromagnetic opening / closing valve M
No control step is required to close V1 and MV2 to disconnect communication between cuff 10 and tank 12.

Further, in the above-described embodiment, the solenoid valve M has two switching valve devices.
Other switching valve devices such as an electromagnetic switching valve, which is composed of V1 and MV2, but is capable of switching between two states: a state in which the tank 12 communicates with the cuff 10 and a state in which the tank 12 communicates with the electric pump 16. It is also possible to adopt.

It should be noted that the above description is merely an example of the present invention, and it goes without saying that the present invention can be implemented in various modified and improved modes without departing from the spirit thereof.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating the configuration of an automatic blood pressure measuring device including a cuff pressure increasing device according to an embodiment of the present invention. FIG. 2 is a flow chart for explaining the operation of the apparatus shown in FIG. FIG. 3 is a time chart for explaining the operation accompanying the execution of the flowchart of FIG. FIG. 4 is a graph showing changes in the cuff pressure when the cuff pressure is increased, comparing the case of the apparatus of FIG. 1 and the case of the conventional apparatus. FIG. 5 is a part of a flowchart explaining the operation of another embodiment of the present invention. 10: Cuff, 12: Tank (pressure container) 16: Electric pump 32: CPU electronic control device (control device) 33: ROM electronic control device (control device) 36: RAM electronic control device (control device) MV1: Electromagnetic on-off valve (Second valve device) MV2: Electromagnetic on-off valve (first valve device)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-50-119486 (JP, A) Jikkō 35-33263 (JP, Y1)

Claims (1)

[Claims] 1. A pressure vessel for accumulating pressure, an electric pump for feeding compressed air to the pressure vessel, a cuff for compressing a part of a living body, and the pressure vessel and the electric pump. A first valve device provided, and while the first valve device is closed outside the pressure increasing period of the cuff to drive the electric pump to accumulate pressure in the pressure container, the first valve device is used for blood pressure measurement. A pressure increasing device for a blood pressure measuring cuff of a type in which compressed air accumulated in the pressure vessel is released to the cuff to open the cuff quickly by opening, and the pressure of the cuff is increased during a pressure increasing period of the cuff. A control device that further drives the electric pump when the pressure is insufficient, a state where the pressure container is provided with pressure between the control device and the electric pump, and a state in which the pressure inside the pressure container is accumulated and a compression accumulated in the pressure container. In the state where air is discharged, the pressure vessel and the electric pump are opened, while in the state where the electric pump is further driven by the control device, the electric pump and the pressure vessel are shut off from each other. And a second valve device.