JPH0580208B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a non-invasive continuous blood pressure measuring device that continuously measures the blood pressure value of a living body.

BACKGROUND ART Blood pressure measuring methods are generally classified into invasive methods and non-invasive methods. The former involves inserting a catheter into the body's blood vessels and directly measuring the body's blood pressure with a pressure gauge connected to the catheter, while the latter is equipped with a compression means to compress a part of the body. This method indirectly measures the blood pressure value of a living body.

By the way, when comparing these invasive blood pressure measurement methods and non-invasive blood pressure measurement methods, the non-invasive method has advantages such as simpler device configuration and handling, and less impact on the living body. The blood pressure measurement method is more advantageous, and therefore, it is desirable to use a non-invasive blood pressure measuring device to measure the blood pressure value of a living body.

Problems to be Solved by the Invention However, in conventional non-invasive blood pressure measuring devices, the compression pressure of the compression means against the living body is varied at a constant rate of change, and the pressure is synchronized with the heartbeat that occurs during the variation process of the compression pressure. Blood pressure values were determined by detecting blood flow sounds and pulse waves, etc., and based on changes in these detected blood flow sounds and pulse waves, so it took a relatively long time to measure blood pressure values. However, for this reason, the actual situation has been that its use has been limited to those in which blood pressure values are measured once or repeatedly at relatively long intervals. In other words, one of the ways in which a blood pressure measuring device is used to examine the reaction of a living body based on changes in blood pressure values when diagnosing autonomic nervous disorders, etc. is to measure the systolic blood pressure value of the living body as continuously as possible. However, as mentioned above, conventional non-invasive blood pressure measuring devices cannot be used for this type of system because of the long period in which they can repeatedly measure blood pressure values. Therefore, it was necessary to use an invasive blood pressure measuring device as described above.

The present invention has been made against the background of the above circumstances, and its object is to provide a non-invasive continuous blood pressure measuring device that can continuously measure systolic blood pressure values.

First Means for Solving the Problem The gist of the present invention for achieving the above object is to continuously measure the blood pressure value of a living body, as shown in the diagram corresponding to the claims of the first invention in FIG. It is a non-invasive continuous blood pressure measuring device that measures blood pressure by (a) a compression means having a cuff for compressing a part of the living body, and (b) pressure generated from within the living body by the compression by the compression means. (c) a microphone that detects blood flow sounds;
(d) following the determination of the systolic blood pressure by the systolic blood pressure value determining means; , a blood pressure lowering means for lowering the compression pressure of the compression means by a predetermined pressure than the systolic blood pressure value, and (e) the magnitude of the blood flow sound at the time when the compression pressure is lowered by the predetermined pressure by the pressure lowering means. (f) control means for continuously controlling the compression pressure so that the magnitude of the blood flow sound matches the reference value; and (g) control thereof. continuous blood pressure value determining means for continuously determining the systolic blood pressure value of the living body based on compression pressure continuously controlled by the means;
(h) A display means for continuously displaying the systolic blood pressure value determined by the continuous blood pressure value determination means.

In this way, after the systolic blood pressure value is determined by the systolic blood pressure value determining means while changing the compression pressure applied to the part of the living body by the compression means, the blood pressure lowering means compresses the part of the living body. The pressure is lowered by a predetermined pressure from the systolic blood pressure value, and the reference value determining means determines the magnitude of the blood flow sound at the time when the pressure is lowered by the predetermined pressure as the reference value. The control means continuously controls the compression pressure of the compression means so that the magnitude of the blood flow sound matches the reference value, and the continuous blood pressure value determination means determines the systolic blood pressure based on the compression pressure. is continuously determined, and the systolic blood pressure value is continuously displayed by the display means.

Effects of the First Invention As described above, in the continuous blood pressure value determination device of the present invention, the systolic blood pressure value is calculated from the compression pressure of the compression means that is controlled to follow the fluctuation of the systolic blood pressure value based on the magnitude of the blood flow sound. Since the blood pressure is determined, the systolic blood pressure value can be measured continuously in a non-invasive manner.

Second Means for Solving the Problems The gist of another aspect of the present invention for solving the above problems is as shown in the diagram corresponding to the claims of the second invention in FIG. A non-invasive continuous blood pressure measuring device that continuously measures blood pressure values, the device comprising: (a) a compression means having a cuff for compressing a part of a living body; and (b) the cuff synchronized with the heartbeat of the living body. (c) a systolic blood pressure value determining means for determining a systolic blood pressure value of the living body while changing the compression pressure of the compression means against the part of the living body; (d) a blood pressure reducing means for lowering the compression pressure of the compression means by a predetermined pressure from the systolic blood pressure value following the determination of the systolic blood pressure value by the blood pressure value determination means; (f) a reference value determining means for determining the magnitude of the pulse wave at the time when the pressure is lowered by the predetermined pressure as a reference value; and (f) determining the compression so that the magnitude of the pulse wave matches the reference value. (g) continuous blood pressure value determination means that continuously determines the systolic blood pressure value of the living body based on the compression pressure continuously controlled by the control means; (h) ) Display means for continuously displaying the systolic blood pressure value determined by the continuous blood pressure value determination means.

In this way, after the systolic blood pressure value is determined by the systolic blood pressure value determining means while changing the compression pressure applied to the part of the living body by the compression means, the blood pressure lowering means compresses the part of the living body. The pressure is lowered by a predetermined pressure from the systolic blood pressure value, and the reference value determination means determines the magnitude of the pulse wave at the time when the pressure has been lowered by the predetermined pressure as the reference value. The control means continuously controls the compression pressure of the compression means so that the magnitude of the pulse wave matches the reference value, and the continuous blood pressure value determining means determines the systolic blood pressure value based on the compression pressure. The systolic blood pressure value is continuously determined and displayed continuously by the display means.

Effect of the Second Invention As described above, in the continuous blood pressure measuring device according to the second aspect, the systolic blood pressure value is determined from the compression pressure of the compression means, which is controlled to follow the fluctuation of the systolic blood pressure value based on the magnitude of the pulse wave. Since the blood pressure is determined, the systolic blood pressure value can be measured continuously in a non-invasive manner.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail based on the drawings.

In FIG. 3, reference numeral 10 denotes a cuff attached to a part of a living body, for example, the upper arm, to compress the upper arm, and is supplied with air from an electric pump 14 via an electromagnetic air supply valve 12. Air damper 16
It is connected to the atmosphere and communicated with the atmosphere via an electromagnetic exhaust valve 18, and the compression pressure on the living body is adjusted by supplying air from the electromagnetic air supply valve 12 and exhausting air from the electromagnetic exhaust valve 18. It is becoming possible to do so. That is, in this embodiment, the cuff 10, the electromagnetic air supply valve 12, the electric pump 14, the air damper 16, and the electromagnetic exhaust valve 18 constitute the compression means. Note that a relief valve 19 is connected to the air damper 16, and the damper 16
The internal pressure is kept from rising above a certain level, for example 300mmHg.

Further, a pressure sensor 20 and a microphone 22 are connected to the cuff 10.
0 detects the pressure inside the cuff 10, and the microphone 22 detects Korotkoff sounds (hereinafter simply referred to as K sounds), which are blood flow sounds. The pressure inside the cuff 10 detected by the pressure sensor 20 is supplied to the low-pass filter 26 as a pressure signal SP, and the K sound detected by the microphone 22 is supplied to the first band-pass filter 28 as a K sound signal SK. . The low-pass filter 26 detects static pressure from which vibration components have been removed from the pressure signal SP, and supplies a pressure signal SP' representing this static pressure to the A/D converter 30. Further, the first band pass filter 28 is K
A signal of about 30 to 80 Hz is extracted from the sound signal SK and supplied to the A/D converter 30. and,
The A/D converter 30 time-divisionally A/D converts the signals supplied from each of the filters according to the command signal from the I/O port 32, and sends the digitized signals to the I/O port 32. supply

On the other hand, the I/O port 32 has a start push button 3.
8 is connected so that a start signal ST is supplied based on the pressing operation, and a timer 40 is connected so that a time-up time can be set by a setting device 39. Time-up signal SU from timer 40
is now being supplied.

The I/O port 32 is connected via the data bus line.
It is connected to the CPU 42, RAM 44, and ROM 46, and receives the pressure signal SP' from the A/D converter 30, the K sound signal SK, and the start signal from the start push button 38 according to instructions from the CPU 42.
ST and the time-up signal SU from the timer 40 are supplied to the data bus line. CPU42
executes signal processing using the temporary storage function of the RAM 44 according to a program stored in the ROM 46 in advance, and sends the pump drive signal SA, air supply control signal SC, and exhaust control signal SE via the I/O port 32.
and timer operation signal SS to the pump drive circuit 48, intake valve drive circuit 50, exhaust valve drive circuit 52, and timer 40, respectively, and
The systolic blood pressure value of the living body obtained as a result of signal processing is supplied to the display device 54 as a display signal DD.

The pump drive circuit 48 supplies drive power to the electric pump 14 while the pump drive signal SA is being supplied, and causes air to be pumped to the air damper 16. While the air supply control signal SC is being supplied, the air supply valve drive circuit 50 supplies driving power to the electromagnetic air supply valve 12 to open the electromagnetic air supply valve 12 and transfer the air in the air damper 16 to the cuff 10. to be pumped to. Further, the exhaust valve drive circuit 52 includes a D/A converter (not shown), and supplies driving power to the electromagnetic exhaust valve 18 according to the contents of the exhaust control signal SE to control the electromagnetic exhaust valve 18. The opening degree is adjusted according to the cuff 10, and the amount of exhaust from the cuff 10 is controlled. Furthermore, the timer 40 starts operating from the time when the timer activation signal SS is input, and outputs the time-up signal SU after the time set by the setting device 39 has elapsed from the time when the timer activation signal SS was input.

With such a non-invasive continuous blood pressure measuring device, the systolic blood pressure value of a living body can be measured continuously, almost every beat of the heartbeat, according to the flowchart shown in Figure 4. ing. Hereinafter, the operation of the present blood pressure measuring device will be explained according to this flowchart.

When the power is turned on, first, in step S1, the time-up time _Tp of the timer 40 is set by the setting device 39, and a period of continuous measurement of the systolic blood pressure value is set. After setting this continuous measurement period, step S2 is executed.

In this step S2, it is determined whether or not the start push button 38 has been pressed. When the start signal ST is input and it is determined that the start push button 38 has been pressed, step S3 is subsequently executed, the exhaust control signal SE is set to close the electromagnetic exhaust valve 18, and the air supply is The control signal SC is supplied to the air supply valve drive circuit 50 to open the electromagnetic air supply valve 12, and at the same time the pump drive circuit 4
8 is supplied with a pump drive signal SA to drive the electric pump 14, and the air damper 16 and cuff 10 are
The pumping of air begins. Note that the pressure feeding of air to the air damper 16 by the electric pump 14 may be performed in step S1. In this way, if the pressure within the air damper 16 is increased in advance prior to the start of blood pressure measurement, air can be efficiently pumped into the cuff 10.

When step S3 is completed, in the following step S4, it is determined whether the actual pressure CP of the cuff 10 represented by the pressure signal SP' has become larger than a preset target upper limit pressure CP _p . and,
When it is determined that the actual pressure CP has exceeded the target upper limit pressure CP _p , step S5 is subsequently executed, the supply of the air supply control signal SC to the air supply valve drive circuit 50 is stopped, and the electromagnetic air supply is stopped. The valve 12 is closed, the supply of air to the cuff 10 is stopped, and the exhaust control signal SE to the exhaust valve drive circuit 52 is applied to the cuff 1.
The content has been changed to gradually exhaust the air inside 0,
The opening degree of the electromagnetic exhaust valve 18 is adjusted according to the contents, and the pressure within the cuff 10 is gradually lowered at a speed suitable for measuring blood pressure values.

Steps executed following step S5
In S6, the K sound signal from the A/D converter 30
Based on SK, it is determined whether a K sound has occurred. If it is determined that the K sound has not been detected yet, this step is repeated; conversely, if it is determined that the K sound has been detected, step S7 is subsequently executed to detect the K sound. The pressure CP within the cuff 10 represented by the pressure signal SP' at the time when the pressure signal SP' is reached is stored as the systolic blood pressure value. That is, the above steps S5 to S7 correspond to the systolic blood pressure value determining means of the present invention.

When the systolic blood pressure value is stored in step S7, step S8 is executed and the cuff 10 is
When the internal pressure CP becomes 10 mmHg lower than the systolic blood pressure value stored in step S7, the electromagnetic exhaust valve 1
The contents of the exhaust control signal SE are set so that the exhaust control signal SE 8 is closed. This step S8 corresponds to the blood pressure lowering means of the present invention, and thereby, the cuff pressure is lowered.
The CP is set and maintained at a pressure 10 mmHg lower than the systolic blood pressure value. When the cuff pressure CP is set to the above pressure by executing step S8, the next step S9 is executed, and the timer activation signal SS is supplied to the timer 40, so that the timer 40 starts operating. Upon completion of step S9, step S10 is subsequently executed. In step S10, the loudness of the K sound: K is detected, and in the following step S11, the loudness of the K sound: K is stored as a reference value: _Kp . Then, in the following step S12, this reference value _Kp and the systolic blood pressure value stored in step S7 are displayed and recorded on the display 54. That is, steps S10 and
S11 corresponds to the reference value determining means of the present invention.

After step S12 is completed, step S13, which is similar to step S10, is executed, a K sound corresponding to a new heartbeat is detected, and its magnitude: K is stored. Then, in the following step S14, the loudness of the K sound detected in step S13 is set to ± 100 m with the reference value K _p stored in step S11 as the center.
It is determined whether the loudness of the K sound detected in step S13 is within the permissible range (K _p ±α) of α, or whether it is larger or smaller than that range. _p ±α), step S15 is executed; if it is determined to be larger, step S16 is executed _.
If it is determined that it is within ±α), step
S17 is executed respectively.

In other words, the loudness of the K sound: K increases as the difference between the cuff pressure CP and the systolic blood pressure value of the living body increases, so the loudness of the K sound detected in step S13: K
If is larger than the allowable range (K _p ±α), cuff pressure CP will be increased by 10 mmHg, and if it is smaller than
As a result, the cuff pressure CP is controlled so that the loudness of the K sound: K matches the reference value: K _p with a tolerance of ±α.

Then, in step S17, the value obtained by adding 10 mmHg to the cuff pressure CP when the loudness of the K sound: K matches the reference value: K _p within the range of tolerance ±α is the systolic blood pressure. This systolic blood pressure value is displayed and stored on the display 54 as the living body's systolic blood pressure value in the subsequent step S18. As described above, in this embodiment, steps S13 to S16 constitute the control means of the present invention, step S17 constitutes the continuous blood pressure value determining means, and step S18 and the display 54 constitute the display means.

When the systolic blood pressure value and the volume of the K sound are displayed in step S18, step S19 is subsequently executed, and it is determined whether the blood pressure measurement time has ended. If the time-up signal SU from the timer 40 is not yet input and it is determined that the blood pressure measurement time has not ended, steps S13 and subsequent steps are repeated again to continue measuring the systolic blood pressure value of the living body. , conversely, the time-up signal SU
is input and it is determined that the blood pressure measurement time has ended, step S20 is executed and the exhaust control signal SE is
is set to fully open the electromagnetic exhaust valve 18, the electromagnetic exhaust valve 18 is fully opened, the air in the cuff 10 is rapidly exhausted, and the supply of the pump drive signal SA to the pump drive circuit 48 is stopped. . After completing step S20, the program ends.

As described above, according to the continuous blood pressure measuring device of this embodiment, the systolic blood pressure value is determined from the cuff pressure CP, which is controlled to follow the fluctuation of the systolic blood pressure value based on the magnitude of the blood flow sound K. Because of this, it is possible to measure the systolic blood pressure of a living body continuously, almost every heartbeat, in a non-invasive manner with a maximum measurement error of 10 mmHg. This has made it possible to use a non-invasive blood pressure measuring device for continuous blood pressure measurement for diagnosing autonomic nervous diseases in living organisms.

Note that in this embodiment, the cuff 10 is
Since the pressure is increased and decreased in steps of 10 mmHg, the maximum measurement error for systolic blood pressure is 10 mmHg.
However, in diagnosing autonomic nervous disorders, etc., it is sufficient to know how the systolic blood pressure value changes over time, so this level of error is quite acceptable.

Next, another embodiment of the present invention will be described. This embodiment differs from the previous embodiments only in that a second bandpass filter 24, shown by a dashed line in FIG. 3, is provided instead of the microphone 22 and first bandpass filter 28. .
The second band pass filter 24 is a pressure sensor 20
5 synchronized with the heartbeat of the living body during the pressure signal SP from
The pulse wave, which is a vibration component of ~15Hz, is detected and the pulse wave signal SM representing this pulse wave is sent to the A/D converter 3.
0. And in this example,
Instead of controlling the volume of the K sound in the above-described embodiment, the cuff pressure is controlled so that the magnitude of the pulse wave obtained as the pressure vibration of the cuff 10 synchronized with the heartbeat of the living body is constant. .

That is, to explain this in conjunction with FIG. 4 in the above-mentioned embodiment, in this embodiment, a well-known blood pressure measurement routine is executed following step S5, so that the pulse wave from the second bandpass filter 24 is measured. Based on the change in the magnitude of the signal SM, the systolic blood pressure value is determined from the pressure CP in the cuff 10 represented by the pressure signal SP', and in the subsequent step S7, the systolic blood pressure value is stored. Then, in step S10, it is determined whether or not the pulse wave signal SM has been detected instead of the K sound, and in step S11, the pulse wave signal SM is detected.
The magnitude of the pulse wave signal SM detected in S10 is stored as the pulse wave reference value SMo, and the systolic blood pressure value and its pulse wave reference value SMo are displayed in step S12.
When it is determined in step S13 that a new pulse wave signal SM has been detected, in the following step S14, the magnitude of the pulse wave signal SM is determined based on the pulse wave reference value SMo in the same manner as in the above embodiment. It is determined whether or not the blood pressure is within the specified tolerance range, and based on this determination, the systolic blood pressure value is determined in step S17. In this embodiment as well, the same effects as in the above-mentioned embodiments can be obtained. In this embodiment, the pressure sensor 20 and the second bandpass filter 24 constitute a pulse wave sensor.

Although one embodiment of the present invention has been described above in detail based on the drawings, the present invention may be implemented in other embodiments as well.

For example, in the above example, the cuff pressure CP is lowered by 10 mmHg from the systolic blood pressure value, and the magnitude of the K sound and the pulse wave are detected at this lowered cuff pressure CP, and the magnitude is constant. Cuff pressure CP has come to be controlled so that it becomes easier to detect K sounds and pulse waves as a signal that is slightly larger than the signal obtained with cuff pressure CP, which is the same as the systolic blood pressure value. This is done for the purpose of reducing measurement errors by removing noise, so it is not necessarily limited to 10 mmHg and can be changed as appropriate depending on the situation.

Furthermore, in the above embodiment, the cuff pressure CP was controlled to rise and fall every 10 mmHg.
This can also be changed as appropriate depending on the situation, such as every 5 mmHg, or the greater the difference between the reference value and the comparison value, the greater the lifting pressure. In addition, when performing pressure increase/decrease control at fixed pressure intervals,
By reducing the rising and falling pressure, the maximum measurement error of the systolic blood pressure value can be reduced and measurement accuracy can be improved; conversely, by increasing it, the ability to follow sudden changes in the systolic blood pressure value of the living body can be improved. It becomes possible.

Furthermore, in the above-mentioned embodiment, the K sound was collected as the blood flow sound, but the microphone 22 may be of a type that can detect frequency components below the audible frequency, such as a displacement microphone. subaudible frequencies of several Hz or more.
quency) pulse sound may be used instead of the K sound. The waveform of the pulse sound obtained by this type of microphone is rather close to the shape of the pulse wave described above.

Furthermore, in the above embodiment, the cuff pressure CP can be increased and decreased in order to control the cuff pressure CP, but when diagnosing autonomic nervous diseases etc., it is important to mainly look at the trend of increasing systolic blood pressure. Since this is required, the cuff pressure CP may be controlled by simply increasing the cuff pressure.

Furthermore, in the embodiment, an air damper 16 and an electromagnetic air supply valve 12 are provided between the electric pump 14 and the cuff 10.
These air dampers 16
It is also possible to omit the electromagnetic air supply valve 12.

In addition, although not listed one by one, it goes without saying that the invention of the present application can be implemented in various forms with various modifications, modifications, and improvements within the scope of the invention.

[Brief explanation of the drawing]

FIG. 1 is a claim correspondence diagram of the first invention, and FIG. 2 is a claim correspondence diagram of the second invention. FIG. 3 is a block diagram showing one embodiment of the present invention,
FIG. 4 is a flowchart illustrating the operation of the embodiment shown in FIG. {10...cuff, 12...electromagnetic air supply valve, 14...
... electric pump, 16 ... air damper, 18 ... electromagnetic exhaust valve} (compression means), {20 ... pressure sensor,
24...Second band pass filter} (pulse wave sensor), 22...Microphone, 54...Display device (display means), Steps S5 to S7...Systolic blood pressure value determining means, Step S8...Blood pressure lowering means, Step
S10 to S11... Reference value determining means, Steps S13 to S16... Control means, Step S17... Continuous blood pressure value determining means, Step S18... Display means.

Claims (1)

[Scope of Claims] 1. A non-invasive continuous blood pressure measuring device that continuously measures the blood pressure value of a living body, comprising: a compression means having a cuff for compressing a part of the living body; and compression by the compression means. a microphone for detecting blood flow sounds generated from within the living body by means of a microphone; systolic blood pressure value determining means for determining a systolic blood pressure value of the living body while changing the compression pressure of the compression means against the part of the living body; Following the determination of the systolic blood pressure value by the systolic blood pressure value determining means, a pressure lowering means for lowering the compression pressure of the compression means by a predetermined pressure below the systolic blood pressure value; a reference value determining means for determining the magnitude of the blood flow sound at the time when the blood pressure has been lowered by the amount of blood pressure as a reference value; and continuously controlling the compression pressure so that the magnitude of the blood flow sound coincides with the reference value. continuous blood pressure value determining means for continuously determining the systolic blood pressure value of the living body based on the compression pressure continuously controlled by the controlling means; A non-invasive continuous blood pressure measuring device comprising: a display means for continuously displaying a hypertension value; and a non-invasive continuous blood pressure measuring device. 2. A non-invasive continuous blood pressure measurement device that continuously measures the blood pressure value of a living body, comprising a compression means having a cuff for compressing a part of the living body, and a pressure of the cuff that is synchronized with the heartbeat of the living body. a pulse wave sensor that detects a pulse wave which is a vibration; a systolic blood pressure value determining means that determines a systolic blood pressure value of the living body while changing the compression pressure of the compression means against the part of the living body; and systolic blood pressure value determining means blood pressure lowering means for lowering the compression pressure of the compression means by a predetermined pressure below the systolic blood pressure value following the determination of the systolic blood pressure value by the means; and a time point when the compression pressure is lowered by the predetermined pressure by the pressure lowering means. a reference value determining means for determining the magnitude of the pulse wave as a reference value; a control means for continuously controlling the compression pressure so that the magnitude of the pulse wave coincides with the reference value; continuous blood pressure value determining means for continuously determining the systolic blood pressure value of the living body based on compression pressure continuously controlled by the means; and continuously displaying the systolic blood pressure value determined by the continuous blood pressure value determining means. A non-invasive continuous blood pressure measuring device characterized by comprising: a display means for displaying, and a display means for displaying.