JP2003225213A - Apparatus for measuring blood pressure and electromagnetic type exhaust valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To be easily adaptable for various sizes of cuffs and subjects on which blood pressure is measured. <P>SOLUTION: An apparatus is provided with a generating circuit 54 for characteristically reducing reference pressure which generates a straight line for characteristically reducing the reference pressure linearly with a constant gradient with the elapse of time from the base point having the maximum pressure exerted by a cuff 1, a pulse wave erasing circuit 53 for generating a pulse wave erasing pressure signal in which a component of the pulse wave is erased or attenuated from the pressure of the cuff 1, an electromagnetic exhaust valve control circuit 56 in which a difference is taken between respective reference reduction signals per each certain time, obtained from the line for characteristically reducing the reference pressure, and the pulse wave erasing pressure signal of the cuff per each time, and when the pulse wave erasing pressure signal is large, a control for increasing the degree of opening of an exhaust valve 3 is carried out and when the pulse wave erasing pressure signal is small, a control for reducing the degree of opening of the exhaust valve 3 is carried out based on the different, and an pulse wave signal processing circuit 52 for extracting signals required for blood pressure measurement from the pressure of the cuff 1 which the pulse wave is superposed upon and is capable of regenerating the approximate original waveform of the pulse wave. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a blood pressure measuring device having an exhaust valve and an electromagnetic exhaust valve.

[0002]

2. Description of the Related Art A non-invasive blood pressure monitor that has been conventionally used is one in which a cuff is wrapped around an arm or the like to inject air into the cuff to increase the pressure, and then a pulse wave is generated while exhausting the air in the cuff. Is generally observed.

In such a sphygmomanometer, a constant speed exhaust valve is used as an exhaust valve for exhausting the air in the cuff, and a rubber valve or the like is used as the constant speed exhaust valve to perform opening / closing control. There is an electric constant speed exhaust valve that electrically controls opening and closing by using a mechanical constant speed exhaust valve and a solenoid valve.

As the former mechanical constant-speed exhaust valve, there is one that controls the opening and closing of the valve by utilizing expansion of a rubber valve. For example, when the air exhausted from the cuff is introduced into the constant speed exhaust valve, when the pressure becomes high, the rubber valve expands and the exhaust port of the constant speed exhaust valve is throttled to perform control to reduce the exhaust amount. This reduces the decompression rate, and conversely, when the pressure is low, the rubber valve does not expand, so the exhaust port of the constant speed exhaust valve is opened, and by increasing the displacement, a constant decompression rate is achieved. Exhaust speed control such as securing is performed. As a result, a constant depressurization rate can be obtained regardless of the pressure of the cuff.

On the other hand, the latter electric constant speed exhaust valve generally controls the opening and closing of the valve by an electromagnetic coil. An example of the constant speed exhaust valve using such an electromagnetic valve is as follows. For example, there is one as disclosed in Japanese Patent Laid-Open No. 4-250133. The constant speed exhaust valve disclosed in Japanese Patent Laid-Open No. 4-250133 closes the electromagnetic valve for exhaust when the component showing the pulse wave in the cuff appears, and stops the exhaust,
The constant speed exhaust valve is electrically controlled such that exhaust is performed when the pulse wave disappears.

[0006]

In the mechanical constant-speed exhaust valve using the former rubber valve, the rubber valve is easily affected by the ambient temperature because of its material, and the rubber valve hardens or softens due to temperature changes. Therefore, there is a problem that the decompression speed fluctuates even if there is a slight temperature change, and a large difference occurs in the exhaust time.

This evacuation time also depends on the size of the cuff. That is, a larger cuff requires more exhaust time. Therefore, if the exhaust time fluctuates due to the temperature change, more fluctuations may occur depending on the size of the cuff.
Since blood pressure measurement objects may range from small experimental animals to humans and even larger animals, it is a big problem that the exhaust time changes due to changes in temperature.

In the latter electric constant speed exhaust valve (constant speed exhaust valve disclosed in Japanese Patent Laid-Open No. 4-250133), as shown in FIG. 6, the component W0 indicating the pulse wave in the cuff is not generated. When it appears, exhaust control is repeated by closing the electromagnetic valve for exhaust and stopping exhaust, and performing exhaust (constant speed exhaust) when the pulse wave disappears.

A constant speed exhaust valve using such a solenoid valve is
Unlike the constant-speed exhaust valve using the rubber valve described above, it is unlikely to be affected by temperature changes, etc., but only the pulse wave component W0 is used to perform differential processing to calculate the blood pressure value. There is. That is, in this conventional technique, as can be seen from FIG. 6, only the pulse wave W0 obtained with the exhaust gas stopped is used as a signal for measuring the blood pressure, and the pulse wave component W0 is kept constant. Since the fast exhaust region is represented only by an approximate straight line, there is a problem that information about the pulse wave component in that portion cannot be obtained.

This means that the pulse wave components necessary for measuring the blood pressure value are important not only for the respective pulse wave components W0 shown in FIG. 6 but also for the pulse wave components existing between these pulse waves W0. This is because information may be included.
Therefore, it is desirable to be able to reproduce the original waveform of the pulse wave.

Further, the above-mentioned conventional electric constant speed exhaust valve performs the opening and closing operations of the exhaust valve at the time of detecting the pulse wave, but since the pulse wave itself is usually minute, the exhaust at the time of detecting the pulse wave is performed. When the valve opening and closing operations are performed, a large pressure fluctuation occurs as compared with the pulse wave, which causes the original pulse wave waveform to be difficult to detect. That is, there is a problem that pressure fluctuations (vibrations) other than the pulse wave occur as noise at the moment when the exhaust valve is fully opened and at the moment when the exhaust valve is fully closed, and the noise is detected as an extra pulse wave signal.

Further, this conventional electric constant-speed exhaust valve cannot handle various cuff sizes, like the mechanical constant-speed exhaust valve described above.

Therefore, the present invention has been made in order to solve the above-mentioned problems, can extract a pulse wave close to the original waveform of the pulse wave, and limits the size of the cuff and the blood pressure measurement target. Device capable of adapting to various cuff sizes and blood pressure measurement targets without needing to take out a pulse wave close to the original waveform of the pulse wave, and an electromagnetic exhaust valve used in the device. Is intended to provide.

[0014]

In order to achieve the above-mentioned object, the blood pressure measuring apparatus of the present invention has a pressurizing means for pressurizing the cuff, and a pulse wave is superposed after pressurizing by the pressurizing means. An exhaust valve that reduces the pressure of the cuff, a pressure detection unit that detects the pressure of the cuff, and a pressure detection that is obtained from the pressure detection unit when the exhaust valve operates to reduce the pressure of the cuff on which the pulse wave is superimposed. A blood pressure measurement device having a blood pressure measurement signal processing means for measuring a blood pressure value based on a signal, wherein the blood pressure measurement signal processing means is based on a pressure value when the cuff is pressurized to a predetermined pressure by the pressurizing means. , A reference decompression characteristic generating means for generating a reference decompression characteristic straight line that has a certain inclination and linearly decompresses with time, and a pulse wave component is eliminated from the pressure of the cuff on which the pulse wave is superimposed. The pulse wave component is eliminated or attenuated Pulse wave elimination means for generating a pulse wave elimination pressure signal, a reference decompression signal for each time obtained from the reference decompression characteristic line, and the difference between the cuff pulse wave component elimination pressure signal at that time, and the reference If the cuff pulse wave component elimination pressure signal is greater than the pressure reduction signal, control is performed to increase the opening of the exhaust valve based on the difference, and the cuff pulse wave component elimination pressure signal is greater than the reference pressure reduction signal. When is small, the exhaust valve control means for controlling the opening degree of the exhaust valve based on the difference, the exhaust valve control means for controlling the opening degree of the pulse wave, and the superposition of pulse waves. And a pulse wave signal processing means for processing the pressure of the cuff thus generated to extract a signal required for blood pressure measurement.

As described above, by controlling the exhaust valve by using the pressure of the cuff (pulse wave elimination pressure) in which the pulse wave is eliminated or attenuated, it is possible to perform the exhaust control which is hardly influenced by the pulse wave. In addition, since the exhaust control at this time is performed along the set reference decompression characteristic straight line, a constant exhaust control can be performed regardless of the size of the cuff.

Further, in the present invention, the reference decompression characteristic generating means can generate a reference decompression characteristic straight line having an arbitrary inclination, and the magnitude of the inclination can be set according to the heart rate of the blood pressure measurement object. I have to. This allows a person to intentionally create a reference decompression characteristic straight line having an arbitrary inclination. The inclination can be set according to the heart rate.

For example, for an animal such as a mouse having a large heart rate, the number of pulse waves necessary for the diagnosis of blood pressure measurement can be obtained even if the inclination is large (the decompression rate is large). It is possible to generate a large reference decompression characteristic straight line, and conversely, for an animal with a low heart rate, in order to obtain the number of pulse waves necessary for diagnosis of blood pressure measurement, the slope is made small (the decompression rate is Since it is necessary to generate a (decreased) reference decompression characteristic line, it is possible to create a reference decompression characteristic line with a small slope, so that the inclination can be set arbitrarily according to the heart rate of the measurement target. it can. This makes it possible to adapt to a wide range of blood pressure measurement targets having various heart rates, such as small animals for experiments, humans, and even larger animals.

The pulse wave signal processing means receives the reference reduced pressure signal from the reference reduced pressure characteristic generating means, takes the difference from the reference reduced pressure signal from the pressure signal of the cuff on which the pulse wave is superimposed, and based on the difference. Thus, it is preferable to have a pulse wave reproduction processing means for reproducing an approximate original waveform of the pulse wave. As a result, a waveform close to the original waveform of the pulse wave can be obtained, and thus more detailed information regarding the blood pressure value may be obtained, and it is expected that more accurate blood pressure measurement results will be obtained.

The exhaust valve used in the blood pressure measuring device is an electromagnetic exhaust valve, which is a cylindrical electromagnetic coil and is inserted into the hollow portion of the cylindrical electromagnetic coil so as to extend in the direction of the central axis of the electromagnetic coil. The movable body has a disk-shaped collar part for receiving the pressure of the air exhausted from the cuff at the tip of the movable body which is reciprocally movable along the Elastic body that applies a biasing force to the movable body, a cylindrical casing that houses these electromagnetic coils, the movable body, and the elastic body, and concentric circles on the inner end surface of the casing that faces the flange of the movable body. Provided on at least one of the provided at least two O-rings having different diameters, the exhaust introduction port connected to the cuff provided between these O-rings, the side surface of the cylindrical casing, and the end surface on the side where the O-ring is provided. Exhaust Preferably a structure having and.

With such a structure, it is possible to widen the air circulation space inside the electromagnetic exhaust valve and to efficiently exhaust the air to the outside of the electromagnetic exhaust valve, so that the pressure of the cuff is low. Even at this time, a large amount of air can be exhausted by a minute change in the movable body. Further, since the electromagnetic exhaust valve has the exhaust introduction port provided between the O-rings, in the fully closed state, it has a structure in which the pressure from the cuff is received only by the portions surrounded by the O-rings. As a result, even though the entire flange portion of the movable body is large, the area that receives pressure is only a very limited portion, so when in the fully closed state, the fully closed state is maintained with a slight electromagnetic force. be able to.

The electromagnetic exhaust valve of the present invention is provided with a cylindrical electromagnetic coil and a cylindrical electromagnetic coil inserted in the hollow portion of the cylindrical electromagnetic coil so as to reciprocate along the central axis direction of the electromagnetic coil. , A movable body having a disk-shaped collar portion for receiving the pressure of air entering the inside at its tip, and an urging force in the direction opposite to the urging force given to the movable body by the electromagnetic coil, are applied to the movable body. An elastic body to be given, a cylindrical casing for housing these electromagnetic coil, movable body, and elastic body, and at least two concentrically different diameters provided concentrically on the inner end face of the movable body facing the flange portion. O-ring, an exhaust inlet provided between these O-rings, and an exhaust outlet provided on at least one of the cylindrical housing side surface surrounding each member and the end surface on the side where the O-ring is provided. There is.

With such a structure, it is possible to widen the air circulation space inside the electromagnetic exhaust valve and to efficiently exhaust the air to the outside of the electromagnetic exhaust valve. When used for air supply control, a large amount of air can be exhausted by a slight change in the movable body. In addition, this electromagnetic exhaust valve has a structure in which the exhaust introduction port is provided between the O-rings, so that in the fully closed state, the pressure of the fluid such as incoming air is received only by the parts surrounded by the O-rings. Has become. As a result, even though the entire flange portion of the movable body is large, the area that receives pressure is only a very limited portion, so when in the fully closed state, the fully closed state is maintained with a slight electromagnetic force. be able to.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 is a block diagram of an electronic sphygmomanometer 10 which is a blood pressure measuring device of the present invention. This electronic blood pressure monitor 10
Is a cuff 1 and a pressure sensor serving as a pressure detection unit that detects the pressure in the cuff 1 and outputs a signal corresponding to the pressure (in this case, the voltage value is expressed as a pressure signal here). 2, an electromagnetic exhaust valve 3 as an exhaust valve for exhausting the pressure in the cuff 1, a pressurizing pump 4 as a pressurizing means for pressurizing the inside of the cuff 1, and an electromagnetic exhaust valve for driving the pressurizing pump 4. It has a blood pressure measurement signal processing unit 5 for performing exhaust control of No. 3 and generating a control signal for the electromagnetic exhaust valve 3 based on a pressure signal from the pressure sensor 2 and performing signal processing necessary for blood pressure measurement.

The blood pressure measurement signal processing section 5 includes a pressure amplifier 5
1. Control a pulse wave signal processing circuit 52 that serves as pulse wave signal processing means, a pulse wave elimination circuit 53 that serves as pulse wave elimination means, a reference pressure reduction characteristic generation circuit 54 that serves as reference pressure reduction characteristic generation means, and internal circuits. Control computer 55, electromagnetic exhaust valve control circuit 56 serving as exhaust valve control means, pressurizing pump drive circuit 5
7, a display / operation key unit 58 and the like.

The pressure amplifier 51 amplifies the pressure signal in the cuff 1 detected by the pressure sensor 2 (which is a pressure signal on which a pulse wave is superposed, and hence will be referred to as a pulse wave superposed pressure signal hereinafter). Therefore, the amplified pulse wave superimposed pressure signal in the cuff 1 is passed to the pulse wave signal processing circuit 52, the pulse wave erasing circuit 53, and the reference decompression special pressure generation circuit 54.

The reference depressurization characteristic generation circuit 54 obtains a control signal from the control computer 55 to generate a reference depressurization characteristic straight line having a certain inclination, and serves as a reference depressurization characteristic generation means. That is, for example, as shown in FIG. 2, the pressurizing pump 4 pressurizes the inside of the cuff 1 up to a predetermined pressure (maximum pressure Pmax), and then has a gradient with the maximum pressure value Pmax as a base point. A reference decompression characteristic line in which the pressure is linearly reduced to 0 mmHg with the passage of time is generated.

The reference decompression characteristic line is also represented as a change in voltage value in this case. The value obtained from this reference decompression characteristic line will be referred to as a reference decompression signal. Further, in actuality, a stabilization time Δt for stabilizing the pressure is provided before the pressure starts to be reduced from the maximum pressure value Pmax, and after this Δt, a reference decompression characteristic straight line in which the pressure is reduced to 0 mmHg is generated. In FIG. 2, the reference decompression characteristic straight line is denoted by So.

The magnitude of the inclination of the reference pressure reducing characteristic line So, that is, the magnitude of the pressure reducing speed can be freely set by the control computer 55. This depressurization rate can be set according to the blood pressure measurement target, and here it is set according to the heart rate of the measurement target.

For example, the heart rate of human beings is usually about 60 to 70 times per minute, but the heart rate of experimental mice is about 10 times that of humans. It is known that it is about 30 times, which is much less than the above.

In any case, it is necessary to extract a pulse wave number above a certain level in order to perform an appropriate blood pressure measurement. That is, if the heart rate is large, even if the inclination of the reference decompression characteristic line So is increased, the number of crossings with the pulse wave superimposed pressure waveform from the cuff 1 increases, so that a sufficient number of pulse waves can be extracted. When the heart rate is low, the reference decompression characteristic straight line S is used to increase the number of intersections with the pulse wave superimposed pressure waveform from the cuff 1.
It is necessary to reduce the inclination of o.

Therefore, for a small animal with a high heart rate, the required pulse wave rate can be secured even if the inclination of the reference decompression characteristic line So is increased to some extent, but for an animal with a low heart rate, the reference decompression characteristic line So is obtained. The required pulse wave number cannot be obtained unless the slope of So is reduced.

As described above, the size of the inclination of the reference decompression characteristic line So can be set so that it can be applied to various measurement targets. The size of the inclination can be arbitrarily set by the control computer 55.

The reference pressure reduction characteristic line So generated by the reference pressure reduction characteristic generation circuit 54 is passed to the pulse wave signal processing circuit 52 and the electromagnetic exhaust valve control circuit 56.

By the way, the pulse wave elimination circuit 53 described above
The pulse wave component is eliminated or attenuated to such an extent that the pulse wave remains in the pulse wave superimposed pressure signal in the cuff 1 amplified by the pressure amplifier 51, and the pulse wave is eliminated or the pulse wave slightly remains. The pressure signal in the cuff 1 that has been attenuated to a certain degree (hereinafter, simply referred to as elimination or attenuation) is passed to the electromagnetic exhaust valve control circuit 56. The pressure in the cuff 1 from which the pulse wave has been eliminated or attenuated will be referred to as the pulse wave elimination pressure of the cuff 1 here.

As described above, if the pulse wave eliminated or attenuated pressure signal of the cuff 1 (pulse wave eliminated pressure signal) is passed to the electromagnetic exhaust valve control circuit 56, if the pulse wave is superposed. When the electromagnetic exhaust valve 3 is controlled using the pressure signal of the cuff 1 (pulse wave superimposed pressure signal) as it is, when a portion having a value larger than the reference decompression characteristic line So exists in the pulse wave, This is because if the pressure reduction control is performed in accordance with a portion having a large value, and then the pulse wave falls, the pressure may be reduced too much for the falling portion.

The electromagnetic exhaust valve control circuit 56 uses the reference pressure reduction characteristic straight line So generated by the reference pressure reduction characteristic generation circuit 54.
And a pulse wave erasing pressure signal in the cuff 1 whose pulse wave is erased or attenuated by the pulse wave erasing circuit 53 generates a signal for driving the electromagnetic exhaust valve 3 (pulse width modulation signal). The electromagnetic exhaust valve 3 is controlled. The control of the electromagnetic exhaust valve 3 will be described later.

The pulse wave signal processing circuit 52 includes a pressure amplifier 51.
The pulse wave component is extracted from the pulse wave superimposed pressure signal in the cuff 1 obtained via the signal and the pulse wave component is processed to reproduce the original waveform of the pulse wave. A differentiated waveform obtained by differentiating the waveform (a conventional blood pressure measurement signal) is obtained and passed to the control computer 55.

The process of extracting the pulse wave component from the pulse wave superimposed pressure signal in the cuff 1 is approximated by subtracting the reference decompression signal from the pulse wave superimposed pressure signal in the cuff 1 obtained via the pressure amplifier 51. However, the pulse wave component can be extracted. Then, the extracted pulse wave component is subjected to predetermined signal processing (pulse wave reproduction processing) by a pulse wave reproduction processing circuit (not shown) provided in the pulse wave signal processing circuit 52 to obtain the original pulse wave. A waveform very close to the wave (original waveform of the pulse wave) can be reproduced.

The pulse wave reproduced here becomes an approximate original waveform due to the influence of the moment of inertia by the electromagnetic exhaust valve 3, friction, non-linearity of the magnetic circuit of the electromagnetic exhaust valve 3 and circuit characteristics. The waveform has sufficient accuracy to be regarded as the original waveform of the pulse wave.

3A and 3B show the structure of the electromagnetic exhaust valve 3. FIG. 3A is a side sectional view, and FIG. 3B is a sectional view taken along line XX of FIG.

The electromagnetic exhaust valve 3 is generally a cylindrical electromagnetic coil 31, and can reciprocate in the hollow portion of the electromagnetic coil 31 in the direction of arrow yy ', and has a disk-shaped collar at one end. Columnar movable body 32 in which the portion 32a is formed, the electromagnetic coil 3
1 has a cylindrical first casing 33 which is housed inside and one end of which is an opening, and an opening end portion of which is joined to the opening end portion of the cylindrical first casing 33 on one end side thereof, First housing 3
The second casing 34 has a cylindrical shape and is joined in an airtight state with the open end of the third casing 34.

On the inner end surface of the second housing 34, two O-rings 35 and 36 having different diameters are arranged so as to draw concentric circles on the inner end surface of the second housing 34. The O-ring 35 having the larger diameter is provided on the flange 32 of the movable body 32.
The O-ring 36 having a diameter slightly smaller than the outer diameter of a and having a smaller diameter has a diameter such that the pressure receiving portion 37 is formed between the O-ring 36 and the O-ring 35.

Then, these two O-rings 35, 3
An exhaust inlet 38 for exhausting air from the cuff 1 is formed in the pressure receiving portion 37 formed between the cuffs 6. The exhaust introduction port 38 is connected to the cuff 1 by an air tube (not shown).

Further, the second housing 34 is provided with exhaust ports 39 and 40 on its end face and side wall face, respectively, so that the air entered from the exhaust introduction port 38 can be discharged to the outside. ing. It is preferable that both the exhaust port 39 provided on the end face and the exhaust port 40 provided on the side wall face are provided in terms of exhaust efficiency, but there is a case where only one of them may be provided.

Further, the movable body 32 is formed with a hollow portion 32b from the end face of the flange portion 32a along the central axis thereof.
A coil spring 41, which is an elastic body, is inserted into the hollow portion 32b. One end side of the coil spring 41 (right side of FIG. 3)
Is projecting outward from the movable body 32 by a predetermined amount, and its projecting end is fitted in a recess 34a provided in the inner wall of the lid 34. The coil spring 41 exerts a pressing force (biasing force) in the arrow y direction on the movable body 32 by its extension force.

That is, the movable body 32 is in a state in which the flange portion 32a is separated from the O-rings 35 and 36 in a state where no current flows in the electromagnetic coil 31, and the electromagnetic exhaust valve 3
Is in the fully open state. The electromagnetic exhaust valve 3 is
Opening degree (opening degree) by the electromagnetic exhaust valve control circuit 56
Is controlled.

That is, the electromagnetic exhaust valve 3 is in a state where air is sent into the cuff 1 by the pressurizing pump 4, that is,
When the cuff 1 is pressurized, the electromagnetic exhaust valve control circuit 5
It is controlled by 6 to be in a fully closed state as shown in FIG. On the other hand, after the cuff 1 is pressed, the cuff 1
When the exhaust is performed, the opening degree of the valve is controlled by the electromagnetic exhaust valve control circuit 56. This valve opening control will be described later.

The operation of the electronic blood pressure monitor 10 having such a configuration will be described.

First, the control computer 55 operates the reference pressure reduction characteristic generation circuit 54 to generate the reference pressure reduction characteristic line. For example, assume that the reference decompression characteristic line So having the inclination as shown in FIG. 2 is generated. The reference depressurization characteristic line So is actually represented as a temporal change in the voltage value that linearly decreases with the voltage value corresponding to the maximum pressure value Pmax in the cuff 1 as a base point.

FIG. 4 shows the reference decompression characteristic line So generated by the reference decompression characteristic generation circuit 54 and the pulse wave superimposed pressure curve Sw in the cuff 1. The pulse wave superimposed pressure curve Sw of the cuff 1 is shown in FIG.
Is actually extracted as a change in voltage value corresponding to pressure.

The pulse wave superimposed pressure curve Sw in the cuff 1 shown in FIG. 4 is obtained by discharging a certain fixed amount from the maximum pressure Pmax when the cuff 1 is pressurized by the pressurizing pump 4. 7 shows a pulse wave superimposed pressure curve Sw in a part of the cuff 1 after the start of the flow. In FIG. 4, the pulse wave superimposed pressure curve Sw in the cuff 1 is decompressed while oscillating up and down because a pulse wave component appears. The decompression characteristic (exhaust curve) becomes almost linear.

Now, assume that the pressure amplifier 51 outputs a pulse wave superimposed pressure signal corresponding to the pulse wave superimposed pressure curve Sw of the cuff 1 as shown in FIG. The pulse wave superimposed pressure signal of the cuff 1 is applied to the pulse wave elimination circuit 53 and the pulse wave signal processing circuit 5.
Passed to 2. In the pulse wave elimination circuit 53, the pulse wave component is eliminated from the pulse wave superimposed pressure signal of the cuff 1 (actually, not a completely eliminated state but a state in which some pulse waves remain), and the cuff 1 is removed. To obtain the pulse wave elimination pressure signal.

On the other hand, in the pulse wave signal processing circuit 52, when the pulse wave superimposed pressure signal of the cuff 1 as shown in FIG. 4 is received from the pressure amplifier 51, the differential waveform obtained by differentiating the pulse wave superimposed pressure signal (from the conventional one) A blood pressure measurement signal) is obtained, blood pressure measurement processing is performed on the control computer 55, and the result is displayed on the display screen of the display / operation key unit 58.

Further, when the pulse wave signal processing circuit 52 receives the pulse wave superimposed pressure signal from the pressure amplifier 51, the reference pressure reducing characteristic straight line S generated by the reference pressure reducing characteristic generating circuit 54 is obtained.
As described above, the pulse wave component is extracted using the reference decompression signal obtained from o, and the extracted pulse wave component is subjected to predetermined pulse wave regeneration processing. It is possible to reproduce a waveform very close to (waveform).

The pulse wave reproduced here is, as described above, the original pulse due to the influence of the moment of inertia by the electromagnetic exhaust valve 3, friction, non-linearity of the magnetic circuit of the electromagnetic exhaust valve, and circuit characteristics. Although it is an approximate pulse wave for a wave, it has a sufficient accuracy to be regarded as the original waveform of the pulse wave.

In other words, the pulse wave reproduced here can be a waveform of at least one cycle of the pulse wave itself,
As in the prior art (see FIG. 6), the inconvenience that the information between the pulse waves W0 cannot be acquired can be eliminated. In this way, by reproducing a waveform close to the original waveform of the pulse wave and passing the reproduced original waveform of the pulse wave to the control computer 55, waveform analysis or the like can be performed on the control computer 55. The information obtained by the waveform analysis can be used for the diagnosis of blood pressure measurement and can be used for other diagnosis.

Next, the control of the electromagnetic exhaust valve 3 which is an electromagnetic exhaust valve will be described.

The electromagnetic exhaust valve 3 is operated by an electromagnetic exhaust valve control circuit 56. In the electromagnetic exhaust valve control circuit 56, the pulse wave elimination signal of the cuff 1 which has been subjected to the pulse wave elimination processing by the pulse wave elimination circuit 53 and the reference decompression characteristic generation circuit 54.
And the reference depressurization signal from the control unit, and the electromagnetic exhaust valve 3 is controlled based on these signals. The control of the electromagnetic exhaust valve 3 will be described below with reference to FIG.

The reference pressure reduction signal characteristic So shown in FIG.
Is the same as that shown in. It is assumed that the pulse wave elimination signal of the cuff 1 at time t1 is Sc1, and the reference pressure reduction signal obtained from the reference pressure reduction signal characteristic So is So1. Therefore, at the time t1, the electromagnetic exhaust valve control circuit 56 informs the cuff 1 of the pulse wave elimination signal Sc1 and the reference pressure reduction signal S.
o1 is given.

As a result, in the electromagnetic exhaust valve control circuit 56, the pulse wave elimination signal Sc1 of the cuff 1 and the reference pressure reducing signal S
The difference of o1 is calculated, and the opening degree of the electromagnetic exhaust valve 3 corresponding to the difference is controlled. That is, when the pulse wave elimination signal Sc1 of the cuff 1 is larger than the reference pressure reducing signal So1, control is performed to increase the opening degree of the electromagnetic exhaust valve 3 based on the difference, and conversely, the pulse wave elimination signal of the cuff 1 is eliminated. When the signal Sc1 is smaller than the reference pressure reduction signal So1, control is performed to reduce the opening degree of the electromagnetic exhaust valve 3 based on the difference.

For example, as shown in FIG. 5, at time t1, the pulse wave elimination signal Sc1 of the cuff 1 is changed to the reference reduced pressure signal S.
If it is larger than o1, control is performed to increase the opening degree of the electromagnetic exhaust valve 3 based on the difference. As a result, the pulse wave superimposed pressure of the cuff 1 is reduced (the arrow x1 in FIG. 5) because the pressure is exhausted more.

Thereafter, at time t2, the same processing as described above is performed. That is, at time t2, the difference between the pulse wave elimination signal Sc2 of the cuff 1 and the reference pressure reduction signal So2 is obtained, and as a result, the pulse wave elimination signal S of the cuff 1 is still present at this point.
If c2 is greater than the reference pressure reduction signal So2, control is performed to increase the opening degree of the electromagnetic exhaust valve 3 based on the difference. As a result, the pulse wave superimposed pressure of the cuff 1 is
Further exhaustion causes the pressure to decrease further (arrow x2 in FIG. 5).

At time t3, the difference between the pulse wave elimination signal Sc3 of the cuff 1 and the reference pressure reduction signal So3 is obtained. As a result, the pulse wave elimination signal Sc3 of the cuff 1 is at a higher level than the reference pressure reduction signal So3 at this time. If it becomes smaller, the opening degree of the electromagnetic exhaust valve 3 is controlled based on the difference. As a result, the exhaust amount of the pulse wave superimposed pressure of the cuff 1 is suppressed and the degree of pressure decrease is reduced (arrow x in FIG. 5).
3).

Subsequently, at time t4, the difference between the pulse wave elimination signal Sc4 of the cuff 1 and the reference reduced pressure signal So4 is obtained. As a result, at this time point, the pulse wave elimination signal Sc4 of the cuff 1 and the reference reduced pressure signal So4 are obtained. If the difference is zero, the opening degree of the electromagnetic exhaust valve 3 is controlled so as to maintain that state. As a result, the exhaust of the cuff 1 having the superimposed pulse wave pressure is maintained in the same state as at the time t3 (arrow x in FIG. 5).
4).

Subsequently, at time t5, assuming that the pulse wave elimination signal Sc5 of the cuff 1 is larger than the reference pressure reduction signal So5 as a result of taking the difference between the pulse wave elimination signal Sc5 of the cuff 1 and the reference pressure reduction signal So5. Control is performed to increase the opening degree of the electromagnetic exhaust valve 3 based on the difference. As a result, the pulse wave superimposed pressure of the cuff 1 decreases in the direction in which the pressure is decreased by discharging more (arrow x5 in FIG. 5).

By repeating the opening control of the electromagnetic exhaust valve 3 as described above, the pulse wave superimposed pressure of the cuff 1 is reduced along the reference pressure reduction characteristic line So. Since this reference decompression characteristic line So can be intentionally created by a human, it is possible to set an arbitrary inclination, and a decompression characteristic along the reference decompression characteristic line So having the arbitrary inclination is obtained. Will be able to.

Thus, for example, if the reference decompression characteristic line So having the inclination as shown in FIG. 4 is set, the pulse wave superimposed pressure of the cuff 1 will be no matter what size the cuff 1 is used. Since the pressure is reduced according to the pressure reduction characteristic along the reference pressure reduction characteristic line So, the pressure reduction characteristic along the set reference pressure reduction characteristic line So can be obtained regardless of the size of the cuff 1. As a result, it can be applied to cuffs 1 of various sizes.

Further, by setting various inclinations of the reference decompression characteristic line So, it is possible to apply to measurement objects having various heart rates (heart rate per unit time).

For example, for an animal such as a mouse with a large heart rate, the number of pulse waves necessary for the diagnosis of blood pressure measurement can be obtained even if the gradient is large (the decompression rate is large). It is possible to generate a large reference decompression characteristic line So, and conversely, for an animal with a low heart rate,
In order to obtain the number of pulse waves necessary for the blood pressure measurement diagnosis, the reference decompression characteristic line So with a small slope (small decompression rate)
Since it is necessary to generate the reference decompression characteristic line So having a small inclination, it is possible to arbitrarily set the inclination according to the heart rate of the measurement target. This makes it possible to adapt to a wide range of blood pressure measurement targets having various heart rates, such as small animals for experiments, humans, and even larger animals.

For example, when considering a blood pressure monitor for measuring blood pressure in humans, the size of the cuff 1 to be used is usually different depending on the difference in the size of the arm and the like between adults and children. is there. In such a case, the slope of the reference decompression characteristic line So is made to match the standard heart rate of a human (about 60 to 70 times per minute), and the reference decompression characteristic line So is used for the above-mentioned inclination. By performing the solenoid valve control as described above, the exhaust is performed at the decompression rate along the reference decompression characteristic line So regardless of whether it is the adult cuff 1 or the child cuff 1. The number of pulse waves required for diagnosis of blood pressure measurement can be obtained regardless of the size of the pulse wave.

Further, for measurement objects having greatly different heart rates, the reference decompression characteristic line So is set to an inclination suitable for the heart rate of each measurement object, so that the heart rate of each measurement object can be adjusted. Since the exhaust is performed at the decompression rate, the number of pulse waves required for the diagnosis of blood pressure measurement can be obtained in that case as well, regardless of the size of the cuff 1.

If the inclination of the reference decompression characteristic line So can be easily set by key input of the control computer 55, the heart rate at the start of measurement is measured for each individual measurement subject, and at that time. It is also possible to set the slope of the reference decompression characteristic line So according to the heart rate of the. According to this, the optimum reference decompression characteristic line So corresponding to the heart rate at that time is obtained, and the blood pressure can be measured using the reference decompression characteristic line So, so that more appropriate blood pressure measurement is possible. .

Further, the electromagnetic exhaust valve 3 used in the present embodiment is controlled by the electromagnetic exhaust valve control circuit 56 as described above. The control will be made with reference to the structure shown in FIG. explain.

In the state of FIG. 3, the electromagnetic exhaust valve 3 is fully closed (the movable body 32 receives the electromagnetic force of the electromagnetic coil 31 and resists the extension force of the coil spring 41, so that the two O-rings 35 are provided. , 36), and this state is
This is the case where the cuff 1 is pressurized by the pressure pump 4.
In the subsequent exhausting state, the movable body 32 of the electromagnetic exhaust valve 3 is separated from the two O-rings 35 and 36, and the electromagnetic exhaust valve 3 is in the open state.
The opening degree is controlled by the electromagnetic exhaust valve control circuit 56.

That is, at time t1 in FIG. 5, it is necessary to control the exhaust amount to be large, that is, to increase the opening. In that case, the movable body 32 is changed from the state of the opening at that time. Is controlled to move slightly in the direction of arrow y. As a result, the air from the cuff 1 passes through the pressure receiving portion 37 formed between the two O-rings 35 and 36, and reaches the exhaust port 39 provided on the end surface of the second housing 34 and the side wall surface. The gas is exhausted from both of the exhaust ports 40 provided.

Similarly, at time t2, control is performed so as to increase the displacement, that is, the opening is required to be larger, so that the movable body 32 is moved slightly in the direction of arrow y. Is done. As a result, the air from the cuff 1 passes through the pressure receiving portion 37 formed between the two O-rings 35 and 36 and is exhausted from both the exhaust port 39 and the exhaust port 40. The degree of displacement is slightly larger than that after time t1.

At time t3, control is performed to reduce the exhaust gas amount, that is, the opening is required to be narrower than at the present time, so that control is performed so that the movable body 32 slightly moves in the arrow y'direction. Also in this case, the air from the cuff 1 passes through the pressure receiving portion 37 formed between the two O-rings 35 and 36 and is exhausted from both the exhaust port 39 and the exhaust port 40. The amount becomes smaller than the exhaust amount after time t2.

As described above, the electromagnetic exhaust valve 3 controls the exhaust amount in accordance with the moving amount of the movable body 32. The electromagnetic exhaust valve 3 has an air circulation space inside the electromagnetic exhaust valve 3 (see FIG. 3). Then, the space after passing through the pressure receiving portion 37 formed between the two O-rings 35, 36) is wide. That is, air flows out from each part of the entire circumference of the O-rings 35 and 36. Moreover, in this case, as the exhaust port to the outside, the exhaust port 39 provided on the end face of the second housing 34 and the exhaust port 40 provided on the side wall face are present, so that even when the pressure of the cuff 1 is low. A large amount of air can be exhausted by only slightly changing the movable body 32.

When the electromagnetic exhaust valve 3 is in the fully closed state, the pressure from the cuff 1 is received only by the pressure receiving portion 37 formed between the two O-rings 35 and 36. As a result, although the flange portion 32a of the movable body 32 has a disk shape and the entire area thereof is large, the pressure receiving area is only a very limited portion (only the pressure receiving portion 37). In the fully closed state, that is, the action of the electromagnetic coil 31 resists the extension force of the coil spring 41 to move the movable body 32 to 2
It is one of the features that the fully closed state can be maintained with a slight electromagnetic force when the O-rings 35 and 36 are in close contact with each other.

The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the gist of the present invention. For example,
In the example of FIG. 3, the electromagnetic exhaust valve 3 includes two O-rings 3.
Although the pressure receiving portion 37 is formed by 5, 36, another O ring is provided on the outer circumference of the O ring 35, and another pressure receiving portion 37 is formed between the O ring and the O ring 35. It is also possible to provide the O-rings in a triple or quadruple manner, form the pressure receiving portions 37 between the respective O-rings, and provide each of the pressure receiving portions 37 with the exhaust introduction port 38 for introducing the exhaust gas from the cuff 1. Is. According to the configuration, it is possible to receive a stronger pressure from the cuff 1, so that it is possible to cope with a larger cuff 1.

Further, in the configuration of FIG. 1, the diagnostic processing such as blood pressure measurement and waveform analysis is performed by the control computer 55, but the diagnostic processing such as blood pressure measurement and waveform analysis is different from that of the control computer 55. You may make it perform using the computer of. As a result, the control computer 55 mainly needs only to control the inside of the blood pressure measurement signal processing unit 5, so that a microcomputer equipped with an inexpensive CPU having a low processing capacity is sufficient. The measurement signal processing unit 5 itself can be reduced in size and weight, and can be made inexpensive.

Further, as the pressurizing means, other than the pressurizing pump 4, other air pressure sending means may be adopted. In addition to the electromagnetic exhaust valve 3, the exhaust valve may be a motor-driven exhaust valve or an exhaust valve using an electrostrictive element such as a piezoelectric piezo element. Further, the pressure detecting means may be a pressure detecting device other than the pressure sensor 2. As a pressure sensor,
Various types such as a mechanical pressure sensor using a diaphragm and a semiconductor pressure sensor can be used. Further, instead of the coil spring 41 serving as the elastic means, another metal spring such as a disc spring or an elastic member made of rubber or the like may be arranged.

Further, in the blood pressure measurement signal processing section 5, in addition to the control computer 55, each circuit constituting each means is arranged, but a part or all of each circuit is arranged. Instead of providing the storage unit, a storage unit such as a ROM or a RAM may be provided, and a predetermined program may be activated by the control computer 55 and the storage unit, and the program may perform each control described above. Further, the electromagnetic exhaust valve 3 may be connected to another device without being connected to the cuff 1 and used for purposes other than blood pressure measurement. For example, it may be used for controlling the flow rate of gas, controlling the supply device of nitrogen and the like. Furthermore, it may be used to control the supply and discharge of fluids other than gas, such as tap water and alcohol.

[0085]

As described above, according to the present invention, it is possible to create a reference decompression characteristic straight line having an arbitrary inclination intentionally set by a human, and a decompression characteristic along the reference decompression characteristic straight line can be obtained. As a result, it is possible to obtain a blood pressure measurement device corresponding to various cuff sizes and blood pressure measurement targets. In addition, since it becomes easier to reproduce a waveform close to the original waveform of the pulse wave, more detailed information regarding blood pressure values may be obtained, and it is expected that more accurate blood pressure measurement results will be obtained. It

Further, since the electromagnetic exhaust valve of the present invention widens the flow space inside the exhaust valve and allows the exhaust to the outside of the exhaust valve efficiently, the pressure of the fluid such as the incoming air is increased. Even when is low, a large amount of gas can be exhausted by a slight change in the movable body. Further, this electromagnetic exhaust valve has a structure in which, in the fully closed state, the pressure of the incoming gas is received only by the portions surrounded by the O-rings. As a result, even though the entire flange portion of the movable body is large, the area that receives pressure is only a very limited portion, so when in the fully closed state, the fully closed state is maintained with a slight electromagnetic force. The effect that it can be obtained is also obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram illustrating an embodiment of a blood pressure measurement device of the present invention.

FIG. 2 is a diagram illustrating an example of creating a reference decompression characteristic line used in the embodiment of the present invention.

3A and 3B are diagrams illustrating an example of the configuration of an electromagnetic exhaust valve 3 used in the blood pressure measurement device of the present invention, in which FIG. 3A is a side sectional view and FIG. 3B is a sectional view taken along line XX of FIG. FIG.

FIG. 4 is a diagram showing a relationship between a reference pressure reduction characteristic line So generated by a reference pressure reduction characteristic generation circuit 54 and a pulse wave superimposed pressure curve Sw 2 in the cuff 1.

FIG. 5 is a diagram illustrating an example of opening control of an electromagnetic exhaust valve 3 by an electromagnetic exhaust valve control circuit 56.

FIG. 6 is a diagram illustrating an example of solenoid valve control in a conventional blood pressure measurement device.

[Explanation of symbols]

1 cuff 2 Pressure sensor (pressure detection means) 3 Electromagnetic exhaust valve (exhaust valve) 4 Pressurizing pump (pressurizing means) 5 Blood pressure measurement signal processing means 10 Electronic blood pressure monitor (blood pressure measurement device) 31 electromagnetic coil 32 movable body 32a collar part 33 First housing 34 Second housing 35,36 O-ring 37 Pressure receiving part 38 Exhaust inlet 39,40 exhaust port 41 coil spring 51 Pressure amplifier 52 Pulse wave signal processing circuit (pulse wave signal processing means) 53 Pulse wave elimination circuit (pulse wave elimination means) 54 reference decompression characteristic generation circuit (reference decompression characteristic generation means) 55 Control computer 56 Electromagnetic exhaust valve control circuit (exhaust valve control means) 57 Pump drive circuit 58 Display / key operation part

Claims (5)

[Claims] 1. A pressurizing means for pressurizing the cuff, an exhaust valve for reducing the pressure of the cuff on which the pulse wave is superposed after pressurizing by the pressurizing means, and a pressure detecting means for detecting the pressure of the cuff. , A blood pressure measurement signal processing means for measuring a blood pressure value based on a pressure detection signal obtained from the pressure detection means when the exhaust valve operates to reduce the pressure of the cuff on which the pulse wave is superimposed In the measurement device, the blood pressure measurement signal processing means has a certain inclination with respect to a pressure value when the cuff is inflated to a predetermined pressure by the pressurizing means, and linearly reduces the pressure with time. A reference decompression characteristic generating means for generating a reference decompression characteristic straight line, and a pulse wave elimination pressure signal in which the pulse wave component is eliminated or attenuated by eliminating the pulse wave component from the pressure of the cuff on which the pulse wave is superimposed. Pulse wave elimination Means and the reference decompression signal for each time obtained from the reference decompression characteristic line and the difference between the cuff pulse wave component elimination pressure signal at that time, and the cuff pulse wave component elimination than the reference decompression signal When the pressure signal is large, control is performed to increase the opening of the exhaust valve based on the difference, and when the cuff pulse wave component elimination pressure signal is smaller than the reference pressure reduction signal, based on the difference. An exhaust valve control means for performing control to reduce the opening degree of the exhaust valve, and a pulse wave signal processing means for performing signal processing on the pressure of the cuff on which the pulse wave is superimposed to extract a signal necessary for blood pressure measurement, A blood pressure measuring device comprising: 2. The reference decompression characteristic generation means is capable of generating a reference decompression characteristic straight line having an arbitrary inclination, and the magnitude of the inclination can be set according to the heart rate of the blood pressure measurement target. The blood pressure measurement device according to claim 1, which is characterized in that. 3. The pulse wave signal processing means inputs the reference reduced pressure signal from the reference reduced pressure characteristic generating means, and takes a difference from the reference reduced pressure signal from the pressure signal of the cuff on which the pulse wave is superimposed, The blood pressure measurement device according to claim 1 or 2, further comprising pulse wave reproduction processing means for reproducing an approximate original waveform of the pulse wave based on the difference. 4. The exhaust valve is an electromagnetic exhaust valve,
A cylindrical electromagnetic coil and a pressure of air exhausted from the cuff at the tip of the electromagnetic coil that is inserted in the hollow portion of the cylindrical electromagnetic coil and is reciprocally provided along the central axis direction of the electromagnetic coil. A movable body having a disk-shaped collar portion for receiving the elastic body, an elastic body that applies a biasing force to the movable body in a direction opposite to the biasing force applied to the movable body by the electromagnetic coil, and the electromagnetic coil and the movable body. A cylindrical housing for accommodating the elastic body, and at least two different diameters provided concentrically on the inner end surface of the housing on the side facing the flange of the movable body.
A book O-ring, an exhaust introduction port connected to the cuff provided between these O-rings, and an exhaust port provided on at least one of the cylindrical housing side surface and the end surface on the side where the O-ring is provided. The blood pressure measurement device according to claim 1, further comprising: 5. A cylindrical electromagnetic coil and a cylindrical electromagnetic coil which is inserted into the hollow portion of the cylindrical electromagnetic coil so as to reciprocate along the central axis direction of the electromagnetic coil and enters the inside at the tip thereof. A movable body having a disk-shaped brim portion for receiving the pressure of the coming air, an elastic body that applies a biasing force to the movable body in a direction opposite to the biasing force that the electromagnetic coil applies to the movable body, and these electromagnetic bodies. A cylindrical casing for accommodating the coil, the movable body and the elastic body, and at least two O-rings having different diameters which are concentrically provided on the inner end surface of the casing on the side facing the flange portion of the movable body, An exhaust gas inlet provided between these O-rings, and an exhaust port provided on at least one of the side surface of the cylindrical casing surrounding each member and the end surface on the side where the O-ring is provided. Electromagnetic exhaust valve.