JPS63171538A - Automatic blood pressure measuring apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to improvements in automatic blood pressure measuring devices.

Conventional technology and its problems In general, when measuring blood pressure, a cuff is wrapped around a part of the living body and compressed to generate pulse-synchronized waves (pulse waves), which are pressure vibration waves that are generated in synchronization with the living body's pulse. There has been provided an automatic blood pressure measurement device that detects the pulse synchronous wave and automatically determines the blood pressure value based on the change in the pulse synchronized wave. In such a device, if the detected pulse synchronized wave is determined to be noise generated due to movement of the living body, rubbing of the cuff, or pulsation of a pump that supplies pressure to the cuff, etc., the pulse synchronized wave is detected. By removing the pulse synchronous wave from the input data, noise is prevented from being mixed into the normal pulse synchronous wave.

However, when noise is removed from input data as described above, the information on the pulse synchronous wave at the time when the noise occurs is lost from the input data, so the determination is made based on the pulse synchronous wave in such input data. There was a problem in that blood pressure values were not sufficiently reliable.

Means for Solving the Problems The present invention was made against the background of the above-mentioned circumstances, and its gist is to apply compression pressure from a cuff wrapped around a part of a living body at a predetermined speed. It includes a cuff pressure adjustment means that continuously changes it, and a pulse synchronized wave detection means that detects a pulse synchronized wave generated during changes in the cuff compression pressure, and determines the blood pressure value based on the change in the pulse synchronized wave. (b) noise determination means for determining that the pulse synchronous wave detected by the pulse synchronous wave detection means is noise; and (b) false detection means for detecting the pulse synchronous wave by the noise determination means. When it is determined that the pulse synchronized wave detected by the means is noise, the cuff pressure adjusting means partially returns the compression pressure of the cuff to the pressure before the noise generation, and then changes it again at the predetermined speed. a control means for causing
It is to include.

Operation and Effect of the Invention With this arrangement, as shown in the claim correspondence diagram of FIG. If the noise determination means determines that the noise is noise, the control means causes the cuff pressure adjustment means to return the compression pressure of the cuff to the pressure before the occurrence of the noise, and then changes the cuff pressure again.

Therefore, according to the present invention, the pulse-synchronized wave corresponding to the time when the noise occurred is detected again, which is different from the conventional method in which blood pressure values were measured without information about the pulse-synchronized wave at the time when the noise occurred. Compared to other devices, the reliability of blood pressure measurement results can be improved.

EXAMPLE Below, one example of the present invention will be described in detail based on the drawings.

FIG. 2 explains the configuration of the automatic blood pressure measuring device of this embodiment. In the figure, a pressure sensor is attached to a rubber bag-shaped cuff 10 that is wrapped around the upper arm of a living body and presses it. 12, the throttle 14, and the vane pump 16 are connected to the piping 20.
are connected to each other via. The pressure sensor 12 detects the pressure within the cuff 10 and supplies a pressure signal sp to the cuff pressure detection circuit 22 and the pulse wave detection circuit 24.

The cuff pressure detection circuit 22 includes a low-pass filter for distinguishing the static pressure (cuff pressure) in the cuff 0 from the pressure signal SP, and A/D converts the cuff pressure signal SPc representing the cuff pressure P in the cuff 10. It is supplied to the CPU 28 via the device 26. The pulse wave detection circuit 24 detects the dynamic pressure within the cuff 10 from the pressure signal sp.
That is, it is equipped with a band-pass filter for discriminating a pulse-synchronized wave (pulse wave), which is a pressure vibration component generated in synchronization with the pulse, and a pulse wave signal SP0 representing the pressure vibration is transmitted via the A/D converter 30. Supply to CPO2B. That is, the pressure sensor 12 and the pulse wave detection circuit 24 function as pulse synchronous wave detection means of this embodiment.

Further, the throttle 14 is used to constantly discharge the gas in the pipe 20 in small amounts toward the atmosphere.

The CPU 28 uses the storage function of the RAM 34 to
The input signal is processed according to a program stored in advance in the M32, and a drive signal is output to the vane pump 16 via the output interface 36, and the blood pressure value is displayed on the blood pressure display 38. ' The vane pump 16 is shown in FIGS. 3 and 4 (FIG. 3 IV).
- IV view).

An insertion hole 41 having a relatively large diameter and a circular cross section that penetrates the center of the prismatic housing 40 has a cylindrical hole having the same axial length as the housing 40 and a smaller diameter than the insertion hole 41. The rotor 42 is inserted eccentrically by a predetermined amount downward from the axis of the housing 40 in FIGS. 3 and 4. Further, plate-shaped end plates 44 and 46 are respectively assembled using bolts or the like so as to close the left and right openings of the housing 40 in FIG. A plate member 49 having a through hole 47 is assembled on the side surface. A through hole 48 is passed through the center of the rotor 42 in the axial direction, and a rotating shaft 50 is fitted into the through hole 48 so as not to be relatively rotatable.
Both ends of the rotating shaft 50 are connected to end plates 44 and 46.
They are respectively supported for relative rotation by bearings 52 and 54 within. Then, a small diameter portion 56 formed in a portion protruding from the end plate 46 at one end of the rotating shaft 50 passes through the through hole 47 of the plate member 49 and is connected to the DC electric motor 60 by the coupling member 58. The rotational force of the DC electric motor 60 is transmitted to the rotor 42 by being connected to the drive shaft 62 so as not to be relatively rotatable.

The rotor 42 has four elongated grooves 64 extending radially from the outer circumferential surface thereof and spaced equally apart along the axial direction.
are formed in these grooves 64, and the longitudinal dimension thereof is the same as the axial dimension of the rotor 42, and the dimension in the direction perpendicular to the longitudinal direction is slightly smaller than the depth dimension of the groove 64. Four thin rectangular vanes 66 that are smaller
a, 66b, 66c, and 66d are each fitted so as to be movable relative to the groove 64 in the radial direction. Those vanes 66a, 66b, 66c, 66d are springs 65
are biased toward the outer circumferential side by the rotor 42, and are always in contact with the inner circumferential surface of the housing 40 and can slide relative thereto as the rotor 42 rotates. In other words, from a state where the vane 66d located at the lowest position in FIG. The four vanes 66a to 66d protrude until they come into contact with the inner peripheral surface of the housing 40.
The volume of the space 67 between the rotor 42 and the housing 40, which are divided into two, changes in accordance with the rotation of the rotor 42.

On one side of the end plate 44 that is not assembled to the rotor 42, there is a gas inlet 68 that allows the atmosphere to flow into the space 67, and a gas inlet 68 that is connected to the piping 20 and that connects the gas to the cuff 1.
The lower gas outflow lowers 0 for causing gas to flow out into the air are protruded and opened, and are passed through the end plate 44. A part of the gas inlet 68 is opened at the left side of the space 67 in FIG. 4, and a part of the gas outflow lower 0 is opened at the lower right part of the space 67 in the figure. When is rotated clockwise as shown by the arrow in the figure, the volume of gas supplied from the gas inlet 68 into the space 67 between the vanes 66d and 66a and between the vanes 66a and 66b increases. After being expanded to the maximum, the gas decreases toward the opening of the gas outflow lower 0, and the gradually compressed gas flows from the gas outflow lower 0 to the piping 20.
It is designed so that it can be leaked to. Therefore, in the vane pump 16 configured as described above, since the gas is gradually compressed and discharged, the pulsation and noise that occur when pumping gas are reduced compared to other devices such as electric pumps. significantly reduced.

Here, in the vane pump 16, the rotor 42, the vanes 66a to 66d, and the end play) 44.46
A small gap is formed between the two, and air is exhausted through the gap, so that a discharge pressure corresponding to the rotational speed of the drive motor 60 can be obtained. Furthermore, since the gas in the cuff 10 is always exhausted from the aperture 14, albeit in small amounts, the rotational speed of the rotor 42 is increased to supply gas in an amount exceeding the amount of gas exhausted from the aperture 14 into the cuff 10. By doing so, the pressure inside Cafe 0 is increased. Therefore, the vane pump 16 and the throttle 14 function as cuff pressure adjusting means in this embodiment. Note that grooves 72 and 74 are formed along the space 67 at the openings of the gas inflow port 68 and the gas outflow lower 0 and their peripheries on one surface of the end plate 44 on the rotor 42 side.

The operation of this embodiment configured as above will be explained based on the flowchart of FIG.

First, when the power (not shown) is turned on, the start push button 76 is pressed in step S1 and a start signal is sent to the CPU.
2 is supplied to B, and it is determined that the following step S
2 is executed, and as shown in FIGS. 6(b) and 6(c), the vane pump 16 is operated at the maximum rotation speed, and the pressure inside the cuff 10 is rapidly increased.

In step S3, the pressure P inside the cuff 10 is determined.

A target cuff pressure P that is predetermined so that it is sufficiently lower than the diastolic blood pressure value of the living body. It is determined whether or not it has been reached. If it is determined that the distance has not been reached, the determination in step S3 is repeated, but if it is determined that the distance has been reached, the subsequent step S4 is executed.

In step S4, the rotation speed of the vane pump 16 is rapidly decreased from its maximum rotation speed so that the cuff pressure Pc is increased at a speed suitable for pulse wave detection, for example, at a speed of about 3 mmHg/sec. The rotational speed is gradually increased at a predetermined rate of increase, and in the process of increasing the pressure of the cuff 10, the pulse waves shown in FIG. 6(a) are sequentially read each time they are detected.

The pulse wave read in step S4 is
In step 5, it is determined whether or not the noise is caused by movement of the living body, cuff rubbing, etc., based on predetermined criteria. That is, if the read pulse wave exceeds the maximum value of a biological pulse wave, it is determined to be noise. If it is determined that the read pulse wave is normal, the blood pressure value determination routine in the subsequent step S6 is executed, but since the pulse wave is not read sufficiently at the beginning, the measurement is completed in step S7. It is determined that the process has not been performed, and the operations from step 84 onwards are repeated. Therefore, in this embodiment, step S5 corresponds to the noise determination means.

However, in step S4, if the pulse wave A shown by the dashed line in FIG. It is determined that it is noise, and in step S8, the abnormally large pulse wave is removed from the input data, and the cuff 1 at the time when the noise occurred is removed.
The value of the cuff pressure PcA at the time of abnormality occurrence, which is a pressure of 0, is read.

Subsequently, step S9 is executed, and the rotational speed of the vane pump 16 is rapidly reduced to the cuff pressure P.

is lowered, and in step SIO,
Has the actual cuff pressure P been lowered to a pressure (Pea-α) lower by a predetermined value α than the cuff pressure a predetermined time before the abnormal cuff pressure PcA, that is, the abnormal cuff pressure PCA? It is determined whether or not. Cuff pressure P is (Pc
While it is determined that the pressure has not been reduced to A-α), steps S9 and S10 are repeatedly executed,
If it is determined that the pressure has been lowered, the operations from step 84 onwards are executed again. That is, in the process where the cuff pressure P is increased again at a predetermined speed, the pulse wave that occurs until the abnormal cuff pressure pca is reached and the pulse wave B that should be detected at the time when the pressure of the cuff 10 is PcA are as follows. The blood pressure value is determined based on the pulse wave B, etc., which is read in step S4 instead of the noise. Therefore, in this embodiment, step S9 and step S10 correspond to the control means. By repeating the above-described operations, the result shown in FIG.
Diastolic blood pressure value based on the detected pulse wave as shown in l.
When the average blood pressure value and the systolic blood pressure value are determined, the determination in step S7 is affirmed and the subsequent step 311 is executed, and the operation of the vane pump 16 is stopped or reversed to rapidly evacuate the inside of the cafe 0. The determined blood pressure value is displayed on the blood pressure display 38.

As described above, in this embodiment, when determining the blood pressure value based on the pulse wave detected during the pressurization process of the cuff 10, if noise generated due to the movement of the living body is detected, is the cuff pressure P from the time the noise is detected.
By lowering c by a predetermined value α and increasing the pressure again at a predetermined speed, a pulse wave corresponding to the cuff pressure Pc-b at the time when the noise occurred, that is, the abnormal cuff pressure pca, is detected and read in place of the noise. It will be done. therefore,
According to this embodiment, the reliability of the determined blood pressure value is significantly improved compared to the conventional device that determines the blood pressure value without pulse wave information corresponding to the time when noise occurs. Effects can be obtained.

In addition, in this embodiment, since the vane pump 16 is used as the cuff pressure adjustment means, the pulsation and noise transmitted from the vane pump 16 are reduced compared to conventional means such as an electric pump, and it is also economical. will improve.

Further, since the vane pump 16 discharges gas from the gas inlet 68 to the atmosphere by stopping or reversing its rotation, it is necessary to provide a special exhaust means such as an exhaust valve to discharge the gas from the cuff 10. There is no.

Furthermore, the vane pump 16 has four
Gas is supplied into the cuff 10 by rotating the vanes 66a to 66d, and since the inertia during rotation is relatively small, the responsiveness to six commands such as stopping or starting operation is said to be high. Benefits can be obtained. Note that the pulsation transmitted from the vane pump 16 is about 600 Hz/sec, and even if such pulsation mixes with the pulse wave, which is about 0°5 to 10 Hz/see, for example, the pulse wave detection circuit 24 is not equipped. The pulse wave can be sufficiently distinguished from the pulse wave by a band-pass filter.

In the above-described embodiment, the blood pressure value is determined during the pressure increasing process of the cuff 10, but the blood pressure value may be determined during the rate-limiting pressure decreasing process of the cuff 10. In this case, when noise occurs,
The abnormal cuff pressure PeA is increased by a predetermined value α at a predetermined rate.

Further, since the throttle 14 increases the rotational speed of the vane pump 16 over the entire range, it may be removed if the pulsation of the discharge pressure does not pose much of a problem.

The above-mentioned embodiment is merely one embodiment of the present invention, and various modifications may be made to the present invention without departing from the spirit thereof.

[Brief explanation of the drawing]

FIG. 1 is a diagram corresponding to claims of the present invention. FIG. 2 is a block diagram showing the configuration of essential parts of an automatic blood pressure measuring device that is an embodiment of the present invention. FIG. 3 is a partial sectional view of the vane pump of FIG. 2 viewed from the side. Figure 4 is the same as Figure 3.
It is a figure seen from the V-IV line. FIG. 5 is a flowchart illustrating the operation of the automatic blood pressure measuring device of FIG. 2. Figures 6(a) and (b). and (C1 are time charts showing changes in pulse wave, cuff pressure, and vane pump rotation speed, respectively. 10: Cuff

Claims (2)

[Claims] (1) A cuff pressure adjustment means that continuously changes the compression pressure of a cuff wrapped around a part of a living body at a predetermined speed, and a pulse rate that detects a pulse synchronized wave generated during changes in the compression pressure of the cuff. synchronous wave detection means, and determines a blood pressure value based on a change in the pulse synchronous wave, the automatic blood pressure measuring device is configured to determine that the pulse synchronous wave detected by the pulse synchronous wave detection means is noise. and a noise determining means for causing the compression pressure of the cuff to generate noise in the cuff pressure adjusting means when the noise determining means determines that the pulse synchronous wave detected by the pulse synchronous wave detecting means is noise. An automatic blood pressure measuring device comprising: control means for returning the pressure to the previous pressure and then changing it again at the predetermined speed. (2) The cuff pressure adjusting means includes a vane pump, and the control means controls the compression pressure of the cuff by changing the rotational speed of the vane pump. Automatic blood pressure measuring device as described.