JP2557976Y2 - Oscillometric type automatic blood pressure measurement device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oscillometric automatic blood pressure measuring device.

[0002]

2. Description of the Related Art Conventionally, a compression device for compressing an artery in a living body and pressure adjusting means for adjusting the compression pressure of the compression device have been provided, and the compression pressure of the compression device is predetermined. An oscillometric type automatic blood pressure measurement device is provided which measures a blood pressure value such as a systolic blood pressure value based on the amplitude of a pulse wave sequentially obtained in a step of decreasing the compression pressure after the pressure is increased to a target compression pressure. In such an oscillometric automatic blood pressure measurement device, usually, the blood pressure value is determined according to a predetermined blood pressure value determination algorithm, and when the systolic blood pressure value cannot be determined due to insufficient pressure, The blood pressure measurement is performed again after the pressure is increased again to a pressure higher than the target compression pressure by a predetermined amount.

[0003]

However, in the above-mentioned re-pressurization, the predetermined amount to be higher than the target compression pressure is usually a predetermined constant amount. In some cases, the blood pressure was not higher than the person's systolic blood pressure and the blood pressure measurement had to be repeated many times.

The present invention has been made in view of the above circumstances, and a purpose thereof is to measure a blood pressure value based on the amplitude of a pulse wave sequentially obtained in the process of lowering the compression pressure on a living body. In this case, an object of the present invention is to provide an oscillometric type automatic blood pressure measurement device capable of reducing the number of re-measurements when the systolic blood pressure value cannot be determined.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and its gist is to compress an artery in a living body as shown in the claim correspondence diagram of FIG. And a pressure adjusting means for adjusting the compression pressure of the compression device. After the compression pressure of the compression device is increased to a predetermined target compression pressure, the pressure reduction process of the compression pressure is performed. In the oscillometric type automatic blood pressure measurement device of the type that measures the blood pressure value including the systolic blood pressure value based on the amplitude of the pulse wave sequentially obtained, whether or not the determination of the systolic blood pressure value is impossible due to insufficient pressure increase Determination means for determining the systolic blood pressure value, and if the determination means determines that the systolic blood pressure value cannot be determined, systolic blood pressure prediction means for predicting the systolic blood pressure value before performing blood pressure measurement again , Hypertension Oscillometric type than the maximum blood pressure predicted by measuring means and a target compression pressure changing means for changing the target compression pressure so that a predetermined amount higher
An automatic blood pressure measurement device, wherein the systolic blood pressure prediction means is:
The maximum amplitude A among the amplitudes of the pulse waves obtained in the step-down process
_M, the amplitude A _m of the target compression pressure resulting pulse wave, the
Pressing pressure P _M, and when the pulse wave maximum amplitude is obtained
Based on the target compression pressure P _m, the following equation systolic _{P S = P M + A M} (P m -P M) / 2 (A M -A m), in particular to predict the maximal blood pressure P _S is there.

[0006]

According to the oscillometric type automatic blood pressure measuring device having such a configuration, if the determining means determines that the systolic blood pressure value cannot be determined due to insufficient pressure increase, the blood pressure measurement is performed again. By means of systolic blood pressure prediction,
The maximum amplitude A _{M of} the pulse wave amplitudes obtained in the step-down process,
The amplitude of the pulse wave obtained in the target pressing pressure A _m, compression pressure P _M when the pulse wave of the maximum amplitude is obtained, and the target compression pressure P on the basis of _m, systolic blood pressure value from the previous equation P _S Is predicted, and the target compression pressure is changed by the target compression pressure changing means so that the target compression pressure is higher by a predetermined amount than the predicted systolic blood pressure value. Since there is a certain relationship between the amplitude of the pulse wave at the systolic blood pressure value and the amplitude of the pulse wave at the average blood pressure value (maximum amplitude), the amplitude of the pulse wave at the systolic blood pressure value is equal to the maximum amplitude. By using the relationship that is approximately one half of the above, the systolic blood pressure value can be suitably predicted.

[0007]

Accordingly, when it is impossible to determine the systolic blood pressure value due to insufficient pressurization, the systolic blood pressure is obtained in the step of lowering the blood pressure .
With the maximum amplitude A _{M of the} pulse wave amplitude and the target compression pressure
The difference between the amplitudes A _m of the obtained pulse wave (A _M -A _m), Oyo
Beauty, compression pressure P _M when the pulse wave of the maximum amplitude is obtained
And the target compression pressure P _m (P _m -P _M )
Since the systolic blood pressure value is predicted from the previous equation, the target compression pressure
The force becomes an appropriate value, and the compression pressure can be increased more reliably and to the necessary minimum more preferably than the systolic blood pressure value by one re-pressurization, and the number of times of blood pressure remeasurement can be reduced appropriately. .

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 2 is a diagram showing an example of the configuration of the oscillometric type automatic blood pressure measurement device of the present invention. In the figure,
Reference numeral 10 denotes a rubber bag-shaped cuff, which is attached, for example, in a state of being wound around the upper arm 12 of the human body. In cuff 10,
The pressure sensor 14, the switching valve 16, and the air pump 18 are connected via a pipe 20. Switching valve 16
Can be switched between a pressure supply state in which the supply of pressure into the cuff 10 is allowed, a slow discharge state in which the cuff 10 is gradually discharged, and a rapid discharge state in which the cuff 10 is rapidly discharged. Is configured. The pressure sensor 14 is
A pressure signal SP representing the detected pressure is supplied to a static pressure discrimination circuit 22 and a pulse wave discrimination circuit 24, respectively. The static pressure discriminating circuit 22 includes a low-pass filter, discriminates a static pressure component included in the pressure signal SP, and indicates a cuff pressure signal SK representing the static pressure component (hereinafter, referred to as a cuff pressure P).
Is supplied to the control device 28 via the A / D converter 26.
The pulse wave discrimination circuit 24 includes a band pass filter, discriminates a pulse wave component included in the pressure signal SP, and supplies a pulse wave signal SM representing a pulse wave to the control device 28 via the A / D converter 30. I do. This pulse wave is a pressure vibration wave generated from the brachial artery (not shown) and transmitted to the cuff 10 in synchronization with the heartbeat of the subject. In this embodiment, the cuff 10 constitutes a compression device, and the switching valve 16 and the air pump 18 constitute pressure adjusting means.

The control unit 28 includes a CPU, a ROM, an R
The CPU includes a so-called microcomputer having an AM, an I / O port, and the like. The CPU executes signal processing while utilizing a storage function of the RAM in accordance with a program stored in the ROM in advance. A cuff pressure P is adjusted by outputting a drive signal from the I / O port and controlling the switching valve 16 and the air pump 18 via a drive circuit (not shown), and a pulse sequentially obtained in the process of gradually lowering the cuff pressure P. The average blood pressure value, the systolic blood pressure value, and the diastolic blood pressure value are determined based on the amplitude of the pulse wave represented by the wave signal SM, and the determined blood pressure values are displayed on the display device 32. Also, CPU
Determines whether or not the systolic blood pressure value cannot be determined due to insufficient pressure increase in accordance with a program stored in advance in the ROM, and when it is determined that the determination cannot be performed, the pulse obtained in the pressure-lowering process is determined. The maximum amplitude of the wave, the amplitude of the pulse wave at the time of the start of pressure reduction, the cuff pressure P when the pulse wave of the maximum amplitude was obtained, and predicting the systolic blood pressure value based on the cuff pressure P at the time of the start of pressure reduction, After re-boosting to a target cuff pressure higher by a predetermined amount than the predicted systolic blood pressure value, blood pressure measurement is executed again.

Next, the operation of the oscillometric type automatic blood pressure measuring device having the above-mentioned configuration will be described with reference to the flowchart of FIG.

When the power is turned on and an initial process (not shown) is executed and a start push button switch (not shown) is turned on, step S1 is executed, the switching valve 16 is switched to the pressure supply state, and the air pump 18 is turned on. When actuated, the cuff pressure P is set to a predetermined constant target cuff pressure P.
_m (for example, a pressure of about 180 mmHg).
Next, in step S2, the operation of the air pump 18 is stopped, and the switching valve 16 is switched to the slow exhaust pressure state, whereby the slow reduction of the cuff pressure P is started.

In the following step S3, it is determined whether the pulse wave signal SM has been read and one pulse wave has been detected.
If this determination is denied, step S3 is repeatedly executed. If the determination is affirmed, the subsequent blood pressure value determination routine of step S4 is executed. In this blood pressure value determination routine, the amplitude of the pulse wave detected in step S3 is obtained and stored, and a well-known oscillometric blood pressure value determination algorithm is executed, for example, to reduce the blood pressure in the blood pressure reduction process. Is determined as the mean blood pressure value (MEAN) at the time when the pulse wave of the maximum amplitude is obtained at the point where the difference value of the pulse wave amplitude on the high pressure side becomes higher than the mean blood pressure value (pulse). The systolic blood pressure value (SYS) is determined based on the cuff pressure P at the inflection point of the wave amplitude change curve), the average blood pressure value, and the like, and a pulse wave on a lower pressure side than the average blood pressure value when the blood pressure is further reduced. The diastolic blood pressure value (DIA) is determined based on the cuff pressure P at the point where the amplitude difference value becomes the maximum (the inflection point of the pulse wave amplitude change curve).

Next, in step S5, it is determined whether or not the blood pressure measurement has been completed. If the blood pressure measurement has not been completed yet, step S6 is executed, and it is determined whether the systolic blood pressure value cannot be determined due to insufficient pressure increase.
The determination as to whether or not the determination of the systolic blood pressure value is impossible can be made, for example, even if a step (not shown) for determining the systolic blood pressure value is executed in the blood pressure value determining routine. The determination is performed based on whether the systolic blood pressure value cannot be determined due to the lack of the wave amplitude data. In other words, the determination is performed based on whether or not there is an inflection point of the pulse wave amplitude change curve on the high pressure side of the average blood pressure value. As described above, in the blood pressure value determination algorithm of the present embodiment, the systolic blood pressure value is determined based on the maximum value of the difference between the pulse wave amplitudes on the high pressure side from the average blood pressure value. Even when the average blood pressure value is not determined, the determination in step S6 as to whether the systolic blood pressure value cannot be determined is made before the average blood pressure value is determined. In the present embodiment, the above-described step S6, more precisely, the control device 2
The portion used to execute step S6 among the CPU, ROM, RAM and the like of No. 8 corresponds to the determination means.

If the determination in step S6 is negative, steps S3 to S6 are repeatedly executed. At this time, if all the blood pressure values are measured and the judgment in step S5 is affirmative, step S7 is executed and the switching valve 16 is switched to the rapid exhaust pressure state, whereby the pressure in the cuff 10 is quickly exhausted. At the same time, step S8 is executed, and the measured blood pressure value is displayed on the display 32. On the other hand, if the determination in step S6 is affirmative, that is, if the systolic blood pressure value cannot be determined due to insufficient blood pressure, the re-boost target determination shown in FIG. The routine is executed.

In the above-described routine for determining the target of re-boost,
First is the step SS1 is executed, the amplitude difference K ₁ (A by subtracting the amplitude A _m of the pulse wave at a maximum amplitude A _M from the step-down start or target cuff pressure P _m of the pulse wave of the step-down process
_M -A _m: with reference to FIG. 5) is calculated, the pressure difference K ₂ by subtracting the cuff pressure P _M corresponding to the average blood pressure value from a target cuff pressure P _m (P _m -P _M: see Figure 5) Is calculated. Next, is step SS2 is executed, whether the amplitude difference K ₁ is zero or less is determined. Amplitude difference K ₁
There is that it is below zero (zero in practice), but the target cuff pressure P _m is mean blood pressure (= P _M) the maximum amplitude A _M A is lower than corresponds to the mean blood pressure value The fact that the amplitude difference K ₁ is positive means that the target cuff pressure P _m is higher than the average blood pressure value (= P _M ) and the maximum amplitude A _M , for example, as shown in FIG. Corresponds to the average blood pressure value.

[0017] If the determination in step SS2 is negative, i.e., if the amplitude difference K ₁ is positive, the cuff pressure P _S corresponding thereto i.e. systolic blood pressure value is predicted by step SS3 is executed. Prediction of the cuff pressure P _S corresponding to the systolic blood pressure, as shown in FIG. 5, the cuff pressure P _M corresponding to the average blood pressure value, a target cuff pressure P _m, the maximum amplitude A _M in cuff pressure P _M, and based on the amplitude a _m of the target cuff pressure P _m, by utilizing the relationship of the amplitude a _S of the pulse wave at the systolic blood pressure value is the maximum amplitude a substantially one half of the _M in the mean blood pressure Done. That is, in FIG. 5, the amplitude value A _M / 2 on a straight line 1 indicated by a dashed line passing through the points a and b.
When cuff pressure P _S corresponding to the assumption that correspond to systolic blood pressure value is the cuff pressure P _S corresponding to the systolic blood pressure value is determined from the relationship of Equation 1 based on the similarity between the triangle abc and a triangle ade according to equation 2 . Also, Equation 3 is an equation
2 shows K ₁ and K ₂ in detail. In this embodiment, the part used for executing step SS3 of the CPU, ROM, RAM and the like of the controller 28 corresponds to the systolic blood pressure predicting means.

[0018]

K ₁ : K ₂ = A _M / 2: (P _S −P _M )

[0019]

## EQU2 ## P _S = P _M + A _M K ₂ / 2K ₁

(Equation 3) P _S = P _M + A _M (P _m −P _M ) / 2 (A _M -A _m )

Next, at step SS4, the target cuff pressure P
_m is, the cuff pressure P _S corresponding to the predicted systolic blood pressure
To a value obtained by adding a predetermined constant value C ₁ (for example, a value of about 15 mmHg). In the present embodiment, in step SS4, more precisely, the CP
A portion used for executing step SS4 among U, ROM, RAM and the like corresponds to a target compression pressure changing unit.

Meanwhile, if the determination in step SS2 is affirmative, that is, the amplitude difference K ₁ is the case where zero or less, it is impossible to predict the systolic blood pressure value determined by using Equation 2, step SS5 There are running, the target cuff pressure P _m is changed to a constant value C ₂ (for example, a value of about 65 mmHg) higher by a predetermined value than the target cuff pressure P _m when the boosting insufficient.

[0022] When the target cuff pressure P _m for this way re-boosting is determined, after being raised to the determined target cuff pressure P _m is executed step S1 again, slow decreasing Will be measured again.

As described above, according to the present embodiment, step S
If it is determined that the target cuff pressure _Pm is low and thus the systolic blood pressure value cannot be determined in Step 6, the maximum amplitude A _M among the amplitudes of the pulse waves obtained in the blood pressure lowering process is determined in Step SS3. target cuff pressure P amplitude of the pulse wave obtained in _m a _m, the cuff pressure P _M when the pulse wave of the maximum amplitude is obtained, and systolic blood pressure value from the equation 2 on the basis of the target cuff pressure P _m (= P _s ) is predicted, and in step SS4, the target cuff pressure P _m is changed so as to be higher than the predicted systolic blood pressure value (= P _s ) by a predetermined amount. Therefore, the cuff pressure P can be more reliably set to be higher than the systolic blood pressure value by one re-pressurization, and when the systolic blood pressure value cannot be determined, the cuff pressure is higher than the target cuff pressure by a predetermined fixed amount. The number of re-measurements of the blood pressure can be reduced as compared with the conventional case where the pressure is re-pressurized to the pressure.

Further, according to this embodiment, the systolic blood pressure value is preferably predicted by utilizing the relationship that the amplitude of the pulse wave at the systolic blood pressure value is approximately one half of the maximum amplitude at the average blood pressure value. it is possible to, since the constant value C ₁ added to the target cuff pressure P _m when the boost insufficient in determining the target cuff pressure P _m for re boosting may not be so large, the There is an advantage that the burden due to pressure on the measurer is not unnecessarily increased.

While the embodiment of the present invention has been described with reference to the drawings, the present invention is applicable to other embodiments.

[0026]

For example , in the above embodiment, each time a pulse wave is detected, a blood pressure value determination routine is executed to sequentially determine an average blood pressure value, a systolic blood pressure value, and a diastolic blood pressure value. It is configured so that when the systolic blood pressure value cannot be determined during the lowering of blood pressure, the blood pressure is raised again,
For example, after blood pressure reduction is completed, each blood pressure value is determined based on the pulse wave sequentially obtained in the blood pressure lowering process, and when the systolic blood pressure value cannot be determined, the pressure is raised again. May be done.

In the above-described embodiment, whether the systolic blood pressure value cannot be determined due to insufficient pressure rise or not is determined in step S6 because the inflection of the pulse wave amplitude change curve is higher than the average blood pressure value. This is performed based on whether or not a point exists, but this is not always necessary. For example, a predetermined constant value is determined after the execution of the step for determining the systolic blood pressure value in the blood pressure value determination routine is started. The determination may be performed based on whether the systolic blood pressure value is not determined even after the elapse of time.

In addition, the present invention can be variously modified without departing from the gist thereof.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims.

FIG. 2 is a block diagram showing a configuration of an oscillometric type automatic blood pressure measurement device to which the present invention is applied.

FIG. 3 is a flowchart for explaining the operation of the apparatus of FIG. 2;

FIG. 4 is a flowchart for explaining a re-boost target determination routine of the flowchart of FIG. 3;

5 is a systolic blood pressure value (= step SS3 in FIG. 4).
It is a figure for explaining the method of estimating _PS ).

[Explanation of symbols]

 10: Cuff (compression device) ｛16: Switching valve, 18: Air pump｝ Pressure adjustment means Step S6: Judgment means Step SS3: Systolic blood pressure prediction means Step SS4: Target compression pressure change means

Claims (1)

(57) [Scope of request for utility model registration] 1. A compression device for compressing an artery in a living body, and pressure adjusting means for adjusting a compression pressure of the compression device, wherein a compression pressure of the compression device is set to a predetermined target compression pressure. In an oscillometric type automatic blood pressure measurement device of the type in which a blood pressure value including a systolic blood pressure value is measured based on the amplitude of a pulse wave sequentially obtained in the process of lowering the compression pressure, Determining means for determining whether the determination of the hypertension value is impossible; and determining that the determination of the systolic blood pressure value is impossible by the determining means, the systolic blood pressure value is determined prior to performing the blood pressure measurement again. Oh with the highest blood pressure predicting means for predicting, the target compression pressure changing means for changing the target compression pressure to be higher a predetermined amount than the predicted systolic blood pressure by outermost hypertension predicting means
A symetric automatic blood pressure measurement device, wherein the systolic blood pressure predicting means includes a pulse wave obtained in the step of lowering blood pressure.
The maximum amplitude A _{M of} the amplitudes obtained from the target compression pressure
The pulse wave amplitude A _m, when the pulse wave of said maximum amplitude is obtained
Based compression pressure P _M, and the target compression pressure P _m
Te, oscillation, characterized in that the following equation systolic _{P S = P M + A M} (P m -P M) / 2 (A M -A m), to predict the maximal blood pressure P _S
Lometric type automatic blood pressure measurement device.