JP2936815B2 - Electronic sphygmomanometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic blood pressure monitor,
More specifically, the present invention relates to an electronic sphygmomanometer capable of appropriately setting a pressurization stop point.

[0002]

2. Description of the Related Art In an electronic sphygmomanometer, for example, the cuff pressure is changed over time (see FIG. 5A), and the amplitude of a pulse wave superimposed on this cuff pressure is changed (FIG. 5B). ) To calculate the blood pressure. FIG. 5B shows a change in the pulse wave amplitude in the process of reducing the cuff pressure of the oscillometric sphygmomanometer, and point P indicates the maximum amplitude point ( _AMAX ). Point D is a point having an amplitude of 0.7 A _MAX with respect to the maximum amplitude point, and point S is a point having an amplitude of 0.5 A _MAX with respect to the maximum amplitude point. Then, for example, from each point of FIG. 5A corresponding to the points S and D, the systolic blood pressure (systolic blood pressure) and the diastolic blood pressure (diastolic blood pressure) are obtained.
Was decided.

In this type of electronic sphygmomanometer, since the blood pressure value is determined as described above, the cuff is pressurized in advance until the point S in FIG. Needs to be decompressed. In such a case, there is a problem in which value the cuff pressurization is stopped, but conventionally, for example, in the process of pressurizing the cuff pressure, the systolic blood pressure value is conveniently estimated and the pressurization setting is set based on the estimated value. The pressurizing stop point is determined based on the pressure setting value.

An example of a convenient method of estimating the systolic blood pressure value will be described. From the transition of the pulse wave amplitude in the pressurization process, 0.5 A to the maximum value (A _MAX ) of the pulse wave amplitude is obtained.
The point of the _MAX pulse wave amplitude was specified, and the cuff pressure corresponding to that point was estimated as the systolic blood pressure value for convenience (see the right side of FIG. 4).

[0005]

However, for example, in the case of a subject having a very thin arm, the rate of applying the cuff pressure becomes too high, and a pulse wave rate sufficient to estimate the systolic blood pressure value is acquired. It may not be possible (see the left side of FIG. 4). The diagram on the left side of FIG. 4 illustrates a case where the pressurization speed is too fast, and is an example in which only two pulse waves could be captured because the pressurization was too fast. In such a case, the systolic blood pressure value cannot be estimated, so that the pressurization stop point cannot be set appropriately, and therefore, there is a risk that the subject may be disturbed by continuing to pressurize unnecessarily. . In addition, since the pressurization stop point cannot be set to an appropriate value, the decompression process is started from an inappropriate point, and in some cases, the blood pressure measurement fails due to insufficient pressurization.

The present invention has been made in view of such a problem, and when the estimation of the systolic blood pressure fails in the pressurizing process, the cuff pressure is immediately decreased immediately, and thereafter, the systolic blood pressure is reduced. It is an object of the present invention to provide a blood pressure shape for calculating a next pressurization condition based on an operation parameter or the like when estimation fails.

[0007]

In order to achieve the above object, an electronic sphygmomanometer according to claim 1 comprises a cuff for compressing a living artery, a pressurizing means for pressurizing the cuff, and a pressure in the cuff. A pressure sensor for detecting, a pulse wave extracting means for extracting a pulse wave signal superimposed on the cuff pressure signal from the cuff pressure signal detected by the pressure sensor, and an amplitude value of the pulse wave signal extracted by the pulse wave extracting means. Pulse wave amplitude calculating means for calculating, pressure stop point calculating means for calculating a pressurizing stop point of the cuff pressure based on a temporal transition of the pulse wave amplitude calculated by the pulse wave amplitude calculating means, A pressurizing stop means for stopping the operation of the pressurizing means when the cuff pressure reaches the stop point; a depressurizing means for gradually reducing the cuff pressure after the pressurization is stopped; and determining the blood pressure value in the process of reducing the cuff pressure. Electronic sphygmomanometer equipped with Operating state storage means for storing an operation parameter for determining an operation state of the pressurizing means in the pressurizing step; pulse wave number storing means for storing the number of vibrations of the pulse wave extracted in the pressurizing step; When the stop point calculation means cannot calculate the pressurization stop point, the cuff pressure rapid drop means for rapidly lowering the cuff pressure, and when the pressurization stop point cannot be calculated, the pulse wave number storage means stores the cuff pressure. Operating condition correcting means for correcting some or all of the values of the operating parameters from a predetermined relational expression based on the number of vibrations of the pulse wave and the operating parameters; and operating the pressurizing means under the corrected operating conditions. And a re-drive means for causing the re-drive.

Further, in the electronic blood pressure type according to the second aspect,
The operation parameter stored in the operation state storage unit according to claim 1 is selected from a cuff pressure application speed, a voltage value applied to the application unit, and a pulse width of a pulse wave supplied to the application unit. , Or any combination thereof. Further, the electronic blood pressure type according to the third aspect is characterized in that the operating parameter corrected by the operating condition correcting means in the first aspect is a pulse width of a pulse wave supplied to the pressurizing means.

[0009]

The operating state storing means stores operating parameters for determining the operating state of the pressurizing means in the pressurizing process. Although the operation parameters are not particularly limited, in the blood pressure type according to claim 2, the pressure rate of the cuff pressure, the voltage value applied to the pressure means, the pulse width of the pulse wave supplied to the pressure means,
Is limited to any one selected from the above, or any combination.

[0010] The pulse wave number storage means stores the number of vibrations of the pulse wave extracted in the pressurization process. Further, the cuff pressure drop unit rapidly drops the cuff pressure when the pressurization stop point cannot be calculated because the pressurization speed is too high in the pressurization process. The operating condition correcting means corrects a part or all of the operating parameters from a predetermined relational expression based on the number of pulse wave vibrations and the operating parameters when the pressurization stop point cannot be calculated. Then, the re-drive means operates the pressurizing means under the corrected operating condition. The operation parameter to be corrected is not particularly limited, but in the blood pressure type according to the third aspect, only the pulse width of the pulse wave supplied to the pressurizing means is corrected.

[0011]

1 is a block diagram of an electronic sphygmomanometer according to an embodiment of the present invention. This electronic sphygmomanometer includes a cuff 1 for compressing a living artery by air pressure, a pump 2 for supplying air to the cuff 1, a quick exhaust valve 3 for rapidly exhausting the pressure (air pressure) of the cuff 1, and an air for the cuff 1 A slow exhaust valve 4 for gradually exhausting the gas, a pressure sensor 5 for detecting the pressure of the cuff 1, a low-pass filter 6, an A / D converter 7 for converting the output of the pressure sensor 5 into a digital value, and an A / D An MPU 8 which takes in a signal from the converter 7 and performs various processes described later;
An indicator 9 for displaying the measured blood pressure value is provided.

FIG. 2 is a flowchart showing the entire operation of the electronic sphygmomanometer shown in FIG. In this embodiment, the pump application voltage E _P , the pulse width W _P of the pulse supplied to the pump, the cuff pressurization speed S _I (the above is the operation parameter of the pump 2), and the extraction in the pressurization process shows an example of modifying the value of the pulse width W _P based on the number of vibrations N _P of the pulse wave. Hereinafter, the operation of the electronic sphygmomanometer will be described with reference to FIG.

When the operation is started by a start switch or the like, the MPU 8 drives the pump 2 according to the initial conditions to start pressurization (step ST (hereinafter abbreviated as ST)).
1). Next, the MPU 8 inputs necessary data and temporarily sets the pressurizing condition suitable for the subject (ST).
2). The MPU 8 pressurizes the cuff 1 under the pressurizing condition, and stores the pump applied voltage E _P0 and the pulse width W _P0 of the pulse supplied to the pump in this state (ST3). This is the data needed to correct the pressurization conditions later if the systolic blood pressure could not be estimated in the pressurization process because the pressurization conditions that were just set did not match the subject. is there.

Next, the MPU 8 detects the cuff pressure value from the pressure sensor 5, calculates the pressurizing speed S _I0 from the change in the cuff pressure value, and stores it (ST4). This pressing speed S
_{I0 is} also data used when it is necessary to correct the current pressurization condition. When the above process is completed, a pressurizing process is performed (ST5). Specifically, MPU8
The cuff pressure is sequentially input from the pressure sensor 5, and a pulse wave signal is extracted therefrom (pulse wave extracting means). By tracking the pulse wave vibration, the amplitude value of each pulse wave vibration is calculated one after another (pulse wave amplitude calculating means). Next, consider the time course of the amplitude value of the thus pulse wave that is calculated to detect a pulse wave having an amplitude of 0.5A _MAX example for the amplitude maximum value A _MAX, corresponding to the pulse wave The estimated cuff pressure is temporarily estimated as the systolic blood pressure value. Then, the pressurization stop point is determined based on the systolic blood pressure value. However, if the pressurization condition is inappropriate for the subject, the number of pulse wave oscillations may be too small to estimate the systolic blood pressure value.

Therefore, in ST6, it is determined whether or not the systolic blood pressure value can be estimated in the pressurizing process (ST5) (ST6). If the systolic blood pressure value can be estimated, pressurization is stopped at the pressurization stop point determined by the value (S
T11) Thereafter, the process enters the decompression process to determine the blood pressure value (S11).
T12). Then, the blood pressure value is displayed on the display 9 (ST
13) The cuff is quickly evacuated and the measurement is terminated (ST1).
4).

On the other hand, if the systolic blood pressure value cannot be estimated, the processing after ST7 is performed. That is, MPU8
The number of pulse wave oscillations N _P0 calculated in the pressurization process (ST5) is stored (ST7). Note that the smaller the number N _P0 of the pulse wave vibrations, the more inappropriate the setting of the pulse width of the pulse supplied to the pump 2. Since it has become clear that proper blood pressure measurement cannot be performed under the pressurizing condition of this time, the MPU 8 operates the quick exhaust valve 3 to rapidly reduce the cuff pressure (ST8). Therefore, even if the pressurizing condition is inappropriate, there is no fear that the subject is given unnecessary pain. Subsequently, MPU 8 applied voltage E _P0 has been stored in ST3, the pulse width W _P0, the pressurization rate S _IO, which had been stored calculated and in ST _4, the pulse wave stored further at ST7 A predetermined calculation is performed using the number of vibrations N _P0 as an input value to calculate a pulse width W _PX so that a larger appropriate number of pulse wave vibrations N _P can be obtained (see FIG. 3). In addition,
In this embodiment, the output value is the pulse width _WPX , but other parameters may be used as long as an appropriate number of pulse wave vibrations can be obtained. Further, the content of the above calculation is not particularly limited, and may be based on, for example, fuzzy logic.

When the pulse width W _PX of the pulse supplied to the pump is determined as described above, the MPU 8 controls the pump 2 with the pulse width W _PX to start pressurizing the cuff again (ST10). ). Then, the process returns to ST3, the operation conditions of the after-pressure, i.e., the applied voltage E _P, the pulse width W _PX, after storing the inflation speed S _IX (ST3, ST4), the process as again pressurizing process (ST5 ). In this case, since the pressurizing condition is set so as to obtain an appropriate pressurizing speed, the systolic blood pressure value can be estimated, the depressurization process is started from the appropriate cuff pressure value, and the blood pressure value is determined appropriately (ST6 to ST6). ST14).

FIG. 4 is a simplified illustration of the operation of the pressurizing process described above. That is, in the first pressurization process (left side in FIG. 4), the pressurization condition (pulse width W _P0
), Only two vibrations of the pulse wave can be captured, and the systolic blood pressure value cannot be estimated. Then, the cuff pressure is rapidly reduced, and the corrected pressurizing condition (pulse width W
_PX, etc.) to capture five pulse wave vibrations. From the change in the pulse wave amplitude, the systolic blood pressure value is estimated at the cuff pressure corresponding to, for example, the point of the amplitude value 0.5A _MAX , and the pressurization is stopped at a value based on this value. The blood pressure is measured during the process.

[0019]

As described above, in the electronic sphygmomanometer according to the present invention, even if the estimation of the systolic blood pressure value fails in the process of increasing the cuff pressure, the cuff pressure is immediately reduced, and the appropriate condition is set again. Since the cuff is pressurized at the time, the subject does not suffer pain, and the decompression process is not started due to insufficient pressurization.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram of an electronic sphygmomanometer according to one embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of the electronic sphygmomanometer of FIG. 1;

FIG. 3 illustrates parameters and the like for determining a pulse width.

FIG. 4 is a time chart for explaining the operation of the electronic sphygmomanometer of FIG. 1;

FIG. 5 is a diagram for explaining a blood pressure determination method in an oscillometric electronic sphygmomanometer.

[Explanation of symbols]

 1 Cuff 2 Pump 3 Rapid exhaust valve 4 Slow exhaust valve 5 Pressure sensor 8 MPU

──────────────────────────────────────────────────続 き Continuing on the front page (72) Osamu Shirasaki, Inventor 17 Science Center Building, Chudoji Minamicho, Shimogyo-ku, Kyoto Omron-la If-Science Research Institute, Inc. (56) References JP-A-63-281622 (JP, A) 55-125846 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) A61B 5/00-5/03

Claims (3)

(57) [Claims] 1. A cuff for compressing a living artery, a pressurizing means for pressurizing the cuff, a pressure sensor for detecting a pressure in the cuff, and a cuff pressure signal detected by the pressure sensor superimposed on the cuff pressure signal. Pulse wave extracting means for extracting a pulse wave signal
Pulse wave amplitude calculating means for calculating the amplitude value of the pulse wave signal extracted by the pulse wave extracting means, and pressurization of the cuff pressure is stopped based on the temporal transition of the pulse wave amplitude calculated by the pulse wave amplitude calculating means. Pressurizing stop point calculating means for calculating a point, pressurizing stop means for stopping the operation of the pressurizing means when the cuff pressure reaches the pressurizing stop point, and gradually reducing the cuff pressure after stopping the pressurizing. An electronic sphygmomanometer comprising: a pressure reducing means for performing pressure reduction; and a blood pressure determining means for determining a blood pressure value in a process of reducing the cuff pressure. A pulse wave number storing means for storing the number of vibrations of the pulse wave extracted in the pressurizing process; and a cuff pressure for rapidly decreasing the cuff pressure when the pressurizing stop point calculating means cannot calculate the pressurizing stop point. Dive means; If the pressurization stop point cannot be calculated, a part or all of the operation parameters are corrected from a predetermined relational expression based on the pulse wave frequency stored in the pulse wave number storage means and the operation parameters. An electronic sphygmomanometer, comprising: operating condition correcting means for performing the operation; and re-driving means for operating the pressurizing means under the corrected operating conditions. 2. The operating parameters stored in the operating state storing means according to claim 1, wherein the operating parameters include a cuff pressure application speed, a voltage value applied to the application device, a pulse width of a pulse wave supplied to the application device, An electronic sphygmomanometer, wherein the electronic sphygmomanometer is any one selected from the group consisting of: 3. The electronic sphygmomanometer according to claim 1, wherein the operating parameter corrected by the operating condition correcting means is a pulse width of a pulse wave supplied to the pressurizing means.