JP3008582B2 - 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 sphygmomanometer, and more particularly to an electronic sphygmomanometer capable of appropriately stopping pressurization.

[0002]

2. Description of the Related Art In an electronic sphygmomanometer, for example, the cuff pressure is changed with time (see FIG. 3A), and the amplitude of a pulse wave superimposed on the cuff pressure is changed (FIG. 3B). ) To calculate the blood pressure. FIG. 3B shows a change in the pulse wave amplitude in the process of reducing the cuff pressure of such a sphygmomanometer, and point P indicates the maximum amplitude point ( _AMAX ). Point D is 0.7 A from the maximum amplitude point.
_The point having an amplitude of _MAX , and the point S is a point having an amplitude of 0.5 A _MAX with respect to the maximum amplitude point. Then, for example, the systolic blood pressure (systolic blood pressure) and the diastolic blood pressure (diastolic blood pressure) are determined from the respective points in FIG. 3A corresponding to the points S and D.

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 based on the estimated value The value P is determined, and the cuff pressure slightly drops immediately after the stop of pressurization.
In consideration of the above, the pressurization stop point is determined by adding the cuff pressure drop ΔP ′ to the pressurization set value P.

[0004]

By the way, the rapid cuff pressure drop ΔP ′ (according to the change in the air temperature in the cuff) that occurs immediately after the stop of the pressurization is caused by the speed of pressurizing the cuff, the time required for pressurization, It varies greatly depending on the power applied to the pump and the volume of air in the cuff. Specifically, the cuff pressure drop ΔP ′ tends to increase as the pressurization speed increases (the pressurization time decreases), and the cuff pressure drop ΔP ′ increases as the air volume in the cuff decreases.

Therefore, in the conventional blood pressure monitor described above,
Even if the pressurization set value is set to an appropriate value, simply adding the fixed value ΔP to the pressurization set value P to determine the pressurization stop point will result in insufficient pressurization or excessive pressurization in the depressurization process. A pressure problem arises. Hereinafter, with reference to FIGS. 4 to 6,
This point will be further described. For example, when a pressurization set value P is determined based on the systolic blood pressure value estimated in the pressurization process, and a fixed value ΔP is added thereto to determine a pressurization stop point, the fixed value ΔP and the cuff pressure drop amount are determined. If ΔP ′ is equal (see FIG. 6), cuff pressure evacuation is started at a cuff pressure point T equal to the pressurization set value P, and ideal blood pressure measurement can be performed.

However, when the cuff pressure drop amount ΔP ′ is larger than the added fixed value ΔP (see FIG. 4), the slow speed exhaust starts from a cuff pressure value lower than the pressurization set value P, resulting in insufficient pressurization. State. On the other hand, when the cuff pressure drop amount ΔP ′ is smaller than the added fixed value ΔP (see FIG. 5), the evacuation starts at a cuff pressure value higher than the pressurization set value P, resulting in an overpressurized state. In any case, the setting of the pressurization stop point is inadequate.

The present invention has been made in view of this problem, and estimates the amount of cuff pressure drop that occurs immediately after stopping pressurization in advance, and always stops pressurization at an appropriate cuff pressure value. It is an object to provide an electronic sphygmomanometer.

[0008]

To achieve the above object, a sphygmomanometer according to claim 1 comprises a cuff for compressing a living artery, a pressurizing means for pressurizing the inside of the cuff, and a cuff pressure set to a predetermined value. Pressure stop means for stopping the operation of the pressurizing means when the pressure reaches, a pressure reducing means for gradually reducing the cuff pressure after the pressure stop, and a blood pressure determining means for determining a blood pressure value in the process of reducing the cuff pressure. In the electronic sphygmomanometer, a pressurization set value determining means for determining a cuff pressure value (pressurization set value) to be a starting point of the pressure reducing process, and a pressurizing means based on an operation parameter when the cuff pressure is increased. Pressurization stop point determining means for estimating the cuff pressure drop immediately after the pressure stop, adding the cuff pressure drop to the pressurization set value, and determining the pressurization stop point is provided.

According to a second aspect of the present invention, in the blood pressure monitor according to the first aspect, the operating parameters include a cuff pressure increasing speed, a cuff increasing time, an amount of electric power supplied to the pressurizing means, and an inhalant in the cuff. , Or any combination selected from among these capacities.

[0010]

The pressure setting value determination means determines a pressure setting value from which cuff pressure value the cuff pressure reduction process should be started to start blood pressure measurement. Since this pressurization set value is a cuff pressure value at which the depressurization process of the cuff pressure should be started, it is determined based on, for example, the systolic blood pressure value estimated in the cuff pressure pressurization process. The determination method is not particularly limited.

[0011] The pressurization stop point determining means determines the operating parameters of the pressurizing means in the process of pressurizing the cuff pressure, such as the pressurizing speed of the cuff pressure, the pressurizing time of the cuff, the amount of power supplied to the pressurizing means, The cuff pressure drop immediately after the stop of pressurization is estimated based on the volume of the inhaled matter in the cuff. Then, the estimated cuff pressure drop amount is added to the pressurization set value to determine the pressurization stop point. Then, the pressurization stopping means pressurizes the cuff pressure to the pressurization stop point and stops the pressurization.

Then, immediately after the cuff pressure is stopped, the cuff pressure drops sharply. However, since the cuff pressure is excessively increased in advance by the amount of the decrease, the pressure reduction by the pressure reducing means is reduced by the pressure setting value determining means. It starts from the determined pressurization set value.

[0013]

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 a characteristic operation part of the operation of the electronic sphygmomanometer shown in FIG.
This embodiment is an example in which the pressurization stop point is determined based only on the pressurization speed among the pressurization speed, pressurization time, and applied power which are the operation parameters of the pump 2. 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 operates the pump 2
To start pressurization (step ST (hereinafter abbreviated as ST) 1). Next, the MPU 8 detects the pressure speed while maintaining the pressure of the cuff pressure (ST2). Then, the pressurizing speed is compared with two appropriately set thresholds to determine in which range the pressurizing speed is high, medium, or low (ST3).

When the pressurizing speed is high, the drop amount ΔP ′ of the cuff pressure after stopping the pressurization of the cuff pressure is also large, so that the pressurizing set value P
The value of the added value ΔP to be added to is increased (ST4).
Conversely, when the pressurizing speed is low, the value of the added value ΔP added to the pressurized set value P is set small because the drop amount ΔP ′ of the cuff pressure after the stop of pressurizing the cuff pressure is small (ST6). When the pressurizing speed is at the middle level, a medium addition value ΔP
(ST5).

After setting the value of the addition value ΔP in this way, the MPU 8 continues to drive the pump 2 to increase the cuff pressure. Then, the pressure stop point is determined by adding the cuff pressure value (pressurization set value) P at which the pressure reduction process is to be started and the addition value ΔP, and pressurization is stopped when the pressure stop point is reached (ST).
7). Then, the cuff pressure drops sharply by ΔP ',
In the pressurization process, extra pressurization is performed in anticipation of this drop ΔP ′, and the subsequent operation is started from the cuff pressure level of the pressurization set value P. That is, when the MPU 8 operates the slow exhaust valve 4 to enter the pressure reducing process, the cuff pressure value is the pressure setting value P. Thereafter, the blood pressure value is measured by the same operation as the conventional blood pressure monitor (ST8).

In the flowchart of FIG. 2, the addition value ΔP is set in consideration of only the pressurization speed. However, the addition value ΔP is considered in consideration of other operation parameters, such as the pressurization time and the power applied to the pump. Is set in the same manner as in the case of FIG. Also, if the pressurizing speed, pressurizing time, and the applied power of the pump are detected, the air volume in the cuff can be estimated based on these values, and if the added value ΔP is determined in consideration of this air volume, The accuracy of estimating the cuff pressure drop amount ΔP ′ is further improved.

The cuff pressure drop ΔP ′ may be estimated by calculating all of the pressurizing speed, pressurizing time, electric power applied to the pump, and the air volume in the cuff, or these parameters may be set as desired. And the cuff pressure drop amount ΔP ′ may be estimated. Further, in the above embodiment, the oscillometric electronic sphygmomanometer is described as an example, but the present invention is also applicable to a K-sound electronic sphygmomanometer.

[0019]

As described above, the electronic sphygmomanometer according to the present invention estimates the drop amount of the cuff pressure at the time of stopping the pressurization in consideration of the parameter at the time of pressurization, and uses this value as the pressurization set point. And the pressure stop point is set. Therefore, the depressurization process of the cuff pressure will be started from the initially set pressurization set point, and the problem of insufficient pressurization and overpressurization does not occur, and therefore,
Ideal blood pressure measurement.

[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 a characteristic operation of the electronic sphygmomanometer of FIG. 1;

FIG. 3 is a diagram for explaining a blood pressure determination method in an oscillometric electronic sphygmomanometer.

FIG. 4 is a diagram illustrating a pressure reduction process in a state of insufficient pressure.

FIG. 5 is a diagram illustrating a pressure reduction process in an over-pressurized state.

FIG. 6 is a view showing an ideal pressure reduction process.

[Explanation of symbols]

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

────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Yoshinori Miyawaki 17 Science Center Building, Chudoji Minamicho, Shimogyo-ku, Kyoto Inside Omronla If-Science Research Institute, Inc. (56) References JP-A-55-52738 (JP, A) Kaihei 1-256930 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) A61B 5/00-5/03

Claims (2)

(57) [Claims] 1. A cuff for compressing a living artery, a pressurizing means for pressurizing the inside of the cuff, a pressurizing stop means for stopping the operation of the pressurizing means when the cuff pressure reaches a predetermined value, and a pressurizing stop. An electronic sphygmomanometer comprising a pressure reducing means for gradually reducing the cuff pressure later and a blood pressure determining means for determining a blood pressure value in the process of reducing the cuff pressure, wherein a cuff pressure value to be a starting point of the pressure reducing process (pressurization setting Value), and the amount of cuff pressure drop immediately after the stop of pressurization is estimated based on operating parameters when the pressurizing means increases the cuff pressure. An electronic sphygmomanometer provided with a pressurization stop point determining means for determining a pressurization stop point by adding to a pressure set value. 2. The operating parameter according to claim 1, wherein the operating speed is selected from a cuff pressure pressurizing speed, a cuff pressurizing time, an amount of electric power supplied to the pressurizing means, and a volume of an inhalation in the cuff. An electronic sphygmomanometer, being any one or any combination.