JPH01285244A - Pulse wave detector - Google Patents

Abstract

PURPOSE:To rapidly judge whether a press position is proper, by judging whether the press position of a pulse wave sensor is proper based on whether the amplitude of a pressure pulse wave when the pressing force of the pulse wave sensor reaches predetermined pressure becomes a predetermined value or less. CONSTITUTION:Prior to determining the optimum pressing force of a pulse wave sensor 20, the pressure in a pressure chamber 22 (the pressing force of the pulse wave sensor 20) is increased at a relatively high speed and it is judged whether the press position of the pulse wave sensor 20 is proper, based on whether the amplitude of a pressure pulse wave when the pressure in the pressure chamber 22 reaches predetermined pressure Pa becomes a reference value or less and, when the press position is judged to be improper, that effect is displayed on a display/recording apparatus 34 and, therefore, the press position of the pulse wave sensor 20 can be judged still more rapidly without waiting until the detection of the pressure pulse wave is started.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a pulse wave detection device for detecting pulse waves generated from an artery.

Conventional technology A pulse wave sensor is provided that is pressed onto an artery on the surface of a living body, and the optimal pulse wave sensor is determined based on the pressure pulse wave collected as the pressing force of the pulse wave sensor is changed relatively gradually. A pulse wave detection device that determines the pressing force has been considered. In such a pulse wave detection device, the pulse wave sensor is usually placed on an artery located directly above a bone in the living body, and the pressure of the pulse wave sensor is gradually changed to detect the pulse wave sensor. The maximum amplitude pressure pulse wave is determined based on the fact that the amplitude of the pressure pulse wave sequentially collected from the pulse wave sensor increases gradually and then gradually decreases during the process of gradually crushing the artery between the pulse wave sensor and the bone. The pressing force at which the pressure pulse wave with the maximum amplitude is collected is determined as the optimum pressing force.

Problems to be Solved by the Invention However, when a pulse wave sensor presses an artery on the surface of a living body, if there is no bone supporting the artery directly below the artery, the pressing force of the pulse wave sensor Since the artery is difficult to collapse, the phenomenon of increase/decrease in the amplitude of the pressure pulse wave cannot be obtained normally, and the optimum pressing force of the pulse wave sensor may not be accurately determined. In such cases, it is necessary to change the pressing position of the pulse wave sensor, but when determining the optimal pressing force of the pulse wave sensor, the pressing force can be changed gradually at a predetermined speed. , there was a problem in that it took a relatively long time to determine whether the pressure position of the pulse wave sensor was appropriate because it was not known that the pressure position of the pulse wave sensor was inappropriate until pressure pulse wave detection started. .

The present invention has been made against the background of the above circumstances, and its purpose is to quickly determine whether or not the pressing position of the pulse wave sensor is appropriate before determining the optimum pressing force. An object of the present invention is to provide a pulse wave detection device.

Means for Solving the Problems In order to achieve the above object, the present invention provides a pulse wave detection device of the type described above, and as shown in the claim correspondence diagram of FIG. Prior to determining the optimum pressing force of the pulse wave sensor, preliminary pressing means relatively rapidly increases the pressing force of the pulse wave sensor to a predetermined pressure; and (b) generated by the preliminary pressing means. The pressure of the pulse wave sensor is determined based on whether the amplitude of the pressure pulse wave becomes equal to or less than a predetermined value when the pressure of the pulse wave sensor reaches the predetermined predetermined pressure. It is characterized by including a pressing position determining means for determining whether the position is appropriate.

Operation and Effects of the Invention According to the pulse wave detection device configured in this way, before determining the optimum pressing force of the pulse wave sensor by gradually changing the pressing force of the pulse wave sensor, the preliminary pressing force is determined. By the means, the pressing force of the pulse wave sensor is relatively rapidly increased to a predetermined pressure, and a pressure pulse wave is generated when the pressing force of the pulse wave sensor reaches the predetermined pressure. Based on whether or not the amplitude of the pulse wave sensor is less than or equal to a predetermined value, the pressing position determining means determines whether the pressing position of the pulse wave sensor is appropriate or not, and the detection of the pressure pulse wave starts as in the conventional method. It is possible to more quickly determine whether the pressing position of the pulse wave sensor is appropriate without waiting until the pulse wave sensor is pressed.

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

In FIG. 2, reference numeral 10 denotes a housing having a cylindrical shape with a bottom, and is adapted to be detachably attached to the wrist 16 with a band 14 with its open end facing the body surface 12 of the human body. Inside the housing IO, a pulse wave sensor 20 is provided via a diaphragm 18 so as to be relatively movable and protrude from the open end of the housing 10, and a pressure chamber 22 is formed by the housing 10 and the diaphragm 18. ing. Pressure fluid such as pressurized air is supplied into the pressure chamber 22 from a fluid supply source 24 via a pressure regulating valve 26, so that the pulse wave sensor 20 adjusts to the pressure inside the pressure chamber 22. It is pressed against the body surface 12 with a corresponding pressing force.

The pulse wave sensor 20 has a pressure sensitive element such as a pressure sensitive diode provided on the pressing surface 28 of a semiconductor chip made of, for example, single crystal silicon, and has a pressure sensitive element such as a pressure sensitive diode.
A pressure vibration wave, that is, a pressure pulse wave, generated from the body surface 12 and transmitted to the body surface 12 is detected.

In this embodiment, the body surface 12 corresponds to the biological surface, and the radial artery 30 corresponds to the artery. The electrical signal output from the pulse wave sensor 20, ie, the pulse wave signal SM representing the pressure pulse wave, is supplied to the control device 32. The control device 32 is
It is configured with a microcomputer and sends a drive signal S to the pressure regulating valve 26 according to a predetermined program.
D is output to adjust the pressure inside the pressure chamber 22, and the pressure inside the pressure chamber 22 is adjusted.
The appropriateness of the pressing position of the pulse wave sensor 20 is determined based on a pulse wave signal SM collected when the pressure inside the pressure chamber 22 is rapidly increased to a predetermined pressure P, which will be described later. The optimum pressing force of the pulse wave sensor 20 is determined based on the wave signal SM, while the pressure pulse wave is detected based on the pulse wave signal SM collected at the optimum pressing force, and the display recording signal SI is output. The detected pressure pulse wave number is displayed and recorded on the display/recording device 34.

Next, the operation of the pulse wave detection device configured as described above will be explained according to the flowchart of FIG. 3.

First, when the power is turned on, step S1 is executed, and it is determined whether a starting switch (not shown) has been operated to the ON state. If this determination is negative, step S1 is repeatedly executed and the standby state is set; however, if it is determined that the start switch is in the ON state, step S2 is executed and the pressure chamber is placed in a standby state. Pressure fluid is supplied into the pressure chamber 22, and the pressure within the pressure chamber 22 is relatively rapidly increased to a predetermined pressure P, and the pulse wave sensor 20 is pressed against the body with a pressing force corresponding to the predetermined pressure P. Pressed against surface 12. A in FIG. 4 shows this point. Preferably, the predetermined pressure P is as shown in FIG. 5, which will be described later.
A pressure that is sufficiently higher than the pressure P in the pressure chamber 22 corresponding to the optimal pressing force of the pulse wave sensor 20, for example, 200 m
The pressure is set to about mHg. In this example,
The above step S2 corresponds to a preliminary pressing means.

Next, the appropriateness of the pressing force of the pulse wave sensor 20 is determined between A and 8 in FIG. That is, first step S
By executing step S4, for example, one pressure pulse wave is collected at the predetermined pressure P.
In step S3, the amplitude A of the pressure pulse wave collected in step S3 is calculated. Next, step S5 is executed to immediately start discharging the pressure inside the pressure chamber 22, and then step S6 is executed, whereby the amplitude A+ calculated in step S4 is set to a predetermined reference value A. .

It is determined whether or not the following is true. This standard value A.

is determined in advance in relation to the predetermined pressure P1 and the like. An example of the reference value A8 is shown in FIG. 5, which will be described later.If the determination in step S6 is affirmative, the radial bone 36 is present immediately below the radial artery 30, as shown in FIG. This indicates that the radial artery 30 is suitably crushed as the pressing force of the pulse wave sensor 20 increases.
It is determined that the pressing position of 0 is appropriate, and step S7
By executing this, rate-limiting pressure increase in the pressure chamber 22 is started. B in FIG. 4 shows this point.

Next, step S8 is executed, whereby pressure pulse waves are sequentially sampled in the rate-limiting pressure increase process, and the amplitude A of each sampled pressure pulse wave is calculated. At this time,
The amplitude A is the pressure inside the pressure chamber 22, that is, the pulse wave sensor 2
As the pressing force of 0 increases, for example, as shown in FIG. 5, the pressure increases gradually and then gradually decreases. Then step S9 is executed to determine the maximum amplitude A1 . is determined and its maximum amplitude As
The pressure P corresponding to +mx is determined as the pressure inside the pressure chamber 22 at the optimum pressing force of the pulse wave sensor 20. Next, step S10 is executed, and the pressure within the pressure chamber 22 is adjusted to the pressure P and held at the pressure P. C in FIG. 4 shows this point. Then, in this state, detection of the pressure pulse wave is started, and the detected pressure pulse wave is displayed and recorded on the display/recording device 34.

On the other hand, if the determination in step S6 is negative,
Since the radial bone 36 is not present immediately below the radial artery 30, indicating that the radial artery 30 is not suitably crushed in response to the increase in the pressing force of the pulse wave sensor 20, the pulse When it is determined that the pressing position of the pulse wave sensor 20 is not appropriate and step 311 is executed, for example, a predetermined display indicating that the pressing position of the pulse wave sensor 20 is inappropriate is displayed on the display/recording device 34. At the same time, the following step 312 is executed, and the starting switch is automatically switched to the OFF state, and then step St is executed again to enter the standby state.

Therefore, in this embodiment, the step S6 corresponds to the pressed position determining means. Then, after changing the mounting position of the housing 10 and changing the pressing position of the pulse wave sensor 20 in such a standby state, when the start switch is operated to the ON state again, steps 32 and subsequent steps are performed as in the case described above. It will be executed.

Here, conventionally, when the pressure of the pulse wave sensor 20 is increased at a rate-limiting rate at an inappropriate pressing position as described above, the amplitude A of the pressure pulse wave is, for example, as shown in FIG. As the pressing force of the sensor 20 increases, it does not gradually increase and then decrease, but after a certain level of pressing force, it remains a substantially constant value regardless of the increase in the pressing force, making it possible to accurately determine the optimal pressing force of the pulse wave sensor 20. There were cases where it was not possible to make a decision. In such a case, the pulse wave sensor 2 is operated until pressure pulse wave detection is started.
Since it is not known that the pressing position of 0 is inappropriate, it takes a relatively long time to determine whether the pressing position of the pulse wave sensor 20 is appropriate.

On the other hand, according to the pulse wave detection device of this embodiment, before determining the optimal pressing force of the pulse wave sensor 20, the pressure in the pressure chamber 22 (the pressing force of the pulse wave sensor 20) is compared. The pulse wave sensor The suitability of the pressure position 20 is determined, and if it is determined that the pressure position is inappropriate, a message to that effect is displayed on the display/recording device 34, so that pressure pulse waves cannot be detected as in the conventional method. The display/recording device 34 without waiting until the
The pressed position of the pulse wave sensor 20 can be determined more quickly based on the display displayed on the screen.

Further, according to this embodiment, there is an advantage that the appropriateness of the pressing position of the pulse wave sensor 20 can be easily determined by simply comparing the amplitude A and the reference value As without using a complicated algorithm. be.

In the above-mentioned embodiment, only one pressure pulse wave is collected after the rapid pressure increase in the pressure chamber 22, but this is not necessarily necessary. For example, multiple pressure pulse waves may be collected and their amplitudes averaged. may be calculated, and the average value may be compared with the reference value As.

Furthermore, in the above-mentioned embodiment, the pressing position of the pulse wave sensor 20 is changed by changing the mounting position of the housing lO. It is also possible to provide a driving means for driving and to automatically move the pulse wave sensor to an appropriate pressing position when it is determined that the pressing position of the pulse wave sensor is inappropriate. be. In this case, there is no need to display that the pressed position is inappropriate.

Furthermore, in the above embodiment, the present invention is applied to a pulse wave detection device of a type that determines the optimal pressing force based on the pressure pulse wave collected when the pressing force of the pulse wave sensor is gradually increased. Although the case has been described, the present invention can also be applied to a pulse wave detection device of a type that determines the optimum pressing force based on a pressure pulse wave collected when the pressing force is gradually decreased.

FIG. 6 is an example of a time chart showing the operation of the device. In this case, as a result of determining whether or not the pressing position of the pulse wave sensor is appropriate, if it is determined that the pressing position force is appropriate, the pressure inside the pressure chamber 22 is rapidly evacuated as in the above-mentioned embodiment. After that, the predetermined pressure P is increased without increasing the pressure again at a rate-limiting rate.
Since the optimum pressing force is determined in the process of rate-limiting exhaustion from pressure chamber 2, as in the above-mentioned embodiment, before determining the optimum pressing force,
2 inside 2. There is an advantage that no time is required for rapid exhaustion.

Further, in the above-mentioned embodiment, the case where pressure pulse waves are detected from the radial artery 30 has been described, but the present invention can also be applied when detecting pressure pulse waves from other arteries other than the radial artery, such as the dorsalis pedis artery. The effect of this can be obtained.

In addition, various changes may be made to the present invention without departing from the spirit thereof.

[Brief explanation of the drawing]

FIG. 1 is a complaint correspondence diagram. FIG. 2 is a diagram showing a circuit diagram of a pulse wave detection device which is an embodiment of the present invention, and is a partially sectional view. FIG. 3 is a flowchart for explaining the operation of the apparatus shown in FIG. 2. FIG. 4 is an example of a time chart showing the operation of the device shown in FIG. FIG. 5 is a diagram showing the relationship between the amplitude of the pressure pulse wave and the pressure in the pressure chamber 22 (the pressing force of the pulse wave sensor), and shows an example when the pressing position of the pulse wave sensor is appropriate. . FIG. 6 is a diagram for explaining another embodiment of the present invention, and corresponds to FIG. 4. FIG. 7 is a diagram corresponding to FIG. 5 showing the relationship between the amplitude of the pressure pulse wave and the pressing force of the pulse wave sensor, and shows an example where the pressing position of the pulse wave sensor is not appropriate. 12; Body surface (biological surface) 20: Pulse wave sensor 30; Radial artery (artery) Applicant: Korin Electronics Co., Ltd. Figure 1 Figure 3 Figure 4 (pressure, force) Figure 6 7i

Claims (1)

[Scope of Claims] A pulse wave sensor is provided that is pressed onto an artery on the surface of a living body, and the pulse wave is generated based on a pressure pulse wave collected as the pressing force of the pulse wave sensor is changed relatively gradually. A pulse wave detection device of a type that determines an optimal pressing force of a sensor, and prior to determining the optimal pressing force of the pulse wave sensor,
preliminary pressing means for relatively rapidly increasing the pressing force of the pulse wave sensor to a predetermined pressure; and the pressing force of the pulse wave sensor generated by the preliminary pressing means increases to the predetermined pressure. Pressure position determining means for determining whether or not the press position of the pulse wave sensor is appropriate based on whether or not the amplitude of the pressure pulse wave when the pulse wave sensor reaches the predetermined value is below a predetermined value. Pulse wave detection device.