JPH04176439A - Acceleration pulse wave detector - Google Patents

Abstract

PURPOSE:To improve accuracy in diagnosis of blood circulating condition of an organism by correcting an acceleration pulse wave based on a blood pressure value of the organism obtained by a blood pressure value determining means to remove effect of the blood pressure value of the organism on the shape of the acceleration pulse wave. CONSTITUTION:A finger point pulse wave sensor 28 is provided to detect changes in capacity of blood within a blood capillary at a peripheral part of an organism and it detects capacity pulse waves at finger tips of hands or feet based on a change in quantity of transmission light or quantity of reflected light of infrared rays and a change in impedance. A flow control valve 14 and a pump 16 are operated to execute the measurement of a blood pressure and a blood pressure value is shown on a display device 40 while a pulse wave from a finger point pulse wave sensor 28 undergoes a quadratic differentiation to calculate an acceleration pulse wave. For example, a correction factor determined based on an average blood pressure value from a predetermined relationship is multiplied by the acceleration pulse wave calculated to correct. Thus, a correct acceleration pulse wave is obtained not affected by the blood pressure of a person to be measured thereby enabling accurate judgment of blood circulating condition based on the shape of the acceleration pulse wave.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a device for detecting an accelerated pulse wave of a living body.

Conventional technology For example, as described in Japanese Unexamined Patent Application Publication No. 57-93036, a volume pulse wave generated from the peripheral blood vessels of a living body is
An accelerated pulse wave detection device has been proposed that obtains an accelerated pulse wave by performing second-order differentiation.

This accelerated pulse wave reflects the blood circulation state of the living body and is considered to be one of the important indicators representing the patient's circulatory function state.

Problems to be Solved by the Invention By the way, the conventional accelerated pulse wave detection device described above extracts the waveform characteristics of the accelerated pulse wave and attempts to diagnose the blood circulation state of the patient. The waveform is easily influenced by the physiological state of the patient, and there are cases where sufficient diagnostic accuracy cannot be obtained.

The present invention has been made against the background of the above circumstances,
The purpose is to provide an accelerated pulse wave detection device in which the accelerated pulse wave is not easily affected by the physiological state of the patient and can improve the accuracy of diagnosis.

Means for Solving the Problems In order to achieve the above object, the inventors of the present invention have conducted various studies and found that one of the factors that affect the accelerated pulse wave is the blood pressure value of the living body.

The present invention has been made based on this knowledge.

That is, the gist of the present invention is to provide a pulse wave detection means for detecting a pulse wave generated from an artery of a living body, and to obtain an accelerated pulse wave by performing second differentiation on the pulse wave detected by the pulse wave detection means. An accelerated pulse wave detection device of the type comprising: (a) a compression means wound around a part of the living body, and using the compression means to determine the blood pressure value of the living body; The present invention includes a blood pressure value determining means, and (b) an accelerated pulse wave correction means for correcting the accelerated pulse wave based on the blood pressure value of the living body obtained by the blood pressure value determining means.

In this manner, the accelerated pulse wave is corrected by the accelerated pulse wave correction means based on the blood pressure value of the living body obtained by the blood pressure value determining means, so that the accelerated pulse wave of the blood pressure value of the living body is corrected. The influence on the shape is removed, and the accuracy of diagnosis of the blood circulation state of the living body can be suitably increased.

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

In FIG. 1, a cuff 10 wrapped around the base of a living body's limbs, for example, the upper arm, includes a pressure sensor 12 that detects the pressure within the cuff 10 and generates a pressure signal SP, and a pressure sensor 12 that controls the pressure within the cuff 10. The flow rate control valve 14 is connected to a pump 16 that supplies pressure into the cuff 10 via a conduit 18.

The pressure signal SP output from the pressure sensor 12 is passed through a bandpass filter 20 for passing the frequency component of a pulse wave, which is a pressure vibration synchronized with the heartbeat of the living body, and a bandpass filter 20 for passing the frequency component of the pulse wave, which is a pressure vibration synchronized with the heartbeat of the living body, and a bandpass filter 20 for passing the static pressure component in the cuff 10. The low pass filter 22 is supplied with the low pass filter 22. The pulse wave signal SM discriminated by the bandpass filter 20 and the cuff pressure signal SK discriminated by the low-pass filter 22 are converted into digital signals by the A/D converter 24 and then supplied to the CPU 26 .

The volume pulse wave signal SY output from the fingertip pulse wave sensor 28 is supplied to the A/D converter 32 through a bandpass filter 30 that passes the frequency component of the volume pulse wave, where it is converted into a digital signal. The signal is supplied to the CPU 26. The fingertip pulse wave sensor 28 detects changes in blood volume in capillaries in the peripheral parts of a living body, and detects changes in the volume of blood in capillaries in the peripheral parts of a living body, and detects changes in the amount of transmitted or reflected light of infrared rays and impedance. is configured to detect based on a change in .

The CPU 26 constitutes an electronic control device consisting of a so-called microcomputer together with a ROM 34, a RAM 36, an output interface 38, etc.
36, the input signal is processed according to a program stored in advance in the ROM 34, the flow control valve 14 and the pump 16 are operated to perform blood pressure measurement, and the blood pressure value is displayed on the display 40. , an accelerated pulse wave is calculated by applying a secondary part to the pulse wave from the fingertip pulse wave sensor 28, and the shape of the accelerated pulse wave is further corrected based on the blood pressure value, and then displayed on the display 40. .

FIG. 2 is a functional block diagram of the accelerated pulse wave detection device configured as described above. In the figure, differentiating means 50
Then, an accelerated pulse wave is generated by subjecting the pulse wave outputted from the pulse wave detecting means 52 corresponding to the fingertip pulse wave sensor 28 to second-order differentiation. The blood pressure value determining means 54 uses the compression means 56 corresponding to the cuff 10 to determine the blood pressure value of the living body. Then, the accelerated pulse wave correction means 5
8, the accelerated pulse wave is corrected based on the blood pressure value,
The corrected pulse wave is output.

Hereinafter, the operation of this embodiment will be explained according to the flowchart shown in FIG.

In FIG. 3, in the blood pressure value determination routine of step S1 corresponding to the blood pressure value determination means 54, the flow rate control valve 14 and the pump 16 are operated in accordance with a well-known order, so that the pressure in the cafe 0 is adjusted to the measured value. The patient's blood pressure is raised to a level higher than the patient's systolic blood pressure value, and then gradually lowered, and during this gradual pressure reduction process, the pulse wave signal SM and cuff pressure signal SK are sequentially read. Then, according to the oscillometric method, for example, the cuff pressure at the maximum point of the difference in amplitude during the increasing and decreasing processes of the amplitude value of the pulse wave signal SM is determined as the systolic blood pressure value and the diastolic blood pressure value, and the pulse wave signal SM The cuff pressure at the maximum amplitude of the signal SM is determined as the mean blood pressure value.

In the subsequent step S2, the volume pulse wave SY is read, and in step S3 corresponding to the differentiating means 50, the volume pulse wave signal SY is subjected to second-order (twice) differentiation, thereby obtaining the result shown in FIG. Accelerated pulse wave A before correction shown in broken line
SM" (1) is generated. Next, in step S4 corresponding to the accelerated pulse wave correction means 58, the accelerated pulse wave is corrected based on the blood pressure value of the subject determined in step S1. For example, the fifth
A correction coefficient K is determined based on the average blood pressure value from a predetermined relationship shown in the figure, and this correction coefficient is
The accelerated pulse wave ASM′ (t,
) to obtain the corrected accelerated pulse wave ASM(t) shown by the solid line in FIG.

Then, in step S5, the accelerated pulse wave A after the above correction
Each peak position, which is a waveform feature of SM (t), is determined by further differentiation, and the peripheral circulation state is automatically determined based on the peak position, and in the subsequent step S6, the determination result is determined. It is displayed on the display 40.

As described above, according to the present embodiment, in step S4, the accelerated pulse wave ASM" (1) is corrected based on the blood pressure value of the subject determined in step S1, so that the corrected accelerated pulse wave Since the wave ASM(t) is obtained, an accurate accelerated pulse wave A that is not affected by the blood pressure value of the subject is obtained.
SM (t) is obtained. Therefore, the accelerated pulse wave AS
The blood circulation state can be accurately determined based on the shape of M (t).

Although the embodiment of the present invention has been described above based on the drawings, the present invention can also be applied to other aspects.

For example, in the above-mentioned embodiment, the acceleration pulse wave ASM" (1) before correction is multiplied by the correction coefficient K obtained based on the actual blood pressure value from the relationship shown in FIG. However, correction may be applied only to waveform portions or bands that are easily affected by blood pressure values.

Further, in the above-mentioned embodiment, the fingertip pulse wave sensor 28 that detects the fingertip pulse wave from the fingertips of the fingers or toes was used.
It may also be possible to detect a plethysmogram, which is a change in blood volume in a peripheral blood vessel, based on a change in reflected light on the skin of the forehead, limbs, or the like.

It should be noted that 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 block diagram illustrating the configuration of an embodiment of the present invention. FIG. 2 is a functional block diagram illustrating the functions of the embodiment shown in FIG. 1. FIG. 3 is a flowchart illustrating the operation of the apparatus of FIG. 1. Figure 4 shows the third
It is a figure which shows the example of the accelerated pulse wave obtained by the operation|movement of a figure. FIG. 5 is a diagram illustrating the relationships used in the operation of FIG. 50: Differentiation means 52: Pulse wave detection means 54: Blood pressure value determination means 56: Compression means 58: Acceleration pulse wave correction means Applicant: Korin Electronics Co., Ltd. straight

Claims (1)

[Scope of Claims] Pulse wave detection means for detecting a pulse wave generated from an artery of a living body, and differentiation means for generating an accelerated pulse wave by performing second-order differentiation on the pulse wave detected by the pulse wave detection means. An accelerated pulse wave detection device comprising: a compression means wound around a part of the living body, and a blood pressure value determining means for determining a blood pressure value of the living body using the compression means; An accelerated pulse wave detection device comprising: accelerated pulse wave correction means for correcting the accelerated pulse wave based on the blood pressure value of the living body obtained by the blood pressure value determination means.