JPH01192334A - Pulse wave detecting device - Google Patents

Abstract

PURPOSE:To pick up a pulse wave shape with high accuracy without needing a comparatively correct positioning on an artery by having a fluid container filled with the fluid in the internal part and an oscillation sensor to provide in the fluid container, detect the oscillation of a bottom wall with the non-contact and output a signal to show the pulsatory motion of the bottom wall. CONSTITUTION:A CPU determines a blood pressure value based on a pulse wave signal SM, displays it at a blood pressure indicator 38 and a waveform indicator 40 displays the pulse wave. The upper peak value of the pulse wave corresponds to the maximum blood pressure value and the lower peak value of the pulse wave corresponds to the minimum blood pressure value respectively, and therefore, the blood pressure value is determined based on an actual peak value from the corresponding relations obtained beforehand. The pulse wave shape displayed in the waveform indicator 40 displays the artery pressure and therefore, it is used as various pieces of medical information. As the above, when a flexible bottom wall 18 is suitably pressurized onto the artery 12, it can be oscillated corresponding to the pulsatory motion of the artery 12, the oscillation is detected with non-contact by an ultrasonic type oscillation sensor 22, and therefore, the highly accurate pulse wave shape is obtained without needing the correct positioning on the artery 12.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a device for detecting pulse waves generated in blood vessels in synchronization with the heartbeat of a living body.

Prior Art Since the pulse waveform of a living body is closely related to the state of the circulatory system, it has been considered to collect medical information by detecting the pulse wave generated in the blood vessels of the living body. For example, Japanese Patent Application Laid-Open No. 59-180618 discloses a technique for detecting the carotid artery wave shape, which is closely related to the state of arteriosclerosis. Further, Japanese Patent Laid-Open No. 1078.09/1989, previously filed by the applicant, discloses a technique for detecting radial artery waves that are closely related to blood pressure values.

Problems to be Solved by the Invention Incidentally, the conventional pulse wave detecting device as described above is configured to press the artery with a moderate pressing force by a pressing member, and uses an electric signal converter such as a strain gauge or a piezoelectric element. Pulse waves are detected by converting the vibrations of the pressing member itself or the vibrations transmitted to the pressing member into electrical signals using an element, but it is difficult to accurately position the pressing member over the center of the artery. For this reason, the conventional devices described above use a pressing member larger than the diameter of the artery, or arrange a plurality of extremely small piezoelectric elements on the pressing surface.

However, devices in which the pressing member itself is larger in diameter than the artery have the disadvantage that the shape of the pulse wave changes as the relative position of the pressing member with respect to the artery changes. On the other hand, with a pulse wave detection device in which extremely small piezoelectric elements are arranged on a pressing surface, a relatively accurate pulse wave can be obtained by selecting a piezoelectric element located directly above the artery.
It has the disadvantage of being expensive because it requires advanced integration technology.

Means for Solving the Problems The present invention has been made against the background of the above circumstances.
The purpose is to provide a pulse wave detection device with a simple structure that can collect a highly accurate pulse wave shape without requiring relatively accurate positioning on an artery.

In order to achieve such an object, the gist of the present invention is to provide a pulse wave detection device that detects the pulse wave of a living body by being pressed onto an artery located near the surface of the living body, the device comprising (a) ) A fluid container, which is provided in the fluid container and includes at least a bottom wall that is made of a flexible membrane and is brought into close contact with the surface of the living body, and is filled with fluid; The present invention includes a vibration sensor that detects vibrations of the wall in a non-contact manner and outputs a signal representing the pulsation of the bottom wall.

Operation and Effects of the Invention In this manner, when the bottom wall of a relatively large fluid container positioned above the artery of a living body is pressed against the artery, the flexible bottom wall will not respond to the pulsation of the artery wall. It is made to vibrate accordingly. A vibration sensor provided within the fluid container detects the vibration of the bottom wall in a non-contact manner. The electrical signal output from this vibration sensor relatively accurately corresponds to the pulse wave shape of the artery. Therefore, a highly accurate pulse waveform can be obtained with a relatively simple structure without requiring accurate positioning on the artery.

Here, the fluid may be not only an incompressible fluid such as water or oil, but also a compressible fluid such as air. The fluid is preferably changed and maintained at a pressure such that the amplitude of the signal is maximized.

Moreover, an ultrasonic vibration sensor that emits ultrasonic waves toward the bottom wall and detects pulsations of the bottom wall based on the Doppler shift of reflected waves from the ultrasonic waves is preferably employed as the vibration sensor. In addition, the vibration sensor includes an optical vibration sensor that emits light toward the bottom wall and detects the pulsation of the bottom wall based on the intensity or phase change of the reflected wave, and an optical vibration sensor that electromagnetically detects the vibration of the bottom wall. Other types of sensors may also be used, such as electromagnetic vibration sensors. In addition, the above-mentioned ultrasonic vibration sensor may consist of one ultrasonic generation element or reflected wave detection element, or may consist of one element and a plurality of other elements in order to obtain a highly accurate pulse wave signal. or a combination of both. In addition, in optical vibration sensors, the light source such as a semiconductor laser chip that emits light and the light receiving element such as a photodiode or phototransistor are not only a pair, but also one in order to detect a highly accurate pulse wave signal. A plurality of the other or a plurality of both may be arranged.

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

In FIG. 1, a pulse wave detection probe 14 is fixedly positioned by a support band 15 on the surface of a living body 10, directly above an artery 12 located near the skin. The pulse wave detection probe 14 includes a fluid container 20 consisting of a relatively rigid container-shaped main body 16 with an open lower surface and a bottom wall 18 provided to seal the bottom surface of the main body 16 in a fluid-tight manner. The bottom wall 1 is provided in the fluid container 20.
A vibration sensor 22 for obtaining a pulse wave signal SM corresponding to the pulsation of the bottom wall 18 by non-contactly detecting the displacement of the bottom wall 18.
It is equipped with

The bottom wall 18 is a flexible single-layer film made of synthetic rubber, synthetic resin, or the like, or a multilayer structure including these, and is designed to vibrate as the artery 12 expands and contracts in synchronization with the heartbeat. It has become.

Further, the vibration sensor 22 includes a pair of ultrasonic oscillating element 24 and an ultrasonic receiving element 26 that are fixed to a surface of the earthen wall of the main body 16 that faces the bottom wall 18 . The ultrasonic oscillating element 24 is supplied with a drive signal of a constant frequency from an oscillator 28, and the ultrasonic receiving element 26 detects reflected waves from the bottom wall 18.
The output signal is amplified by an amplifier 30, and then a phase detection circuit 32 continuously detects a change in phase. The phase of the reflected wave is generated by Doppler shift, and the phase change of the reflected wave corresponds to the vibration motion of the bottom wall 18. Therefore, the phase detection circuit 32 outputs a pulse wave signal SM indicating the pulsation of the artery 12.

The pulse wave signal SM is then converted into a digital signal by the A/D converter 34 and then supplied to the microcomputer 36.

The microcomputer 36 includes a CPU (not shown), an RA
Equipped with M, ROM, I10 interface, etc.
The CPU uses the storage function of the RAM and inputs the input signal (pulse wave signal SM) according to the program stored in the ROM in advance.
is processed, and the fluid pressure within the fluid container 20 is regulated. That is, the microcomputer 36 operates the pressure regulating valve 42 in response to the operation of a start push button (not shown) to supply the pressure of the fluid pressure generator 44 into the fluid container 20, and also controls the magnitude of the pulse wave signal SM, such as the amplitude. , signal power, etc., and detect whether the magnitude of the pulse wave signal SM is saturated or not. When the magnitude of the pulse wave signal SM is saturated, the pressure regulating valve 42 is operated by feedback control so that the pressure is maintained. Further, the CPU determines a blood pressure value based on the pulse wave signal SM and causes the blood pressure display 38 to display the determined blood pressure value, and the waveform display 40
display the pulse wave. The upper peak value of the pulse wave is the systolic blood pressure value,
Since the lower peak values of the pulse wave each correspond to the diastolic blood pressure value, the blood pressure value is determined based on the actual peak value from the correspondence relationship determined in advance. Furthermore, since the pulse wave shape displayed on the waveform display 40 as described above represents arterial pressure, it is utilized as various medical information.

However, one of waveform display 40 and blood pressure display 38 may be removed.

In the device configured as described above, when the flexible bottom wall 18 is appropriately pressed onto the artery 12, it is vibrated in response to the pulsation of the artery 12, and the vibration is transmitted to the ultrasonic wave. Since it is detected by the vibration sensor 22 without contact, accurate positioning on the artery 12 is not required (a highly accurate pulse waveform can be obtained with a relatively simple structure).

Next, another embodiment of the present invention will be described. In the following description, parts common to those in the above-mentioned embodiment will be denoted by the same reference numerals, and the description thereof will be omitted.

In FIG. 2, vibrations of the bottom wall 18 are detected using laser Doppler. That is, light having a predetermined beat frequency is emitted from the laser light source 46, and reflected light from the bottom wall 18 is detected by the light receiving sensor 48. In this embodiment, as in the above-described embodiment, a phase change corresponding to the vibration of the bottom wall 18 occurs in the reflected light, so the phase change in the signal output from the light receiving sensor 48 is detected by the phase detection circuit 32. and output as a pulse wave signal SM.

In the embodiment shown in FIG. 3, the inner wall surface of the bottom wall 18 is provided with a magnetic layer 52 such as an iron-chromium thin film. An electromagnetic solenoid 50 is provided within the main body 16 and outputs an induced signal in response to a change in the gap with the bottom wall 18.

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

For example, in the embodiment described above, the internal pressure of the fluid container 2'0 is regulated by the pressure regulating valve 42, but the fluid container 20 is sealed and the tension of the support band 15 is adjusted. It may be configured, or a certain pulse wave collection function can be obtained even without such an adjustment mechanism.

Further, in the above embodiment, even if the fluid supplied into the fluid container 20 is an incompressible fluid such as water or oil,
Further, it may be a compressible fluid such as air or carbon dioxide.

Further, since it is sufficient that at least the bottom wall 18 portion is flexible, the outer circumferential wall of the fluid container 20 may also be flexible.

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 diagram illustrating the configuration of an embodiment of the present invention. FIG. 2 and FIG. 3 are diagrams each illustrating main parts in other embodiments of the present invention. 10: Living body 12: Artery 18: Bottom wall 20; Fluid container 22: Vibration sensor (ultrasonic vibration sensor) 50: Electromagnetic pink-up solenoid (electromagnetic vibration sensor)

Claims (1)

[Scope of Claims] A pulse wave detection device that detects a pulse wave of a living body by being pressed onto an artery located near the surface of the living body, the device comprising: a flexible membrane; A fluid container is provided with at least a bottom wall that is brought into close contact with the surface of a living body and is filled with fluid; A pulse wave detection device comprising: a vibration sensor that outputs a signal representing pulsation;