JPH01155828A - Pulse wave detector - Google Patents

Abstract

PURPOSE:To rapidly position a pulse wave detection region directly above a blood vessel by detecting the variation of the surface of the body accompanied by the pulsation of a blood vessel in a non-contact state and determining a region where the variation is largest as the pulse wave detection region. CONSTITUTION:In determining the pulse wave detection region to which the pressure sensor 50 of a pulse wave detector 40 must be pressed, a variation detector 42 for detecting the variation of the surface 28 of the body in a non- contact state is moved along the surface 28 of the body. The region directly above the bone artery 30 said to be largest in variation detected by the variation detector 42 is determined as the pulse wave detection region and the pulse wave detector 40 is positioned at this pulse wave detection region.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a pulse wave detection device, and particularly to a pulse wave detection device in which a pulse wave detection site for detecting a pulse wave by pressing a pressure sensor is quickly determined to be directly above a blood vessel. It is related to the device.

PRIOR TECHNOLOGY The pressure waves or vibrations of the blood vessel walls that are generated with the beating of the heart and propagate within the blood vessels are generally called pulse waves, and this pulse wave can be used to determine various things, such as the state of cardiac motion and blood pressure levels. It is known that medical information can be obtained. and,
As a device for detecting such a pulse wave, there is one that detects pressure vibrations of the pulse wave generated from the blood vessels of the human body using a pressure sensor that is pressed against the surface of the human body.

Here, in order to suitably detect a pulse wave, it is desirable that the region on which the pressure sensor is pressed, that is, the pulse wave detection region, be set on the surface of the human body and directly above the blood vessel. Therefore, while moving the pressure sensor in the direction intersecting the blood vessel, pulse waves are detected at multiple locations, and based on the amplitude of the obtained pulse waves, etc., the location directly above the blood vessel is determined as the pulse wave detection location. A pulse wave detection device has been proposed in which a pressure sensor is pressed against the pulse wave detection site to detect the pulse wave. For example, the patent application filed earlier by the applicant in 1982-10
The device described in No. 9594 is one example.

Problems to be Solved by the Invention However, when moving the pressure sensor in a direction that intersects with blood vessels and actually pressing it against the body surface to detect pulse waves at multiple locations, it is difficult to move the pressure sensor into the body. If you try to move it while pressing it against the surface, there is a risk that the body surface or internal tissues may twist or blood vessels may escape, impairing pulse wave detection.

Therefore, when moving the pressure sensor, it is desirable to temporarily separate it from the body surface, but in that case, it takes a long time to move the pressure sensor and to determine the pulse wave detection site. However, this method has the disadvantage of imposing an unnecessary burden on the examinee.

Means for Solving the Problems The present invention has been made against the background of the above circumstances.
The purpose of this is to quickly determine the pulse wave detection site where the pressure sensor is pressed to detect the pulse wave directly above the blood vessel where the pulse wave is to be detected.

In order to achieve this object, the present invention provides a pulse wave detection device that detects pressure vibrations of pulse waves generated from blood vessels of a human body using a pressure sensor pressed against the surface of the human body. (b) a first moving means for moving the variation detecting means on the body surface in a direction intersecting the blood vessel; , (C) detection region determining means for determining, as a pulse wave detection region, a region where the fluctuation of the body surface detected by the fluctuation detection means is largest in the direction intersecting the blood vessel; and (d) determining the detection region. and second moving means for positioning the pressure sensor directly above the pulse wave detection site determined by the means.

Operation and Effects of the Invention In this pulse wave detection device, the fluctuation detection means for non-contact detecting the fluctuation of the body surface accompanying the pulsation of the blood vessel is moved in a direction intersecting the blood vessel by the first moving means. As a result, the fluctuation state of the body surface in the direction intersecting the blood vessel is detected, and the detection region determining means determines the region where the fluctuation is the largest as the pulse wave detection region. The part on the body surface where the degree variation is the largest is the part directly above the blood vessel, and the pulse wave detection part is usually determined to be directly above the blood vessel. Then, by positioning the pressure sensor directly above the pulse wave detection site by the second moving means and pressing against the pulse wave detection site, the pressure vibration of the pulse wave generated from the blood vessel is transmitted to the blood vessel. It will be well detected directly above.

Here, in the present invention, the part of the body surface directly above the blood vessel is determined as the pulse wave detection part by using a fluctuation detection means that detects the fluctuation of the body surface in a non-contact manner. The pulse wave detection site can be determined with high accuracy simply by moving the fluctuation detection means without contacting the body surface, whereas the conventional pressure sensor is moved and pressed one by one on the body surface. Compared to the above, the time required to determine the pulse wave detection site is shortened, and the burden on the subject is reduced.

In addition, when the pressure sensor and the fluctuation detection means are arranged symmetrically about the axis of the mounting shaft arranged substantially perpendicular to the body surface, the first moving means is configured to move its mounting shaft along the body surface, while the second moving means moves its mounting shaft to a position corresponding to the pulse wave detection site and rotates it 1800 times around its axis. Compared to the case where the pressure sensor and the fluctuation detection means are moved independently, the structure and operation of the first and second moving means are simplified.

In addition, as the above-mentioned variation detection means, for example, the phase difference between the reflected light of the light projected onto the body surface and the reference light that is combined with the reflected light through another optical path is determined by the variation of the body surface. The path of reflected light of light projected diagonally to the body surface changes due to changes in the body surface, or Various means can be employed, such as utilizing the fact that the time until the echo of the sound wave is received and the phase difference with the reference ultrasound change depending on changes in the body surface.

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

In FIG. 1, a wrist 14 of a human body is held in a substantially constant posture on a support base 12 of a main body frame 10. The main body frame 10 is also provided with a movable arm 18 having a sensor head 16 at one end. This movable arm 18 is slidably fitted into a guide bush 20 fixed to the main body frame 10, and is configured to be reciprocated by a drive motor 26 via a rack 22 and a pinion 24. Thereby, the sensor head 16 moves directly above the radial artery 30 for which pulse waves are to be detected on the body surface 28 of the wrist 14 in a direction that intersects the radial artery 30 at a substantially right angle. be moved in parallel. That is, the movable arm 18 and the guide bush 20 have a substantially arcuate shape in a direction that intersects the radial artery 30 at a substantially right angle at a portion of the body surface 28 directly above the radial artery 30. As someone who is
The movable arm 18 is formed into a circular arc shape centered on the center of curvature, and the movable arm 18 can be moved along the circular arc shape centered on the center of curvature. These movable arms 18. Guide bush 20. A first moving means includes the drive motor 26 and the like.

The sensor head 16 includes two drive cylinders 32, 34 integrally fixed to one end of the movable arm 18. These drive cylinders 32, 34 are arranged in series in the axial direction, and one mounting shaft 36 is inserted through the axis of the cylinders in a direction substantially perpendicular to the body surface 28. . One drive cylinder 32 is equipped with a rotary piston that can be rotated 1800 times around the axis, although not shown, and is fitted with a spline to the rotary piston so that it cannot rotate relative to the axis. The movably connected mounting shaft 36 is rotated 1800 degrees around the axis from the fluctuation detection phase shown in FIG.
It is designed to be positioned alternatively at two positions with the rotated pulse wave detection phase. In addition, the other drive cylinder 34
is equipped with a piston 38 that is fitted to be rotatable about the axis and is reciprocated in the axial direction. It is designed to be positioned alternatively in two positions: a position and a forward position in which it protrudes toward the lower left in FIG. 1 from that state.

At the tip of the mounting shaft 36, a pulse wave detector 40 and a fluctuation detector 42 are arranged symmetrically with respect to its axis. The pulse wave detector 40 has a pressure chamber 4 in a housing 44.
6 is supplied with pressure fluid, and a pressure sensor 50 held by a diaphragm 48 is pressed against the body surface 28, thereby detecting pressure vibrations of pulse waves generated from the radial artery 30. The pressure sensor 50 includes a strain gauge, a piezoelectric element such as a pressure-sensitive diode, and the like.

Further, the variation detector 42 constitutes a variation detection means, and as shown in FIG. 2, the laser oscillator 52. Lenses 54a, 54b, 54c, half mirror 563 reflecting mirror 58. and an optical sensor 60, the body surface 2
The optical sensor 60 receives the combined light of the reflected laser beam reflected by the reflector 8 and the reflected laser beam reflected by the reflector 58. Since the light intensity of the combined light changes due to the interference of both reflected laser beams, a change in the phase difference thereof, that is, a change in the body surface 28, the state of change in the body surface 28 is detected from this change in light intensity.

For example, the part where the body surface 28 fluctuates the most is the part directly above the radial artery 30, and the light intensity there is
As shown in FIG. 4, it changes significantly at a period of approximately 1 second in synchronization with the pulsation of the radial artery 30. The frequency of the laser beam emitted from the laser oscillator 52 takes into consideration the amount of displacement of the body surface 28 directly above the radial artery 30, and the light intensity of the combined light changes in synchronization with the fluctuation of the body surface 28. It is preset as follows.

Here, the movable arm 18. The first moving device including the guide bush 20, the drive motor 26, etc. is configured such that the fluctuation detector 42 in a state where at least the mounting shaft 36 of the sensor head 16 is positioned in the fluctuation detection phase,
It is configured to travel directly across the radial artery 30. Further, the position of the fluctuation detector 42 in the fluctuation detection phase and the position of the pulse wave detector 40 in the pulse wave detection phase are made to match, and at this time, these detectors 40 and 42 are approximately aligned with respect to the body surface 28. Vertically opposed. - On the other hand, the retracted position of the mounting shaft 36 by the drive cylinder 34 is predetermined so that the fluctuation detector 42 in the fluctuation detection phase is slightly separated from the body surface 28, and the forward position is determined in advance in the pulse wave detection phase. Pressure sensor 50 of the pulse wave detector 40 in
is predetermined so that it can be pressed against the body surface 28 by deformation of the diaphragm 48. diaphragm 48
Since the amount of protrusion of the pressure sensor 50 due to the deformation of the wrist is relatively large, even if the thickness of the wrist 14 differs due to individual differences, it is unlikely that pulse wave detection will become impossible.

The pressure sensor 50 outputs a pulse wave signal S corresponding to a pulse wave.
M is outputted, and is supplied to the control device 62 shown in FIG. 3 through an amplifier and a band-pass filter that passes only the vibration component of the pulse wave. In addition, the optical sensor 60
, an optical signal S corresponding to the optical intensity of the received combined light
O is output and supplied to the control device 62 through an amplifier and a band-pass filter that passes only the vibration component that is substantially the same as the pulsation of the radial motion JIlit 30, that is, the pulsation of the heart.

The control device 62 is composed of a so-called microcomputer or the like, and processes the pulse wave signal SM and the optical signal SO according to a predetermined program, and
Drive signals DM and DCI are sent to drive control devices 64, 66, and 68.
, DC2 to drive the drive motor 26. Controls the actuation of drive cylinders 32, 34, respectively. Further, the pressure sensor 50 is pressed against the body surface 28 by outputting a drive signal DL to the fluid supply device 70 that supplies pressure fluid into the pressure chamber 46 of the pulse wave detector 40 and controlling its operation. At the same time, the pressing force is controlled.

Furthermore, a display signal DD is output to the display/recording device 72,
The pulse wave determined according to the pulse wave signal SM is displayed and recorded.

FIG. 5 is a flowchart illustrating an example of the signal processing logic of the control device f62, and the operation of this embodiment will be described below in accordance with this flowchart.

First, step S1 is executed in a state in which the mounting shaft 36 is positioned in the retracted position at the fluctuation detection phase and the human wrist 14 is held on the support base 12. In this step S1, the motor drive control device 64 receives a drive signal DM.
is output and the drive motor 26 is operated, so that the sensor head 16 is moved on the body surface 28 in a direction intersecting the radial artery 30, and an optical signal SO is output from the optical sensor 60 of the fluctuation detector 42. Loaded. The sensor head 16 is configured to perform a comparison so that when the variation detector 42 passes directly above the radial artery 30, the variation in the body surface 28 accompanying the pulsation of the radial artery 30 can be detected by the variation detector 42. It can be moved continuously at a slow speed or intermittently over small distances. That is, since fluctuations in the body surface 28 due to the pulsation of the radial artery 30 occur at a cycle of about 1 second, in order to detect the fluctuations, a laser beam is projected onto the intertractual part of the body surface 14 for more than 1 second. There is a need. Further, at this time, the fluctuation detector 42 is moved without contacting the body surface 28.

In this way, when the fluctuation state of the body surface 28 in the direction intersecting the radial artery 30 is detected, step S2 is subsequently executed, and the body surface 28 is detected based on the optical signal SO.
Among them, the site with the largest variation is determined as the pulse wave detection site. That is, the variation width D of the light intensity represented by the optical signal SO
(See FIG. 4), or the region where the ratio of the variation width to the light intensity is the largest is determined as the pulse wave detection region. The area directly above the radial artery 30 is where the body surface 28 changes the most, and the area directly above the radial artery 30 is usually determined as the pulse wave detection area. Note that this pulse wave detection site means one point on the body surface 28, but this refers to the position of the sensor head I6 to which the optical signal SO with the largest change in light intensity is supplied, and more specifically, is determined as the rotational phase of the drive motor 26. Of the series of signal processing logic by the control device 6.2, the part that executes this step S2 corresponds to the detection site determination means.

Next, step S3 is executed, and the sensor head 16 is placed at a position corresponding to the pulse wave detection site, that is, on the mounting shaft 3.
6 is maintained at the fluctuation detection phase, the fluctuation detector 42 is moved to a position directly above the pulse wave detection site. Then, step S4 is executed at that position, and the drive signal DCI is output to the cylinder drive control device 66, so that the drive cylinder 32 controls the mounting shaft 3.
6 is rotated 180". As a result, the fluctuation detector 42 and the pulse wave detector 40 are exchanged, and the pulse wave detector 40 is positioned directly above the pulse wave detection site. In this embodiment, , a portion of the series of signal processing logic by the control device 62 that executes steps S3 and 34,
and a drive motor 26° drive cylinder 32 operated according to these steps, and further said movable arm 18.
．． Guide bush 20. The second moving means includes the mounting shaft 36 and the like, and the drive motor 26 and the like also serve as the first moving means. Note that these steps S3 and S4 may be performed at the same time, or step S4 may be performed and then S3 may be performed.

Thereafter, step S5 is executed, and the drive signal DC2 is output to the cylinder drive control device 68, so that the mounting shaft 36 is advanced to the forward position by the drive cylinder 34. Then, step S6 is executed in this state, and the drive signal DL is output to the fluid supply device 70, so that the pressure sensor 50 of the pulse wave detector 40 is positioned on the body surface 28 and directly above the radial artery 30. While being pressed, the pulse wave signal SM output from the pressure sensor 50 is read,
After the pressing force of the pressure sensor 50 is adjusted based on the amplitude, signal strength, etc. of the pulse wave signal SM, the display/recording device 72
The display signal DD is outputted to the pulse wave signal SM, and the pulse wave represented by the pulse wave signal SM is displayed and recorded. Note that, if necessary, it is also possible to automatically diagnose the cardiac activity state etc. based on the detected pulse wave waveform, or to determine the systolic blood pressure value and diastolic blood pressure value from the pulse wave.

Here, in the pulse wave detection device of the present embodiment, when determining the pulse wave detection site where the pressure sensor 50 of the pulse wave detector 40 should be pressed, a fluctuation detector is used to detect fluctuations on the body surface 28 in a non-contact manner. 42 along the body surface 28, the site directly above the radial artery 30, where the variation is greatest, is determined as the pulse wave detection site. Compared to the case where the pressure sensor 50 is pressed against the body surface 28 while moving the device 40, the time required to determine the pulse wave detection site is shortened and the burden on the subject is reduced.

Further, in this embodiment, the pulse wave detector 40 and the fluctuation detector 4
2 are attached to the mounting shaft 36 and the common drive motor 26
At the same time, the position of the pulse wave detector 40 and the fluctuation of the pulse wave detector 40 are changed by rotating the mounting shaft 36 by 1800 rotations by the drive cylinder 32.
Since the position of the pulse wave detector 40 and the fluctuation detector 42 are changed, compared to the case where the pulse wave detector 40 and the fluctuation detector 42 are moved independently, fluctuation detection is required to determine the pulse wave detection site. There is an advantage that the configuration and operation for moving the device 42 in a direction intersecting the radial artery 30 and positioning the pulse wave detector 40 directly above the pulse wave detection site are simplified.

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

For example, in the embodiment described above, the body surface 28 is assumed to have an arc shape and the sensor head 16 is moved along the arc shape. Even if the gap changes, it is sufficiently possible to detect changes in the body surface 28, so the sensor head 1
It is also possible to detect fluctuations in the body surface 28 while moving the body 6 in a straight line.

Further, in the embodiment, the pulse wave detector 40 and the fluctuation detector 42 are attached to the mounting shaft 36, and the mounting shaft 36 is
Although the position is changed by rotating 800 degrees, it is possible to provide these detectors 40 and 42 on separate moving members and move them independently, or instead of rotating the mounting shaft 36. It is also possible to change their positions by means of the drive motor 26.

In the embodiment described above, the mounting shaft 36 is rotated and moved forward by the drive cylinders 32 and 34.

Although it is designed to move backward, various other means can be used, such as rotating it with an electric motor or moving it forward and backward using a feed screw.

In addition, the pulse wave detector 40 of the above embodiment is configured to press the pressure sensor 50 against the body surface 28 by supplying pressure fluid into the pressure chamber 46. .

It is also possible to press using a solenoid or the like.

Further, although the variation detector 42 in the above embodiment detects variations in the body surface 28 by using interference of laser light, other variation detection means such as one using ultrasonic waves may be used. is also possible.

In addition, in the embodiment described above, the region with the largest variation is determined based on the range of variation in light intensity, but depending on the frequency of the laser beam, the number of interference fringes due to variation on the body surface 28 may vary depending on the frequency of the laser beam.
In other words, it is also possible to determine the region with the largest variation based on the number of changes in light intensity.

Further, in the embodiment described above, a pulse wave detection device that detects pulse waves from the radial artery 30 has been described, but the present invention can be similarly applied when detecting pulse waves from other arteries such as the carotid artery or veins that have pressure oscillations. can be applied to

Although other examples are not provided, the present invention can be implemented with various modifications and improvements based on the knowledge of those skilled in the art.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view illustrating a pulse wave detection device that is an embodiment of the present invention. FIG. 2 is a block diagram of the variation detector in FIG. 1. FIG. 3 is a block diagram showing the control system of the device shown in FIG. FIG. 4 is a diagram showing changes in the intensity of the optical signal output from the fluctuation detector of FIG. 2. FIG. 5 is a flowchart illustrating the operation of the apparatus of FIG. 18: Movable arm 20 guide bush 26: Drive motor 28: Body surface 30: Radial artery (blood vessel) 32: Drive cylinder 36: Mounting shaft 42: Fluctuation detector (fluctuation detection means) 50: Pressure sensor 62: Control Device step S2:
Detection site determining means step S3. S4: Second transportation means applicant Korin Electronics Co., Ltd. Figure 1 Figure 2 Figure 1, Figure 4 Time 9tP Figure 5

Claims (2)

[Claims] (1) A pulse wave detection device that detects pressure vibrations of pulse waves generated from blood vessels of a human body using a pressure sensor pressed against the body surface of the human body, which detects fluctuations in the body surface due to pulsations of the blood vessels. a fluctuation detection means for detecting non-contact; a first moving means for moving the fluctuation detection means on the body surface in a direction intersecting the blood vessel; Detection site determining means for determining a site where the body surface has the greatest variation as a pulse wave detection site; and positioning the pressure sensor directly above the pulse wave detection site determined by the detection site determining means. 1. A pulse wave detection device comprising: 2. a moving means. (2) The pressure sensor and the fluctuation detection means are arranged symmetrically about the axis of the mounting shaft, which is arranged substantially perpendicular to the body surface, and the first
The moving means moves the mounting shaft along the body surface, and the second moving means moves the mounting shaft to a position corresponding to the pulse wave detection site and rotates the mounting shaft 1800 degrees around the axis. The pulse wave detection device according to claim 1, which rotates.