JPH1156799A - Carotid arterial pressure wave detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carotid arterial pressure wave detecting device capable of easily detecting the carotid arterial pressure wave. SOLUTION: In this device, a carotid arterial pressure wave signal SA showing the pressure in a carotid artery is generated by deducting DC components (DCa+DCc)/2 of pressure signals SPa, SPc outputted from pressure sensors 58a, 58c placed apart from the carotid artery from a pressure signal SPb outputted from a pressure sensor 58b placed right above the carotid artery among the plural pressure sensors 58a, 58b, 58c by carotid arterial pressure wave signal generating means (an arithmetic and control circuit 82) in a state where a housing is mounted on a neck of a living body such that the plural pressure sensors 58a, 58b, 58c are arranged in a direction crossing the carotid artery by a holding device functioning as a housing mounting device. Thereby, the carotid arterial pressure wave signal SA showing the pressure in the carotid artery relatively precisely can be easily detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carotid artery pressure wave detecting device for detecting a carotid artery pressure wave representing a pressure in a carotid artery.

[0002]

2. Description of the Related Art The blood pressure waveform or pressure wave in the carotid artery is
Since it is a pressure waveform of blood output from the aorta and supplied to the brain, it is medically important biological information. Such a carotid artery pressure wave is directly detected by inserting a catheter into an artery.

[0003]

However, when a catheter is inserted into an artery and a carotid artery pressure wave is directly detected as described above, an incision or insertion of a catheter by a surgeon is required. The carotid artery pressure wave could not be easily detected.

[0004] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a carotid artery pressure wave detecting device capable of easily detecting a carotid artery pressure wave.

[0005]

SUMMARY OF THE INVENTION To achieve the above object, the gist of the present invention is to provide a carotid artery pressure wave detecting device for detecting a pressure wave in the carotid artery of a living body by being pressed against the neck. (A) having a pressing surface pressed against the neck, a plurality of pressure sensors for detecting the pressure on the pressing surface, and (b) the plurality of pressure sensors from the diameter of the carotid artery (C) mounting the housing on the neck of the living body such that the arrangement direction of the plurality of pressure sensors is in a direction transverse to the carotid artery. And (d) outputting from a pressure sensor located apart from the carotid artery from a first pressure signal output from a pressure sensor located directly above the carotid artery of the pressure sensors. DC component of the second pressure signal By then pulling the carotid pressure wave signal generating means for generating the carotid pressure wave signal representative of the pressure in the carotid artery is to contain.

[0006]

According to the present invention, the carotid artery is mounted in a state in which the housing is mounted on the neck of the living body by the housing mounting device such that the arrangement direction of the plurality of pressure sensors is in the direction crossing the carotid artery. The pressure wave signal generating means outputs a first pressure signal output from a pressure sensor located directly above the carotid artery among the plurality of pressure sensors, to a first pressure signal output from a pressure sensor located apart from the carotid artery. By subtracting the DC component of the two pressure signals, a carotid artery pressure wave signal representing the pressure in the carotid artery is generated. Since the carotid artery pressure wave signal is obtained by subtracting the DC component of the second pressure signal corresponding to the pressing force applied from the housing to the pressure sensor from the first pressure signal, the pressure in the carotid artery is calculated. Since the value represents a relatively accurate value, the carotid artery pressure wave can be easily detected by obtaining the carotid artery pressure wave signal.

[0007]

Here, preferably, the housing holds three or more pressure sensors.
In this way, pressing the carotid artery can be easily performed without skill.

Preferably, the DC component of the second pressure signal is a second pressure signal output from a pair of pressure sensors located on both sides of a pressure sensor located directly above the carotid artery. Is the average value of the DC component of. In this way, even if there is a bias in the pressing force applied from the housing to the pressure sensor, there is an advantage that the bias can be suitably eliminated.

Preferably, the pressure sensor generates an elastic deformation member that generates a pressing reaction force from the skin acting on the pressing surface, that is, a distortion of a magnitude corresponding to the pressure, and generates the elastic deformation member. A strain sensor for detecting strain, and outputting a signal representing the magnitude of the strain detected by the strain sensor as a pressure signal.

[0010] Preferably, the pressure sensor has a pair of side surfaces whose distance becomes smaller as the pressure sensor becomes farther from the pressing surface, and the housing has a receiving hole open at one end and a receiving hole. A pair of opposed inclined surfaces formed on a side wall surface of which the distance from each other increases from the inside to the outside, and a side surface of the plurality of pressure sensors located at both ends and the pair of inclined surfaces A surface is slidably contacted with each other, and a pair of side surfaces is provided such that a distance between them increases toward the inside (bottom) side of the accommodation hole. The pair of side surfaces is provided so as to be movable in a direction orthogonal to the pressing direction. A lateral moving member slidably in contact with a side surface of the pressure sensor holds the plurality of pressure sensors in a state interposed between the pressure sensors. If you do this,
Since the tips of the plurality of pressure sensors are located at the protruding positions according to the shape of the neck, there is an advantage that the pressing conditions thereof are stable.

Preferably, the housing has a pair of side walls sandwiching the plurality of pressure sensors and a laterally moving member interposed therebetween, and the laterally moving member is orthogonal to the pressing direction. And a linear guide hole formed in a side wall thereof for guiding in the direction of movement. The above-mentioned lateral moving member is provided with an engagement projection which engages with the guide hole. . This has the advantage that the carotid artery pressure wave detection device is relatively small.

Preferably, the carotid artery wave detecting device is curved in one plane as a whole to grip the neck of the living body, and is urged in a diameter decreasing direction by an elastic restoring force. A gripping device attached to one end, and the housing is arranged at one end of the gripping device.
It is possible to swing around a swing center axis located inside the gripping device in the one plane and perpendicular to the one plane,
A swing connection device for connecting the housing and one end of the gripping device. According to this configuration, since the housing and one end of the gripping device are swingably connected by the swing connection device, the unevenness of the surface of the neck is complicated and easily changed. Also, the pressure condition of the pressure sensor on the carotid artery is further stabilized. In addition, the housing and one end of the holding device can be swung about a swing center axis located inside the holding device in a curved plane of the holding device and perpendicular to the one plane. Because of the connection, it is possible to easily follow a change in the uneven shape on the surface of the neck, and there is an advantage that the pressing condition is hard to change.

Preferably, the swing coupling device is formed on an outer wall surface of a side wall of the housing, and a pair of partial outer peripheral surfaces centered on the swing center axis, and one end of the gripping device. And a pair of partial inner peripheral surfaces formed at the branch and slidingly contacting the pair of partial outer peripheral surfaces. In this case, there is an advantage that the swing connection device is easily configured.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a carotid artery pressure wave detecting device 10 according to an embodiment of the present invention will be described in detail with reference to the drawings. 1 and 2 are views for explaining the mechanical configuration of the carotid artery pressure wave detection device 10. FIG.

In FIG. 1 and FIG. 2, a carotid artery pressure wave detecting device 10 is curved in one plane as a whole for grasping the neck of a living body, and is urged in a diameter decreasing direction by an elastic restoring force. 12, a pulse wave detection probe 14 attached to one end thereof, and a pulse wave detection probe 14
Is located inside the gripping device 12 in the one plane with respect to one end of the gripping device 12 and is capable of swinging about a swing center axis C perpendicular to the one plane.
2 and a rocking connection device 16 for rockingly connecting the pulse wave detection probe 14 to each other. The above gripping device 1
2 is a plurality of pressure sensors 58a, 58b, 58
The housing 56 for accommodating the pressure sensors 58 described later so that the arrangement direction of the c
Functions as a housing mounting device for mounting the to the neck of a living body. FIG. 3 shows that the pressure sensors 58a, 58b, 58c housed in the housing 58 in a one-way arrangement by the gripping device 12
Is shown in a state where it is pressed in a state in which it is crossed.

The gripping device 12 has a relatively rigid first curved plate made of a synthetic resin or metal plate.
An arm 20, one end 22 having relatively high rigidity and one end rotatably connected to the first arm 20, and an elastically deformable leaf spring material that extends from the one end 22 and curves. And a second arm 26 comprising the other end 24. The other end of the first arm 20 and the second
The first arm 2 is connected to one end 22 of the arm 26 by a pin 28 so as to be rotatable around the pin 28.
0 and the first arm 2 by the coil spring 30 stretched between the other end of the second arm 26 and the one end 22 of the second arm 26.
The zero and second arms 26 are urged in a direction approaching each other, in a direction in which they are closed, or in a diameter decreasing direction of a circle formed by the mutually curved shapes of the first arm 20 and the second arm 26.

One end of the first arm 20, that is, a branch portion, is branched in a forked shape, and the pulse wave detection probe 14 is swingably connected between the two forked ends. At the forked end of the first arm 20,
A partial inner peripheral surface 34 centered on the swing center axis C is formed, and a stepped surface of a convex portion 36 protruding from the front surface and the back surface of the pulse wave detection probe 14, respectively. A pair of partial outer peripheral surfaces 38 that are in sliding contact with the peripheral surface 34 are formed, and the pulse wave detection probe 14 is connected to one end of the first arm 20 so as to be able to swing around a swing center axis C. Have been. Therefore, the forked end of the first arm 20 on which the partial inner peripheral surface 34 is formed and the convex portion 36 on which the partial outer peripheral surface 38 is formed.
Constitute the swing connection device 16. A groove 40 having a partial outer peripheral surface 38 as a bottom surface is formed on the convex portion 36, and an arc-shaped groove 42 is formed on an inner wall surface of the groove 40. Since the arc-shaped protrusion 44 formed along the partial inner peripheral surface 34 in the portion is fitted in the arc-shaped groove 42,
The drop of the pulse wave detection probe 14 from the first arm 20 is prevented. The partial outer peripheral surface 38, the arc-shaped groove 42, and the arc-shaped projection 44 are circular arcs centered on the swing center axis C, similarly to the partial inner peripheral surface 34.

As shown in detail in FIG. 2, the pulse wave detecting probe 14 has a main body 50 having a U-shaped cross section and the convex portion 3.
6 and a pair of side walls 52 fixed to the front and back of the main body 50
And a housing 56 having a receiving hole 54 formed at one end (the upper end in FIG. 2) on the inner peripheral side. The plurality of (three in this embodiment) pressure sensors 58a, 58b, and 58c arranged in parallel, and the lateral moving member 60 interposed between the pressure sensors 58,
Is held by the housing 56. The swing center axis C is positioned substantially at the center of the carotid artery when worn, so that the three pressure sensor members 58a,
8b and 58c, which are located at the center, are located substantially on the center line and near the center of the pressing surface 64.

The pressure sensors 58a, 58b, 58c
Includes a pressing surface 64 provided with a protrusion 62 pressed toward the carotid artery, and a pair of side surfaces 66 whose distance decreases as the distance from the pressing surface 64 increases.
It is housed in the housing hole 54 with its four end portions exposed. The pressure sensors 58a, 58b, and 58c are made of a metal that generates a pressing reaction force from the epidermis of the carotid artery acting on the pressing surface 64, that is, a strain corresponding to the pressure, by being brought into contact with the protrusion 62. An elastically deformable member 63 such as a thin plate, and a semiconductor strain gauge 65 provided on the elastically deformable member 63 and detecting a strain generated in the elastically deformable member 63, and a signal representing the magnitude of the strain detected by the semiconductor strain age 65 is provided. Output as pressure signal. The pressure signals SPa, SPb, SPc detected by the pressure sensors 58a, 58b, 58c are supplied to a measurement circuit 69 described later via a lead wire 68.

The main body 50 of the housing 56 is formed with a pair of inclined surfaces 70 which are opposed to the side surfaces 66 of the plurality of pressure sensors 58 arranged in parallel and which are in sliding contact with the side surfaces 66. Further, a plurality of pressure sensors 5
8a, 58b, and 58c, a pair of side surfaces 72 are formed on the lateral moving member 60, the side surfaces 72 of which are spaced apart from each other toward the inside of the accommodation hole 54. The pressure sensor 58 is in sliding contact with a pair of side surfaces 66.

A plurality of pressure sensors 58 in the receiving hole 54
a, 58b, 58c and a pair of side walls 52 sandwiching the lateral moving member 60 interposed therebetween have linear guides for guiding the lateral moving member 60 in the lateral direction orthogonal to the pressing direction. A hole 74 is formed. The lateral moving member 60 is provided with a small-diameter roller 76 that is engaged with the guide hole 74 and guided by the guide hole 74. Thus, the lateral moving member 60 cannot move in the pressing direction and can move in the lateral direction perpendicular thereto. In this embodiment, the small-diameter roller 76 functions as an engagement projection.

FIG. 4 is a block diagram for explaining a main part of the electrical configuration of the measuring circuit 69. In the figure, pressure signals SPa, SPb, SPc output from three pressure sensors 58a, 58b, 58c, respectively, are supplied to an arithmetic and control circuit 82 via an A / D converter 80. The arithmetic control circuit 82 includes a CPU 84, a ROM 86, a RAM 8
8. A so-called microcomputer having an output interface 90, etc., the CPU 84 processes an input signal according to a program stored in the ROM 86 in advance while utilizing the storage function of the RAM 88, and outputs a carotid artery pressure wave from the output interface 90 to the cervix. The arterial pressure wave signal SA is output to the display 92 or another device (not shown).
In step, the waveform of the carotid artery pressure wave signal SA is displayed.

The arithmetic and control circuit 82 calculates the carotid artery 18 from the pressure signal SPb output from the central pressure sensor 58b located just above the carotid artery 18 among the three pressure sensors 58a, 58b and 58c, for example. Are subtracted from the DC components DCa, DCc of the pressure signals SPa, SPc output from the pressure sensors 58a, 58c positioned at a distance from the pressure sensor 58a, 58c, or their average value (DCa + DCc) / 2, to indicate the pressure in the carotid artery. An arterial pressure wave signal SA is generated. Thus, the arithmetic and control circuit 82 functions as a carotid artery pressure wave signal generating means.

The three pressure sensors 58a, 58b, 5
8c output pressure signals SPa, SPb, SPc
Shows a waveform as shown in FIG. 5, for example.
DC components DCa, DCc of the pressure signals SPa, SPc
Is a magnitude obtained by removing the pulsation (AC) component from the pressure signals SPa and SPc, for example, a minimum value (low peak value) or a moving average value.

FIG. 6 is a flowchart showing an example of the control operation of the arithmetic and control circuit 82 and explaining the main part thereof. In FIG. 6, in step (hereinafter, step is omitted) S1, pressure signals SPa, SPb, SPc output from pressure sensors 58a, 58b, 58c are read. Next, S2 corresponding to the carotid artery pressure wave signal generating means
Then, the average value (DCa + DCc) / 2 of the DC components DCa and DCc of the pressure signals SPa and SPc is obtained from the pressure signal SPb.
Is subtracted, a carotid artery pressure wave signal SA representing the pressure in the carotid artery is calculated. Then, in S3, S2
Is output, and the waveform of the carotid artery pressure wave signal SA representing the pressure wave in the carotid artery 18 is displayed on the display 92 as shown in FIG.

As described above, according to the present embodiment, the arrangement direction of the plurality of pressure sensors 58a, 58b, 58c is set to be the direction traversing the carotid artery 18 by the gripping device 12 functioning as the housing mounting device. In a state where the housing 56 is mounted on the neck of the living body, the carotid artery pressure wave signal generating means (arithmetic control circuit 82, S2) causes the carotid artery 18 out of the plurality of pressure sensors 58a, 58b, 58c.
From the pressure signal SPb output from the pressure sensor 58b located directly above the pressure sensor SP output from the pressure sensors 58a and 58c located at a distance from the carotid artery 18.
a, the carotid artery pressure wave signal SA representing the pressure in the carotid artery 18 is generated by subtracting the DC component (DCa + DCc) / 2 of SPc, so that the carotid artery representing the pressure in the carotid artery 18 relatively accurately The pressure wave signal SA can be easily detected.

According to the present embodiment, the housing 56
Since three pressure sensors 58a, 58b, 58c are held in a state arranged in one direction, the carotid artery 1
Pressing 8 can easily be done without skill.

Further, according to the present embodiment, the DC signals of the pressure signals SPa and SPc output from the pair of pressure sensors 58a and 58c located on both sides of the pressure sensor 58b located just above the carotid artery 18 respectively. Since the average value (DCa + DCc) / 2 is used as a component, even if there is a bias in the pressing force applied from the housing 56 to the pressure sensors 58a, 58b, 58c, there is an advantage that the bias is preferably eliminated. is there.

Further, according to the present embodiment, the pressure sensor 58
a, 58b, and 58c detect an elastic deformation member 63 that generates a pressing reaction force from the skin acting on the pressing surface 64, that is, a distortion that has a magnitude corresponding to the pressure, and a distortion that occurs in the elastic deformation member 63. A semiconductor strain gauge 64;
Since a signal indicating the magnitude of the strain detected by the strain gauge 64 is output as a pressure signal, there is an advantage that the configuration is simplified.

Further, according to the carotid artery wave detecting device 10 of the present embodiment, a plurality of pressure sensors 58a,
8b and 58c, a lateral moving member 60 provided to be movable in a lateral direction perpendicular to the pressing direction is interposed, and a pair of side surfaces 72 of the lateral moving member 60 are connected to the pressure sensors 58a and 58c.
Since it is slid on the side surface 66 of 58b, 58c,
When the carotid artery wave detection device 10 is attached to the neck and the pulse wave detection probe 14 is pressed against the neck surface, the plurality of pressure sensors 58a, 58b, 58c cause the pressure on the pressing surface 64 to be equal. The moving position in the pressing direction is determined. As a result, the carotid artery is pressed by the pressing surfaces of the plurality of pressing direction moving members 58 arranged in a direction intersecting with the carotid artery, so that the unevenness of the surface of the neck is complicated and easily changed. Nevertheless, it is possible to easily follow a change in the uneven shape of the neck surface, and the conditions for pressing the pressure sensors 58a, 58b, 58c against the carotid artery are suitably stabilized.

Further, according to the present embodiment, the housing 56 includes a plurality of pressure sensors 58a, 58b, 58c and a pair of side walls 52 sandwiching a lateral moving member 60 interposed therebetween. And a linear guide hole 74 formed in the side wall 52 for guiding the lateral moving member 60 in the lateral direction orthogonal to the pressing direction. The provision of the small-diameter roller 76 that engages with the hole 74 has the advantage that the carotid artery wave detection device 10 is relatively small.

Further, according to the present embodiment, the carotid artery wave detecting device 10 is curved as a whole in one plane to grip the neck of a living body, and is urged in the diameter reducing direction by an elastic restoring force. A gripping device 12 having the housing mounted on one end thereof, and a housing 56 pivoting with respect to one end of the gripping device 12 within the above-described plane and inside the gripping device 12 and perpendicular to the one plane. Since the swing connection device 16 that connects the housing 56 and one end of the holding device 12 is provided so as to be able to swing around the central axis C, the housing 56 and one end of the holding device 12 are Because it is swingably connected by the dynamic connecting device 16,
Even if the uneven shape of the surface of the neck is complicated and easily changed, the pressing condition of the pressing direction moving member against the carotid artery is further stabilized. In addition, the housing 56 and one end of the gripping device 12 are located inside the gripping device 12 within a curved plane of the gripping device 12 and capable of swinging about a swing center axis C perpendicular to the plane. Are swingably connected to each other, so that they can easily follow a change in the uneven shape of the surface of the neck portion, and there is an advantage that the pressing condition is hard to change.

The swing connection device 16 of this embodiment is formed on the outer wall surface of the side wall 52 of the housing 56, respectively.
A pair of partial outer peripheral surfaces 38 centered on the swing center axis C
And a bifurcated branch formed at one end of the gripping device 12, and a pair of partial inner peripheral surfaces 34 formed at the bifurcation and slidingly contacting the pair of partial outer peripheral surfaces 38. There is an advantage that the swing connection device 16 is simply configured.

While one embodiment of the present invention has been described with reference to the drawings, the present invention can be applied to other embodiments.

For example, the pressure sensor 58 of the above-described embodiment
Each of a, 58b, and 58c includes the elastic deformation member 63 and the strain gauge 64 that detects the distortion thereof. However, a piezoelectric ceramic plate may be disposed instead.

Further, the swing connection device 16 of the above-described embodiment is used.
May be a connecting device having a universal joint type degree of freedom.

In addition, the present invention can be variously modified without departing from the gist thereof.

[Brief description of the drawings]

FIG. 1 is a front view illustrating a mechanical configuration of a carotid artery pressure wave detection device according to an embodiment of the present invention.

FIG. 2 is an enlarged view, partially cut away, for explaining the configuration of the pulse wave detection probe of the embodiment of FIG.

FIG. 3 is a diagram illustrating a position where the pressure sensor presses the carotid artery when the carotid artery pressure wave detecting device of FIG. 1 is attached to a living body.

FIG. 4 is a block diagram illustrating an electrical configuration of the carotid artery pressure wave detection device according to the embodiment of FIG. 1;

FIG. 5 shows a carotid artery pressure wave detection device according to the embodiment of FIG.
FIG. 3 is a diagram illustrating a pressure signal output from each pressure sensor.

FIG. 6 is a flowchart illustrating a main part of a control operation of an arithmetic and control circuit of the carotid artery pressure wave detecting device in the embodiment of FIG. 1;

FIG. 7 is a diagram showing a carotid artery pressure wave signal output by the control operation of the arithmetic and control circuit of the carotid artery pressure wave detecting device in the embodiment of FIG.

[Description of sign]

 10: Carotid artery pressure wave detection device 12: Grasping device (housing mounting device) 18: Carotid artery 56: Housing 58: Pressure sensor 64: Pressing surface SPb: First pressure signal SPa, SPc: Second pressure signal S2: Carotid artery pressure wave Signal generation means

Claims (1)

[Claims] 1. A carotid artery pressure wave detecting device for detecting a pressure wave in a carotid artery of a living body by being pressed against the neck of the living body, comprising a pressing surface pressed by the neck, A plurality of pressure sensors for detecting the pressure in the housing; a housing for holding the plurality of pressure sensors in a state of being arranged in one direction at intervals larger than the diameter of the carotid artery; and a direction in which the plurality of pressure sensors are arranged. A housing mounting device for mounting the housing on the neck of the living body so as to be in a direction crossing the carotid artery; and a pressure sensor output from a pressure sensor located directly above the carotid artery among the pressure sensors. A carotid artery pressure wave that generates a carotid artery pressure wave signal representing the pressure in the carotid artery by subtracting the DC component of the second pressure signal output from the pressure sensor spaced apart from the carotid artery from one pressure signal Signal Carotid pressure wave detecting apparatus characterized by the means comprises.