JPH0810301Y2 - Pulse wave detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to an improvement of a pulse wave detecting device.

2. Description of the Related Art A convex portion is formed on a pressing surface that is pressed by a living body, and a pressure detecting element is provided on the tip surface of the convex portion, and the convex portion is generated from the artery by pressing it onto the artery on the living body surface. A pulse wave detection device that detects a pressure pulse wave is known. For example, the pulse wave detecting device described in Japanese Patent Application Laid-Open No. 1-126205 is that. Since tendons and bones are often located in the vicinity of the arteries of the living body where pulse waves are detected, the convex portion protruding from the pressing surface as described above does not interfere much with the tendons and bones and arteries. There is a feature that can be pressed appropriately.

The problem to be solved by the invention is that when detecting a pulse wave, a pressure is applied so that a flat part is formed on a part of the arterial wall in order to detect a pressure that is as close as possible to the pressure in the artery. It may be required to maintain the optimum pressing condition for For this reason,
If the protruding amount of the convex portion is set so that it can be appropriately pressed against the artery at a shallow position from the body surface, it may be excessive for the artery at a deep position from the body surface due to interference between the pressing surface and the tendon or bone. Not only will it be necessary to press with the pressing force, which will cause pain, but in some cases the optimum pressing conditions may not be realized. On the contrary, if the protruding amount of the convex part is set so that it can be appropriately pressed against the artery at the deep position from the body surface, the convex part is pressed with an extremely weak pressing force against the artery at the shallow position from the body surface. Instead, the pressing surface around the convex portion floats from the body surface and becomes unstable, and the optimum pressing condition cannot be maintained, so that the pulse wave signal cannot be stably detected.
That is, since there is a large individual difference in the depth position from the skin surface of the artery under the skin of the living body, for example, the radial artery or the dorsalis pedis artery, the optimum pressing condition should be set by using the convex portion with a certain protruding dimension. It could not be realized.

The present invention has been made in view of the above circumstances, and its purpose is to stably detect a pressure pulse wave regardless of the position of the artery from the body surface and to give pain. It is to provide a pulse wave detecting device that does not have the above.

Means for Solving the Problems The gist of the present invention for achieving the above-mentioned object is that a convex portion is formed on a pressing surface to be pressed by a living body, and a pressure detecting element is provided on a tip surface of the convex portion. In the pulse wave detecting device of another type, a soft elastic member having a height substantially equal to or higher than that of the convex portion and capable of being compressed and deformed is provided around the convex portion.

According to the pulse wave detecting device configured as described above, according to the pulse wave detecting device, the soft elastic member that has a height substantially equal to or higher than that of the convex portion and is compressively deformable is provided around the convex portion. Therefore, in the pressed state in which the artery is pressed by the convex portion in order to detect the pressure pulse wave, the soft elastic member is pressed and compressed and deformed by the bone or tendon located near the artery, and from the surface of the soft elastic member. The protrusion is appropriately projected. That is, by setting the protrusion amount from the pressing surface of the convex portion to be larger than that of the conventional art, there is no interference between the pressing surface and the tendon or the bone with respect to the artery deep in the body surface, and the elasticity of the soft elastic member Optimal pressing conditions can be obtained without excessively increasing the pressing force due to deformation. Further, for the artery at a position shallow from the body surface, the soft elastic member comes into contact with the tendon and the bone to stabilize the pressing state, and it is possible to preferably prevent the pressing posture from tilting and stabilize the pressure pulse wave. Can be detected. Therefore, according to the pulse wave detecting device of the present invention, the pressure pulse wave can be stably detected regardless of the position of the artery from the body surface, and no pain is caused.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

In FIG. 1, reference numeral 10 denotes a housing having a bottomed rectangular tube shape, which is detachably attached to a wrist by a band 14 with its open end facing the body surface 12 of a human body. Inside the housing 10 is a diaphragm 18
A pulse wave sensor 20 is provided so as to be capable of projecting from the open end of the housing 10 via the, and the housing 10 and the diaphragm 18 form a pressure chamber 22. A pressure fluid such as pressure air is supplied from the air pump 24 to the pressure chamber 22 via the pressure regulating valve 26, whereby the pulse wave sensor 20 responds to the pressure in the pressure chamber 22. The body surface 12 is pressed by the pressing force.

The pulse wave sensor 20 includes the pressing surface 28 on the side opposite to the diaphragm 18 side to the opening side of the housing 10, that is, the body surface 12
It is provided with a convex portion 30 protruding to the side, and a plurality of semiconductor pressure-sensitive elements 34 are provided on the tip surface 32 of the protruding end of the convex portion 30, for example 0.3 m
The radial arteries 35 are arranged at intervals of m.
The pulse wave sensor 20 detects the pressure vibration wave, that is, the pressure pulse wave generated from the radial artery 35 and transmitted to the body surface 12 by being pressed on the radial artery 35 of the body surface 12 by the distal end surface 32 thereof. . The electric signal output from the pulse wave sensor 20, that is, the pulse wave signal SM representing the pressure pulse wave is supplied to the control device 36.

The control device 36 is configured by including a microcomputer, processes an input signal according to a program stored in advance, outputs a drive signal SD ₁ to the pressure regulating valve 26, and outputs the pressure chamber 22.
The pressure inside the pressure chamber 22 is adjusted, and the optimum pressing force of the pulse wave sensor 20 is determined based on the pulse wave signal SN that is sequentially sampled in the process of gradually increasing the pressure in the pressure chamber 22. The pressure pulse wave is detected based on the pulse wave signal SM and the display / recording signal SI is output to display / record the detected pressure pulse wave on the display / recording device 38.

The height of the convex portion 30 projecting from the pressing surface 28 of the pulse wave sensor 20 is the same as the conventional height (about 1 mm) so as to cope with individual differences in depth from the body surface 12 to the radial artery 35. The pulse wave sensor is set to about 3 times the
On the pressing surface 28 of 20, a longitudinal pad 40, which is located on the outer peripheral side of the convex portion 30 and whose longitudinal direction is parallel to the radial artery 35, is fixed by means of bonding or the like. As shown in detail in FIG. 2, the convex portion 30 has a rectangular shape as a whole,
The pad 40 is arranged adjacent to two sides, which are parallel to the radial artery 35, of the four sides forming the rectangular shape. The reason why the pad 40 is not provided in the vicinity of two sides of the four sides of the convex portion 30 that are perpendicular to the radial artery 35 is to prevent unnecessary compression of the radial artery 35. The material, hardness, contact area, and thickness of the pad 40 described above are such that when the radial artery 35 is shallow from the body surface 12, the pad 40 abuts the tendon 42 and the radius 44 from the body surface 12 and the pulse wave sensor 20. The optimal pressing state can be maintained in a stable posture, and the radial artery 35 is
When the depth is deep, the pad 40 which is in contact with the tendon 42 and the radius 44 from the body surface 12 is easily compressed and deformed, and the convex portion 30 is shown in FIG. 1 without increasing the pressure in the pressure chamber 22 so much. Thus, it is determined that a part of the radial artery 35 can be appropriately crushed until it becomes flat. Specifically, the pad 40 is
For example, it is made of sponge-like urethane rubber, and its overall elastic constant is determined to be sufficiently smaller than that of the tendon 42 and sufficiently larger than that of the wall of the radial artery 35. The thickness of the pad 40 is
It is determined to be approximately the same as the height of 30. pad
This is because if 40 is lower than the height of the convex portion 30, there is a gap between the pad 40 and the body surface 12 when the radial artery 35 is shallow from the body surface 12, and the purpose cannot be achieved.

Next, the operation and effect of the pulse wave detecting device configured as described above will be described.

When it is determined that a start switch (not shown) has been operated to the ON state, the pressure inside the pressure chamber 22 is gradually increased to a predetermined constant pressure (for example, 250 mmHg), and each semiconductor is gradually increased during the gradual pressure increase process. The pressure pulse wave is sequentially detected by the pressure sensitive element 34, and the pulse wave signal SM representing each pressure pulse wave is stored together with the pressure in the pressure chamber 22, and then the pressure chamber 22 is exhausted. Then, the pressure of the pressure chamber 22 when it is determined that a part of the wall of the radial artery 35 has become flat based on the pulse wave signal SM output from each semiconductor pressure sensitive element 34 of the pulse wave sensor 20. The pressure is determined as the pressure corresponding to the optimum pressing force, and thereafter the pressure regulating valve 26 is driven so as to maintain that pressure. Further, among the semiconductor pressure-sensitive elements 34, the element that outputs the signal with the maximum amplitude is determined as the active element located right above the center of the radial artery 35.

As described above, the pressure pulse wave detected by the semiconductor pressure-sensitive element 34 located right above the center of the radial artery 35 is considered to be hardly affected by the elastic force (tension) of the wall of the radial artery 35. Accordingly, the pressure in the radial artery 35, that is, its waveform as a blood pressure fluctuation wave, is displayed, and the upper peak value and the lower peak value thereof are displayed as the maximum blood pressure value and the minimum blood pressure value on the display / recording device 38.

In the above pulse wave detecting device, as described above, since the pad 40 having a height substantially equal to or higher than that of the convex portion 30 and capable of being compressed and deformed is provided around the convex portion 30, the pressure pulse wave is obtained. In the pressed state in which the radial artery 35 is pressed by the convex portion 30 to detect, the pad 40 is pressed and deformed by the radius 44 and the tendon 42 located near the radial artery 35, and the surface of the pad 40 is compressed. The protrusion 30 is appropriately projected from the. That is, by setting the protruding amount of the convex portion 30 from the pressing surface 28 to be larger than that of the conventional one, for the radial artery 35 at a position deeper than the body surface 12, the pressing surface 28 and the tendon 42 or the radius 44 interfere with each other. Therefore, the optimum pressing condition can be obtained without excessively increasing the pressing force of the pulse wave sensor 20 due to the elastic deformation of the pad 40. For the artery at a position shallower than the body surface 12, the pad 40 abuts on the tendon 42 and the radius 44 to stabilize the pressed state, and the pulse wave sensor 20
It is possible to preferably prevent the pressing posture of the vehicle from tilting, and to stably detect the pressure pulse wave. Therefore, according to the pulse wave detecting apparatus of the present embodiment, the pressure pulse wave can be stably detected regardless of the position of the artery from the body surface and no pain is caused.

Further, according to this embodiment, the pad 40 is disposed adjacent to two sides of the four sides forming the rectangular shape of the convex portion 30 which are parallel to the radial artery 35, and the four sides of the convex portion 30 are arranged. Radial artery of
Since the pad 40 is not provided in the vicinity of the two sides perpendicular to the 35, the radial artery 35 is not unnecessarily pressed by the pad 40,
The pressure pulse wave is detected more accurately.

Although one embodiment of the present invention has been described above, the present invention can be implemented in other modes.

For example, in the above-described embodiment, the pad 40 is provided on the pressing surface 28 of the pulse wave sensor 20 on the outer periphery of the convex portion 30 and at a position that does not press the radial artery 35, but it is provided on the entire circumference of the convex portion 30. It may be provided.

Further, the pad 40 may have a thickness larger than the height of the convex portion 30 in its natural state.

Further, in the above-mentioned embodiment, the pad 40 as the soft elastic member is made of a sponge made of urethane rubber, but it is not always necessary. For example, if the hardness is sufficiently low, a rubber block that is not a sponge is used. The soft elastic member may be configured, or the soft elastic member may be configured in a rubber bag in which a liquid or gas is sealed. As the rubber bag, for example, a rubber tube in which both ends are closed is used. When a rubber bladder filled with a fluid is used as the soft elastic member, the rubber bladder is freely deformed according to the uneven shape of the living body surface when the pulse wave sensor is pressed, so that the pressing force by the soft elastic member is The pressure is made uniform over the entire pressing surface, and it is possible to more effectively prevent the subject from suffering. When a rubber bladder filled with a fluid is used as the soft elastic member, if the fluid pressure in the rubber bladder is adjustable, the tip surface of the convex portion of the pulse wave sensor and the pressing surface of the rubber bladder are pressed. The initial relative position in the direction can be adjusted according to the subject, or the fluid in the rubber sac that solidifies when leaking from the rubber sac to the outside, such as a rubber adhesive, Even if the fluid in the bladder leaks, there is an advantage that the leak can be self-repaired.

Further, in the above-described embodiment, the pulse wave sensor 20 is configured to be pressed by the air pressure, but it may be configured to be pressed by the feed screw mechanism driven by the electric motor.

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

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a pulse wave detecting device to which the present invention is applied, and is a diagram showing an example of a state in which a pulse wave sensor is pressing with an optimum pressing force. FIG. 2 is a front view of the pulse wave sensor of the apparatus shown in FIG. 12: Body surface 20: Pulse wave sensor 28: Pressing surface 30: Convex part 35: Radial artery 40: Pad (soft elastic member)

Claims (1)

[Scope of utility model registration request] 1. A pulse wave detecting device of a type in which a convex portion is formed on a pressing surface to be pressed against a living body, and a pressure detecting element is provided on a tip end surface of the convex portion. A pulse wave detecting device, characterized in that a soft elastic member having a thickness and capable of being compressed and deformed is provided around the convex portion.