JP7053990B2 - Sensor module fixing device - Google Patents

Description

The present disclosure relates to a sensor module fixing device, and particularly to a fixing device for fixing a sensor module for blood pressure measurement to the body surface of a subject.

To measure blood pressure in general, first, a compression part called a cuff is inflated to completely crush the artery in the arm, and the arterial blood flow is temporarily stopped. Then, the pressure of the cuff is gradually reduced, and the pressure at which the arterial blood flow resumes is measured. Resumption of arterial blood flow is detected by noise (Korotkoff sounds) derived from arterial blood flow or skin vibration on the arteries.

In risk management during hemodialysis, it may be required to continuously measure blood pressure during dialysis therapy. However, the method of stopping blood flow with a cuff is not suitable for long-term continuous measurement because the arm is fixed and strongly pressed. Although there are small devices that can be attached to fingertips to measure blood pressure, such devices have low measurement accuracy and are problematic for use in risk management of hemodialysis.

As a method of measuring blood pressure without stopping blood flow, a method of measuring pressure fluctuation of a blood vessel wall has been studied (see, for example, Patent Document 1). In this case, a pressure sensor is installed on the skin on the artery of the arm, and a pressure that does not crush the artery is applied by inflating a flexible bag or the like. As a result, fluctuations in arterial pressure (blood pressure) are transmitted to the sensor, so blood pressure can be continuously measured.

International Publication No. 2004/069049

However, inflating the flexible bag and applying the appropriate pressure requires fine adjustment, and it is necessary to measure whether or not the appropriate pressure is applied each time by using some pressure measuring means. .. In addition, a compressor or the like for inflating the bag is required, which makes the device large-scale.

An object of the present disclosure is to make it possible to easily attach a sensor for measuring blood pressure to a measurement site.

One aspect of the sensor module fixing device of the present disclosure is a hinge portion that rotatably connects the first arm and the second arm that sandwich the measurement site including the target blood vessel, and the first arm and the second arm at the fixed end. The first arm has an opening to which a sensor module for measuring blood pressure based on the up-and-down movement of the target blood vessel is attached, and the hinge portion is a free end of the first arm and a second arm. It has a one-way clutch that rotates only in the direction in which the distance from the free end becomes smaller, and the sensor module attached to the opening is in a state of being relatively stationary with respect to the measurement site sandwiched between the first arm and the second arm. The measurement surface comes into contact with the skin surface directly above the target blood vessel.

With such a configuration, the sensor module can be fixed to the measurement site in a state of being relatively stationary with respect to the measurement site without applying a large pressure. Therefore, the magnitude of the vertical movement due to the pulsation of the target blood vessel can be accurately transmitted to the sensor module, and high-precision blood pressure measurement can be continuously performed.

In one aspect of the sensor module fixing device, the sensor module is attached to the opening via the sensor mounting portion, and the opening extends in the direction in which the long axis connects the free end and the fixed end of the first arm to mount the sensor. The portion can be slidably attached to the opening in the longitudinal direction. With such a configuration, it becomes easy to deal with various subjects.

In one aspect of the sensor module fixing device, the width of the second arm can be wider than the width of the first arm. With such a configuration, the sensor module can be more stably fixed to the measurement site.

In one aspect of the sensor module fixing device, the sensor module has a strain sensor, a rigid transmission member, and a case for accommodating the strain sensor and the transmission member, and the upper end of the transmission member is in contact with the strain sensor and the lower end thereof. Is exposed from the bottom surface of the case and is held in the case so as to be movable in the vertical direction and restricted in the horizontal movement, and the lower end of the transmission member can be a measurement surface. With such a configuration, it is possible to accurately detect the vertical movement due to the pulsation of the target blood vessel and perform accurate blood pressure measurement.

One aspect of the blood pressure measuring device of the present disclosure comprises the sensor module fixing device of the present disclosure and a sensor module detachably attached to an opening. With such a blood pressure measuring device, continuous blood pressure measurement for a long period of time can be easily and accurately performed.

According to the sensor module fixing device of the present disclosure, a sensor module for measuring blood pressure can be easily attached to a measurement site.

It is a perspective view which shows the sensor module fixing instrument which concerns on one Embodiment. It is sectional drawing which shows the sensor module fixing instrument which concerns on one Embodiment. It is sectional drawing which shows an example of the sensor module attached to the sensor module fixing instrument. It is a perspective view which shows the modification of the sensor module fixing instrument.

As shown in FIGS. 1 and 2, the sensor module fixing device 100 of the present embodiment can fix the sensor module 200 for blood pressure measurement to the measurement site 300 such as the forearm of the subject, and the measurement site 300 can be fixed. It includes a first arm 101 and a second arm 102 to be sandwiched.

The first arm 101 and the second arm 102 are connected to each other at a fixed end by a hinge portion 103, and the first arm 101 and the second arm 102 can rotate each other with the hinge portion 103 as a rotation axis. can. The hinge portion 103 has a one-way clutch, and when it is in a restricted state, the hinge portion 103 rotates the free end, which is the end opposite to the fixed end of the first arm 101 and the second arm 102, only in a direction approaching each other. When it is in the open state, it can be rotated in both directions.

The first arm 101 has an opening 101a to which the sensor module 200 for blood pressure measurement is attached. The first arm 101 and the second arm 102 can sandwich the measurement site 300 so that the target blood vessel 301 of the measurement site 300 overlaps with the position of the opening 101a.

The sensor module 200 is detachably attached to the opening 101a via the sensor attachment portion 105. The opening 101a has a substantially rectangular shape in a plane extending in a direction in which the long axis connects the fixed end side and the free end side of the first arm, and the sensor mounting portion 105 is slidably attached to the opening 101a in the long axis direction. ing. Specifically, a slide convex portion 101b is provided on the side wall of the opening 101a, and a groove provided on the side surface of the sensor mounting portion 105 engages with the slide convex portion 101b. A slide groove may be provided on the side wall of the opening 101a, and a convex portion may be provided on the side surface of the sensor mounting portion 105.

The sensor mounting portion 105 has a mounting hole 105a penetrating vertically, and the sensor module 200 is removably inserted into the mounting hole 105a. A flexible piece 200a having a protrusion is provided on the side surface of the sensor module 200, and can be removably inserted into the mounting hole 105a without applying a large force.

The shape of the measurement site 300 and the position of the target blood vessel 301 at the measurement site 300 differ depending on the subject. By movably mounting the sensor module 200 to the opening 101a via the sensor mounting portion 105, it is possible to handle various subjects. However, the sensor module 200 may be directly attached to the opening 101a. Further, the sensor module 200 can be fixed to the opening 101a so as not to move.

The sensor module 200 attached to the opening 101a can measure blood pressure based on the vertical movement of the target blood vessel 301 due to the pulsation. As an example of a specific configuration, as shown in FIG. 3, it has a strain sensor 201, a transmission member 203, and a case 205 accommodating the strain sensor 201 and the transmission member 203. The transmission member 203 is a rigid body that transmits the vertical movement of the target blood vessel 301 existing at the measurement site 300 to the strain sensor 201. The upper end of the transmission member 203 is in contact with the strain sensor 201, and the lower end is exposed from the bottom surface of the case 205 to be a measurement surface that abuts on the measurement site 300.

If the measurement surface is in contact with the skin covering directly above the target blood vessel 301 in a state where the case 205 is relatively stationary with respect to the measurement site 300, the transmission member 203 also responds to the vertical movement of the target blood vessel 301 due to the pulse. It moves up and down and the force is transmitted to the strain sensor 201. As a result, the distortion sensor 201 is distorted, and a signal corresponding to the magnitude of the distortion is output. By measuring in advance the correlation between the pressure required to lift the transmission member 203 and the output of the strain sensor 201, the blood pressure can be obtained from the signal value of the strain sensor 201.

When measuring blood pressure with such a sensor module 200, it is important that the position of the case 205 is fixed with a constant force that does not move due to pulsation and does not hinder the vertical movement of the transmission member 203. When the case 205 is fixed by a belt or the like wrapped around the measurement site 300, if the tightening force is too weak, not only the transmission member 203 but also the case 205 will move up and down due to the pulsation of the target blood vessel 301. On the other hand, if the tightening force is too strong, pressure is applied to the blood vessels and accurate blood pressure cannot be measured. When the sensor module is fixed to the measurement site 300 by a flexible member such as a belt, both the belt and the measurement site 300 are deformed, so that it is difficult to accurately adjust the tightening force.

In the sensor module fixing device 100 of the present embodiment, the rigid first arm 101 and the second arm 102 are connected via a hinge portion 103 having a one-way clutch. With the hinge portion 103 in the restricted state, the first arm 101 and the second arm 102 are brought into contact with the surfaces of the measurement site 300 on opposite sides of each other. Since the rigid first arm 101 and the second arm 102 are hardly deformed, the case 205 is hardly moved up and down due to the pulsation of the blood vessel only by lightly sandwiching the measurement site 300. Therefore, accurate blood pressure measurement can be easily performed.

The first arm 101 and the second arm 102 can be formed of a member that is hard to some extent, for example, polyethylene, polypropylene, acrylonitrile-butadiene-styrene copolymer (ABS), polycarbonate, hard vinyl chloride, polyamide, polyimide and It can be formed of a resin such as polyether sulfone.

In the sensor module fixing device 100 of the present embodiment, the distance between the first arm 101 and the second arm 102 while visually recognizing the position of the target blood vessel 301 of the measurement site 300 from the attachment hole of the opening 101a or the sensor attachment portion 105. Can be made smaller. Therefore, it becomes easy to accurately arrange the sensor module 200 on the target blood vessel 301. The position of the target blood vessel 301 is easily visible from the skin surface in the case of a shunt blood vessel. When it is difficult to see from the skin surface like a normal artery, the position can be visually recognized by attaching a marker indicating the position of the target blood vessel 301 to the skin surface in advance.

The first arm 101 and the second arm 102 are preferably curved to match the shape of the measurement site 300. For example, when the measurement site 300 is a forearm, it is preferable that the cross section of the space formed between the first arm 101 and the second arm 102 has a substantially elliptical shape. For example, if an elliptical space having a major axis of about 60 mm and a minor axis of about 45 mm is created, it is possible to accommodate the forearms of many general subjects. The size can be appropriately changed according to the subject and the measurement site.

The widths of the first arm 101 and the second arm 102 are not particularly limited as long as the sensor module 200 can be attached, and from the viewpoint of miniaturizing the instrument, the widths of the first arm 101 and the second arm 102 are used. It is preferable to make them almost the same. However, as shown in FIG. 4, the width of the second arm 102 may be larger than the width of the first arm 101. With such a configuration, the contact surface between the measurement site 300 and the second arm 102 can be made large, so that the position of the sensor module fixing device 100 can be further stabilized. The width of the first arm 101 and the second arm 102 is the length in the direction of intersecting the fixed end and the free end.

The one-way clutch provided on the hinge portion 103 may have, for example, an inner ring and an outer ring, and may be configured such that the outer ring can rotate in one direction with respect to the inner ring and is locked and does not rotate in the other direction. In this case, the second arm 102 is fixed to the inner ring, and the first arm 101 is engaged with the outer ring in the restricted state. As a result, the first arm 101 moves only in the direction approaching the second arm 102 by the one-way clutch. On the other hand, in the released state, the first arm 101 and the outer ring are made independent. As a result, the first arm 101 can also move in a direction away from the second arm.

In addition, for example, the first arm 101 is fixed to the outer ring, the second arm 102 is fixed to the inner ring, and the inner ring and the outer ring engage with each other and rotate only in one direction in the restricted state, and the inner ring rotates in only one direction in the released state. It is also possible to disengage the engagement with the outer ring and rotate in both directions.

The strain sensor 201 used in the sensor module 200 is not particularly limited, but a strain gauge 211 having a strain gauge 211 attached to the surface of the leaf spring 212 as shown in FIG. 3 can be used. In this case, the magnitude of the strain generated in the leaf spring 212 can be measured by the strain gauge 211 attached to the leaf spring 212.

The strain gauge 211 is preferably one with as high sensitivity as possible and low power consumption. For example, a strain gauge having a gauge ratio of 2 or more, preferably 5 or more, more preferably 10 or more, still more preferably 20 or more can be used. For example, a metal resistance strain gauge, a semiconductor strain gauge, a magnetostrictive effect type strain gauge, or the like can be used. Above all, a semiconductor strain gauge using a semiconductor piezo resistance element is preferable because of its high sensitivity and low power consumption.

In addition, the present invention is not limited to such a configuration, and a sensor having a configuration in which a diaphragm or the like and a strain gauge are combined, an optical fiber type sensor, or the like can also be used.

The transmission member 203 may have any configuration as long as it can transmit the vertical movement of the target blood vessel 301 to the strain sensor 201, and may be, for example, a columnar or a prismatic shape. The material of the transmission member 203 is not particularly limited, and may have enough rigidity to transmit the vertical movement of the target blood vessel 301 to the strain sensor 201. The transmission member 203 should be as light as possible so as not to interfere with the vertical movement of the target blood vessel 301. The transmission member 203 can be, for example, a molded body made of a hard resin. In order to make it lighter, the inside of the transmission member 203 can be made hollow.

In the present embodiment, the bottom surface of the transmission member 203, which is the measurement surface, is a hemispherical surface. With such a configuration, blood pressure measurement for arteries becomes easy.

When the strain sensor 201 is a sensor using the leaf spring 212, it is preferable to reduce the contact area between the transmission member 203 and the leaf spring 212 in order to accurately transmit the vertical movement of the target blood vessel 301 to the leaf spring 212. For example, a protrusion can be provided at the upper end of the transmission member 203. The protrusions can be provided in a dot shape at the center or in a ridge shape that crosses in the radial direction. However, the configuration of the contact portion between the transmission member 203 and the strain sensor 201 may be determined according to the configuration of the strain sensor 201.

The sensor module 200 may have a drive unit 231 for driving the strain sensor 201. The drive unit 231 may select an appropriate circuit according to the type of the strain sensor 201 to be used. In the case of a strain sensor that causes a change in resistance, for example, a Wheatstone bridge circuit can be used.

The drive unit 231 may include a signal processing unit that converts a signal received from the strain sensor 201 into a blood pressure value. The obtained blood pressure value can be output from the output terminal to an external processing device. However, it is also possible to output the signal of the strain sensor 201 without converting it into blood pressure, and perform signal processing in an external processing device. The drive unit 231 and the external processing device can be connected by wire or wirelessly. The drive unit 231 can also be provided outside the sensor module 200.

By using the sensor module fixing device 100 of the present embodiment, the sensor module 200 for blood pressure measurement can be easily mounted on the target blood vessel 301 to continuously measure the blood pressure.

For example, first, the second arm 102 is arranged on a table or the like, and the measurement site 300 is arranged on the second arm 102. After that, with the hinge portion 103 in the restricted state, the first arm 101 is brought closer to the second arm 102 until the first arm 101 comes into contact with the measurement site 300. At this time, the first arm 101 can be moved while visually recognizing the target blood vessel 301 itself or a marker or the like indicating the position thereof from the opening 101a. As a result, the measurement site 300 can be easily sandwiched by the sensor module fixing device 100 so that the opening 101a overlaps with the target blood vessel 301. Subsequently, the mounting portion 105 is slid so that the target blood vessel 301 is located at the center of the mounting hole 105a. After that, the sensor module 200 is attached to the attachment hole 105a. In this way, the measurement surface of the sensor module 200 can be easily brought into contact with the skin surface directly above the target blood vessel 301.

Since the first arm 101 does not move in the direction away from the second arm 102 by the one-way clutch, the position of the sensor module 200 can be fixed in a state of being relatively stationary with respect to the measurement site without applying a large pressure. Therefore, the magnitude of the vertical movement due to the pulsation of the target blood vessel 301 can be accurately transmitted to the strain sensor 201 via the transmission member 203, and accurate blood pressure measurement becomes possible. Further, since the measurement site 300 is not pressed with a large force, the burden on the subject is small and it becomes easy to continuously measure the blood pressure.

After the measurement is completed, the sensor module fixing device 100 can be easily removed by opening the hinge portion 103 and expanding the sense between the first arm 101 and the second arm 102.

The sensor module fixing device 100 of the present embodiment can be used for blood pressure measurement using the artery of the forearm as the target blood vessel 301. Further, the target blood vessel 301 can be used as an anastomotic portion of a shunt blood vessel provided on the forearm. When measuring blood pressure by a shunt blood vessel, it is preferable that the bottom surface of the transmission member 203 is a flat surface and the surface of the raised skin on the shunt blood vessel is brought into surface contact with the measurement surface. This makes it possible to accurately transmit the vertical movement of the shunt blood vessel.

The blood pressure measurement site 300 to which the sensor module fixing device 100 of the present embodiment is attached is not limited to the forearm, but may be other parts of the body such as the upper arm, the thigh, and the lower leg.

The sensor module fixing device of the present disclosure can easily attach a sensor module for measuring blood pressure to a measurement site, and is particularly useful as a blood pressure measuring device or the like for continuous blood pressure measurement.

100 Sensor module fixing device 101 1st arm 101a Opening 101b Slide convex 102 2nd arm 103 Hing part 105 Sensor mounting part 105a Mounting hole 200 Sensor module 200a Flexible piece 201 Sensor 203 Transmission member 205 Case 211 Gauge 212 Leaf spring 231 Drive 300 Measurement site 301 Blood vessel

Claims (5)

It is provided with a first arm and a second arm that sandwich a measurement site including a target blood vessel, and a hinge portion that rotatably connects the first arm and the second arm at a fixed end.
The first arm has an opening to which a sensor module for measuring blood pressure based on the vertical movement of the target blood vessel due to pulsation is attached.
The hinge portion has a one-way clutch that rotates only in a direction in which the distance between the free end of the first arm and the free end of the second arm becomes small.
In the sensor module attached to the opening in a state where the first arm and the second arm are brought close to each other and the measurement portion is sandwiched, the case is sandwiched between the first arm and the second arm. A sensor module fixing device that is in a state of being relatively stationary with respect to a site, the measurement surface is in contact with the skin surface directly above the target blood vessel, and is moved up and down by the pulsation of the target blood vessel . The sensor module is attached to the opening via the sensor attachment.
The opening extends in a direction in which the long axis connects the free end and the fixed end of the first arm.
The sensor module fixing device according to claim 1, wherein the sensor mounting portion has a sensor module mounting hole to which the sensor module can be detachably mounted and is slidably mounted in the opening in the long axis direction. The sensor module fixing device according to claim 1 or 2, wherein the width of the second arm is wider than the width of the first arm. The sensor module has a strain sensor expropriated in the case and a transmission member that is a rigid body.
The transmission member is held in the case so that the upper end is in contact with the strain sensor, the lower end is exposed from the bottom surface of the case, and the transmission member is movable in the vertical direction and restricted in horizontal movement.
The sensor module fixing device according to any one of claims 1 to 3, wherein the lower end of the transmission member serves as the measurement surface. The sensor module fixing device according to any one of claims 1 to 4.
A blood pressure measuring device including a sensor module detachably attached to the opening.

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