JP2000193546A - Catheter with pressure detection mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catheter with a pressure detection mechanism in a structure that has a high pressure detection accuracy and is suited for miniaturization. SOLUTION: A reference pressure chamber 27 is divided on the upper surface side of a chip support 11 in a lumen 3. An atmospheric pressure introduction tube 28 for communicating the reference pressure chamber 27 with an atmospheric pressure region outside a catheter tube 2 is provided in the catheter tube 2. A reference pressure introduction path 25 for connecting the reference pressure chamber 27 and a back pressure chamber 31 is formed in the chip support 11, thus introducing a reference pressure into the back pressure chamber 31 that is divided by the reverse side of a pressure sensor chip 17 and the front surface of the chip support 11 via the atmospheric pressure introduction pipe 28, the reference pressure chamber 27, and the reference pressure introduction path 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catheter with a pressure detecting mechanism.

[0002]

2. Description of the Related Art Conventionally, a catheter with a pressure detecting mechanism using a pressure sensor chip in a sensor section has been known. There are a relative pressure type and an absolute pressure type as a method of the sensor unit. Here, FIG. 7 shows a conventional example of a catheter with a pressure detection mechanism employing a relative pressure sensor unit.

The catheter tube 42 of the catheter 41 has one lumen 43 inside. The opening at the distal end of the tube 42 is sealed by a sealing plug (not shown), and the opening at the proximal end of the tube 42 communicates with the atmospheric pressure region. A relative pressure sensor 44 is formed in the lumen 43 at a position closer to the base end than the sealing plug. A pressure sensor chip 46 is mounted on the upper surface side of a pedestal 45 constituting the sensor section 44. A strain gauge 47 formed on the upper surface of the pressure sensor chip 46 is connected to a lead wire of a cable 49 via a bonding wire 48. A diaphragm 50 is formed on the pressure sensor chip 46. The surface of the diaphragm 50, which is a pressure-sensitive surface, is arranged so as to face an external pressure introduction port 51 provided on the peripheral surface of the tube 42. The inlet 51 is sealed with a soft material such as a silicone resin.
A concave portion 52 exists on the back surface side of the diaphragm portion 50, and a back pressure chamber 53 is defined between the back surface of the pressure sensor chip 46 and the upper surface of the pedestal 45.

The pedestal 45 is provided with a reference pressure introducing hole 54 penetrating the upper and lower surfaces. Therefore, in the back pressure chamber 53, the air pressure in the space on the lower surface side of the pedestal 45 (that is, the air pressure in the lumen 43) acts as the reference pressure via the reference pressure introduction hole 54.

[0005]

By the way, lumen 4
If an attempt is made to adopt a catheter structure having a balloon for vasodilation in 3, it becomes necessary to introduce and use a balloon inflation gas into the lumen 43. However, in this case, since the air pressure in the lumen 43 fluctuates, it becomes impossible to refer to the air pressure in that portion as the reference pressure. If this air pressure is referred to, the accuracy of the pressure detection by the sensor unit 44 necessarily decreases.

In the conventional catheter 41, a space of a certain size needs to be secured on the lower surface side of the pedestal 45 in order to introduce a reference pressure into the back pressure chamber 53. Therefore, this is one of the factors that hinder the miniaturization of the entire sensor unit 44. Therefore, the structure is not suitable for the multi-lumen type in which the sectional area of the lumen 43 must be reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a catheter with a pressure detection mechanism having high pressure detection accuracy and a structure suitable for miniaturization.

[0008]

According to the first aspect of the present invention, a pressure sensor chip is mounted on an upper surface of a tip support housed in a lumen of a catheter tube. In a catheter in which a reference pressure is introduced into a back pressure chamber defined by a back surface of the pressure sensor chip and an upper surface of the chip support, a reference pressure chamber is defined on the upper surface side of the chip support in the lumen. An atmospheric pressure introducing pipe communicating the reference pressure chamber and an atmospheric pressure region outside the catheter tube is provided in the catheter tube, and a reference pressure introducing path communicating the reference pressure chamber and the back pressure chamber is provided. The gist is a catheter with a pressure detection mechanism, which is formed in the tip support.

[0009] In the invention described in claim 2, in claim 1, the chip support has a two-layer structure, and the reference pressure introduction path is formed at an interface formed by the two layers.
According to a third aspect of the present invention, in the second aspect, the chip support is formed by attaching a printed wiring board to an upper surface of a pedestal, and the reference pressure introduction path is formed on an upper surface of the pedestal. It was determined to be a reference pressure introduction groove.

Hereinafter, the "action" of the present invention will be described. According to the invention described in claims 1 to 3, as a result of communication between the back pressure chamber and the atmospheric pressure region outside the catheter tube via the atmospheric pressure introducing pipe, the reference pressure chamber, and the reference pressure introducing path, the back pressure chamber Atmospheric pressure can be reliably introduced. Therefore, it is possible to refer to a suitable reference pressure having a small variation as compared with the case where the pressure in the lumen is introduced, thereby increasing the pressure detection accuracy by the sensor unit. Further, by disposing the reference pressure chamber and the back pressure chamber on the upper surface side of the chip support and communicating them via the reference pressure introduction path, it is not necessary to provide a space particularly on the lower surface side of the chip support. As a result, a sensor unit structure suitable for miniaturization can be obtained.

According to the second aspect of the present invention, since the chip support has an interface, the reference pressure introduction path can be formed relatively easily as compared with a chip support having no interface. Therefore, it is possible to provide a sensor unit structure which is simple to manufacture despite its small size.

According to the third aspect of the present invention, the reference pressure introducing groove can be formed relatively easily by forming a groove on the upper surface of the chip support without, for example, performing complicated hole processing on the chip support. Therefore, it is possible to provide a sensor unit structure which is simple to manufacture despite its small size.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] A catheter 1 with a blood pressure detecting mechanism according to one embodiment of the present invention will be described below in detail with reference to FIGS.

A catheter tube 2 constituting the catheter 1 is inserted into a blood vessel, and comprises a tube main body 2a and a tube main body 2a which constitute a major part thereof.
and a cover 2b attached to the front end of a. In the present embodiment, the catheter tube 2 has a diameter of about 2 m.
A polyurethane tube of about m is used. As shown in FIGS. 2A and 2B, three lumens 3, 4, and 5 are formed inside the catheter tube 2. That is, the catheter 1 of the present embodiment is a so-called multi-lumen type. The opening at the distal end of the tube 2 is sealed by a sealing plug 6 made of silicone rubber or the like.

A cover 2b, which is a part of the tube 2, is provided at a position near the base end of the sealing plug 6, and defines the first lumen 3 together with the tube main body 2a. The cover 2b of the present embodiment is a member having a substantially U-shaped cross section, and is made of a biocompatible material such as stainless steel. An external pressure inlet 8 for taking in the pressure on the outer peripheral surface of the tube 2 into the first lumen 3 is provided through a predetermined portion of the cover 2b. Immediately at the base end side of the external pressure introduction port 8, a wall portion 9 is provided so as to protrude inward. Then, the relative pressure sensor unit 7 of the present embodiment
Is mainly composed of an area partitioned by the cover 2b.

As shown in FIGS. 2A and 2B, the chip support 11 constituting the sensor section 7 is accommodated in the first lumen 3, and the back surface of the chip support 11 is It is adhered to the bottom of the first lumen 3.

As shown in FIGS. 1 to 3, the chip support 11 of the present embodiment is a plate-like member having a two-layer structure. The chip support 11 includes a pedestal 12 and a flexible substrate 13 as a printed wiring board. The pedestal 12 of the present embodiment is a substantially rectangular and elongated stainless steel member having dimensions of several mm in length, 1.2 mm in width,
The thickness is set to 0.4 mm. The flexible substrate 13 of the present embodiment is a thin printed wiring board having a thickness of about 0.05 mm having a conductor layer on one side. The flexible substrate 13 has a rectangular shape and is formed slightly shorter than the pedestal 12. In addition, the flexible substrate 13
Is set slightly smaller (specifically, about 1 mm) than the width of the pedestal 12. The conductor-free surface of the printed wiring board 13 is arranged downward and
Is adhered to the upper surface of the substrate with an adhesive.

The conductor formation surface of the flexible substrate 13 is arranged upward, and a plurality of conductor patterns 14 as a conductor layer, a first pad 15 and a second pad 16 are formed on the surface. 5 conductor patterns 1
Reference numerals 4 extend in the longitudinal direction of the flexible substrate 13 and in parallel at equal intervals. The first pad 15 is provided on the front end side of each conductor pattern 14, and the second pad 16 is provided on the base end side of each conductor pattern 14. The five first pads 15 are arranged on a straight line parallel to the width direction of the flexible substrate 13. Similarly, the five second pads 16 are arranged on a straight line parallel to the width direction of the flexible substrate 13.

A semiconductor pressure sensor chip 17 is mounted on the upper surface side of the flexible substrate 13 in a region on the tip side of the row formed by the first pads 15.
Here, the sensor chip 17 is bonded using an adhesive made of a heat-resistant resin such as a silicone resin. When the sensor unit 7 is accommodated, the sensor chip 17 is placed at a position closer to the distal end than the wall 9, in other words, at a position corresponding to the external pressure inlet 8. The sensor chip 17 is formed using a substantially rectangular silicon substrate as a base. As shown in FIG. 2A, an etching recess 18 is formed in the silicon substrate at a substantially central portion on the rear surface side. As a result, the etching recess 1
The portion corresponding to 8 is a thin diaphragm portion 19. A plurality of diffusion strain gauges 20 are formed on the surface of the diaphragm 19. In addition, the sensor chip 1
A plurality of bonding pads 21 are formed at the base end edge of the upper surface of 7. Each bonding pad 21 and each diffusion strain gauge 20 are connected via a wiring pattern (not shown) formed on the sensor chip 17. Also,
Each bonding pad 21 and each first pad 15 are bonded to each other via bonding wires 22.

As shown in FIG. 2A, the portion where the external pressure inlet 8 is located is sealed by a sealing material 23 made of a biocompatible material such as silicone gel. Therefore, the sensor chip 17, the pads 15, 21, the bonding wires 22, and the like are protected without being exposed to the outside.

Each lead wire exposed from the starting end of the flat cable 24 is soldered to each second pad 16 on the flexible substrate 13. The flat cable 24 is disposed in the first lumen 3, and the terminal thereof is drawn out from the base end of the tube 2.

Next, a reference pressure introducing structure in the sensor section 7 of the catheter 1 of the present embodiment will be described. FIG.
As shown in (a), a space defined by the back surface of the pressure sensor chip 17 and the upper surface of the printed wiring board 13 constituting the chip support 11 is provided with a back pressure chamber 31 into which a reference pressure is to be introduced. Has become. That is, the back pressure chamber 31 of the sensor section 7 is disposed on the upper surface side of the chip support 11 in the first lumen 3.

On the other hand, a reference pressure chamber 27 is defined in a predetermined area in the first lumen 3. The reference pressure chamber 27 of the present embodiment is formed on the upper surface side of the chip support 11 between the base side surface of the wall 9 and the front side surface of the sealing material 30. Therefore, the reference pressure chamber 27 is isolated from the chip accommodation space on the distal end side of the wall 9 and the space on the proximal end side of the sealing material 30. Therefore, even if the air pressure in the space closer to the base end than the sealing material 30 fluctuates, the influence does not spread to the reference pressure chamber 27.

As shown in FIGS. 2A and 2B, a flexible introduction pipe 28 as an atmospheric pressure introduction pipe is provided in the first lumen 3 of the catheter tube 2. I have. The distal end of the introduction pipe 28 is fitted into a fixed concave portion 29 having a substantially semicircular cross section formed on the inner wall surface of the cover 2b, and the base end thereof is immediately sealed by the sealing material 30. Therefore, the opening on the distal end side of the introduction pipe 28 is located in the reference pressure chamber 27. It can be understood that the tip of the introduction pipe 28 is arranged on the upper surface side of the chip support 11. The proximal end of the introduction pipe 28 is drawn out of the proximal end of the tube 2 to the outside thereof. Therefore, the base end opening of the introduction pipe 28 is located in the atmospheric pressure region. That is, the introduction pipe 28 plays a role of introducing atmospheric pressure into the reference pressure chamber 27 by communicating the reference pressure chamber 27 with an atmospheric pressure region outside the catheter tube 2.

The sensor section 7 has a reference pressure introducing passage for communicating the reference pressure chamber 27 with the back pressure chamber 31.
The reference pressure introduction path of the present embodiment is formed at the interface between both layers in the chip support 11 having a two-layer structure, that is, at the interface formed by the upper surface of the pedestal 12 and the lower surface of the printed wiring board 13.
More specifically, a reference pressure introduction groove 25 is formed on the upper surface of the base 12 as a reference pressure introduction path.

As shown in FIG. 1 and the like, the reference pressure introducing groove 25 of the present embodiment has a substantially T-shape. The reference pressure introducing groove 25 includes a first region 25a and a second region 25b. No.
The one region 25a is formed at the center of the pedestal 12 so as to extend in parallel along the length direction thereof. The second region 25b is connected to the base end of the first region 25a and is formed so as to extend in parallel along the width direction of the pedestal 12. The cross section of the introduction groove 25 is rectangular, and the depth thereof is equal to or less than half the thickness of the pedestal 12 (specifically, about 0.1 mm to 0.2 mm). Therefore, the bottom of the reference pressure introducing groove 25 does not reach the lower surface of the pedestal 12.
Such a reference pressure introducing groove 25 can be formed, for example, by providing a resist having an opening on the upper surface of the pedestal 12 and performing wet etching in that state. As a method of processing and forming the reference pressure introducing groove 25, a method of performing dry etching in a state where a resist is provided, or mechanically damaging the resist may be adopted.

The first region 2 on the flexible substrate 13
A through hole 26 having a circular cross section is provided at a position corresponding to the tip of 5a. The through holes 26 are formed by, for example, punching the flexible substrate 13 with a punching jig or the like. The through-hole 26 is located directly below the diaphragm 19 of the sensor chip 17.

When the pedestal 12, the flexible substrate 13 and the sensor chip 17 are assembled as shown in FIG. 3, the upper opening of the reference pressure introducing groove 25 is almost completely covered by the flexible substrate 13. in this case,
The first region 25a side and the back pressure chamber 31 side communicate with each other through the through hole 26. Since the width of the flexible substrate 13 is slightly smaller than the width of the pedestal 12, the second region 25b
Are formed at positions corresponding to both ends of the space 25c. By these two gaps 25c, the second region 25b side and the reference pressure chamber 27 side communicate with each other. That is, the reference pressure introducing groove 25 plays a role of introducing atmospheric pressure into the back pressure chamber 31 by communicating the reference pressure chamber 27 with the back pressure chamber 31.

Next, the sensing operation by the catheter 1 will be described. When the catheter tube 2 is inserted into a blood vessel, the externally exposed surface of the sealing material 23 is constantly pressed by blood. The air taken in by the introduction pipe 28 is first introduced into the reference pressure chamber 27 via the introduction pipe 28, and is further introduced into the back pressure chamber 31 via the reference pressure introduction groove 25 and the through hole 26. I have. Therefore, the atmospheric pressure as the reference pressure always acts on the back surface side of the diaphragm portion 19.

If, for example, the blood pressure rises in this state, the force for pressing the externally exposed surface also increases, and the influence spreads to the surface side of the diaphragm 19 via the sealing material 23. That is, the blood pressure fluctuation occurring outside the sensor unit 7 is
The light is indirectly transmitted to the sensor chip 17 via the sealing material 23. Then, the strain of the diaphragm portion 19 increases, and the resistance value of the strain gauge 20 thereon changes.
That is, the blood pressure fluctuation is converted into an electric signal by the strain gauge 20. Such an electric signal is output to the outside of the tube 2 via the pad 21, the bonding wire 22, the pad 15, the conductor pattern 14, the pad 16, and the flat cable 24. Flat cable 24 is tube 2
Connected to the display device via an external connector (not shown), the electrical signals are processed there and visualized as required.

Therefore, according to the present embodiment, the following effects can be obtained. (1) Since the catheter 1 of the present embodiment is configured as having the above-described reference pressure introducing structure,
The back pressure chamber 31 communicates with the atmospheric pressure region outside the catheter tube 2. As a result, the atmospheric pressure can be reliably introduced into the back pressure chamber 31. Therefore, it is possible to refer to a suitable reference pressure having a small variation as compared with the case where the pressure in the first lumen 3 is directly introduced, and thereby the pressure detection accuracy by the sensor unit 7 is increased. Therefore, with this structure, even if, for example, a vascular inflation balloon is accommodated in the first lumen 3 and a balloon inflation gas is supplied thereto, the reference pressure does not change.

(2) In the catheter 1 of this embodiment, since the reference pressure chamber 27, the back pressure chamber 31, and the introduction pipe 28 are all arranged on the upper surface side of the chip support 11, There is no need to provide a space in particular on the lower surface side. Therefore, the thickness of at least the sensor unit 7 can be reduced by the amount that the space becomes unnecessary.
The use of the flexible substrate 13 as a printed wiring board also contributes to the overall thickness reduction of the chip support 11.

As described above, even if the sectional area of the first lumen 3 is small, the sensor section 7 can be surely formed therein. That is, it can be said that the sensor unit 7 of the present embodiment has a structure suitable for a multi-lumen type.

(3) Tip support 1 of this catheter 1
Reference numeral 1 denotes a two-layer structure, which includes a pedestal 12 and a flexible substrate 1
A reference pressure introducing groove 25 is formed at an interface between the reference pressure introducing groove 3 and the reference pressure introducing groove 3. Therefore, a desired reference pressure introducing groove 25 can be formed relatively easily by forming a groove on the upper surface of the pedestal 12 without performing complicated hole processing using a drill or the like. Therefore, the sensor unit 7 is simple to manufacture despite its small size. Further, the simplicity of manufacturing leads to a reduction in cost. Second Embodiment Next, a catheter 36 according to a second embodiment of the present invention will be described with reference to FIGS. Here, the differences from the first embodiment will be mainly described, and the common points will be denoted by the same reference numerals, and description thereof will be omitted.

In the catheter 36, the structure of the relative pressure sensor 7A is slightly different from that of the first embodiment.
Flexible substrate 1 used in sensor section 7A
3 is equal to the width of the pedestal 12. Further, the reference pressure introduction groove 25A formed on the upper surface of the pedestal 12 includes only a portion corresponding to the first region 25a, and a portion corresponding to the second region 25b is omitted. Therefore, the reference pressure introduction groove 25A has a simpler shape (linear shape) than that of the first embodiment. A through hole 37 having a circular cross section is provided at a portion of the flexible substrate 13 corresponding to the base end side of the reference pressure introduction groove 25A. Such a through hole 37 can also be formed using a punching jig or the like, like the through hole 26. Some of the conductor patterns 14 passing through the vicinity of the through hole 26 are formed in a curved shape so as to bypass that portion.

In the catheter 36 configured as described above, the reference pressure introducing groove 25A and the reference pressure chamber 27 communicate with each other through the through-hole 37, so that the atmospheric pressure is reliably generated in the back pressure chamber 31. It is being introduced. Therefore,
Also in the present embodiment, the effects described in (1) to (3) in the first embodiment can be obtained.

The embodiment of the present invention may be modified as follows. In the first and second embodiments, the catheter tube 2 is configured such that a sensor unit module attached to the distal end of the catheter tube 2 is attached to the distal end of the catheter tube 2. Without being limited to this, the cover 2b and the tube main body 2 are made of the same material, for example, like a catheter 38 of another example in FIG.
a may be formed integrally.

The present invention is not limited to the multi-lumen type as in the first and second embodiments and other examples, but may be applied to a single-lumen type. The material of the base 12 is not limited to a metal material such as stainless steel, but may be a ceramic material or a resin material.

A rigid board may be used as a printed wiring board instead of the flexible board 13.
It is also possible to adopt a configuration in which the printed wiring board itself is omitted. That is, the chip support 11 may not only have a two-layer structure but also include only the pedestal 12 (only one member). In that case, a conductor pattern may be formed directly on the upper surface of the pedestal 12 by, for example, a printing method.

When the reference pressure introducing grooves 25, 25A are formed at the interface formed by both layers of the chip support 11, it can be formed not on the upper surface of the pedestal 12 but on the lower surface of the printed wiring board. is there.

The reference pressure introduction path is the chip support 1
It may not be formed at the interface between the two layers, and may be, for example, a hole that is provided so as to extend along the length direction of the pedestal 12.

Next, in addition to the technical ideas described in the claims, the technical ideas grasped by the above-described embodiments are listed below together with their effects. (1) In claim 3, the printed wiring board is a flexible board. Therefore, according to the invention described in the technical idea 1, the sensor unit can be further reduced in size.

(2) In any one of claims 1 to 3, and the technical idea 1, the reference pressure chamber is provided at a position closer to the base end of the tube than the sensor chip. Therefore, according to the invention described in the technical idea 2,
The structure is not complicated, and the sensor unit can be further downsized.

(3) A pressure sensor chip which can be attached near the distal end of the catheter tube, is mounted on the upper surface side of a chip support housed in a cover as a module body, and the pressure sensor chip is In a sensor module in which a reference pressure is introduced into a back pressure chamber defined by a back surface and an upper surface of the chip support, a reference pressure chamber defined on the upper surface side of the chip support in the cover, and the catheter An atmospheric pressure introducing pipe disposed in a tube and communicating the reference pressure chamber with an atmospheric pressure region outside the catheter tube; and communicating the reference pressure chamber and the back pressure chamber formed in the tip support body with each other. A relative pressure sensor module, comprising:

[0045]

As described in detail above, according to the first to third aspects of the present invention, it is an object of the present invention to provide a catheter with a pressure detecting mechanism having a high pressure detecting accuracy and a structure suitable for miniaturization.

In particular, according to the second and third aspects of the invention,
It is possible to provide a sensor unit structure that is simple to manufacture despite its small size.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a part of a sensor unit in a catheter according to a first embodiment of the present invention.

FIG. 2A is a partial cross-sectional view showing a state where the sensor unit of the first embodiment is disposed on a catheter tube, and FIG. 2B is a cross-sectional view taken along line AA in FIG.

FIG. 3 is a perspective view showing a main part of a sensor unit of the first embodiment.

FIG. 4 is a perspective view showing a main part of a sensor unit according to a second embodiment.

FIG. 5A is a partial cross-sectional view showing a state where the sensor unit of the second embodiment is provided in a catheter tube, and FIG. 5B is a cross-sectional view taken along line BB in FIG.

FIG. 6A is a partial cross-sectional view showing a state in which another example of a sensor unit is disposed in a catheter tube, and FIG. 6B is a cross-sectional view taken along line CC in FIG.

FIG. 7 is a partial sectional view showing a sensor section of a conventional catheter.

[Explanation of symbols]

1, 36, 38: catheter with pressure detection mechanism, 2: catheter tube, 3, 4, 5: lumen, 11: chip support, 12: pedestal, 13: flexible substrate as printed wiring board, 17: pressure sensor chip , 25, 2
5A: Reference pressure introduction groove as reference pressure introduction path, 27: Reference pressure chamber, 28: Introduction pipe as atmospheric pressure introduction pipe, 31 ...
Back pressure chamber.

Claims (3)

[Claims] A pressure sensor chip is mounted on an upper surface side of a tip support housed in a lumen of a catheter tube, and is provided in a back pressure chamber defined by a back surface of the pressure sensor chip and an upper surface of the tip support. In a catheter into which a reference pressure is introduced, a reference pressure chamber is defined on the upper surface side of the tip support in the lumen, and an atmospheric pressure introducing pipe communicating the reference pressure chamber with an atmospheric pressure region outside the catheter tube. Is disposed in the catheter tube, and a reference pressure introduction path for communicating the reference pressure chamber and the back pressure chamber is formed in the tip support body. 2. The catheter with a pressure detection mechanism according to claim 1, wherein the tip support has a two-layer structure, and the reference pressure introduction path is formed at an interface between the two layers. 3. The chip support is formed by attaching a printed wiring board to an upper surface of a pedestal, and the reference pressure introducing path is a reference pressure introducing groove formed on the upper surface of the pedestal. The catheter with a pressure detection mechanism according to claim 2.