JP2016002346A - catheter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catheter which is excellent in productivity and has a pressure sensor reliably fixed.SOLUTION: A catheter has: a sensor which can measure pressure by using light; and an end chip 30 where a sensor housing hole that is provided with an optical fiber 41 connected to the sensor and a first opening at a chip distal end 30a and houses the sensor and a through-hole that is stretched to a second opening at a chip proximal end to be a proximal end from the connection part connected to the sensor housing hole and passes the optical fiber therethrough are formed and which is formed from thermoplastic resin. The optical fiber is pressured and fixed to the end chip inside the through-hole.

Description

  The present invention relates to a catheter, and more particularly, to a catheter with a pressure sensor having a pressure sensor attached to the tip.

  In recent years, in the medical field, catheters are frequently used for various treatments and examinations. For example, an intra-aortic balloon pumping method (IABP method) is performed as a treatment for lowering cardiac function, in which a balloon catheter is inserted into the aorta, and the balloon is inflated and deflated according to the heart beat to assist the cardiac function. It has been broken.

  In addition, in order to accurately detect the pulsation of a patient, a catheter is proposed in which a pressure sensor (electric signal conversion method) is attached to the distal end of the catheter, and the blood pressure at the distal end of the catheter is detected as an electrical signal. (For example, Patent Document 1). Also, a pressure sensor using light as a pressure sensor attached to the distal end of the catheter has been proposed (for example, Patent Document 2).

JP-A-9-2225022 JP 2010-233883 A

  However, the conventional catheter with a pressure sensor has a problem that it takes time to fix the sensor and the tip because the fixing method uses an adhesive. In particular, the surface of the optical fiber connected to the pressure sensor using light tends to be hard to adhere, and the usable adhesive may be limited from the viewpoint of biological safety and the like. Therefore, fixing using an adhesive has a problem in terms of productivity, such as requiring a careful manual manufacturing process.

  The present invention has been made in view of such a situation, and an object thereof is to provide a catheter having a pressure sensor which is excellent in productivity and securely fixed.

In order to achieve the above object, a catheter according to the present invention comprises:
A sensor capable of measuring pressure using light;
An optical fiber connected to the sensor, a sensor receiving hole having a first opening at the distal end of the tip, which is the distal end, and the tip being the proximal end from the connecting portion connected to the sensor receiving hole A through hole extending to the second opening at the proximal end and passing through the optical fiber, and having a tip formed of a thermoplastic resin,
The optical fiber is fixed by being crimped to the tip end in the through hole.

  In the catheter according to the present invention, the optical fiber and the sensor connected thereto are fixed by crimping the optical fiber in the through hole of the thermoplastic tip, and therefore an adhesive is used to fix the sensor. Compared with the conventional method to be used, it is possible to fix easily and surely.

Further, for example, the catheter according to the present invention may further include a balloon membrane in which a balloon distal end that is a distal end is fixed to the outer peripheral surface of the tip by heat fusion,
The fiber fixing portion that fixes the optical fiber and the tip tip may be disposed inside the balloon fixing portion to which the balloon distal end and the tip tip are fixed.

  By arranging the fiber fixing portion inside the balloon fixing portion, the through hole is simultaneously provided when the balloon film is fixed to the outer peripheral surface of the tip by heat fusion (that is, the balloon fixing portion is formed). It is possible to crimp and fix the tip tip and the optical fiber (that is, to form a fiber fixing portion), and such a catheter has excellent productivity.

Further, for example, the tip chip may be formed with a guide wire insertion hole extending in parallel with the sensor accommodation hole and the through hole,
An inner tube distal end that is a distal end of an inner tube is connected to the guide wire insertion hole,
An outer tube distal end, which is a distal end of the outer tube, may be connected to a balloon proximal end, which is the proximal end of the balloon membrane.

  Further, for example, the catheter according to the present invention has a fiber insertion hole through which the optical fiber is inserted so as to be axially movable, and is disposed in the sensor receiving hole and closer to the through hole than the sensor. A positioning member may be further included.

  Such a catheter can arrange and fix a sensor reliably and easily at a predetermined position of the sensor accommodation hole by arranging a positioning member.

In addition, for example, the catheter according to the present invention includes a tip partition membrane that seals the first opening of the sensor accommodation hole,
You may further have the gel-like substance with which the said sensor accommodation hole is filled so that the said sensor may be covered.

FIG. 1 is a schematic sectional view of a catheter according to an embodiment of the present invention. FIG. 2 is a perspective view of the tip chip shown in FIG. FIG. 3 is a cross-sectional view of the tip shown in FIG. 4 is a partial cross-sectional view of the proximal end of the balloon membrane shown in FIG. FIG. 5 is a conceptual diagram illustrating a catheter manufacturing process. FIG. 6 is a cross-sectional view of the distal tip included in the catheter according to the second embodiment of the present invention.

  Hereinafter, a catheter according to the present invention will be described based on an embodiment shown in the drawings.

First Embodiment FIG. 1 is a schematic cross-sectional view of a balloon catheter 20 according to an embodiment of the present invention. The balloon catheter 20 has a balloon membrane 22 that expands and contracts in accordance with the heart beat, and is used for an intra-aortic balloon pumping method. The balloon film 22 is a thin film having a film thickness of about 50 to 150 μm. The material of the thin film is not particularly limited, but is preferably a material excellent in bending fatigue resistance, and is made of, for example, polyurethane.

  The outer diameter and length of the balloon membrane 22 are determined according to the inner volume of the balloon membrane 22 that greatly influences the assisting effect on the cardiac function, the inner diameter of the arterial blood vessel, and the like. The inner volume of the balloon membrane 22 is not particularly limited, but is 20 to 50 cc. The outer diameter of the balloon membrane 22 is preferably 12 to 16 mm when expanded, and the length is preferably 150 to 250 mm.

  The balloon distal end 22a, which is the distal end of the balloon membrane 22, is fixed to the outer peripheral surface of the tip 30 by heat fusion. The tip 30 will be described in detail later.

  A balloon proximal end 22 b that is a proximal end of the balloon membrane 22 is fixed to an outer peripheral surface of an outer tube distal end 24 a that is a distal end of the outer tube 24. A pressure fluid conduction path 29 is formed inside the outer tube 24, and the pressure fluid is introduced and led out into the balloon membrane 22 through the pressure fluid conduction path 29. Thereby, the balloon membrane 22 is inflated and deflated. The balloon membrane 22 and the outer tube 24 can be fixed by heat fusion or adhesion using an adhesive, but is not particularly limited.

  An inner tube 23 passes through the outer tube 24. The inner tube 23 extends in the axial direction inside the distal tip 30, the balloon membrane 22, the outer tube 24 and the branch portion 50, and inside the inner tube 23, the inside of the balloon membrane 22 and the inside of the outer tube 24. A wire passage 28 is formed so as to be separated from the pressure fluid passage 29 formed in the above. The wire passage 28 communicates with the second port 53 of the branch portion 50.

  The wire passage 28 is used as a lumen through which the guide wire is inserted when the balloon catheter 20 is inserted into the artery. By using the guide wire, the balloon catheter 20 can be smoothly inserted into the artery, and the balloon membrane 22 near the distal end can be quickly placed at the target position. The balloon membrane 22 is inserted into the artery while being wound around the inner tube 23 positioned in the balloon membrane 22.

  Although the fixing method of the outer tube 24 and the inner tube 23 is not particularly limited, for example, the outer tube 24 and the inner tube 23 can be fixed by an adhesive. By fixing the outer tube 24 and the inner tube 23 with an adhesive, the flow resistance of the pressure fluid conduction path 29 in the outer tube 24 is lowered, and the responsiveness of the balloon membrane 22 is improved. It does not specifically limit as an adhesive agent used for fixation, Adhesives, such as a cyanoacrylate type adhesive agent and an epoxy-type adhesive agent, can be used, It is especially preferable to use a cyanoacrylate type adhesive agent.

  As shown in FIG. 4, the outer tube distal end 24a may be formed with an engaging portion 24aa for engaging the inner tube 23 with the outer tube 24. The engaging portion 24aa is formed by forming a notch extending in the circumferential direction and closing both ends in the outer tube 24 located in the balloon, and pushing the tube wall on the distal end side from the notch in the inner diameter direction. Can be formed. The inner tube 23 passes through the outside of the engaging portion 24aa and comes out of the outer tube 24 to the outside of the outer tube 24, and comes into contact with the outer peripheral surface of the tube wall in the engaging portion 24aa pushed in the inner diameter direction. By doing so, the outer tube distal end 24a is engaged.

  The outer diameter of the inner tube 23 is not particularly limited, but is preferably 0.5 to 1.5 mm, and preferably 30 to 60% of the inner diameter of the outer tube 24. In this embodiment, the outer diameter of the inner tube 23 is substantially the same along the axial direction. The inner tube 23 is made of, for example, a synthetic resin tube such as polyurethane, polyvinyl chloride, polyethylene, nylon, polyether ether ketone (PEEK), a nickel titanium alloy thin tube, a stainless steel thin tube, or the like. Further, when the inner tube 23 is formed of a synthetic resin tube, a stainless steel wire or the like may be embedded.

  Although the material which comprises the outer tube | pipe 24 is not specifically limited, For example, the outer tube | pipe 24 is comprised with synthetic resins, such as a polyurethane, a polyvinyl chloride, a polyethylene terephthalate, a polyamide, and stainless steel wire etc. are embed | buried in these. May be. The inner diameter and wall thickness of the outer tube 24 are not particularly limited, but the inner diameter is preferably 1.5 to 4.0 mm, and the wall thickness is preferably 0.05 to 0.4 mm. The length of the outer tube 24 is preferably 300 to 800 mm.

  As shown in FIG. 1, a branch portion 50 is connected to the proximal end of the outer tube 24. The branch portion 50 is formed separately from the outer tube 24 and is connected to the outer tube 24 by means such as heat fusion or adhesion. The branch portion 50 includes a first passage 52 in which the first port 51 is formed and a second passage 54 in which the second port 53 is formed. The first port 51 communicates with the pressure fluid communication path 29, and pressure fluid is introduced and led out to the pressure fluid communication path 29 via the first port 51. Further, the second port 53 communicates with the wire passage 28 in the inner tube 23.

  The first port 51 is connected to a pump device (not shown), and the pressure fluid is introduced and led out by the pump device, whereby the balloon membrane 22 is inflated and deflated in accordance with the heartbeat. Can do. The pressure fluid introduced into the balloon membrane 22 and the pressure fluid communication path 29 is not particularly limited, but helium gas having a small viscosity and mass so that the balloon membrane 22 is quickly expanded and contracted according to the driving of the pump device. Is used.

  In addition to the first port 51 and the second port 53, the branch port 50 is formed with a third port 55. The optical fiber 41 is drawn out from the third port 55. However, the fluid inside the first passage 52 and the second passage 54 does not leak to the outside from the third port 55.

  An optical connector 42 is connected to the proximal end of the optical fiber 41. A blood pressure measuring device (not shown) is connected to the optical connector 42. The pump device is controlled on the basis of fluctuations in blood pressure measured by this blood pressure measuring device, and the balloon membrane 22 is inflated and deflated in a short cycle of 0.4 to 1 second corresponding to the pulsation of the heart.

  A cylindrical tip 30 is attached to the distal end of the balloon catheter 20. As shown in FIG. 2, a tip distal end 30a, which is a distal end of the tip tip 30, has a flat surface 30aa to which a tip partition wall film 49 is bonded, and a predetermined inclination angle with respect to the flat surface 30aa. An inclined surface 30ab that is inclined is formed. A guide wire insertion hole 36 is opened in the inclined surface 30ab. By opening the guide wire insertion hole 36 in the inclined surface 30ab, the opening area can be increased, and the operator who handles the balloon catheter 20 can easily pass the guide wire.

  As shown in FIG. 3, which is an enlarged cross-sectional view around the distal tip 30, a sensor accommodating hole 34 for accommodating the pressure sensor 40, a through hole 32 for passing the optical fiber 41, and a guide wire are inserted into the distal tip 30. A hole 36 is formed. The sensor accommodation hole 34 includes a first opening 34 a at the tip distal end 30 a, and the first opening 34 a is sealed with a tip partition wall film 49. The tip partition wall film 49 has a flexibility capable of transmitting the pressure outside the tip chip 30 to the inside of the sensor accommodation hole 34. The tip partition wall film 49 is composed of, for example, a polyurethane film having a film thickness of about 2 to 20 μm, a silicone film, a polyamide elastomer film, a polyester elastomer film, a polyethylene film, or a polypropylene film.

An optical fiber 41 is connected to the pressure sensor 40 accommodated in the sensor accommodation hole 34. The pressure sensor 40 connected to the distal end of the optical fiber 41 is a sensor that detects pressure using a path difference of light transmitted through the optical fiber 41. Since the blood pressure of the blood located outside the distal tip 30 is transmitted to the space where the pressure sensor 40 is disposed via the distal partition wall film 49, the pressure sensor 40 can detect the blood pressure of the patient. it can.
As the pressure sensor 40, for example, those described in JP-T-2008-524606, JP-A-2000-35369 and the like can be used.

  A positioning member 45 is provided in the sensor housing hole 34. The positioning member 45 is disposed in the sensor receiving hole 34 and closer to the through hole 32 (proximal end side) than the pressure sensor 40. The positioning member 45 is formed with a fiber insertion hole 45a through which the optical fiber 41 is inserted. In the present embodiment, the optical fiber 41 and the positioning member 45 are not directly fixed to each other, and the fiber insertion hole 45a allows the optical fiber 41 to be inserted so as to be movable in the axial direction. In addition, the positioning member 45 may be fixed to the tip chip 30 with an adhesive or the like, or may simply be inserted into the sensor accommodation hole 34 from the first opening 34a.

  The sensor accommodation hole 34 is filled with a gel substance 48 so as to cover the pressure sensor 40. In this embodiment, the gel-like substance 48 is filled in the space from the positioning member 45 to the tip partition wall film 49, but is not limited to this, and the gel-like substance 48 is filled up to the connection part 32 a of the through hole 32. May be.

  The through hole 32 in the tip tip 30 continues from the connection portion 32a connected to the proximal end of the sensor receiving hole 34 to the second opening formed in the tip proximal end 30b which is the proximal end of the tip tip 30. Yes. The through hole 32 allows the optical fiber 41 extending from the pressure sensor 40 and passing through the fiber insertion hole 45a of the positioning member 45 to pass from the connection portion 32a to the second opening 32b. The through hole 32 has a smaller inner diameter than the sensor housing hole 34, and the pressure sensor 40 and the positioning member 45 cannot enter the through hole 32.

  The optical fiber 41 is fixed by being crimped to the tip tip 30 in the through hole 32. A part of the proximal end side of the through-hole 32 has a smaller inner diameter than the connection part 32 a located on the distal end side, and this part fixes the optical fiber 41 and the tip chip 30. Is configured. In the connection part 32a, a gap is formed between the inner wall of the through hole 32 and the optical fiber 41. However, in the fiber fixing part 60, the inner wall of the through hole 32 and the optical fiber 41 are in close contact with each other.

  The fiber fixing part 60 is disposed inside the balloon fixing part 62 to which the balloon distal end 22a and the tip end 30 are fixed. The fiber fixing portion 60 is formed by covering the outer side of the balloon distal end 22a with a heat-shrinkable tube and thermally fusing the balloon distal end 22a to the tip 30 to form the balloon fixing portion 62. It is formed by narrowing a part of the through-hole 32 located inside 60.

  The guide wire insertion hole 36 extends in parallel with the sensor receiving hole 34 and the through hole 32 connected thereto, and penetrates the tip tip 30 in the axial direction from the tip distal end 30a to the tip proximal end 30b. . An inner tube distal end 23 a that is a distal end of the inner tube 23 is inserted into the proximal end side of the guide wire insertion hole 36, and the guide wire insertion hole 36 communicates with the wire passage 28 in the inner tube 23. doing. The inner tube distal end 23a is fixed to the guide wire insertion hole 36 by means such as heat fusion or adhesion.

  The optical fiber 41 is drawn into the balloon membrane 22 from the second opening 32b formed in the tip proximal end 30b. Inside the balloon membrane 22, the optical fiber 41 is fixed to the outer peripheral portion of the inner tube 23 by a heat shrinkable tube 27.

  The tip 30 is made of a thermoplastic resin so that the optical fiber 41 in the through hole 32 can be crimped and fixed by deformation due to heat. The material of the tip 30 is not particularly limited, and is composed of, for example, polyurethane, polyethylene, polypropylene, polyamide or the like.

  The positioning member 45 disposed in the sensor housing hole 34 can be made of a thermoplastic resin such as polyurethane, polyamide, or polyester. The positioning member 45 may be made of a highly rigid material such as metal or ceramics. In this case, for example, the positioning member 45 is made of stainless steel, iron, aluminum, nickel titanium, glass, or the like. Examples of the gel substance 48 filled in the sensor accommodation hole 34 include silicone gel, polyacrylamide gel, and polyethylene oxide gel.

  Below, the manufacturing method of the balloon catheter 20 is demonstrated. In the description of the manufacturing method, the assembly method in the vicinity of the distal end of the balloon catheter 20 will be mainly described. About the manufacturing method of another part, since it is the same as that of a well-known method, description is abbreviate | omitted.

  FIG. 5 is a conceptual diagram illustrating a method for manufacturing the balloon catheter 20. As shown in FIG. 5A, in the manufacture of the balloon catheter 20, a tip tip 130 before pressure bonding is prepared, and a pressure sensor 40 and a positioning member 45 through which an optical fiber 41 connected to the pressure sensor 40 is inserted are provided. Is housed in the sensor housing hole 34.

  The positioning member 45 is installed by being pushed from the first opening 34 a to the back of the sensor accommodation hole 34 of the tip chip 130. The optical fiber 41 passes through the through hole 132 and is drawn out from the second opening 132b of the tip proximal end 130b. The pressure sensor 40 is positioned at a predetermined position in the sensor housing hole 34 by pulling the optical fiber 41 toward the proximal end side. In addition, it is preferable that the through hole 132 in the distal end tip 130 before the crimping has an inner diameter of about 1.1 to 4 times the diameter of the optical fiber 41.

  When the first opening 34a is closed with the tip partition wall film 49 in a later step and the pressure sensor 40 is arranged in a sealed system, the positioning member 45 should not be bonded to the tip chip 30. When the positioning member 45 and the tip chip 30 are bonded, a dead space is generated on the proximal end side of the positioning member 45, which may adversely affect the detection accuracy of the pressure sensor 40.

  Next, as shown in FIG. 5B, the distal tip 130, the inner tube 23 and the balloon membrane 22 are fixed. In this step, first, the inner tube distal end 23 a is inserted into the guide wire insertion hole 36 of the tip tip 30. Furthermore, the balloon distal end 22a is installed on the outer peripheral surface near the proximal end of the tip tip 130, and the tip tip 130 is covered with the heat-shrinkable tube 64 and heated from the outside of the balloon distal end 22a. The balloon film 22 is heat-sealed to the tip chip 130. As a result, the thermoplastic distal tip 130 is slightly deformed, resulting in the distal tip 30 in which the optical fiber 41 is fixed in the through hole 32.

  Specifically, when the heat shrinkable tube 64 is heated and contracted, the inner diameter of the through hole 132 of the tip tip 130 is reduced to form the fiber fixing portion 60, and the deformed tip tip 30 has an optical fiber. 41 is in a fixed state by being crimped inside the through hole 32. Further, when the heat shrinkable tube 64 is heated and contracted, the outer peripheral surface of the tip tip 130 and the balloon proximal end 22b are heat-sealed, and the balloon fixing portion 62 is formed.

  When the balloon film 22 is heat-sealed and the optical fiber 41 is pressure-bonded, the guide wire insertion hole 36 extending in parallel with the through-hole 32 has an inner tube of the inner tube 23 usually made of a hard material. Since the distal end 23a is inserted, it is possible to prevent a problem that the guide wire insertion hole 36 is crushed in the heat fusion and pressure fixing process.

  Finally, after filling the sensor containing hole 34 with the gel substance 48 so as to cover the pressure sensor 40, the tip partition wall film 49 is formed on the flat surface 30aa of the tip distal end 30a so as to close the first opening 34a. By fixing, the assembly of the distal end portion of the balloon catheter 20 is completed. The filling of the gel substance 48 and the fixing of the tip partition wall film 49 may be performed before the heat-sealing / crimping process.

  In the balloon catheter 20 according to the present embodiment, the optical fiber 41 is fixed by being crimped into the through hole 32 in the distal tip 30, so that the optical fiber 41 is fixed using an adhesive compared to the conventional method. Realize reliable and reliable fixation. With the balloon catheter 20 that fixes the optical fiber 41 by pressure, the optical fiber 41 can be reliably fixed to the distal end chip 30 even when the optical fiber 41 that is coated with polyimide and is difficult to adhere to the adhesive is used. Further, since the tip tips 130 and 30 are made of a thermoplastic resin, and the tip tip 130 is deformed by heating and is fixed by crimping, an excessive force is not applied to the optical fiber 41 at the time of fixing. It is possible to prevent the optical fiber 41 from being damaged during the manufacturing. In addition, in the fixation of the optical fiber 41 and the tip chip 30, in addition to the fixation by pressure bonding, a fixing method of bonding to the tip chip 30 via the positioning member 45 or directly may be used in combination.

  In addition, the balloon catheter 20 according to this embodiment in which the fiber fixing portion 60 is disposed inside the balloon fixing portion 62 can be used when the balloon membrane 22 is heat-sealed to the tip 30 using the heat-shrinkable tube 64. Since the fiber 41 can be pressed and fixed at the same time, the manufacturing is easy and the productivity is excellent.

  Further, by using the positioning member 45, the pressure sensor 40 can be easily fixed to a desired position. In addition, since it is not necessary to bond the positioning member 45 to the inner wall of the sensor housing hole 34, and it is not necessary to bond the optical fiber 41 to the positioning member 45, the number of bonding points is small and the manufacturing is easy and the reliability is high. .

Second Embodiment The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention. FIG. 6 is an enlarged cross-sectional view showing the vicinity of the distal end of the balloon catheter 220 according to the second embodiment of the present invention. In the balloon catheter 220, the optical fiber 41 is crimped and fixed in the through hole 232 of the tip tip 230, and the basic features are the same as those of the balloon catheter 20 according to the first embodiment. explain.

  In the balloon catheter 220, no positioning member or gel-like substance is disposed in the sensor accommodation hole 234 of the distal tip 230. Further, the tip partition wall film is not provided at the tip distal end 230a of the tip tip 230, and the first opening 234a of the sensor accommodation hole 234 communicates with the outside. Thus, the pressure sensor 40 of the balloon catheter 220 may be held in a state exposed to the outside. In the balloon catheter 220, as in the balloon catheter 20 according to the first embodiment, the optical fiber 41 is fixed by being pressed into the through hole 232 in the distal tip 230, so that the optical fiber 41 and the pressure sensor 40 are fixed. Since it is highly reliable and has a very simple structure with few adhesion points, it is easy to manufacture.

DESCRIPTION OF SYMBOLS 20 ... Balloon catheter 22 ... Balloon membrane 23 ... Inner tube 24 ... Outer tube 30 ... Tip tip 32 ... Through hole 34 ... Sensor accommodation hole 36 ... Guide wire insertion hole 40 ... Pressure sensor 41 ... Optical fiber 45 ... Positioning member 60 ... Fiber Fixing part 62 ... Balloon fixing part

Claims (5)

A sensor capable of measuring pressure using light;
An optical fiber connected to the sensor, a sensor receiving hole having a first opening at the distal end of the tip, which is the distal end, and the tip being the proximal end from the connecting portion connected to the sensor receiving hole A through hole extending to the second opening at the proximal end and passing through the optical fiber, and having a tip formed of a thermoplastic resin,
The catheter, wherein the optical fiber is fixed by being crimped to the distal tip within the through hole. The balloon distal end, which is the distal end, further has a balloon membrane fixed to the outer peripheral surface of the tip by heat fusion,
2. The fiber fixing portion for fixing the optical fiber and the tip tip is disposed inside a balloon fixing portion for fixing the balloon distal end and the tip tip. Catheter. The tip chip is formed with a guide wire insertion hole extending in parallel with the sensor accommodation hole and the through hole,
An inner tube distal end that is a distal end of an inner tube is connected to the guide wire insertion hole,
The catheter according to claim 2, wherein an outer tube distal end, which is a distal end of an outer tube, is connected to a balloon proximal end, which is the proximal end of the balloon membrane.   A fiber insertion hole through which the optical fiber is inserted so as to be axially movable is formed, and further includes a positioning member disposed in the sensor accommodation hole and closer to the through hole than the sensor. The catheter according to any one of claims 1 to 3. A tip partition wall film that seals the first opening of the sensor housing hole;
The catheter according to any one of claims 1 to 4, further comprising a gel substance filled in the sensor accommodation hole so as to cover the sensor.

Images