JP2021151301A - Catheter assembly - Google Patents

Abstract

To provide a catheter assembly capable of suppressing stimulus to a blood vessel caused by the tip of a catheter after extracting an inner needle.SOLUTION: A catheter assembly 10 includes: an inner needle 12 having, on the tip, a needle tip 12a puncturable into a living body; and a catheter 16 having a lumen 16a through which the inner needle 12 is inserted, and arranged outside the inner needle 12. In the catheter 16, when extracting the inner needle 12, a taper part 16b on the tip of the catheter 16 is curved inward.SELECTED DRAWING: Figure 4

Description

The present invention relates to a catheter assembly.

Catheter assemblies are used in constructing introductions for infusions, blood transfusions, etc. in patients. For example, as disclosed in Patent Document 1, the catheter assembly forms a multi-structured needle in which an inner needle is inserted into a catheter (outer needle). In the use of the catheter assembly, the user places the catheter by puncturing the patient with the internal needle of a multi-structured needle, inserting the catheter together with the internal needle into the blood vessel, and then detaching the internal needle from the catheter.

JP-A-2018-143421

However, in the conventional catheter assembly, a sharp portion appears at the tip of the catheter after the inner needle is removed. Therefore, when the catheter moves intermittently in the blood vessel due to the body movement of the patient or the like, the tip of the catheter may gradually damage the inner wall of the blood vessel, causing inflammation or damage.

Therefore, one embodiment aims to provide a catheter assembly capable of suppressing stimulation of a blood vessel by the tip of the catheter after the internal needle is removed.

One aspect of the following disclosure includes an inner needle having a needle tip that can be punctured in a living body at a tip, and a catheter having a lumen through which the inner needle is inserted and arranged outside the inner needle. , In the catheter assembly, where the tip of the catheter bends inward when the inner needle is removed from the catheter.

According to the catheter assembly of the above viewpoint, damage to the blood vessel due to the tip of the catheter after the internal needle is removed is suppressed.

FIG. 1A is a cross-sectional view showing the overall configuration of the catheter assembly according to the first embodiment in a pre-puncture state, and FIG. 1B is an enlarged perspective view of the vicinity of the tip of the catheter assembly of FIG. 1A. 2A is a cross-sectional view of the tip of the catheter after removing the inner needle of FIG. 1A, FIG. 2B is a perspective view of the tip of the catheter of FIG. 2A, and FIG. 2C is near the tip of the catheter assembly of FIG. 1A. It is an enlarged sectional view. It is explanatory drawing of the state in which the catheter assembly of FIG. 1A is punctured into the blood vessel of a living body. It is explanatory drawing of the catheter which removed the inner needle of FIG. It is explanatory drawing of the catheter which concerns on a comparative example. FIG. 6A is a cross-sectional view of the tip of the catheter after removal of the inner needle according to the second embodiment, and FIG. 6B is a perspective view of the tip of the catheter of FIG. 6A. FIG. 7A is a cross-sectional view of the catheter assembly according to the third embodiment in a state before puncture, and FIG. 7B is a cross-sectional view showing a state of deformation of the catheter after removing the inner needle of FIG. 7A. FIG. 8A is a cross-sectional view of the catheter assembly according to the fourth embodiment in a state before puncture, and FIG. 8B is a cross-sectional view showing a state of deformation of the catheter after removing the inner needle of FIG. 8A. FIG. 9A is a cross-sectional view of the catheter assembly according to the fifth embodiment in a state before puncture, and FIG. 9B is a cross-sectional view showing a state of deformation of the catheter after removing the inner needle of FIG. 9A. FIG. 10A is a cross-sectional view of the catheter assembly according to the sixth embodiment in a state before puncture, and FIG. 10B is a cross-sectional view showing a state of deformation of the catheter after removing the inner needle of FIG. 10A. FIG. 11A is a cross-sectional view of the catheter assembly according to the seventh embodiment in a state before puncture, and FIG. 11B is a cross-sectional view showing a state of deformation of the catheter after removing the inner needle of FIG. 11A. FIG. 12A is a cross-sectional view of the catheter assembly according to the eighth embodiment in a state before puncture, and FIG. 12B is a cross-sectional view showing a state of deformation of the catheter after removing the inner needle of FIG. 12A.

Hereinafter, the catheter assembly 10 will be described in detail with reference to the accompanying drawings with reference to suitable embodiments.

(First Embodiment)
As shown in FIGS. 1A and 1B, the catheter assembly 10 according to the present embodiment is used for infusion, blood transfusion, or the like to a patient (living body), and the catheter is punctured, inserted, and indwelled in the patient's body. It is a medical device that constructs an introduction part for chemicals and the like. The catheter assembly 10 may be applied to a relatively short peripheral venous catheter that is inserted into the peripheral vein. Further, the catheter assembly 10 may be applied to a central venous catheter, a PICC, a midline catheter and the like. Further, the catheter assembly 10 is not limited to the intravenous catheter, and may be applied to an arterial catheter such as a peripheral arterial catheter.

The catheter assembly 10 has an inner needle 12, an inner needle hub 14 that holds the inner needle 12 fixedly, a catheter 16 (outer needle) that is arranged outside the inner needle 12, and a catheter hub 18 that holds the catheter 16 fixedly. And.

The catheter assembly 10 constitutes a multi-structured needle 11 in which an inner needle 12 and a catheter 16 are overlapped in order from the inside in a state before use (pre-puncture state). In the pre-puncture state, in the multi-structure needle 11, the needle tip 12a of the inner needle 12 protrudes from the edge 16c of the catheter 16, and the inner needle 12 and the catheter 16 are integrally punctured into the patient's body. Then, the catheter 16 is inserted into the blood vessel 100 (see FIG. 3) while maintaining the puncture state. Then, when the user retracts and removes the inner needle 12 with respect to the catheter 16, the catheter 16 is placed in the blood vessel.

The inner needle 12 is a long body having rigidity capable of puncturing the skin of a living body, and is formed as a tubular body having a lumen 12b formed inside through the skin in the axial direction. A sharp needle tip 12a is formed at the tip of the inner needle 12. The inner needle 12 is not limited to the tubular body, and may be a solid needle having no lumen 12b. Examples of the constituent material of the inner needle 12 include a metal material such as stainless steel, aluminum or an aluminum alloy, titanium or a titanium alloy, or a hard resin or ceramics. The inner needle 12 is fixed to the inner needle hub 14 by an appropriate fixing means such as fusion, adhesion, and insert molding.

The inner needle hub 14 is a member that holds the inner needle 12 in a fixed manner and moves integrally with the inner needle 12. The inner needle hub 14 is detachably attached to the base end of the catheter hub 18 and constitutes a grip portion to be gripped by the user. The inner needle hub 14 is formed in a square cylinder shape, has R-shaped corners so that the user can easily grasp it, and is designed to have a size (thickness and length) that is easy to operate. ..

The outer peripheral surface of the tip of the inner needle hub 14 is formed in a shape (for example, a columnar shape) corresponding to the inner peripheral surface of the catheter hub 18, and the tip of the inner needle hub 14 is inserted into the catheter hub 18. ing. The outer peripheral surface of the inner needle hub 14 is fitted with the inner peripheral surface of the catheter hub 18 with an appropriate frictional force. As a result, the inner needle hub 14 can be easily detached from the catheter hub 18.

The catheter 16 is a tubular member that is flexible and formed to a predetermined length, and is arranged outside the inner needle 12 to partially cover the inner needle 12. Inside the catheter 16, a lumen 16a extending along the axial direction of the catheter 16 into which the inner needle 12 can be inserted and arranged is formed.

At the tip of the catheter 16, a tapered portion 16b formed so as to gradually decrease in wall thickness toward the tip and taper is formed. A sharp edge 16c is formed at the tip of the tapered portion 16b. The inner peripheral surface of the tapered portion 16b of the catheter 16 is formed by a curved surface having a circular cross section along the outer peripheral surface of the inner needle 12 in the state before puncture, and is in contact with the inner needle 12. The inner peripheral surface other than the tip of the catheter 16 has an inner diameter slightly larger than the diameter of the inner needle 12 in order to facilitate the removal of the inner needle 12, and forms a gap slightly separated from the inner needle 12. ..

The catheter 16 is made of an elastic and low-rigidity resin material, and in the initial state before the inner needle 12 is inserted, the tapered portion 16b is curved inward as shown in FIG. 2A. It is shaped into a shape. As shown in FIG. 2B, the tapered portion 16b is curved in the inner peripheral direction in the entire circumferential direction with the edge 16c at the tip inside. In the illustrated example, in the curved state, the edge 16c of the tapered portion 16b is inclined inward with respect to the axial direction of the catheter 16, but the edge 16c is more strongly curved so as to be folded back toward the proximal end side. You may.

When the inner needle 12 is inserted into the lumen 16a of the catheter 16 as described above, the tapered portion 16b is expanded outward by the inner needle 12 to have the shape shown in FIG. 2C. The catheter 16 has the shape shown in FIG. 2C and is punctured into the patient's body. Further, when the inner needle 12 of the catheter 16 is removed after being introduced into the blood vessel 100, the tapered portion 16b is moved inward due to the shape memory (shape retention) of the resin material as shown in FIGS. 2A and 2B. Curve.

Specific examples of the material constituting such a catheter 16 include polyurethane, polyvinyl chloride (PVC), hydrogenated styrene-based thermoplastic elastomer (SEBS), polybutadiene, and silicone rubber. The catheter 16 is integrally formed of the above materials over the entire length. Further, the material constituting the catheter 16 may be a shape memory material such as a shape memory resin.

As shown in FIG. 1A, the base end portion of the catheter 16 is fixed to the tip end portion of the catheter hub 18 by an appropriate fixing means such as fusion, adhesion, and fitting.

The catheter hub 18 is not particularly limited, but is formed of, for example, a thermoplastic resin such as polypropylene, polycarbonate, polyamide, polysulfone, polyarylate, methacrylate, methacrylate-butylene-styrene copolymer and the like.

The catheter hub 18 is a tubular body formed to have a diameter larger than that of the catheter 16, and has a tip taper portion 20 that tapers toward the tip and a tip taper portion 20 that is connected to the tip taper portion 20 and tapers at a gentle angle toward the tip. It has a base end tapered portion 22 that serves as a base. Further, inside the catheter hub 18, an internal space 24 is formed which communicates with the lumen 16a of the catheter 16 and into which the internal needle 12 is inserted.

The tip of the inner needle hub 14 is inserted into the base end of the base end tapered portion 22. The inner peripheral surface of the base end tapered portion 22 is formed in an inner surface shape into which the inner peripheral surface of the tip end portion of the inner needle hub 14 can be fitted. Further, when the catheter 16 and the catheter hub 18 are indwelled, the catheter assembly 10 circulates the infusion solution through the internal space 24. For this reason, the internal space 24 includes a hemostatic valve (not shown) that prevents backflow of blood when the inner needle 12 is punctured, and a plug (not shown) that allows infusion through the hemostatic valve when the connector of the infusion tube is inserted. It may be contained.

The catheter assembly 10 according to the present embodiment is configured as described above, and its operation will be described below.

When performing infusion or blood transfusion to a patient, the user (doctor, nurse, etc.) grasps the inner needle hub 14 of FIG. 1A, and as shown in FIG. 3, holds the multi-structured needle 11 in the pre-puncture state. Puncture into the patient's blood vessel 100. At the time of puncture, the catheter 16 is in contact with and supported by the inner needle 12 near the proximal end of the needle tip 12a. As a result, the relatively flexible catheter 16 is inserted into the blood vessel 100 without causing bending or wrinkling even when it receives a resistance force from a living tissue 102 such as skin or a blood vessel.

In puncture, when the inner needle 12 penetrates the blood vessel wall 104 and enters the blood vessel 100, the user stops inserting the inner needle 12 and advances the catheter 16 with respect to the inner needle 12 while maintaining this position. Perform the operation. At this time, the user retracts the inner needle hub 14 fixed to the catheter hub 18 in the proximal direction, and separates the inner needle hub 14 from the catheter hub 18. The inner needle 12 also retracts integrally with the inner needle hub 14.

As shown in FIG. 4, the inner needle hub 14 is retracted until the inner needle 12 is completely pulled out from the catheter hub 18, and the inner needle 12 is pulled out from the catheter 16. As a result, the catheter assembly 10 shifts to the post-puncture state shown in FIG. In this post-puncture state, the tapered portion 16b of the catheter 16 is curved inward, and the edge 16c of the sharp tapered portion 16b retracts inside the catheter 16. As a result, it is possible to prevent the thin and sharp edge 16c of the tapered portion 16b from coming into contact with the blood vessel wall 104 of the blood vessel 100, and the smooth curved portion comes into contact with the blood vessel wall 104. Therefore, the stimulation of the blood vessel wall 104 by the edge 16c of the catheter 16 can be suppressed, and the inflammation and damage of the blood vessel 100 can be suppressed even when the catheter 16 moves.

On the other hand, in the catheter 116 of the comparative example of FIG. 5, since the tapered portion 116b is not curved, the thin and sharp edge 116c of the tapered portion 116b comes into contact with the blood vessel wall 104. In the catheter 116 of the comparative example, even when a relatively flexible material is used, the stimulation to the blood vessel wall 104 becomes strong, which may cause inflammation or damage to the blood vessel 100.

On the other hand, in the catheter 16 of the present embodiment shown in FIG. 4, since the curved portion of the tapered portion 16b having a large curvature and smoothly curved appears at the tip of the catheter 16, irritation to the blood vessel wall 104 is reduced. Inflammation and damage to blood vessel 100 are suppressed.

The catheter assembly 10 of the present embodiment has the following effects.

The catheter assembly 10 of the present embodiment has an inner needle 12 having a needle tip 12a that can be punctured in the living body at the tip, and a lumen 16a through which the inner needle 12 is inserted, and is arranged outside the inner needle 12. A catheter 16 is provided, and when the inner needle 12 is removed from the catheter 16, the tapered portion 16b at the tip of the catheter 16 curves inward. According to the catheter assembly 10 of the above viewpoint, since the tapered portion 16b at the tip of the catheter 16 after the inner needle 12 is removed is curved inward, the sharp edge 16c is prevented from coming into contact with the blood vessel wall 104. , Damage to the blood vessel 100 by the catheter 16 can be suppressed.

In the catheter assembly 10 described above, the tapered portion 16b of the catheter 16 may be curved toward the inner circumference over the entire circumference. With such a configuration, the contact of the edge 16c of the catheter 16 with the blood vessel wall 104 is prevented over the entire circumferential direction of the catheter 16. Therefore, the user can use the catheter 16 without worrying about the rotation angle of the catheter 16.

In the catheter assembly 10, the tapered portion 16b of the catheter 16 may be curved so that the tip edge 16c faces the proximal end side. In this case, since the sharp edge 16c is housed in the inner back side of the catheter 16, damage to the blood vessel 100 due to the edge 16c can be more reliably prevented.

In the catheter assembly 10 described above, the tapered portion 16b of the catheter 16 may be formed of a material having shape memory. By making the material having shape memory, the edge 16c after the removal of the inner needle 12 is surely curved, so that the damage to the blood vessel 100 by the edge 16c of the catheter 16 is prevented.

In the catheter assembly 10 described above, the tapered portion 16b of the catheter 16 is maintained in the first state (pre-puncture state) extending along the side wall of the inner needle 12 in a state where the inner needle 12 is inserted through the catheter 16. When the inner needle 12 is removed, the catheter 16 shifts to a second state (post-puncture state) curved inward. According to the catheter assembly 10 of the above viewpoint, when the catheter 16 is punctured together with the inner needle 12, the tapered portion 16b of the catheter 16 extends along the inner needle 12, so that the catheter can be smoothly punctured with a small puncture resistance. 16 can be punctured. Further, after the inner needle 12 is removed, the tapered portion 16b of the catheter 16 is curved inward, so that damage to the blood vessel 100 by the catheter 16 can be suppressed.

(Second Embodiment)
As shown in FIGS. 6A and 6B, the catheter assembly 10A according to this embodiment has a catheter 16A. In FIG. 6A, the illustration of the inner needle 12 is omitted. The catheter 16A includes a relatively rigid proximal catheter 26 provided on the proximal side and a flexible distal catheter 28 connected to the distal end of the proximal catheter 26.

The proximal catheter 26 is configured as a tubular member made of a metal material such as stainless steel or a highly rigid material such as a hard resin. Inside the proximal catheter 26, a lumen 26a into which the inner needle 12 can be inserted and placed is formed so as to extend in the axial direction. A mounting portion 26b for mounting the tip catheter 28 is formed at the tip of the proximal catheter 26. The base end portion 28d of the tip catheter 28 is joined to the mounting portion 26b by an appropriate method such as welding, adhesion, or insert molding.

The tip catheter 28 is formed in a tubular shape having a lumen 28a, and is made of a resin material that is more elastic and less rigid than the proximal catheter 26. As the material of the tip catheter 28, the same material as the catheter 16 described with reference to FIG. 1A can be used. On the distal end side of the distal catheter 28, a tapered portion 28b formed so as to gradually decrease in wall thickness toward the distal end is formed, and a sharp edge 28c is formed at the distal end of the tapered portion 28b. ing.

As shown in FIGS. 6A and 6B, in a state where the inner needle 12 (see FIG. 1A) is not inserted, the tapered portion 28b is curved inward over the entire circumference thereof. The tapered portion 28b is curved so that the edge 28c at the tip thereof is folded back toward the proximal end side. When the inner needle 12 (see FIG. 1A) is inserted into such a tip catheter 28, the taper portion 28b is expanded outward while the edge 28c is pushed out toward the tip side, and the taper portion is the same as that of the taper portion 16b in FIG. 2C. It becomes a shape.

After introducing the catheter 16A into the patient's blood vessel 100, when the inner needle 12 (see FIG. 1A) is pulled out, the tapered portion 28b of the tip catheter 28 is curved inward and sharpened as shown in FIGS. 6A and 6B. Edge 28c is housed inside the tip catheter 28.

As described above, in the catheter assembly 10A of the present embodiment, the catheter 16A is composed of the proximal catheter 26 and the distal catheter 28 connected to the distal end side of the proximal catheter 26. The tip catheter 28 is made of a material that is more elastic than the proximal catheter 26 and less rigid than the proximal catheter 26. With such a configuration, the rigidity of the entire catheter 16A is increased, and it becomes easy to puncture the living tissue 102.

(Third Embodiment)
As shown in FIG. 7A, the catheter assembly 10B of this embodiment has a catheter 16B. The catheter 16B includes a tubular catheter body 30 arranged outside the inner needle 12 and a swelling layer 32 that covers the outer peripheral portion of the catheter body 30. The catheter body 30 is made of a flexible resin material, and a cavity 30a through which the inner needle 12 is inserted and arranged is formed in the inner peripheral portion thereof so as to extend in the axial direction. Further, a tapered portion 30b formed tapered toward the distal end side is formed at the distal end portion of the catheter main body 30. A cornered edge 30c is formed at the tip of the tapered portion 30b.

The swelling layer 32 is a layer formed of a material that expands when it comes into contact with moisture or the like, and is formed by applying a swelling gel material to the outer surface of the catheter body 30. The swelling layer 32 does not need to cover the entire outer surface of the catheter body 30, but is formed so as to cover at least the tapered portion 30b and the outer surface in the vicinity thereof. Specific materials of such a swollen layer 32 include sodium polyacrylate, polyethylene glycol, a cellulose-based polymer substance, a polyethylene oxide-based polymer substance, and a maleic anhydride-based polymer substance (for example, methyl vinyl ether-maleine anhydride). Maleic anhydride copolymers such as acid copolymers), block copolymers of acrylamide polymer substances (eg polyacrylamide, polyglycidyl methacrylate-dimethylacrylamide (PGMA-DMAA)), water-soluble nylon, polyvinyl alcohol , Polyvinylpyrrolidone and the like.

An inner needle 12 is inserted and arranged in the lumen 30a of the catheter 16B to form the multi-structured needle 11B of the present embodiment. The catheter 16B is inserted into the living tissue together with the inner needle 12 and used.

After the multi-structure needle 11B is inserted into the blood vessel, the inner needle 12 is removed as shown in FIG. 7B. At that time, since the swelling layer 32 of the catheter 16B expands by coming into contact with the water in the blood, there is a difference in the swelling force between the inner peripheral side and the outer peripheral side of the catheter body 30, and the tip is bent inward. Stress acts. Then, the tapered portion 30b of the catheter body 30 is deformed so as to be curved inward by the expansion force of the swelling layer 32.

As a result, contact of the edge 30c with the blood vessel wall 104 is prevented, and damage to the blood vessel 100 by the catheter 16B is suppressed.

(Fourth Embodiment)
As shown in FIG. 8A, the catheter assembly 10C of this embodiment has a catheter 16C. In FIG. 8A, the illustration of the inner needle 12 is omitted. The catheter 16C includes a tubular catheter body 36 having a cavity 36d formed therein, and a hard layer 34 joined to the inner peripheral surface of the catheter body 36. The catheter body 36 is formed in a cylindrical shape by a soft resin material, and a lumen 36a for inserting and arranging an inner needle 12 (see FIG. 1A) is formed so as to extend in the axial direction on the inner peripheral side thereof. There is. A tapered portion 36b formed tapered toward the tip is formed at the tip of the catheter main body 36, and an edge 36c having a sharp angle is formed at the tip of the tapered portion 36b.

The catheter body 36 of the present embodiment has a cavity 36d formed inside. The hollow portion 36d is formed by connecting from the proximal end side to the inside of the tapered portion 36b. Air can be introduced into the cavity 36d through a port (not shown). Since the catheter body 36 is made of a soft material, it can expand when air is introduced into the cavity 36d.

A hard layer 34 made of a hard resin material having higher rigidity than the resin material constituting the catheter main body 36 is formed on the inner peripheral portion of the catheter main body 36. The hard layer 34 is made of a tubular body having a lumen penetrating in the axial direction inside, and its tip portion 34a is arranged closer to the proximal end side than the tapered portion 36b. That is, the hard layer 34 is formed only in the range closer to the proximal end side than the tapered portion 36b on the inner peripheral surface of the catheter main body 36, and the hard layer 34 is formed on the inner peripheral side of the tapered portion 36b. No. The hard layer 34 and the catheter body 36 are joined so as not to slide in the axial direction, and the hard layer 34 prevents the lumen 36a of the catheter 16C from collapsing.

The catheter 16C as described above is introduced into the blood vessel 100 together with the inner needle 12 (see FIG. 1A), and then is placed in the blood vessel 100 with the inner needle 12 removed. After that, when the user introduces a fluid containing a gas such as air or a liquid such as water into the cavity 36d inside the catheter body 36, the portion not covered with the hard layer 34 expands as shown in FIG. 8B. It transforms like this. As a result, the tapered portion 36b is deformed so as to be curved inward, and the tip portion 34a of the hard layer 34 is deformed so as to be covered by the tapered portion 36b of the soft catheter body 36. Further, the edge 36c of the catheter body 36 retracts inside the catheter 16C, and the tip of the catheter 16C is covered with a smooth curved surface.

As described above, the catheter 16C of the present embodiment also suppresses damage to the blood vessel 100.

(Fifth Embodiment)
As shown in FIG. 9A, the catheter assembly 10D of this embodiment has a catheter 16D. In the catheter 16D, a pair or a plurality of pairs of magnets 38 are arranged in the vicinity of the tapered portion 16b at the tip end. The paired magnets 38 are arranged in a direction in which an attractive force acts on each other, and the attractive force acts in a direction in which the tapered portion 16b is curved inward. One of the paired magnets 38 may be replaced with a ferromagnet that is attracted to the magnet 38 such as iron.

An inner needle 12 is inserted into the lumen 16a of the catheter 16D to form the multi-structured needle 11D of the present embodiment. The catheter 16D is introduced into the patient's blood vessel 100 together with the internal needle 12.

After that, when the inner needle 12 is removed, the tapered portion 16b is deformed so as to be crushed inward by the attractive force of the magnet 38 as shown in FIG. 9B, and the tapered portion 16b is curved inward. As a result, the tip of the catheter 16D is deformed into a smooth curved surface, and the edge 16c can be prevented from coming into contact with the blood vessel wall 104.

As described above, the catheter 16D of the present embodiment also suppresses damage to the blood vessel 100.

(Sixth Embodiment)
As shown in FIG. 10A, the catheter assembly 10E of this embodiment has a catheter 16E. An internal needle 12 is removably inserted into the lumen 16a of the catheter 16E to form the multi-structured needle 11E of the present embodiment. In the catheter 16E, the adhesive resin 40 is applied to the edge 16c at the tip of the tapered portion 16b, and the edge 16c is adhered to the inner needle 12. The adhesive resin 40 is ruptably connected by a load in the pulling direction when the inner needle 12 is pulled out.

As shown in FIG. 10B, when the inner needle 12 is removed, the edge 16c of the tapered portion 16b is moved by the adhesive resin 40 so as to follow the inner needle 12 and be pulled toward the proximal end side. At that time, the tapered portion 16b is plastically deformed, and the tapered portion 16b is deformed so as to be curved inward. As a result, even after the inner needle 12 is removed, the tapered portion 16b is maintained in an inwardly curved shape, and the tip portion of the catheter 16E is deformed into a smooth curved surface.

As described above, the catheter 16E of the present embodiment also suppresses damage to the blood vessel 100.

(7th Embodiment)
As shown in FIG. 11A, the catheter assembly 10F of this embodiment has a catheter 16. The catheter 16 is shaped so that the tapered portion 16b at the tip is curved inward. The catheter 16 is similar to the catheter 16 of FIG. 2A.

The inner needle 12A has a recess 12c formed on the outer peripheral portion of the portion corresponding to the tapered portion 16b of the catheter 16. The recess 12c is formed in an annular shape over the entire circumferential direction of the inner needle 12A. The end surface 12d on the tip end side of the recess 12c is formed so as to be cut off substantially perpendicular to the axial direction of the inner needle 12A. Due to the shape-retaining property of the catheter 16, an inwardly curved tapered portion 16b is inserted into the recess 12c. The multi-structured needle 11F of the present embodiment is configured by such an inner needle 12A and a catheter 16.

When the inner needle 12A is removed, the edge 16c of the catheter 16 comes into contact with the end surface 12d on the distal end side of the recess 12c and is caught, and acts to pull the edge 16c together with the inner needle 12A. As a result, as shown in FIG. 11B, the tapered portion 16b is plastically deformed and curved inward. Then, a smooth curved surface is formed at the tip of the catheter 16 to prevent the edge 16c from coming into contact with the blood vessel wall 104.

In the present embodiment, even when the resin material constituting the catheter 16 becomes familiar with the inner needle 12A and the shape memory is deteriorated, the tapered portion 16b is surely curved inward when the inner needle 12A is removed. Can be made to.

(8th Embodiment)
As shown in FIG. 12A, the catheter assembly 10G of this embodiment has a catheter 16G. The catheter 16G is a catheter having a tapered portion 16b on the distal end side and an edge 16c formed on the distal end of the tapered portion 16b, and a lumen 16a through which the inner needle 12 is inserted is formed inside. The inner needle 12 is inserted into the catheter 16G to form the multi-structured needle 11G of the present embodiment.

The catheter 16G has a core material 42 made of a shape memory alloy built therein. The core material 42 is made of a wire rod of a shape memory alloy extending from the inside of the tapered portion 16b of the catheter 16G toward the proximal end side, and is shaped so that the tapered portion 16b is curved toward the inner peripheral side. The core material 42 is arranged at regular intervals in the circumferential direction of the catheter 16G, and is composed of a plurality of wire rods extending in the axial direction. The core material 42 is formed by embedding it in a resin member constituting the catheter 16G by, for example, insert molding or the like.

The core material 42 is not limited to the wire rods separated (isolated) in the circumferential direction, and may be woven into a mesh shape. Further, the material constituting the core material 42 is not limited to the shape memory alloy, and may be composed of various spring alloys exhibiting spring elasticity.

As shown in the figure, when the inner needle 12 is inserted, the catheter 16G is aligned in the direction of the outer peripheral surface of the inner needle 12, and the tapered portion 16b is kept in a state where the edge 16c is directed toward the tip.

As shown in FIG. 12B, when the inner needle 12 is removed after introducing the catheter 16G into the blood vessel 100, the core material 42 is deformed in a preformed direction. Due to the deformation of the core material 42, the tapered portion 16b of the catheter 16G is curved inward. Then, the edge 16c moves to the inner peripheral side, and the tip of the catheter 16G is deformed into a smooth curved surface.

As described above, the catheter 16G of the present embodiment also suppresses damage to the blood vessel 100.

Although the present invention has been described above with reference to preferred embodiments, it goes without saying that the present invention is not limited to the above embodiments and various modifications can be made without departing from the spirit of the present invention. stomach.

10, 10A-10G ... Catheter assembly 12, 12A ... Inner needle 12a ... Needle tip 12b, 16a, 26a, 30a, 36a ... Cavity 14 ... Needle hub 16, 16A-16E, 16G ... Catheter 26 ... Base catheter 28 … Tip catheter

Claims (7)

An inner needle that has a needle tip that can be punctured in the living body at the tip,
A catheter having a lumen through which the inner needle is inserted and located outside the inner needle is provided.
A catheter assembly in which the tip of the catheter bends inward when the inner needle is removed from the catheter. The catheter assembly according to claim 1, wherein the tip of the catheter is curved inwardly over the entire circumference. The catheter assembly according to claim 1 or 2, wherein the tip of the catheter is curved and faces the proximal end side. The catheter assembly according to any one of claims 1 to 3, wherein the catheter has a proximal catheter and an distal catheter connected to the distal end side of the proximal catheter, and the distal end thereof. A catheter assembly made of a material that is more elastic than the proximal catheter and less rigid than the proximal catheter. The catheter assembly according to any one of claims 1 to 3, wherein the tip of the catheter is formed of a material having shape memory. The catheter assembly according to any one of claims 1 to 5, wherein the tip of the catheter extends along the side wall of the inner needle while the inner needle is inserted into the catheter. A catheter assembly that is kept in one state and transitions to a second state that curves inward of the catheter when the inner needle is removed. The catheter assembly according to claim 6, wherein the first state and the second state can be repeated.

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