JP2018143421A - Catheter assembly - Google Patents

Abstract

There is provided a catheter assembly capable of reducing mechanical irritation to a blood vessel when the catheter is inserted into a blood vessel while having appropriate rigidity at the time of puncturing. A catheter assembly includes an inner needle, an inner catheter, an outer catheter, and a catheter hub that holds the outer and inner catheters. The inner needle 12 can be retracted relative to the outer catheter 30 and removed from the catheter hub 18. Further, the inner catheter 20 and the outer catheter 30 can move relative to each other in the longitudinal direction based on the retreat of the inner needle 12. [Selection] Figure 1

Description

  The present invention relates to a catheter assembly having a multi-structure catheter.

  A catheter assembly is used when constructing an infusion part or a transfusion part in a patient. For example, as disclosed in Patent Document 1, the catheter assembly forms a multi-structure needle in which an inner needle is inserted into a catheter (outer needle). In using the catheter assembly, the user punctures the patient with a multi-structure needle, advances the catheter relative to the inner needle, inserts the catheter into the blood vessel, and then disengages the inner needle from the catheter. Detained.

JP 2008-43445 A

  By the way, this type of catheter assembly may cause inflammation, damage, and the like due to the tip of the catheter rubbing the inner wall of the blood vessel when the catheter is inserted into the blood vessel. Therefore, it is conceivable to make the catheter more flexible to suppress inflammation and damage. However, if the catheter is made flexible in this way, the catheter can easily receive the resistance force of the living tissue when the multi-structure needle is punctured. Another inconvenience arises that it becomes difficult to enter the bent blood vessel.

  The present invention has been made in view of the above circumstances, and is a catheter set that can reduce mechanical irritation to a blood vessel when the catheter is inserted into a blood vessel while having appropriate rigidity at the time of puncture. The purpose is to provide a solid.

  In order to achieve the above object, a catheter assembly according to the present invention includes an inner needle, an inner catheter disposed outside the inner needle, an outer catheter disposed outside the inner catheter, and the inner And a catheter hub for fixing and holding the outer catheter, wherein the inner needle is retractable relative to the outer catheter and can be removed from the inner catheter and the outer catheter, and the inner catheter and the outer catheter The catheters are characterized in that they can move relative to each other in the longitudinal direction of the inner needle.

  According to the above, the inner needle, the inner catheter, and the outer catheter of the catheter assembly constitute a multi-structure needle that overlaps each other. For this reason, the inner catheter supports the outer catheter from the inside to obtain appropriate rigidity as the whole catheter, and even when the outer catheter receives the resistance force of the living tissue at the time of puncturing, the bending can be suppressed. Therefore, the catheter can be smoothly inserted into the blood vessel. Further, since the inner catheter and the outer catheter can move relative to each other in the longitudinal direction based on the retraction of the inner needle, the influence of the inner catheter can be suppressed before the outer catheter is inserted into the blood vessel. Thus, the catheter assembly can reduce the mechanical irritation to the blood vessels and better place the catheter.

  In this case, the inner catheter is preferably movable relative to the outer catheter based on the retraction of the inner needle.

  In this way, the inner catheter can move relative to the outer catheter based on the retraction of the inner needle, so that the outer catheter can be favorably supported by the inner catheter until the inner needle retracts.

  Further, the catheter assembly is capable of transitioning between a first state in which the distal end of the inner catheter contacts the distal end of the outer catheter and a second state in which the distal end of the inner catheter is separated from the distal end of the outer catheter. There should be.

  As described above, since the catheter assembly can be shifted between the first state and the second state, the support and release of the distal end of the outer catheter by the distal end of the inner catheter can be easily switched.

  Further, one of the inner and outer catheters may be fixed so as not to move relative to the catheter hub, and the other of the inner and outer catheters may be fixed to the catheter hub via an elastic portion.

  As described above, one of the inner and outer catheters is fixed so as not to move relative to the catheter hub, and the other is fixed via the elastic portion, so that the elastic force due to the expansion and contraction of the elastic portion is applied to the other. be able to. This makes it possible to easily carry out relative movement of the other to the other.

  In addition to the above configuration, the elastic portion may have a restoring force in a direction in which the distal end of the inner catheter and the distal end of the outer catheter are separated from each other in the first state.

  In this way, the elastic portion has a restoring force in a direction in which the distal end of the outer catheter and the distal end of the inner catheter are separated from each other in the first state, so that the second operation can be performed without performing another operation in the retracting operation of the inner needle. It is possible to smoothly transition to the state.

  Still further, the other of the inner and outer catheters and the inner needle or the inner needle hub that fixes and holds the inner needle have an engagement mechanism that continues the first state against the restoring force. It is good to be.

  With this engagement mechanism, the catheter assembly can stably maintain the first state, and the inner catheter can favorably support the inside of the outer catheter.

  Here, the catheter hub may include an inner catheter hub to which the inner catheter is fixed, and an outer catheter hub to which the outer catheter is fixed and movable with respect to the inner catheter hub.

  Since the catheter hub includes the inner catheter hub and the outer catheter hub, the inner and outer catheters can be easily operated.

  The inner needle hub for fixing and holding the inner needle has a retraction locking portion for locking the inner catheter hub when retreating relative to the catheter hub, and the inner catheter hub and the outer The catheter hub may have a release mechanism that releases the locking of the locking portion when retracted when the inner needle is retracted relative to the catheter.

  As described above, the catheter assembly has the retracting locking portion and the release mechanism, so that the inner catheter hub can be retracted based on the retract of the inner needle hub, and the retract of the inner catheter hub can be stopped by the release mechanism. . Thereby, the inner catheter can be disposed at a position retracted to some extent, and the compression of the outer catheter by the living tissue can be supported by the inner catheter.

  Furthermore, the release mechanism may be constituted by a convex portion provided on one of the inner catheter hub and the outer catheter hub and a concave portion provided on the other.

  Thereby, a release mechanism can be made into a simple structure and the manufacturing cost of an inner catheter hub and an outer catheter hub can be reduced.

  Furthermore, it is preferable that the inner needle hub has an advancing locking portion that locks the inner catheter hub and pushes out the inner catheter hub when the inner needle hub moves relative to the catheter hub.

  The catheter assembly can smoothly push out the inner catheter and the inner catheter hub with respect to the outer catheter and the outer catheter hub, and can be easily assembled with each other.

  The inner catheter and the outer catheter are preferably made of materials having different hardnesses.

  As described above, the inner catheter and the outer catheter are made of different materials, so that the outer catheter can obtain a desired flexibility, and a catheter combining the inner catheter and the outer catheter has a desired rigidity. It can be.

  In particular, the outer catheter is preferably more flexible than the inner catheter.

  Thereby, since a flexible outer catheter is inserted into the blood vessel, inflammation and damage to the blood vessel wall can be further reduced.

  According to the present invention, the catheter assembly has an appropriate rigidity at the time of puncture, and can reduce mechanical stimulation to the blood vessel when the catheter is inserted into the blood vessel.

1A is a partial side cross-sectional view showing the overall configuration of the catheter assembly according to the first embodiment of the present invention in a state before puncturing, and FIG. 1B shows an enlarged view of the distal end of the multi-structure needle of FIG. 1A. It is side surface sectional drawing. FIG. 2 is a partial side cross-sectional view showing a post-puncture state in which the inner needle has retracted in the catheter assembly of FIG. FIG. 3A is an explanatory view showing a state at the time of puncture of the multi-structure needle, and FIG. 3B is an explanatory view showing a state at the time of catheter insertion of the multi-structure needle. FIG. 4A is a partial side cross-sectional view showing an overall configuration of the catheter assembly according to the second embodiment in a state before puncturing, and FIG. 4B is a side cross-sectional view showing an enlarged view of the distal end of the multi-structure needle of FIG. It is. It is a partial side sectional view showing the inner needle hub in the state before puncture of the catheter assembly concerning a 3rd embodiment.

  Hereinafter, preferred embodiments of the catheter assembly according to the present invention will be described in detail with reference to the accompanying drawings.

[First Embodiment]
The catheter assembly 10 according to the first embodiment is used when transfusion, blood transfusion, and the like is performed on a patient (living body), and a medical device that punctures, inserts, and indwells a catheter in a patient's body to construct a medical solution introduction unit. Equipment. This catheter assembly 10 is applied to a peripheral vein and inserts a catheter shorter than the central venous catheter. The catheter assembly 10 may be longer than the peripheral venous catheter, for example, a central venous catheter, a PICC, a midline catheter, or the like. The catheter assembly 10 is not limited to a venous catheter, and may be a catheter into which an arterial catheter such as a peripheral artery catheter is inserted.

  As shown in FIG. 1A, the catheter assembly 10 includes an inner needle 12, an inner needle hub 14 that fixes and holds the inner needle 12, a catheter 16 that is disposed outside the inner needle 12, and a catheter 16 that is fixedly held. And a catheter hub 18. In particular, the catheter 16 according to the present embodiment is configured as a double tube (multiple tube) and includes an inner catheter 20 and an outer catheter 30. The catheter hub 18 is also composed of an inner catheter hub 40 for fixing and holding the inner catheter 20 and an outer catheter hub 50 for fixing and holding the outer catheter 30 (hereinafter, the inner catheter hub 40 is referred to as the inner hub 40 and the outer side). The catheter hub 50 is abbreviated as the outer hub 50).

  The catheter assembly 10 forms a multi-structure needle 11 in which the inner needle 12 and the catheter 16 (inner and outer catheters 20 and 30) are overlapped in order from the inside in a state before use (pre-puncture state). In this pre-puncture state, the multi-structure needle 11 has the needle tip 12a of the inner needle 12 protruding beyond the tips of the inner catheter 20 and the outer catheter 30, and is punctured integrally in the patient's body. Then, while maintaining the puncture state, the catheter 16 is inserted into the blood vessel, and the inner needle 12 is retracted and removed from the catheter 16, whereby the catheter 16 is placed in the blood vessel. As will be described later, the catheter 16 may be configured such that only the outer catheter 30 is indwelled, or may be configured such that the outer and inner catheters 20 are overlapped. Hereinafter, each configuration of the catheter assembly 10 will be described in detail.

  The inner needle 12 is configured as a hollow tubular body having rigidity that can puncture the skin of a living body, and includes a sharp needle tip 12a at the tip thereof. A hollow portion 12b is provided in the inner needle 12 along the axial direction. The inner needle 12 has a structure (such as a hole penetrating the hollow portion 12b and the outer surface or a groove formed on the outer peripheral surface of the inner needle 12) that allows blood flashback to be visually recognized when the multi-structure needle 11 is punctured. It should be provided. The inner needle 12 may have a solid structure without the hollow portion 12b.

  As shown in FIGS. 1A and 1B, the inner needle 12 has a step portion 13 at a position away from the needle tip 12a by a predetermined length in the proximal direction. The step portion 13 is provided on the entire circumference in the circumferential direction of the inner needle 12, and protrudes radially outward (outside in the direction perpendicular to the axis of the inner needle 12) from the distal end region α connected to the needle tip 12a. That is, the inner needle 12 is configured such that the tip end region α is thin with the stepped portion 13 as a base point, and the base end region β is thick. The step portion 13 constitutes one of the engagement mechanisms 60 for hooking the inner catheter 20. Note that the stepped portion 13 may be provided only in a part of the inner needle 12 in the circumferential direction.

  Examples of the constituent material of the inner needle 12 include stainless steel, aluminum or aluminum alloy, metal material such as titanium or titanium alloy, hard resin, ceramics, and the like. The inner needle 12 is firmly fixed to the inner needle hub 14 by appropriate fixing means such as fusion, adhesion, and insert molding.

  The inner needle hub 14 of the catheter assembly 10 is a member that holds the inner needle 12 fixedly and moves integrally with the inner needle 12. The inner needle hub 14 is detachably attached to the proximal end of the catheter hub 18 and constitutes a grip portion that is gripped by the user. The inner needle hub 14 has a substantially rectangular tube shape as a whole, and has an R-shaped corner portion and is designed to have an appropriate size (thickness and length) so that the user can easily grip it. ing.

  In the inner needle hub 14 and the distal end portion, there are provided connecting portions 15 that are inserted into and connected to the catheter hub 18 (inner hub 40). The connecting portion 15 is formed in a shape (for example, a columnar shape) corresponding to the inner peripheral surface of the catheter hub 18, and the outer peripheral surface is fitted to 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 when the multi-structure needle 11 is punctured. In addition, the connection structure of the inner needle hub 14 and the catheter hub 18 is not particularly limited, and various configurations (screwed structure and flange portion) that allow the inner needle hub 14 and the catheter hub 18 to be separated by a simple operation. Engagement structure).

  The inner catheter 20 constituting one of the double cage catheters 16 is a tubular member that is flexible and has a predetermined length, and is disposed outside the inner needle 12 to partially Covering. Inside the inner catheter 20, a lumen 20 a is formed which extends along the axial direction of the inner catheter 20 and through which the inner needle 12 can be inserted and disposed.

  The outer peripheral surface on the distal end side of the inner catheter 20 is tapered toward the distal end direction. The inner peripheral surface on the distal end side of the inner catheter 20 is formed in a predetermined shape that can contact the outer peripheral surface of the inner needle 12. Specifically, the first inner peripheral surface 21 contacting the outer peripheral surface of the distal end region α of the inner needle 12 and a diameter larger than the diameter of the first inner peripheral surface 21 on the proximal end side of the first inner peripheral surface 21. A second inner peripheral surface 22 and a third inner peripheral surface 23 having a diameter larger than the diameter of the second inner peripheral surface 22 on the proximal end side of the second inner peripheral surface 22 are provided.

  Between the first inner peripheral surface 21 and the second inner peripheral surface 22, a step-shaped inner hooking portion 24 orthogonal to the axial direction of the inner catheter 20 is provided. The inner hooking portion 24 constitutes the other of the engaging mechanism 60 that is hooked on the stepped portion 13 of the inner needle 12 in a state before puncturing. That is, the engagement mechanism 60 is configured by the inner hook portion 24 and the step portion 13 of the inner needle 12, thereby restricting the inner catheter 20 from retreating relative to the inner needle 12.

  Further, a taper step 25 is provided between the second inner peripheral surface 22 and the third inner peripheral surface 23 so as to expand radially outward toward the proximal direction. The third inner peripheral surface 23 forms a gap 26 with respect to the outer peripheral surface of the inner needle 12 by the taper step 25. On the proximal end side of the inner catheter 20, the third inner peripheral surface 23 extends to form a spatial margin, and the sliding resistance of the inner needle 12 can be reduced.

  The constituent material of the inner catheter 20 is not particularly limited as long as it has appropriate rigidity (rigidity) and flexibility, and an appropriate resin material may be applied. For example, as a constituent material of the inner catheter 20, polytetrafluoroetherene (PTFE), ethylene-tetrafluoroetherene copolymer (ETFE), fluorine-based resin such as bellfluoroalkoxy fluororesin (PFA), polyethylene, polypropylene And olefinic resins such as polyurethane, polyester, polyamide, polyether nylon resin, a mixture of the olefinic resin and an ethylene-vinyl acetate copolymer, and the like.

  The proximal end portion of the inner catheter 20 is fixed to the distal end portion of the inner hub 40 by an appropriate joining method such as caulking, fusion (thermal fusion, high frequency fusion, etc.), adhesion with an adhesive, or the like. The inner hub 40 is inserted into the outer hub 50 and fixed to the outer hub 50 so as to be removable before being punctured.

  Although the constituent material of the inner hub 40 is not particularly limited, for example, a thermoplastic resin such as polypropylene, polycarbonate, polyamide, polysulfone, polyarylate, methacrylate-butylene-styrene copolymer may be applied.

  The inner hub 40 is a cylindrical body having a diameter larger than that of the inner catheter 20, and includes a distal end taper portion 41 that tapers at a steep angle toward the distal end direction, and a gradual connection toward the distal end direction that is continuous with the distal end taper portion 41. And a proximal end taper portion 42 which is tapered at a certain angle. An inner space 40a is formed inside the inner hub 40 and communicates with the lumen 20a of the inner catheter 20 and through which the inner needle 12 is inserted.

  The connecting portion 15 of the inner needle hub 14 is inserted into the proximal end of the proximal end taper portion 42. The proximal inner peripheral surface of the proximal taper portion 42 is formed in an inner surface shape (for example, a luer taper) into which the connecting portion 15 is fitted. An inner hub side flange portion 43 that protrudes radially outward is provided on the outer peripheral surface of the proximal end of the proximal end taper portion 42.

  Further, the catheter assembly 10 circulates the infusion agent through the internal space 40a when the inner catheter 20 and the inner hub 40 are placed together with the outer catheter 30 and the outer hub 50. For this reason, in the internal space 40a, there are a hemostasis valve (not shown) that prevents backflow of blood when the inner needle 12 is punctured, a plug (not shown) that allows infusion through the hemostasis valve as the connector of the infusion tube is inserted. It may be accommodated.

  A rubber member 44 (elastic portion) that can expand and contract in the axial direction of the inner hub 40 is provided at an intermediate position in the axial direction of the inner hub 40 according to the present embodiment. The rubber member 44 has an outer shape that aligns with the cylindrical portions of the front and rear inner hubs 40 (continuous in series), and circulates in an annular shape along the circumferential direction of the inner hub 40.

  The rubber member 44 is elastically deformed (stretched) in the axial direction of the inner hub 40, whereby the inner hub 40 and the inner catheter 20 on the distal end side with respect to the rubber member 44 and the inner hub 40 on the proximal end side with respect to the rubber member 44. And change the relative distance. Due to the expansion and contraction of the rubber member 44, the distal end of the inner catheter 20 is brought into contact with the distal end of the outer catheter 30 as shown in FIG. 1A (pre-puncture state) and from the pre-puncture state as shown in FIG. It becomes possible to shift to the second state (post-puncture state) retracted in the proximal direction.

  As shown in FIGS. 1A and 1B, the outer catheter 30 of the catheter assembly 10 is a flexible tubular member, like the inner catheter 20, and the entire inner catheter 20 extending from the outer hub 50. Covering. Inside the outer catheter 30, a lumen 30a is formed that extends along the axial direction of the outer catheter 30 and in which the inner needle 12 and the inner catheter 20 can be placed.

  The outer peripheral surface on the distal end side of the outer catheter 30 is tapered toward the distal end direction. The outer catheter 30 extends with a substantially constant thickness along the axial direction, and the inner peripheral surface constituting the lumen 30 a is in contact with the outer peripheral surface of the inner catheter 20.

  The inner peripheral surface on the distal end side of the outer catheter 30 is formed so as to fit (surface contact) with the outer peripheral surface of the tapered inner catheter 20, and the distal end of the outer catheter 30 is more advanced than the inner catheter 20. It is in front and is in contact with the outer peripheral surface of the inner needle 12. With such a shape, the inner side of the outer catheter 30 is favorably supported when the multi-structure needle 11 is punctured and the like, and the bending to the inner side in the radial direction is suppressed. Further, the movement of the outer catheter 30 in the proximal direction relative to the inner catheter 20 is also restricted.

  The outer catheter 30 is formed to be softer (that is, different in hardness) than the inner catheter 20. The softness of the outer catheter 30 may be realized by a material softer than the constituent material of the inner catheter 20, or may be realized by a shape such as making the outer catheter 30 thin. The material which comprises the outer catheter 30 is not specifically limited, For example, it is good to apply resin materials, such as a polyurethane type | system | group (very soft polyurethane etc.), a polyether type | system | group, and a polyolefin type.

  The proximal end portion of the outer catheter 30 is fixed to the distal end portion of the outer hub 50 by an appropriate joining method such as caulking, fusion (thermal fusion, high frequency fusion, etc.), adhesion with an adhesive, or the like. For example, the outer peripheral surface on the proximal end side of the outer catheter 30 extends radially outward in the outer hub 50, and the outer peripheral surface is closely fixed to the inner peripheral surface of the outer hub 50 in a planar shape.

  The outer hub 50 has an accommodating space 50 a that communicates with the inner lumen 30 a of the outer catheter 30, and is formed in a cylindrical shape that is slightly thicker than the inner hub 40. The outer hub 50 includes a head 51 to which the outer catheter 30 is fixed, a tapered connecting portion 52 that is continuous with the proximal end of the head 51 and tapers at a steep angle toward the distal end, and a proximal end of the tapered connecting portion 52. And a body portion 53 that tapers at a gentle angle toward the distal direction.

  The tapered connecting portion 52 of the outer hub 50 is set at the same inclination angle as the tip tapered portion 41 of the inner hub 40, and the outer peripheral surface of the tip tapered portion 41 can come into surface contact. When the tip tapered portion 41 and the taper connecting portion 52 come into contact with each other before puncturing, the inner hub 40 is prevented from moving to the tip more than necessary than the outer hub 50.

  On the other hand, the trunk portion 53 is set at the same inclination angle as the proximal end taper portion 42 of the inner hub 40, and the outer peripheral surface of the proximal end taper portion 42 can be in surface contact. The trunk portion 53 is continuous in series with the same material. Further, an outer hub side flange portion 54 protruding outward in the radial direction is formed on the outer peripheral surface on the proximal end side of the trunk portion 53.

  The inner hub 40 and the outer hub 50 constitute one catheter hub 18 by being detachably fixed to each other in a state before puncturing. For example, the outer diameter of the proximal taper portion 42 on the proximal end side of the rubber member 44 of the inner hub 40 is slightly larger than the inner diameter of the proximal end side (body portion 53) of the outer hub 50. When the inner hub 40 is inserted deeply into the outer hub 50, the inner hub 40 is engaged with an appropriate frictional force. The fixing means for the inner hub 40 and the outer hub 50 is not particularly limited. For example, the base end taper portion 42 and the body 53 are screwed together, and the inner hub side flange portion 43 and the outer hub side flange portion 54 are connected. It is advisable to adopt a structure that fits together.

  The catheter assembly 10 having the above configuration constitutes the multi-structure needle 11 in which the needle tip 12a of the inner needle 12 is exposed from the distal end of the catheter 16 (outer catheter 30) as described above in the state before puncturing. In this state, the axial centers of the inner needle 12 and the inner and outer catheters 20 and 30 are coaxially arranged.

  In the distal end portion of the multi-structure needle 11, the first inner peripheral surface 21 of the inner catheter 20 is in surface contact with the distal end region α of the inner needle 12, and the second inner peripheral surface 22 of the inner catheter 20 is the base of the inner needle 12. It is in surface contact with the end region β. On the other hand, the third inner peripheral surface 23 of the inner catheter 20 faces the proximal end region β of the inner needle 12 with a gap 26 therebetween. Furthermore, the inner peripheral surface of the outer catheter 30 is in contact with the outer peripheral surface of the inner catheter 20 without a gap and covers the inner catheter 20.

  On the other hand, the catheter hub 18 is fixed by inserting the inner hub 40 into the outer hub 50, and the connecting portion 15 of the inner needle hub 14 is inserted and mounted from the proximal end of the catheter hub 18. Further, in the state where the inner hooking portion 24 of the inner catheter 20 is engaged with the step portion 13 of the inner needle 12 as described above, the distal end position of the inner catheter 20 is defined by the inner needle 12, and the inner catheter 20 is connected to the inner hub 40. It works to pull out the tip in the direction of the tip.

  Here, since the inner hub 40 has the rubber member 44 described above, the rubber member 44 is extended by the pulling force of the inner catheter 20 to be elongated in the axial direction. Note that the tip taper portion 41 of the inner hub 40 is in contact with the taper coupling portion 52 of the outer hub 50, so that the rubber member 44 is prevented from extending more than necessary. That is, in the state before puncturing, the elastic restoring force of the rubber member 44 is applied to the inner catheter 20 in the proximal direction relative to the outer catheter 30. This elastic restoring force is smaller than the engaging force between the stepped portion 13 of the inner needle 12 and the inner hooking portion 24 of the inner catheter 20, and from the fitting force of the proximal end portion of the inner hub 40 and the connecting portion 15 of the inner needle hub 14. Is also small. Therefore, the catheter assembly 10 can stably maintain the state shown in FIG. 1A.

  The catheter assembly 10 according to the first embodiment is basically configured as described above, and the effects thereof will be described below.

  When transfusion or blood transfusion is performed on a patient, a user (physician or nurse or the like) grasps the inner needle hub 14 and puts the multi-structure needle 11 in a pre-puncture state into the patient's blood vessel 100 as shown in FIG. 3A. Puncture inside. At the time of puncturing, the inner catheter 20 is in contact with and supported by the inner needle 12 near the proximal end of the needle tip 12a, and the outer catheter 30 is further in contact and supported by the inner needle 12 and the inner catheter 20. As a result, the outer catheter 30 that is configured flexibly is inserted into the blood vessel 100 without causing bending or wrinkles even when receiving resistance from living tissue such as skin or blood vessels.

  In puncture, when the needle tip 12a of the inner needle 12 enters the blood vessel 100 beyond the blood vessel wall 101, the user stops the insertion of the inner needle 12 and maintains this position relative to the inner needle 12. An operation to advance the catheter 16 is performed. At this time, the inner needle hub 14 fixed to the catheter hub 18 (inner hub 40) is retracted in the proximal direction, and the inner needle hub 14 is detached from the inner hub 40. The inner needle 12 is also retracted integrally with the inner needle hub 14.

  The catheter assembly 10 also retracts the inner catheter 20 based on the retraction of the inner needle 12. That is, the inner catheter 20 and the inner hub 40 are disposed at positions before engaging the engaging mechanism 60 of the inner needle 12 and in contact with the distal end of the outer catheter 30 as described above before puncturing. In this state, since the rubber member 44 is extended to apply an elastic restoring force in the proximal direction to the inner catheter 20, when the step portion 13 (engagement mechanism 60) of the inner needle 12 is retracted, the inner catheter 20 is also moved. At the same time, it will retreat.

  The retraction of the inner catheter 20 is continued until the elastic deformation of the rubber member 44 ends (becomes a natural state) as shown in FIG. After the rubber member 44 is elastically restored, the inner catheter 20 stops moving backward, and the inner needle 12 and the inner needle hub 14 move backward relative to the inner catheter 20 and the inner hub 40 and are removed from the inner hub 40. That is, the catheter assembly 10 shifts to a post-puncture state in which the distal end of the inner catheter 20 is disposed at a position separated from the distal end of the outer catheter 30 by the amount of expansion / contraction of the rubber member 44.

  In this post-puncture state, as shown in FIG. 3B, the inner catheter 20 is not completely removed from the body of the patient, and the inner catheter 20 can guide the insertion of the outer catheter 30. Further, the catheter assembly 10 can make a distance that allows the outer catheter 30 to be sufficiently bent between the insertion site and the blood vessel wall 101 on the opposite side by the retraction of the inner catheter 20. Thereby, the user can easily insert the outer catheter 30 in the extending direction of the blood vessel 100.

  Further, as described above, since the outer catheter 30 is configured flexibly, the distal end of the outer catheter 30 strongly contacts (rubs) with the blood vessel wall 101 to cause inflammation or damage to the blood vessel wall 101. Can be suppressed.

  After the outer catheter 30 is inserted into the blood vessel 100, the outer catheter 30 and the outer hub 50 are placed in the patient. At this time, at least the inner needle 12 is also detached from the inner catheter 20. When the outer catheter 30 is indwelled, an infusion tube connector (not shown) is attached to the proximal end side of the outer hub 50. As a result, the infusion agent is supplied from the infusion tube via the outer hub 50 and the outer catheter 30.

  In the placement, the inner catheter 20 and the inner hub 40 may be placed together, or the inner catheter 20 and the inner hub 40 may be pulled out (detached) from the outer catheter 30 and the outer hub 50 and placed. . When the inner catheter 20 is placed together with the outer catheter 30, kinking or the like of the outer catheter 30 is suppressed, and even when the inner catheter 20 receives pressure from a living tissue, the inner catheter 20 can satisfactorily prevent the outer catheter 30 from being crushed. . When only the outer catheter 30 is indwelled, it is possible to suppress inconveniences such as the outer catheter 30 applying a strong stress to the insertion site and spreading the wound.

  As described above, in the catheter assembly 10 according to the first embodiment, the inner catheter 20 supports the outer catheter 30 from the inner side in a state before puncturing, and appropriate rigidity can be obtained as the entire catheter 16. For this reason, even if the outer catheter 30 receives the resistance force of the living tissue at the time of puncturing, the bending can be suppressed, and the catheter 16 can be smoothly inserted into the blood vessel 100. In addition, since the inner catheter 20 and the outer catheter 30 are relatively movable in the longitudinal direction, the influence of the inner catheter 20 can be suppressed before the outer catheter 30 is inserted into the blood vessel 100. Therefore, the catheter assembly 10 can reduce the mechanical irritation | stimulation to the blood vessel 100, and can indwell the catheter 16 better.

  In this case, the inner catheter 20 can be moved relative to the outer catheter 30 based on the retraction of the inner needle 12, so that the outer catheter 30 can be favorably supported by the inner catheter 20 until the inner needle 12 is retracted. Further, the catheter assembly 10 can easily switch between support and release of the distal end of the outer catheter 30 by the distal end of the inner catheter 20 by the transition between the pre-puncture state and the post-puncture state.

  The inner catheter 20 is fixed via the rubber member 44, whereby the elastic force of the rubber member 44 is applied, and relative movement with respect to the outer catheter 30 can be easily performed. Since the rubber member 44 has a restoring force in a direction in which the distal end of the outer catheter 30 and the distal end of the inner catheter 20 are separated from each other before puncturing, the rubber member 44 is brought into the post-puncture state by retreating the inner needle 12 without performing another operation. Smooth transition can be achieved. Furthermore, the catheter assembly 10 has the engagement mechanism 60, so that the state before puncturing can be stably maintained, and the outer catheter 30 can be favorably supported by the inner catheter 20.

  Furthermore, since the inner catheter 20 and the outer catheter 30 are made of different materials, the outer catheter 30 can obtain a desired flexibility. When the flexible outer catheter 30 is inserted into the blood vessel 100, inflammation and damage of the blood vessel wall 101 can be further reduced. In addition, the catheter 16 in which the inner catheter 20 and the outer catheter 30 are combined can also have a desired rigidity, and can be satisfactorily inserted into the living body.

  The catheter assembly 10 according to the present invention is not limited to the above-described embodiment, and various modifications can be made along the gist of the invention. For example, in the catheter assembly 10 according to the first embodiment, the rubber member 44 is applied as an elastic portion that applies a backward force to the inner catheter 20, but the configuration is not limited thereto. As another elastic portion, for example, a spring member can be applied.

  Further, for example, the inner catheter 20 and the outer catheter 30 may be configured such that the distal end of the inner catheter 20 protrudes from the distal end of the outer catheter 30 in a state before puncturing. For example, the multi-structure needle 11 in the pre-puncture state forms a tapered shape in which the distal end surface of the inner catheter 20 and the distal end surface of the outer catheter 30 are continuous from the outer peripheral surface of the inner needle 12 toward the radially outer side and the proximal end direction. Then, the patient can be punctured well.

[Second Embodiment]
As shown in FIG. 4A, the catheter assembly 10A according to the second embodiment includes an engagement mechanism 61 in which the inner needle 12 and the inner needle hub 14, and the inner catheter 20 and the inner hub 40 are engaged. This is different from the engagement mechanism 60 according to FIG. In the following description, the same reference numerals are given to the same configuration or the same function as the catheter assembly 10 according to the first embodiment, and the detailed description is omitted.

  Specifically, the engagement mechanism 61 includes a protruding portion 15a that protrudes in the distal direction from the distal end surface of the inner needle hub 14 (connecting portion 15), and an inner hub 40 (tip tapered portion 41). That is, with the connecting portion 15 of the inner needle hub 14 inserted and fitted into the inner hub 40, the tip portion of the protruding portion 15a contacts and supports the inner peripheral surface of the tip tapered portion 41, whereby the rubber member 44 is obtained. The stretched state of the (elastic part) is maintained. In the example of illustration, although the protrusion part 15a is formed in the cylinder shape, not only this but what was formed in the rod shape may protrude and comprise 1 or more. In the illustrated example, the protruding portion 15 a is integrally formed with the connecting portion 15. However, the protruding portion 15 a is not limited to this, and may be configured by joining a separately formed member to the connecting portion 15.

  Therefore, as shown in FIG. 4B, the inner needle 12 of the catheter assembly 10A (multiple structure needle 11A) employs a configuration in which the step portion 13 is not provided on the proximal end side of the needle tip 12a, that is, the axial direction of the inner needle 12 It can be set as the shape which extended the outer diameter uniformly along. Thereby, manufacture of the inner needle 12 becomes simpler. Further, the inner catheter 20 can also be configured not to include the inner hooking portion 24 on the inner peripheral surface, and the manufacture becomes simpler.

  In short, the engagement mechanisms 60 and 61 that maintain the position of the inner catheter 20 in the pre-puncture state (position where the distal end of the outer catheter 30 and the distal end of the inner catheter 20 are in contact) may adopt various configurations. For example, as shown by a two-dot chain line in FIG. 4A, the engaging mechanism 62 projects the projecting portion 15b radially outward from the outer peripheral surface of the inner needle 12, and the inner periphery of the inner hub 40 (tip tapered portion 41). The structure engaged with a surface may be sufficient.

[Third Embodiment]
As shown in FIG. 5, the catheter assembly 10B according to the third embodiment is configured such that the inner needle hub 14, the inner hub 40, and the outer hub 50 are interlocked with each other to retract the inner catheter 20 and the inner hub 40. Different from the catheter assemblies 10 and 10A according to the first and second embodiments. That is, the catheter assembly 10B can be configured such that the inner hub 40 does not include an elastic portion. Note that the distal end side of the catheter assembly 10B can adopt the same configuration as the multiple structure needle 11A of the second embodiment (see FIG. 4B).

  Specifically, in the inner needle hub 70, the connecting portion 71 inserted into the catheter 16 extends long along the axial direction. A first engaging convex portion 72 and a second engaging convex portion 73 that engage with the inner hub 40 are provided at the distal end portion of the connecting portion 71. The first engaging convex portion 72 is provided on the distal end side in the axial direction of the connecting portion 71 and circulates around the outer peripheral surface of the columnar connecting portion 71 in the circumferential direction. The second engaging convex portion 73 is provided at a position that is shortly spaced from the first engaging convex portion 72 in the proximal direction. The second engaging convex portion 73 protrudes larger in the radial direction than the first engaging convex portion 72.

  On the other hand, the inner hub 40 has a proximal tapered portion 42 that is short in the axial direction, and the inner hook convex portion 46 that protrudes radially inward at the most proximal end and the inner hook convex portion 46 at the same position in the axial direction. And an outer catching protrusion 47 protruding outward in the direction. The inner hook convex portion 46 and the outer hook convex portion 47 circulate around the inner peripheral surface and the outer peripheral surface of the inner hub 40 in an annular manner, and protrude with the same amount of protrusion in opposite directions.

  The inner hook convex portion 46 is engaged with the first and second engaging convex portions 72 and 73 of the inner needle hub 14, and the catheter assembly 10 includes the first engaging convex portion 72 and the inner hook convex portion. An engaging mechanism 63 is constituted by the convex portion 46. On the other hand, the outer catching protrusion 47 is configured to be caught on the inner peripheral surface of the outer hub 50.

  The outer hub 50 has a first engagement concave portion 56 and a second engagement concave portion 57 on the inner peripheral surface of the body portion 53, and the outer hooking convex portion is between the first and second engagement concave portions 56, 57. A shallowly recessed passage 58 is provided so that 47 can slide. The outer hooking convex portion 47 of the inner hub 40 is inserted and engaged with the first and second engaging concave portions 56 and 57. The first engaging recess 56 is recessed shallowly from the inner peripheral surface. The second engagement recess 57 is provided at a position away from the first engagement recess 56 in the proximal direction to some extent, and is deeper than the first engagement recess 56. In particular, the outer hub 50 has a proximal end side (inner peripheral surface of the body portion 53) of the second engagement recess 57 protruding radially inward from a distal end side (passage 58) of the second engagement recess 57. Thus, it is possible to reliably lock the outer catching convex portion 47.

  The catheter assembly 10B according to the third embodiment is basically configured as described above. In the assembly, the catheter assembly 10B is in a state where the inner needle 12 is inserted into the inner catheter 20, and the inner needle hub 14 is inserted into the accommodating space 50a of the outer hub 50 together with the inner hub 40. At this time, the inner hooking convex portion 46 of the inner hub 40 is disposed between the first engaging convex portion 72 and the second engaging convex portion 73 of the inner needle hub 14. When the inner needle hub 14 is inserted, the second engagement convex portion 73 pushes out the inner hooking convex portion 46 as the inner needle hub 14 advances in the distal direction. Thereby, the inner hub 40 is advanced relative to the outer hub 50. That is, the 2nd engagement convex part 73 functions as a locking part at the time of advance.

  The advancement of the inner hub 40 is continued until the outer catching projection 47 of the inner hub 40 is engaged with the first engagement recess 56 of the outer hub 50. In this engaged state, the distal end taper portion 41 of the inner hub 40 is in contact with the taper coupling portion 52 of the outer hub 50, and the catheter hub 18 is configured in which the inner hub 40 and the outer hub 50 are in contact with each other. The multi-structure needle 11 also constructs a pre-puncture state in which the distal end of the inner catheter 20 is in contact with the distal end of the outer catheter 30.

  When the catheter assembly 10b is used, the user punctures the patient with the multi-structure needle 11 and retracts the inner needle hub 14 relative to the catheter hub 18 in the punctured state, thereby causing the inner needle 12 to move relative to the outer catheter 30. Retreat. At this time, the first engaging convex portion 72 of the inner needle hub 14 hooks the inner hooking convex portion 46 of the inner hub 40 to retract the inner hub 40 integrally. The engaging force between the first engaging convex portion 72 and the inner hooking convex portion 46 is designed to be stronger than the engaging force between the outer hooking convex portion 47 and the first engaging concave portion 56. The hub 40 can be reliably retracted.

  Retraction of the inner needle hub 14 and the inner hub 40 is continued until the outer hooking projection 47 is engaged with the second engagement recess 57 of the outer hub 50. Here, the engaging force between the outer hooking convex portion 47 and the second engaging concave portion 57 is designed to be stronger than the engaging force between the first engaging convex portion 72 and the inner hooking convex portion 46. Therefore, after the outer hooking convex portion 47 is engaged with the second engaging concave portion 57, when the inner needle hub 14 is further retracted, the engagement between the first engaging convex portion 72 and the inner hooking convex portion 46 is released. Is done. That is, the outer catching protrusion 47 and the second engagement recess 57 function as a release mechanism 65 having a release mechanism for releasing the locking by the first engagement protrusion 72.

  By this release mechanism 65, the inner needle hub 14 moves backward leaving the inner hub 40. As a result, the catheter assembly 10B moves the inner needle 12 and the inner needle hub 14 from the inner and outer catheters 20 and 30 while maintaining the post-puncture state in which the distal end of the inner catheter 20 is separated from the distal end of the outer catheter 30 by a predetermined distance. Can be withdrawn.

  As described above, the catheter assembly 10B according to the third embodiment is configured to release the engaging mechanism 63, the outer hooking convex portion 47, and the second engaging concave portion 57 by the first engaging convex portion 72 and the inner hooking convex portion 46. A mechanism 65 is included. Accordingly, the inner hub 40 can be retracted based on the retreat of the inner needle hub 14, and the retreat of the inner hub 40 can be stopped by the release mechanism 65. Thereby, the inner catheter 20 can be disposed at a position retracted to some extent, and the compression of the outer catheter 30 by the living tissue can be supported by the inner catheter 20.

  Further, the release mechanism 65 can be easily configured by the outer hooking convex portion 47 of the inner hub 40 and the second engaging concave portion 57 of the outer hub 50, thereby reducing the manufacturing cost of the inner hub 40 and the outer hub 50. can do. Further, the catheter assembly 10B can smoothly push out the inner catheter 20 and the inner hub 40 with respect to the outer catheter 30 and the outer hub 50 by the second engaging convex portion 73 of the inner needle hub 14, and can be assembled to each other. Can be easily performed.

  In addition, the catheter assembly 10B according to the third embodiment can take various application examples and modifications. For example, the convex portions or the concave portions provided on the inner needle hub 14, the inner hub 40, and the outer hub 50 only need to obtain a desired engagement force, and may be freely designed with respect to the arrangement target.

  Further, when the inner hub 40 is removed together with the removal of the inner needle hub 14 from the outer hub 50, the outer hub 50 may not include the second engagement recess 57.

  Further, the first and second engaging convex portions 72 and 73, the inner and outer hooking convex portions 46 and 47, and the first and second engaging concave portions 56 and 57 are partially or entirely formed as non-annular protrusions. May be. For example, when all the protrusions and recesses are formed on the protrusions, a mechanism (for example, spline engagement) for positioning the circumferential positions of the inner needle hub 14, the inner hub 40, and the outer hub 50 may be employed.

DESCRIPTION OF SYMBOLS 10, 10A, 10B ... Catheter assembly 11 ... Multi-structure needle 12 ... Inner needle 13 ... Step part 14, 70 ... Inner needle hub 15, 71 ... Connection part 15a, 15b ... Protrusion part 16 ... Catheter 18 ... Catheter hub 20 ... Inner catheter 24 ... inner hook part 30 ... outer catheter 40 ... inner catheter hub 44 ... rubber member 46 ... inner hook convex part 47 ... outer hook convex part 50 ... outer catheter hub 52 ... taper coupling part 56 ... first engagement concave part 57 ... 2nd engagement recessed part 60-63 ... Engagement mechanism 65 ... Release mechanism 72 ... 1st engagement convex part 73 ... 2nd engagement convex part

Claims (12)

An inner needle,
An inner catheter disposed outside the inner needle;
An outer catheter disposed outside the inner catheter;
A catheter hub for securing and holding the inner and outer catheters,
The inner needle is retractable relative to the outer catheter and is removable from the inner and outer catheters;
The catheter assembly, wherein the inner catheter and the outer catheter are movable relative to each other in the longitudinal direction of the inner needle. The catheter assembly of claim 1.
The catheter assembly is characterized in that the inner catheter is movable relative to the outer catheter based on the retraction of the inner needle. The catheter assembly according to claim 1 or 2,
The catheter assembly is
A first state in which the tip of the inner catheter contacts the tip of the outer catheter;
A catheter assembly, wherein the distal end of the inner catheter can be shifted to a second state in which the distal end of the inner catheter is separated from the distal end of the outer catheter. The catheter assembly of claim 3,
One of the inner and outer catheters is fixed in a relatively immovable manner relative to the catheter hub,
The catheter assembly, wherein the other of the inner and outer catheters is fixed to the catheter hub via an elastic portion. The catheter assembly according to claim 4.
The elastic part has a restoring force in a direction in which the distal end of the inner catheter and the distal end of the outer catheter are separated from each other in the first state. The catheter assembly according to claim 5.
The other of the inner and outer catheters and the inner needle or the inner needle hub that holds and holds the inner needle have an engagement mechanism that continues the first state against the restoring force. A catheter assembly. The catheter assembly according to any one of claims 1 to 6,
The catheter hub is
An inner catheter hub to which the inner catheter is fixed;
A catheter assembly comprising: an outer catheter hub to which the outer catheter is fixed and movable with respect to the inner catheter hub. The catheter assembly of claim 7,
The inner needle hub that fixes and holds the inner needle has a retraction locking portion that locks the inner catheter hub when retreating relative to the catheter hub,
The catheter assembly, wherein the inner catheter hub and the outer catheter hub have a release mechanism that releases the locking of the locking portion when retracted when the inner needle is retracted relative to the catheter. The catheter assembly according to claim 8.
The release mechanism includes a convex portion provided on one of the inner catheter hub and the outer catheter hub and a concave portion provided on the other. The catheter assembly according to claim 8 or 9,
The catheter assembly, wherein the inner needle hub has an advancing locking portion that locks the inner catheter hub and pushes out the inner catheter hub when the inner needle hub moves relative to the catheter hub. The catheter assembly according to any one of claims 1 to 10,
The catheter assembly, wherein the inner catheter and the outer catheter are made of materials having different hardnesses. The catheter assembly of claim 11, wherein
The catheter assembly, wherein the outer catheter is more flexible than the inner catheter.

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