Mini midline conduit

Abstract

The invention discloses a mini midline catheter, and relates to the technical field of medical instruments, the mini midline catheter comprises a catheter sheath, an expansion sheath and a protective sleeve, the catheter sheath comprises a catheter joint, a protective sleeve and an implantation catheter, the expansion sheath comprises an expansion joint, a locking ring and an expansion catheter, the catheter sheath wraps the expansion sheath, and the protective sleeve is connected with the expansion joint. The implantation catheter is wrapped outside the expansion catheter, the length of the expansion catheter is larger than that of the implantation catheter, the catheter connector is connected with the locking ring Luer, and the implantation catheter is made of a material with the biological risk assessment end point reaching the long-term or lasting contact level of circulating blood externally connected into a medical device. The dilation catheter and the dilation joint are connected through an injection molding and rubber coating process, and the implantation catheter and the catheter joint are connected through an injection molding and rubber coating process. The mini midline catheter is convenient, accurate and safe to operate, and the infusion time is prolonged compared with an indwelling needle scheme.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a mini midline catheter. Background Art

[0002] Intravenous infusion is one of the most commonly used treatment methods in clinical practice. It injects drugs into the human body through peripheral blood vessels to achieve the purpose of treatment. The existing short-term and medium-term implantable infusion methods include indwelling needles, peripherally inserted central venous catheters, central venous catheters, and implantable drug delivery devices. Compared with the time of implantation, the infusion time of indwelling needles does not exceed 7 days, and the longest indwelling time of peripherally inserted central venous catheters, central venous catheters, and implantable drug delivery device needles is no more than 1 year. From the operation comparison, the indwelling needle is easy to operate, with low risk, and can be operated in a general ward; the peripherally inserted central venous catheter, central venous catheter, and implantable drug delivery device needle need to be operated in a dedicated operating room, which is complicated and risky. Among the above products, there is a lack of an infusion method with a longest infusion time longer than that of an indwelling needle, but shorter than that of a peripherally inserted central venous catheter, a central venous catheter, and an implantable drug delivery device, so as to meet the demand for an infusion time of about 1 month. At the same time, it has the characteristics of easy operation, accuracy, and safety. Summary of the invention

[0003] Technical problem to be solved by the invention

[0004] The technical problem to be solved by the present invention is to provide a mini midline catheter which is easy to operate, accurate and safe, and prolongs the infusion time compared with the indwelling needle solution.

[0005] Technical Solution

[0006] To solve the above problems, the technical solution provided by the present invention is:

[0007] A mini midline catheter comprises a catheter sheath, an expansion sheath and a sheath tube, wherein the catheter sheath comprises a catheter joint, a protective sleeve and an implanted catheter, the expansion sheath comprises an expansion joint, a locking ring and an implanted catheter, the catheter sheath is wrapped around the outside of the expansion sheath, the implanted catheter is wrapped around the outside of the expansion catheter, the length of the implanted catheter is longer than that of the implanted catheter, the catheter joint is Luer-connected to the locking ring, the implanted catheter is made of a material having a biological risk assessment endpoint reaching a level above the long-term or persistent contact level with circulating blood of an externally connected medical device, the implanted catheter and the expansion joint are connected by an injection molding and rubber-coating process, and the implanted catheter and the catheter joint are connected by an injection molding and rubber-coating process.

[0008] Improved operating convenience and accuracy

[0009] Luer connection and injection molding and overmolding process: The catheter connector and the expansion sheath locking ring adopt standardized Luer connection to ensure reliable sealing and quick docking. Combined with the injection molding and overmolding one-piece molding process (expansion catheter-expansion connector, implant catheter-catheter connector), it eliminates the leakage risk of traditional gluing or welding, simplifies the operation steps, and reduces assembly errors.

[0010] Advantage of dilatation catheter length: The dilatation catheter is longer than the implantation catheter, and a stable channel can be established first during puncture, providing precise guidance for subsequent implantation of the catheter and reducing vascular damage caused by repeated adjustments.

[0011] Safety enhancement and complication control

[0012] Biocompatible material guarantee: The implanted catheter is made of materials that meet the standards for long-term or persistent contact with circulating blood, which significantly reduces the risks of thrombosis, inflammatory response and biological toxicity, and meets the needs of long-term retention.

[0013] Double-layer protection mechanism of the catheter sheath: the layered structure of the catheter sheath wrapping the dilation sheath and the implanted catheter wrapping the dilation catheter not only avoids the invasion of external contamination, but also reduces the risk of catheter breakage or displacement through the protective cover. The double protection enhances the infection prevention and control capabilities.

[0014] Prolonged retention time and optimized function

[0015] Enhanced structural stability: The injection molding and rubber coating process allows the catheter and the connector to be seamlessly combined, with high mechanical strength, excellent resistance to pulling and fatigue, and can adapt to external force interference during patients' daily activities and reduce accidental tube removal.

[0016] Optimized blood flow compatibility: high-grade biomaterials have a smooth surface and are resistant to protein adsorption. Combined with a reasonable tube diameter design, they maintain patency and avoid premature tube removal due to thrombosis or fibrous sheath formation. Compared with traditional indwelling needles (usually replaced within 72 hours), they significantly extend the infusion cycle to 30 days.

[0017] Optionally, the implant catheter is made of TPU material.

[0018] Meets Class B biocompatibility standards:

[0019] After strict purification and formula optimization, the TPU material meets the Class B requirements (long-term or persistent contact) of "external access devices contacting circulating blood" in the GB / T 16886.1-2022 / ISO10993-1:2018 standard. It has low cytotoxicity, non-sensitizing and excellent blood compatibility, significantly reducing the risk of thrombosis and inflammatory response.

[0020] Surface inertness and resistance to protein adsorption:

[0021] TPU has a dense molecular chain structure, a smooth surface and stable chemical properties, which can reduce platelet adhesion and fibrinogen deposition, avoid lumen blockage or thrombosis, and prolong the patency of the catheter in the blood vessel.

[0022] No plasticizer precipitation:

[0023] Compared with traditional materials such as PVC, TPU does not require the addition of phthalate plasticizers, avoiding the release of harmful substances under long-term retention and ensuring patient safety.

[0024] Balance of flexibility and folding resistance:

[0025] TPU has both high elasticity (similar to rubber) and moderate rigidity. The implanted catheter can bend with the blood flow in the blood vessel without collapsing. At the same time, it can resist deformation due to external forces, reducing the risk of damage to the blood vessel wall.

[0026] Fatigue resistance and durability:

[0027] TPU has excellent resistance to repeated bending (can withstand millions of bending cycles), which can adapt to patients' limb movements or changes in body position and reduce catheter rupture or leakage caused by material fatigue.

[0028] Compatible with injection molding process:

[0029] TPU and the catheter connector are bonded at the molecular level through the injection molding process, with strong interface sealing, avoiding the aging and shedding problems of traditional adhesives and improving the overall structural reliability.

[0030] Long-term retention stability:

[0031] TPU has better hydrolysis resistance than ordinary polyurethane and is not easily degraded under long-term immersion in blood. Combined with anti-calcification modification (such as adding hydrophilic coating), it can maintain the mechanical properties of the catheter and support a safe retention period of 30 days.

[0032] Improved operating feel:

[0033] The TPU catheter is moderately soft and can easily pass through the curved parts of blood vessels during puncture, reducing mechanical stimulation to the vascular endothelium and lowering the difficulty of catheterization. It is especially suitable for patients with thin blood vessels or those with poor elasticity.

[0034] Image compatibility:

[0035] TPU can be modified by adding contrast agents such as barium sulfate to allow the catheter to be clearly visualized under X-rays, facilitating intraoperative positioning and postoperative monitoring, and reducing the risk of misplacement or displacement.

[0036] Processing convenience:

[0037] TPU can be formed through conventional processes such as extrusion and injection molding, and its layered co-extrusion technology with expansion catheters (such as PEBAX materials) is mature, which is conducive to the precise control of catheter wall thickness and flexibility.

[0038] Recyclability:

[0039] Theoretically, TPU materials can be recycled and reused (medical-grade purification treatment is required), which is in line with the development trend of green medicine and reduces the environmental burden of long-term use.

[0040] Optionally, the catheter connector is connected to the locking ring via a Luer lock.

[0041] The Luer lock adds a thread structure on the basis of the cone, which needs to be rotated to lock, making the connection more secure. It has strong anti-falling properties and is suitable for high-pressure or mobile scenarios.

[0042] Optionally, the inner wall of the locking ring is provided with a thread groove, and the outer side of the catheter connector is provided with a thread matching the thread groove.

[0043] The screw-on design of the thread groove and the thread is in accordance with the Luer Lock standard. Compared with the traditional Luer Slip, the mechanical interlocking structure is formed by rotational locking, which can resist accidental tube removal caused by external force or patient activity, and is especially suitable for scenarios with fluctuating infusion pressure or frequent limb movement. Anti-torsion and anti-pulling: The threaded meshing surface is evenly stressed, dispersing external stress, avoiding joint breakage or seal failure caused by single-point stress concentration, and significantly improving the stability of the catheter system in complex mechanical environments.

[0044] Optionally, the locking ring is sleeved outside the expansion joint, and an expansion ring protrusion is provided on the circumference of the expansion joint to elastically engage with the inner wall of the locking ring.

[0045] The expansion ring convexity on the side of the expansion joint forms an elastic interference fit with the inner wall of the locking ring, and uses the elastic deformation of the material to achieve "press and lock", replacing traditional threaded screwing or adhesive fixation, reducing the connection steps (no rotation is required), and is especially suitable for one-handed operation or emergency catheterization scenarios.

[0046] Optionally, the expansion joint is provided with a rotating ring convexity, and friction ribs are provided outside the rotating ring convexity.

[0047] The rotating ring convex helps the expansion joint to rotate, and the expansion Luer interface of the expansion sheath is a Luer lock structure, which is convenient for controlling the connection with other components after rotation.

[0048] Optionally, reinforcing ribs are provided on the outer side of the catheter joint.

[0049] The ribs can significantly increase the structural strength of the conduit joint and prevent deformation under high pressure or high load conditions.

[0050] Optionally, reinforcing ribs are provided on the outer side of the locking ring.

[0051] The reinforcing ribs significantly increase the structural strength of the locking ring and prevent deformation under high pressure or load conditions.

[0052] Optionally, a protective sleeve is provided to seal the connection between the catheter connector and the implanted catheter.

[0053] The protective cover can isolate pollutants from the external environment and prevent bacteria, viruses or other impurities from entering the catheter system. The protective cover can buffer external impact or friction and reduce damage to the connection caused by external forces. The design of the protective cover can make the transition between the catheter and the connector smoother and reduce irritation or damage to surrounding tissues (such as blood vessel walls). By wrapping the connection, the protective cover can further fix the relative position of the catheter and the connector to prevent loosening.

[0054] Optionally, an expansion Luer interface is provided at the end of the expansion joint.

[0055] The Luer connector is a standardized connector widely used in medical and industrial fields with good compatibility and reliability. By setting up an expanded Luer connector, seamless connection with other Luer connector devices can be ensured.

[0056] Beneficial Effects

[0057] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0058] The technical solution provided by the present invention achieves safe catheterization through modular Luer interface, biomaterial upgrade and precision manufacturing process, and balances flexibility, durability and biosafety through structural innovation, providing an efficient and low-risk solution for medium- and long-term infusion therapy. It improves the convenience and accuracy of operation, strengthens safety and controls complications, and prolongs the indwelling time and optimizes functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 A structural cross-sectional view of a mini midline catheter proposed in an embodiment of the present invention;

[0060] Figure 2 A schematic structural diagram of a catheter sheath of a mini midline catheter proposed in an embodiment of the present invention;

[0061] Figure 3 A structural cross-sectional view of a catheter sheath of a mini midline catheter proposed in an embodiment of the present invention;

[0062] Figure 4 A schematic structural diagram of a dilatation sheath of a mini midline catheter proposed in an embodiment of the present invention;

[0063] Figure 5 A structural cross-sectional view of a dilatation sheath of a mini midline catheter proposed in an embodiment of the present invention;

[0064] 1. Catheter sheath; 11. Catheter connector; 12. Protective sleeve; 13. Implantation catheter; 2. Dilation sheath; 21. Dilation connector; 211. Rotating ring convex; 212. Dilation Luer interface; 213. Dilation ring convex; 22. Locking ring; 23. Dilation catheter; 3. Sheath tube. DETAILED DESCRIPTION

[0065] In order to further understand the content of the present invention, the present invention is described in detail in conjunction with the accompanying drawings and embodiments.

[0066] Example

[0067] Combined with Figure 1-4 A mini midline catheter comprises a catheter sheath 1, an expansion sheath 2 and a sheath tube 3. The catheter sheath 1 comprises a catheter connector 11, a protective sleeve 12 and an implanted catheter 13. The expansion sheath 2 comprises an expansion connector 21, a locking ring 22 and an implanted catheter 23. The catheter sheath 1 is wrapped around the outside of the expansion sheath 2. The implanted catheter 13 is wrapped around the outside of the expansion catheter 23. The length of the implanted catheter 23 is longer than that of the implanted catheter 13. The catheter connector 11 is connected to the locking ring 22 by a Luer lock. The inner wall of the locking ring 22 is provided with a thread groove, and the outer side of the catheter connector 11 is provided with a thread matching the thread groove. The locking ring 22 is sleeved on the outside of the expansion connector 21. The peripheral side of the expansion connector 21 is provided with an expansion ring protrusion 213 that is elastically clamped with the inner wall of the locking ring 22.

[0068] The implantable catheter 13 is made of a material with a biological risk assessment endpoint of Class B or above (long-term or permanent contact) with the circulating blood of an externally connected medical device. The expansion catheter 23 and the expansion joint 21 are connected by an injection molding and rubber coating process, and the implantable catheter 13 and the catheter joint 11 are connected by an injection molding and rubber coating process.

[0069] The implanted catheter 13 is made of TPU material. The catheter connector 11 is made of medical grade polycarbonate (PC) injection molding, and is provided with a Luer lock thread matching the locking ring 22 and radially distributed reinforcing ribs on the outside. The reinforcing ribs are 0.8mm high and 2mm wide, and the surface is knurled to enhance the grip friction. The catheter connector 11 and the implanted catheter 13 are seamlessly connected through the injection molding process, and an annular groove with a depth of 0.3mm is added to the encapsulation interface to enhance the bonding strength between the TPU material and the PC connector.

[0070] The implant catheter 13 is made of high-purity medical TPU (thermoplastic polyurethane) material, which meets the requirements of circulating blood contact level B in GB / T 16886.1 —2022 / ISO10993-1: 2018 standard, with an outer diameter of 1.6mm and an inner diameter of 1.0mm. The surface is treated with a hydrophilic coating to reduce friction resistance. The distal end of the catheter is pre-shaped with a 15° taper to facilitate directional advancement within the blood vessel.

[0071] The protective sleeve 12 is made of transparent silicone and is sleeved on the connection between the catheter connector 11 and the implanted catheter 13. The protective sleeve 12 is formed into an airtight package through a bonding process, thereby effectively protecting the catheter 13 and preventing reverse osmosis of body fluids or invasion of bacteria.

[0072] The dilatation catheter 23 is made of PEBAX® 7233 material (hardness 72D), 5 cm longer than the implantation catheter 13, with an outer diameter of 2.0 mm. The inner cavity is coated with a PTFE lubricating layer for guiding the guide wire into the blood vessel.

[0073] The main body of the expansion joint 21 is made of POM material, with an integrated expansion Luer interface 212 (compliant with ISO 80369-7 standard) at the end, and an expansion ring convex 213 (height 0.5mm, inclination 40°) is provided on the circumference, which is elastically engaged with the inner wall of the locking ring 22. An integrated rotating ring convex 211 is provided on the outer side, and wave-shaped friction ribs are distributed on the surface of the ring convex to facilitate the screwing operation.

[0074] The locking ring 22 is made of PP material, with a double-threaded groove (pitch 5mm) on the inner wall and axial reinforcing ribs (distributed at 90° intervals) on the outer side, which forms a Luer lock structure after being screwed together with the thread of the catheter connector 11.

[0075] The sheath tube 3 is made of transparent PE material, and its length matches that of the catheter sheath 1 , and is used to pre-package the catheter sheath 1 and the dilation sheath 2 assembly to avoid contamination during transportation or storage.

[0076] The expansion joint 21 is provided with a rotating annular protrusion 211 , and friction ribs are provided outside the rotating annular protrusion 211 .

[0077] The outer side of the conduit joint 11 is provided with reinforcing ribs. The outer side of the locking ring 22 is provided with reinforcing ribs.

[0078] A protective cover 12 is provided at the connection between the catheter connector 11 and the implanted catheter 13 for sealing.

[0079] An expansion Luer interface 212 is provided at the end of the expansion joint 21 .

[0080] Integrated locking design: The catheter connector 11 and the locking ring 22 are doubly locked by a threaded Luer lock + a Luer cone with a self-locking function, with a tightening torque of ≤0.5N·m and a pull-out force of ≥15N, taking into account both operational efficiency and the ability to resist accidental separation.

[0081] Biocompatibility guarantee: The cytotoxicity test (MTT method) of TPU implant catheter 13 meets the requirements of medium- and long-term indwelling.

[0082] Structural reliability: Peel strength of injection molding interface ≥25N / cm.

[0083] Operation process:

[0084] Puncture and guidewire placement:

[0085] Use an 18G puncture needle to percutaneously puncture the target blood vessel (such as the basilic vein). After confirming the blood return, send a 0.018-inch guide wire into the blood vessel through the puncture needle and withdraw the puncture needle.

[0086] If the skin at the puncture point is thick, use a scalpel to make a 2mm incision along the guide wire to reduce the resistance of the catheter passing through.

[0087] Catheter placement:

[0088] Remove the sheath tube 3, slowly push the catheter sheath 1 and dilation sheath 2 assembly along the guide wire, and use the rigid front end of the dilation catheter 23 to expand the subcutaneous tissue and blood vessel wall until the catheter sheath 1 enters the blood vessel to a predetermined depth (usually 10-15 cm).

[0089] The outer side of the locking ring 22 is squeezed with one hand to disengage the expansion ring protrusion 213 from the inner wall of the locking ring 22, and the catheter connector 11 is rotated in the reverse direction to unlock the Luer thread, and the guide wire and the expansion sheath 2 are pulled out, leaving only the catheter sheath 1 in the blood vessel.

[0090] Catheter fixing and connection:

[0091] Wipe off the blood at the puncture site and fix the catheter sheath 1 with a sterile dressing and a catheter fixing device containing a catheter fixing adhesive tape.

[0092] Tighten the infusion device (such as a positive pressure connector) and the catheter connector 11, flush the tube with saline to confirm patency, and then start infusion.

[0093] The present invention and its embodiments are described schematically above, and the description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by it and designs a structural method and an embodiment similar to the technical solution without creativity without departing from the purpose of the invention, they shall all fall within the protection scope of the present invention.

Claims

1. A mini midline catheter, characterized in that: It includes a catheter sheath, an expansion sheath and a sheath tube, the catheter sheath includes a catheter joint, a protective sleeve and an implanted catheter, the expansion sheath includes an expansion joint, a locking ring and an expansion catheter, the catheter sheath is wrapped around the outside of the expansion sheath, the implanted catheter is wrapped around the outside of the expansion catheter, the length of the expansion catheter is longer than that of the implanted catheter, the catheter joint is Luer-connected to the locking ring, the implanted catheter is made of a material with a biological risk assessment endpoint reaching a long-term or persistent contact level with circulating blood of an externally connected medical device, the expansion catheter and the expansion joint are connected by an injection molding and rubber-coating process, and the implanted catheter and the catheter joint are connected by an injection molding and rubber-coating process.

2. A mini midline catheter according to claim 1, characterized in that: The implant catheter is made of TPU material.

3. A mini midline catheter according to claim 1, characterized in that: The catheter connector is connected to the locking ring via a Luer lock.

4. A mini midline catheter according to claim 3, characterized in that: The inner wall of the locking ring is provided with a thread groove, and the outer side of the catheter connector is provided with a thread matching the thread groove.

5. A mini midline catheter according to claim 1 or 3, characterized in that: The locking ring is sleeved outside the expansion joint, and an expansion ring protrusion is provided on the peripheral side of the expansion joint to elastically engage with the inner wall of the locking ring.

6. The mini midline catheter according to claim 1, characterized in that: The expansion joint is provided with a rotating ring convexity, and friction ribs are arranged outside the rotating ring convexity.

7. The mini midline catheter according to claim 1, characterized in that: A reinforcing rib is arranged on the outer side of the conduit joint.

8. The mini midline catheter according to claim 1, characterized in that: The outer side of the locking ring is provided with reinforcing ribs.

9. The mini midline catheter according to claim 1, characterized in that: A protective sleeve is provided for sealing at the connection between the catheter joint and the implanted catheter.

10. The mini midline catheter according to claim 1, characterized in that: An expansion Luer interface is provided at the end of the expansion joint.

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