An arteriovenous cannulation structure

Abstract

This utility model relates to an arteriovenous cannulation structure, including a cannula body, a cannula core, a positioning ring, and a connector cap. The cannula body is sequentially connected from distal to proximal to a side-hole segment, a support segment, a clamping segment, and a connecting segment, and its inner cavity is a hollow, through-type structure. The distal end of the side-hole segment has a funnel-shaped constriction, and its sidewall has multiple side holes offset along the axial direction. The cannula core is inserted into the inner cavity of the cannula body, and its front end is a conical tip that smoothly transitions to the funnel-shaped constriction. The positioning ring is a hollow cylinder with a groove, which can move along the outer wall of the cannula body and be fixed by sutures. The connector cap is connected to the proximal end of the connecting segment. The funnel-shaped constriction design of this utility model significantly reduces the risk of tissue damage during vascular insertion, and the rounded corner structure avoids sharp edges scratching the vascular intima. The smooth transition between the conical tip of the cannula core and the funnel-shaped constriction reduces the resistance to cannulation and improves the cannula's ability to pass through narrowed blood vessels.

Description

Technical Field

[0001] This utility model relates to the field of medical device technology, and more specifically to an arteriovenous catheterization structure. Background Technology

[0002] In cardiovascular surgery, the cardiopulmonary bypass (CPB) system is a core life support device, and the performance of its cannulation system directly affects the success rate of the procedure. Current clinical applications of arteriovenous cannulation generally face the following technical bottlenecks:

[0003] 1. Traditional cannulation relies on the surgeon's experience for blind insertion, and the sharp angle design of the traditional cannula tip can easily cause damage to the vascular endothelium.

[0004] 2. Existing products use a single imaging marker, which has insufficient imaging resolution in complex anatomical locations (such as the aortic arch), resulting in some cases requiring secondary repositioning.

[0005] 3. The existing fixation ring has a smooth surface design, which increases the probability of suture slippage.

[0006] 4. The traditional straight-line arrangement of side holes (0° circumferential distribution) generates turbulent shear stress, which can easily lead to an increase in platelet activation rate.

[0007] Therefore, how to provide an arteriovenous cannulation structure to solve the above problems is a problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0008] This utility model aims to at least partially solve one of the aforementioned technical problems in the prior art.

[0009] Therefore, the purpose of this utility model is to propose an arteriovenous cannulation structure that first solves the problem that the sharp angle design of the traditional cannula tip is prone to causing damage to the vascular endothelium.

[0010] The technical solution of this utility model is an arteriovenous catheterization structure, comprising:

[0011] The cannula body is connected sequentially from the distal end to the proximal end with a side hole section, a support section, a clamping section and a connecting section, and its inner cavity is a hollow through structure; the distal end of the side hole section is provided with a trumpet-shaped constriction, and its side wall is provided with multiple side holes offset along the axial direction.

[0012] The cannula core is inserted into the cavity of the cannula, and its front end is a tapered tip, which smoothly transitions to the flared end.

[0013] The positioning ring is a hollow cylinder with a groove, which can move along the outer wall of the cannula and be fixed by the suture line;

[0014] A connector cap is attached to the proximal end of the connecting segment.

[0015] According to the arteriovenous cannulation structure of this utility model, the support section includes a spiral stainless steel wire inner layer and a polyurethane layer wrapped around it.

[0016] According to the arteriovenous cannula structure of this utility model, the length of the support section is 200-800mm, and the spacing of the steel wire spirals in the inner layer of the stainless steel wire is 1-5mm.

[0017] According to the arteriovenous cannulation structure of this utility model, the side hole segment has a built-in radiopaque barium strip with a length of 5-300mm, which solves the problem that existing products use a single imaging marker, which has insufficient imaging resolution in complex anatomical locations (such as the aortic arch), resulting in some cases requiring secondary position adjustments.

[0018] According to the arteriovenous cannulation structure of this invention, the side holes are staggered at intervals of 8-15 mm along the axial direction of the side hole segment, and are opened at 90° intervals in the circumferential direction. This solves the problem that the traditional straight arrangement of side holes (0° circumferential distribution) generates turbulent shear stress, which easily leads to an increase in platelet activation rate.

[0019] According to the arteriovenous catheter structure of this utility model, the rear end of the inner core of the catheter is a tailstock, and the center of the tailstock is provided with a friction hole. The diameter of the friction hole is 0.5-1.2mm and it is gap-fitted with the guidewire in the blood vessel.

[0020] According to the arteriovenous catheterization structure of this utility model, multiple grooves are arranged along the axial direction of the positioning ring, with a groove depth of 0.3-5mm and a width of 2-3mm, which solves the problem that the existing fixation ring adopts a smooth surface design, which increases the probability of suture slippage.

[0021] According to the arteriovenous catheter structure of this utility model, the connector cap is made of medical silicone material, and the inner wall is provided with a sealing ring, which is interference-fitted with the connecting section.

[0022] According to the arteriovenous cannula structure of this utility model, the taper of the trumpet-shaped constriction is 2°-5°, and the edge is a rounded corner structure with a rounded corner radius of 0.1-0.5mm.

[0023] As can be seen from the above technical solution, compared with the prior art, this utility model has the following beneficial effects:

[0024] 1. Structural optimization and enhanced safety: The trumpet-shaped constriction design at the distal end of the side hole section of this utility model significantly reduces the risk of tissue damage during blood vessel insertion, and the rounded corner structure avoids sharp edges scratching the vascular intima; the conical tip of the cannula core and the trumpet-shaped constriction transition smoothly, reducing the resistance to cannula pushing and improving the cannula's ability to pass through narrow blood vessels.

[0025] 2. Imaging and positioning accuracy: The side hole section of this utility model has a built-in barium strip, which improves the imaging resolution to more than 200μm under X-ray and reduces the positioning error rate to less than 5% (compared to 12%-15% for traditional cannulation).

[0026] 3. Enhanced mechanical properties: The support section adopts a composite structure of spiral stainless steel wire (1-5mm spacing) and polyurethane, which increases the compressive strength to 300mmHg without collapse and the torsional resistance reaches 180° bending without deformation.

[0027] 4. Fixing reliability: The axial groove (depth 0.3-5mm, width 2-3mm) of the positioning ring of this utility model improves the fixing strength of the suture and reduces the slippage rate.

[0028] 5. Hemodynamic optimization: Staggered distribution of side holes (axial spacing 8-15mm, circumferential 90° interval) reduces blood flow shear stress to 300 dyn / cm. 2 The following measures aim to reduce the risk of hemolysis (traditional inline distribution is 500 dyn / cm). 2 above).

[0029] 6. Ease of operation: The friction hole (0.5-1.2mm in diameter) of the cannula core fits the guidewire gap to reduce blood leakage.

[0030] 7. Sealing guarantee: The medical-grade silicone sealing ring of the connector cap (interference fit tolerance ±0.05mm) achieves IPX7 waterproof rating, preventing leakage at the connection point during extracorporeal circulation. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0032] Figure 1 A schematic diagram of an arteriovenous cannulation structure provided by this utility model;

[0033] Figure 2 The schematic diagram shows the structure of the side hole section and the support section;

[0034] Figure 3 The schematic diagram of the cannula core is shown;

[0035] Figure 4 The diagram shows a cross-sectional view of the tailstock of the cannula core;

[0036] Figure 5The diagram shows a cross-sectional view of the inner layer of the stainless steel wire.

[0037] In the diagram: 1 is the cannula body; 2 is the cannula core; 3 is the positioning ring; 4 is the connector cap; 11 is the side hole section; 111 is the side hole; 12 is the support section; 13 is the clamping section; 14 is the connecting section; 112 is the trumpet-shaped end; 113 is the barium strip; 121 is the inner layer of the stainless steel wire; 21 is the conical tip; 211 is the conical tip inlet; 22 is the tailstock; 221 is the friction hole; 222 is the intravascular guidewire; 31 is the groove. Detailed Implementation

[0038] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.

[0039] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "far", "near", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0040] Traditional cannulation relies on the surgeon's experience for blind insertion, and the sharp-angled design of the cannula tip (incision design) easily causes endothelial damage. Furthermore, the use of a single contrast marker provides insufficient contrast resolution in complex anatomical locations (such as the aortic arch), often requiring repositioning in some cases. In addition, the smooth surface design of existing fixation rings increases the probability of suture slippage. The traditional linear arrangement of side holes (0° circumferential distribution) generates turbulent shear stress, which can easily lead to increased platelet activation.

[0041] In view of this, the technical solution of this utility model provides an arteriovenous cannulation structure, see appendix. Figure 1 and 3 It includes: cannula body 1, cannula inner core 2, positioning ring 3 and connector cap 4;

[0042] The cannula body 1 is connected sequentially from distal to proximal by a side hole section 11, a support section 12, a clamping section 13, and a connecting section 14, and its inner cavity is a hollow through structure; the distal end of the side hole section 11 is provided with a trumpet-shaped constriction 112, and its side wall is provided with multiple side holes 111 offset along the axial direction; the cannula core 2 is inserted into the inner cavity of the cannula body 1, and its front end is a conical tip 21, and the conical tip 21 smoothly transitions with the trumpet-shaped constriction 112; the positioning ring 3 is a hollow cylinder with a groove 31 on it, which can move along the outer wall of the cannula body 1 and be fixed by a suture; the connector cap 4 is connected to the proximal end of the connecting section 14.

[0043] It is worth noting that in this utility model, "far end" and "near end" are relative to the operating end, that is, the far end and the near end relative to the operating end.

[0044] The trumpet-shaped constriction design at the distal end of the side hole section of the present invention significantly reduces the risk of tissue damage during blood vessel insertion, and the rounded corner structure avoids sharp edges scratching the vascular intima; the conical tip of the cannula core smoothly transitions to the trumpet-shaped constriction, reducing the resistance to cannula pushing and improving the cannula's ability to pass through narrow blood vessels.

[0045] In the above embodiments, the taper of the flared opening 112 is 2°-5°, and the edges are rounded with a radius of 0.1-0.5mm.

[0046] Advantageously, the support section 12 comprises a spiral stainless steel wire inner layer 121 and an outer polyurethane layer; the support section 12 has a length of 200-800 mm, and the spiral spacing of the stainless steel wire inner layer 121 is 1-5 mm. See Appendix. Figure 5 The polyurethane layer is not shown in the diagram. As a result, the compressive strength is improved, it does not collapse, and its torsional resistance reaches 180° without deformation.

[0047] In an embodiment of this utility model, the side hole section 11 contains a non-transmissive barium strip 113 with a length of 5-300mm; thereby, the X-ray imaging resolution is improved to over 200μm and the positioning error rate is reduced to less than 5%.

[0048] In this utility model, see appendix. Figure 2 The side holes 111 are staggered at intervals of 8-15mm along the axial direction of the side hole section 11 and are opened at 90° intervals in the circumferential direction; this reduces blood flow shear stress and reduces the risk of hemolysis.

[0049] See appendix Figure 4 The rear end of the cannula core 2 is a tailstock 22. The tailstock 22 has a friction hole 221 at its center. The diameter of the friction hole 221 is 0.5-1.2 mm and it fits with the guide wire 222 in the blood vessel to reduce blood leakage.

[0050] Explanation of the effect of the friction hole and the gap fit between the guide wire 222 and the blood vessel on reducing blood leakage:

[0051] According to the Hagen-Poiseuille law, flow rate is directly proportional to the fourth power of the radius. By controlling the friction orifice diameter to 0.5-1.2 mm (radius 0.25-8nL0.6 mm), leakage is reduced by more than 75% compared to the traditional open orifice design (orifice diameter 22 mm). Furthermore, the narrow annular gap (5-50 pm between the guidewire and the orifice wall) promotes laminar blood flow (Reynolds number Re < 2000), avoiding sudden increases in flow rate caused by turbulence, thereby reducing blood leakage.

[0052] In addition, the friction hole 221 can also be made of an elastic material. When the metal intravascular guide wire is inserted into the friction hole 221, the elastic deformation of the material will wrap the metal intravascular guide wire, thereby achieving a sealing effect and preventing the patient's blood from flowing out during the insertion process.

[0053] Advantageously, multiple grooves 31 are arranged along the axial direction of the positioning ring 3, with a groove depth of 0.3-5 mm and a width of 2-3 mm. This improves the fixation strength of the suture and reduces the slippage rate.

[0054] The connector cap 4 is made of medical silicone and has a sealing ring on its inner wall, which is press-fitted with the connecting section 14.

[0055] In this invention, the preparation of arteriovenous cannulas is as follows:

[0056] The cannula body 1 is formed, and the side hole section 11 is injection molded with medical-grade polyurethane with a Shore hardness of 90A. The distal end is machined with a flared taper of 3° and a rounded corner radius of 0.1mm. The side holes 111 are laser-cut with an axial spacing of 8mm and a circumferential 90° staggered distribution. The embedded barium strip 113 is 4mm wide and has the same length as the side hole section.

[0057] Support section 12 consists of 0.2mm diameter 304 stainless steel wire wound around a mandrel with a spiral spacing of 0.7mm, and an outer layer of 0.5mm thick polyurethane coating. After curing, it forms a hollow composite structure with a total length of 500mm.

[0058] Clamping section 13 and connecting section 14: respectively made of medical-grade polyurethane and medical-grade polycarbonate injection molding. Connecting section 14 has an outer diameter of 11mm and is equipped with standard Luer joint threads.

[0059] The cannula core 2 is manufactured using medical-grade polyvinyl chloride injection molding. The front end has a tapered tip 21 with a taper angle of 7°. The tailstock 22 has a friction hole 221 with a diameter of 0.10 mm, which is matched with the guide wire diameter of 0.97 mm with a clearance tolerance of ±0.05 mm.

[0060] The positioning ring 3 and the connector cap 4 are injection molded from liquid silicone. The inner wall of the connector cap 4 has an annular protrusion with a height of 0.2mm, and the interference fit with the connecting section 14 is 0.1mm.

[0061] In this utility model, unless otherwise explicitly specified and limited, the terms "installation", "connection", "joining", "fixing", etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0062] Clinical application method of this utility model: Under cannulation guidance, the operator holds the arteriovenous cannula support section 12 and inserts the conical tip inlet 211 of the cannula core into the intravascular guidewire 222 until the intravascular guidewire 222 exits through the friction hole 221 of the cannula core tail seat. The use of the friction hole and guidewire reduces blood leakage during insertion into the blood vessel, thus reducing the risk of blood loss. The intravascular guidewire 222 is percutaneously inserted into the target blood vessel. The conical tip 21 of the cannula core and the funnel-shaped constriction 112 of the arteriovenous cannula enter the blood vessel sequentially. The smooth transition between the conical tip 21 and the funnel-shaped constriction 112 facilitates insertion into the blood vessel and reduces vascular injury. The friction hole 221 of the cannula core 2, in conjunction with the guidewire, pushes the cannula body 1 to the barium strip 113 imaging position of the side hole section 11. After positioning and fixing, and confirming by X-ray that the side hole segment 11 has reached the target position, remove the guidewire and cannula core 2, slide the positioning ring 3 to the vascular puncture point, and fix it by wrapping the groove 31 with 3-0 polypropylene suture. Connect the extracorporeal circulation system, remove the connector cap 4, connect the connecting segment 14 to the CPB tubing, and leave a hemostatic forceps interface at the clamping segment 13 to control blood flow.

[0063] Performance testing:

[0064] Mechanical testing: Support section 12 did not collapse under a negative pressure of 300 mmHg, and its bending resistance meets the ASTM F2606 standard.

[0065] Development test: The barium strip 113 showed a clear development under DSA imaging that met the DIN 6868-157 standard.

[0066] Fluid testing: The 111 side hole distribution design improves blood flow uniformity by 30% and reduces turbulent energy loss to below 5%.

[0067] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0068] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. An arteriovenous cannulation structure, comprising: include: The cannula body (1) is connected in sequence from the distal end to the proximal end with a side hole section (11), a support section (12), a clamping section (13) and a connecting section (14), and its inner cavity is a hollow through structure; the distal end of the side hole section (11) is provided with a trumpet-shaped constriction (112), and its side wall is provided with multiple side holes (111) offset along the axial direction; The cannula core (2) is inserted into the inner cavity of the cannula body (1), and its front end is a conical tip (21), and the conical tip (21) smoothly transitions with the trumpet-shaped constriction (112); The positioning ring (3) is a hollow cylinder with a groove (31) on it, which can move along the outer wall of the cannula body (1) and be fixed by the suture line; A connector cap (4) is attached to the proximal end of the connecting segment (14).

2. The arteriovenous cannulation structure of claim 1, wherein The support section (12) includes a spiral stainless steel wire inner layer (121) and a polyurethane layer wrapped around it.

3. The arteriovenous cannulation structure of claim 2, wherein, The length of the support section (12) is 200-800mm, and the spacing between the steel wire spirals of the inner layer (121) of stainless steel wire is 1-5mm.

4. The arteriovenous cannulation structure of claim 1, wherein The side hole section (11) contains a non-transmissive barium strip (113) with a length of 5-300 mm.

5. The arteriovenous cannulation structure of claim 1, wherein, The side holes (111) are staggered at intervals of 8-15mm along the axial direction of the side hole section (11) and are opened at 90° intervals in the circumferential direction.

6. The arteriovenous cannulation structure of claim 1, wherein The rear end of the cannula core (2) is a tailstock (22), and the center of the tailstock (22) is provided with a friction hole (221). The diameter of the friction hole (221) is 0.5-1.2mm, and it is in interlocked with the guidewire (222) in the blood vessel.

7. The arteriovenous cannulation structure of claim 1, wherein Multiple grooves (31) are arranged along the axial direction of the positioning ring (3), with a groove depth of 0.3-5mm and a width of 2-3mm.

8. The arteriovenous cannulation structure of claim 1, wherein The connector cap (4) is made of medical silicone and has a sealing ring on its inner wall, which is press-fitted with the connecting section (14).

9. The arteriovenous cannulation structure of any one of claims 1-8, wherein, The flared opening (112) has a taper of 2°-5° and rounded edges with a radius of 0.1-0.5mm.

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