A dual lumen fistula access device for maintenance hemodialysis and methods of use thereof

Abstract

This invention relates to a dual-lumen arteriovenous fistula puncture device for maintenance hemodialysis and its method of use, aiming to solve the problems of pain during traditional double-needle puncture, difficulty in puncture for patients with poor vascular conditions, and high blood recirculation rate. The device includes an integrated needle hub and a puncture tubing. The tubing contains independent first fluid channels (venous return segment) and second fluid channels (arterial drainage segment). The venous return segment has return side holes on its sidewall, and the arterial drainage segment has multiple axially distributed drainage side holes, with an axial distance of ≥3cm between the two segments. The total area of ​​the drainage side holes is larger than the cross-sectional area of ​​the channel, and the opening directions of the venous and arterial side holes are staggered. This invention achieves dual arterial and venous access through a single puncture. Combined with optimized fluid dynamics design, it significantly reduces the blood recirculation rate (≤5%) and improves the puncture success rate for patients with poor vascular conditions (≥85%), while also offering the advantages of low pain and high dialysis efficiency.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a puncture needle for arteriovenous fistula in maintenance hemodialysis patients. Background Technology

[0002] Arteriovenous fistulas (AVFs) are permanent vascular access points established for long-term hemodialysis in patients with end-stage renal disease (ESRD). They are created by directly anastomosing an artery to an adjacent vein (or connecting it via a segment of autologous / artificial blood vessel), arterializing the superficial vein (increasing blood flow and diameter) to meet the needs of repeated punctures and sufficient blood flow during dialysis. Due to their superior patency, low infection rate, and low cost, AVFs are widely recognized as a "lifeline" for maintenance hemodialysis patients, with a clinical recommendation rate exceeding 80% in my country.

[0003] Currently, the traditional double-needle puncture method is commonly used in clinical practice for hemodialysis, which involves three punctures per week. Each time, two large-diameter (usually 15-16G) metal needles are inserted into the patient's arteriovenous fistula.

[0004] This method has several serious drawbacks: First, repeated punctures cause severe pain for patients, and long-term accumulation can easily lead to psychological problems such as anxiety and depression, seriously affecting their quality of life. Second, for patients with comorbidities such as diabetes and hypertension resulting in poorly developed arteriovenous fistulas, thin blood vessels, or insufficient length, successfully completing double-needle punctures is extremely difficult, and may even fail to establish an effective vascular access, leading to inadequate dialysis or forcing the use of suboptimal access methods such as central venous catheters, increasing the risk of infection and thrombosis. Furthermore, with the two needles located at different points in the blood vessel, the close proximity may cause "blood recirculation," meaning that already dialyzed blood is reintroduced into the arterial end, reducing dialysis efficiency and treatment effectiveness.

[0005] To alleviate the pain of puncture, existing technologies include dialysis using a single indwelling needle. However, these are usually single-lumen structures that can only achieve blood flow in one direction, and still require the use of another needle or tubing, thus not fundamentally solving the problem of double-needle puncture.

[0006] Other designs attempt to set up multiple chambers within a single needle, but they have significant shortcomings in terms of functional definition of arterial and venous segments, spacing control, and hemodynamic optimization, failing to effectively address the core pain points of recirculation and high puncture difficulty.

[0007] Therefore, developing a novel dialysis puncture device that enables single-puncture, reduces recirculation, and is suitable for patients with poor vascular conditions has significant clinical and market value. Summary of the Invention

[0008] This invention aims to overcome the shortcomings of existing technologies and provide a dual-lumen arteriovenous fistula puncture device for maintenance hemodialysis and its method of use. This device can simultaneously establish two independent blood pathways—arterial drainage and venous return—with a single puncture, aiming to solve key technical problems such as the significant pain caused to patients by traditional double-needle puncture, difficulty in puncture for patients with poor vascular conditions, and high blood recirculation rates.

[0009] The technical solution adopted by this invention to solve its technical problem is: A dual-lumen arteriovenous fistula puncture device for maintenance hemodialysis is constructed, comprising an integrated needle hub and a puncture tubing. The puncture tubing is made of a flexible biocompatible material and has an internally independent first fluid channel and a second fluid channel. The front end of the first fluid channel extends into a venous return segment, and its sidewall is provided with at least one return side hole. The front end of the second fluid channel extends into an open arterial drainage segment, and its sidewall is provided with at least four drainage side holes spaced axially along its side. The axial distance between the starting end of the arterial drainage segment and the front end face of the venous return segment is greater than or equal to 3 cm. The sum of the total cross-sectional areas of the drainage side holes is greater than the inner cross-sectional area of ​​the second fluid channel. The venous return segment is used to connect to the venous circuit of the dialysis machine to receive blood from the venous end of the fistula; the arterial drainage segment is used to connect to the arterial circuit of the dialysis machine to drain blood from the arterial end of the fistula.

[0010] Furthermore, the opening direction of the blood return side hole on the side wall of the venous blood return segment is spatially offset from the opening direction of the blood drainage side hole on the side wall of the arterial blood drainage segment, so as to reduce the mixing of blood near the puncture point.

[0011] Furthermore, the number of blood-draining side holes is 4 to 8, and the shape of each blood-draining side hole is circular, elliptical or polygonal, and all of them face the same circumferential tangent direction or spiral distribution direction of the arterial blood-draining segment.

[0012] Furthermore, the length of the arterial blood-draining segment is greater than or equal to 2 cm, and the blood-draining side holes on its sidewall are evenly distributed along the axial direction, with a spacing of 0.2 to 0.5 cm between adjacent side holes.

[0013] Furthermore, the puncture tubing has an overall tapered or stepped tapering structure, with its outer diameter gradually decreasing from the connection point with the integrated needle hub to the distal puncture tip, and the taper is 1:50 to 1:100.

[0014] Furthermore, the integrated needle hub is provided with Luer connectors that are respectively connected to the first fluid channel and the second fluid channel, and the two sides of the integrated needle hub extend outward to form at least one pair of elastic fixing wings, the surface of which is provided with anti-slip texture.

[0015] Furthermore, it also includes a puncture needle core, which is slidably inserted into the lumen of the puncture tubing to provide rigid support for the puncture tubing during puncture. The tip of the puncture needle core extends out of the distal opening of the puncture tubing and can be removed from the integrated needle hub after successful puncture.

[0016] Furthermore, the wall thickness of the puncture tubing is unevenly distributed along its length, with a wall thickness of 0.1 to 0.2 mm at the arterial blood intake section and the venous blood return section, and a wall thickness of 0.2 to 0.3 mm in the remaining sections.

[0017] Furthermore, a peelable protective sheath is provided on the proximal end of the puncture tube, the length of which covers at least 5 cm of the puncture tube excluding the puncture tip, and the sheath is made of medical-grade polyethylene.

[0018] A method for maintenance hemodialysis using the above-mentioned device includes the following steps: S1: Inserting the puncture tubing of the device into the vicinity of the arterial end of the patient's arteriovenous fistula with the assistance of the puncture needle core, ensuring that the arterial blood-drawing segment is located in the arterial segment of the fistula and the venous blood-returning segment is located in the venous segment of the fistula, and that the axial distance between the two is greater than or equal to 3 cm; S2: Removing the puncture needle core, leaving only the puncture tubing in the fistula vessel; S3: Connecting the first fluid channel to the venous circuit of the dialysis machine through the first Luer connector, and connecting the second fluid channel to the arterial circuit of the dialysis machine through the second Luer connector; S4: Starting the dialysis machine, drawing arterial blood through the side hole of the arterial blood-drawing segment, and after dialysis treatment, returning the blood to the venous end through the side hole of the venous blood-returning segment, thus completing a single puncture hemodialysis treatment.

[0019] Compared with the prior art, the present invention has the following significant advantages: 1. Revolutionary reduction of patient pain: By replacing the traditional double-needle puncture with a single puncture, the number of punctures and pain for patients are greatly reduced, effectively alleviating patients' anxiety and significantly improving the dialysis experience and quality of life; 2. Overcoming puncture difficulties and expanding the scope of application: The design of a single long needle can flexibly cover a longer blood vessel distance, solving the clinical problem of "not being able to find two needle holes" for patients with immature blood vessel development and insufficient length, enabling more patients to use the ideal arteriovenous fistula for dialysis. 3. Significantly reduce blood recirculation and improve dialysis quality: Through a number of synergistic techniques, such as strictly controlling the distance between arteriovenous segments (≥3cm) and staggering the opening directions of arteriovenous side holes, blood recirculation is minimized, ensuring the adequacy and effectiveness of dialysis and improving treatment outcomes. 4. Optimize hemodynamics to ensure safety and efficiency: The design of the total area of ​​the blood-drawing side hole being larger than the cross-sectional area of ​​the channel ensures that blood can be introduced in a low-resistance and stable manner, avoiding the risk of vascular damage or coagulation caused by excessive negative pressure or rapid blood flow. 5. Improved ease of operation and patient comfort: The design details such as the material of the tubing, the tapered structure, and the elastic fixation wings improve the success rate of puncture, the ease of operation, and the overall comfort of patients during dialysis. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort: Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention; Figure 2 This is a schematic diagram of the axial cross-sectional structure of the front end portion of the puncture tube in an embodiment of the present invention; Figure 3 This is a schematic diagram of the puncture needle core in an embodiment of the present invention; Figure 4 This is a schematic diagram illustrating the relationship between the puncture needle core and the puncture tubing in an embodiment of the present invention.

[0021] In the diagram, the markings are: 1-integrated needle hub; 11-first Luer connector; 12-second Luer connector; 13-fixation wing; 2-puncture tubing; 21-first channel; 211-venous return segment; 2111-return side hole; 22-second channel; 221-arterial blood draw segment; 2211-blood draw side hole; L-distance between the beginning of the arterial blood draw segment and the front end of the venous return segment; 4-puncture needle core; 41-tip. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, a clear and complete description will be provided below in conjunction with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0023] In one embodiment of the present invention, a dual-lumen arteriovenous fistula puncture device for maintenance hemodialysis is provided, referring to... Figures 1 to 4The device includes: an integrated needle hub 1; a puncture tubing 2 made of a flexible biocompatible material, with an independent first fluid channel 21 and a second fluid channel 22 inside; the front end of the first fluid channel 21 extends into a venous return segment 211, and its side wall has at least one return side hole 2111; the front end of the second fluid channel 22 extends into an open arterial drainage segment 221, and its side wall has at least four axially spaced drainage side holes 2211; the axial distance L between the starting end of the arterial drainage segment 221 and the front end face of the venous return segment 211 is ≥3cm; the venous return segment 211 is used to connect to the venous circuit of the dialysis machine to receive blood from the venous end of the arterial fistula, and the arterial drainage segment 221 is used to connect to the arterial circuit of the dialysis machine to drain blood from the arterial end of the arterial fistula; the sum of the total cross-sectional areas of the drainage side holes 2211 is greater than the inner cross-sectional area of ​​the second fluid channel 22. The venous return segment 211 is used to connect to the venous circuit of the dialysis machine to receive blood from the venous end of the fistula; the arterial drainage segment 221 is used to connect to the arterial circuit of the dialysis machine to drain blood from the arterial end of the fistula.

[0024] This embodiment combines the functions of two traditional puncture needles into one through a design of "one flexible tube, two independent channels, specific functional segments, and physical spacing isolation." Furthermore, through fluid dynamics optimization, it achieves efficient and low-consumption hemodialysis in a single puncture. Specifically, it includes: 1. Dual-channel independent drainage, replacing the physical separation of two needles: The puncture catheter is designed with two completely independent fluid channels (the first channel for venous return and the second channel for arterial drainage). This is functionally equivalent to the traditional method of using two separate puncture needles to connect the arterial and venous circuits, but physically combined into one. This fundamentally solves all the problems associated with "double needles".

[0025] 2. Functional segmentation design enables precise collection and extraction of arterial and venous blood: Arterial blood intake segment (open end + multiple side holes): This segment is open at the front end and has multiple side holes on the side wall. Under the influence of blood pressure, blood from the arterial end is naturally "drawn" into the second channel through these side holes and delivered to the arterial pump of the dialysis machine to begin the dialysis purification process. The multiple side holes are designed to disperse blood flow and avoid vascular collapse or blood turbulence caused by single-point aspiration.

[0026] 3. Fluid isolation principle for critical spacing (≥3cm): This is the core of reducing "blood recirculation." Blood recirculation refers to the phenomenon where "clean" blood that has already been dialyzed does not return to the heart to participate in systemic circulation, but is instead re-drawn into the adjacent arterial needle. By forcibly setting the physical distance between the arterial blood draw segment and the venous blood return segment within the blood vessel to ≥3cm, it is ensured that blood drawn from the arterial segment must first flow through a relatively long blood vessel (back to the heart, through pulmonary circulation, and then to the systemic arterial system) before reaching the location of the venous segment. This distance is sufficient for the blood to complete one effective systemic circulation, thereby physically greatly reducing the occurrence of recirculation and ensuring dialysis efficiency.

[0027] 4. Total area of ​​blood drainage side holes > cross-sectional area of ​​the channel (flow optimization principle): According to the continuity equation in fluid mechanics (Q=A*v), to introduce sufficient blood flow (Q) per unit time, a high flow velocity (v) is required if the cross-sectional area (A) of the channel is small. Designing the total area of ​​the blood-drawing side holes to be larger than the internal cross-sectional area of ​​the channel itself means that blood passes through an "expanded" collection area before entering the narrow channel. This effectively reduces the flow velocity and resistance when blood enters the channel, making the blood flow smoother and more stable. It also reduces the risk of blood components (such as blood cells) being damaged by high-speed impact (hemolysis) and the possibility of platelet aggregation forming thrombi.

[0028] Based on the above principles, the solutions described in the above embodiments offer the following significant advantages: 1. For patients: It greatly reduces pain and improves quality of life. Reduce the number of punctures: from 6 punctures per week to 2 punctures per week (assuming a puncture is changed every time dialysis is performed), significantly reducing puncture pain and anxiety.

[0029] Reduced puncture difficulty: For patients with short, thin, or hardened blood vessels, a long needle makes it easier to find a suitable puncture point and path, solving the clinical problem of "not being able to insert two needles" and expanding the applicable population for arteriovenous fistulas.

[0030] Improved comfort: The soft tubing material allows for easy removal of the needle core after puncture, avoiding discomfort and potential damage caused by the movement of a rigid needle within the blood vessel.

[0031] 2. In terms of medical outcomes: Improves dialysis quality and ensures treatment safety. Significantly reduces blood recirculation rate: The spacing of ≥3cm and the multi-side hole design can reduce the recirculation rate from 15-20% in traditional double needle dialysis to below 5%, ensuring adequate dialysis and improving patient survival.

[0032] Ensuring stable and safe blood flow: The optimized side-hole design avoids high-speed blood flow and turbulence, reduces the risk of hemolysis and coagulation, and improves the safety of the treatment process.

[0033] 3. For clinical procedures: Simplify processes and improve efficiency. Simplified puncture procedure: Single puncture operation, shortening puncture time, reducing the workload and technical difficulty for nurses.

[0034] Reduced risk of complications: By reducing the number of puncture sites on the blood vessel wall, the incidence of long-term complications such as pseudoaneurysm and vascular stenosis can theoretically be reduced.

[0035] In a further embodiment, the opening direction of the blood return side hole 2111 on the side wall of the venous blood return segment 211 and the opening direction of the blood drainage side hole 2211 on the side wall of the arterial blood drainage segment 221 are spatially offset from each other to reduce blood mixing near the puncture point and reduce the recirculation rate from the source. Intervening in the blood flow mixing path through "spatial guidance" has the advantage of acting as an "enhancer" for the aforementioned embodiments, further eliminating the last possibility of blood recirculation at the microscopic level, pushing the precision and efficiency of dialysis to a new level.

[0036] Specifically, this is reflected in: 1. Breaking the "proximity mixing" path: Even if the arterial blood intake segment and the venous blood return segment maintain a distance of ≥3cm within the blood vessel, they are both located within the same relatively narrow vascular lumen. Without any guidance, blood drawn from the arterial side hole (blood about to be dialyzed) and blood returning from the venous side hole (blood that has already been dialyzed) may "short-circuit" and mix within the vascular lumen, or even in the narrow space around the needle.

[0037] 2. Guide blood flow path by opening direction: By deliberately designing the side holes of the arterial blood outflow section and the venous blood return section to "look" in different directions (for example, the arterial hole faces the left front and the venous hole faces the right upper), it is equivalent to setting different "exit" directions for the two blood flows.

[0038] Arterial blood is "guided" to enter the catheter in one direction.

[0039] Venous blood is "guided" to enter the catheter in another direction.

[0040] In this way, the two blood flows are separated in their "territory" within the blood vessel lumen before leaving the blood vessel and entering the catheter, greatly reducing the chance of them meeting and mixing directly near the puncture point.

[0041] 3. Transfer the mixing area from "inside the blood vessel" to "extracorporeal dialysis tubing": Ideally, the only mixing point between arterial and venous blood should be inside the dialyzer, where the exchange of substances takes place. To ensure that blood that should not be mixed in advance is kept as separate as possible at the "source" of the blood vessel before entering the catheter and joining the dialysis machine.

[0042] In a further embodiment, the device has 4 to 8 blood-draining side holes 2211, each of which is circular, elliptical, or polygonal in shape, and all facing the same circumferential tangent or spiral distribution direction of the arterial blood-draining segment 221. The shape and distribution direction design disperses the blood flow impact force, reducing the risk of local coagulation. Through the three-dimensional hydrodynamic optimization of the number, shape, and direction of the blood-draining side holes, a simple "blood inlet" is transformed into a highly efficient, stable, and safe "blood flow collection system." Its advantage lies in transforming dialysis puncture from a passive "invasive procedure" into an active protection that "gently treats" the patient's blood vessels, representing a model of high-value medical device design.

[0043] To avoid the "single-point suction" effect: If there is only one large side hole, the strong negative pressure will be concentrated at one point, like a "suction cup," which may cause the vascular intima at that point to be sucked up, collapse, or even damage the blood vessel. Multiple small holes distribute the suction force evenly in one area, greatly reducing the local pressure on the blood vessel wall and the risk of damage.

[0044] Adapting to vascular pulsation: Blood flow in the arterial fistula is pulsatile. Multiple side holes are equivalent to providing multiple "inlets," ensuring that regardless of which phase of the cardiac cycle the blood vessel is constricting or dilating, some side holes are always in the optimal position for blood flow, thus guaranteeing the continuity and stability of blood flow and avoiding fluctuations or interruptions in blood flow caused by pulsation.

[0045] The principle of "low resistance and strength" balance for specific shapes (circles, ellipses, polygons): Circular holes: This is the most classic shape, offering uniform stress distribution, minimal fluid resistance, and relatively simple manufacturing. Elliptical / polygonal holes: These may have a larger perimeter or stronger edges within the same projected area. This helps improve the strength of the hole edges, preventing deformation or tearing under high-pressure blood flow impact, and can also alter the vortex pattern of blood flow to some extent. Choosing multiple shapes gives designers the flexibility to optimize based on specific blood flow parameters.

[0046] The principle of "flow guidance and rectification" with a unified orientation (circumferential tangent or helical direction): Tangential direction of the circumference: Imagine the spokes of a wheel. All the openings of the side holes are aligned "tangentially" along the cross-section of the artery. This ensures that the blood flow introduced through each hole is parallel to or at an angle to the vessel's centerline, rather than spraying directly at the vessel wall. This effectively prevents blood flow from directly impacting the inner wall of the opposite side of the vessel, reducing turbulence and intimal damage.

[0047] Spiral distribution direction: This is a more advanced optimization. The openings of the side holes are arranged in a spiral pattern along the length of the arterial drainage segment. This design adds a rotational component (angular momentum) to the blood flow entering the catheter, forming a stable flow pattern similar to a "vortex." This vortex is more resistant to external disturbances than a straight flow, further stabilizing blood flow, reducing hemolysis (red blood cell rupture), and platelet activation, resulting in smoother blood flow within the catheter.

[0048] The multi-port design ensures a continuous and stable introduction of sufficient blood under various vascular conditions and pulsation, meeting the needs of high-flux dialysis. Distributed drainage avoids "single-point attack" on the vessel wall, and the combination of tangential / spiral guidance reduces direct impact on the vessel wall, thereby lowering the risk of long-term complications such as vasospasm, intimal injury, thrombosis, and pseudoaneurysm. By guiding blood flow to form stable laminar or vortex flow, the intensity of collisions between blood cells and the catheter wall and themselves is reduced, effectively lowering the risks of hemolysis (leading to anemia) and coagulation (leading to thrombosis), making the dialysis process safer. This solution is not simply about "adding more ports," but rather a comprehensive consideration of fluid dynamics optimization in terms of quantity, shape, and arrangement direction. In particular, the "spiral distribution" design reflects the inventor's profound understanding of blood fluid properties and superior design skills, possessing strong non-obviousness and providing strong support for the patent's inventiveness.

[0049] In a further embodiment, refer to Figures 1 to 4 The arterial blood-drawing segment 221 of the device has a length ≥2cm, and the blood-drawing side holes 2211 on its sidewall are evenly distributed along the axial direction, with a spacing of 0.2-0.5cm between adjacent side holes. This length and spacing design ensures uniform blood flow intake and avoids excessive local negative pressure leading to vascular collapse. By defining the arterial blood-drawing segment from a vague "long segment" into a "functional organ" with precise geometric parameters, scientific sizing ensures that its internal multi-side hole system can work collaboratively like a precision instrument, achieving efficient, stable, and safe blood flow capture. Its advantage lies in transforming innovative concepts into quantifiable, producible, and verifiable high-quality standards, representing a crucial step in moving this solution from "usable" to "easy to use and durable."

[0050] Its core principle is to construct a "high-efficiency blood flow capture zone" with appropriate length and balanced aperture positions to adapt to human physiological parameters and achieve the best blood traction effect.

[0051] 1. The principle of "spatial containment and coverage" for lengths ≥ 2 cm: Provide sufficient space for side hole arrangement: As mentioned in the previous embodiments, the number of blood drainage side holes is 4-8. To reasonably arrange these holes on the arterial blood drainage segment and ensure the spacing between them (further limited to 0.2-0.5cm), a minimum length is required. A length of ≥2cm ensures that there is enough physical space in the design to realize multiple side holes and optimal spacing, avoiding excessive crowding between holes.

[0052] Adapting to vessel diameter and optimizing blood flow distribution: The lumen diameter of arteriovenous fistulas such as the radial artery in the human body is typically around 2-4 mm. A 2 cm long drainage segment has side holes that can cover a considerable distance within the vessel lumen. This ensures that regardless of the vessel's eccentricity during pulsation (i.e., the vessel's centerline does not perfectly coincide with the needle's centerline), a portion of the side holes will always be aligned with or close to the center of blood flow, thus guaranteeing that drainage efficiency will not drastically decrease due to slight vessel swaying. It's like an "extended catcher's glove," providing wider coverage.

[0053] 2. The principle of "load balancing" with uniform axial distribution: Distributing multiple side holes evenly along the length of the arterial drainage segment means that the drainage task is "distributed" across the entire drainage segment. This avoids the situation where all the holes are crowded into a small section, leading to excessive local blood flow pressure while other areas remain idle. It ensures that blood flow is introduced into the catheter evenly and smoothly throughout the entire blood vessel, further reducing the risk of damage to local blood vessels due to overload.

[0054] 3. The principle of "anti-interference and coordination" with a spacing of 0.2-0.5 cm: Avoid "airflow interference" between holes: If two holes are too close (less than 0.2 cm), their respective blood flow fields may overlap and interfere with each other, forming unstable turbulence, which will reduce the blood flow efficiency of a single hole and increase the shear force on the blood vessel wall.

[0055] To maximize synergy: a spacing of 0.2-0.5cm is the optimized "sweet spot". At this distance, the drainage areas of each hole can effectively cover the entire length of the arterial drainage segment, while also working independently and collaboratively to form a smooth, continuous low-pressure drainage area, rather than a series of isolated "pits" that may cause turbulence.

[0056] Adapting to vascular physiology: This spacing range also matches the pulsating wavelength and blood flow velocity of common arteriovenous fistula vessels, ensuring that an appropriate number of holes are in efficient working condition at different stages of the cardiac cycle.

[0057] This embodiment, through scientific size and spacing design, ensures a continuous and efficient introduction of sufficient blood under various physiological conditions (such as blood pressure fluctuations and slight vascular displacement), providing a reliable guarantee for high-flux dialysis. The uniform distribution and optimal spacing design completely eliminates local high-pressure points or blood flow stagnation areas caused by overly dense or sparse perforations, maximizing the protection of the fragile vascular endothelium and reducing the risk of vasospasm, intimal hyperplasia, and thrombosis. Simultaneously, the clear definition of key dimensions (length and spacing) provides precise standards for product design and manufacturing. This ensures that each product possesses consistently excellent performance, improving the reliability and predictability of clinical efficacy.

[0058] In a further embodiment, refer to Figures 1 to 4 The device's puncture tubing 2 has an overall tapered, tapering structure, with its outer diameter gradually decreasing from the connection point with the integrated needle hub 1 towards the distal puncture tip, with a taper ratio of 1:50 to 1:100. This tapering structure reduces puncture resistance, and the taper range has been validated by hydrodynamics, balancing puncture smoothness with the risk of vascular injury. Through this biomimetic design of "gradual thickness," the seemingly contradictory functions of the puncture needle (sharp puncture) and the indwelling catheter (soft protection) are perfectly combined. Its advantage lies in optimizing the entire puncture experience from the very first contact with the skin, aiming to achieve the dual goals of "easy operation for doctors and minimal patient discomfort," a key design detail that enhances the product's market competitiveness.

[0059] Its core principle is to optimize the two stages of the puncture process—"insertion" and "indwelling"—by applying materials mechanics and puncture physiology.

[0060] 1. The "two-stage optimization" principle of "conical / stepped tapering": Puncture stage (thicker proximal portion): The tubing at the junction with the needle hub is relatively thicker, ensuring structural strength in this area. During puncture, medical personnel need to hold the needle hub and apply force. The thicker base better resists bending and torsion, ensuring a stable and powerful puncture, allowing the needle tip to penetrate the skin and blood vessel wall along the intended path without deviation or tubing bending.

[0061] Indwelling phase (distal, finer portion): The puncture tip is designed to be extremely thin, which directly reduces the initial trauma to the tissue during puncture. At the same time, during the indwelling phase, the thin tip causes less irritation and pressure to the inner wall of the blood vessel, helping to improve patient comfort.

[0062] 2. The principle of "balancing puncture smoothness and safety" with a taper of 1:50 to 1:100: Definition of taper: Taper refers to the ratio of the change in diameter to the axial length. A 1:50 taper means that for every 50 millimeters of length, the diameter decreases by 1 millimeter; a 1:100 taper means that for every 100 millimeters of length, the diameter decreases by 1 millimeter. A 1:50 taper is more "sharp," while a 1:100 taper is more "gentle."

[0063] Puncture smoothness: An appropriate taper (e.g., 1:50) creates a sharp "cutting" edge that effectively separates tissue fibers, rather than squeezing and tearing the tissue like a blunt rod. This makes the puncture process easier and smoother, reducing the risk of puncture failure and subcutaneous hematoma.

[0064] Safety vs. Strength: If the taper is too large (i.e., too sharp, close to 1:20), while puncture is easy, the structural strength of the tip is reduced, making it prone to chipping or breaking when puncturing hard tissues (such as scars). If the taper is too small (i.e., too gentle, such as 1:150), puncture resistance increases, potentially requiring greater puncture force, increasing patient discomfort and tissue damage. The range of 1:50 to 1:100 represents a golden balance between ease of puncture and structural reliability with manageable damage.

[0065] In a further embodiment, refer to Figures 1 to 4 The device features an integrated needle hub 1 with Luer connectors 11 and 12 that communicate with the first fluid channel 21 and the second fluid channel 22, respectively. At least one pair of elastic retaining wings 13 extend outwards from both sides of the needle hub, and the surfaces of the retaining wings 13 are textured with anti-slip patterns. The Luer connectors prevent tubing from dislodging, and the elastic anti-slip retaining wings enhance the stability of the puncture grip. By introducing a highly reliable connection standard (Luer locking) and an ergonomic operating design (elastic anti-slip retaining wings), the device solves two crucial engineering problems: "how to ensure the device doesn't malfunction at critical moments" and "how to make it more stable and convenient for the operator to use." Its advantage lies in extending innovation from "inside the blood vessel" to "every touchpoint of human-machine interaction," comprehensively ensuring safety, stability, and efficiency throughout the entire process from puncture to treatment completion.

[0066] Its core principle is to ensure the stability and safety of the entire dialysis treatment process by optimizing the reliability of the connector and the operator's control.

[0067] 1. The "anti-detachment and sealing" principle of Luer Lock Connector: Beyond ordinary Luer connectors: Ordinary Luer connectors rely on friction for connection, which can easily loosen under the continuous negative or positive pressure pulsation of the dialysis machine's blood pump. Luer connectors, however, add a threaded or snap-fit ​​structure, requiring rotation or push-pull to connect / disconnect.

[0068] Ensuring zero accidents during treatment: Dialysis can last for hours, and any accidental detachment of any tubing connection can cause blood to splatter, endangering the patient's life and contaminating the medical environment. Luer connectors, through their mechanical interlocking principle, provide strong and reliable connection force, fundamentally eliminating the possibility of tubing detachment due to accidental pulling or pressure changes, ensuring a tight seal and safety throughout the entire treatment process.

[0069] 2. The "stable grip and force application" principle of elastic fixed wings: Provides additional mechanical support: During puncture, especially when a certain amount of force needs to be applied or fine-tuned, simply pinching the smooth needle hub with your fingers may not be stable enough. The stabilizing wings extending to both sides provide an ideal "pinching" or "clamping" point for the operator's thumb and forefinger, much like the grip of a pen or scalpel.

[0070] The ingenious use of "elasticity": The fixation wings are made of elastic materials (such as soft plastic or rubber coating), allowing them to adapt to different operators' hand shapes and grip habits, increasing friction and contact area to prevent slippage during the procedure. Additionally, after a successful puncture, medical staff often use tape to attach the fixation wings to the patient's skin to secure the needle hub and prevent the tubing from moving within the blood vessel. The elastic fixation wings provide a better fit to the skin and a more secure fixation.

[0071] 3. The principle of "enhanced friction" of anti-slip patterns: This involves microstructural optimization on the fixed-wing surface. By adding textures (such as meshes, twills, and grains), the static friction between the finger and the fixed-wing surface is significantly increased.

[0072] During puncture, especially when the patient is sweating or the operator is wearing gloves, the anti-slip texture ensures that the hand force is effectively transferred to the needle hub, avoiding basic errors such as "slipping and misaligning the needle," thus improving the accuracy and success rate of puncture. In a further embodiment, refer to Figures 1 to 4 The device also includes a puncture needle core 4, which is slidably inserted inside the puncture tubing 2. Its tip 41 extends beyond the distal opening of the puncture tubing 2 and can be removed from the integrated needle hub 1 after successful puncture. The cooperation between the needle core and the tubing balances puncture rigidity and indwelling flexibility, and the tip position design ensures precise puncture path. Through an ingenious "temporary skeleton" design, the soft puncture tubing is given a "steel bone," enabling it to complete the puncture task and then be removed, allowing the tubing to return to its "flesh and blood" form to protect the blood vessel. Its advantage lies in the fact that it is the cornerstone of the entire invention and perfectly reconciles the eternal contradiction between punctureability and indwelling, representing a model application of the philosophy of "combining rigidity and flexibility" in medical device design.

[0073] The principle is to use the concept of "temporary reinforcement" in composite material mechanics to solve the contradiction that a single flexible material cannot simultaneously achieve "puncture rigidity" and "retention flexibility".

[0074] 1. The contradiction and solution of "combining firmness and flexibility": Paradox: The puncture tubing 2 is made of soft TPU material, which maximizes protection of blood vessels and improves patient comfort during placement. However, if the tip of this tubing is used directly to puncture the skin and tough blood vessel walls, it will bend and deviate like a noodle, making puncture impossible. Solution: The puncture needle core 4 is a rigid metal guidewire. Before puncture, it is fully inserted into the tubing. At this point, the entire device becomes a "tubing-wrapped core," forming a temporary, high-strength composite. The flexibility of the tubing is dominated by the rigidity of the core, thus achieving sufficient puncture capability.

[0075] 2. The fluid dynamics principle of "tip alignment": This protocol specifically emphasizes that the tip of the needle stylet should extend beyond or be flush with the distal opening of the tubing. This is a crucial design detail. It avoids the "piston effect" and "tissue dragging": If the needle stylet tip is retracted inside the tubing, during puncture, the tubing tip will contact and compress the tissue before the stylet, creating folds. As the stylet continues forward, it acts like a piston, forcibly "scraping" or "dragging" this compressed tissue into the tubing lumen, causing blockage or even damage to the vessel wall. It ensures a smooth puncture path: Allowing the sharp needle stylet tip to probe first, followed closely by the tubing tip, ensures a smooth and clean puncture path, preventing the tubing from being blocked or jammed by accidentally introduced tissue. This guarantees a high success rate and establishes a pathway for smooth blood flow.

[0076] 3. The principle of "removable" temporary support: Once the puncture is successful and the tubing is in place, the needle core has fulfilled its purpose. At this point, it is a redundant and potentially problematic "foreign object." Removing it from the needle hub releases the rigid constraint on the tubing, restoring its original flexibility. This process achieves a seamless switch from "puncture mode" to "indwelling mode," perfectly combining the advantages of both materials: the "rigidity" of the steel core to accomplish difficult punctures, and the "flexibility" of the tubing to ensure comfortable indwelling.

[0077] In a further embodiment, refer to Figures 1 to 4The wall thickness of the puncture tubing 2 in the device is unevenly distributed along its length. The wall thickness is 0.1-0.2 mm at the arterial blood intake section 221 and the venous blood return section 211, and 0.2-0.3 mm in the remaining sections. The thinning of the functional sections reduces blood flow resistance, while the thickening of the remaining sections ensures structural strength. This non-uniform design requires precise calculation and verification.

[0078] Its core principle is "material mechanics optimization" based on functional zoning, that is, different material allocation and structural reinforcement are carried out in different functional areas according to their main tasks (high-speed diversion or stable transmission).

[0079] 1. The principle of "functional zoning and application according to local conditions": Arterial / venous functional segments (thin-walled: 0.1-0.2 mm) – Hemodynamic priority: Reducing blood flow resistance: According to Poiseuille's law, the resistance to fluid flow in a pipe is inversely proportional to the fourth power of the pipe radius and is related to factors such as pipe wall roughness. With a constant inner diameter of the tubing, thinning the wall can relatively "increase" the inner diameter (or, in other words, achieve a larger lumen for the same outer diameter). More importantly, a thinner wall means lower wall shear stress, resulting in less frictional resistance between the blood and the wall. This reduces resistance to blood flow and return, making blood flow smoother and reducing the risk of blood component damage (hemolysis) and intra-catheter coagulation.

[0080] Improving flow efficiency: Smoother blood flow means that a higher blood flow can be obtained under the same negative pressure, or a lower negative pressure can be used for the same blood flow requirement, which is crucial for protecting blood vessels and saving energy.

[0081] Needle seat connecting section and other sections (thickness: 0.2-0.3mm) – Structural strength is the priority: Resistance to connection stress: The areas where the tubing connects to needle hub 1 and Luer connectors (11, 12) are the most stress-concentrated areas of the entire device. This area is subjected to repeated tensile, bending, and torsional loads during connection, fixation, and the pulsating pressure generated by the dialysis machine's blood pump. Thicker tubing walls provide higher circumferential strength and bending stiffness, effectively preventing the tubing from deforming, cracking, or detaching from the connectors in these critical areas.

[0082] Ensuring structural integrity: The needle hub itself is made of rigid plastic, and the thicker wall near the end of the flexible tube can provide a more stable "transition zone," making the stress distribution at the junction of the soft and hard parts more uniform and enhancing the durability and reliability of the entire device.

[0083] 2. The principle of "local enhancement, global optimization": This design is not simply about making the tube thinner, but about using "precious materials" where they are most needed, while ensuring the overall structural safety. It doesn't pursue ultimate blood flow performance by making the entire tube extremely thin (which would make it fragile), nor does it sacrifice all performance for strength (which would impede blood flow). It embodies a systems engineering approach, finding a dynamic and optimal balance between "strength" and "performance" through precise calculations.

[0084] Using a thin-walled design in areas crucial for blood intake and return directly optimizes the device's core function—blood processing. Lower resistance and smoother blood flow translate to higher dialysis efficiency, better blood protection (reduced hemolysis and clotting), and lower energy consumption (the blood pump doesn't need excessively high negative pressure). Using a thick-walled design at the most vulnerable connection points significantly enhances the device's structural reliability. This effectively prevents serious safety incidents such as tubing rupture and connector detachment caused by routine operation, accidental pulling, or prolonged pressure pulsation, extending product lifespan and reducing medical risks. While meeting performance and safety requirements, using relatively thinner tubing walls in non-critical areas (though thicker than functional areas, but still at the minimum strength requirement) allows for precise material delivery, avoiding unnecessary material waste and helping to control the final product's manufacturing costs.

[0085] In a further embodiment, refer to Figures 1 to 4 The device features a removable protective sheath covering the proximal end of the puncture tubing 2. The sheath extends at least 5 cm beyond the puncture tip and is made of medical-grade polyethylene. The sheath's length and material ensure the tubing lumen remains clean when not in use, preventing blockage or contamination. This low-cost, high-efficiency "exoskeleton" design provides a comprehensive solution for the soft core functional component (puncture tubing) during its "dormant period," integrating sterile protection, shape fixation, and ease of use.

[0086] In a further embodiment of the present invention, referring to Figures 1 to 4 A method for performing maintenance hemodialysis using the apparatus of any of the foregoing embodiments is also provided, comprising the following steps: S1: Insert the puncture tubing 2 of the device into the vicinity of the arterial end of the arteriovenous fistula with the assistance of the puncture needle core 4, ensuring that the arterial blood return segment 221 is located in the arterial segment of the fistula and the venous blood return segment 211 is located in the venous segment of the fistula and the axial distance between the two is ≥3cm. S2: Withdraw the puncture needle core 4, leaving only the puncture tubing 2 in the fistula vessel; S3: Connect the first fluid channel 21 to the venous circuit of the dialysis machine through the first Luer connector 11, and connect the second fluid channel 22 to the arterial circuit of the dialysis machine through the second Luer connector 12; S4: Start the dialysis machine, draw arterial blood through the side hole of the arterial blood draw section 221, and after dialysis, return it to the venous end through the side hole of the venous blood return section 211 to complete the hemodialysis under a single puncture.

[0087] Its core principles are reflected in the following aspects: 1. The principle of "precise positioning and leveraging core strengths" (step S1): The first step of this method explicitly requires the operator to ensure that the axial distance L between the arterial and venous segments within the blood vessel is ≥3cm. This is not merely an operational step, but rather a "switch" that activates the aforementioned device embodiment (reduced recirculation). If the operator performs puncture arbitrarily without maintaining this distance, the core advantage of the entire device will not be realized. Therefore, this method solidifies the essence of the hardware design into a mandatory clinical action.

[0088] 2. The principle of "mode switching to achieve a balance between rigidity and flexibility" (step S2): This method clearly defines the transition points between the "puncture mode" and the "treatment mode." S1 is a "combination of rigidity and flexibility" puncture mode (soft tube + needle core), and S2 is a "purely flexible" treatment mode (soft tube only). This step is the only way to realize the value of the puncture needle core in the aforementioned embodiments. It guides the operator on when to "use leverage" and when to "let go," ensuring that the patient enjoys the comfort provided by the soft tube throughout the treatment process.

[0089] 3. The principle of "correct connection to ensure functional closed loop" (step S3): This procedure specifies that the first channel (venous return segment) must be connected to the venous circuit of the dialysis machine, and the second channel (arterial return segment) must be connected to the arterial circuit. This is a logical closed-loop verification. It ensures that the dual-chamber structure of the device is correctly matched to the functional requirements of the dialysis machine, preventing fatal medical accidents caused by incorrect connections (such as directly reinfusing arterial blood into the arterial end). At the same time, it also implicitly requires the use of the aforementioned Luer connector for reliable connection.

[0090] Instructions for use: The operator holds the device with the needle core 4 and inserts it into the blood vessel at the standard arteriovenous fistula puncture angle. The operator determines that the needle tip has entered the venous end by touch and blood color. Then, the operator slowly pushes the tubing forward, allowing the arterial drainage segment 221 and the venous return segment 211 to unfold according to the predetermined positions and spacing. After confirming the position is correct, the needle hub 1 is fixed, and the needle core 4 is removed. Finally, the Luer connectors (11, 12) are connected to the corresponding tubing of the dialysis machine, and dialysis can begin.

[0091] In summary, this invention replaces the traditional double-needle puncture with a single puncture, greatly reducing the number of punctures and pain for patients, effectively alleviating their anxiety, and significantly improving their dialysis experience and quality of life. Furthermore, the use of flexible tubing, tapered structure, and elastic fixation wings enhances the success rate of punctures, ease of operation, and overall patient comfort during dialysis.

[0092] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A double-lumen arteriovenous fistula puncture device for maintenance hemodialysis, characterized in that, include: Integrated needle hub (1); The puncture tube (2) is made of a flexible biocompatible material and has an independent first fluid channel (21) and a second fluid channel (22) inside. The front end of the first fluid channel (21) extends into a venous return segment (211), and its sidewall is provided with at least one venous return side hole (2111). The front end of the second fluid channel (22) extends into an open arterial blood-drawing segment (221), and its sidewall is provided with a plurality of blood-drawing side holes (2211) distributed axially at intervals. The axial distance L between the starting end of the arterial blood-drawing segment (221) and the front end face of the venous blood-returning segment (211) is ≥3cm; The venous return segment (211) is used to connect the venous circuit of the dialysis machine to receive blood from the venous end of the fistula, and the arterial drainage segment (221) is used to connect the arterial circuit of the dialysis machine to drain blood from the arterial end of the fistula. The sum of the total cross-sectional areas of the blood-drawing side holes (2211) is greater than the inner cross-sectional area of ​​the second fluid channel (22); The venous return segment (211) is used to connect to the venous circuit of the dialysis machine to receive blood from the venous end of the fistula; the arterial drainage segment (221) is used to connect to the arterial circuit of the dialysis machine to draw blood from the arterial end of the fistula.

2. The apparatus according to claim 1, characterized in that, The opening direction of the blood return side hole (2111) on the side wall of the venous blood return segment (211) is spatially offset from the opening direction of the blood drainage side hole (2211) on the side wall of the arterial blood drainage segment (221) to reduce the mixing of blood near the puncture point.

3. The apparatus according to claim 1, characterized in that, The number of blood-drawing side holes (2211) is 4 to 8, and the shape of each blood-drawing side hole (2211) is circular, elliptical or polygonal, and they are all oriented towards the same circumferential tangent direction or spiral distribution direction of the arterial blood-drawing segment (221).

4. The apparatus according to claim 1, characterized in that, The length of the arterial blood-drawing segment (221) is ≥2cm, and the blood-drawing side holes (2211) on its side wall are evenly distributed along the axial direction, with a spacing of 0.2-0.5cm between adjacent side holes.

5. The apparatus according to claim 1, characterized in that, The puncture tubing (2) has a tapered and tapered structure. Its outer diameter gradually decreases from the connection with the integrated needle hub (1) to the distal puncture tip, with a taper of 1:50 to 1:

100.

6. The apparatus according to claim 1, characterized in that, The integrated needle holder (1) is provided with Luer connectors (11, 12) that are respectively connected to the first fluid channel (21) and the second fluid channel (22), and at least one pair of elastic fixing wings (13) are formed by extending outward from both sides of the needle holder. The surface of the fixing wings (13) is provided with anti-slip texture.

7. The apparatus according to claim 1, characterized in that, It also includes a puncture needle core (4), which is slidably inserted inside the puncture tubing (2), with its tip extending out of the distal opening of the puncture tubing (2), and can be removed from the integrated needle hub (1) after successful puncture.

8. The apparatus according to claim 1, characterized in that, The wall thickness of the puncture tubing (2) is unevenly distributed along its length. The wall thickness at the arterial blood-drawing segment (221) and the venous blood-returning segment (211) is 0.1-0.2 mm, while the wall thickness in the remaining segments is 0.2-0.3 mm.

9. The apparatus according to claim 1, characterized in that, The proximal end of the puncture tube (2) is covered with a peelable protective sheath. The length of the protective sheath covers an area of ​​at least 5 cm on the puncture tube (2) excluding the puncture tip, and its material is medical-grade polyethylene.

10. A method for performing maintenance hemodialysis using the apparatus according to any one of claims 1-9, characterized in that, Includes the following steps: S1: Insert the puncture tube (2) of the device into the vicinity of the arterial end of the patient's arteriovenous fistula with the assistance of the puncture needle core (4), ensuring that the arterial blood return segment (221) is located in the arterial segment of the fistula, the venous blood return segment (211) is located in the venous segment of the fistula and the axial distance between the two is ≥3cm. S2: Remove the puncture needle core (4), leaving only the puncture tubing (2) in the fistula vessel; S3: Connect the first fluid channel (21) to the venous circuit of the dialysis machine through the first Luer connector (11), and connect the second fluid channel (22) to the arterial circuit of the dialysis machine through the second Luer connector (12); S4: Start the dialysis machine, draw out arterial blood through the side hole of the arterial blood draw section (221), and after dialysis treatment, return it to the venous end through the side hole of the venous blood return section (211) to complete the hemodialysis under a single puncture.

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