Indwelling intravenous needle

Abstract

This application provides an indwelling intravenous catheter, belonging to the technical field of medical devices. The indwelling intravenous catheter includes a cannula assembly and a needle core assembly. The cannula assembly includes a cannula body and a catheter connected to the cannula body. The needle core assembly includes a puncture needle, an elastic cannula, and a support component. The puncture needle is slidably inserted into the catheter, with one end extending out of the catheter to form a needle tip. The elastic cannula is fitted over the portion of the needle tip near the catheter. The support component is movably connected to the puncture needle and supports the inner side of the elastic cannula, having a supported state and a folded state. When the support component is in the supported state, at least a portion of the outer peripheral surface of the elastic cannula is a conical surface. During puncture, the elastic cannula can expand to form a conical surface under the action of the support component, making it easier for the catheter to pass through the skin and tissue under the guidance of the conical surface, reducing patient pain.

Description

Technical Field

[0001] This application belongs to the technical field of medical devices, and more specifically, relates to an indwelling intravenous catheter. Background Technology

[0002] An indwelling intravenous catheter is a medical device used for intravenous infusion. Its core consists of a flexible catheter and a stainless steel guide needle. During use, the catheter and guide needle are inserted into the blood vessel together. Once the catheter is fully inserted, the guide needle is withdrawn, leaving only the catheter in the blood vessel for subsequent infusion treatment. This design reduces vascular damage caused by repeated punctures and is particularly suitable for groups requiring continuous infusion, elderly patients, or children.

[0003] Currently, indwelling intravenous catheters have the catheter sleeved over the needle core, with the needle core extending beyond the catheter, causing the catheter tip to protrude beyond the catheter surface. This allows the needle core tip to penetrate the patient's skin and blood vessel walls. However, because the catheter diameter is slightly larger than the needle core, the puncture hole formed when the needle core penetrates the patient's skin is smaller than the outer diameter of the catheter. This makes the catheter more prone to friction and resistance when passing through the puncture hole, thus increasing the patient's pain and discomfort. Utility Model Content

[0004] The purpose of this application is to provide an indwelling intravenous catheter to solve the problem of severe pain and discomfort during the insertion of existing indwelling intravenous catheters into the patient's blood vessels.

[0005] To achieve the above objectives, this application provides an indwelling intravenous catheter, including a cannula assembly and a needle core assembly. The cannula assembly includes a cannula body and a catheter connected to the cannula body. The needle core assembly includes a puncture needle, an elastic cannula, and a support component. The puncture needle is slidably inserted into the catheter, with one end extending out of the catheter to form a needle tip. The elastic cannula is fitted over the portion of the needle tip near the catheter. The support component is movably connected to the puncture needle and supports the inner side of the elastic cannula, having a supporting state in which at least a portion of the elastic cannula is raised into a conical shape, and a folded state in which the elastic cannula is retracted into the puncture needle, causing it to contract to the outer circumferential surface of the puncture needle. When the support component is in the supporting state, at least a portion of the outer circumferential surface of the elastic cannula is a conical surface, with the larger diameter end of the conical surface facing the catheter and having the same outer diameter as the catheter. The wall thickness of the elastic cannula is 0.05–0.08 mm.

[0006] In some embodiments, the support component includes a support rod and a plurality of support plates; the support rod is slidably inserted through the inner side of the puncture needle, and the plurality of support plates are spaced apart along the circumferential direction of the puncture needle; the puncture needle is provided with a plurality of hollow portions, and the support plates are slidably embedded in a corresponding hollow portion along the radial direction of the puncture needle; when the support component is in the supported state, at least a portion of the support rod is located at the hollow portion, one end of the support plate abuts against the support rod, and the other end protrudes from the outer surface of the puncture needle and is supported on the inner side of the elastic sleeve.

[0007] In some embodiments, the support plate includes a first support portion, a second support portion, and a third support portion, which are arranged sequentially from the needle tip toward the catheter. When the support member is in a supported state, the surface of the first support portion facing away from the support rod is coplanar with the outer surface of the puncture needle, the surface of the third support portion facing away from the support rod is coplanar with the outer surface of the catheter, and the surface of the second support portion facing away from the support rod is a conical surface with a diameter that gradually increases from the first support portion toward the second support portion.

[0008] In some embodiments, the support component further includes a guide wire slidably inserted inside the puncture needle, one end of the guide wire being connected to the support rod and the other end extending to the outside of the puncture needle.

[0009] In some embodiments, the needle core assembly further includes a needle cap, and the end of the cannula body facing away from the catheter is provided with an insertion hole, the needle cap is inserted into the insertion hole, and the end of the puncture needle facing away from the needle tip is connected to the needle cap.

[0010] In some embodiments, the needle cap is provided with a needle-holding handle.

[0011] In some embodiments, the support component further includes an operating button, which is movably connected to the needle cap, and the end of the guidewire facing away from the support rod is connected to the operating button.

[0012] In some embodiments, the cannula assembly further includes an isolation plug disposed within the cannula body, through which the puncture needle is slidably inserted.

[0013] In some embodiments, the indwelling intravenous catheter further includes a connecting assembly, which includes a three-way connector, a connecting tube, a heparin cap, and a protective cap; the three-way connector has a first input end, a second input end, and an output end; one end of the connecting tube is connected to the output end, and the other end is connected to the cannula body and communicates with the interior of the cannula body; the heparin cap is movably connected to the first input end, and the protective cap is movably connected to the second input end.

[0014] In some embodiments, the connection assembly further includes a flow stop clamp movably disposed on the connection tube.

[0015] The beneficial effects of the intravenous indwelling needle provided in this application are as follows: Compared with the prior art, an elastic sleeve is provided between the needle tip and the end of the catheter. At least a portion of the elastic sleeve is supported by a supporting component to form a conical surface. During the insertion of the needle into the patient's skin, the conical portion of the elastic sleeve gradually enlarges the needle hole to the same size as the outer diameter of the catheter, thereby reducing friction and resistance when the catheter passes through the needle hole, thus alleviating the patient's discomfort and pain. Before removing the needle core, the supporting component is first retracted into the needle core, causing the elastic sleeve to contract under its own elasticity and cover the outer periphery of the needle. Due to the small thickness of the elastic sleeve, it does not obstruct the removal of the needle core, offering advantages such as simple operation and safe and reliable use. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, 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 some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of the indwelling intravenous needle in the embodiments of this application;

[0018] Figure 2 This is a partial cross-sectional view of the indwelling intravenous needle in the embodiments of this application;

[0019] Figure 3 for Figure 2 Enlarged view of section A;

[0020] Figure 4 This is an exploded view showing the connection relationship between the puncture needle, elastic cannula, and support component in an embodiment of this application.

[0021] Figure 5 This is a partial cross-sectional view of the support component in a folded state in an embodiment of this application;

[0022] Figure 6 for Figure 2 Enlarged view of section B.

[0023] The following are the labeling elements in the figure:

[0024] 100 - Tube assembly; 110 - Tube body; 120 - Guide tube; 130 - Isolation plug;

[0025] 200-Needle core assembly; 210-Punch needle; 211-Needle tip; 212-Hollowed-out section; 220-Needle cap; 2201-Retaining ring; 221-Mounting hole; 222-Through hole; 230-Needle holder; 240-Elastic sleeve; 250-Support component; 251-Support piece; 251a-First support part; 251b-Second support part; 251c-Third support part; 252-Support rod; 253-Guide wire; 254-Operating button; 2541-Limiting ring;

[0026] 300 - Connecting assembly; 310 - Connecting tube; 320 - Tee fitting; 340 - Protective cap; 330 - Heparin cap; 350 - Flow stop clamp. Detailed Implementation

[0027] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0028] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0029] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "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 application 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 application.

[0030] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0031] like Figure 1 As shown in the illustration, this application provides an indwelling intravenous needle, including a cannula assembly 100, a needle core assembly 200, and a connecting assembly 300. Both the needle core assembly 200 and the connecting assembly 300 are connected to the cannula assembly 100. The needle core assembly 200 assists the cannula assembly 100 in inserting into the patient's blood vessel and is withdrawn after a portion of the cannula assembly 100 is left in the blood vessel. The connecting assembly 300 is used to connect to an infusion device to inject medication or liquid into the cannula assembly 100 using the infusion device.

[0032] like Figure 2 As shown, the cannula assembly 100 includes a cannula body 110 and a catheter 120. The cannula body 110 is a hollow tubular structure. One end of the catheter 120 is connected to the cannula body 110 and communicates with the interior of the cannula body 110. A connecting assembly 300 is connected to the cannula body 110 and is used to inject liquid medication into the cannula body 110. The catheter 120 is inserted into the patient's blood vessel to deliver the liquid medication into the patient's blood vessel.

[0033] The needle core assembly 200 includes a puncture needle 210, a needle cap 220, and a needle holder 230. The puncture needle 210 is a slender hollow metal needle. The outer diameter of the puncture needle 210 matches the inner diameter of the catheter 120 so that it can be slidably inserted into the catheter 120. The length of the puncture needle 210 is greater than the length of the catheter 120. One end of the puncture needle 210 extends out of the catheter 120 and forms a needle tip 211, which is used to puncture the patient's skin and blood vessel wall. The end of the cannula body 110 facing away from the catheter 120 is opened to form an insertion hole. A portion of the needle cap 220 is inserted into the insertion hole. The end of the puncture needle 210 facing away from the needle tip 211 extends into the cannula body 110 and connects with the needle cap 220 so that the puncture needle 210 can be pulled out of the cannula assembly 100 by using the needle cap 220. A needle handle 230 can also be attached to the needle cap 220 to facilitate hand operation of the needle cap 220 by medical personnel.

[0034] The cannula assembly 100 also includes an isolation plug 130, which is disposed within the cannula body 110. The puncture needle 210 is slidably inserted through the isolation plug 130. The isolation plug 130 is made of elastic materials such as rubber or silicone, possessing a certain degree of elasticity and sealing. The outer diameter of the isolation plug 130 may be slightly larger than the inner diameter of the cannula body 110, allowing the isolation plug 130 to elastically contract within the cannula body 110. The puncture needle 210 penetrates the isolation plug 130, which provides support and guidance for the puncture needle 210, making it more stable during sliding and less prone to deviation or wobbling. After the puncture needle 210 is completely withdrawn from the cannula body 110, the elastic deformation of the isolation plug 130 seals the needle hole left by the puncture needle 210 in the isolation plug 130, preventing blood or other fluids from leaking out of the opening in the cannula body 110.

[0035] like Figure 1 As shown, the connecting assembly 300 includes a three-way connector 320, a connecting tube 310, a heparin cap 330, and a protective cap 340. The three-way connector 320 has a first input end, a second input end, and an output end. The cannula body 110 has a connecting end; one end of the connecting tube 310 is connected to the output end 323 of the three-way connector 320, and the other end is connected to the connecting end of the cannula body 110, communicating internally with the cannula body 110. The heparin cap 330 is movably connected to the first input end, and the protective cap 340 is movably connected to the second input end. When it is necessary to inject drugs or fluids into the patient, medical personnel can open the heparin cap 330, connect the infusion device to the first input end of the three-way connector 320, and then inject drugs or fluids into the cannula body 110 through the infusion device. The protective cap 340 is designed to seal the second input end of the tee connector 320 when it is not necessary to connect other devices to it. This prevents dust, bacteria, or other impurities from entering the tee connector 320 and the cannula body 110 through the second input end, ensuring the cleanliness and safety of the intravenous catheter. Furthermore, the connection assembly 300 includes a flow-stopping clip 350, which is movably mounted on the connecting tube 310. Medical personnel can use the flow-stopping clip 350 to control the flow of medications or fluids within the connecting tube 310 as needed.

[0036] like Figure 2 and Figure 3As shown, the needle core assembly 200 also includes an elastic sleeve 240 and a support member 250. The elastic sleeve 240 is sleeved on the portion of the needle tip 211 near the catheter 120. The support member 250 is movably connected to the puncture needle 210 and supported on the inner side of the elastic sleeve 240. It has a supported state in which at least part of the elastic sleeve 240 is supported into a conical shape, and a folded state in which it is retracted into the puncture needle 210 and retracted to the outer peripheral surface of the puncture needle 210. When the support member 250 is in the supported state, at least part of the outer peripheral surface of the elastic sleeve 240 is a conical surface, and the large-diameter end of the conical surface faces the catheter 120 and has the same outer diameter as the catheter 120.

[0037] The elastic cannula 240 is a hollow cannula made of an elastic material, such as rubber or silicone. In its natural state, the inner diameter of the elastic cannula 240 should be smaller than the outer diameter of the puncture needle 210, allowing it to expand elastically and fit over the puncture needle 210. A support member 250 is movably positioned at the location where the puncture needle 210 is covered by the elastic cannula 240. Before the puncture needle 210 pierces the patient's skin, the support member 250 partially expands the elastic cannula 240 into a conical shape, guiding the puncture needle 210 and catheter 120 into the patient's blood vessel. The thickness of the elastic cannula 240 should be less than the thickness of the catheter 120 to avoid interfering with the withdrawal of the puncture needle 210 after it contracts and covers it. Optionally, the wall thickness of the elastic cannula 240 is 0.05–0.08 mm.

[0038] In use, the indwelling intravenous catheter is first inserted into the patient's blood vessel. At this point, the needle tip 211 of the puncture needle 210 pierces the skin and blood vessel wall. Subsequently, the tapered portion of the elastic sheath 240 gradually enlarges the needle hole to the same diameter as the outer diameter of the catheter 120, allowing the catheter 120 to smoothly pass through the needle hole and enter the blood vessel, reducing resistance and friction when the catheter 120 enters the patient's blood vessel. Then, by manipulating the support component 250, it changes from a supported state to a folded state. The elastic sheath 240 contracts under its own elasticity and covers the outer periphery of the puncture needle 210. The needle cap 220 is then used to remove the puncture needle 210 from the catheter 120, leaving the catheter 120 in place in the blood vessel. Because the wall thickness of the elastic sheath 240 is small, its contraction does not obstruct the withdrawal of the puncture needle 210, thus ensuring ease of operation and safe and reliable use.

[0039] like Figure 4As shown, in some embodiments, the support member 250 includes a support rod 252 and a plurality of support plates 251; the support rod 252 is slidably inserted through the inner side of the puncture needle 210, and the plurality of support plates 251 are arranged at intervals along the circumferential direction of the puncture needle 210; the puncture needle 210 is provided with a plurality of hollow portions 212, and the support plates 251 are slidably embedded in a corresponding hollow portion 212 along the radial direction of the puncture needle 210; when the support member 250 is in a supported state, at least a portion of the support rod 252 is located at the hollow portion 212, one end of the support plate 251 abuts against the support rod 252, and the other end protrudes from the outer surface of the puncture needle 210 and is supported on the inner side of the elastic sleeve 240.

[0040] Specifically, the support rod 252 is a slender rod whose length matches the length of the hollow portion 212 on the puncture needle 210. The cross-sectional shape of the support rod 252 can be circular, square, or other suitable shapes to facilitate smooth sliding within the puncture needle 210 without damaging its internal structure. For example, the support rod 252 can be a circular rod with an outer diameter smaller than the inner diameter of the puncture needle 210. The support rod 252 can be made of metal, plastic, or other materials with sufficient strength and wear resistance to ensure good stability and durability during use.

[0041] The support piece 251 is a thin sheet structure made of metal or non-metal materials, and its shape and size are adapted to the hollow portion 212 and the elastic sleeve 240 on the puncture needle 210. The support piece 251 is embedded in the hollow portion 212 so that it can slide radially along the puncture needle 210, allowing it to protrude from the outer surface of the puncture needle 210 or retract into the interior of the puncture needle 210. The number, shape, and arrangement of the support pieces 251 can also be designed and adjusted according to different usage requirements. Optionally, there are six support pieces 251 evenly distributed around the periphery of the puncture needle 210.

[0042] When the support member 250 is in the supported state, at least a portion of the support rod 252 is located at the hollow portion 212 of the puncture needle 210, such that the end of the support piece 251 facing the inside of the puncture needle 210 is low to the surface of the support rod 252, and the end of the support piece 251 facing away from the support rod 252 protrudes from the outer surface of the puncture needle 210, so as to support the elastic sleeve 240 by using the side of the support piece 251 facing away from the support rod 252.

[0043] At least a portion of the surface of the support piece 251 should be tapered to support the corresponding portion of the elastic sleeve 240 as a tapered surface. Figure 4As shown, in some embodiments, the support piece 251 includes a first support portion 251a, a second support portion 251b, and a third support portion 251c. The first support portion 251a, the second support portion 251b, and the third support portion 251c are arranged sequentially from the needle tip portion 211 toward the catheter 120. When the support member 250 is in a supported state, the surface of the first support portion 251a facing away from the support rod 252 is coplanar with the outer surface of the puncture needle 210, the surface of the third support portion 251c facing away from the support rod 252 is coplanar with the outer surface of the catheter 120, and the surface of the second support portion 251b facing away from the support rod 252 is a conical surface with a diameter that gradually increases from the first support portion 251a toward the second support portion 251b.

[0044] When the support component 250 is in the supported state, the first support portion 251a lifts the corresponding part of the elastic sheath 240 and aligns it with the outer surface of the puncture needle 210, ensuring that a portion of the lifted elastic sheath 240 can cover the puncture needle 210, thereby maintaining the position and shape of the elastic sheath 240 on the puncture needle 210. The second support portion 251b lifts the corresponding part of the elastic sheath 240 into a tapered surface, so that the large-diameter end of the tapered surface of the elastic sheath 240 matches the outer diameter of the catheter 120. The third support portion 251c lifts the corresponding part of the elastic sheath 240 and aligns it with the outer surface of the catheter 120, providing a smooth transition for the catheter 120 to smoothly enter the blood vessel.

[0045] like Figure 5 As shown, after the puncture needle 210 and catheter 120 have entered the patient's blood vessel, before withdrawing the puncture needle 210, the support rod 252 is slid towards the needle cap 220, causing the support rod 252 to disengage from the perforated part 212. Under the elastic action of the elastic sleeve 240, the support piece 251 retracts inward towards the puncture needle 210. At this time, the support component 250 changes from a supporting state to a folded state. After losing the support of the support piece 251, the elastic sleeve 240 retracts and tightly covers the outer circumference of the puncture needle 210. Subsequently, medical personnel can smoothly withdraw the puncture needle 210 from the catheter 120 through the needle cap 220. Because of its small wall thickness, the elastic sleeve 240 does not obstruct the withdrawal of the puncture needle 210, ensuring ease of operation and safe and reliable use.

[0046] In some embodiments, the support member 250 further includes a guide wire 253, which is slidably inserted into the puncture needle 210. One end of the guide wire 253 is connected to the support rod 252, and the other end extends to the outside of the puncture needle 210.

[0047] Specifically, the guidewire 253 can be made of metal, plastic, or other materials with sufficient strength and flexibility. The diameter of the guidewire 253 should be smaller than the inner diameter of the puncture needle 210 so that it can be inserted inside the puncture needle 210. The length of the guidewire 253 is adapted to the puncture needle 210. One end of the guidewire 253 is connected to the support rod 252, and the other end extends to the outside of the puncture needle 210, so that medical personnel can use the guidewire 253 to pull the support rod 252 to move inside the puncture needle 210, so that the support plate 251 changes from a supported state to a folded state.

[0048] like Figure 6 As shown, in some embodiments, the support member 250 further includes an operation button 254, which is movably connected to the needle cap 220, and the end of the guide wire 253 facing away from the support rod 252 is connected to the operation button 254.

[0049] Specifically, the operating button 254 can be a rod-shaped structure with a circular cross-section. The operating button 254 is slidably connected to the side of the needle cap 220 facing away from the sleeve body 110. For example, the side of the needle cap 220 facing away from the sleeve body 110 has a mounting hole 221. The diameter of the operating button 254 is smaller than the inner diameter of the mounting hole 221, and a limiting ring 2541 is provided on the operating button 254. The limiting ring 2541 is slidably embedded in the mounting hole 221 so that the operating button 254 can slide along the axial direction of the needle cap 220. A fixing ring 2201 is provided on the end face of the needle cap 220 facing away from the sleeve body 110. The fixing ring 2201 blocks the opening of the mounting hole 221 to prevent the limiting ring 2541 from coming out of the mounting hole 221. The needle cap 220 may also have a through hole 222, which connects the mounting hole 221 and the sleeve body 110. One end of the guide wire 253 facing away from the support rod 252 is inserted into the through hole 222 and connected to the operating button 254 so that the guide wire 253 can be moved by pulling the operating button 254.

[0050] The length of the mounting hole 221 can be matched with the length of the support rod 252, so that the movement distance of the support rod 252 can be controlled by the movement of the limiting ring 2541 within the mounting hole 221. During operation, medical staff only need to pull the operating button 254 outward to the limit position to completely detach the surface support rod 252 from the multiple support pieces 251, improving the convenience and accuracy of operation. In addition, the surface of the operating button 254 can also be provided with anti-slip textures or raised structures to increase the friction and stability when medical staff hold it, preventing slippage or detachment during operation, ensuring the safety and reliability of operation, and providing patients with a better user experience.

[0051] In summary, the intravenous indwelling needle provided in this application, by being equipped with an elastic cannula 240 and a support component 250, can reduce the patient's pain and discomfort during the insertion into the patient's blood vessels. At the same time, it is easy to operate, safe and reliable to use, and has broad application prospects.

[0052] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An indwelling intravenous needle, characterized in that, The device includes a cannula assembly and a needle core assembly. The cannula assembly includes a cannula body and a catheter connected to the cannula body. The needle core assembly includes a puncture needle, an elastic cannula, and a support component. The puncture needle is slidably inserted into the catheter, with one end extending out of the catheter to form a needle tip. The elastic cannula is fitted over the portion of the needle tip near the catheter. The support component is movably connected to the puncture needle and supports the inner side of the elastic cannula. It has a supporting state in which at least a portion of the elastic cannula is raised into a conical shape, and a folded state in which the elastic cannula is retracted into the puncture needle, causing it to contract to the outer circumferential surface of the puncture needle. When the support component is in the supporting state, at least a portion of the outer circumferential surface of the elastic cannula is a conical surface, with the larger diameter end of the conical surface facing the catheter and having the same outer diameter as the catheter. The wall thickness of the elastic cannula is 0.05–0.08 mm.

2. The indwelling intravenous needle according to claim 1, characterized in that, The support component includes a support rod and multiple support plates; the support rod is slidably inserted through the inner side of the puncture needle, and the multiple support plates are spaced apart along the circumferential direction of the puncture needle; the puncture needle is provided with multiple hollow portions, and the support plates are slidably embedded in a corresponding hollow portion along the radial direction of the puncture needle; when the support component is in the supported state, at least a portion of the support rod is located at the hollow portion, one end of the support plate abuts against the support rod, and the other end protrudes from the outer surface of the puncture needle and is supported on the inner side of the elastic sleeve.

3. The indwelling intravenous needle according to claim 2, characterized in that, The support plate includes a first support portion, a second support portion, and a third support portion, which are arranged sequentially from the needle tip toward the catheter. When the support component is in a supported state, the surface of the first support portion facing away from the support rod is coplanar with the outer surface of the puncture needle, the surface of the third support portion facing away from the support rod is coplanar with the outer surface of the catheter, and the surface of the second support portion facing away from the support rod is a conical surface with a diameter that gradually increases from the first support portion toward the second support portion.

4. The indwelling intravenous needle according to claim 2, characterized in that, The support component also includes a guide wire, which is slidably inserted inside the puncture needle. One end of the guide wire is connected to the support rod, and the other end extends to the outside of the puncture needle.

5. The indwelling intravenous needle according to claim 4, characterized in that, The needle core assembly also includes a needle cap. The end of the cannula body facing away from the catheter is provided with an insertion hole. The needle cap is inserted into the insertion hole. The end of the puncture needle facing away from the needle tip is connected to the needle cap.

6. The indwelling intravenous needle according to claim 5, characterized in that, The needle cap is provided with a needle-holding handle.

7. The indwelling intravenous needle according to claim 5, characterized in that, The support component also includes an operating button, which is movably connected to the needle cap, and the end of the guidewire facing away from the support rod is connected to the operating button.

8. The indwelling intravenous needle according to claim 1, characterized in that, The cannula assembly further includes an isolation plug disposed within the cannula body, and the puncture needle is slidably inserted through the isolation plug.

9. The indwelling intravenous needle according to any one of claims 1-8, characterized in that, The indwelling intravenous catheter also includes a connecting assembly, which includes a three-way connector, a connecting tube, a heparin cap, and a protective cap. The three-way connector has a first input end, a second input end, and an output end. One end of the connecting tube is connected to the output end, and the other end is connected to the cannula body and communicates with the interior of the cannula body. The heparin cap is movably connected to the first input end, and the protective cap is movably connected to the second input end.

10. The indwelling intravenous needle according to claim 9, characterized in that, The connecting assembly also includes a flow stop clamp, which is movably disposed on the connecting pipe.

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