Dual lumen cannula

Abstract

A dual lumen cannula, comprising a drainage tube (100) and a return tube (200). The drainage tube (100) has a drainage lumen (101). The return tube (200) passes through the drainage tube (100), and comprises a first return tube section (201) exposed at the distal end of the drainage tube (100), a second return tube section (202) built in the drainage lumen (101), and a third return tube section (203) exposed at the proximal end of the drainage tube (100). The first return tube section (201) is sealedly connected to the drainage tube (100); the proximal end of the second return tube section (202) is sealedly connected to the third return tube section (203); a fixed part (204) and a free part (205) are arranged in the circumferential direction of the distal end of the second return tube section (202); the fixed part (204) is connected to the first return tube section (201); and the free part (205) has a first state of being attached to the inner wall of the first return tube section (201) and a second state of being spaced apart from the inner wall of the first return tube section (201). Both the drainage tube (100) and the return tube (200) have sufficient flow cross-sectional area, such that the drainage and return effect can be guaranteed.

Description

Double-lumen cannula Technical Field

[0001] The present invention relates to the field of medical devices, in particular to a double-lumen cannula. Background Art

[0002] Cannulas are key components of the extracorporeal membrane oxygenation (ECMO) system, connecting directly to the body's blood vessels. They serve as a bridge between the ECMO circuit and the body's blood vessels, and are crucial for the proper function of the ECMO system. An ECMO system contains two cannulas: one for withdrawing venous blood and one for returning arterial blood, oxygenated by the ECMO system, to the body's blood vessels. Vein-to-vein cannulation (VV-ECMO) is a common ECMO cannulation method for patients with pulmonary failure. Typically, a single-lumen cannula is inserted through a femoral vein puncture into the inferior vena cava near the right atrium. Venous blood is withdrawn from the inferior vena cava, oxygenated by the ECMO system, and then another single-lumen cannula is inserted through the internal jugular vein into the superior vena cava to return the oxygenated arterial blood to the body. Existing VV-ECMO requires two cannulas, requiring two separate cannulations through two surface punctures. This procedure is complex and increases the risk of infection.

[0003] One solution is to use a double-lumen cannula, inserting the return line into the drainage line, integrating the drainage line for venous blood and the return line for arterial blood into one. This allows only a single cannula, reduces surgical complexity, and minimizes trauma to the body surface and blood vessels. However, with a double-lumen cannula, the drainage line and the return line occupy the same vascular path, limiting the cross-sectional area of ​​the line. This makes it difficult to ensure sufficient flow cross-sectional area for both the drainage line and the return line, and thus cannot guarantee effective drainage and return flow.

[0004] Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a double-lumen cannula so that both the drainage pipeline and the return pipeline have sufficient flow cross-sectional area to ensure the drainage and return effect.

[0006] The present disclosure provides a double-lumen cannula, comprising:

[0007] a drainage tube having a drainage lumen;

[0008] A return tube passes through the drainage tube, comprising a first return tube segment exposed at the distal end of the drainage tube, a second return tube segment built into the drainage cavity, and a third return tube segment exposed at the proximal end of the drainage tube.

[0009] The first reflux pipe segment is sealed and connected to the drainage pipe, the proximal end of the second reflux pipe segment is sealed and connected to the third reflux pipe segment, and the distal end of the second reflux pipe segment has a fixed portion and a free portion in the circumferential direction, the fixed portion is connected to the first reflux pipe segment, and the free portion has a first state of being in contact with the inner wall of the second reflux pipe segment and a second state of being separated from the inner wall of the second reflux pipe segment.

[0010] Optionally, the fixing portion occupies less than 1 / 2 of the circumference of the distal end of the second return pipe segment;

[0011] The free portion occupies more than 1 / 2 of the circumference of the distal end of the second return pipe segment.

[0012] Optionally, a drainage joint is provided at the proximal end of the drainage tube, and a reflux joint is provided on the third reflux tube section.

[0013] Optionally, the second return pipe section is a thin-walled deformable flexible tube; the wall thickness of the second return pipe section is smaller than the wall thickness of the first return pipe section; the wall thickness of the second return pipe section is smaller than the wall thickness of the drainage pipe.

[0014] Optionally, there is a gap between the outer wall of the second return pipe section and the inner wall of the drainage pipe;

[0015] A drainage hole is provided on the side wall of the distal end of the drainage tube, and a reflux hole is provided on the side wall of the distal end of the first reflux tube section; after the intubation is completed, the drainage hole is located in the inferior vena cava, superior vena cava or right atrium.

[0016] Optionally, a first through hole is provided at the distal end of the drainage tube, and the first reflux pipe section passes through the first through hole and is sealedly connected to the hole wall of the first through hole.

[0017] Optionally, the outer diameter of the first return pipe section is smaller than the outer diameter of the drainage pipe;

[0018] The outer wall of the first reflux pipe section transitions smoothly to the outer wall of the drainage pipe.

[0019] Optionally, the first return pipe section and the drainage pipe are integrally formed.

[0020] Optionally, a second through hole is provided on the side wall of the proximal end of the drainage tube, the reflux tube passes through the second through hole and extends toward the distal end of the drainage tube, and the drainage tube is sealedly connected to the hole wall of the second through hole.

[0021] Optionally, the angle between the second return pipe section and the third return pipe section is greater than 90°.

[0022] Optionally, the second return pipe section and the third return pipe section are integrally formed.

[0023] Optionally, a first support body is provided in the wall of the first reflux pipe section; the first support body is used to prop up the wall of the first reflux pipe section and make the first reflux pipe section bendable;

[0024] The density of the first support body on the side of the first return pipe section away from the drainage pipe is lower than the density of the first support body on the side close to the drainage pipe, and the flexibility of the side of the first return pipe section away from the drainage pipe is greater than the flexibility of the side close to the drainage pipe.

[0025] Optionally, the length of the reflux tube is greater than that of the drainage tube. After the intubation is completed, the reflux hole on the reflux tube is located in the left atrium, and the drainage hole of the drainage tube is located in the right atrium.

[0026] The implementation of the above scheme has the following beneficial effects:

[0027] The double-lumen cannula provided by the present invention has both a drainage tube and a return tube, which are integrated into a single tube. When used, only one puncture hole needs to be formed on the body surface, and the risk of bleeding and infection is significantly reduced compared to the conventional method of forming two puncture holes on the body surface.

[0028] On the return tube, the second return tube section is partially connected to the first return tube section. When the tube is placed, the guide core is inserted into the drainage tube and the first return tube section, squeezing the second return tube section to one side. Since the guide core does not need to pass through the second return tube section, the second return tube section does not need to adapt to the guide core size. Its diameter and wall thickness can be made smaller, reducing the cross-sectional area occupied by the drainage cavity, making the flow cross-sectional area between the inner wall of the drainage tube and the outer wall of the second return tube section larger. Because the blood pressure of the arterial blood returned through the return tube is greater than the blood pressure of the venous fluid drained through the drainage tube, even if the diameter of the second return tube section is made smaller, it will not hinder the return of arterial blood. Under the condition that the cross-sectional area of ​​the drainage cavity is constant, the present invention expands the flow area of ​​venous blood drainage by reducing the cross-sectional area of ​​the return tube in the drainage cavity, so that both the drainage tube and the return tube have sufficient flow cross-sectional area, ensuring the drainage and reflux effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG1 is a front view of a double-lumen cannula provided in an embodiment of the present application;

[0030] FIG2 is a right side view of a double-lumen cannula provided in an embodiment of the present application;

[0031] FIG3 is a cross-sectional view of a double-lumen cannula provided in an embodiment of the present application;

[0032] FIG4 is a schematic diagram of a partial structure of the structure shown in FIG3 ;

[0033] FIG5 is a schematic diagram of a partial structure of the structure shown in FIG3 ;

[0034] FIG6 is an enlarged view of portion A in FIG5 ;

[0035] FIG7 is a cross-sectional view of a guide core provided in an embodiment of the present application when placed into a double-lumen cannula;

[0036] FIG8 is a cross-sectional view of a double-lumen cannula after the guide core is removed from the double-lumen cannula provided in an embodiment of the present application;

[0037] FIG9 is a schematic structural diagram of the guide core provided in an embodiment of the present application.

[0038] In the figure: 100 drainage tube, 101 drainage cavity, 102 drainage connector, 103 gap, 104 drainage hole, 105 first through hole, 106 second through hole, 107 second support body, 108 drainage tube transition section, 200 return pipe, 201 first return pipe segment, 202 second return pipe segment, 203 third return pipe segment, 204 fixed portion, 205 free portion, 206 return connector, 207 return hole, 208 first support body, 209 return pipe head end, 210 avoidance channel, 211 flow channel, 300 guide core, 301 guide core through hole, 302 first guide core segment, 303 second guide core segment, 304 third guide core segment, 305 fourth guide core segment, 306 first clamping portion, 307 second clamping portion, 308 docking channel; 400 guide wire. DETAILED DESCRIPTION

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0040] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0041] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0042] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0043] In the description of the present invention, it should be noted that, unless otherwise specified or limited, the terms "disposed" and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0044] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0045] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0046] This embodiment provides a double-lumen cannula, as shown in Figures 1-8. The double-lumen cannula includes a drainage tube 100 and a return tube 200. The drainage tube 100 has a drainage lumen 101 therein. The return tube 200 passes through the drainage tube 100. The return tube 200 includes a first return tube segment 201, a second return tube segment 202, and a third return tube segment 203. The first return tube segment 201 is exposed at the distal end of the drainage tube 100, and the third return tube segment 203 is exposed at the proximal end of the drainage tube 100. The second return tube segment 202 is embedded in the drainage lumen 101, and the two ends of the second return tube segment 202 are respectively connected to the third return tube segment 203 and the first return tube segment 201. The length of the return tube 200 is greater than that of the drainage tube 100. A drainage connector 102 is provided at the proximal end of the drainage tube 100, and a return connector 206 is provided on the third return tube segment 203. Referring to Figures 4 and 5 , drainage tube 100 is provided with a drainage hole 104 on its distal sidewall, and first return tube segment 201 is provided with a return hole 207 on its distal sidewall. A gap 103 is provided between the outer wall of second return tube segment 202 and the inner wall of drainage tube 100, allowing venous blood entering through drainage hole 104 to flow through this gap 103 toward drainage connector 102.

[0047] It should be noted that the drainage hole 104 on the double-lumen cannula is used to drain venous blood from the body, and the return hole 207 is used to return oxygen-rich arterial blood to the body. The positions of the drainage hole 104 and the return hole 207 can be designed according to the specific use site and body size. For example, according to the distance between the predetermined position of venous blood and the predetermined position of returned arterial blood, the distance between the drainage hole 104 and the return hole 207 can be changed to ensure that the drainage hole 104 and the return hole 207 can be accurately delivered to the designated position.

[0048] It should be noted that the drainage hole 104 of the double-lumen cannula is located in the inferior vena cava, superior vena cava, or right atrium, and is used to draw venous blood into the drainage cavity 101 of the double-lumen cannula and lead it to the body. The blood is then oxygenated and treated by an oxygenator to remove carbon dioxide to become oxygen-rich arterial blood. Finally, the blood is directly perfused into the left atrium by a centrifugal pump through the return connector 206, the third return pipe segment 203, the second return pipe segment 202, and the first return pipe segment 201 in sequence, thereby reducing the burden on the heart and lungs and providing cardiopulmonary support. For example, after the cannula is intubated, the return hole 207 on the return pipe 200 is located in the left atrium, and the drainage hole 104 of the drainage pipe 100 is located in the right atrium.

[0049] The first return pipe segment 201 is sealedly connected to the drainage tube 100, and the proximal end of the second return pipe segment 202 is sealedly connected to the third return pipe segment 203. The distal end of the second return pipe segment 202 has a fixed portion 204 and a free portion 205 circumferentially. The fixed portion 204 is connected to the first return pipe segment 201, and the free portion 205 has a first state in which it adheres to the inner wall of the second return pipe segment 202 and a second state in which it is separated from the inner wall of the second return pipe segment 202. When the free portion 205 is in the first state, the first return pipe segment 201, the second return pipe segment 202, and the third return pipe segment 203 are sequentially connected to form a flow channel 211 for draining arterial blood, as shown in Figure 8. When the free portion is in the second state, an escape channel 210 is formed between the outer wall of the second return pipe segment 202 and the inner wall of the first return pipe segment 201, allowing the guide core 300 used for placing a double-lumen cannula to pass through, as shown in Figure 7.

[0050] Specifically, the fixed portion 204 occupies less than 1 / 2 of the circumference of the distal end of the second return pipe segment 202, while the free portion 205 occupies more than 1 / 2 of the circumference of the distal end of the second return pipe segment 202. This ensures that after the free portion 205 is deformed, a sufficiently large channel exists between the outer wall of the second return pipe segment 202 and the inner wall of the first return pipe segment 201 for the guide core 300 to pass through. In one possible implementation, the fixed portion 204 occupies 1 / 3 of the circumference of the distal end of the second return pipe segment 202, while the free portion 205 occupies 2 / 3 of the circumference of the distal end of the second return pipe segment 202. The fixed portion 204 is bonded to the inner wall of the second return pipe segment 202.

[0051] The second return pipe section 202 is a thin-walled, deformable, flexible tube. The free portion 205 of the second return pipe section 202 is able to move closer to the fixed portion 204 after being squeezed by the guide core 300. The wall thickness of the second return pipe section 202 is smaller than that of the first return pipe section 201; the wall thickness of the second return pipe section 202 is smaller than that of the drainage tube 100. A first support body 208 is provided within the wall of the first return pipe section 201. The first support body 208 is used to prop open the wall of the first return pipe section 201 and allow the first return pipe section 201 to bend. A second support body 107 is provided within the wall of the drainage tube 100. The second support body 107 is used to prop open the wall of the drainage tube 100 and allow the drainage tube 100 to bend. The first support body 208 and the second support body 107 can be support bodies with a spiral structure or a mesh structure, such as a support spring.

[0052] The first return pipe segment 201 and the drainage tube 100 are to be placed in the body. The first return pipe segment 201 and the drainage tube 100 have a certain degree of support strength and flexibility, and can reach the predetermined position along the complete vascular conduit. The second return pipe segment 202 is embedded in the drainage cavity 101 and does not need to directly contact the blood vessel wall. In this embodiment, no support body is provided in the second return pipe segment 202. When the cross-sectional flow area remains the same, the wall of the second return pipe segment 202 can be made thinner, reducing the cross-sectional area of ​​the return pipe 200 in the drainage cavity 101 and expanding the flow area of ​​venous blood drainage.

[0053] In one possible implementation, the density of the first supports 208 on the side of the first return pipe segment 201 away from the drainage pipe 100 is lower than the density of the first supports 208 on the side closer to the drainage pipe 100. The side of the first return pipe segment 201 away from the drainage pipe 100 is more flexible than the side closer to the drainage pipe 100. In this embodiment, the density of the second supports 107 at different locations on the second return pipe segment 202 is adjusted to achieve different bending strengths at different locations on the second return pipe segment 202. A denser distribution of the second supports 107 results in a greater bending strength. Taking the second support body 107 as an example, relatively sparse springs are set on the second return pipe segment 202 away from the drainage tube 100, and relatively dense springs are set on the second return pipe segment 202 close to the drainage tube 100. Then, the bending strength of the second return pipe segment 202 close to the drainage tube 100 is greater than the bending strength of the second return pipe segment 202 away from the drainage tube 100. In this way, the distal end of the second return pipe segment 202 can be made more flexible, reducing the difficulty of placing the distal end of the second return pipe segment 202 through the tricuspid valve and the pulmonary valve.

[0054] Please refer to Figure 3. The outer diameter of the first return tube segment 201 is smaller than the outer diameter of the drainage tube 100. On the one hand, the first return tube segment 201 serves as the head end of the entire double-lumen cannula. Reducing the outer diameter of the first return tube segment 201 is conducive to its smooth passage in the blood vessel. At the same time, since the first return tube segment 201 is used to transport arterial blood, the pressure of arterial blood is relatively high during transportation. Even if its outer diameter and inner diameter are reduced, the arterial blood can still flow smoothly in the first return tube segment 201; on the other hand, reducing the outer diameter of the first return tube segment 201 can also reduce the trauma to tissues such as the blood vessel wall and heart valves during the insertion process.

[0055] The outer wall of the first reflux tube section 201 transitions smoothly with the outer wall of the drainage tube 100 , and there is no step surface at the distal junction of the reflux tube 200 and the drainage tube 100 , so that the vessel wall will not be damaged when the cannula is inserted into the blood vessel.

[0056] In one possible implementation, the distal end of the drainage tube 100 is provided with a first through hole 105, and the first return pipe section 201 passes through the first through hole 105 and is sealed to the wall of the first through hole 105. In another possible implementation, the first return pipe section 201 and the drainage tube 100 are integrally formed.

[0057] Please refer to Figure 3. A second through hole 106 is also provided on the side wall of the proximal end of the drainage tube 100. The return pipe 200 extends through the second through hole 106 to the distal end of the drainage tube 100, and the drainage tube 100 is sealed and connected to the hole wall of the second through hole 106. The angle between the second return pipe section 202 and the third return pipe section 203 is greater than 90°. In this embodiment, the return pipe 200 is tilted at a certain angle to penetrate the drainage cavity 101 to prevent the blood from rapidly turning in the return pipe 200 and causing damage to blood cells. Among them, the second return pipe section 202 and the third return pipe section 203 are integrally formed. Of course, the second return pipe section 202 and the third return pipe section 203 can also be separately formed and then sealed and connected.

[0058] The double-lumen cannula provided by the present invention has both a drainage tube 100 and a return tube 200. The drainage tube 100 and the return tube 200 are integrated into a single tube. When used, only one puncture hole needs to be formed on the body surface. The risk of bleeding infection is significantly reduced compared to the conventional method of forming two puncture holes on the body surface.

[0059] On the return pipe 200, the second return pipe section 202 is partially connected to the first return pipe section 201. When the tube is placed, the guide core 300 passes through the drainage tube 100 and the first return pipe section 201, squeezing the second return pipe section 202 to one side. Since the guide core 300 does not need to pass through the second return pipe section 202, the second return pipe section 202 does not need to adapt to the size of the guide core 300. Its tube diameter and wall thickness can be made smaller, reducing the cross-sectional area occupied by the drainage cavity 101, so that the flow cross-sectional area between the inner wall of the drainage tube 100 and the outer wall of the second return pipe section 202 is larger. Because the blood pressure of the arterial blood returned through the return tube 200 is greater than the blood pressure of the venous fluid drained through the drainage tube 100, even if the diameter of the second return tube section 202 is reduced, it will not hinder the return of arterial blood. Under the condition that the cross-sectional area of ​​the drainage cavity 101 is constant, the present invention expands the flow area of ​​venous blood drainage by reducing the cross-sectional area of ​​the return tube 200 in the drainage cavity 101, so that both the drainage tube 100 and the return tube 200 have sufficient flow cross-sectional area to ensure the drainage and reflux effect.

[0060] The double-lumen catheter provided in this embodiment is inserted into the body using a guide core. Referring to Figure 9, the guide core 300 has a guide core through hole 301 running through both ends of the guide core 300. The guide core through hole 301 is used to pass a guide wire 400. The guide core through hole 301 includes a docking channel 308, and the diameter of the docking channel 308 matches the diameter of the guide wire 400. Optionally, the diameter of the docking channel 308 is slightly larger than the diameter of the guide wire 400, or the diameter of the docking channel 308 is equal to the diameter of the guide wire 400. The outer wall of the guide core 300 has a clamping portion. When the guide core 300 is inserted into the double-lumen cannula, the clamping portion fits with the inner wall of the drainage cavity 101 and / or the inner wall of the first reflux pipe section 201.

[0061] In one possible implementation, the core guide 300 includes a first core guide segment 302, a second core guide segment 303, a third core guide segment 304, and a fourth core guide segment 305, which are sequentially connected. The core guide through hole 301 passes through the first core guide segment 302, the second core guide segment 303, the third core guide segment 304, and the fourth core guide segment 305. The outer diameter of the fourth core guide segment 305 is larger than the outer diameter of the second core guide segment 303. The outer diameter of the third core guide segment 304 gradually decreases from the side close to the fourth core guide segment 305 to the side close to the second core guide segment 303. The outer diameter of the first core guide segment 302 gradually decreases from the side close to the second core guide segment 303 to the side away from the second core guide segment 303. The docking channel 308 is provided in the first core guide segment. The clamping portion includes a first clamping portion 306 and a second clamping portion 307. The first clamping portion 306 is provided on the first core guide segment 302, and the second clamping portion 307 is provided on the third core guide segment 304. For example, the first clamping portion 306 may be located at a position on the first core guide segment 302 connected to the second core guide segment 303, and the second clamping portion 307 may be located at a position on the third core guide segment 304 connected to the fourth core guide segment 305.

[0062] In one possible implementation, the drainage pipe includes a drainage pipe transition section 108, which is connected to the first return pipe section 201. Both the outer diameter and the inner diameter of the drainage pipe transition section 108 gradually decrease from a side away from the first return pipe section 201 to a side closer to the first return pipe section 201. Referring to Figures 3 and 4 , a return pipe head end 209 is provided on a side of the first return pipe section 201 away from the second return pipe section 202. The inner diameter of the return pipe head end 209 gradually decreases from a side closer to the second return pipe section 202 to a side away from the second return pipe section 202. When the core guide 300 is inserted into the double-lumen cannula, the first core guide segment 302 partially extends out of the first return tube segment 201, the first clamping portion 306 abuts the inner wall of the return tube head, and the second clamping portion 307 abuts the inner wall of the drainage tube transition section, thereby positioning the core guide 300 within the double-lumen cannula. It is important to note that the contact surface between the core guide 300 and the double-lumen cannula should not be too large. If the contact surface is too large, the friction between the double-lumen cannula and the core guide 300 will increase, making it difficult to remove the core guide 300.

[0063] The insertion process of the cannula in this embodiment includes:

[0064] 1. Pass the core guide 300 through the drainage connector 102, the drainage cavity 101, and the first return pipe segment 201 in sequence. At this time, the core guide 300 squeezes the second return pipe segment 303 to one side. The front end of the first core guide segment 302 of the core guide 300 passes through the first return pipe segment 201. The first clamping portion 306 at the rear end of the first core guide segment 302 fits against the inner wall of the return pipe head end 209 on the first return pipe segment 201. The second clamping portion 307 on the third core guide segment 304 fits against the inner wall of the drainage pipe transition segment 108. The first guide core segment 302 is at the head end of the guide core 300, and the fourth guide core segment 305 is at the tail end of the guide core 300. When the guide core 300 moves along the direction indicated by the head end, the guide core 300 is always sleeved in the double-lumen cannula and can drive the double-lumen cannula to move. When the guide core 300 moves along the direction indicated by the tail end, the guide core 300 can exit the double-lumen cannula.

[0065] 2. The head end of the guide wire 400 is sent through the puncture hole on the body surface along the blood vessel to the designated position (such as the left atrium), and the tail end of the guide wire 400 is exposed outside the body surface.

[0066] 3. Pass the tail end of the guide wire 400 through the first guide core segment 302, the second guide core segment 303, the third guide core segment 304 and the fourth guide core segment 305 of the guide core 300 in sequence. The outer wall of the guide wire 400 is fitted with the inner wall of the docking channel 308. The front end of the guide wire 400 extends out of the first guide core segment 302, and the tail end of the guide wire 400 extends out of the fourth guide core segment 305.

[0067] 4. Use the guide wire 400 to guide the guide core 300 and the double-lumen cannula into the blood vessel until the reflux hole 207 and the drainage hole 104 of the double-lumen cannula reach the designated position, and then withdraw the guide wire 400 and the guide core 300 from the double-lumen cannula to complete the placement of the double-lumen cannula.

[0068] When using a double-lumen cannula to divert blood, since the blood pressure of the arterial blood returned to the body from the return tube 200 is much greater than the blood pressure of the venous blood flowing out of the drainage tube 100, the second return tube segment 303 can stretch under the impact of the arterial blood, so that the outer wall of the second return tube 303 is tightly attached to the inner wall of the first return tube segment 201, forming an arterial blood flow channel 211, ensuring that the arterial blood flows smoothly out of the return hole 207.

[0069] Note that the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will appreciate that the present invention is not limited to the specific embodiments herein, and that various obvious changes, readjustments, and substitutions are possible for those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the scope of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A double-lumen cannula, characterized in that: include: A drainage tube (100) having a drainage cavity (101); A return tube (200) passes through the drainage tube (100), comprising a first return tube section (201) exposed at the distal end of the drainage tube (100), a second return tube section (202) built into the drainage cavity (101), and a third return tube section (203) exposed at the proximal end of the drainage tube (100); The first return pipe section (201) is sealedly connected to the drainage pipe (100), the proximal end of the second return pipe section (202) is sealedly connected to the third return pipe section (203), and the distal end of the second return pipe section (202) has a fixed portion (204) and a free portion (205) in the circumferential direction, the fixed portion (204) is connected to the first return pipe section (201), and the free portion (205) has a first state of being in contact with the inner wall of the second return pipe section (202) and a second state of being spaced away from the inner wall of the second return pipe section (202).

2. The double-lumen cannula according to claim 1, characterized in that: The fixing portion (204) occupies less than 1 / 2 of the circumference of the distal end of the second return pipe section (202); The free portion (205) accounts for more than 1 / 2 of the circumference of the distal end of the second return pipe section (202).

3. The double-lumen cannula according to claim 1, characterized in that: The proximal end of the drainage tube (100) is provided with a drainage joint (102), and the third reflux pipe section (203) is provided with a reflux joint (206).

4. The double-lumen cannula according to claim 1, characterized in that: The second return pipe section (202) is a thin-walled deformable flexible pipe; the wall thickness of the second return pipe section (202) is smaller than the wall thickness of the first return pipe section (201); the wall thickness of the second return pipe section (202) is smaller than the wall thickness of the drainage pipe (100).

5. The double-lumen cannula according to claim 1, characterized in that: There is a gap between the outer wall of the second reflux pipe section (202) and the inner wall of the drainage pipe (100) (103)； A drainage hole (104) is provided on the side wall at the distal end of the drainage tube (100), and a reflux hole (207) is provided on the side wall at the distal end of the first reflux tube section (201); after the intubation is completed, the drainage hole (104) is located in the inferior vena cava, the superior vena cava or the right atrium.

6. The double-lumen cannula according to claim 1, characterized in that: A first through hole (105) is provided at the distal end of the drainage tube (100), and the first reflux pipe section (201) passes through the first through hole (105) and is sealedly connected to the hole wall of the first through hole (105).

7. The double-lumen cannula according to claim 1, characterized in that: The outer diameter of the first reflux pipe section (201) is smaller than the outer diameter of the drainage pipe (100); The outer wall of the first reflux pipe section (201) transitions smoothly with the outer wall of the drainage pipe (100).

8. The double-lumen cannula according to claim 7, characterized in that: The first reflux pipe section (201) and the drainage pipe (100) are integrally formed.

9. The double-lumen cannula according to claim 1, characterized in that: A second through hole (106) is provided on the side wall of the proximal end of the drainage tube (100); the reflux tube (200) passes through the second through hole (106) and extends toward the distal end of the drainage tube (100); and the drainage tube (100) is sealedly connected to the hole wall of the second through hole (106).

10. The double-lumen cannula according to claim 9, characterized in that: The included angle between the second return pipe section (202) and the third return pipe section (203) is greater than 90°.

11. The double-lumen cannula according to claim 1, characterized in that: The second return pipe section (202) and the third return pipe section (203) are integrally formed.

12. The double-lumen cannula according to claim 1, characterized in that: A first support body (208) is provided in the tube wall of the first reflux pipe section (201); the first support body (208) is used to prop open the tube wall of the first reflux pipe section (201) and enable the first reflux pipe section (201) to bend; A first support body (208) on the first return pipe section (201) at a side away from the drainage pipe (100) The density of the first support body (208) is lower than the density of the first support body (208) on the side close to the drainage tube (100), and the flexibility of the side of the first return pipe section (201) away from the drainage tube (100) is higher than the flexibility of the side close to the drainage tube (100).

13. The double-lumen cannula according to claim 4, characterized in that: The length of the reflux tube (200) is greater than that of the drainage tube (100). After the intubation is completed, the reflux hole (207) on the reflux tube (200) is located in the left atrium, and the drainage hole (104) of the drainage tube (100) is located in the right atrium.

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