WO2025043883A1 - Dual lumen cannula - Google Patents

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

The present invention relates to the field of medical devices, and in particular to a double-lumen cannula.

Background Art

The cannula is a key component in the extracorporeal membrane oxygenation (ECMO) system that is directly connected to the human blood vessels. It is a bridge connecting the ECMO extracorporeal circulation pipeline and the human blood vessels, and plays a vital role in the normal function of the ECMO system. An ECMO system contains two cannulas, one for drawing out human venous blood, and one for returning arterial blood after oxygenation by the ECMO system to the human blood vessels. The venous-to-venous cannula VV-ECMO is a cannula treatment method commonly used by the ECMO system for patients with pulmonary failure. Usually, a single-lumen cannula is used as a drainage tube. After a femoral vein puncture operation, it is inserted into the inferior vena cava near the right atrium, and venous blood is drawn from the inferior vena cava. After oxygenation by the ECMO system, another single-lumen cannula is inserted into the superior vena cava through the internal jugular vein to return the oxygenated arterial blood to the human body. The existing VV-ECMO requires two cannulas, and two different blood vessels are cannulated through two surface puncture holes. The operation is complicated and will also increase the risk of infection for patients.

One solution is to use a double-lumen cannula, insert the return tube into the drainage tube, and integrate the drainage line for venous blood and the return line for arterial blood into one. Only one cannula is needed, which reduces the complexity of the operation and reduces the trauma to the body surface and blood vessels. However, in a double-lumen cannula, the drainage line and the return line occupy the same blood vessel, and the cross-sectional area of the line is limited, making it difficult to ensure that both the drainage line and the return line have sufficient flow cross-sectional area, and the drainage and return effect cannot be guaranteed.

Summary of the invention

In view of the deficiencies in the prior art, the object 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.

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

a drainage tube having a drainage lumen;

A return tube passes through the drainage tube, comprising a first return tube section exposed at the distal end of the drainage tube, a second return tube section built into the drainage cavity, and a third return tube section exposed at the proximal end of the drainage tube,

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, 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 spaced apart from the inner wall of the second reflux pipe segment.

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

The free portion accounts for more than 1/2 of the circumference of the distal end of the second return pipe segment.

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.

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.

Optionally, there is a gap between the outer wall of the second reflux pipe section and the inner wall of the drainage pipe;

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

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 sealed and connected to the hole wall of the first through hole.

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

The outer wall of the first reflux pipe section transitions smoothly with the outer wall of the drainage pipe.

Optionally, the first reflux pipe section and the drainage pipe are integrally formed.

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.

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

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

Optionally, a first support body is provided in the tube wall of the first reflux pipe section; the first support body is used to prop open the tube wall of the first reflux pipe section and make the first reflux pipe section bendable;

The density of the first support body on the first reflux pipe section away from the drainage pipe is lower than that on the side close to the drainage pipe, and the flexibility of the first reflux pipe section away from the drainage pipe is higher than that on the side close to the drainage pipe.

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.

The implementation of the above scheme has the following beneficial effects:

The double-lumen cannula provided by the present invention has both a drainage tube and a reflux 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 with the conventional method of forming two puncture holes on the body surface.

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

BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

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

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

FIG6 is an enlarged view of portion A in FIG5 ;

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

FIG8 is a cross-sectional view of a core guide provided in an embodiment of the present application after being withdrawn from a double-lumen cannula;

FIG. 9 is a schematic diagram of the structure of the guide core provided in an embodiment of the present application.

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

DETAILED DESCRIPTION

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 here can be arranged and designed in various different configurations.

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 claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

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 require further definition and explanation in the subsequent drawings.

In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or are the positions or positional relationships in which the inventive product 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 descriptions, 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.

In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

Embodiments of the present invention are described in detail below, and 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 only used to explain the present invention, and cannot be understood as limiting the present invention.

The present embodiment provides a double-lumen cannula, as shown in Figures 1 to 8, the double-lumen cannula includes a drainage tube 100 and a return tube 200, the drainage tube 100 has a drainage cavity 101 inside, 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, the third return tube segment 203 is exposed at the proximal end of the drainage tube 100, the second return tube segment 202 is built in the drainage cavity 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 the length of the drainage tube 100. The proximal end of the drainage tube 100 is provided with a drainage joint 102, and the third return tube segment 203 is provided with a return joint 206. 4 and 5 , 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. A gap 103 is left between the outer wall of the second reflux tube section 202 and the inner wall of the drainage tube 100, allowing venous blood entering from the drainage hole 104 to flow to the drainage connector 102 through the gap 103.

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 reflux hole 207 is used to return oxygen-rich arterial blood to the body. The positions of the drainage hole 104 and the reflux 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 the returned arterial blood, the distance between the drainage hole 104 and the reflux hole 207 can be changed to ensure that the drainage hole 104 and the reflux hole 207 can be accurately delivered to the designated position.

It should be noted that the drainage hole 104 of the double-lumen cannula is located in the inferior vena cava, the superior vena cava or the right atrium, and is used to draw venous blood into the drainage cavity 101 of the double-lumen cannula and lead it to the outside of the body, and then pass through the oxygenator to oxygenate and remove carbon dioxide to become oxygen-rich arterial blood, and finally directly perfuse into the left atrium through the return joint 206, the third return pipe segment 203, the second return pipe segment 202 and the first return pipe segment 201 by the centrifugal pump in sequence, which can reduce the burden on the heart and lungs and is used for cardiopulmonary support. Exemplarily, after the cannula is completed, the return hole 207 on the return pipe 200 is located in the left atrium, and the drainage hole 104 of the drainage tube 100 is located in the right atrium.

The first reflux pipe section 201 is sealed and connected to the drainage pipe 100, and the proximal end of the second reflux pipe section 202 is sealed and connected to the third reflux pipe section 203. The distal end of the second reflux 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 reflux pipe section 201, and the free portion 205 has a second reflux pipe section 203. The first state of the inner wall of the return pipe segment 202 and the second state of 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 connected in sequence 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 avoidance 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 the double-lumen cannula to pass through, as shown in Figure 7.

Specifically, the fixed portion 204 accounts for less than 1/2 of the circumference of the distal end of the second return pipe segment 202, and the free portion 205 accounts for more than 1/2 of the circumference of the distal end of the second return pipe segment 202, so as to ensure that after the deformation of the free portion 205, there is a large enough channel 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 a possible implementation, the fixed portion 204 accounts for 1/3 of the circumference of the distal end of the second return pipe segment 202, and the free portion 205 accounts for 2/3 of the circumference of the distal end of the second return pipe segment 202, and the fixed portion 204 is bonded to the inner wall of the second return pipe segment 202.

The second return pipe section 202 is a thin-walled deformable flexible tube, and the free portion 205 of the second return pipe section 202 can approach the fixed portion 204 after being squeezed by the guide core 300. The wall thickness of the second return pipe section 202 is less than that of the first return pipe section 201; the wall thickness of the second return pipe section 202 is less than that of the drainage tube 100. A first support body 208 is provided in the tube wall of the first return pipe section 201, and the first support body 208 is used to prop open the tube wall of the first return pipe section 201 and make the first return pipe section 201 bendable. A second support body 107 is provided in the tube wall of the drainage tube 100, and the second support body 107 is used to prop open the tube wall of the drainage tube 100 and make the drainage tube 100 bendable. Among them, 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.

The first return pipe section 201 and the drainage tube 100 are to be placed in the body. The first return pipe section 201 and the drainage tube 100 have certain support strength and flexibility, and can reach the predetermined position along the complete blood vessel pipeline. The second return pipe section 202 is built into the drainage cavity 101 and does not need to directly contact the blood vessel wall. In this embodiment, no support body is set in the second return pipe section 202. Under the condition of the same flow cross-sectional area, the wall of the second return pipe section 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.

In a possible implementation, the density of the first support 208 on the side of the first return pipe section 201 away from the drainage pipe 100 is less than the density of the first support 208 on the side close to the drainage pipe 100, and the flexibility of the side of the first return pipe section 201 away from the drainage pipe 100 is greater than the flexibility of the side close to the drainage pipe 100. In this embodiment, the density of the second support 107 at different positions on the second return pipe section 202 is adjusted so that different positions of the second return pipe section 202 correspond to different bending strengths, and the denser the second support 107, the greater the 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.

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 beneficial 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 the blood vessel wall, heart valve and other tissues during the insertion process.

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 joint of the reflux tube 200 and the drainage tube 100 , so that the blood vessel wall will not be damaged when the cannula is inserted into the blood vessel.

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 and connected to the hole 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.

Please refer to FIG3 , a second through hole 106 is further provided on the side wall of the proximal end of the drainage tube 100, and 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 the embodiment, the reflux pipe 200 is tilted at a certain angle to penetrate the drainage cavity 101 to prevent the blood from turning rapidly in the reflux pipe 200 and causing damage to blood cells. The second reflux pipe section 202 and the third reflux pipe section 203 are integrally formed. Of course, the second reflux pipe section 202 and the third reflux pipe section 203 can also be separately formed and then sealed and connected.

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 with the conventional method of forming two puncture holes on the body surface.

On the reflux pipe 200, the second reflux pipe section 202 is partially connected to the first reflux pipe section 201. When the tube is placed, the guide core 300 passes through the drainage tube 100 and the first reflux pipe section 201, and the second reflux pipe section 202 is squeezed to one side. Since the guide core 300 does not need to pass through the second reflux pipe section 202, the second reflux 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 reflux pipe section 202 is larger. Because the blood pressure of the arterial blood returned through the reflux 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 reflux tube section 202 is reduced, it will not hinder the return of arterial blood. In the present invention, when the cross-sectional area of the drainage cavity 101 is constant, the cross-sectional proportion of the reflux tube 200 in the drainage cavity 101 is reduced, thereby expanding the flow area of venous blood drainage, so that both the drainage tube 100 and the reflux tube 200 have sufficient flow cross-sectional area to ensure the drainage reflux effect.

The double-lumen catheter provided in this embodiment is inserted into the body by using a guide core. Please refer to Figure 9. The guide core 300 has a guide core through hole 301 that runs through both ends of the guide core 300. The guide core through hole 301 is used to pass the 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.

In a possible implementation, the guide core 300 includes a first guide core segment 302, a second guide core segment 303, a third guide core segment 304 and a fourth guide core segment 305 connected in sequence, and the guide core through hole 301 passes 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. 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 greater 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, and 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. Exemplarily, the first clamping portion 306 may be located on the first core segment 302 at a position connected to the second core segment 303 , and the second clamping portion 307 may be located on the third core segment 304 at a position connected to the fourth core segment 305 .

In a possible implementation, the drainage pipe includes a drainage pipe transition section 108, the drainage pipe transition section 108 is connected to the first return pipe section 201, and the outer diameter and the inner diameter of the drainage pipe transition section 108 are gradually reduced from the side away from the first return pipe section 201 to the side close to the first return pipe section 201. Referring to Figures 3 and 4, the first return pipe section 201 has a return pipe head end 209 on the side away from the second return pipe section 202, and the inner diameter of the return pipe head end 209 is gradually reduced from the side close to the second return pipe section 202 to the 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 fits against the inner wall of the return tube head end, and the second clamping portion 307 fits against the inner wall of the drainage tube transition section, so as to position the core guide 300 in the double-lumen cannula. It should be noted that the fitting surface between the core guide 300 and the double-lumen cannula should not be too large. If the fitting surface is too large, the friction between the double-lumen cannula and the core guide 300 will increase, which is not conducive to the withdrawal of the core guide 300.

The insertion process of the cannula in this embodiment includes:

1. The guide core 300 is passed through the drainage joint 102, the drainage cavity 101 and the first return pipe section 201 in sequence. At this time, the guide core 300 squeezes the second return pipe section 303 to one side, and the front end of the first guide core section 302 of the guide core 300 passes through the first return pipe section 201. The first clamping portion 306 at the rear end of the first guide core section 302 is connected to the first return pipe section 201. The inner wall of the return tube head end 209 on the guide core 300 is in contact with the inner wall of the drainage tube transition section 108, and the second clamping portion 307 on the third guide core segment 304 is in contact with the inner wall of the drainage tube transition section 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.

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

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 fits 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.

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.

When using a double-lumen cannula to guide blood, since the blood pressure of the arterial blood returned to the body from the reflux tube 200 is much greater than the blood pressure of the venous blood flowing out of the drainage tube 100, the second reflux tube section 303 can expand under the impact of the arterial blood, so that the outer wall of the second reflux tube 303 is close to the inner wall of the first reflux tube section 201, forming an arterial blood flow channel 211, ensuring that the arterial blood flows smoothly from the reflux hole 207.

Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments herein, and that various obvious changes, readjustments and substitutions can be made by 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 more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims (13)

A double-lumen cannula, characterized by comprising: A drainage tube (100) having a drainage cavity (101); A return pipe (200) passes through the drainage pipe (100), comprising a first return pipe section (201) exposed at the distal end of the drainage pipe (100), a second return pipe section (202) built into the drainage cavity (101), and a third return pipe section (203) exposed at the proximal end of the drainage pipe (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). 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). 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). 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). 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. 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). 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). 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. 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). 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°. 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. 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 reflux 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). 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.