Negative pressure suction device

Abstract

The application provides a negative pressure suction device, and belongs to the technical field of thrombus suction negative pressure equipment; the device comprises a handheld suction pump, a suction connecting pipe and a liquid discharge connecting pipe; the handheld suction pump has a suction part and a driving part; the suction part comprises a needle cylinder and a core rod; the driving part comprises a main handle, an auxiliary handle and an elastic reset member; the distal end of the main handle is connected with the needle cylinder, the distal end of the auxiliary handle is connected with the core rod, the main handle and the auxiliary handle are hinged through a pivot, and the elastic reset member is arranged between the main handle and the auxiliary handle; the suction connecting pipe is in communication with the suction port of the needle cylinder and is used for connecting a treatment catheter; the liquid discharge connecting pipe is in communication with the liquid discharge port of the needle cylinder and is used for discharging waste liquid sucked; a check valve is arranged in the suction connecting pipe and / or the liquid discharge connecting pipe, so as to ensure the stability of suction negative pressure; and the device is mainly used for solving the technical problems of complicated negative pressure suction operation, poor negative pressure stability and easy escape of thrombus in an intermediate catheter in the prior art.

Description

Technical Field

[0001] This invention belongs to the technical field of negative pressure thrombus aspiration equipment, and specifically relates to a negative pressure aspiration device. Background Technology

[0002] In the acute phase of cerebral infarction, endovascular thrombectomy is a key treatment for rapidly restoring cerebral blood flow. It has irreplaceable clinical value in quickly relieving cerebral vascular occlusion and restoring blood perfusion, effectively improving patient prognosis and reducing disability and mortality rates. Currently, commonly used interventional thrombectomy techniques are mainly divided into two categories: stent thrombectomy and direct thrombectomy. Although the operational pathways of the two techniques differ, both rely on a negative pressure aspiration device connected to a treatment catheter. The negative pressure is used to precisely aspirate the thrombus, preventing thrombus fragments from escaping during the procedure and ensuring the safety and effectiveness of the treatment.

[0003] Currently, the negative pressure aspiration devices used in clinical practice mainly include two types: ordinary syringes and mechanical negative pressure aspiration pumps. Although both can meet the basic negative pressure requirements in actual use, they both have some technical problems.

[0004] Conventional syringe-based negative pressure aspiration typically uses a 50ml syringe as the negative pressure generating device. During operation, the syringe tip is sealed to the end of the treatment catheter, and the operator continuously applies pressure with both hands to generate negative pressure, which is then drawn out through the catheter. This approach has several drawbacks: First, the entire procedure requires a dedicated person to apply continuous pressure with both hands, and the aspiration action must be repeated to maintain a stable negative pressure. This is difficult for a single operator to perform independently, necessitating a clinical assistant to handle the syringe operation, increasing labor costs and collaboration. Second, the stability of manual aspiration is difficult to control; the negative pressure fluctuates easily with changes in the operator's hand strength. This can lead to incomplete thrombus aspiration due to insufficient negative pressure, or damage to the vessel wall due to excessively high pressure. Third, the connection between the syringe and catheter is prone to loosening during repeated procedures, which can not only cause negative pressure leakage affecting the aspiration effect but also increase the risk of complications such as air embolism, resulting in poor overall ease of operation.

[0005] Mechanical negative pressure suction pumps, relying on their built-in mechanical structure, achieve automatic and continuous suction after being powered on, providing a relatively stable negative pressure environment and solving the problem of negative pressure fluctuations in manual suction to some extent. However, this solution also has several drawbacks: First, the high manufacturing cost of mechanical negative pressure suction pumps, coupled with the ongoing maintenance costs, makes them unaffordable for many primary healthcare institutions, limiting their clinical adoption. Second, the operation of the equipment involves specialized steps such as parameter setting and pressure adjustment, requiring highly skilled operators who must undergo systematic professional training and pass an examination before being allowed to operate the equipment, increasing the time and training costs for clinical promotion.

[0006] Furthermore, both of the existing negative pressure aspiration techniques share a common critical problem: a high risk of thrombus escape. In interventional thrombectomy procedures, an intermediate catheter and an aspiration catheter are typically used in conjunction. When the aspiration catheter is withdrawn into the intermediate catheter after thrombus capture, the intermediate catheter itself lacks negative pressure suction, making it unable to maintain continuous adhesion and fixation of the thrombus. This allows the captured thrombus to easily detach and escape from the aspiration catheter due to blood flow impact or catheter movement. Once thrombus escape occurs, it not only leads to the failure of the current thrombectomy treatment but may also cause the thrombus to travel with the bloodstream and block distal blood vessels, leading to new infarcts and seriously threatening the patient's life.

[0007] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing technology. Summary of the Invention

[0008] The purpose of this invention is to provide a negative pressure aspiration device to solve the technical problems of cumbersome operation, poor negative pressure stability, and easy escape of thrombi in the intermediate catheter in the prior art.

[0009] To achieve the above objectives, the negative pressure suction device of the present invention provides the following technical solution:

[0010] A negative pressure suction device, comprising:

[0011] A handheld suction pump has a suction part and a drive part. The suction part includes a syringe and a core rod that is axially sealed and slidably disposed inside the syringe. The drive part includes a main handle, a secondary handle, and an elastic reset member. The distal end of the main handle is connected to the syringe, and the distal end of the secondary handle is connected to the core rod. The main handle and the secondary handle are hinged by a pivot, and the elastic reset member is disposed between the main handle and the secondary handle.

[0012] A suction connecting tube, which is connected to the suction port of the syringe, is used to connect a treatment catheter;

[0013] A drain connection tube is connected to the drain port of the syringe for discharging the aspirated waste liquid;

[0014] A check valve is installed in the suction connection pipe and / or the drainage connection pipe to ensure stable suction negative pressure;

[0015] During operation, the end of the suction connection tube furthest from the suction part is connected to the treatment catheter. The suction part is driven by manually pressing the drive unit to provide negative pressure to the treatment catheter. The waste liquid aspirated from the treatment catheter is discharged through the drain connection tube.

[0016] As a further optimized technical solution, the end of the core rod that extends into the syringe has a piston, and the piston has an axially penetrating through hole in the middle, which constitutes the discharge port.

[0017] As a further optimized technical solution, the aspiration connection tube is connected to the treatment catheter through a pathway switching valve. The pathway switching valve has a switching part and multiple connection branches disposed on the switching part. The switching part is used to control the connection of at least two of the connection branches.

[0018] As a further optimized technical solution, the channel switching valve is connected to a negative pressure branch, which is used to connect to an intermediate catheter that works in conjunction with the treatment catheter.

[0019] As a further optimized technical solution, a Y-type connecting valve is provided at the proximal end of the intermediate catheter. The treatment catheter is sleeved inside the intermediate catheter through one branch interface of the Y-type connecting valve, and the negative pressure branch is connected to the lumen of the intermediate catheter through the other branch interface of the Y-type connecting valve.

[0020] As a further optimized technical solution, one of the connecting branches of the channel switching valve is connected to a flushing device.

[0021] As a further optimized technical solution, a switch valve for controlling the conduction of the negative pressure branch is provided on the negative pressure branch.

[0022] As a further optimized technical solution, a waste liquid collection component is provided at the end of the drain connection tube away from the syringe.

[0023] As a further optimized technical solution, the elastic reset element is a torsion spring.

[0024] As a further optimized technical solution, the drain connection pipe is provided with an extension component to extend the passage of the drain connection pipe.

[0025] Beneficial effects: First, in this invention, the distal end of the main handle is connected to the syringe, and the distal end of the auxiliary handle is connected to the core rod. The main handle and auxiliary handle are hinged by a pivot, thus forming a lever-type drive structure. That is, this invention replaces the traditional two-handed push-pull syringe with a lever-type manual suction pump that can be operated with one hand. Through the lever-type handheld drive design, the operator can easily generate a strong and controllable negative pressure with one hand, realizing the entire process of suction, holding, and release can be completed with one hand. This greatly liberates manpower, eliminates the dependence on additional assistants, simplifies the surgical procedure, and enables a single person to independently complete complex suction operations. This makes it possible; secondly, by installing check valves in the aspiration connection tube and / or drainage connection tube, pressure backflow and leakage are effectively prevented, ensuring a continuous and stable negative pressure environment during operation intervals and handover processes. This not only improves aspiration efficiency but also eliminates the risk of thrombus detachment caused by sudden drops in negative pressure, significantly improving surgical safety. In addition, the device has a simple structure, its manufacturing cost is significantly lower than that of mechanical negative pressure aspiration pumps, and it does not require electric drive, making maintenance convenient. This greatly reduces the equipment investment and usage threshold for medical institutions, which is conducive to the promotion and application of this advanced technology in primary hospitals and has outstanding social benefits.

[0026] Furthermore, this invention overcomes the technical deficiency of traditional negative pressure devices that only apply negative pressure to a single treatment catheter. By designing a pathway switching valve and a negative pressure branch, a dual negative pressure system is constructed. When the treatment catheter is withdrawn, a negative pressure adsorption force is generated inside the intermediate catheter, which together with the treatment catheter forms a negative pressure channel to prevent thrombus escape. This achieves seamless capture of thrombi throughout the entire process and solves a long-standing technical problem that has plagued clinical practice.

[0027] Furthermore, this invention integrates multiple functions such as suction and irrigation through a channel switching valve, allowing intraoperative irrigation and other operations to be completed without disconnecting the negative pressure connection, maintaining the continuity of the negative pressure environment, significantly shortening the operation time, and effectively improving the overall surgical efficiency. Attached Figure Description

[0028] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Wherein:

[0029] Figure 1 This is a schematic diagram of the overall structure of one embodiment of the negative pressure suction device of the present invention;

[0030] Figure 2 This is a schematic diagram of the overall structure of a handheld suction pump according to an embodiment of the negative pressure suction device of the present invention.

[0031] Figure 3 for Figure 2 Internal structure diagram of section A;

[0032] Figure 4 This is a schematic diagram of the syringe structure of one embodiment of the negative pressure suction device of the present invention;

[0033] Figure 5 This is a schematic diagram of the core rod structure of one embodiment of the negative pressure suction device of the present invention;

[0034] Figure 6 This is a schematic diagram illustrating the connection method between the core rod and the drain connection pipe in one embodiment of the negative pressure suction device of the present invention;

[0035] Figure 7 This is a schematic diagram of the check valve structure of one embodiment of the negative pressure suction device of the present invention;

[0036] Figure 8 This is a schematic diagram of the one-way flow structure of the check valve in one embodiment of the negative pressure suction device of the present invention.

[0037] Figure 9 This is a schematic diagram of a working state of an embodiment of the negative pressure suction device of the present invention;

[0038] In the diagram: 1. Syringe; 2. Core rod; 3. Main handle; 4. Secondary handle; 5. Elastic reset element; 6. Pivot; 7. Aspiration connection tube; 8. Drainage connection tube; 9. Check valve; 10. Piston; 11. Through hole; 12. Pathway switching valve; 13. Negative pressure branch; 14. Intermediate catheter; 15. Y-type connection valve; 16. Switch valve; 17. Waste liquid collection component; 18. Extension component; 19. Treatment catheter; 20. Aspiration port; 21. First connection hole; 22. Second connection hole; 23. Sealing ring. Detailed Implementation

[0039] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0040] In the description of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. The terms "connected" and "linked" used in this invention should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; they can refer to a direct connection or an indirect connection through intermediate components. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances. Furthermore, the term "proximal end" uniformly refers to the end closer to the operator, while "distal end" refers to the end farther from the operator.

[0041] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0042] The shapes and sizes of the components in the accompanying drawings do not reflect the actual proportions of the product; they are only intended to illustrate the content of the invention.

[0043] This invention provides a negative pressure aspiration device, mainly used to solve the technical problems of existing negative pressure devices, such as cumbersome operation, poor negative pressure stability, and easy thrombus escape. The negative pressure aspiration device includes a handheld aspiration pump, an aspiration connecting tube 7, and a drainage connecting tube 8. A check valve 9 is provided inside the aspiration connecting tube 7 and / or the drainage connecting tube 8. The handheld aspiration pump has an aspiration part and a drive part. The aspiration part includes a syringe 1 and a built-in sealed sliding core rod 2. The drive part is composed of a main handle 3 and a secondary handle 4 hinged by a pivot 6, with an elastic reset member 5 between them. The aspiration connecting tube 7 connects the syringe 1 to the treatment catheter 19, and the drainage connecting tube 8 connects the syringe 1 to the waste liquid collection component 17. The handheld suction pump, driven by a lever-type mechanism consisting of a main handle 3, a secondary handle 4, and an elastic reset element 5, allows for single-handed operation. Check valves 9 in the suction connection tube 7 and / or drainage connection tube 8 maintain stable negative pressure. Simultaneously, a dual negative pressure system can be constructed via the pathway switching valve 12 and the negative pressure branch 13. This negative pressure branch connects to the intermediate catheter 14 via a Y-type connecting valve 15, enabling synchronous negative pressure adsorption of the treatment catheter 19 and the intermediate catheter 14. In other words, a single negative pressure source can simultaneously apply negative pressure to both the treatment catheter 19 and the intermediate catheter 14, creating dual negative pressure adsorption during the retraction of the treatment catheter 19. This fundamentally solves the key technical problem of thrombus escape within the intermediate catheter. This device offers advantages such as ease of operation, stable negative pressure, good escape prevention, and low cost. It requires no electricity and is suitable for clinical scenarios such as interventional thrombectomy for cerebral infarction, facilitating its widespread adoption at the grassroots level.

[0044] Example 1

[0045] like Figure 1 As shown, the negative pressure suction device includes a handheld suction pump, a suction connection pipe 7, and a drain connection pipe 8.

[0046] like Figure 2 , Figure 4 , Figure 5 As shown, the handheld suction pump has a suction section and a drive section. The suction section includes a syringe 1 and a core rod 2. The core rod 2 is axially and slidably disposed within the syringe 1. Specifically, the core rod 2 has a tubular structure, and a piston 10 is fixed to one end of the core rod 2 that extends into the syringe 1. A sealing ring 23 is fitted on the outside of the piston 10 to ensure a tight seal with the inner wall of the syringe 1. In this embodiment, to ensure the positional stability of the sealing ring 23, two grooves are provided on the outer side of the piston 10, and the sealing ring 23 is installed in the grooves. In addition, the sealing ring 23 contains medical silicone oil, which can wet the sealing ring 23 and cause it to expand, so as to better fit the syringe 1 and ensure that the piston 10 slides smoothly. A through hole 11 is opened in the middle of the piston 10, axially penetrating the cavity of the core rod 2 and the outside. This through hole 11 constitutes the discharge port of the syringe 1.

[0047] The drive unit employs a lever principle design, comprising a main handle 3, a secondary handle 4, and an elastic reset member 5. The distal end of the main handle 3 is fixedly connected to the tail of the syringe 1 via a first connecting hole 21. The distal end of the secondary handle 4 is hinged to the tail of the core rod 2 via a second connecting hole 22. The main handle 3 and the secondary handle 4 are hinged together at their midpoints via a pivot 6. The elastic reset member 5 is sleeved on the pivot 6, and its two ends act on the main handle 3 and the secondary handle 4 respectively, providing a mutual opening and reset force for both. In this embodiment, as... Figure 3 As shown, the elastic reset element 5 is a torsion spring, which is sleeved on the pivot 6. One end of the connecting arm is fixedly mounted on the main handle 3, and the other end of the connecting arm is fixedly mounted on the auxiliary handle 4.

[0048] like Figure 1 , Figure 6As shown, one end of the aspiration connecting tube 7 is connected to the aspiration port 20 at the front end of the syringe 1, and the other end is used to connect to the treatment catheter 19. The drainage connecting tube 8 is connected to the drainage port of the syringe 1 and is used to drain the aspirated waste liquid. Preferably, a waste liquid collection component 17, such as a waste liquid bag or collection bottle, is connected to the end of the drainage connecting tube 8 away from the syringe 1 to facilitate the collection and treatment of waste liquid. It should be noted that in the description of this embodiment, the treatment catheter 19 specifically refers to a thrombus aspiration catheter, but in other embodiments it should be interpreted broadly to refer to any device that can perform interventional treatment through negative pressure aspiration, the core feature of which is that it has a lumen that can pass through negative pressure. Therefore, it can be an aspiration catheter specifically for thrombus aspiration, a thrombectomy catheter for capturing and removing thrombi, or a microcatheter for delivering fluids (such as contrast agents, irrigation fluids, or drugs) under negative pressure.

[0049] To ensure the stability of the negative pressure, check valves 9 are installed in both the suction connection pipe 7 and the discharge connection pipe 8. Figure 7 and Figure 8 As shown, the check valve 9 has a duckbill-shaped automatic closing structure at the end facing the waste liquid discharge, allowing the waste liquid fluid to flow from the syringe 1 towards the waste liquid collection component 17 (i.e., the discharge direction). After flowing, it automatically closes, thus strictly preventing backflow. This means that during aspiration, even if the operator releases their grip, the check valve 9 can prevent air or liquid from flowing back into the syringe 1, thereby maintaining negative pressure at the end of the treatment catheter 19.

[0050] Furthermore, the aspiration connection tube 7 is connected to the treatment catheter 19 via the access switching valve 12. The access switching valve 12 has multiple connection branches and a switching part (such as a knob) for switching access states. In this embodiment, the access switching valve 12 is a three-way valve with three connection branches. The left connection branch is connected to the treatment catheter 19, the right connection branch is connected to the aspiration connection tube 7, and the top connection branch is connected to a flushing device (not shown in the figure). The flushing device can be a syringe filled with saline. In this way, when the aspiration connection tube 7 and / or the drainage connection tube 8 are blocked by thrombus, it is only necessary to operate the access switching valve 12 to connect the flushing device with the aspiration connection tube 7, thereby facilitating rapid flushing of the tube body during the operation without disconnecting the negative pressure connection.

[0051] Furthermore, to prevent the drainage connection tube 8 from being too short, an extension component 18 (such as an extension tube) can be connected to the drainage connection tube 8 to adapt to different operating table layouts.

[0052] In practical use, the operator holds the main handle 3 with one hand and uses their fingers to press the auxiliary handle 4, squeezing the main handle 3 and auxiliary handle 4 against each other. Through leverage, the core rod 2 moves backward with minimal effort, generating negative pressure inside the syringe 1. Upon release, the handle returns to its original position under the action of the torsion spring, and the core rod 2 moves forward, expelling the waste liquid drawn into the syringe 1 through the drain port and drain connection tube 8 to the waste liquid collection component 17. The check valve 9 ensures that the negative pressure at the end of the treatment catheter 19 will not leak during the release and reset process. By repeating this pressing and releasing action, continuous and stable negative pressure aspiration can be achieved.

[0053] Example 2

[0054] Based on Example 1, such as Figure 9 As shown, this embodiment adds more complex functional integration. In this embodiment, the pathway switching valve 12 is a four-way valve. The switching part has a connecting branch in each of the four directions of circumference: up, down, left, and right. The left connecting branch is directly connected to the treatment catheter 19, the right connecting branch is connected to the suction connecting tube 7, the upper connecting branch is connected to the flushing device (not shown in the figure), and the lower connecting branch is connected to the negative pressure branch 13. The end of the negative pressure branch 13 away from the pathway switching valve 12 is used to connect to the intermediate catheter 14 that cooperates with the treatment catheter 19.

[0055] Specifically, a Y-type connecting valve 15 is provided at the proximal end of the intermediate catheter 14. The treatment catheter 19 is sleeved inside the intermediate catheter 14 through one branch interface of the Y-type connecting valve 15. The negative pressure branch 13 is connected to the lumen of the intermediate catheter 14 through the other branch interface of the Y-type connecting valve 15. In this way, the negative pressure can not only be directly applied to the treatment catheter 19, but also directly applied to the lumen of the intermediate catheter 14 through the negative pressure branch 13, thereby preventing thrombus escape when the treatment catheter 19 is withdrawn into the intermediate catheter 14.

[0056] Furthermore, a switch valve 16 for controlling the conduction of the negative pressure branch 13 is provided on the negative pressure branch 13. In order to prevent the negative pressure branch 13 from being too short, an extension component 18 is also provided on the negative pressure branch 13. In this embodiment, the switch valve 16 is provided on the extension component 18.

[0057] Specifically, during the interventional thrombectomy procedure, the intermediate catheter 14 and the treatment catheter 19 are first inserted sequentially into the target location of the patient's cerebral blood vessels, so that the distal end of the treatment catheter 19 is close to the thrombus site.

[0058] Open the left and right connecting branches of the access switching valve 12 so that negative pressure is applied directly to the treatment catheter 19 to aspirate the thrombus and draw the thrombus into the treatment catheter 19.

[0059] After the thrombus is aspirated into the treatment catheter 19, maintain the pressure on the main handle 3 and the auxiliary handle 4 to keep the negative pressure in place. Open the switch valve 16, at which point the negative pressure branch 13 is activated. Rotate the valve core of the pathway switching valve 12 to simultaneously connect the left, right, and lower connecting branches. The negative pressure in the syringe 1 is transmitted to the lumen of the intermediate catheter 14 through the negative pressure branch 13, creating a stable negative pressure within the intermediate catheter 14. At this point, slowly withdraw the treatment catheter 19, allowing it to carry the thrombus back into the lumen of the intermediate catheter 14. Due to the continuous negative pressure within the intermediate catheter 14, the thrombus is firmly adsorbed within it, preventing escape due to blood flow impact during withdrawal.

[0060] After thrombus capture is completed, close the switch valve 16, release the main handle 3 and the auxiliary handle 4. Under the reset action of the torsion spring, the core rod 2 moves to the distal end, and the waste liquid in the syringe 1 is discharged into the waste liquid collection component 17 through the through hole 11 of the piston 10 and the drain connection tube 8. If repeated aspiration is required, the main handle 3 and the auxiliary handle 4 can be pressed again to perform the next aspiration cycle.

[0061] If the suction connection tube 7 and the drainage connection tube 8 are blocked by thrombus during the operation, the flushing equipment can be connected to the suction connection tube 7 by operating the access switching valve 12. This allows for quick flushing of the tubes during the operation without disconnecting the negative pressure connection, thus maintaining the continuity of the negative pressure environment.

[0062] Example 3

[0063] This embodiment provides a different arrangement of the check valve. In this embodiment, the check valve 9 is only installed in the suction connection pipe 7 or the drain connection pipe 8.

[0064] In summary, this invention solves the problems of cumbersome operation and unstable negative pressure through a basic one-handed pump and a stable check valve design. Furthermore, by innovatively combining a pathway switching valve with a negative pressure branch, it overcomes the clinical challenge of thrombus escape within the intermediate catheter. This device is ingeniously structured, inexpensive, and highly effective, possessing significant clinical application value.

[0065] It is understood that the above description is merely exemplary and the embodiments of this application do not limit the scope of the application.

[0066] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are within the protection scope of the present invention.

Claims

1. A negative pressure suction device, characterized in that, include: A handheld suction pump has a suction part and a drive part. The suction part includes a syringe (1) and a core rod (2) axially sealed and slidably disposed inside the syringe (1). The drive part includes a main handle (3), a secondary handle (4) and an elastic reset member (5). The distal end of the main handle (3) is connected to the syringe (1), and the distal end of the secondary handle (4) is connected to the core rod (2). The main handle (3) and the secondary handle (4) are hinged by a pivot (6). The elastic reset member (5) is disposed between the main handle (3) and the secondary handle (4). A suction connecting tube (7) is connected to the suction port (20) of the syringe (1) and is used to connect the treatment catheter (19). The drain connection tube (8) is connected to the drain port of the syringe (1) and is used to drain the aspirated waste liquid. A check valve (9) is installed in the suction connection pipe (7) and / or the drain connection pipe (8) to ensure the stability of the suction negative pressure; The aspiration connection tube (7) is connected to the treatment catheter (19) through the access switching valve (12). The access switching valve (12) has a switching part and multiple connection branches provided on the switching part. The switching part is used to control the connection of at least two of the connection branches. The pathway switching valve (12) is connected to a negative pressure branch (13), which is used to connect to an intermediate catheter (14) that works with the treatment catheter (19). During operation, the end of the suction connecting tube (7) away from the suction part is connected to the treatment catheter (19). The suction part is driven by manually pressing the drive part to provide negative pressure to the treatment catheter (19). The waste liquid aspirated in the treatment catheter (19) is discharged through the drain connecting tube (8). After the treatment catheter 19 has finished aspirating, the access switching valve (12) is operated to keep both the treatment catheter (19) and the intermediate catheter (14) under negative pressure.

2. The negative pressure suction device according to claim 1, characterized in that, The end of the core rod (2) that extends into the syringe (1) has a piston (10), and the piston (10) has an axial through hole (11) in the middle, which constitutes the drain port.

3. The negative pressure suction device according to claim 1, characterized in that, The intermediate catheter (14) is provided with a Y-type connecting valve (15) at its proximal end. The treatment catheter (19) is fitted inside the intermediate catheter (14) through one branch interface of the Y-type connecting valve (15). The negative pressure branch (13) is connected to the lumen of the intermediate catheter (14) through another branch interface of the Y-type connecting valve (15).

4. The negative pressure suction device according to claim 1, characterized in that, One of the connecting branches of the channel switching valve (12) is connected to a flushing device.

5. The negative pressure suction device according to claim 1, characterized in that, The negative pressure branch (13) is equipped with a switch valve (16) for controlling the conduction of the negative pressure branch (13).

6. The negative pressure suction device according to any one of claims 1-5, characterized in that, The end of the drain connection tube (8) away from the syringe (1) is provided with a waste liquid collection component (17).

7. The negative pressure suction device according to any one of claims 1-5, characterized in that, The elastic reset element (5) is a torsion spring.

8. The negative pressure suction device according to any one of claims 1-5, characterized in that, An extension component (18) is provided on the drain connection pipe (8) to extend the passage of the drain connection pipe (8).

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