Flow dividing device

Abstract

The invention provides a flow dividing device which comprises a guide pipe and a flexible film, and the guide pipe is communicated with a first cavity and a second cavity; the flexible membrane is connected with the catheter and used for being arranged in the first cavity. The flexible film is configured to be opened when the pressure of the second chamber is greater than that of the first chamber, so that the catheter is in a conducting state; the flexible membrane is further configured to deform to be closed when the pressure of the second chamber is smaller than that of the first chamber, so that the catheter is in a closed state. The shunting device adopts the flexible membrane as the one-way valve, and is simple in structure and convenient to process, so that the risk of thrombus in the shunting device can be reduced, and the probability of postoperative complications and infection can also be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and particularly relates to a shunt device for treating hydrocephalus. Background Art

[0002] Hydrocephalus refers to the abnormal accumulation of cerebrospinal fluid in the brain, causing excessive intracranial pressure, leading to headache, coma, and even death. Currently, the common method for treating hydrocephalus is the ventriculoperitoneal shunt technique. In this technique, the catheter of the shunt is placed in the anterior horn of the lateral ventricle of the brain through a skull drill, and then the distal end is connected to a pressure valve placed under the scalp of the head. The pressure valve is then connected to a catheter through the back of the ear, neck, and chest, and finally reaches the abdomen, so as to introduce the cerebrospinal fluid into the abdominal venous blood vessels through the catheter. This treatment method has good effects, but the failure rate of the shunt and the blockage rate of the catheter are both relatively high. At the same time, the probability of postoperative complications and infections is also relatively high.

[0003] To overcome the above problems, a new treatment method has been introduced. In this method, a shunt device is implanted at the position of the inferior petrosal sinus of the patient. By connecting the angular cistern storing cerebrospinal fluid and the jugular vein, the excessive cerebrospinal fluid accumulated in the angular cistern of the patient's brain is directly introduced into the jugular vein and then into the blood circulation, thereby reducing the intracranial pressure. The shunt device includes a distal stent portion and a proximal catheter portion. The stent portion is located in the cerebellopontine angle cistern, and the catheter portion is located in the jugular vein.

[0004] In this technology, the driving force for the cerebrospinal fluid to flow from the cerebellopontine angle cistern into the jugular vein is the pressure difference between the angular cistern and the jugular vein. However, the pressure of the jugular vein is a dynamically changing value. When the human body coughs, sneezes, or performs other actions that increase the intrathoracic pressure, the jugular vein pressure will instantaneously increase, and then the situation where the jugular vein pressure is greater than the cerebrospinal fluid pressure will occur. At this time, it will drive the fluid to flow back to the cerebral angular cistern, resulting in an increase in cerebrospinal fluid. Refer to Figure 1 , in order to prevent blood backflow, a fluid one-way control valve 200 is usually deployed in the catheter portion 100 of the shunt device. Since the outer diameter size of the catheter portion 100 is usually 0.3 mm to 0.4 mm, the structure of the one-way control valve 200 needs to be very precise and the size needs to be very small. This kind of one-way control valve 200 is deployed in the blood vessel, and the gaps and grooves in the valve body are likely to cause thrombus risks, and at the same time, it will also increase the difficulty of processing and installation. Summary of the Invention

[0005] The purpose of the present invention is to provide a shunt device. The shunt device uses a flexible membrane as a one-way valve, with a simple structure and easy processing. In this way, the risk of thrombus formation in the shunt device can be reduced, and the probability of postoperative complications and infections can also be reduced.

[0006] To achieve the above object, the present invention provides a flow dividing device, which includes a conduit and a flexible membrane. The conduit communicates with a first chamber and a second chamber; the flexible membrane is connected to the conduit and is configured to be placed in the first chamber;

[0007] The flexible membrane is configured to open when the pressure in the second chamber is greater than the pressure in the first chamber, so that the conduit is in a conducting state; the flexible membrane is also configured to deform and close when the pressure in the second chamber is less than the pressure in the first chamber, so that the conduit is in a closed state.

[0008] Optionally, the flexible membrane is a tubular structure and is connected to the conduit along its own axial direction; the inner wall of the flexible membrane is configured to separate under the impact of the fluid in the conduit, so that the flexible membrane opens, and then the conduit is conducted; the inner wall of the flexible membrane is also configured to fit together under the extrusion of the fluid outside the conduit, so that the flexible membrane closes, and then the conduit is closed.

[0009] Optionally, the flexible membrane is connected to the end of the conduit located in the first chamber; the flexible membrane has a free section away from the conduit, and the free section can fit together along its own radial direction after being pressed.

[0010] Optionally, the conduit includes a first section and a second section, and the first section, the flexible membrane and the second section are sequentially connected along the axial direction of the conduit; the flexible membrane can fit together along its own radial direction after being pressed.

[0011] Optionally, the flow dividing device further includes a flow limiting member, and the flow limiting member is arranged in the inner cavity of the conduit; the flow limiting member is used to reduce the flow rate of the fluid flowing from the first chamber to the second chamber.

[0012] Optionally, a plurality of flow channels are arranged on the flow limiting member, and all the flow channels penetrate along the axial direction of the conduit, and the inner diameter of each flow channel gradually decreases in the direction from the second chamber to the first chamber.

[0013] Optionally, the material of the flexible membrane is one or a combination of more of PTFE, ePTFE, FEP, polyester and polyethylene terephthalate.

[0014] Optionally, the flow dividing device further satisfies at least one of the following conditions:

[0015] The wall thickness of the flexible membrane in its own radial direction is 10 mm to 30 μm, and the length of the flexible membrane in the extending direction of the conduit is 15 mm to 35 mm;

[0016] The osmotic pressure of the flexible membrane is 10 kPa to 30 kPa;

[0017] The impact strength of the flexible film is 3N to 15N;

[0018] The tensile strength of the flexible film is 1N to 5N.

[0019] Optionally, the shunt device further satisfies at least one of the following conditions:

[0020] The material of the catheter is one or a combination of two of TPU and silica gel;

[0021] The outer diameter of the catheter is 0.5 to 0.8 mm;

[0022] The inner diameter of the catheter is 0.2 to 0.4 mm.

[0023] Optionally, the connection method between the catheter and the flexible film is bonding, ultrasonic welding or suturing.

[0024] The present invention provides a shunt device, including a catheter and a flexible film. The catheter communicates with a first chamber and a second chamber; the flexible film is connected to the catheter and is configured to be placed in the first chamber. The flexible film is configured to open when the pressure in the second chamber is greater than the pressure in the first chamber, so that the catheter is in a conducting state; the flexible film is also configured to deform and close when the pressure in the second chamber is less than the pressure in the first chamber, so that the catheter is in a closed state.

[0025] Compared with the complex one-way valves (such as duckbill valves, umbrella valves or air valves) in traditional catheters, this shunt device utilizes the characteristics of the flexible film being soft and easy to deform, so that the flexible film can be extruded and deformed under pressure to close the catheter, achieving the function of one-way control of the fluid in the catheter. The structure of this shunt device is simple, easy to process, and can also reduce the risk of thrombosis in the shunt device, reduce the failure rate of the shunt device, and the probability of postoperative complications and infections. Description of the Drawings

[0026] Figure 1 It is a partial structural schematic diagram of a shunt in the prior art;

[0027] Figure 2 It is an axial sectional view usage scenario schematic diagram of the shunt device in a preferred embodiment of the present invention. Among them, the a direction represents the flow direction of the fluid in the catheter when the pressure in the second chamber is greater than the pressure in the first chamber;

[0028] Figure 3 It is an axial sectional view usage scenario schematic diagram of the shunt device in a preferred embodiment of the present invention. Among them, the flexible film is in an open state;

[0029] Figure 4Schematic diagram of the axial cross - section of the flow - dividing device in a preferred embodiment of the present invention, where the flexible membrane is in a closed state;

[0030] Figure 5 Schematic diagram of the axial cross - section of the catheter and the flexible membrane in a preferred embodiment of the present invention, where the flexible membrane is in a closed state;

[0031] Figure 6 Schematic diagram of the axial cross - section of the catheter and the flexible membrane in another preferred embodiment of the present invention, where the flexible membrane is in a closed state;

[0032] Figure 7 Schematic diagram of the axial cross - section of the flow - dividing device in another preferred embodiment of the present invention, where the flexible membrane is in an open state;

[0033] Figure 8 Schematic diagram of the axial cross - section of the flow - dividing device in another preferred embodiment of the present invention from the first viewing angle, where the flexible membrane is in a closed state;

[0034] Figure 9 Schematic diagram of the axial cross - section of the flow - dividing device in another preferred embodiment of the present invention from the second viewing angle, where the flexible membrane is in a closed state;

[0035] Figure 10 Schematic diagram of the axial cross - section of the flow - dividing device in yet another preferred embodiment of the present invention;

[0036] Figure 11 Schematic diagram of the structure of the flow - limiting member in a preferred embodiment of the present invention.

[0037] In the figure: catheter part 100; one - way control valve 200;

[0038] Catheter 1; first section 11; second section 12; inner cavity 13; flexible membrane 2; free section 21; intermediate section 22; flow - limiting member 3; flow channel 31; first chamber 10; second chamber 20. Detailed implementation manners

[0039] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the accompanying drawings are all in a very simplified form and use non - precise scales, only for conveniently and clearly assisting in explaining the purpose of the embodiments of the present invention.

[0040] The terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0041] In the present invention, unless otherwise clearly specified and defined, the terms such as "mounted", "connected", "fixed", etc. shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection, or communicable with each other; it can be directly connected, or connected through an intermediate medium, and can be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] The following will describe in detail the exemplary embodiments of the present application with reference to the drawings. Without conflict, the following embodiments and the features in the embodiments can be mutually supplemented or combined.

[0043] To treat hydrocephalus, a preferred embodiment of the present invention provides a shunt device that can be implanted at the position of the inferior petrosal sinus of a patient and connect the cerebellopontine angle cistern storing cerebrospinal fluid and the jugular vein blood vessel. The excessive cerebrospinal fluid accumulated in the cerebellopontine angle cistern can flow into the jugular vein blood vessel through the shunt device, thereby reducing the intracranial pressure.

[0044] As Figure 2 shown, the shunt device of the present invention includes a catheter 1 and a flexible membrane 2. In actual use, one end of the catheter 1 is placed in the first chamber 10, and the other end is placed in the second chamber 20. The catheter 1 connects the first chamber 10 and the second chamber 20 and is used to introduce the fluid in the second chamber 20 into the first chamber 10. The flexible membrane 2 is connected to the catheter 1 and is used to be placed in the first chamber 10. The flexible membrane 2 is configured to open when the pressure in the second chamber 20 is greater than the pressure in the first chamber 10, so that the catheter 1 is in a conducting state, and then the fluid in the second chamber 20 can enter the first chamber 10 through the catheter 1. The flexible membrane 2 is also configured to be deformed by force and closed when the pressure in the second chamber 20 is less than the pressure in the first chamber 10, so that the catheter 1 is in a closed state, and then prevent the fluid in the first chamber 10 from entering the second chamber 20, that is, prevent the fluid in the catheter 1 from flowing.

[0045] It should be understood that the second chamber 20 generally refers to the subarachnoid space or the cerebellopontine angle cistern (abbreviated as CP) where cerebrospinal fluid is stored, such as Figure 2 the right region in Figure 2 ; the first chamber 10 generally refers to the inferior petrosal sinus (abbreviated as IPS) or the jugular vein (abbreviated as JV) near the jugular vein, such as Figure 2 the left region in

[0046] ; the fluid generally refers to the cerebrospinal fluid (abbreviated as CSF) stored in the subarachnoid space or the cerebellopontine angle cistern. The arrow a in Figure 4 or Figure 8 indicates the flow direction of the fluid in the catheter 1 when the pressure in the second chamber 20 is greater than the pressure in the first chamber 10.

[0047] More specifically, when the pressure in the subarachnoid space or the cerebellopontine angle cistern is greater than the pressure of the jugular vein, the cerebrospinal fluid will flow from the subarachnoid space or the cerebellopontine angle cistern along the catheter 1 and into the jugular vein or the inferior petrosal sinus through the flexible membrane 2 to reduce the cerebrospinal fluid pressure in the subarachnoid space or the cerebellopontine angle cistern, thereby reducing the intracranial pressure. When the human body coughs, sneezes or performs other actions that can increase the thoracic pressure, the increase in the thoracic pressure will cause the pressure in the jugular vein or the inferior petrosal sinus to rise instantaneously. When the pressure in the jugular vein or the inferior petrosal sinus rises to be greater than the cerebrospinal fluid pressure in the subarachnoid space or the cerebellopontine angle cistern, the flexible membrane 2 will be squeezed and closed (refer to Figure 4 or Figure 8 ), thereby achieving the function of unidirectionally controlling the fluid flow direction.

[0047] Compared with the complex unidirectional valves (such as duckbill valves, umbrella valves or air valves) in traditional catheters, this shunt device utilizes the soft and deformable characteristics of the flexible membrane 2, so that the flexible membrane 2 can be squeezed and deformed under the action of the fluid pressure to close the catheter 1 (even when the catheter 1 is in an unopened state), achieving the function of unidirectionally controlling the fluid in the catheter 1.

[0048] Specifically, this shunt device uses the flexible membrane 2 as a unidirectional valve. The flexible membrane 2 can automatically open when the pressure in the second chamber 20 is greater than the pressure in the first chamber 10 and automatically close when the pressure in the second chamber 20 is less than the pressure in the first chamber 10, thereby realizing the automatic control of the opening and closing of the catheter 1 to prevent fluid backflow. The structure of this shunt device is simple, easy to process, and can also reduce the risk of thrombosis in the shunt device, reduce the failure rate of the shunt device, and the probability of postoperative complications and infections.

[0049] Refer to Figure 2As shown, in a preferred embodiment, the flexible membrane 2 is configured as a tubular structure and connected to the catheter 1 in its own axial direction, that is, the flexible membrane 2 is connected to the catheter 1 in the axial direction of the catheter 1. The inner wall of the flexible membrane 2 is used to separate under the impact of the fluid in the catheter 1, so that the flexible membrane 2 is opened, and then the catheter 1 is connected. The inner wall of the flexible membrane 2 is also used to fit under the pressure of the fluid outside the catheter 1, so that the flexible membrane 2 is closed, and then the catheter 1 is closed.

[0050] Specifically, since the material of the flexible membrane 2 is relatively soft and easy to deform, when the pressure in the first chamber 10 increases, since the pressure in the first chamber 10 is greater than the pressure in the conduit 1 (at this time, the pressure in the conduit 1 is the pressure before the first chamber 10 is pressurized), the inner walls of the flexible membrane 2 at the relative position will deform under the pressure of the external fluid and fit together to seal the inner cavity of the conduit 1, so that the flexible membrane 2 is closed and can prevent the fluid from passing through. When the pressure in the second chamber 20 increases, since the pressure in the second chamber 20 is greater than the pressure in the conduit 1 (at this time, the pressure in the conduit 1 is equal to the pressure before the second chamber 20 is pressurized), the fluid in the second chamber 20 can enter the first chamber 10 through the conduit 1, and in this process, the fluid can impact the flexible membrane 2, so that the flexible membrane 2 opens and allows the fluid to pass through.

[0051] To ensure that the flexible membrane 2 has appropriate softness so that the flexible membrane 2 can be deformed under the pressure of the fluid, the material of the flexible membrane 2 is preferably a combination of one or more of PTFE (polytetrafluoroethylene), ePTFE (expanded polytetrafluoroethylene), FEP (fluorinated ethylene propylene copolymer), polyester and polyester.

[0052] To ensure that the flexible membrane 2 can automatically close after being stressed, the length of the flexible membrane 2 in the extension direction of the catheter 1 is preferably 15 mm to 35 mm. At the same time, to ensure that the flexible membrane 2 does not break or damage after being pressed, the wall thickness of the flexible membrane 2 in its own radial direction is preferably 10 mm to 30 um, the osmotic pressure of the flexible membrane 2 is preferably 10 kPa to 30 kPa, the impact strength of the flexible membrane 2 is preferably 3N to 15N, and the tensile strength of the flexible membrane 2 is preferably 1N to 5N.

[0053] To facilitate the delivery of the catheter 1 and the connection with the flexible membrane 2, the material of the catheter 1 is preferably one or a combination of TPU (thermoplastic polyurethane elastomer rubber) and silicone. The outer diameter of the catheter 1 is preferably 0.5-0.8 mm, and the inner diameter of the catheter 1 is preferably 0.2-0.4 mm.

[0054] The present application does not limit the connection method between the catheter 1 and the flexible membrane 2. For example, the connection method between the catheter 1 and the flexible membrane 2 can be selected from bonding, ultrasonic welding, suturing or other suitable connection methods.

[0055] Reference Figures 3 to 6As shown, in a specific embodiment, the flexible membrane 2 is connected to the end of the catheter 1 located in the first chamber 10, that is, the flexible membrane 2 is arranged at one end of the catheter 1 located in the first chamber 10. At this time, the flexible membrane 2 has a free section 21 away from the catheter 1, and the free section 21 of the flexible membrane 2 can be mutually attached along its own radial direction after being pressed, so that the flexible membrane 2 is closed.

[0056] It should be noted that since the flexible membrane 2 is relatively soft, the flexible membrane 2 has randomness when it is closed, that is, the shape and closing position of the flexible membrane 2 when it is closed are uncertain. In one example, the closing position of the free section 21 of the flexible membrane 2 is approximately located on the axis of the catheter 1 (refer to Figure 4 ). In another example, the closing position of the free section 21 of the flexible membrane 2 can also deviate slightly or significantly from the axis of the catheter 1 (refer to Figure 5 or Figure 6 ).

[0057] Refer to Figure 7 As shown, in another specific example, the catheter 1 includes a first section 11 and a second section 12. The first section 11, the flexible membrane 2 and the second section 12 are sequentially connected along the axial direction of the catheter 1, and the flexible membrane 2 can be mutually attached along its own radial direction after being pressed.

[0058] Refer to Figure 8 and Figure 9 As shown, in this embodiment, the flexible membrane 2 has an intermediate section 22 away from the first section 11 and the second section 12 respectively, and the intermediate section 22 can be mutually attached along its own radial direction after being pressed.

[0059] More specifically, after the pressure in the first chamber 10 increases, since the pressure of the fluid in the first chamber 10 is greater than the pressure of the fluid in the catheter 1, the inner walls of the intermediate section 22 of the flexible membrane 2 can be deformed and mutually attached under the pressure of the fluid in the first chamber 10 to close the inner cavity of the catheter 1, so that the flexible membrane 2 is closed and can prevent the fluid from passing through. In this way, the randomness after the flexible membrane 2 is deformed under pressure when it is located at the end of the catheter 1 can be avoided, so the opening and closing of the flexible membrane 2 can be better controlled to realize the one-way control of the fluid, and the risk that the flexible membrane 2 fails to close after being pressed can be reduced.

[0060] Refer to Figure 10 As shown, in a preferred example, the shunt device further includes a flow limiting member 3. The flow limiting member 3 is arranged in the inner cavity 13 of the catheter 1 and is preferably placed at one end of the catheter 1 located in the first chamber 10. The flow limiting member 3 is used to reduce the flow rate of the fluid flowing from the first chamber 10 to the second chamber. In this way, the rate of the fluid flowing from the jugular vein into the catheter 1 can be effectively slowed down to prevent the situation that the fluid quickly passes through the catheter 1 and the flexible membrane 2 in extreme cases, resulting in the flexible membrane 2 not having enough time to close.

[0061] In this embodiment, the flow limiter 3 is placed at one end of the catheter 1 located in the first chamber 10. At this time, the flow limiter 3 is used to reduce the flow rate of the fluid entering the first chamber 10.

[0062] Referring to Figure 11 As shown, as a preferred embodiment, the flow limiter 3 is provided with a plurality of flow channels 31. All the flow channels 31 penetrate along the axial direction of the catheter 1. The inner diameter of each flow channel 31 gradually decreases in the direction from the second chamber 20 towards the first chamber 10 to reduce the rate of fluid flowing from the first chamber 10 to the second chamber 20. In one example, the flow channel 31 can be a conical structure, and the inner diameter of the conical structure gradually increases in the direction from the first chamber 10 towards the second chamber 20.

[0063] The number of the flow channels 31 on the flow limiter 3 in this application is not limited. The number of the flow channels 31 can be set to 3 (refer to Figure 11 ), or can be set to 1, 2 or more.

[0064] In summary, the present invention provides a flow splitting device. The flow splitting device utilizes the characteristics of the flexible membrane 2 being soft and easily deformable, so that the flexible membrane 2 can be extruded and deformed under pressure to close the catheter 1, achieving the function of unidirectional control of the fluid in the catheter 1. The structure of the flow splitting device is simple and easy to process. It can also reduce the risk of thrombus formation in the flow splitting device, reduce the failure rate of the flow splitting device, and the probability of postoperative complications and infections.

[0065] The above description is only a description of the preferred embodiments of the present invention, and does not limit the scope of the present invention in any way. Any changes and modifications made by those of ordinary skill in the field of the present invention according to the above disclosure are within the protection scope of the present invention.

Claims

1. A flow splitting device, characterized in that, It includes a catheter and a flexible membrane. The catheter communicates with a first chamber and a second chamber. The flexible membrane is connected to the catheter and is configured to be placed in the first chamber. The flexible membrane is configured to open when the pressure in the second chamber is greater than the pressure in the first chamber, so that the catheter is in a conducting state. The flexible membrane is also configured to deform and close when the pressure in the second chamber is less than the pressure in the first chamber, so that the catheter is in a closed state.

2. The flow splitting device according to claim 1, wherein The flexible membrane is a tubular structure and is connected to the catheter along its own axial direction. The inner wall of the flexible membrane is configured to separate under the impact of the fluid inside the catheter, so that the flexible membrane opens and then conducts the catheter. The inner wall of the flexible membrane is also configured to fit together under the extrusion of the fluid outside the catheter, so that the flexible membrane closes and then seals the catheter.

3. The flow splitting device according to claim 2, characterized in that, The flexible membrane is connected to the end of the catheter located in the first chamber. The flexible membrane has a free section away from the catheter, and the free section can fit together along its own radial direction under pressure.

4. The flow splitting device according to claim 2, characterized in that, The catheter includes a first section and a second section. The first section, the flexible membrane, and the second section are sequentially connected along the axial direction of the catheter. The flexible membrane can fit together along its own radial direction under pressure.

5. The flow splitting device according to any one of claims 1-4, characterized in that, It further includes a flow-limiting member. The flow-limiting member is arranged in the inner cavity of the catheter. The flow-limiting member is used to reduce the flow rate of the fluid flowing from the first chamber to the second chamber.

6. The flow dividing device according to claim 5, wherein The flow-limiting member is provided with a plurality of flow channels. All the flow channels penetrate along the axial direction of the catheter, and the inner diameter of each flow channel gradually decreases in the direction from the second chamber towards the first chamber.

7. The flow splitting device according to any one of claims 1-4, characterized in that, The material of the flexible membrane is one or a combination of more of PTFE, ePTFE, FEP, polyester, and polyethylene terephthalate.

8. The flow splitting device according to claim 7, wherein The shunt device also satisfies at least one of the following conditions: The wall thickness of the flexible membrane in its own radial direction is 10 mm to 30 μm, and the length of the flexible membrane in the axial direction of the catheter is 15 mm to 35 mm. The osmotic pressure of the flexible membrane is 10 kPa to 30 kPa. The impact strength of the flexible membrane is 3 N to 15 N. The tensile strength of the flexible membrane is 1 N to 5 N.

9. The flow dividing device according to any one of claims 1-4, characterized in that, The shunt device also satisfies at least one of the following conditions: The material of the catheter is one or a combination of two of TPU and silica gel. The outer diameter of the catheter is 0.5 to 0.8 mm. The inner diameter of the catheter is 0.2 to 0.4 mm.

10. The flow splitting device according to any one of claims 1-4, characterized in that, The connection method between the catheter and the flexible membrane is bonding, ultrasonic welding, or suturing.

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