Detachable ultrafiltration bypass structure and safety monitoring method for ECMO tubing

Abstract

This invention relates to the field of interventional medical device technology, specifically to a detachable ultrafiltration bypass structure and safety monitoring method for ECMO tubing. It includes a bypass tube and sealing disconnectors at both ends. An ultrafiltration device, an venting device, a blood pump, an ultrasonic bubble detector, and a three-way valve are connected in series on the bypass tube. The sealing disconnectors allow for "connection upon installation and sealing upon disassembly," eliminating the need to disconnect the main circulation during installation. The venting unit and pressure sensing unit of the ultrafiltration device monitor and actively expel air emboli within the fiber optic tubing, and the venting device continuously removes gas. The ultrasonic bubble detector serves as the final safety barrier; upon detecting bubbles, it immediately switches the three-way valve, directing gas-containing blood into the isolation unit and urgently stopping the ultrafiltration pathway to prevent gas from entering the patient's body. This invention achieves full-process gas safety control from installation and operation to reinfusion through dual pressure and liquid level monitoring, automatic venting, and emergency interception multi-level protection, significantly improving the ease of operation, continuity, and safety of ECMO combined with ultrafiltration therapy.

Description

Technical Field

[0001] This invention patent relates to the field of interventional medical device technology, and more specifically, to a detachable ultrafiltration bypass structure and safety monitoring method for ECMO tubing. Background Technology

[0002] Extracorporeal membrane oxygenation (ECMO) is a percutaneous extracorporeal life support technology that can rapidly improve tissue perfusion in patients with cardiopulmonary failure, buying time for subsequent treatment and is hailed as a "lifesaver" in the field of critical care. Early fluid resuscitation during ECMO can quickly restore blood pressure and tissue perfusion; however, early, large-volume rapid fluid resuscitation can dilute clotting factors in the blood, reduce blood viscosity, and cause blood clot displacement, increasing the risk of bleeding and thromboembolism. Furthermore, its effectiveness in treating acute renal failure has been consistently unsatisfactory. Once the patient's circulation is stable, combining ECMO with ultrafiltration can effectively concentrate the blood, alleviate volume overload, remove oxygen free radicals, inflammatory mediators, and excess water from the blood, increase plasma colloid osmotic pressure, reduce pulmonary edema and interstitial edema, restore fluid balance, reduce complications caused by hemodynamic fluctuations, and rapidly improve cardiac function. For connecting ultrafiltration during ECMO operation, the current mainstream approach is to connect a separate ultrafiltration bypass tubing system to the ECMO main circulation loop, typically via a standard tee connector with a lateral thread. However, the existing method has serious shortcomings in terms of ease of operation, standardization, and safety: Traditional ECMO ultrafiltration connection requires at least one bag of normal saline (no less than 200ml), one infusion set tubing, four T-connectors, one temporary connecting tube, and one 20ml syringe. The operation is performed by at least two experienced extracorporeal circulation physicians. To avoid interrupting the ECMO main circulation, the clinician must install two T-connectors in series at the existing T-connector inlet and outlet, forming a temporary connection stack together with the connecting tube. Subsequently, normal saline is introduced through the infusion set to perform a time-consuming and skill-dependent manual pre-filling and purging operation on the ultrafiltration bypass tubing to remove all air from the ultrafiltration tubing. Finally, when connecting to the ECMO main circulation, a 20ml syringe is needed to purge air from the main circulation interface. Only after completing this series of complex pre-filling and purging steps can the bypass tubing be finally connected to the ECMO tubing. Therefore, the entire traditional connection process is complicated, time-consuming and labor-intensive, and highly dependent on the operator's experience. Not only are there no standardized operating procedures and exhaust evaluation standards, but more seriously, any oversight in any step may directly lead to air entering the circulation system or causing pipeline contamination, posing a great safety hazard.

[0003] Secondly, there are multiple risks of air embolism during operation, but the system lacks an effective response mechanism: during bypass operation, gas is easily generated and accumulated in multiple stages, with the main generation and accumulation locations concentrated in the following three places: (1) inside the ultrafilter, due to pressure and temperature changes when ECMO high-flow-rate blood flows through the hollow fiber bundle, dissolved gas is released to form "intra-membrane air emboli," directly blocking the filter membrane; (2) at the pipeline connection, gas may be introduced due to the aforementioned complex operation or poor sealing; (3) in the blood flow field, microbubbles are generated due to turbulence and cavitation effects. The existing bypass structure only relies on a simple degassing pot for passive gravity degassing, which is completely unable to monitor and actively eliminate the above-mentioned air emboli, especially those inside the ultrafilter. Therefore, there is an urgent clinical need for an intelligent ultrafiltration bypass structure that can achieve rapid, standardized, one-step installation and disassembly, and can monitor, warn, and automatically eliminate gas from the source of gas generation in real time, so as to fundamentally ensure the continuity, safety, and reliability of ECMO-ultrafiltration combined therapy.

[0004] A search revealed that existing technological improvements to address the air embolism problem in ECMO ultrafiltration bypass mainly revolve around two directions: "venting structure" and "monitoring and early warning," but neither has formed a complete solution. On the one hand, regarding the venting structure, existing designs primarily focus on initial venting and cannot address internal air emboli generated during treatment. For example, the ultrafiltration device during extracorporeal membrane oxygenation disclosed in Chinese patent (CN201743989U) has a cumbersome venting process that relies entirely on manual operation. It is mainly used in the pre-filling stage of the tubing before treatment and lacks effective clearance capabilities for stubborn "air emboli" that dynamically form and cause blockages within the ultrafilter during treatment; its function is passive and limited. On the other hand, while existing solutions can identify risks, they cannot perform subsequent processing. For instance, US patent (US2022 / 0080093A1) discloses a device for simultaneous extracorporeal membrane oxygenation and continuous renal replacement therapy, which integrates sensors and controllers to build an intelligent monitoring system capable of triggering alarms for multiple abnormal parameters, including air bubbles. However, the system only provides "risk warning" and lacks a physical mechanism to actively intervene and remove air embolisms after an alarm is triggered.

[0005] To address the problems in existing technologies, the applicant provides a detachable ultrafiltration bypass structure and safety monitoring method for ECMO tubing, which aims to integrate intelligent monitoring and active venting functions into a convenient detachable bypass, thereby simplifying connection operations while enabling real-time early warning and automatic removal of air embolism risks. Summary of the Invention

[0006] The purpose of this invention is to provide a detachable ultrafiltration bypass structure and safety monitoring method for ECMO tubing. This bypass structure achieves rapid installation and disassembly in one step through an innovative sealed disassembly joint, effectively preventing air introduction into the system while ensuring convenient installation and disassembly. Furthermore, this structure integrates self-pre-filling and venting functions with continuous monitoring and venting during operation, thereby achieving end-to-end gas elimination from installation to operation. This invention can conveniently and proactively prevent and remove air embolisms, ensuring treatment safety.

[0007] The present invention is implemented as follows: a detachable ultrafiltration bypass structure and safety monitoring method for ECMO tubing, including a bypass pipe and two sealing disassembly joints, the two sealing disassembly joints being installed on the inlet and outlet ends of the bypass pipe, and the two sealing disassembly joints being respectively installed on two T-joints of the ECMO tubing; An ultrafiltration device, an exhaust device, a blood pump, and a three-way valve are connected in series on the bypass tube. The common end and one of the reversing ends of the three-way valve are installed on the bypass tube. The other reversing end of the three-way valve is equipped with a backflow blocking unit. A bubble detector is installed upstream of the backflow blocking unit on the bypass tube. When the bubble detector detects bubbles in the blood, the three-way valve reverses, allowing the blood to flow into the backflow blocking unit and preventing the blood from flowing back into the ECMO main circulation tube. The ultrafiltration unit is equipped with a pressure sensing unit at the liquid outlet and an exhaust unit at the top of the ultrafiltration unit; An automatic exhaust valve is installed on the top of the exhaust device.

[0008] Furthermore, the sealing disassembly joint includes a rotary joint, a sealing nut, and a top-opening valve core; the rotary joint is rotatably connected to the bypass pipe; the sealing nut has a through hole, the position of which is detachably connected to the rotary joint; the top-opening valve core can communicate after the rotary joint and the sealing nut are connected, and can automatically close the through hole of the sealing nut after separation.

[0009] Furthermore, the top-opening valve core includes a push rod, a sealing plate, and a spring; the push rod is horizontally installed at the end of the rotary joint; the fixed end of the spring is installed in the sealing nut, and the free end of the spring is fixedly connected to the sealing plate. In its natural state, the sealing plate is pulled by the spring to block the through hole of the sealing nut.

[0010] Furthermore, the top-opening valve core is a duckbill valve, which is fixedly installed in the through hole of the sealing nut. When the rotary joint is rotated and fixedly installed on the sealing nut, the duckbill valve can be opened to achieve connection with the tee joint.

[0011] Furthermore, the backflow blocking unit is a backflow pipe, one end of which is connected to the reversing end of the three-way valve, and the other end is connected to the liquid inlet end of the bypass pipe.

[0012] Furthermore, the pressure sensing unit includes a hydraulic transmission chamber and two differential pressure sensing pistons; the hydraulic transmission chamber is connected to the liquid outlet of the ultrafiltration device, and the two differential pressure sensing pistons are slidably disposed in the hydraulic transmission chamber, forming a sealed chamber between the two differential pressure sensing pistons, which is filled with transmission fluid.

[0013] Furthermore, the automatic exhaust valve includes a connecting rod and an exhaust valve plate. The two ends of the connecting rod are connected to the exhaust valve plate and the differential pressure sensing piston, respectively. The exhaust valve plate is attached to the exhaust hole at the top of the exhaust device and blocks the exhaust hole. When the pressure at the outlet of the ultrafiltration device decreases, the exhaust valve plate can be pulled under the negative pressure to open the exhaust hole of the exhaust device.

[0014] Furthermore, the exhaust unit includes a duct pipe and a second gas collection hood. The second gas collection hood is fixedly installed on the top of the ultrafiltration device. The side wall of the second gas collection hood is connected to the duct pipe. The end of the duct pipe away from the second gas collection hood is located on the exhaust hole at the top of the exhaust device. When the exhaust valve plate is in contact with the top surface of the exhaust device, it simultaneously seals the duct pipe.

[0015] Furthermore, the automatic exhaust valve includes a gas collection hood, an exhaust pipe, a sealed container, a connecting rod, a float, a guide pipe, and an L-shaped pressure balance pipe; one side wall of the gas collection hood is connected to the exhaust pipe, the guide pipe is fixed to the bottom of the exhaust pipe, and its side wall is provided with several orifices; one end of the pressure balance pipe is connected to the bottom of the exhaust pipe, and the pressure balance pipe and the exhaust pipe are filled with liquid; the float is located in the guide pipe and can float with the rise and fall of the liquid level.

[0016] This invention also provides a method for safety monitoring of detachable ultrafiltration bypass emboli in ECMO tubing, the specific method being as follows: S1: System pre-filling and initial venting. Connect the sealing and disassembly connector of the bypass tube inlet end to the three-way connector of the ECMO main circulation line, start the blood pump, and adjust the three-way valve through the controller to connect the bypass tube to the reflux blocking unit. S2: Connection confirmation and pipeline establishment. When the bubble detector detects no bubbles in the flowing blood, the controller adjusts the three-way valve to form a connecting pipeline through the bypass pipe, and the blood flows to the outlet end through the bypass pipe. Connect the sealing and disassembly connector at the outlet end to the corresponding three-way connector of the ECMO main circulation pipeline to complete the system pre-filling and initial venting. S3: Operation monitoring and active venting. During continuous operation, the pressure sensing unit monitors the pressure at the outlet of the ultrafiltration device in real time. When the pressure value drops to the system's set threshold, the controller determines that an air embolism has occurred in the fiber tube inside the ultrafiltration device and controls the venting unit to open. At the same time, the bubble detector monitors the blood about to flow back into the ECMO main circulation tubing in real time. If a bubble is detected, the controller immediately switches the flow path of the three-way valve and triggers an alarm, allowing the blood containing the bubble to flow into the backflow blocking unit to prevent it from entering the patient's circulation.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention integrates a quick-release connector with automatic sealing function, a pressure-sensing linkage exhaust valve, and a flow path switching structure triggered by air bubbles into the bypass circuit, forming a system solution that combines ease of operation, operational reliability, and safety assurance. This structure enables quick, one-step installation and disassembly, fundamentally avoiding the risk of air introduction due to multiple steps in traditional cumbersome connection operations. Its built-in intelligent pressure monitoring and purely mechanical automatic exhaust mechanism can actively identify and remove air embolisms formed inside the ultrafilter, effectively preventing membrane blockage in the fiber tube and ensuring continuous and stable operation of the ultrafiltration function. The ultrasonic bubble detector and three-way valve linkage mechanism located before blood return form the final safety barrier, ensuring that no gas can enter the patient's body. The overall solution integrates monitoring, exhaust, and safety interception functions, significantly improving the safety, operational efficiency, and clinical controllability of continuous ultrafiltration during extracorporeal membrane oxygenation (ECMO) therapy with simple and reliable mechanical and control logic.

[0018] 2. In the sealing and disassembly joint, a closable top-opening valve core is provided at the through hole of the sealing nut. A rotary joint is rotatably connected to the end of the bypass pipe, and the rotary joint is threadedly connected to the sealing nut. When the rotary joint is unscrewed from the sealing nut, the sealing nut and the top-opening valve core jointly seal the lateral interface of the tee joint; when the rotary joint is fully screwed into the through hole of the sealing nut, its end opens the valve core, and a sealing fit is formed between the rotary joint and the sealing nut, achieving a reliable seal while connecting the bypass pipe to the tee joint. This structure effectively prevents external gas from entering the bypass pipe during the connection process.

[0019] 3. An exhaust unit is installed at the top of the ultrafiltration device, and a pressure sensing unit is installed at the liquid outlet. The pressure sensing unit is linked to the automatic exhaust valve on the exhaust device, and the exhaust unit is connected to the exhaust port of the exhaust device through a gas guide pipe. When an air embolism forms in the upper part of the fiber tube inside the ultrafiltration device, the gas can be guided through the exhaust unit to the exhaust device for discharge; while the air embolism attached to the liquid outlet of the fiber tube flows into the exhaust device with the blood. Based on this, through real-time monitoring of the outlet pressure by the pressure sensing unit and its linkage control with the automatic exhaust valve, simultaneous identification and discharge of air embolisms at different locations in the fiber tube can be achieved, thereby significantly improving the thoroughness of air embolism removal and the reliability of system operation.

[0020] 4. The reflux blocking unit is configured as a reflux tube, with its two ends connected to a bypass tube and a reversing end of a three-way valve, respectively. Combined with monitoring by an ultrasonic bubble detector, when air bubbles are detected in the blood at the ultrafiltration bypass outlet, the control system drives the three-way valve to switch the flow path, allowing the blood to return to the inlet end of the bypass tube via the reflux tube. This design, on the one hand, prevents air bubbles from entering the ECMO main circulation in emergency situations, and on the other hand, allows the blood to flow again through the degassing device for secondary treatment, thereby ensuring that the blood returning to the patient does not contain air emboli.

[0021] 5. The exhaust device is designed as a hydrocyclone and installed at the inlet end of the ultrafiltration unit. An automatic exhaust valve is located at the top of the hydrocyclone. As blood flows through, the hydrocyclone actively separates and collects the contained gas at the top, which is then discharged through the automatic exhaust valve. This design ensures that the blood entering the ultrafiltration fiber tube is pre-treated to remove gas, significantly reducing the formation of air embolisms inside the ultrafiltration fiber tube. This achieves source prevention of air embolism problems and improves the stability and safety of the ultrafiltration process. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the tee joint in the ECMO pipeline provided in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the detachable ultrafiltration bypass structure for ECMO tubing provided in Embodiment 1 of the present invention; Figure 3 yes Figure 2 Enlarged view of point A in the middle; Figure 4 yes Figure 2 Enlarged view of point B in the middle; Figure 5 This is a block diagram of the safety monitoring system for the detachable ultrafiltration bypass vent in the ECMO tubing in Embodiment 1 of the present invention; Figure 6 This is a schematic diagram of the sealing disassembly joint provided in Embodiment 2 of the present invention; Figure 7 This is a schematic diagram of the detachable ultrafiltration bypass structure for ECMO tubing provided in Embodiment 3 of the present invention; Figure 8 This is a schematic diagram of the detachable ultrafiltration bypass structure for ECMO tubing provided in Embodiment 4 of the present invention; Figure 9 yes Figure 8 Enlarged view of point A in the middle; Figure 10 This is a schematic diagram of the detachable ultrafiltration bypass structure for ECMO tubing provided in Embodiment 5 of the present invention; Figure 11 This is a horizontal cross-sectional view of the knob in Embodiment 5 of the present invention; Figure 12 This is a schematic diagram of the detachable ultrafiltration bypass structure for ECMO pipelines provided in Embodiment 6 of the present invention.

[0023] Reference numerals used in the above figures: 1. Main circulation loop; 2. T-joint; 3. Bypass pipe; 4. Ultrafilter body; 5. Collector chamber; 6. Electronic exhaust valve; 7. Distribution chamber; 8. Fiber tube; 9. Pressure sensor; 10. Liquid level sensor; 11. Exhaust chamber; 12. Blood pump; 13. Ultrasonic bubble detector; 14. T-valve; 15. Isolation bag; 16. Spring; 17. Rotary joint; 18. Sealing nut; 19. Push rod; 20. Sealing plate ; 21. Exhaust pipe; 22. Sealing block; 23. Connecting rod; 24. Float; 25. Pressure balance pipe; 26. Guide pipe; 27. Gas collection hood one; 28. Connecting hole; 29. ​​Duckbill valve; 30. Return pipe; 31. Gas collection hood two; 32. Air guide pipe; 33. Hydraulic transmission chamber; 34. Differential pressure sensing piston; 35. Connecting rod; 36. Exhaust valve plate; 37. Exhaust port; 38. Swirl; 39. Blood perfusion device. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0025] The implementation of the present invention will be described in detail below with reference to specific embodiments.

[0026] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this invention, it should be understood that if terms such as "upper," "lower," "left," and "right" 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 this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting this invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0027] Reference Figure 1-12 The image shown is a preferred embodiment of the present invention.

[0028] Example 1: A detachable ultrafiltration bypass structure for ECMO tubing, mainly composed of a bypass pipe 3 and two sealing disassembly joints. The two sealing disassembly joints are fixedly installed at the inlet and outlet ends of the bypass pipe 3, respectively.

[0029] Currently, ECMO main circulation lines are typically equipped with a tee fitting 2 (e.g. Figure 1 As shown in the figure, its side opening uses a nut to achieve a detachable seal, facilitating the installation of the bypass pipe 3. The sealing and disassembly connector in this embodiment is based on the existing tee connector 2 design, achieving the effect of "connection upon installation, sealing upon disassembly," as shown in the figure. Figure 3 As shown.

[0030] The sealing and disassembly joint mainly consists of a rotary joint 17, a sealing nut 18, and a top-opening valve core. The outer diameter of the constricted section of the rotary joint 17 matches the inner diameter of the bypass pipe 3, allowing it to be inserted into the bypass pipe 3. A raised ring is provided on the outer side of the rotary joint 17, which is rotatably fitted into the inner wall of the bypass pipe 3, thus achieving a sealed rotary connection between the rotary joint 17 and the bypass pipe 3. The other end of the rotary joint 17 also has a constricted section on its outer side, with external threads machined on its surface. The sealing nut 18 has a through hole with internal threads on its inner wall, allowing for threaded connection with the rotary joint 17. The sealing nut 18 can be directly snapped on or threaded onto the side opening of the tee joint 2; the specific design can be adapted to the actual tee joint 2 used.

[0031] The top-opening valve core, as a linkage structure, is integrated between the rotary joint 17 and the sealing nut 18, and its specific composition is as follows: Figure 3 As shown. The top-opening valve core mainly consists of a push rod 19, a sealing plate 20, and several springs 16. The push rod 19 is fixed to one end of the rotary joint 17 near the sealing nut 18 by a bracket, arranged horizontally and extending out of the rotary joint 17. The sealing plate 20 and springs 16 are both mounted on the sealing nut 18. One end of the spring 16 is fixed inside the side wall of the sealing nut 18, and the other end is connected to the sealing plate 20. When the push rod 19 separates from the sealing plate 20, the sealing plate 20 closes the through hole of the sealing nut 18 under the tension of the spring 16. The size of the sealing plate 20 is smaller than the diameter of the side opening of the tee joint 2. When the rotary joint 17 is fully screwed into the sealing nut 18, the push rod 19 will push the sealing plate 20 open, thereby connecting the tee joint 2 with the bypass pipe 3.

[0032] In this embodiment, the rotary joint 17 needs to rotate a certain distance before the push rod 19 contacts and pushes open the sealing plate 20. Considering that the blood flow rate in the bypass tube 3 (i.e., the ultrafiltration bypass) in this embodiment is usually within the clinically common range of 100-300 mL / min, the selected spring 16 should have enough stiffness to ensure that the sealing plate 20 will not be accidentally pushed open under the blood pressure corresponding to this flow rate when the rotary joint 17 and the sealing nut 18 are sealed together but the sealing plate 20 has not yet been pushed open. This design allows the pre-filling and venting operations to be completed independently at the sealing disassembly joint at the outlet end of the bypass tube 3 during the pre-filling and venting of the bypass structure, further ensuring the airless state of the pipeline system.

[0033] In this embodiment, the bypass tube 3 is sequentially connected in series from upstream to downstream along the blood flow direction, including an ultrafiltration device, an exhaust device, a blood pump 12, an ultrasonic bubble detector 13, and a three-way valve 14. The inlet and outlet ends of the ultrafiltration device are connected to the bypass tube using standardized interfaces (such as threaded interfaces). Since the inlet and outlet ends of the hemoperfusion device also use the same standardized interfaces, the operator can choose to install either an ultrafiltration device or a hemoperfusion device based on the patient's specific condition. An ultrafiltration device is selected when the patient has volume overload, pulmonary edema, or interstitial edema, requiring the removal of excess water and small-molecule metabolic waste. A hemoperfusion device is selected when the patient has systemic inflammatory response syndrome, sepsis, acute liver dysfunction, or drug / toxin poisoning, requiring the removal of medium- to large-molecule toxins, inflammatory factors (such as TNF-α, IL-6), endotoxins, bilirubin, or other toxins.

[0034] It should be noted that any blood purification unit with blood purification function, regardless of whether it is an ultrafiltration device, a hemoperfusion device or other type, as long as it is installed on the bypass pipe to form an integral ultrafiltration bypass structure, shall be considered to fall within the protection scope of this application.

[0035] like Figure 2 As shown, the ultrafiltration device mainly consists of an ultrafilter body 4, multiple fiber tubes 8, a distribution chamber 7 located on the inlet side, and a collection chamber 5 located on the outlet side. The distribution chamber 7 is connected to the inlet end of the ultrafilter body 4, and the collection chamber 5 is connected to its outlet end. The multiple fiber tubes 8 are arranged in parallel, with their ends connected to the distribution chamber 7 and the collection chamber 5, respectively, forming a parallel blood pathway. After the blood enters the ultrafilter body 4, it flows through the fiber tubes 8. Through the sieving and convection of the semi-permeable membrane in the fiber tube 8 wall, excess water, small molecule metabolic waste, and electrolytes in the blood are separated out, thereby achieving ultrafiltration therapy.

[0036] To effectively eliminate potential air embolisms within the fiber tube 8, this embodiment includes an exhaust unit at the top of the ultrafilter body 4, controlled by an electronic exhaust valve 6. During normal ultrafiltration operation, the electronic exhaust valve 6 remains closed to maintain the internal sealing and operating pressure of the ultrafilter. Simultaneously, a pressure sensor 9 is installed in the manifold 5 to monitor the outlet pressure in real time.

[0037] When the upper part of the fiber tube 8 is partially blocked due to the accumulation of air emboli, the blood flowing through this area is obstructed, causing a drop in blood pressure within the collection chamber 5. Once the pressure sensor 9 detects that the pressure is below a preset threshold, the control system triggers the electronic exhaust valve 6 to open, allowing the gas accumulated in the upper part of the fiber tube 8 and the top of the ultrafilter to be released, thereby restoring the patency of the fiber tube 8 and the ultrafiltration efficiency.

[0038] like Figure 2As shown, the exhaust device in this embodiment is designed based on the principle of gravity exhaust and mainly consists of an exhaust chamber 11 and an automatic exhaust valve. The exhaust chamber 11 is made of transparent medical material, and a liquid level sensor 10 is installed on its side wall to monitor the liquid level in the chamber in real time. If the liquid level drops below the safety set value, the control system will immediately issue an alarm to remind the operator to intervene.

[0039] During normal system operation, air emboli formed near the liquid outlet of fiber tube 8 can be directly carried into the exhaust chamber 11 by blood flow. After accumulating in the exhaust chamber 11, this gas is discharged through the automatic exhaust valve at the top. The function of the automatic exhaust valve is to ensure effective exhaust of gas in the exhaust chamber 11 while preventing outside air from entering.

[0040] The specific structure of the automatic air vent valve is as follows: Figure 4 As shown, it mainly consists of a gas collecting hood 27, an exhaust pipe 21, a sealing block 22, a connecting rod 23, a float 24, a guide pipe 26, and a pressure balancing pipe 25. The gas collecting hood 27 is a trumpet-shaped structure, fixed to the top of the exhaust chamber 11; the exhaust pipe 21 is connected to the upper side of the gas collecting hood 27, and the two communicate through a connecting hole 28. An exhaust port is provided at the top of the exhaust pipe 21. The guide pipe 26 is vertically installed at the bottom of the exhaust pipe 21, and several orifices are opened on its side wall at a set height. The pressure balancing pipe 25 is L-shaped, with one end connected to the bottom of the exhaust pipe 21 and the other end connected to the atmosphere. An appropriate amount of physiological saline is injected into the exhaust pipe 21 and the pressure balancing pipe 25, keeping the liquid levels at both locations at the same level under normal pressure.

[0041] A float 24 is placed inside a guide tube 26, and its top is connected to a sealing block 22 via a connecting rod 23. Under the buoyancy of the saline solution, the float 24 causes the sealing block 22 to move upward, blocking the exhaust port at the top of the exhaust pipe 21, thus forming a normally closed state. When gas accumulates in the gas collecting hood 27 and the exhaust pipe 21 and forms a certain pressure, this pressure pushes the liquid level in the exhaust pipe 21 down, causing the float 24 to descend accordingly. This, along with the connecting rod 23, causes the sealing block 22 to move downward, thereby opening the exhaust port and achieving automatic venting. After the gas is expelled and the pressure returns to equilibrium, the liquid level rises, the float 24 floats back up, and the sealing block 22 re-closes the exhaust port, restoring the normally closed state.

[0042] The float 24 can also be replaced with other buoyancy elements that meet the requirements, as long as the sealing block 22 and the connecting rod 23 are always aligned along the same vertical axis so that the sealing block 22 can stably and reliably seal the exhaust port of the exhaust pipe 21.

[0043] The liquid level sensor 10 installed on the side wall of the exhaust chamber 11 can be a model suitable for medical transparent tubing, with contact or non-contact detection capabilities, such as a capacitive liquid level sensor 10 (medical grade model), an infrared optical liquid level sensor, or an ultrasonic liquid level sensor. These sensors typically have a detection accuracy of ±1mm, a millisecond-level response speed, and can operate stably in humid and biological liquid environments.

[0044] When the level sensor 10 detects that the blood level is below a preset minimum safety threshold (e.g., below 1 / 3 of the height of the exhaust chamber 11), the control system will simultaneously determine that the fiber tube 8 in the ultrafiltration device may be blocked or that there is an abnormal blood flow, and will then trigger an alarm to alert the operator. At the same time, the control system can automatically reduce the speed of the blood pump 12 to decrease the suction force, or directly stop the blood pump 12 if the abnormality persists, thereby preventing air embolism from being pushed into the downstream pipeline. The level sensor 10 and the pressure sensor 9 at the manifold 5 together form a dual monitoring system, verifying and linking the risk of air embolism from the two dimensions of maintaining the level and stabilizing the pressure, significantly improving the system's reliability in identifying blockage faults and overall safety.

[0045] In this embodiment, the ultrasonic bubble detector 13 can be a medical ultrasonic Doppler bubble detection sensor with high sensitivity and real-time response characteristics. The detector is placed between the blood pump 12 and the three-way valve 14, forming the last safety barrier of the entire ultrafiltration bypass structure.

[0046] The bypass pipe 3 is connected in sequence to the fixed end and one of the reversing ends of the three-way valve 14, and the other reversing end of the three-way valve 14 is connected to the isolation and blocking unit. In this embodiment, the isolation and blocking unit is a disposable medical isolation bag 15.

[0047] When blood from the blood pump 12 flows through the ultrasonic bubble detector 13, if bubbles are still detected, the control system will immediately drive the three-way valve 14 to switch the flow path, diverting the current blood flow from the bypass tube 3 into the isolation bag 15, and simultaneously triggering an audible and visual alarm to prompt the operator to intervene. This mechanism ensures that any blood containing bubbles is effectively intercepted, completely blocking its possibility of entering the ECMO main circulation, thus providing ultimate safety for the patient even in extreme circumstances.

[0048] This embodiment also provides a method for safety monitoring of detachable ultrafiltration bypass emboli in ECMO tubing, the specific method of which is as follows: S1: System pre-charge and initial exhaust (1) Connect the sealing disassembly connector at the inlet end of the bypass pipe to the arterial end tee connector of the ECMO main circulation pipeline. During the connection process, screw the rotating connector into the sealing nut, and its push rod opens the sealing plate, automatically connecting the pipeline while establishing a seal.

[0049] (2) Start the blood pump and adjust the three-way valve through the controller to open the bypass tube. At this time, the system enters the pre-fill mode, and blood is introduced from the ECMO main circulation, flowing through the bypass tube to the sealing and disassembly connector at the outlet. (This state fully utilizes the aforementioned structural design: under the pressure corresponding to the blood flow rate (100-300 mL / min), the spring can ensure that the sealing plate remains reliably closed).

[0050] This stage utilizes the automatic exhaust valve of the exhaust device and the electronic exhaust valve at the top of the ultrafiltration device to initially exhaust the residual gas in the pipeline and filter, and uses the structure of the sealed disassembly joint to allow the pre-filled blood to expel the air from the joint.

[0051] S2: Piping Setup and Safety Verification (1) After S1 is completed, pre-install the sealing disassembly connector of the bypass pipe outlet end on the corresponding tee connector of the ECMO main circulation circuit, then screw the rotary connector into the sealing nut and reach the maximum stroke position, and push the push rod to open the sealing plate so that the bypass pipe is connected to the ECMO main circuit.

[0052] (2) Keep the blood pump running. Blood enters from the connected inlet and flows through the entire bypass pipeline (ultrafiltration device, exhaust device, etc.).

[0053] During this process, the system utilizes the automatic venting valve, pressure sensor, and liquid level sensor of the venting device to ensure that there is no residual gas in the entire bypass pipeline and components before reaching the liquid outlet. An ultrasonic bubble detector continuously monitors this stage as final confirmation of the absence of gas.

[0054] S3: Operational detection and active exhaust During this phase, the control system enters a continuous monitoring state, forming a three-layer progressive safety protection.

[0055] First layer: Early warning and active venting based on dual pressure and liquid level sensing. A pressure sensor located in the ultrafiltration unit's manifold monitors the outlet pressure in real time. A liquid level sensor located on the side wall of the exhaust chamber monitors the liquid level in the chamber in real time. The control system responds to pressure signals. and liquid level signal Analyze and verify.

[0056] When pressure decreases first Continued to decline and below the threshold When H remains stable or decreases slowly, the system prioritizes identifying an air embolism in the upper part of the fiber optic tube, leading to increased flow resistance. The controller immediately initiates active venting, opening the electronic vent valve at the top of the ultrafiltration device, and simultaneously adjusts the blood pump speed to attempt to clear the blockage.

[0057] When the liquid level drops first Rapidly drop to a safe threshold sometimes If the change is delayed or insignificant, the system will prioritize identifying an abnormal suction in the downstream pipeline or return end, or a large amount of gas embolism entering the exhaust chamber. The controller will immediately trigger an advanced alarm and take protective measures, such as reducing or suspending the blood pump.

[0058] When the pressure and liquid level are not synchronized, the control system determines that there is a serious blockage or a large-scale air embolism, immediately activates the highest level alarm, opens all exhaust paths, and significantly reduces the blood pump flow.

[0059] By combining and analyzing pressure and liquid level data, the system can more accurately determine the location, size, and development trend of air embolisms, achieving an advancement from "single alarm" to "intelligent diagnosis".

[0060] The second layer: Regardless of whether the system issues an active exhaust command, the automatic exhaust valve (float valve) at the top of the exhaust chamber is always in working condition. It opens and closes autonomously according to the air pressure inside the exhaust chamber, continuously expelling free air bubbles flowing in with the blood and gases discharged from the ultrafiltration device, serving as a passive safety barrier that requires no external power.

[0061] The third layer: The ultrasonic bubble detector serves as the last and most sensitive line of defense, constantly monitoring the blood about to enter the main circulation. If a bubble is detected at any time, the control system will immediately activate the three-way valve within milliseconds, redirecting the blood flow back to the isolation bag and triggering an audible and visual alarm.

[0062] This method constructs a closed-loop system for full-cycle, fully automated air embolism safety monitoring and handling, from pipeline connection to stable treatment operation, which greatly improves the reliability and safety of ECMO-ultrafiltration combined therapy.

[0063] Example 2: A detachable ultrafiltration bypass structure for ECMO tubing. Compared to Example 1, this example provides a new top-opening valve core in the sealed disassembly joint. Specifically, as follows... Figure 6 As shown, the top-opening valve core is a duckbill valve 29, which is fixedly installed at the through hole of the sealing nut 18.

[0064] When only the sealing nut 18 is installed on the side port of the T-connector 2 in the ECMO main circuit, the duckbill valve 29 is in a naturally closed state, acting as a one-way valve to effectively prevent blood in the main circuit from flowing out through the side port of the T-connector 2. When it is necessary to connect the bypass line 3, the rotary connector 17 is installed on the sealing nut 18 and tightened. The end of the rotary connector 17 will mechanically open the duckbill valve 29, thereby establishing a blood flow channel between the bypass line 3 and the T-connector 2.

[0065] The duckbill valve 29 will not be opened by the blood pressure generated in the working flow rate range (100-300 mL / min) of the bypass pipe 3, thus ensuring the operational safety and controllability of the system during the pre-filling and initial venting stages.

[0066] Replacing the mechanical linkage valve core in Example 1 with a duckbill valve 29 not only greatly simplifies the structure and reduces the number of parts, thus lowering processing and assembly costs, but also improves fluid performance. The flow channel shape after the duckbill valve 29 is opened can effectively reduce the local resistance loss when blood flows through this area, which is conducive to the smooth flow of blood into the bypass pipe 3.

[0067] It should be noted that regardless of the structure of the sealing and disassembly joint, as long as the sealing and disassembly joint design can achieve the core function of "automatic connection during installation and automatic sealing during disassembly", it should be considered to fall within the scope of protection of this application, no matter how its specific structure is modified or improved.

[0068] Example 3: A detachable ultrafiltration bypass structure for ECMO tubing. Compared with Example 1, this example provides a new backflow blocking unit. Figure 7 As shown, the backflow blocking unit in this embodiment is a backflow pipe 30. One end of the backflow pipe 30 is connected to a reversing end of the three-way valve 14, and the other end is connected to the vicinity of the inlet of the bypass pipe 3, thereby forming a closed-loop reprocessing pipeline.

[0069] When the ultrasonic bubble detector 13 detects the presence of air bubbles in the blood flowing out of the ultrafiltration bypass, the control system immediately activates the three-way valve 14 to switch the flow path. At this point, the blood containing air bubbles no longer flows into the ECMO main circulation, but instead returns via the return tube 30 to the inlet of the bypass tube 3, reflowing through the ultrafiltration unit and the venting device for secondary filtration and venting. This process repeats automatically until the gas in the blood is completely removed. Only after the ultrasonic bubble detector 13 confirms the absence of air bubbles will the system switch the three-way valve 14 again, allowing the purified blood to safely return to the main circulation.

[0070] Compared to Embodiment 1, the backflow blocking unit design in this embodiment enables online, automatic, and closed-loop reprocessing of blood containing air bubbles. It eliminates the need for operators to manually replace or dispose of the isolation bag 15, significantly improving the automation and response speed of emergency treatment and preventing blood waste, thus providing dual protection for treatment safety.

[0071] It should be noted that regardless of the structure of the reflux blocking unit, as long as the reflux blocking unit design can achieve the core function of automatically preventing gas-containing blood from returning to the ECMO main circulation when air bubbles are detected, it should be considered to fall within the protection scope defined by the claims of this application.

[0072] Example 4: A detachable ultrafiltration bypass structure for ECMO tubing. Compared to Example 1, this example differs in the structure of the top venting unit, the pressure sensing unit at the liquid outlet, and the automatic venting valve of the venting device. These three structures form a linked, purely mechanical-hydraulic drive system. Specifically... Figure 8 and Figure 9 As shown.

[0073] The exhaust unit at the top of the ultrafiltration device mainly consists of a gas collection hood 31 and an air guide pipe 32. The gas collection hood 31 surrounds the liquid inlet area installed at the top of the ultrafiltration body 4; one end of the air guide pipe 32 is connected to the side wall of the gas collection hood 31, and the other end extends into the exhaust port 37 at the top of the exhaust device.

[0074] The pressure sensing unit at the outlet of the ultrafiltration device mainly consists of an L-shaped hydraulic transmission chamber 33 and two differential pressure sensing pistons 34. One end of the hydraulic transmission chamber 33 is connected to the collection chamber 5 of the ultrafiltration device; the two pistons are slidably disposed in the horizontal and vertical sections of the chamber, respectively, with the chamber between them filled with transmission fluid, forming a closed hydraulic system. The bottom of the differential pressure sensing piston 34 located in the vertical section is connected to the automatic exhaust valve of the exhaust device.

[0075] The automatic exhaust valve mainly consists of a connecting rod 35 and an exhaust valve plate 36. The top end of the connecting rod 35 is connected to the aforementioned vertical piston, and the bottom end is fixed to the exhaust valve plate 36. During normal operation, the pressure in the collecting chamber 5 is stable, the two pistons are in their initial positions, and the exhaust valve plate 36 is tightly fitted under the action of the connecting rod 35, sealing the exhaust port 37 of the exhaust device and simultaneously blocking the air guide pipe 32.

[0076] When air embolisms form in the fiber tubes 8 inside the ultrafiltration device, causing blockage, the outlet pressure of the collecting chamber 5 decreases. This pressure change drives the piston in the horizontal section to move towards the collecting chamber 5, and through the transmission fluid within the chamber, pushes the piston in the vertical section upward. The piston in the vertical section pulls the connecting rod 35 upward, thereby lifting the exhaust valve plate 36. This exhaust valve plate 36 opens the exhaust port 37 of the exhaust device on one hand, and connects the outlet of the air guide tube 32 with the interior of the exhaust device on the other hand, forming a suction passage.

[0077] Therefore, the air plugs near the liquid outlet of the fiber tube 8 can flow into the exhaust device with the blood and be discharged through the exhaust hole 37; while the air plugs accumulated in the upper part and top of the fiber tube 8 can be collected by the gas collection hood 31 under the action of pressure difference, and actively drawn into the exhaust device through the air guide tube 32 and discharged together.

[0078] This embodiment achieves simultaneous dual-path exhaust via hydraulic-mechanical linkage using a single pressure signal. This design can completely expel air clogging at different locations (top, middle, and outlet) within the fiber tube 8 of the ultrafiltration device, significantly improving exhaust efficiency and reliability. The entire triggering and execution process is based entirely on mechanical and fluid principles, requiring no electronic sensors for motion control, reducing the use of electronic components and simplifying the system control logic.

[0079] Example 5: Detachable ultrafiltration bypass structure for ECMO tubing. The main difference between this example and Example 1 is the type and installation location of the venting device, which aims to prevent air bubbles from entering the ultrafiltration device at the source.

[0080] like Figure 10 and Figure 11 As shown, this embodiment uses a hydrocyclone 38 as an exhaust device, and by placing it upstream of the ultrafiltration device along with the blood pump 12, active separation and preventative removal of gas are achieved. The top of the hydrocyclone 38 is equipped with the same automatic exhaust valve as in Embodiment 1. Blood introduced from the ECMO main circuit is first pressurized by blood pump 12 and then injected tangentially into the inlet of hydrocyclone 38. The blood rotates at high speed within the swirling chamber of hydrocyclone 38. Under centrifugal force, lower density air bubbles gather and rise to the top of the hydrocyclone 38's central axis. The gas that rises to the top is discharged through an automatic vent valve. The degassed blood then flows out from the outlet at the bottom of hydrocyclone 38 and enters the downstream ultrafiltration unit.

[0081] By actively degassing the blood before the ultrafiltration unit, the air bubble content in the blood entering the fiber tube 8 of the ultrafiltration unit can be significantly reduced, effectively preventing blockage caused by air bubbles accumulating and coalescing within the fiber tube 8. This solution shifts the exhaust strategy from "post-treatment" to "pre-treatment," reducing the pressure on the ultrafiltration unit's own exhaust unit and improving the safety and stability of the entire bypass system.

[0082] Example 6: A detachable ultrafiltration bypass structure for ECMO tubing, such as... Figure 12 As shown, compared with Embodiment 1, a hemoperfusion device is connected in series upstream of the ultrafiltration device in this embodiment. The hemoperfusion device is installed upstream of the ultrafiltration device, and its inlet is connected to the bypass pipe, and its outlet is connected to the distribution chamber of the ultrafiltration device, so that blood flows through the hemoperfusion device and the ultrafiltration device in sequence.

[0083] The hemoperfusion device is filled with biocompatible adsorption resin or activated carbon to adsorb and remove medium and large molecular toxins, inflammatory factors, drugs, and poisons from the blood. After purification by the hemoperfusion device, the blood then enters an ultrafiltration device for volume control, where excess water and small molecular metabolic waste are removed through the semi-permeable membrane of fiber tube 8.

[0084] This embodiment connects a hemoperfusion device and an ultrafiltration device in series, achieving targeted removal of medium and large molecular pathogens and precise management of body fluid volume, respectively. It can provide an integrated blood purification solution for common clinical scenarios in ECMO treatment, such as systemic inflammatory response syndrome, sepsis, acute liver dysfunction, and drug poisoning.

[0085] It should be noted that this embodiment is merely an exemplary implementation for extending the functionality of the present invention, and its purpose is to further expand the clinical application scope of the detachable ultrafiltration bypass structure. Based on this, any implementation that adds functional components to the basic ultrafiltration bypass structure provided by the present invention to expand application scenarios should be considered to fall within the protection scope of this application. The above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A detachable ultrafiltration bypass structure for ECMO tubing, characterized in that, Includes a bypass pipe (3) and two sealing disassembly joints. The two sealing disassembly joints are installed on the inlet and outlet ends of the bypass pipe (3) and can be installed on the two T-joints (2) of the ECMO pipeline respectively. A blood purification unit, an exhaust device, a blood pump (12), and a three-way valve (14) are connected in series on the bypass pipe (3); the common end and one of the reversing ends of the three-way valve (14) are installed on the bypass pipe (3), and the other reversing end of the three-way valve (14) is provided with a backflow blocking unit. A bubble detector is provided upstream of the backflow blocking unit on the bypass pipe (3). When the bubble detector detects bubbles in the blood, the three-way valve (14) reverses, allowing the blood to flow into the backflow blocking unit and preventing the blood from flowing back into the ECMO main circulation pipe. The blood purification unit is used to purify blood. The outlet and inlet of the blood purification unit are detachably installed on the bypass pipe (3). An automatic exhaust valve is installed on the top of the exhaust device.

2. The detachable ultrafiltration bypass structure for ECMO tubing according to claim 1, characterized in that, The sealing disassembly joint includes a rotary joint (17), a sealing nut (18), and a top-opening valve core; the rotary joint (17) is sealed and rotatably connected to the bypass pipe (3); the sealing nut (18) has a through hole, and its through hole position is detachably connected to the rotary joint (17); the top-opening valve core can communicate after the rotary joint (17) and the sealing nut (18) are connected, and can automatically close the through hole of the sealing nut (18) after separation.

3. The detachable ultrafiltration bypass structure for ECMO tubing according to claim 2, characterized in that, The top-opening valve core includes a push rod (19), a sealing plate (20), and a spring (16); the push rod (19) is horizontally installed at the end of the rotary joint (17); the fixed end of the spring (16) is installed in the sealing nut (18), and the free end of the spring (16) is fixedly connected to the sealing plate (20). In its natural state, the sealing plate (20) is blocked by the tension of the spring (16) and the through hole of the sealing nut (18).

4. The detachable ultrafiltration bypass structure for ECMO tubing according to claim 3, characterized in that, The top-opening valve core is a duckbill valve (29). The duckbill valve (29) is fixedly installed at the through hole of the sealing nut (18). When the rotary joint (17) is rotated and fixedly installed on the sealing nut (18), the duckbill valve (29) can be opened to achieve communication with the three-way joint (2).

5. The detachable ultrafiltration bypass structure for ECMO tubing according to claim 1, characterized in that, The backflow blocking unit is a backflow pipe (30). One end of the backflow pipe (30) is connected to the reversing end of the three-way valve (14), and the other end is connected to the liquid inlet of the bypass pipe (3).

6. The detachable ultrafiltration bypass structure for ECMO tubing according to claim 1, characterized in that, The blood purification unit is an ultrafiltration device. The outlet end of the ultrafiltration device is equipped with a pressure sensing unit, and the top of the ultrafiltration device is equipped with an exhaust unit. The pressure sensing unit includes a hydraulic transmission chamber (33) and two differential pressure sensing pistons (34). The hydraulic transmission chamber (33) is connected to the outlet end of the ultrafiltration device. The two differential pressure sensing pistons (34) are slidably disposed in the hydraulic transmission chamber (33). A sealed cavity is formed between the two differential pressure sensing pistons (34), and the sealed cavity is filled with transmission fluid.

7. The detachable ultrafiltration bypass structure for ECMO tubing according to claim 6, characterized in that, The automatic exhaust valve includes a connecting rod (35) and an exhaust valve plate (36). The two ends of the connecting rod (35) are connected to the exhaust valve plate (36) and the differential pressure sensing piston (34) respectively. The exhaust valve plate (36) is attached to the exhaust hole (37) on the top of the exhaust device and blocks the exhaust hole (37). When the pressure at the outlet of the ultrafiltration device decreases, the exhaust valve plate (36) can be pulled under the action of negative pressure to open the exhaust hole (37) of the exhaust device.

8. The detachable ultrafiltration bypass structure for ECMO tubing according to claim 7, characterized in that, The exhaust unit includes a duct (32) and a second gas collection hood (31). The second gas collection hood (31) is fixedly installed on the top of the ultrafiltration device. The side wall of the second gas collection hood (31) is connected to the duct (32). The end of the duct (32) away from the second gas collection hood (31) is located on the exhaust hole (37) on the top of the exhaust device. When the exhaust valve plate (36) is in contact with the top surface of the exhaust device, it simultaneously seals the duct (32).

9. The detachable ultrafiltration bypass structure for ECMO tubing according to claim 6, characterized in that, The automatic exhaust valve includes a gas collection hood (27), an exhaust pipe (21), a sealed container, a connecting rod (23), a float (24), a guide pipe (26), and an L-shaped pressure balance pipe (25). The side wall of the gas collection hood (27) is connected to the exhaust pipe (21), and the guide pipe (26) is fixed to the bottom of the exhaust pipe (21), and its side wall is provided with several orifices. One end of the pressure balance pipe (25) is connected to the bottom of the exhaust pipe (21), and the pressure balance pipe (25) and the exhaust pipe (21) are filled with liquid. The float (24) is located in the guide pipe (26) and can float with the rise and fall of the liquid level.

10. A method for safety monitoring of a detachable ultrafiltration bypass vent in an ECMO tubing, characterized in that, This method is applied to the ultrafiltration bypass structure of any one of claims 6-9; the specific method is as follows: S1: System pre-filling and initial venting. Connect the sealing and disassembly connector of the bypass tube inlet end to the three-way connector of the ECMO main circulation line, start the blood pump, and adjust the three-way valve through the controller to connect the bypass tube to the reflux blocking unit. S2: Connection confirmation and pipeline establishment. When the bubble detector detects no bubbles in the flowing blood, the controller adjusts the three-way valve to form a connecting pipeline through the bypass pipe, and the blood flows to the outlet end through the bypass pipe. Connect the sealing and disassembly connector at the outlet end to the corresponding three-way connector of the ECMO main circulation pipeline to complete the system pre-filling and initial venting. S3: Operation monitoring and active venting. During continuous operation, the pressure sensing unit monitors the pressure at the outlet of the ultrafiltration device in real time. When the pressure value drops to the system's set threshold, the controller determines that an air embolism has occurred in the fiber tube inside the ultrafiltration device and controls the venting unit to open. At the same time, the bubble detector monitors the blood about to flow back into the ECMO main circulation tubing in real time. If a bubble is detected, the controller immediately switches the flow path of the three-way valve and triggers an alarm, allowing the blood containing the bubble to flow into the backflow blocking unit to prevent it from entering the patient's circulation.

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