A dual-loop circulation system for ex vivo drainage testing of extracorporeal membrane oxygenation (ECMO) venous drainage tubes

Abstract

This invention relates to a dual-loop circulation system for in vitro drainage testing of extracorporeal membrane oxygenation (ECMO) venous drainage tubes, belonging to the field of medical engineering technology. The invention utilizes a blood circulation simulation module to accurately simulate the blood flow waveform of the inferior vena cava under physiological or pathological conditions, while a venous drainage module effectively simulates the drainage effect of ECMO venous drainage for evaluation. The dual-loop system of this invention investigates the influence of different drainage methods on drainage efficiency and venous apposition issues by replacing rigid / elastic venous simulation tubes. This provides a more scientific and effective in vitro testing and evaluation platform for effectively assessing the hydrodynamic performance of venous drainage tubes when the drainage orifice is blocked, thereby improving the drainage efficiency of venous drainage tubes.

Description

Technical Field

[0001] This invention belongs to the field of medical engineering technology and relates to a dual-loop circulation system for ex vivo drainage testing of extracorporeal membrane oxygenation (ECMO) venous drainage tubes. It is an ex vivo testing and evaluation system for venous drainage tube drainage hole wall blockage designed based on hemodynamic principles, clinical operation simulation, signal monitoring technology and automatic control technology. Background Technology

[0002] Extracorporeal membrane oxygenation (ECMO), also known as extracorporeal artificial heart and lung, is a critical care emergency treatment technique that supports the breathing and circulation of patients with severe cardiopulmonary failure through an extracorporeal circulation device.

[0003] ECMO works by drawing blood from the patient's body through a venous drainage tube, pumping it through a centrifugal pump into an external oxygenator, and then returning it to the patient through an arterial cannula. A significant challenge encountered in ECMO blood draw is the blockage of the venous drainage tube's drainage hole by adhesion to the wall, leading to tube tremors. Deformation and movement of the vein wall cause unstable tremors in the cannula, further obstructing the drainage tube and significantly reducing blood flow. This can disrupt treatment and even pose a serious risk of ischemia and hypoxia to other organs, severely impacting the patient's life. The main reason for venous drainage tube blockage is the softness of the vein walls. Under insufficient volume or high negative pressure, the vein walls can collapse, encasing the drainage tube and blocking the drainage hole, thus affecting drainage efficiency.

[0004] When using real animal models for in vivo experiments, rigorous surgical procedures are required, including establishing drainage pathways and administering appropriate anesthesia and analgesia to ensure animal safety and prevent complications such as thrombosis or bleeding. In vitro testing offers more flexible control, improving experimental controllability and reproducibility. Compared to in vivo experiments, it saves time, reduces costs, and mitigates potential ethical and safety risks. Early in vitro testing systems using pulsatile blood pumps failed to meet the high flow requirements of ECMO. Furthermore, current in vitro fluid dynamics models used to test venous drainage tube performance place the tube within a testing container, using a single rigid simulation tube. This fails to assess the impact of different insertion types and drainage methods on anti-apoptosis function. The testing container cannot simulate the blood flow in the inferior vena cava, and therefore cannot accurately simulate the real in vivo environment, failing to reflect clinical cases of venous drainage tube apoptosis and blockage, and thus cannot effectively assess the fluid dynamics of venous drainage tube blockage. Therefore, there is an urgent need for an in vitro circulation testing system that can simulate the in vivo blood flow and circulation process and the drainage process of venous drainage tubes.

[0005] This invention constructs an ex vivo blood circulation system that can accurately and realistically simulate the blood flow environment of the inferior vena cava in vivo. Combined with an elastic tube material that simulates vascular mechanics, the drainage efficiency of the venous drainage tube is evaluated in vitro under different blood flow conditions. This has significant clinical significance and practical value for improving the venous drainage efficiency of ECMO, optimizing venous drainage tube design, and improving clinical surgical procedures. Summary of the Invention

[0006] The purpose of this invention is to design and construct a dual-loop circulation system for in vitro drainage testing of extracorporeal membrane oxygenation (ECMO) venous drainage tubes. This system can simulate both the blood flow and circulation of the inferior vena cava in vitro and the drainage process of the venous drainage tube. Furthermore, a rigid venous simulation tube is used to conduct drainage experiments, testing the influence of the venous drainage tube and drainage method on drainage efficiency. A venous simulation tube with in vivo venous elasticity characteristics is also used to conduct drainage experiments, testing the influence of the venous drainage tube and drainage method on drainage efficiency and anti-adhesion function.

[0007] The technical solution of the present invention is as follows:

[0008] A dual-loop circulation system for ex vivo drainage testing of extracorporeal membrane oxygenation (ECMO) venous drainage tubes includes a blood circulation simulation module and a venous drainage circulation module.

[0009] The blood circulation simulation module includes: a blood circulation loop L B And a blood flow control loading and signal detection unit. The blood circulation loop L... BIt includes: a first programmable flow pump A-1, a Y-type three-way tube A-2, an inferior vena cava simulation tube A-3, a storage bottle A-4, and a lifting platform A-5. The first programmable flow pump A-1 drives the solution in the storage bottle A-4, which is fixed on the lifting platform A-5, through flow waveform programming control. The solution is pumped through the conduit into the first inlet of the Y-type three-way tube A-2, flows through the inferior vena cava simulation tube A-3, and finally flows back to the storage bottle A-4. The inferior vena cava simulation tube A-3 is made of different materials and has different rigidities depending on the size, shape, and testing conditions of the human inferior vena cava. The liquid storage bottle A-4 is fixed on the lifting platform A-5, which is higher than the common horizontal plane of the first programmable flow pump A-1, the Y-type three-way tube A-2, and the inferior vena cava simulation tube A-3. The lifting platform A-5 can adjust the vertical height h of the liquid storage bottle A-4. Using Pascal's law p = ρgh, the basic pressure value p is provided by adjusting the height h to simulate the basic pressure of the inferior vena cava, where ρ represents the solution density and g represents the acceleration due to gravity.

[0010] The blood flow control loading and signal detection unit ( Figure 2 The system includes: a main control host computer C-1, a first microcontroller and drive module C-2, a DC power supply C-3, and a first flow sensor C-4. The first microcontroller and drive module C-2 consists of a microcontroller and a motor drive module. The main control host computer C-1 inputs commands to the microcontroller in the first microcontroller and drive module C-2 via a communication cable. The first flow sensor C-4 is located at the outlet pipe of the first programmable flow pump A-1. It converts the flow information into velocity information using the formula: Flow velocity V = Flow rate Q / Pipe diameter / Cross-sectional area S, and then transmits this information back to the main control host computer C-1 via the communication cable through the microcontroller in the first microcontroller and drive module C-2. The DC power supply C-3 provides a stable power signal to the motor drive module in the first microcontroller and drive module C-2, which, after being applied by the motor drive module, is applied to the first programmable flow pump A-1 to generate stable motor torque and speed. Furthermore, the blood flow control loading and signal detection unit adopts a proportional-integral-derivative control method. The first flow sensor C-4 transmits the flow velocity information back to the microcontroller in the first microcontroller and the driver module C-2. The microcontroller continuously fits the measured flow velocity information with the simulated waveform of the human inferior vena cava, and outputs a continuously corrected pulse width modulation signal. This signal is then loaded onto the first programmable flow pump A-1 by the driver module to accurately output the set flow velocity waveform.

[0011] The aforementioned venous drainage circulation module includes: a venous drainage circulation loop L D Drainage control and signal detection unit. The described venous drainage circulation loop L... DThis includes: a second programmable flow pump B-1 and a venous drainage tube B-2. The second programmable flow pump B-1, through flow waveform programming control, draws the solution from the venous drainage tube B-2, which is located in the inferior vena cava simulation tube A-3 and extends to the second inlet of the Y-shaped three-way tube A-2, from the inferior vena cava simulation tube A-3, and connects it through a catheter to a storage bottle A-4 fixed on a lifting platform A-5. Furthermore, the venous drainage tube B-2 employs clinically available venous drainage tubes with different structural parameters such as the number of side holes, the level of side holes, and the spatial distribution of side holes, to test the drainage efficiency and wall adhesion phenomenon of different venous drainage tubes.

[0012] The drainage control and signal detection unit ( Figure 2 This includes: a second microcontroller and drive module D-1, a second flow sensor D-2, a wireless pressure sensor D-3, and a wireless flow sensor D-4. The second microcontroller and drive module D-1 consists of a microcontroller and a motor drive module. The host computer C-1 inputs commands to the microcontroller in the second microcontroller and drive module D-1 via a communication cable. The second flow sensor D-2 is located at the outlet of the venous drainage tube B-2. It converts the flow information into velocity information using the formula: Flow velocity V = Flow rate Q / Pipe diameter / Cross-sectional area S, and then transmits this information back to the host computer C-1 via the communication cable. The wireless pressure sensor D-3, wireless... Flow sensor D-4 is installed at the portion of the inferior vena cava simulation tube A-3 of the venous drainage tube B-2. It transmits the drainage velocity and pressure information at the venous drainage tube B-2 in real time back to the main control computer C-1. Changes in drainage velocity and pressure reflect drainage efficiency and adhesion to the wall. DC power supply C-3 provides a stable power signal to the motor drive module in the second microcontroller and drive module D-1. After being processed by the motor drive module, the signal is applied to the second programmable flow pump B-1 to generate stable motor torque and speed. Furthermore, the drainage control and signal detection unit adopts a proportional-integral-derivative control method. The second flow sensor D-2 transmits the flow velocity information back to the microcontroller in the second microcontroller and drive module D-1. The microcontroller continuously fits the measured flow velocity information with the input venous drainage waveform, outputting a continuously corrected pulse width modulation signal. This signal is then applied to the second programmable flow pump B-1 to accurately output the set flow velocity waveform.

[0013] Furthermore, the selection of the inferior vena cava simulation tube A-3 is as follows: an elastic flexible tube with the same mechanical properties as the human inferior vena cava is used to test the drainage efficiency and wall adhesion during the drainage process; a transparent rigid tube is used to eliminate the influence of wall adhesion during the drainage process and to test the drainage efficiency separately.

[0014] Furthermore, using a dual-loop circulation system with the above-described structure for ex vivo extracorporeal membrane oxygenation (ECMO) venous drainage tube testing, we investigated the effects of venous drainage tube structure and drainage method on drainage efficiency and venous apposition to the wall. The experimental steps are as follows:

[0015] Step 1: Inferior vena cava simulation tube A-3. A rigid tube was used to conduct a venous drainage experiment under different pressure conditions to test the effect of venous drainage tube structure and drainage method on drainage efficiency.

[0016] Step 2: Using a venous simulation tube with in vivo venous elasticity characteristics, conduct venous drainage experiments under different pressure conditions to test the effects of venous drainage tube structure and drainage method on drainage efficiency and anti-adhesion function.

[0017] The beneficial effects of this invention are as follows: The blood circulation simulation module accurately simulates the blood flow waveform of the inferior vena cava under physiological or pathological conditions, while the venous drainage module provides a stable and continuous drainage effect. This invention's dual-circulation system, by replacing rigid / elastic venous simulation tubes, explores the influence of the drainage method on drainage efficiency and venous apposition. It provides a more scientific and effective in vitro testing and evaluation platform for effectively evaluating the hydrodynamic performance of venous drainage tubes when the drainage orifice is blocked, thereby improving the drainage efficiency of venous drainage tubes. Attached Figure Description

[0018] Figure 1 This is a structural diagram of the blood circulation simulation module and the venous drainage circulation module; L B It is the blood circulation circuit; L D It is a venous drainage circulation loop.

[0019] Figure 2 This is a structural diagram of the dual-loop circulatory system used in the extracorporeal membrane oxygenation (ECMO) venous drainage test.

[0020] In the diagram: A-1 is programmable flow pump 1, A-2 is a Y-type three-way tube, A-3 is an inferior vena cava simulation tube, A-4 is a storage bottle, A-5 is a lifting platform, B-1 is programmable flow pump 2, B-2 is a venous drainage tube, C-1 is the main control host computer, C-2 is a microcontroller and driver module 1, C-3 is a DC power supply, C-4 is a flow sensor 1, D-1 is a microcontroller and driver module 2, D-2 is a flow sensor 2, D-3 is a wireless pressure sensor, and D-4 is a wireless flow sensor. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0022] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0023] The specific configuration is determined according to actual construction requirements, and no specific restrictions are imposed in this application. A dual-loop circulation system for ex vivo drainage testing of extracorporeal membrane oxygenation (ECMO) venous drainage tubes is characterized by: a blood circulation loop and a venous drainage circulation module. The blood circulation loop (I) includes: a first programmable flow pump A-1, a Y-type three-way tube A-2, an inferior vena cava simulation tube A-3, a storage bottle A-4, a lifting platform A-5, a main control host computer C-1, a first microcontroller and drive module C-2, a DC power supply C-3, and a first flow sensor C-4. The venous drainage module includes: a second programmable flow pump B-1, a venous drainage tube B-2, a second microcontroller and drive module D-1, a second flow sensor D-2, a wireless pressure sensor D-3, and a wireless flow sensor D-4. Before the drainage test begins, the device is configured as follows... Figure 1 , Figure 2 The connection is shown.

[0024] The working process of the dual-circulation system is as follows:

[0025] The host computer C-1 is connected to the microcontrollers in the first microcontroller and driver module C-2 and the second microcontroller and driver module D-1 for parameter setting and data transmission. The DC power supply C-3 is connected to the driver modules in the first microcontroller and driver module C-2 and the second microcontroller and driver module D-1 to power the first programmable flow pump A-1 and the second programmable flow pump B-1. Adjusting the height of the storage bottle A-4 on the lifting platform A-5 simulates the baseline pressure of the inferior vena cava. The driver module in the first microcontroller and driver module C-2 is connected to the first programmable flow pump A-1 via a communication cable. The first programmable flow pump A-1 is driven to output a waveform simulating blood flow in the inferior vena cava. The inlet of the first programmable flow pump A-1 is connected to the outlet of the storage bottle A-4 through a conduit, and the outlet of the first programmable flow pump A-1 is connected to the first inlet of the Y-type three-way tube A-2 through a conduit. The first flow sensor C-4 is set at the outlet of the first programmable flow pump A-1 and is connected to the microcontroller in the first microcontroller and the microcontroller in the drive module C-2 through a communication wire. One end of the inferior vena cava simulation tube A-3 is connected to the outlet of the Y-type three-way tube A-2, and the other end is introduced into the storage bottle A-4 fixed on the lifting platform A-5 through a conduit.

[0026] The second microcontroller is connected to the second programmable flow pump B-1 via a communication cable, driving the second programmable flow pump B-1 to output the waveform of venous drainage. One end of the venous drainage tube B-2 enters from the second inlet of the Y-type three-way tube A-2 and extends to a certain depth (adjustable depth) of the inferior vena cava simulation tube A-3. The other end is connected to the inlet of the second programmable flow pump B-1 via a conduit. The second flow sensor D-2 is located at the drainage outlet of the venous drainage tube B-2 and is connected to the microcontroller in the second microcontroller and the driver module D-1 via a communication cable. The outlet of the second programmable flow pump B-1 is introduced into the storage bottle A-4 fixed on the lifting platform A-5 via a conduit. The wireless pressure sensor D-3 and the wireless flow sensor D-4 are located on the part of the venous drainage tube B-2 extending to the inferior vena cava simulation tube A-3, and are used to monitor the real-time drainage flow rate and tube wall pressure.

[0027] Once the device is set up, testing experiments can be conducted. For different situations, the inferior vena cava simulation tube A-3 can be replaced with a rigid tube and an elastic flexible tube with in vivo venous elasticity characteristics. Using the rigid tube, drainage experiments can be conducted under different pressure conditions to test the impact of the venous drainage tube structure and drainage method on drainage efficiency. Using the elastic flexible tube with in vivo venous elasticity characteristics, drainage experiments can be conducted under different pressure conditions to test the impact of the venous drainage tube structure and drainage method on drainage efficiency and anti-adhesion function.

[0028] The procedure for completing the ex vivo venous drainage test is as follows:

[0029] Step 1: Pre-treatment, installing the inferior vena cava simulation tube A-3 as a rigid tube.

[0030] Step 2: Turn on the DC power supply C-3, and set the required inferior vena cava simulation waveform parameters and the drainage waveform parameters of the venous drainage tube B-2 on the main control computer C-1.

[0031] Step 3: Press the machine switch to start the experiment. Observe the drainage velocity and pressure values ​​of the venous drainage tube B-2, which are transmitted back by the wireless pressure sensor D-3 and the wireless flow sensor D-4, as displayed on the main control computer C-1. Change the venous drainage velocity and record the flow rate drawn out by the venous drainage tube per unit time under the corresponding conditions to calculate the drainage efficiency.

[0032] Step 4: Turn off the machine. The rigid tube experiment is now complete.

[0033] Step 5: Pre-processing. Replace the inferior vena cava simulation tube A-3 with an elastic tube that has the characteristic parameters of the human inferior vena cava.

[0034] Step 6: Turn on the DC power supply C-3, and set the required inferior vena cava simulation waveform parameters and the drainage waveform parameters of the venous drainage tube B-2 on the main control computer C-1.

[0035] Step 7: By observing the drainage velocity and pressure values ​​of the venous drainage tube B-2 as transmitted back by the wireless pressure sensor D-3 and the wireless flow sensor D-4, as displayed on the main control computer C-1, change the venous drainage velocity, observe whether the phenomenon of adhesion to the wall occurs, and record the flow rate of the venous drainage tube per unit time under the corresponding conditions, calculate the drainage efficiency, and thus evaluate the anti-adhesion ability of the venous drainage tube.

[0036] Step 8: End of experiment, turn off the machine.

[0037] This circulatory testing system features functions such as pump speed adjustment and hemodynamic parameter monitoring. It can simulate blood flow environments under different clinical conditions, set up channel obstruction models of varying degrees, and simulate the effects of thrombosis. Using this system, the influence of venous drainage tube drainage methods on drainage efficiency and anti-adhesion function can be systematically studied, and the impact of obstruction on flow patterns can be assessed. Based on this, the structural parameters of the venous drainage tube can be optimized, and the insertion position can be appropriately adjusted to simulate the impact of different insertion positions on blood flow patterns, thereby optimizing the design of the venous drainage tube and drainage methods to improve clinical application.

Claims

1. A dual-loop circulation system for ex vivo drainage testing of extracorporeal membrane oxygenation (ECMO) venous drainage tubes, characterized in that, Includes a blood circulation simulation module and a venous drainage circulation module; The blood circulation simulation module includes: a blood circulation loop. and blood flow control loading and signal detection unit; the blood circulation circuit The system includes: a first programmable flow pump (A-1), a Y-type three-way valve (A-2), an inferior vena cava simulation tube (A-3), a reservoir bottle (A-4), and a lifting platform (A-5). The first programmable flow pump (A-1) drives the solution in the reservoir bottle (A-4) fixed on the lifting platform (A-5) via flow waveform programming control. The solution is pumped through a conduit into the first inlet of the Y-type three-way valve (A-2), flows through the inferior vena cava simulation tube (A-3), and finally flows back to the reservoir bottle (A-4). The inferior vena cava simulation tube (A-3) is made of different materials and has different rigidities depending on the size, shape, and testing conditions of the human inferior vena cava. The reservoir bottle (A-4) is fixed on the lifting platform (A-5) and is higher than the common horizontal plane of the first programmable flow pump (A-1), the Y-type three-way valve (A-2), and the inferior vena cava simulation tube (A-3). The lifting platform (A-5) can adjust the vertical height of the reservoir bottle (A-4). Using Pascal's Law By adjusting the height Provide basic pressure value This is used to simulate the baseline pressure of the inferior vena cava, where... Indicates the density of the solution. Represents gravitational acceleration; The blood flow control loading and signal detection unit includes: a main control host computer (C-1), a first microcontroller and drive module (C-2), a DC power supply (C-3), and a first flow sensor (C-4). The first microcontroller and drive module (C-2) consists of a microcontroller and a motor drive module. The main control host computer (C-1) inputs instructions to the microcontroller in the first microcontroller and drive module (C-2) via a communication wire. The first flow sensor (C-4) is located at the outlet pipe of the first programmable flow pump (A-1). It converts the flow information into flow velocity information using the formula: flow velocity V = flow rate Q / pipe diameter cross-sectional area S, and then transmits it back to the main control host computer (C-1) via the communication wire to the microcontroller in the first microcontroller and drive module (C-2). The DC power supply (C-3) provides a stable power electrical signal to the motor drive module in the first microcontroller and drive module (C-2). After being processed by the motor drive module, the signal is applied to the first programmable flow pump (A-1) to generate stable motor torque and speed. The aforementioned venous drainage circulation module includes: a venous drainage circulation circuit. Drainage control and signal detection unit; the aforementioned venous drainage circulation circuit Includes: a second programmable flow pump (B-1) and a venous drainage tube (B-2); the second programmable flow pump (B-1) controls the flow waveform to draw the solution from the venous drainage tube (B-2) located in the inferior vena cava simulation tube (A-3) and extending to the second inlet of the Y-type three-way tube (A-2), and then draws the solution from the inferior vena cava simulation tube (A-3) through a catheter to a storage bottle (A-4) fixed on the lifting platform (A-5); The drainage control and signal detection unit includes: a second microcontroller and drive module (D-1), a second flow sensor (D-2), a wireless pressure sensor (D-3), and a wireless flow sensor (D-4). The second microcontroller and drive module (D-1) consists of a microcontroller and a motor drive module. The host computer (C-1) sends commands to the microcontroller in the second microcontroller and drive module (D-1) via a communication cable. The second flow sensor (D-2) is located at the outlet of the venous drainage tube (B-2). It converts the flow information into velocity information using the formula: Flow velocity V = Flow rate Q / Pipe diameter / Cross-sectional area S, and then transmits the velocity information to the second microcontroller and drive module (D-4) via the communication cable. 1) The microcontroller in the first part sends the data back to the host computer (C-1); the wireless pressure sensor (D-3) and the wireless flow sensor (D-4) are set at the part of the inferior vena cava simulation tube (A-3) of the venous drainage tube (B-2) to transmit the drainage flow rate and pressure information at the venous drainage tube (B-2) in real time back to the host computer (C-1). The changes in drainage flow rate and pressure information reflect the drainage efficiency and the adhesion to the wall. The DC power supply (C-3) provides a stable power electrical signal to the second microcontroller and the motor drive module in the drive module (D-1). After being processed by the motor drive module, the signal is applied to the second programmable flow pump (B-1) to generate a stable motor torque and speed. The selection of the inferior vena cava simulation tube (A-3) is as follows: an elastic flexible tube with the same mechanical properties as the human inferior vena cava is used to test the drainage efficiency and wall adhesion during the drainage process; a transparent rigid tube is used to eliminate the influence of wall adhesion during the drainage process and to test the drainage efficiency separately.

2. The dual-loop circulation system for ex vivo drainage testing of extracorporeal membrane oxygenation venous drainage tubes according to claim 1, characterized in that, The blood flow control loading and signal detection unit adopts a proportional-integral-derivative control method. The first flow sensor (C-4) transmits the flow velocity information back to the microcontroller in the first microcontroller and the driver module (C-2). The microcontroller continuously fits the measured flow velocity information with the simulated waveform of the inferior vena cava input to the human body, and outputs a continuously corrected pulse width modulation signal. The signal is then loaded onto the first programmable flow pump (A-1) through the driver module to accurately output the set flow velocity waveform.

3. The dual-loop circulation system for ex vivo drainage testing of extracorporeal membrane oxygenation venous drainage tubes according to claim 1, characterized in that, The aforementioned venous drainage tube (B-2) uses venous drainage tubes with different numbers of side holes, levels of side holes, and spatial distribution structural parameters of side holes, in order to test the drainage efficiency and wall adhesion of different venous drainage tubes.

4. The dual-loop circulation system for ex vivo drainage testing of extracorporeal membrane oxygenation venous drainage tubes according to claim 1, characterized in that, The drainage control and signal detection unit adopts a proportional-integral-derivative control method. The second flow sensor (D-2) transmits the flow velocity information back to the microcontroller in the second microcontroller and the driver module (D-1). The microcontroller continuously fits the measured flow velocity information with the input venous drainage waveform and outputs a continuously corrected pulse width modulation signal. This signal is then loaded onto the second programmable flow pump (B-1) by the driver module to accurately output the set flow velocity waveform.

5. A dual-loop circulation system for ex vivo drainage testing of extracorporeal membrane oxygenation (ECMO) venous drainage tubes according to claim 1, characterized in that, The effects of venous drainage tube structure and drainage method on drainage efficiency and venous apposition to the vein wall were investigated using a double-loop circulation system. The experimental steps are as follows: Step 1: Inferior vena cava simulation tube (A-3) A rigid tube was used to conduct a venous drainage experiment under different pressure conditions to test the effect of venous drainage tube structure and drainage method on drainage efficiency; Step 2: Using a venous simulation tube with in vivo venous elasticity characteristics, conduct venous drainage experiments under different pressure conditions to test the effects of venous drainage tube structure and drainage method on drainage efficiency and anti-adhesion function.

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