Liver blood flow in-vitro simulation device based on porous medium resistance module

Abstract

The invention discloses a liver blood flow in-vitro simulation device based on a porous medium resistance module. The liver blood flow in-vitro simulation device comprises a portal vein simulation block, a liver simulation block and a vein backflow simulation block. The liver simulation block comprises a porous medium plate water tank, and three porous medium rotating partition plate assemblies with adjustable horizontal pose angles are arranged in cavities in the two sides of the porous medium plate water tank; the portal vein simulation block comprises a water tank, a water pump and a portal vein model of a Y-shaped pipe body structure. The portal vein model is detachably connected between the water pump and the porous medium plate water tank. The venous backflow simulation block comprises two backflow branches which are communicated with the interior of the water tank through a three-way pipe. By adjusting the included angle between the porous medium plate and the water flow direction and dynamically controlling the fluid resistance, the hemodynamic characteristics of cirrhosis of different degrees in the physiological state can be simulated, the simulation effect is optimized by monitoring the flow and pressure changes in real time, and experimental support is provided for liver physiology and pathology research.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomedical engineering experimental equipment, and particularly relates to a modular experimental device for simulating the pathophysiological process of the liver based on a porous medium module, which is particularly suitable for the hemodynamic study of portal hypertension and the in vitro test of interventional devices. Background Art

[0002] In biomedical research, simulating the physiological processes of human organs is of great significance for understanding disease mechanisms, medical staff teaching and training, and the development of treatment methods. The liver is an important metabolic organ in the human body, and its blood flow characteristics are of great significance for physiological and pathological research. Liver cirrhosis is a common liver disease that causes changes in the internal structure of the liver, increasing the resistance of liver blood flow and thus affecting blood flow characteristics. Therefore, studying the physiological and pathological processes of liver blood flow is of great significance for understanding the pathogenesis of liver cirrhosis and developing treatment methods.

[0003] Currently, the research on liver blood flow mainly relies on animal experiments or numerical simulations. Although animal experiments can provide relatively real physiological data, they have problems such as high cost, ethical restrictions, and species differences. Although numerical simulations can avoid these problems, the accuracy of their results highly depends on model assumptions and boundary conditions, and it is difficult to fully reflect the real physiological process.

[0004] To overcome the above problems, researchers have developed some experimental devices for simulating liver blood flow. These devices usually simulate the blood flow characteristics of the liver through a fixed resistance design, and it is difficult to dynamically adjust the resistance to simulate different degrees of pathological states, such as different stages of liver cirrhosis. In addition, the existing devices also have deficiencies in the precise control and real-time monitoring of hydrodynamic characteristics, and it is difficult to meet the high-precision experimental requirements.

[0005] Therefore, there is an urgent need to develop a device that can dynamically adjust the resistance and real-time monitor the hydrodynamic characteristics to accurately simulate the blood flow characteristics under different degrees of liver cirrhosis, that is, the physiological and pathological processes of liver blood flow, and provide a reliable experimental means for the research and treatment of liver cirrhosis. Summary of the Invention

[0006] In view of the technical defects of the existing liver blood flow simulation devices, such as insufficient dynamic regulation ability and poor anatomical adaptability, the present invention provides an in vitro liver blood flow simulation device based on a porous medium resistance module, which is used to simulate the liver blood flow state and has functions such as dynamically adjusting resistance, real-time monitoring, and accurately simulating the physiological conditions of different degrees of liver cirrhosis. The portal vein model fabricated by 3D printing accurately simulates the individualized portal vein anatomical structure and the hemodynamic characteristics of different degrees of liver cirrhosis; by rotating and positioning the horizontal pose angle of the porous medium plate, the resistance in the liver area is dynamically adjusted to simulate the pathological evolution from the compensated stage to the decompensated stage of liver cirrhosis; at the same time, the flow rate and pressure parameters at the portal vein inlet and the hepatic vein outlet are monitored in real time to provide high-precision data support for experimental research.

[0007] To solve the above technical problems, one technical solution adopted by the present invention is:

[0008] An in vitro liver blood flow simulation device based on a porous medium resistance module, comprising a portal vein simulation block, a liver simulation block, and a venous return simulation block;

[0009] The liver simulation block includes a porous medium plate water tank and a porous medium partition plate disposed in the porous medium plate water tank. The porous medium partition plate divides the interior of the porous medium plate water tank into two independent chambers, and each chamber is provided with three porous medium rotating partition plate assemblies with adjustable horizontal pose angles;

[0010] The portal vein simulation block includes a water tank, a water pump, and a portal vein model in a "Y" - shaped tube structure. The input end of the water pump is communicated with the interior of the water tank, the main input end of the portal vein model is detachably connected to the output end of the water pump, and the two branch output ends of the portal vein model are respectively communicated with the interiors of the input ends of the two independent chambers of the porous medium plate water tank;

[0011] The venous return simulation block includes two return branches respectively communicated with the output ends of the two independent chambers of the porous medium plate water tank, a tee pipe connected to the output ends of the two return branches, and the output end of the tee pipe is communicated with the interior of the water tank.

[0012] Further, the porous medium rotating partition plate assembly includes a cylindrical grille fixedly disposed in the chamber of the porous medium plate water tank, a porous medium plate disposed in the cylindrical grille, and a plastic diversion plate. A plurality of water - permeable holes are uniformly arranged on the plastic diversion plate. The outer wall of the cylindrical grille is hermetically connected to the porous medium partition plate and the side wall of the porous medium plate water tank respectively. The porous medium plate and the plastic diversion plate are orthogonally formed into a cross - shaped structure, and a positioning rotating shaft is fixedly disposed at the center of the top surface of the cross - shaped structure, and the positioning rotating shaft is fixedly clamped by a rotation fixing mechanism.

[0013] Further, the rotation fixing mechanism includes a vertical fixing rod fixedly connected to the top end of the side wall of the porous medium plate water tank, a first fixing block inserted into the top end of the vertical fixing rod, a horizontal fixing rod arranged on the side surface of the first fixing block, and a second fixing block fixedly arranged on the cantilever end of the horizontal fixing rod. The top of the positioning rotating shaft is inserted into the second fixing block through a spline.

[0014] Further, angle scale lines are arranged on the top surface of the second fixing block, and an indicating line is arranged on the outer wall of the positioning rotating shaft.

[0015] Further, a support rotating shaft is fixedly arranged at the center of the bottom surface of the cross-shaped structure, and a positioning groove matching the support rotating shaft is arranged on the bottom wall of the porous medium plate water tank.

[0016] Further, the outer edges of the porous medium plate and the plastic diversion plate are in sliding contact with the inner wall of the cylindrical grille.

[0017] Further, both the porous medium plate and the porous medium partition are made of a porous medium material with a pore diameter of 0.01 mm to 1 mm.

[0018] Further, a reflux bypass is also arranged at the input end and the output end of each chamber of the porous medium plate water tank. Water stop valves are arranged at the input end of the chamber and the input end of the reflux bypass, and the opening and closing states of the two water stop valves are opposite.

[0019] Further, a main fluid flow parameter measuring mechanism is arranged at the output end of the water pump, and a branch fluid flow parameter measuring mechanism is arranged at one of the branch output ends of the portal vein model.

[0020] Further, reflux branch fluid flow parameter measuring mechanisms are arranged at the output ends of the two reflux branches of the venous return simulation block.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] 1. Individualized adaptation ability: Adopting a modular subsystem architecture, the portal vein model is made by 3D printing, and the portal vein model can be quickly replaced in the fluid passage through a quick-connect joint, which can accurately simulate the vascular structures of different patients (such as the bifurcation angle of the portal vein and the difference in pipe diameter), providing an experimental platform for clinical preoperative planning.

[0023] 2. Dynamic pathological simulation accuracy: The dual adjustment mechanism of the pore size and angle of the porous medium plate can reproduce the multi-level adjustment of the blood flow resistance change from F1 (mild fibrosis) to F4 (cirrhosis) of liver cirrhosis. Through the design of the rotatable porous medium plate, it can simulate the blood flow characteristics under different degrees of liver cirrhosis, and dynamically adjust the water flow resistance, accurately simulate the hemodynamic characteristics of different degrees of liver cirrhosis, and provide an intuitive and controllable experimental platform for biomedical research. The angle scale and spline positioning mechanism work together to achieve a repeat positioning accuracy of ±0.5° for the rotation angle.

[0024] 3. Monitoring and feedback: A distributed monitoring network is adopted, and non-invasive measurement is carried out by an external clip-on ultrasonic sensor to avoid the interference of the traditional invasive probe on the flow field. The data sampling frequency reaches 100Hz, meeting the requirements of transient blood flow analysis; through the flow parameter measurement mechanism of the flow sensor and pressure sensor, the changes in flow and pressure are monitored in real time, providing high-precision data support for the experiment; the device has a simple structure and is easy to operate, suitable for a variety of experimental scenarios of liver physiology and pathology research. It can not only provide strong support for the research of liver diseases such as liver cirrhosis, but also be widely applied in the fields of biofluid mechanics and medical teaching.

[0025] 4. Low cost and easy maintenance: The structural design such as the acrylic water tank and standardized quick-release interface can significantly reduce the equipment purchase and maintenance costs, and is suitable for popularization and application in scientific research institutions and medical institutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is the overall structural schematic diagram of the in vitro liver blood flow simulation device of the present invention;

[0027] Figure 2 is the structural schematic diagram of the portal vein simulation block of the present invention;

[0028] Figure 3 is the structural schematic diagram of the liver simulation block of the present invention;

[0029] Figure 4 is the structural schematic diagram of the venous return simulation block of the present invention;

[0030] Figure 5 is the sectional structural schematic diagram of the portal vein model of the present invention;

[0031] Figure 6 is the structural schematic diagram of the porous medium plate water tank and its internal components of the present invention;

[0032] Figure 7 is the structural schematic diagram of the composite porous medium rotating partition assembly of the present invention;

[0033] Figure 8Schematic cross-sectional structure diagram of the composite porous medium rotating partition of the present invention;

[0034] Figure 9 Schematic structure diagram of the rotating fixing mechanism of the porous medium plate water tank of the present invention;

[0035] Figure 10 Schematic top view structure and angle-resistance relationship diagram of the porous medium water tank of the present invention;

[0036] Figure 11 Schematic diagram of the hydraulic system of the present invention. Detailed implementation manners

[0037] The following elaborates on the preferred embodiments of the present invention in conjunction with the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making the protection scope of the present invention more clearly defined.

[0038] It should be noted that when a component is referred to as "installed on" another component, it can be directly on the other component or there may also be an intermediate component. When a component is considered to be "disposed on" another component, it can be directly disposed on the other component or there may be an intermediate component at the same time. When a component is considered to be "fixed to" another component, it can be directly fixed to the other component or there may be an intermediate component at the same time.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The term "or / and" used herein includes any and all combinations of one or more of the related listed items.

[0040] Embodiment 1:

[0041] As Figure 1 shown, a liver blood fluid in vitro simulation device based on a porous medium resistance module includes a portal vein simulation block 1, a liver simulation block 2, and a venous return simulation block 3.

[0042] The liver simulation block 2 includes a porous medium plate water tank 26 and a porous medium partition plate 266 disposed within the porous medium plate water tank 26. Among them, the porous medium plate water tank 26 is a cubic trough structure with an open top, which is bonded by a front side plate 261, a left side plate 262, a rear side plate 263, a right side plate 264, and a bottom plate 265. Each side plate is made of transparent acrylic plate, which can not only reduce the overall mass and manufacturing cost of the porous medium plate water tank 26, but also make the interior of the porous medium plate water tank 26 in a perspective state, facilitating the observation of the fluid state within the porous medium plate water tank 26 from all directions during the simulation demonstration process. The porous medium partition plate 266 is made of a porous medium material with a pore diameter of 0.01 mm to 1 mm (porous ceramic material in this embodiment), and is vertically disposed at the center inside the porous medium plate water tank 26. Moreover, it is hermetically adhesively connected between the front end and the front side plate 261, between the rear end and the rear side plate 263, and between the bottom end and the bottom plate 265 respectively, thereby dividing the interior of the porous medium plate water tank into two independent chambers, hereinafter referred to as the left chamber and the right chamber. Openings communicating with the two chambers are respectively provided on the front side plate 261 and the rear side plate 263, and water pipe connectors are fixedly and hermetically installed in the openings for connecting the supply pipeline and the discharge pipeline of the fluid within the porous medium plate water tank 26.

[0043] As Figure 6 shown, three porous medium rotary partition plate assemblies with adjustable horizontal pose angles are provided in both the left chamber and the right chamber. The three porous medium rotary partition plate assemblies in a single chamber are evenly distributed at equal intervals in the front-rear direction, and the porous medium rotary partition plate assemblies in the two chambers are symmetrically distributed on the left and right sides of the porous medium partition plate 266.

[0044] Taking the left chamber as an example, as Figure 7 shown, the porous medium rotary partition plate assembly includes a cylindrical grille 2673 fixedly disposed in the left chamber, a porous medium plate 2672 disposed within the cylindrical grille 2673, and a plastic diversion plate 2671. Among them, the cylindrical grille 2673 is a stainless steel cylindrical frame, and the gap between the outer wall of the cylindrical grille 2673 and the porous medium partition plate 266 and the side wall of the porous medium plate water tank 26 (here it is the left side plate 262) ≤ 0.05 mm, preferably hermetically connected, so that all the fluid in the porous medium plate water tank 26 flows through the inside of the cylindrical grille 2673 and will not leak through the left and right sides of the cylindrical grille 2673. The porous medium plate 2672 is also made of a porous ceramic material with a pore diameter of 0.01 mm to 1 mm, and a number of water permeable holes are evenly provided on the plastic diversion plate 2671, which can conduct water and divert. The vertical height of the cylindrical grille 2673 is the same as the height of the porous medium plate 2672.

[0045] The porous medium plate 2672 and the plastic deflector plate 2671 are orthogonal to form a cross-shaped structure. The two are fixedly connected to form a composite porous medium rotating partition assembly. The outer edges of the porous medium plate 2672 and the plastic deflector plate 2671 are in sliding contact with the inner wall of the cylindrical grille 2673. In this way, all the water flowing through the cylindrical grille 2673 can flow backward through the penetration of the porous medium plate 2672 and the water permeability of the plastic deflector plate 2671. At the same time, the cross-shaped structure can rotate smoothly in the cylindrical grille 2673 to adjust the horizontal pose angle. According to different simulation parameter requirements, the required penetration and water permeability can be adjusted by replacing the pore size of the porous medium and / or the pore size of the water-permeable holes, and cooperating with the adjustment of the horizontal pose angle of the cross-shaped structure to simulate different degrees of portal hypertension conditions.

[0046] A positioning rotating shaft 2674 is fixedly arranged at the center of the top surface of the composite porous medium rotating partition assembly. The positioning rotating shaft 2674 is fixedly clamped by a rotating fixing mechanism 268. Still taking the left chamber as an example, as Figure 9 shown, the rotating fixing mechanism 268 includes a vertical fixing rod 2684 fixedly connected to the top end of the side wall of the porous medium plate water tank 26 (here it is the left side plate 262), a first fixing block 2681 inserted into the top end of the vertical fixing rod 2684, a horizontal fixing rod 2682 arranged on the side surface of the first fixing block 2681, and a second fixing block 2683 fixedly arranged at the cantilever end of the horizontal fixing rod 2682. Specifically, a threaded hole is opened on the bottom surface of the left side plate 262. The bottom end of the vertical fixing rod 2684 is a threaded section and is in threaded fit with the threaded hole, so that the vertical fixing rod 2684 is vertically fixedly arranged. A jack is arranged on the bottom surface of the first fixing block 2681, which is in plug-in fit with the top end of the vertical fixing rod 2684, so that it is detachably fixedly arranged on the vertical fixing rod 2684, facilitating the adjustment operation of the horizontal pose angle of the positioning rotating shaft 2674. Through holes are opened on the opposite side surfaces of the first fixing block 2681 and the second fixing block 2683, and they are respectively in plug-in fit with both ends of the horizontal fixing rod 2682. The top of the positioning rotating shaft 2674 is inserted into the second fixing block 2683 through a spline. In this way, the first fixing block 2681 and the second fixing block 2683 can be lifted synchronously by the horizontal fixing rod 2682, so that the second fixing block 2683 is separated from the top of the positioning rotating shaft 2674. At this time, the positioning rotating shaft 2674 is in a freely rotatable state. Rotating the positioning rotating shaft 2674 can realize the adjustment of the horizontal pose angle of the composite porous medium rotating partition assembly; after adjustment, the first fixing block 2681 and the second fixing block 2683 can be pressed down synchronously by the horizontal fixing rod 2682. The second fixing block 2683 is sleeved on the outer side of the top of the positioning rotating shaft 2674 again through a spline, and the first positioning block 2681 is fixedly buckled on the top end of the vertical fixing rod 2684 again to realize the position locking of the composite porous medium rotating partition assembly.

[0047] Preferably, angle scale lines are provided on the top surface of the second fixing block 2683. In this embodiment, the central angle corresponding to adjacent scale lines is 5°, and the corresponding number of spline teeth is 360° / 5° = 72. An indicating line is provided on the outer wall of the positioning rotating shaft 2674. Through the cooperation of the indicating line and the angle scale lines, the horizontal pose angle of the cross-shaped structure can be easily and accurately adjusted. Further, to ensure that the composite porous medium rotating partition assembly and the cylindrical grid 2673 are always coaxially arranged, and to facilitate the rotation operation of the composite porous medium rotating partition assembly, a support rotating shaft 2675 coaxially arranged with the positioning rotating shaft 2674 is fixedly provided at the center of the bottom surface of the composite porous medium rotating partition assembly, and a positioning groove matching the bottom end of the support rotating shaft 2675 is provided on the top surface of the bottom plate 265 of the porous medium plate water tank 26. At the same time, after the second fixing block 2683 is re-fitted and sleeved with the positioning rotating shaft 2674, to ensure that the composite porous medium rotating partition assembly does not have axial looseness during the simulation process, two fixing rings 2685 are sleeved on the positioning rotating shaft 2674 and are respectively located at the upper and lower surface positions of the second fixing block 2683.

[0048] As Figure 10 shown, the top view structure of the porous medium plate water tank 26 clearly shows the dynamic correlation mechanism between the rotation angle θ of the composite porous medium rotating partition assembly and the fluid resistance. The rotation angle θ is the horizontal angle between the surface of the porous medium plate 2672 and the water flow direction, 0°≤θ≤90°, and is accurately calibrated by the scale lines on the upper surface of the second fixing block 2683; the rotation angle range of each porous medium plate 2672 is from 0° to 90°. When the rotation angle is 0°, that is, the porous medium plate 2672 is parallel to the inlet fluid direction of the porous medium plate water tank 26, the resistance to the fluid is the smallest at this time; when the rotation angle is 90°, that is, perpendicular to the inlet fluid direction of the porous medium plate water tank 26, the resistance to the fluid is the largest at this time.

[0049] As Figure 3As shown, the outer end of the water pipe joint at the input end of the left chamber of the porous medium plate water tank 26 is connected to a left main passage valve 252. The input end of the left main passage valve 252 is connected to a left three-way pipe 212. One port of the left three-way pipe 212 is connected to a left bypass valve 221. The outer end of the water pipe joint at the input end of the left chamber is connected to a left four-way pipe 241. One port of the left four-way pipe 241 is connected to the outlet end of the left bypass valve 221 through a first pipeline. Both ends of the first pipeline are supported by a first pipeline bracket 231 and a second pipeline bracket 232 respectively. The left three-way pipe 212, the left main passage valve 252, the left chamber and the left four-way pipe 241 form the left main passage of the left branch fluid, and the left three-way pipe 212, the left bypass valve 221 and the left four-way pipe 241 form the left return bypass of the left branch fluid. Similarly, the outer end of the water pipe joint at the input end of the right chamber is connected to a right main passage valve 251. The input end of the right main passage valve 251 is connected to a right three-way pipe 211. One port of the right three-way pipe 211 is connected to a right bypass valve 222. The outer end of the water pipe joint at the input end of the right chamber is connected to a right four-way pipe 242. One port of the right four-way pipe 242 is connected to the outlet end of the right bypass valve 222 through a second pipeline. Both ends of the second pipeline are supported by a third pipeline bracket 233 and a fourth pipeline bracket 234 respectively. The right three-way pipe 211, the right main passage valve 251, the right chamber and the right four-way pipe 242 form the right main passage of the right branch fluid, and the right three-way pipe 211, the right bypass valve 222 and the right four-way pipe 242 form the right return bypass of the right branch fluid. One port of the left four-way pipe 241 is connected to one port of the right four-way pipe 242.

[0050] By controlling the opening and closing of the left bypass valve 221 and the left main passage valve 252, the drainage flow rate in the left chamber can be restricted. Similarly, by controlling the opening and closing of the right bypass valve 222 and the right main passage valve 251, the drainage flow rate in the right chamber can be restricted, so as to simulate the situation of hepatic vein obstruction.

[0051] As Figure 2 shown, the portal vein simulation block 1 includes a water tank 11, a water pump 13 and a portal vein model 15 in a "Y"-shaped pipe structure. The water tank 11 is used to store the fluid for the simulation experiment. The fluid can be a colored mixed solution close to the density and viscosity of human blood, so as to facilitate observing the fluid flow situation and obtaining more accurate experimental results. The input end of the water pump 13 is communicated with the inside of the water tank 11. The output end of the water pump 13 is provided with a main fluid flow parameter measurement mechanism composed of a first external clamp type ultrasonic flowmeter 141 and a first pressure sensor 142. The main input end of the portal vein model 15 is detachably connected to the output end of the main fluid flow parameter measurement mechanism. Specifically, as Figure 5As shown in the figure, based on the CT, MRI and other imaging data of the healthy portal vein provided by the hospital, a model of the portal vein blood vessel is established through 3D modeling software, and a portal vein model made of fully transparent silicone material is fabricated using 3D printing technology. The portal vein model 15 includes a left bifurcation structure 151 and a right bifurcation structure 152 of the portal vein.

[0052] At the output end nozzle of the main trunk fluid flow parameter measuring mechanism, a first quick-release joint 161 (such as the quick-connect joint of a washing machine water inlet pipe, the same below) is provided, and the input end of the main trunk of the portal vein model 15 is plugged into the first quick-release joint 161. At the input end nozzle of the left three-way pipe 212, a branch fluid flow parameter measuring mechanism composed of a second external clamp-on ultrasonic flowmeter 144 and a second pressure sensor 143 is provided. At the input end nozzle of the branch fluid flow parameter measuring mechanism, a second quick-release joint 162 is provided, and the branch output end of the left bifurcation structure 151 of the portal vein is plugged into the second quick-release joint 162. At the input end nozzle of the right three-way pipe 211, a connecting water pipe is provided. At the nozzle of the connecting water pipe, a third quick-release joint 163 is provided, and the branch output end of the right bifurcation structure 152 of the portal vein is plugged into the third quick-release joint 163. The connecting water pipe is supported by a fifth pipeline bracket 17.

[0053] A water stop valve 12 is provided on the side wall of the water tank 11, and its input end is connected to the reflux output end of the venous reflux simulation block 3, so that the reflux fluid flows into the water tank 11 unidirectionally through the water stop valve 12.

[0054] As Figure 4 shown, the venous reflux simulation block 3 includes a left reflux branch internally communicating with the output end of the left chamber of the porous medium plate water tank 26 and a right reflux branch internally communicating with the output end of the right chamber. The output end nozzles of the two reflux branches are commonly connected to a reflux three-way pipe 32, and the output end nozzle of the reflux three-way pipe 32 is connected to the input end of the water stop valve 12 on the water tank 11 through a pipeline. Among them, a left reflux branch fluid flow parameter measuring mechanism composed of a third external clamp-on ultrasonic flowmeter 311 and a third pressure sensor 312 is provided on the left reflux branch, and a right reflux branch fluid flow parameter measuring mechanism composed of a fourth external clamp-on ultrasonic flowmeter 313 and a fourth pressure sensor 314 is provided on the right reflux branch.

[0055] Example 2:

[0056] Normal liver blood flow simulation:

[0057] As shown in the appendix Figure 11 shown, it is the hydraulic system schematic diagram of the in vitro liver blood flow simulation device based on the porous medium resistance module. This device adopts a three-stage modular hydraulic architecture, which fully presents the fluid dynamics simulation mechanism of the portal vein-liver-vein circuit. The fluid flow routes of each module are as follows:

[0058] Portal vein module: water tank 11 → water pump 13 → main flow parameter measuring mechanism → portal vein model 15 → branch fluid flow parameter measuring mechanism;

[0059] Liver module: left portal vein bifurcation structure 151 / right portal vein bifurcation structure 152 → porous medium water tank 26 → left four-way pipe 241 / right four-way pipe 242;

[0060] Vein module: return three-way pipe 32 → left / right return branch fluid flow parameter measuring mechanism → water tank 11.

[0061] The specific simulation steps are as follows:

[0062] In the portal vein simulation block 1, insert the main input end of the portal vein model 15 into the first quick-release joint 161, insert the branch output end of the left portal vein bifurcation structure 151 into the second quick-release joint 162, and insert the branch output end of the right portal vein bifurcation structure 152 into the third quick-release joint 163 to complete the setting of the portal vein model 15 in the flow path.

[0063] In the liver simulation block 2, close the left main passage valve 252 and the right main passage valve 251, and open the left bypass valve 221 and the right bypass valve 222. Position the composite porous medium rotating partition assembly composed of the porous medium plate 2672 and the plastic deflector 2671 at the corresponding assembly positions in the porous medium plate water tank 26 respectively. Assemble the cylindrical grille 2673, apply epoxy glue on the left and right sides of the cylindrical grille 2673, and apply a torque of 5 - 7 N·m to tighten the epoxy glue seam, and check whether the gap between the cylindrical grille 2673 and the side wall of the porous medium plate water tank 26 is precisely bonded. Adjust the porous medium plate 2672 in the porous medium water tank 26 to a rotation angle θ of 0°, so that the porous medium plate 2672 is parallel to the water flow direction. After the angle is adjusted, lock the position of the composite porous medium rotating partition assembly through the fixing ring 2685, and check whether the positioning rotating shaft 2674 and the second fixing block 2683 are relatively fastened.

[0064] Then, start the water pump 13 and circulate and supply the fluid at a flow rate of 0.5 L / min for 30 minutes. During this process, the fluid directly enters the left return branch and the right return branch of the venous return simulation block 3 through the left return bypass and the right return bypass on both sides of the porous medium water tank 26, and then converges and returns to the water tank 11 to remove the air bubbles in the fluid until no air bubbles are discharged from the water tank 11 in the portal vein simulation block 1. After the fluid enters the porous medium water tank 26 through the water inlet, it is forced to be blocked by the cylindrical grille 2673 outside the composite porous medium rotating partition assembly, changing the flow-around path and being diverted to the porous medium area to ensure that the fluid passes through the porous medium plate 2672 and the plastic deflector 2671.

[0065] Close the left bypass valve 221 and the right bypass valve 222, open the left main passage valve 252 and the right main passage valve 251, adjust the water pump 13 to the target flow rate Q. After the flow rate is stabilized, measure the dynamic experimental parameters related to the fluid flow in each passage respectively through the main fluid flow parameter measurement mechanism, the branch fluid flow parameter measurement mechanism, and the return branch fluid flow parameter measurement mechanism.

[0066] After maintaining steady-state operation for 10 minutes, record the flow rate and pressure data at the portal vein inlet and the hepatic vein outlet, generate a flow rate-resistance curve, and calculate the corresponding resistance coefficient ζ according to the preset calculation formula.

[0067] Gradually reduce the rotational speed of the water pump 13 until it stops, close all valves, and disassemble the portal vein model 15, clean the pipeline to complete the process of this simulation experiment.

[0068] Example 3:

[0069] Pathological simulation of portal hypertension:

[0070] In the portal vein simulation block 1, install the portal vein model 15 and check the sealing performance at the connection with each quick-disconnect joint. Check the positioning distance between each pipeline support and each fluid flow parameter measurement mechanism to avoid fluid disturbance.

[0071] As Figure 10 shown: In the liver simulation block 2, adjust the horizontal pose angles of the porous medium plates 2672 in the left and right chambers of the porous medium water tank 26, that is, adjust the corresponding rotation angle θ, and simulate the physiological condition of inconsistent resistances in the left and right lobes of the liver by setting the resistance difference between the left and right chambers of the porous medium water tank 26. After the angle is adjusted, lock the position through the fixing ring 2685 and check to ensure that the position is reliably locked.

[0072] Set different specifications of porous medium plates and rotation angles θ according to the target liver cirrhosis grading in the following table.

[0073] Liver cirrhosis grading Rotation angle θ Porosity Φ Target pressure range F1 (mild) 0-30° 40％-45％ 10 mmHg - 15 mmHg F2 (moderate) 30°-60° 55％-60％ 16 mmHg - 25 mmHg F3 - F4 (severe) 90°-90° 70％-75％ 26 mmHg - 35 mmHg

[0074] When θ = 0°, the porous medium plate 2672 is parallel to the water flow direction, the streamline is approximately a straight line, and the flow velocity remains 92% of the inlet; when θ = 90°, the porous medium plate 2672 is completely perpendicular to the water flow direction, the streamline is a high-density zigzag path, and the flow velocity drops to 18% of the inlet.

[0075] The rotation angle of the porous medium plate 2672 is preset to θ = 30°, and its position is locked by the fixing ring 2685. The left main passage valve 252 and the right main passage valve 251 are closed, and the left bypass valve 221 and the right bypass valve 222 are opened. The water pump 13 is started and circulated at a flow rate of 0.8 L / min for 5 minutes. In the liver simulation block 2, it directly enters the left return branch and the right return branch of the venous return simulation block 3 through the left return bypass and the right return bypass on both sides of the porous medium water tank 26, and then converges and returns to the water tank 11 to remove the air bubbles in the fluid until no air bubbles are discharged from the water tank 11 in the portal vein simulation block 1. After the fluid enters the porous medium water tank 26 through the water inlet, it is forced to block by the cylindrical grille 2673 on the outer side of the composite porous medium rotating partition assembly, changing the flow-around path and being diverted to the porous medium area to ensure that the fluid passes through the porous medium plate 2672 and the plastic deflector 2671.

[0076] Manually adjust the rotation angle θ of the porous medium plate 2672 in the left and right chambers of the porous medium water tank 26 every 15 minutes, with a single angle difference of 5°. Synchronously record the corresponding pressure data and compare the error rate between the measured pressure and the theoretical value.

[0077] The high-precision pathological simulation is achieved through the following design in this embodiment:

[0078] (1) The design of the cross-shaped porous medium rotating partition and the peripheral grille expands the effective resistance adjustment range;

[0079] (2) Establish the quantitative relationship between liver cirrhosis grading - angle - pressure, and simulate the non-uniform situation of the liver by adjusting the resistance on both sides of the porous medium water tank.

[0080] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0081] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be included in the patent protection scope of the present invention by the same token.

Claims

1. An in vitro liver blood flow simulation device based on a porous medium resistance module, characterized in that: It includes portal vein simulation block, liver simulation block and venous return simulation block; The liver simulation block includes a porous medium plate water tank and a porous medium partition disposed in the porous medium plate water tank, wherein the porous medium partition divides the interior of the porous medium plate water tank into two independent chambers, and each chamber is provided with three porous medium rotating partition assemblies with adjustable horizontal posture angles; The portal vein simulation block includes a water tank, a water pump and a portal vein model of a "Y"-shaped tube structure, the input end of the water pump is connected to the inside of the water tank, the main input end of the portal vein model is detachably connected to the output end of the water pump, and the two branch output ends of the portal vein model are respectively connected to the input ends of two independent chambers of the porous medium plate water tank; The venous return simulation block includes two return branches respectively connected to the output ends of two independent chambers of the porous medium plate water tank, and a three-way pipe connected to the output ends of the two return branches, and the output end of the three-way pipe is connected to the inside of the water tank.

2. The liver blood flow simulation device in vitro based on the porous medium resistance module according to claim 1, characterized in that: The porous medium rotating baffle assembly includes a cylindrical grille fixedly arranged in the chamber of a porous medium plate water tank, a porous medium plate and a plastic guide plate arranged in the cylindrical grid, a plurality of water-permeable holes are evenly arranged on the plastic guide plate, the outer wall of the cylindrical grille is sealed and connected to the porous medium baffle and the side wall of the porous medium plate water tank respectively, the porous medium plate and the plastic guide plate are orthogonally connected to form a cross-shaped structure, a positioning shaft is fixedly arranged at the center of the top surface of the cross-shaped structure, and the positioning shaft is fixedly clamped by a rotating fixing mechanism.

3. The liver blood flow simulation device in vitro based on the porous medium resistance module according to claim 2 is characterized in that: The rotating fixing mechanism includes a vertical fixing rod fixedly connected to the top of the side wall of the porous medium plate water tank, a first fixing block plugged into the top of the vertical fixing rod, a horizontal fixing rod arranged on the side of the first fixing block, and a second fixing block fixedly arranged on the cantilever end of the horizontal fixing rod. The top of the positioning shaft is plugged into the second fixing block through a spline.

4. The liver blood flow simulation device in vitro based on the porous medium resistance module according to claim 3 is characterized in that: Angle scale lines are arranged on the top surface of the second fixing block, and indicator lines are arranged on the outer wall of the positioning shaft.

5. The liver blood flow simulation device in vitro based on the porous medium resistance module according to any one of claims 2 to 4, characterized in that: A supporting shaft is fixedly arranged at the center of the bottom surface of the cross-shaped structure, and a positioning groove matching the supporting shaft is arranged on the bottom wall of the porous medium plate water tank.

6. The liver blood flow simulation device in vitro based on the porous medium resistance module according to any one of claims 2 to 4, characterized in that: The outer edges of the porous medium plate and the plastic guide plate are in sliding contact with the inner wall of the cylindrical grille.

7. The liver blood flow simulation device in vitro based on the porous medium resistance module according to claim 6, characterized in that: The porous medium plate and the porous medium partition are both made of porous medium material with a pore size of 0.01 mm to 1 mm.

8. The liver blood flow simulation device in vitro based on the porous medium resistance module according to claim 1 or 2, characterized in that: The input and output ends of each chamber of the porous medium plate water tank are also provided with a reflux bypass, and the input end of the chamber and the input end of the reflux bypass are both provided with a water stop valve, and the opening and closing states of the water stop valves at the two locations are opposite.

9. The liver blood flow simulation device in vitro based on the porous medium resistance module according to claim 1 or 2, characterized in that: The output end of the water pump is provided with a main fluid flow parameter measuring mechanism, and one of the branch output ends of the portal vein model is provided with a branch fluid flow parameter measuring mechanism.

10. The liver blood flow simulation device in vitro based on the porous medium resistance module according to claim 9, characterized in that: The output ends of the two return branches of the venous return simulation block are both provided with return branch fluid flow parameter measurement mechanisms.

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