Arterial cannula for VA-ECMO

Abstract

The utility model belongs to the technical field of medical instruments, and provides an arterial cannula for VA-ECMO, which comprises a cannula body provided with a liquid guide cavity, one end of the cannula body is provided with a liquid injection port communicated with the liquid guide cavity, and the other end of the cannula body is a closed end; the tube body comprises a main body part and an arch-shaped part which are connected, the liquid injection port is formed in the end part of the main body part, and the closed end is arranged at the end part of the arch-shaped part; the arch-shaped part is in a bent arch shape matched with the aortic arch and is provided with a liquid outlet hole communicated with the liquid guide cavity. According to the artery cannula for VA-ECMO, one end of the cannula body is arranged to be the closed end, and the blood flow direction is changed through the liquid outlet hole, so that reverse blood flow of VA-ECMO through the femoral artery cannula is reduced, the left ventricular afterload is reduced more easily and more easily, complications caused by afterload increase are reduced, and the survival rate of VA-ECMO treatment patients is increased.

Description

Technical Field

[0001] This utility model belongs to the field of medical device technology, and specifically relates to an arterial cannula for VA-ECMO. Background Technology

[0002] Venous-arterial extracorporeal membrane oxygenation (VA-ECMO) is one of the most commonly used mechanical circulatory support modes in cardiogenic shock. However, complications such as bleeding, thrombosis, increased left ventricular afterload, and differential hypoxia can occur during VA-ECMO, thus affecting the treatment outcome. Among these, increased left ventricular afterload is one of the most significant side effects. Although VA-ECMO can drain blood from the right atrium and reduce cardiac preload, the non-physiological reverse blood flow provided by the arterial return catheter significantly increases aortic pressure and cardiac afterload, leading to increased cardiac work and myocardial oxygen consumption. Furthermore, increased left ventricular afterload may increase aortic valve orifice size, left ventricular pressure and congestion, left atrial pressure, and even pulmonary edema. During VA-ECMO, up to 70% of patients experience increased left ventricular afterload, and the probability of significant left ventricular dilation and pulmonary edema requiring unloading of the left ventricle is as high as 20%.

[0003] In clinical practice, afterload is generally considered as the resistance to the heart's pumping action, and arterial blood pressure is the main factor determining afterload. Increased aortic systolic pressure is a significant cause of increased cardiac afterload and increased cardiac workload, and the countercurrent blood flow between the heart and VA-ECMO is the main reason for elevated aortic pressure. Previous studies have shown that left ventricular unloading during VA-ECMO is associated with lower mortality.

[0004] Currently, clinical left ventricular unloading measures include balloon atrial septostomy (BAS), percutaneous left ventricular assist therapy (pLVAD), and surgery. However, these commonly used clinical unloading methods are all additional treatments on the basis of VA-ECMO, which not only increases the corresponding operation steps and complexity, but also increases the incidence of complications such as hemolysis and thrombosis, greatly increasing the treatment burden on patients and their families.

[0005] Therefore, there is a need to design an arterial cannula for VA-ECMO that can effectively solve the above problems and defects. Summary of the Invention

[0006] To address the above-mentioned technical problems, this invention proposes an arterial cannula for VA-ECMO. By setting one end of the cannula as a closed end and changing the blood flow direction through the outlet, the reverse blood flow in VA-ECMO via the femoral artery cannula is reduced, making it easier to reduce left ventricular afterload, reducing complications caused by increased afterload, and improving the survival rate of patients treated with VA-ECMO.

[0007] The technical solution of this utility model is:

[0008] This utility model proposes an arterial cannula for VA-ECMO, including a tube body with a fluid guiding cavity, one end of the tube body having an injection port connected to the fluid guiding cavity, and the other end being a closed end;

[0009] The tube body includes a main body and an arc-shaped part connected to each other, the injection port is located at the end of the main body, and the closed end is located at the end of the arc-shaped part;

[0010] The bow-shaped portion is a curved bow shape adapted to the aortic arch, and it is provided with an outlet hole that communicates with the fluid guiding cavity.

[0011] Preferably, the liquid outlet is perpendicular to the plane of the arc-shaped portion, and the liquid outlet is provided on at least one side of the arc-shaped portion.

[0012] Preferably, the diameter of the liquid outlet hole is between 1 and 3 mm.

[0013] Preferably, there are several outlet holes, which are evenly spaced along the pipeline of the arc-shaped portion.

[0014] Preferably, the distance between adjacent liquid outlet holes is between 1 and 3 cm.

[0015] Preferably, the tube body is provided with an inner guide wire and an outer guide wire that are movably embedded in its tube wall. One end of the inner guide wire and the outer guide wire are fixedly connected to the closed end of the tube body, and the other end extends movably out of the tube body.

[0016] Preferably, the end of the inner guide wire near the closed end of the tube body is in the shape of an arc that matches the arc-shaped part, and it is arranged on the inner arc side near the arc-shaped part;

[0017] The end of the external guide wire near the closed end of the tube body is in the shape of an arc that matches the arc-shaped part, and it is arranged on the outer arc side near the arc-shaped part.

[0018] Preferably, the tube body further includes a traction part connected to the main body, and the traction part is provided with a traction knob movably connected thereto;

[0019] The movable ends of both the inner and outer traction guide wires are fixedly connected to the traction knob.

[0020] Preferably, the traction knob is provided with symmetrically distributed inner and outer rudders, the inner rudder is fixedly connected to the movable end of the inner traction guide wire, and the outer rudder is fixedly connected to the movable end of the outer traction guide wire.

[0021] Preferably, the main body and the bow-shaped part are connected in an integral structure.

[0022] This utility model has the following advantages and effects compared with the prior art:

[0023] The tube is designed with one end closed, and the blood flow direction is altered by a side outlet. This ensures that the blood flow direction at the outlet is not aligned with the direction of the branch outlet of the artery, reducing the competition between non-physiological reverse blood flow and the physiological ejection of blood from the heart. This reduces the reverse blood flow during VA-ECMO cannulation via the femoral artery, making it easier to reduce left ventricular afterload, reducing complications caused by increased afterload, and improving the survival rate of patients treated with VA-ECMO.

[0024] In addition, by embedding internal and external guide wires in the inner wall of the tube, the bending angle of the closed end and the arc-shaped part of the tube can be changed by pulling the guide wires during use, so as to achieve fine and precise control of the end of the tube, thereby achieving the effect of finely adjusting the blood flow direction and avoiding thrombosis caused by the direction of the branch outlet of the artery. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the arterial cannula used for VA-ECMO in Embodiment 1 of this utility model;

[0026] Figure 2 This is a schematic diagram of the arterial blood vessel model in Embodiment 1 of this utility model;

[0027] Figure 3 This is a schematic diagram of the structure of the VA-ECMO arterial cannula in use in Embodiment 1 of this utility model;

[0028] Figure 4 This is a schematic diagram showing the change in velocity of the blood vessel inlet (Inlet1) over time in Embodiment 1 of this utility model;

[0029] Figure 5 This is a schematic diagram of the mesh independence verification process during model building in Embodiment 1 of this utility model;

[0030] Figure 6 This is a schematic diagram of data simulation and acquisition during the model building process in Embodiment 1 of this utility model;

[0031] Figure 7 This is a schematic diagram of the arterial cannula used for VA-ECMO in Embodiment 2 of this utility model;

[0032] Figure 8 This is a schematic diagram of the internal structure of the arterial cannula used for VA-ECMO in Embodiment 2 of this utility model;

[0033] Figure 9 for Figure 8 A magnified structural diagram of position A in the middle.

[0034] Reference numerals: 1. Tube body; 11. Injection port; 12. Closed end; 2. Main body; 3. Arched part; 31. Outlet hole; 4. Inner guide wire; 5. Outer guide wire; 6. Traction part; 7. Traction knob; 71. Inner rudder; 72. Outer rudder; 8. Artery; 81. Vessel inlet; 82. Vessel outlet a; 83. Vessel outlet b; 84. Vessel outlet c; 85. Vessel outlet d; 86. Vessel outlet e. Detailed Implementation

[0035] To enable those skilled in the art to better understand this utility model, the present utility model will now be further described in conjunction with specific embodiments.

[0036] Example 1:

[0037] like Figure 1 As shown, this utility model provides an arterial cannula for VA-ECMO, including a tube body 1 with a fluid guiding cavity. One end of the tube body 1 is provided with an injection port 11 that communicates with the fluid guiding cavity, and the other end is a closed end 12. The tube body 1 includes a main body 2 and an arc-shaped part 3 connected to each other. The injection port 11 is located at the end of the main body 2, and the closed end 12 is located at the end of the arc-shaped part 3.

[0038] Furthermore, the main body 2 and the bow-shaped part 3 are connected in an integral structure.

[0039] The arc-shaped portion 3 is a curved arc shape adapted to the aortic arch, and it is provided with an outlet hole 31 that communicates with the fluid guide cavity. The outlet hole 31 is perpendicular to the plane where the arc-shaped portion 3 is located, and an outlet hole 31 is provided on at least one side of the arc-shaped portion 3. Specifically, there are a number of outlet holes 31, and they are evenly distributed along the tubing (arc-shaped arc) of the arc-shaped portion 3. The distance between adjacent outlet holes 31 is between 1 and 3 cm, and the diameter of the outlet hole 31 is between 1 and 3 mm.

[0040] Optionally, in some embodiments, liquid outlet holes 31 are provided on both sides of the arc-shaped portion 3.

[0041] The VA-ECMO arterial cannula provided in this embodiment increases the overall length of the cannula 1 compared to existing cannulas, so that the closed end 12 at the end of the arc-shaped part 3 can directly reach the aortic arch. At the same time, the original outlet at the end of the existing cannula is eliminated and set as the closed end 12, and an outlet hole 31 is provided on the side of the arc-shaped part 3.

[0042] This allows the blood outflow direction to be changed through the side-mounted fluid outlet 31 during VA-ECMO, directly supplying blood to the aortic arch branch vessels. This satisfies the blood and oxygen supply to the upper and lower body while reducing the competition between non-physiological reverse blood flow and the physiological ejection of blood from the heart. It also reduces the reverse blood flow during VA-ECMO cannulation via the femoral artery, making it easier to reduce left ventricular afterload, reduce complications caused by increased afterload, and improve the survival rate of patients treated with VA-ECMO.

[0043] Based on the above, it can be seen that the diameter and number of outlet holes 31, as well as the spacing between adjacent outlet holes 31, are variables that affect the overall load reduction effect of arterial cannulation. The following simulation experiment is conducted to simulate and verify the effects of the three variables of outlet holes 31.

[0044] Model building:

[0045] To better match the actual model, a three-dimensional model of artery 8 was created and simulated, combined with... Figure 2 and Figure 3 As shown; the simulation experiment set up three experimental groups: no ECMO arterial cannulation group (using only arterial vessel 8), control group (using traditional VA-ECMO arterial cannulation), and experimental group (using VA-ECMO arterial cannulation in Example 1).

[0046] Boundary condition settings:

[0047] In the artery vessel model 8, both the vessel inlet 81 and the infusion port 11 of the tube body 1 are velocity inlets, while the vessel outlets in the artery vessel model 8 are pressure outlets. To more closely resemble reality, the velocity of the vessel inlet 81 (Inlet1) is set to a dynamic velocity to simulate the cardiac cycle, with the velocity changing over time as follows: Figure 4 As shown. The flow rate of Inlet 2 (11) was set to 5 L / min, which is consistent with the flow rate of VA-ECMO in clinical practice. The flow field was laminar, and the flow field parameters were set to be consistent with the actual blood properties, namely, density of 1057 kg / cm3 and dynamic viscosity of 0.0037 kg / (m•s).

[0048] Grid generation:

[0049] To make the simulation results closer to reality, the boundary layer thickness was set to 0.006 mm, the mesh was refined at the model's inlet and outlet, and the model was verified to be mesh-independent. Figure 5 As shown, when the number of model grids exceeds 12 million, the number of grids has virtually no impact on the simulation results. Therefore, in this study, the number of grids in the simulation model was chosen to be 12 million.

[0050] Data collection:

[0051] To more closely approximate clinical indicators, the integral of pressure over time at the vessel inlet 81 (Inlet1) during the rapid ejection phase was statistically measured, representing the work done by pressure. For example... Figure 6 As shown, the integral area of ​​pressure over time during the rapid ejection phase is the physical quantity collected in the simulation, which corresponds to the work done by the heart per beat in clinical testing.

[0052] Orthogonal experiment:

[0053] To investigate the effects of the orifice diameter, spacing, and number of liquid inlets 31 on the decompression effect and to optimize these parameters, an orthogonal experimental design was conducted, and the decompression results of each group were statistically analyzed. It should be noted that in the arterial vessel 8 model used in this experiment, the diameter of vessel inlet 81 (Inlet1) is 27 mm, the diameter of injection port 11 (Inlet2) is 4 mm, the diameter of vessel outlet a82 (Outlet1) is 10 mm, the diameter of vessel outlet b83 (Outlet2) is 7 mm, the diameter of vessel outlet c84 (Outlet3) is 6 mm, the diameter of vessel outlet d85 (Outlet4) is 10.4 mm, and the diameter of vessel outlet e86 (Outlet5) is 10.3 mm. Specific experimental results are shown in Table 1.

[0054] Table 1. Orthogonal experimental design and statistical results

[0055] Group Aperture (mm) Spacing (mm) quantity Work done (Pa·s) Pressure reduction rate (%) 1 1 10 1 413.96 50.9 2 1 15 3 435.17 34.9 3 1 20 5 404.15 58.2 4 1 25 2 392.78 66.8 5 1 30 4 415.64 49.6 6 1.5 10 5 407.40 55.8 7 1.5 15 2 437.66 33.1 8 1.5 20 4 414.00 50.8 9 1.5 25 1 397.42 63.3 10 1.5 30 3 423.26 43.9 11 2 10 4 416.68 48.8 12 2 15 1 461.95 14.8 13 2 20 3 428.46 40.0 14 2 25 5 415.48 49.7 15 2 30 2 430.96 38.1 16 2.5 10 3 420.88 45.7 17 2.5 15 5 417.97 47.8 18 2.5 20 2 426.19 41.7 19 2.5 25 4 413.81 51.0 20 2.5 30 1 441.40 30.3 21 3 10 2 427.48 40.7 22 3 15 4 421.48 45.2 23 3 20 1 454.32 20.6 24 3 25 3 417.47 48.2 25 3 30 5 424.60 42.9 Non-arterial cannulation group 348.50 control group 481.70

[0056] As shown in the table above, the cardiac work in the non-ECMO arterial cannula was 348.5 Pa·s, while that in the control group was 481.7 Pa·s. The increase in cardiac work was 133.2 Pa·s, representing an increase of 38.2%. In the orthogonal experiment, decompression was achieved in almost all protocols, with the maximum decompression rate reaching 66.8%.

[0057] Example 2:

[0058] In embodiment 2 of this utility model, using Figures 7-9 The following description will be provided. Furthermore, descriptions of parts that are no different from those in Embodiment 1 will be omitted, and the same reference numerals will be used instead.

[0059] like Figure 7 , Figure 8 , Figure 9As shown, the VA-ECMO arterial cannula of this utility model includes a cannula 1 with an inner traction guide wire 4 and an outer traction guide wire 5 that are movably embedded in its wall. One end of the inner traction guide wire 4 and the outer traction guide wire 5 is fixedly connected to the closed end 12 of the cannula 1, and the other end is a movable end. The angle of the arc-shaped part 3 can be changed by pulling the movable end of the inner traction guide wire 4 or the outer traction guide wire 5.

[0060] For details, please refer to Figure 8 and Figure 9 As shown, the inner guide wire 4 has an end near the closed end 12 of the tube body 1 that is in an arc shape that matches the arc shape 3, and it is arranged on the inner arc side near the arc shape 3; the outer guide wire 5 has an end near the closed end 12 of the tube body 1 that is in an arc shape that matches the arc shape 3, and it is arranged on the outer arc side near the arc shape 3.

[0061] Furthermore, such as Figure 7 As shown, the tube body 1 also includes a traction part 6 connected to the main body 2. The traction part 6 is provided with a traction knob 7 movably connected to it. The movable ends of the inner traction guide wire 4 and the outer traction guide wire 5 are both fixedly connected to the traction knob 7. Specifically, the traction knob 7 is provided with symmetrically distributed inner rudder 71 and outer rudder 72. The inner rudder 71 is fixedly connected to the movable end of the inner traction guide wire 4, and the outer rudder 72 is fixedly connected to the movable end of the outer traction guide wire 5. During use, the inner traction guide wire 4 or the outer traction guide wire 5 can be pulled by rotating the traction knob 7 to change the bending angle of the bow-shaped part 3.

[0062] It should be noted that during actual use, the position of the arc-shaped part 3 and the outlet hole 31 can be adjusted by real-time detection and observation using external imaging to avoid the outlet hole 31 being aligned with the branch outlet of the arterial vessel 8, thereby reducing the probability of thrombosis.

[0063] In summary, the arterial cannula for VA-ECMO provided by this utility model reduces the reverse blood flow in VA-ECMO via the femoral artery by setting one end of the cannula as a closed end and changing the blood flow direction through the outlet hole. This makes it easier to reduce left ventricular afterload, reduce complications caused by increased afterload, and improve the survival rate of patients treated with VA-ECMO.

[0064] The above are merely preferred embodiments of the present utility model and do not limit the patent scope of the present utility model. All equivalent changes and modifications made within the scope of the present utility model shall still fall within the scope of the present utility model.

Claims

1. An arterial cannula for VA-ECMO, characterized in that: It includes a tube (1) with a liquid guiding cavity, one end of which is provided with an injection port (11) connected to the liquid guiding cavity, and the other end is a closed end (12). The tube body (1) includes a main body (2) and an arc-shaped part (3) connected to each other. The injection port (11) is located at the end of the main body (2), and the closed end (12) is located at the end of the arc-shaped part (3). The bow-shaped portion (3) is a curved bow shape adapted to the aortic arch, and it is provided with an outlet hole (31) that communicates with the fluid guiding cavity.

2. The arterial cannula for VA-ECMO according to claim 1, characterized in that: The liquid outlet (31) is perpendicular to the plane of the arc-shaped part (3), and the liquid outlet (31) is provided on at least one side of the arc-shaped part (3).

3. The arterial cannula for VA-ECMO according to claim 1, characterized in that: The diameter of the liquid outlet (31) is between 1 and 3 mm.

4. The arterial cannula for VA-ECMO according to claim 1, characterized in that: The liquid outlet (31) is provided in several parts, and is evenly distributed along the pipeline of the arc-shaped part (3).

5. The arterial cannula for VA-ECMO according to claim 4, characterized in that: The distance between adjacent liquid outlet holes (31) is between 1 and 3 cm.

6. The arterial cannula for VA-ECMO according to claim 1, characterized in that: The tube (1) is provided with an inner guide wire (4) and an outer guide wire (5) that are movably embedded in its tube wall. One end of the inner guide wire (4) and the outer guide wire (5) are fixedly connected to the closed end (12) of the tube (1), and the other end extends movably out of the tube (1).

7. The arterial cannula for VA-ECMO according to claim 6, characterized in that: The inner guide wire (4) is in an arc shape that is adapted to the arc-shaped part (3) at one end near the closed end (12) of the tube body (1), and is arranged near the inner arc side of the arc-shaped part (3). The outer guide wire (5) is in an arc shape that matches the arc-shaped part (3) at one end near the closed end (12) of the tube body (1), and is arranged on the outer arc side near the arc-shaped part (3).

8. The arterial cannula for VA-ECMO according to claim 7, characterized in that: The tube body (1) also includes a traction part (6) connected to the main body (2), and the traction part (6) is provided with a traction knob (7) movably connected thereto. The movable ends of the inner traction guide wire (4) and the outer traction guide wire (5) are fixedly connected to the traction knob (7).

9. The arterial cannula for VA-ECMO according to claim 8, characterized in that: The traction knob (7) is provided with symmetrically distributed inner rudder (71) and outer rudder (72). The inner rudder (71) is fixedly connected to the movable end of the inner traction guide wire (4), and the outer rudder (72) is fixedly connected to the movable end of the outer traction guide wire (5).

10. The arterial cannula for VA-ECMO according to claim 1, characterized in that: The main body (2) and the bow-shaped part (3) are connected in an integral structure.

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