Procedure simulator

Abstract

A procedure simulator (10) comprises: an animal heart (12); a living lung reproduction module (14) that is connected to the heart (12), has a pump (52) and an artificial lung (24), adds oxygen to blood discharged from the heart (12), and sends the blood to the heart (12); and a cell metabolism reproduction module (16) that is connected to the heart (12) and has a deoxygenation unit (64) that deoxygenates the blood discharged from the heart (12). The procedure simulator sends the blood deoxygenated by the deoxygenation unit (64) to the heart (12).

Description

Procedure Simulator

[0001] The present disclosure relates to a procedure simulator.

[0002] In open-heart surgery for severe cardiovascular disease, an artificial heart-lung machine (extracorporeal circulation machine) is used to artificially replace the functions of the living body's heart and lungs. Japanese Patent No. 4999186 discloses a training device for an artificial heart-lung machine as a conventional technique for learning how to deal with various problems that may arise in clinical settings using an artificial heart-lung machine.

[0003] Patent No. 4999186

[0004] The above-mentioned conventional techniques do not allow efficient training of the introduction, management, and weaning of a living body from an artificial heart-lung machine.

[0005] The present disclosure aims to solve the above-mentioned problems.

[0006] (1) An aspect of the present disclosure is a procedural simulator used for training in the introduction, management, and removal of an artificial heart-lung machine from a living organism, comprising: an animal's heart; a living lung reproduction module connected to the heart, having a pump and an artificial lung, adding oxygen to blood leaving the heart and sending the blood to the heart; and a cellular metabolism reproduction module connected to the heart, having a deoxygenation unit that deoxygenates the blood leaving the heart, and the blood deoxygenated by the deoxygenation unit is sent to the heart.

[0007] This configuration, which includes a living body lung reproduction module and a cellular metabolism reproduction module, allows for realistic reproduction (simulation) of blood circulation and oxygen consumption in the living body, thereby enabling efficient training in the introduction, management, and weaning of the heart-lung machine to the living body.

[0008] (2) In the procedure simulator described in the above item (1), the living lung reproduction module may have a reservoir for storing the blood.

[0009] With this configuration, the lung reproduction module has a reservoir, making it possible to reproduce the volume of the living body, thereby providing a realistic situation closer to that of actual cardiac surgery, further enhancing the effectiveness of training.

[0010] (3) In the procedure simulator described in the above item (2), the reservoir may be disposed below the heart.

[0011] With this configuration, blood coming out of the heart can be smoothly sent to the reservoir.

[0012] (4) In the procedure simulator described in any one of items (1) to (3) above, the deoxygenation unit may be an artificial lung that deoxygenates the blood discharged from the heart.

[0013] According to this configuration, by using an artificial lung, a cell metabolism reproduction module that deoxygenates blood can be easily constructed.

[0014] (5) In the procedure simulator described in any one of items (1) to (3) above, the cell metabolism reproduction module has a venous blood line that leads venous blood, which is the blood deoxygenated by the deoxygenation unit, to the heart, and the venous blood line may be provided with a fluid resistor that reduces the pressure of the venous blood below that of arterial blood, which is the blood flowing in the aorta extending from the heart.

[0015] This configuration allows for realistic reproduction of blood circulation in a living body by reproducing relatively high-pressure arterial blood and relatively low-pressure venous blood, thereby enabling realistic reproduction of the differences in bleeding patterns when cannulating the heart.

[0016] (6) In the procedure simulator described in any one of items (1) to (3) above, the cellular metabolism reproduction module has a venous blood line that leads venous blood, which is the blood deoxygenated by the deoxygenation unit, to the heart, and the superior vena cava and the inferior vena cava extend from the heart, and the venous blood line may have a first branch line connected to the superior vena cava and a second branch line connected to the inferior vena cava.

[0017] With this configuration, venous blood flows into the heart via the superior vena cava and the inferior vena cava, making it possible to realistically reproduce the flow of blood flowing into the heart.

[0018] According to the present disclosure, since the in vivo lung reproduction module and the cellular metabolism reproduction module are provided, it is possible to realistically reproduce (simulate) blood circulation and oxygen consumption in the living body, thereby enabling efficient training in the introduction, management, and weaning of the heart-lung machine to the living body.

[0019] FIG. 1 is a schematic diagram showing an artificial heart-lung machine and a procedure simulator according to an embodiment of the present invention.

[0020] 1 is used for training in the introduction, management, and removal of an artificial heart-lung machine 100 from a living body. The artificial heart-lung machine 100 is a system also known as an extracorporeal circulation device, and is used to artificially perform the functions of the heart 12 and lungs of a living body in open-heart surgery treatment for severe cardiovascular disease.

[0021] "Introduction of the heart-lung machine 100 into a living body" refers to cannulation, in which the blood infusion cannula 102 and the blood removal cannula 104 are placed in the living body, and the extracorporeal circulation of blood is established. In the following explanation, "introduction of the heart-lung machine 100" is synonymous with "establishment of extracorporeal circulation." "Removal of the heart-lung machine 100 from a living body" refers to decanulation, in which the blood infusion cannula 102 and the blood removal cannula 104 are removed from the living body. In the following explanation, "removal of the heart-lung machine 100" is synonymous with "removal of the extracorporeal circulation."

[0022] The procedure simulator 10 includes an animal (non-human animal) heart 12, a living lung reproduction module 14, and a cellular metabolism reproduction module 16. The heart 12 is used as a simulated human heart. Extending from the heart 12 are an aorta 30, a pulmonary artery 32, a superior vena cava 34, and an inferior vena cava 36. The brachiocephalic artery 15a, a left common carotid artery 15b, and a left subclavian artery 15c are occluded by appropriate occlusion mechanisms (such as clamps). The heart 12 may be excised from an animal, or may be frozen and stored until use and thawed before use.

[0023] The heart 12 may be, for example, a mammalian heart. In particular, a pig heart is suitable as the training heart 12 because its structure and size are relatively similar to those of a human heart. Furthermore, pig hearts are relatively inexpensive and easy to obtain. However, the heart 12 may also be a heart from a mammal other than a pig (for example, a heart from a cow, goat, sheep, etc.).

[0024] The living lung reproduction module 14 is a mechanism that generates blood with a high oxygen concentration (arterial blood) by performing gas exchange for oxygenation on blood (venous blood) discharged from the heart 12, and sends the venous blood to the heart 12. The living lung reproduction module 14 is a mechanism that simulates human lungs and the beating of the human heart. The blood used is blood collected from an animal. When a pig heart is used as the heart 12, it is preferable to use pig blood. Note that the heart 12 and the blood may come from different animals.

[0025] The living lung reproduction module 14 is connected to the heart 12. The living lung reproduction module 14 has a venous blood line 18, a reservoir 20, a pump system 22, an oxygenator 24, and an arterial blood line 26. Hereinafter, the oxygenator 24 will also be referred to as the "first oxygenator 24." The venous blood line 18 will also be referred to as the "first venous blood line 18." The arterial blood line 26 will also be referred to as the "first arterial blood line 26." The first venous blood line 18 is a tube for sending venous blood, which is blood discharged from the heart 12, to the reservoir 20. The upstream end of the first venous blood line 18 is connected to the pulmonary artery 32.

[0026] A bypass tube 40 is connected to the first venous blood line 18. The bypass tube 40 is connected to a first relay tube 42 that is connected to the outlet of the reservoir 20. An openable and closable clamp 44 is provided on the bypass tube 40. Note that blood is sent to the pump system 22 via the bypass tube 40 only when blood circulation by the living lung replica module 14 begins (during setup). Once blood circulation by the living lung replica module 14 has stabilized, the bypass tube 40 is closed by the clamp 44. Thereafter, blood is transferred from the reservoir 20 to the pump system 22 via the first relay tube 42.

[0027] The reservoir 20 is a blood storage container for temporarily storing venous blood, which is blood discharged from the heart 12. The capacity of the reservoir 20 is, for example, 1000 mL to 4000 mL, and more preferably 1500 mL to 3000 mL. The capacity of the reservoir 20 represents the amount of blood in a human, and thereby makes it possible to reproduce the volume of the living body.

[0028] Blood is introduced into the reservoir 20 via the first venous blood line 18. The reservoir 20 is positioned vertically below a position (e.g., an operating table) where the heart 12 is placed. This allows blood from the heart 12 to be smoothly delivered to the reservoir 20. Note that FIG. 1 is a schematic diagram of the configuration of the procedure simulator 10, and therefore the heart 12, shown by a solid line, does not show its vertical positional relationship with the reservoir 20. For convenience, therefore, FIG. 1 expresses the height difference L between the heart 12 and the reservoir 20 in terms of the relationship between the heart 12, shown by a virtual line, and the reservoir 20, shown by a solid line. Here, the position P1 of the heart 12 is the lower end position of the heart 12 when the heart 12 is positioned. The position P2 of the reservoir 20 is the upper end position of the reservoir 20. The vertical position P2 of the reservoir 20 is the same as the downstream end position of the first venous blood line 18. The height difference L is set to, for example, 300 mm to 700 mm.

[0029] A blood recovery line 46 is connected to the reservoir 20. A suction port 46a of the blood recovery line 46 is disposed near the periphery of the heart 12 (a region corresponding to the surgical field). An appropriate pump 48 is disposed on the blood recovery line 46. When blood flows out of the heart 12 during cardiac surgery training, the blood recovery line 46 can be used to suck blood from the region corresponding to the surgical field around the heart 12 and return the blood to the reservoir 20.

[0030] The pump system 22 is connected to the reservoir 20 via a first relay tube 42. A flow rate adjusting member 50 is attached to the first relay tube 42. The flow rate adjusting member 50 is, for example, a clip that can change the cross-sectional area of ​​the flow path within the first relay tube 42 by clamping the first relay tube 42. The flow rate adjusting member 50 can adjust the amount of blood stored in the reservoir 20.

[0031] The pump system 22 includes a pump 52, a drive unit 54, and a control unit 55. The inlet of the pump 52 is connected to the downstream end of the first relay tube 42. The pump 52 is, for example, a centrifugal pump 52A. A pump other than the centrifugal pump 52A may also be used as the pump 52. The pump 52 draws blood from the reservoir 20 and sends the blood toward the first oxygenator 24.

[0032] The drive unit 54 has a motor 56 for driving the pump 52. The operation (rotational speed) of the motor 56 is controlled by the control unit 55. The control unit 55 operates the pump 52 to simulate the beating of a human heart. Specifically, the drive unit 54 operates so that the pump 52 repeatedly starts and stops. This causes pressure fluctuations in the blood being pumped toward the heart 12, causing the heart 12 to bend.

[0033] The first oxygenator 24 is connected to the pump system 22 (the outlet of the pump 52) via a second relay tube 58. The first oxygenator 24 performs gas exchange with the blood (oxygenation of the blood). That is, the first oxygenator 24 adds oxygen to the blood. Oxygen gas is supplied to the first oxygenator 24 from an oxygen supply unit 25 (e.g., an oxygen cylinder). The first oxygenator 24 converts the blood into arterial blood with a high oxygen concentration and a low carbon dioxide concentration. For example, a hollow fiber membrane oxygenator is used as the first oxygenator 24.

[0034] First arterial blood line 26 is a tube for sending blood oxygenated by oxygenator 24 to heart 12. The downstream end of first arterial blood line 26 is connected to left atrium 12a of heart 12. Therefore, blood introduced into left atrium 12a flows into aorta 30 via left ventricle 12b. Alternatively, the downstream end of first arterial blood line 26 may be connected to left ventricle 12b of heart 12.

[0035] A first heating mechanism 60 is connected to the first oxygenator 24. The first heating mechanism 60 supplies a heating liquid (e.g., hot water) to the first oxygenator 24. Heat exchange occurs between the heating liquid and the blood inside the first oxygenator 24, so that the blood flowing through the first oxygenator 24 is heated to a temperature close to that of human blood.

[0036] The cellular metabolism reproduction module 16 is a mechanism that generates venous blood with a low oxygen concentration by performing gas exchange for deoxygenation on arterial blood discharged from the heart 12 and sends the venous blood to the heart 12. In other words, the cellular metabolism reproduction module 16 is a mechanism that simulates human cells and reproduces oxygen consumption in a living body. The cellular metabolism reproduction module 16 is connected to the heart 12. The cellular metabolism reproduction module 16 has an arterial blood line 62, a deoxygenation unit 64, and a venous blood line 66. Hereinafter, the arterial blood line 62 will also be referred to as the "second arterial blood line 62." The venous blood line 66 will also be referred to as the "second venous blood line 66."

[0037] The second arterial blood line 62 is a tube for transmitting arterial blood discharged from the heart 12 to the deoxygenation unit 64. The upstream end of the second arterial blood line 62 is connected to the aorta 30. The downstream end of the second arterial blood line 62 is connected to the deoxygenation unit 64. The deoxygenation unit 64 may be configured as an oxygenator 68 (hereinafter also referred to as the "second oxygenator 68") that deoxygenates the blood discharged from the heart 12. An exchange gas (e.g., carbon dioxide gas and nitrogen gas) for deoxygenation is supplied to the second oxygenator 68 from a gas supply unit 69. The blood introduced into the second oxygenator 68 has a high oxygen concentration, while the exchange gas does not contain oxygen gas. As the blood passes through the second oxygenator 68, oxygen moves from a high oxygen concentration to a low oxygen concentration via the gas exchange membrane, so that the blood is converted by the second oxygenator 68 into venous blood with a low oxygen concentration.

[0038] A second heating mechanism 70 is connected to the second oxygenator 68. The second heating mechanism 70 supplies a heating liquid (e.g., warm water) to the second oxygenator 68. Heat exchange occurs between the heating liquid and the blood inside the second oxygenator 68, so that the blood flowing through the second oxygenator 68 is heated to a temperature close to that of human blood. The first heating mechanism 60 and the second heating mechanism 70 may be a common heating mechanism. Either the first heating mechanism 60 or the second heating mechanism 70 may be omitted.

[0039] The second venous blood line 66 is a tube for conducting venous blood, which is blood deoxygenated by the deoxygenation unit 64, to the heart 12. The second venous blood line 66 has a main line 72, a first branch line 74, and a second branch line 76. The upstream end of the main line 72 is connected to the outlet of the deoxygenation unit 64. The first branch line 74 branches off from the downstream end of the main line 72 and is connected to the superior vena cava 34. The second branch line 76 branches off from the downstream end of the main line 72 and is connected to the inferior vena cava 36.

[0040] A branching member 78 is provided at the downstream end of the main line 72. The branching member 78 is, for example, a Y-shaped pipe. The branching member 78 is a fluid resistor 80. The fluid resistor 80 reduces the pressure of the venous blood sent to the heart 12 below the pressure of the arterial blood flowing through the aorta 30. The fluid resistor 80 has an inlet port 82 connected to the main line 72, a first outlet port 84a connected to the first branch line 74, and a second outlet port 84b connected to the second branch line 76. The flow path cross-sectional areas of the first outlet port 84a and the second outlet port 84b are each smaller than the flow path cross-sectional area of ​​the main line 72. Therefore, the fluid resistor 80 acts as a throttle valve, and the pressure of the blood decreases as the blood passes through the fluid resistor 80. This allows the reduced-pressure blood to be sent to the heart 12.

[0041] Using the procedure simulator 10, training in the introduction, management, and removal of the artificial heart-lung machine 100 from a living body can be performed as follows.

[0042] A typical heart-lung machine 100 is generally configured as follows.

[0043] The heart-lung machine 100 includes a blood reservoir 106, a centrifugal pump 108, and a gas exchanger 110. The blood reservoir 106 is a container for temporarily storing blood removed from the heart 12. Blood (venous blood) is introduced into the blood reservoir 106 via a blood removal cannula 104 and a blood removal line 112. A blood return line 130 is connected to the blood reservoir 106. A suction port 130a of the blood return line 130 is disposed near the periphery of the heart 12 (a region corresponding to the surgical field). An appropriate pump 132 is disposed on the blood return line 130. During cardiac surgery training, if blood flows out of the heart 12, the blood return line 130 can be used to aspirate blood from the region corresponding to the surgical field around the heart 12 and return it to the blood reservoir 106. The centrifugal pump 108 aspirates blood from the blood reservoir 106 and delivers it toward the gas exchanger 110. The centrifugal pump 108 is driven to rotate by a drive unit 116 having a motor 114. The gas exchange unit 110 is an artificial lung that performs gas exchange (oxygenation) on the blood. The gas exchange unit 110 converts the blood into arterial blood with a high oxygen concentration and a low carbon dioxide concentration. The blood to which oxygen has been added by the gas exchange unit 110 is sent to the aorta 30 via a blood sending line 118 and the blood sending cannula 102.

[0044] In the procedure simulator 10 configured as described above, the living lung reproduction module 14 reproduces the oxygenation of blood by the human lungs and the beating of the human heart, while the cellular metabolism reproduction module 16 reproduces the oxygen consumption by cells in the human body (the production of venous blood).

[0045] In order to establish (introduce) extracorporeal circulation in this state, the trainee first places the blood transfer cannula 102. Specifically, a part of the aorta 30 is incised to form an insertion opening, and the blood transfer cannula 102 is inserted into the aorta 30 through the insertion opening. Because the arterial blood pressure is reproduced within the aorta 30, when the insertion opening is formed in the aorta 30, blood flows out vigorously from the incision site. The trainee can experience this process realistically.

[0046] The trainee connects the blood transfer cannula 102 inserted into the aorta 30 to the blood transfer line 118, which is the blood circuit of the heart-lung machine 100, via the first connector 120. This connects the heart-lung machine 100 and the heart 12. The trainee removes the clamp from the blood transfer line 118 and confirms that the transfer pressure fluctuates in synchronization with the arterial pressure. Thereafter, the trainee sends a small amount of filling fluid into the blood transfer line 118 while monitoring the transfer pressure, and confirms whether blood can be sent to the heart 12.

[0047] Next, the trainee places the blood removal cannula 104. Specifically, to insert the blood removal cannula 104 into the right atrium 12c, superior vena cava 34, or inferior vena cava 36, ​​a part of the relevant area is incised to form an insertion opening, and the blood removal cannula 104 is inserted through the insertion opening. FIG. 1 shows an example of placing the blood removal cannula 104 in the right atrium 12c and inferior vena cava 36. Because the blood pressure of venous blood is reproduced inside the heart 12, the force of blood flowing out of the incision site when it is made is smaller than when the aorta 30 is incised. The trainee can experience this process realistically.

[0048] Next, the trainee connects the blood removal cannula 104 to the blood removal line 112, which is the blood circuit of the heart-lung machine 100, via the second connector 122. This starts extracorporeal circulation. The trainee then inserts a cannula for injecting cardioplegia solution from the aortic root 30a and the left heart vent cannula into the target locations. Furthermore, before connecting the left heart vent cannula to the vent circuit, the trainee performs a vent test to confirm that vent suction is possible.

[0049] Thereafter, cardiac arrest due to the injection of cardioplegia is simulated by stopping the pump system 22 of the living lung simulation module 14. With the heart 12 in a state of cardiac arrest, the trainee clamps the aortic root 30a using a clamp (aortic clamp). Completion of aortic clamping establishes extracorporeal circulation.

[0050] The liquid used in the procedure simulator 10 is not a liquid colored with a coloring agent or the like, but animal blood containing hemoglobin. Therefore, when blood passes through the gas exchange section 110 in the oxygenator 100, oxygen binds to the hemoglobin in the blood, causing the blood to change color from dark red to bright red. Because each component of the oxygenator 100 is transparent, the discoloration of the blood is visible to the trainee, improving realism.

[0051] Weaning from extracorporeal circulation can be done by reversing the procedure used for induction, allowing trainees to efficiently train in weaning from extracorporeal circulation in a realistic environment that closely resembles actual clinical practice.

[0052] The procedure simulator 10 according to this embodiment has the following advantages.

[0053] This procedure simulator 10 includes a living lung reproduction module 14 and a cellular metabolism reproduction module 16, allowing it to realistically reproduce (simulate) blood circulation and oxygen consumption in the living body during extracorporeal circulation. This allows trainees to learn how to adjust the oxygen supply balance during extracorporeal circulation. This allows for efficient training in the introduction, management, and weaning of the heart-lung machine 100 to a living body.

[0054] This procedure simulator 10, which includes a living lung reproduction module 14 and a cellular metabolism reproduction module 16, allows training in surgical procedures for introducing, managing, and weaning extracorporeal circulation. That is, it allows training in cannulation (placement of the blood infusion cannula 102 and the blood drainage cannula 104), decannulation (removal of the blood infusion cannula 102 and the blood drainage cannula 104), aortic clamping, and special extracorporeal circulation (e.g., isolated cerebral extracorporeal circulation).

[0055] In extracorporeal circulation, the blood volume in the living body is adjusted by changing the blood supply flow rate and the blood drainage flow rate. This is because excessively increasing the blood volume in the living body during cardiac surgery increases the burden on the surgical site. By using this procedure simulator 10, students can learn about blood volume control during the introduction, management, and withdrawal of extracorporeal circulation.

[0056] It also becomes possible to train using a cardiac surgery blood monitor that continuously measures the oxygen concentration, pH, temperature, etc. in the patient's blood during surgery.

[0057] To avoid placing a heavy burden on the living body when establishing extracorporeal circulation, it is important to smoothly manage the positions of various cannulas, the treatment of the insertion site, and to communicate smoothly with the operator of the heart-lung machine 100, the surgeon, and other trainees. By using the procedure simulator 10, trainees can learn not only surgical procedures in the process of establishing extracorporeal circulation, but also comprehensively, including the experience of communication between trainees.

[0058] Furthermore, it is also possible to learn how to respond to accidents during extracorporeal circulation. For example, an accident during extracorporeal circulation may occur when a large amount of air bubbles are continuously sent to the patient. By recreating such an accident, it is possible to efficiently experience and train the surgical procedures and treatments of the artificial heart-lung machine 100 required to resolve the problem.

[0059] The procedure simulator 10 also provides the following advantages.

[0060] The lung reproduction module 14 has a reservoir 20, which allows reproduction of the volume of the living body. This provides a realistic situation that is closer to that of an actual cardiac surgery, further enhancing the effectiveness of the training.

[0061] Since the deoxygenation unit 64 is an artificial lung 68 that deoxygenates the blood coming out of the heart 12, the cell metabolism reproduction module 16 that deoxygenates the blood can be easily constructed.

[0062] The venous blood line 66 of the cell metabolism reproduction module 16 is provided with a fluid resistor 80 that reduces the pressure of the venous blood below that of the arterial blood flowing through the aorta 30. With this configuration, relatively high pressure arterial blood and relatively low pressure venous blood are reproduced, thereby realistically reproducing the blood circulation of a living body. This makes it possible to realistically reproduce the difference in bleeding patterns when cannulating the heart 12.

[0063] The venous blood line 66 of the cellular metabolism reproduction module 16 has a first branch line 74 connected to the superior vena cava 34 and a second branch line 76 connected to the inferior vena cava 36. With this configuration, venous blood flows into the heart 12 via the superior vena cava 34 and the inferior vena cava 36, ​​making it possible to realistically reproduce the flow of blood flowing into the heart 12.

[0064] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments.

Claims

1. A procedural simulator used for training in the introduction, management, and removal of an artificial heart-lung machine from a living organism, comprising: an animal's heart; a living lung reproduction module connected to the heart, having a pump and an artificial lung, and adding oxygen to blood leaving the heart and sending the blood to the heart; and a cellular metabolism reproduction module connected to the heart, having a deoxygenation unit that deoxygenates the blood leaving the heart, wherein the blood deoxygenated by the deoxygenation unit is sent to the heart.

2. A procedure simulator according to claim 1, wherein the living lung reproduction module has a reservoir for storing the blood.

3. A procedure simulator according to claim 2, wherein the reservoir is disposed below the heart.

4. A procedure simulator according to any one of claims 1 to 3, wherein the deoxygenation unit is an artificial lung that deoxygenates the blood discharged from the heart.

5. A procedure simulator according to any one of claims 1 to 3, wherein the cell metabolism reproduction module has a venous blood line that leads venous blood, which is the blood deoxygenated by the deoxygenation unit, to the heart, and the venous blood line is provided with a fluid resistor that reduces the pressure of the venous blood below that of arterial blood, which is the blood flowing in the aorta extending from the heart.

6. A procedure simulator according to any one of claims 1 to 3, wherein the cellular metabolism reproduction module has a venous blood line that leads venous blood, which is the blood deoxygenated by the deoxygenation unit, to the heart, from which extend the superior vena cava and the inferior vena cava, and the venous blood line has a first branch line connected to the superior vena cava and a second branch line connected to the inferior vena cava.

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