GAS EXCHANGE UNIT

Description

[0001] The invention relates to a gas exchange unit and a method for producing a gas exchange unit. BACKGROUND OF THE INVENTION

[0002] In patients with life-threatening lung disease, lung function can be maintained using an artificial lung (oxygenator or gas exchange unit) until the lungs recover and natural lung function returns. In this case, blood is removed from the patient through an extracorporeal circuit and returned after treatment in the oxygenator.

[0003] Most known oxygenators were developed during the development of heart-lung machines for use during cardiac surgery lasting a few hours and are generally not optimized for long-term use. In contrast, the duration of use for lung support is often significantly longer and can last several weeks. Prolonged use of a known oxygenator can, for example, lead to hemolysis and thrombus formation due to suboptimal flow guidance with high flow resistance and poorly washed areas. The exchange capacity of such oxygenators also decreases, so they must be replaced during therapy, which can lead to complications and even blood loss or severe anticoagulation.

[0004] Conventional oxygenators, for example, consist of stacked hollow fiber mats arranged at right angles to each other. The mats are embedded in four layers of potting compound at the edges using a centrifugal or spin-casting process, creating a square cross-sectional area through which the blood flows. To distribute the blood as evenly as possible across the fiber surface, conventional oxygenators use perforated distribution plates installed in the inlet and outlet areas of the oxygenator. One such oxygenator is described, for example, in WO 2017 / 211 460 A1.

[0005] Furthermore, WO 2016 / 177 476 A1 discloses a device for treating a biological fluid comprising a housing with a first chamber forming a cavity, which is designed to receive the fluid to be treated, and at least one gas exchange means which is arranged at least partially in the first chamber, wherein an inlet section for admitting the fluid to be treated into the first chamber is formed in a surface of the housing, wherein the inlet section is formed at an acute angle relative to the surface of the housing.

[0006] Furthermore, WO 2014 / 183 852 A1 discloses an oxygenator module for gas exchange between blood and a gas in an extracorporeal lung support system, with a plurality of layers of semi-permeable hollow fibers through which gas can flow, wherein the hollow fibers of one of the layers are aligned at a twist angle about a central longitudinal axis of the oxygenator module to the hollow fibers of another of the layers, with a potting which extends along the central longitudinal axis and in which the hollow fibers are fixed, wherein the potting defines a cavity extending along the central longitudinal axis, in which the hollow fibers are arranged and through which blood can flow in the direction of the central longitudinal axis, wherein the potting has a substantially circular inner surface which delimits the cavity radially outwards.

[0007] EP 0 378 168 A2 further discloses an artificial lung using hollow fiber membranes, and in particular an artificial lung comprising a cylindrical housing with hollow fiber membranes arranged therein, the cylindrical housing having a blood inlet opening arranged away from the longitudinal axis of the housing so that blood introduced into the housing from the blood inlet opening is swirled therein and air bubbles generated in the blood are reduced. SUMMARY OF THE INVENTION

[0008] The object of the present invention is to improve the flow guidance in an oxygenator so that the needs of medium to long-term lung support can be met in a simple manner.

[0009] The inventive solution to the problem is achieved by the features of the independent claims. Further developments of the invention emerge from the subclaims.

[0010] According to the invention, a gas exchange unit for enriching blood with oxygen and for removing carbon dioxide from the blood is specified, comprising hollow fiber mats, comprising a housing with an inlet housing, comprising an inlet for the blood, wherein the inlet is arranged eccentrically on the inlet housing and is inclined towards the inlet housing in such a way that the blood can be provided with rotation, and wherein suitable structures are arranged on the inner blood-conducting surface of the inlet housing in such a way that the flow of the blood flowing through can additionally be distributed as homogeneously as possible. In order to distribute the blood flow through the gas exchange unit as homogeneously as possible over the circular fiber surface and, in particular, to ensure sufficient flow through the edge region, the blood is provided with rotation through the eccentrically inclined inlet. The hollow fiber mats have a circular cross-sectional area.The inlet of the gas exchange unit is arranged acentrically in a further development of the fiber layers of the hollow fiber mats.

[0011] As described below, the measures according to the invention create a gas exchange unit in which the distribution plates are omitted and the flow of the fluid (especially blood) is distributed evenly over the fiber surface formed by the hollow fiber mats by other means or measures. The gas exchange unit according to the invention has a longer service life than known oxygenators. In addition, the probability of blood damage is low with the gas exchange unit described.

[0012] The hollow fiber mats of the gas exchange unit are made of hollow fibers. The gas exchange unit can comprise one or more hollow fiber mats. The fiber orientation of one fiber mat can be arranged at an angle to the fiber orientation of another fiber mat. By crossing the fiber mats, the gas exchange characteristics and blood flow can be improved.

[0013] The gas exchange unit is also known as an oxygenator. An oxygenator is a device that enriches blood with oxygen and removes carbon dioxide. Thus, the oxygenator can replace or support the lungs both in the short term and over longer periods.

[0014] In a further development, the gas exchange unit provides for the inlet to be located at the front of a housing of the gas exchange unit. The arrangement of the inlet at the front of the gas exchange unit enables a homogeneous flow through the hollow fiber mats. The housing of the gas exchange unit has an inlet housing.

[0015] According to a further development of the gas exchange unit, the inlet is connected to the inlet housing, whose surface has structures. Suitable structures on the inner blood-carrying surface of the inlet housing also distribute the flow as evenly as possible. The inlet is inclined if the angle between a central axis of the inlet and a plane formed by the inlet housing is greater than 0° and / or less than 90°.

[0016] In a further development of the gas exchange unit, the structures are arranged in a scoop-like, web-like, or cross-strut-like manner on the surface of the inlet housing. These scoop-like, web-like, or cross-strut-like structures allow for evenly distributed flow through or feeding the fiber surfaces in the gas exchange unit. The flow is uniform both in the inner and outer areas of the hollow fiber mats.

[0017] According to a further development of the gas exchange unit, the inlet is designed with a cross-sectional area that continuously widens in the flow direction, so that the flow velocity is reduced slowly and not abruptly. A ratio of dD / 2dL<1 between the diameter (dD) and the length (dL) of the inlet is advantageous. (In other words, the ratio between the radius of the inlet and the length of the inlet is less than 1.) This ratio changes over the length of the inlet. It can also change gradually in the inlet area.

[0018] According to a further development, the diameter expansion of the inlet over the length of the inlet is less than 45°.

[0019] According to a further development of the gas exchange unit, the cross-sectional area of ​​the inlet is designed to expand asymmetrically. This expansion can be asymmetrical to precisely direct the flow and thus distribute it evenly.

[0020] In a further development of the gas exchange unit, it is provided that the inlet has a cross-sectional area that is variable over the length of the inlet.

[0021] In a further development of the gas exchange unit, it is provided that the gas exchange unit has an outlet whose cross-sectional area decreases in the direction of flow. The fluid, in particular blood, is accelerated by this continuous decrease in cross-sectional area. A ratio between diameter expansion (dD) and flow length (dL) of less than 1 is advantageous: dD / dL < 1 or dD / 2dL.

[0022] According to another further development of the gas exchange unit, the gas exchange unit is provided with an outlet that includes a deflection. In order to create the most compact gas exchange unit possible, the flow of the fluid, particularly blood, is deflected at an angle on the outlet side. The deflection angle is approximately 90° or between 70° and 90°. Such deflections can lead to secondary vortices or flow separation of the fluid, particularly blood. However, by continuously decreasing the cross-sectional area of ​​the outlet, the fluid is accelerated, thus counteracting or virtually eliminating the formation of secondary vortices or flow separation.

[0023] According to a further development, the gas exchange unit or oxygenator comprises a venting device, in particular one arranged substantially centrally. Should air be sucked in, it collects in the center of the rotating flow, in particular in a cavity of the gas exchange unit, due to the inlet geometry formed by the inlet and inlet housing. There, the air is sucked out by the venting device. The venting device also serves as an outlet for air bubbles that can accumulate at these points during operation. During patient treatment, the venting devices can also be used for blood sampling. To prevent the formation of blood clots (thrombi), all areas of the venting device must be capable of being flushed, or it must be prevented that blood remains.

[0024] The venting device can be configured such that it can be selectively transferred into a first operating state, in which flushing of the venting device can be realized, or into a second operating state, in which venting of a cavity of the gas exchange unit can be realized. The venting device thus advantageously allows two technical functions to be realized: venting from the cavity and flushing and thus cleaning the venting device. Preferably, the venting device is flushed after a venting process. This prevents any blood residues that may have flowed out during a venting process from remaining in the venting device.Alternatively, the venting device can be switched to the first operating state, in which the cavity of the gas exchange unit is not vented, or to the second operating state, in which the cavity of the gas exchange unit is vented. In this configuration, the venting device can only perform one technical function, namely venting the cavity.

[0025] The gas exchange unit can include a vacuum source that can be fluidically connected to the venting device. By applying a vacuum to the venting device using the vacuum source, it can be easily ensured that the air in the cavity is removed.

[0026] In a further development of the gas exchange unit, the venting device is designed to include a flexible membrane. The central section of the inlet is made of a flexible material, allowing it to be inverted for venting purposes, thus creating a larger volume on the blood side to collect air bubbles.

[0027] The gas exchange unit may include an adjusting element that serves to switch the venting device between the first and second operating states. The adjusting element may be designed differently depending on the application, as described in more detail below.

[0028] The venting device can have a closing piston, which is moved into a first position to implement the first operating state or into a second position to implement the second operating state. The closing piston can be mounted for linear movement and / or rotation so that it can be moved from the first position to the second position or vice versa. In particular, the closing piston can be mounted for rotation about its longitudinal axis. Alternatively or additionally, the closing piston can be designed such that one piston section is moved relative to another piston section to move the closing piston from the first position to the second position.

[0029] The closing piston can have a fluid line which is not fluidically connected to the cavity in the first position of the closing piston and is fluidly connected to the cavity in the second position of the closing piston. Furthermore, the fluid line can be fluidly connected to a supply line for supplying a rinsing agent in the first position of the closing piston and not fluidly connected to the supply line in the second position of the closing piston. In the second position, the air in the cavity can be discharged from the cavity via the fluid line. In this embodiment, the closing piston can be rotatably mounted and the adjusting element can be designed such that the closing piston is rotated when the adjusting element is actuated. Preferably, the adjusting element can be connected to the closing piston in a rotationally fixed manner.

[0030] In a further development, a sealing ring of the venting device can be attached to the closing piston. Furthermore, the venting device can have a return element that is operatively connected to the closing piston in such a way that the return element pushes the closing piston from the second position into the first position. In this embodiment, the closing piston can be mounted for linear movement. The return element can be a spring, in particular a compression spring. To move the closing piston from the first position into the second position, a force, in particular a linear force, is exerted on the closing piston by means of the adjusting element. The adjusting element can be, for example, a syringe.

[0031] In a further development, the sealing piston can have a weakened portion designed such that, in the second position, the adjusting element passes through the sealing piston. In the first position of the sealing piston, the sealing piston can prevent air or blood from escaping from the cavity despite the weakened portion. The adjusting element can be a pipette with at least one opening at the section passing through the sealing piston. The air in the cavity can be discharged from the cavity via the opening and the adjusting element. The weakening of the sealing piston can be achieved by a cut in the sealing piston.

[0032] To further improve the gas exchange unit, a further development provides for the hollow fiber mats to be embedded in the gas exchange unit, and for the transition from the embedded hollow fiber mats to adjacent components to have angled transitions. The position of the transition from the free fibers to the embedded fibers (potting level) can be subject to inaccurate tolerances. The angled transitions provided to the adjacent blood-carrying components result in a smooth, bump-free, and therefore blood-friendly transition, even with different positions of the potting level. The angled transitions also greatly simplify the manufacturing process of the gas exchange unit, as tolerances over a wider range during production do not lead to quality losses. A further development of the gas exchange unit provides for the inlet housing to have stabilizers.To increase the stability of the intake housing during potting, the intake housing is equipped with stabilizers. These can be designed as webs or cross braces. During potting, where high temperatures and / or stresses can be reached, the intake geometry remains unchanged and remains essentially unchanged by temperature changes.

[0033] Typically, in conventional oxygenators, the hollow fibers are first sealed at the ends and then embedded with a polyurethane adhesive. This potting step is performed using a spin-coating process to prevent the fibers from sticking together in the later blood-carrying area due to capillary effects and to enable a defined transition between the potting compound and the free fibers. Subsequently, the fibers with the cured potting compound are cut open from the outside perpendicular to the fiber direction to later allow the gas to flow through the fibers. Typically, the potting step is performed at both ends of the fibers, resulting in two potting processes for oxygenators with parallel fiber arrangements or four potting processes for stacked fiber mats.

[0034] According to the invention, a method for manufacturing a gas exchange unit is provided. The method comprises: introducing the potting compound for embedding the fiber ends, wherein the introduction is carried out only once, and forming a cylindrical cavity in the central area of ​​the gas exchange unit.

[0035] The gas exchange unit according to the invention is manufactured from stacked hollow fiber mats. In the process for manufacturing a gas exchange unit, the potting compound for embedding the fiber ends is introduced into a centrifuge in a single step, creating a cylindrical cavity in the central region of the gas exchange unit, in which the hollow fibers come into contact with a fluid, particularly blood. The cylindrical cavity ensures a homogeneous flow through the fiber mats. This requires a uniform flow at the front of the cylindrical cavity. The selected design results in a gas exchange unit with low production costs due to a reduction in manufacturing steps, since the fibers are embedded in a single step. With commercially available gas exchange units, the fibers are embedded in two or even four time-consuming steps in a centrifuge.

[0036] Furthermore, with the described process, all components that come into contact with blood are joined in a single step. No further bonding is necessary.

[0037] In contrast, conventional oxygenators achieve homogeneous blood flow through fiber mats using distribution or diffuser plates, which selectively increase flow resistance to varying degrees, thereby distributing the blood flow. A disadvantage of this approach is that additional shear stress and irritation can damage the blood. Furthermore, thrombi can form on the back side of the distribution plates, where flow is obstructed, due to the potential for stagnant blood flow. The invention eliminates the need for such plates. SHORT DESCRIPTION OF THE CHARACTERS

[0038] Further details of the invention can be found in the exemplary embodiments described below with reference to the figures. They show: Figure 1 : an embodiment of a gas exchange unit, Figure 2 : another embodiment of a gas exchange unit, Figure 3 : the inlet housing made of Figure 2 , Figure 4 : an embodiment of a surface of an inlet housing, Figure 5 : a cross-sectional view of an inlet housing, Figure 6 : an embodiment of a venting device according to a first embodiment, Figure 7 : a perspective view of a venting device according to a further embodiment, Figure 8 : an enlarged view of a Figure 7 shown section, wherein the venting device is in a first operating state, Figure 9 : a sectional view of the Figure 8 shown section, Figure 10 : an enlarged view of a Figure 7 shown section, wherein the venting device is in a second operating state, Figure 11: a sectional view of the Figure 10 shown section, Figure 12 : a perspective view of a venting device according to a third embodiment, Figure 13 : an enlarged view of a Figure 12 shown section, wherein the venting device is in a first operating state, Figure 14 : a sectional view of the Figure 13 shown section, Figure 15 : an enlarged view of a Figure 12 shown section, wherein the venting device is in a second operating state, Figure 16 : a sectional view of the Figure 15 shown section, Figure 17 : a sectional view of a venting device according to a fourth embodiment, in which the venting device is in a first operating state, Figure 18: a sectional view of the venting device according to the fourth embodiment, in which the venting device is in a second operating state, Figure 19 : a sectional view of a venting device according to a fifth embodiment, in which the venting device is in a first operating state, Figure 20 : a sectional view of the venting device according to the fifth embodiment, in which the venting device is in a second operating state, Figure 21 : a sectional view of a venting device according to a sixth embodiment, in which the venting device is in a first operating state, Figure 22 : a sectional view of the venting device according to the sixth embodiment, in which the venting device is in a second operating state, Figure 23 : an embodiment of an outlet housing, Figure 24: a cross-sectional view of an outlet. DETAILED DESCRIPTION OF THE FIGURES

[0039] Exemplary embodiments of the invention are described below with reference to the accompanying drawings: Figure 1 shows an embodiment of a gas exchange unit 1, which comprises hollow fiber mats (not shown). The gas exchange unit 1 comprises an inlet 7, which is arranged eccentrically on an inlet housing 5. The inlet 7 is inclined towards the inlet housing 5. The inlet 7 is arranged on the end face of a housing of the gas exchange unit 1, which has the inlet housing 5, and enables a homogeneous flow through the hollow fiber mats. The inlet housing 5 forms an end face of the housing of the gas exchange unit 1. The inlet housing 5 is covered in its edge region by a housing part 3 of the gas exchange unit 1 (cf. e.g. Figure 1 ).

[0040] Figure 2shows a further embodiment of a gas exchange unit 1. The surface of the inlet housing 5 has structures 6, which additionally distribute the flow of blood flowing through the inner blood-carrying surface of the inlet housing 5 as homogeneously as possible. The inlet housing 5 can optionally be Figure 3 The stabilizers 8 shown in FIG. 1 can be designed as webs or cross struts. During potting, during which high temperatures and / or stresses can be reached, the inlet geometry of the inlet housing 5 is thus maintained and essentially does not change due to temperature changes and / or stresses.

[0041] Figure 3 shows the inlet housing 5 from Figure 2The eccentric, inclined arrangement of the inlet 7 is clearly visible. The structures 6, which distribute the flow homogeneously in the gas exchange unit 1, are designed as vane-shaped structures 6a and as web-shaped structures 6b. The structures 6 can also be arranged as cross struts on the surface of the inlet housing 5.

[0042] Through these structures 6, the flow through or feeding of the fiber surfaces of the hollow fiber mats in the gas exchange unit 1 can take place evenly in the inner, central area of ​​the hollow fiber mats as well as in the outer area, which includes an edge area of ​​the hollow fiber mats.

[0043] Figure 4 shows an exemplary embodiment of a structured surface of an inlet housing 5 in plan view. The different sizes of the blade-shaped structures 6a are visible. This ensures a uniform, homogeneous flow through the gas exchange unit 1.

[0044] Figure 5 shows a cross-sectional view of an inlet housing 5. This figure also shows the inclined position of the inlet 7 and the eccentric arrangement. The inlet housing 5 has the structures 6. The hollow fiber mats 32 are embedded in the gas exchange unit 1 and in contact with the inlet housing 5. In the contact area of ​​the hollow fiber mats 32 with the inlet housing 5, the inlet housing 5 has inclined transitions 9. The position of the respective transition 9 from the free fibers to the embedded 10 fibers (potting mirror) can be subject to inaccurate tolerances.

[0045] The sloping transitions 9 result in a smooth, shock-free and therefore blood-friendly transition even with different positions of the dilution mirror.

[0046] Figure 6shows an embodiment of a venting device 15. Should air be sucked in, it collects in the center of the rotating flow due to the inlet geometry formed by inlet 7 and inlet housing 5. There, the air is sucked out by the venting device 15. The venting device 15 also serves as an outlet for air bubbles. The venting device 15 comprises a vent pipe 19.

[0047] The venting device 15 comprises a flexible membrane 17. Part (A) of the Figure 6 shows the membrane 17 in a non-vented state. During venting, shown in part (B) of Figure 7, the membrane 17 is everted, creating an enlarged volume on the blood side to collect the air bubbles.

[0048] Figure 7shows a perspective view of a venting device 15 according to another embodiment of the present gas exchange unit. The venting device 15 is arranged adjacent to the inlet 7. The venting device 15 is also fluidly connected to a vacuum source 16 via a line 22. The vacuum source 16 is designed as a syringe.

[0049] Figure 8 shows an enlarged view of a Figure 7 The gas exchange unit 1 has an adjusting element 21 in the form of a rotary lever, by means of which the venting device 15 can be selectively transferred into a first operating state or into a second operating state. Figure 8 In the embodiment shown, the venting device is in the first operating state.

[0050] Figure 9 shows a sectional view of the Figure 8 shown section. As can be seen from Figure 9As can be seen, the venting device 15 has a sealing piston 18 which is rotationally fixed to the adjusting element 21. A fluid line 19 is provided in the sealing piston 18. In a Figure 8 In the first position of the closing piston 18 shown, the fluid line 19 is oriented such that it is not fluidically connected to the line 22. In this configuration, flushing the venting device is not possible.

[0051] Figure 10 also shows an enlarged view of a Figure 7 section shown. In the Figure 10 In the embodiment shown, the adjusting element 21 was rotated so that the venting device 15 is in the second operating state.

[0052] Figure 11 shows a sectional view of the Figure 10shown section. In the second operating state of the venting device 15, the closing piston 18 is arranged in a second position in which the fluid line 19 is fluidically connected to the cavity 23 of the gas exchange unit 1. In addition, the cavity 23 is connected to the line 22 and thus to the section shown. Figure 7 The vacuum source 16 shown is fluidically connected. In the second position of the closing piston 18, the air accumulated in the cavity 23 can be discharged via the fluid line 19 and the line 20.

[0053] Figure 12 Figure 1 shows a perspective view of a venting device according to a third embodiment. The venting device 15 is fluidically connected to the vacuum source 16 via line 22. The design differs in… Figure 12 shown version of the one in Figure 7 shown version in the design of the adjustment element 21. Figure 13It can be seen that the adjustment element 21 is designed as a rotary knob.

[0054] Figure 14 shows a cross-sectional view of the in Figure 13 shown venting device 15 and the adjusting element 21. As can be seen from Figure 14 As can be seen, in the first position of the closing piston 18, there is no fluidic connection between the line 22 and the cavity 23. Thus, in the first position of the closing piston 18, the air in the cavity 23 cannot be discharged. The closing piston 18 is connected to the adjusting element 21 in a rotationally fixed manner.

[0055] Figure 15 shows an enlarged view of the in Figure 12 shown venting device 15 and the adjusting element 21, wherein the venting device 15 is in the second operating state. To transfer the venting device 15 from the first operating state to the second operating state, the adjusting element 21 is rotated.

[0056] Figure 16 shows a cross-sectional view of the in Figure 15 shown venting device 15 and the adjusting element 21. In the second position of the closing piston 18 there is a fluidic connection between the cavity 23 and the line 22. To transfer the closing piston 18 from the first position to the position shown in Figure 16 In the second position shown, the closing piston 18 is moved linearly. The air accumulated in the cavity 23 can be discharged via a gap between the closing piston 18 and a venting device housing 31 and via the line 22 to the vacuum source 16.

[0057] Figure 17Figure 1 shows a sectional view of the venting device according to a fourth embodiment. The closing piston 18 of the venting device 15 differs from the closing pistons described above in that it has a weakening 25. The weakening 25 corresponds to a cut in the closing piston 18. The weakening 25 is located in a region of the closing piston 18 that extends into the cavity 23. Another difference is that the closing piston 18 has a recess 26. Figure 17 the closing piston 18 is in the first position so that the air accumulated in the cavity 23 cannot be discharged.

[0058] Figure 18 Figure 1 shows a sectional view of the venting device 15 according to the fourth embodiment, wherein the venting device 15 is in the second operating state. As can be seen from Figure 18As can be seen, the adjusting element 21 penetrates through the closing piston 18. In particular, the adjusting element 21 penetrates through the closing piston 18 in the region of the weakened portion 25. As a result of the adjusting element 21 passing through the closing piston 18, one piston portion 33 and another piston portion 34 move away from one another. The adjusting element 21 is partially arranged in the recess 26. The adjusting element 21 has an opening 27 on its portion located in the cavity 23, through which opening air is discharged from the cavity 23.

[0059] Figure 19 shows a sectional view of the venting device 15 according to a fifth embodiment. The venting device 15 has a sealing ring 29, which is attached to the closing piston 18. In addition, the venting device 15 has a return means 30, which is designed such that it returns the closing piston 18 from the Figure 20 shown second position into the Figure 19 shown first position. The return element 30 is supported at one end on the closing piston 18 and at the other end on a venting device housing 31.

[0060] Figure 20 shows a sectional view of the venting device 15 according to the fifth embodiment, in which the venting device 15 is in the second operating state. As can be seen from Figure 20As can be seen, the closing piston 18 is moved linearly by an adjustment element 21 (not shown). In particular, the closing piston 18 is pressed into the cavity 23 to such an extent that a gap exists between the closing piston 18 and the venting device housing, through which space the air accumulated in the cavity 23 is discharged. The air discharged from the cavity flows via line 20 to the vacuum source 16. When the closing piston 18 is moved into the second position, the return element 30 is tensioned.

[0061] Figure 21 shows a sectional view of a venting device 15 according to a sixth embodiment, in which the venting device 15 is in a first operating state in which a flushing of the venting device 15 takes place. In the Figure 21In the first position of the closing piston 18 shown, the fluid line 19 of the closing piston 18 is fluidically connected to a supply line 20. A rinsing agent is supplied via the supply line 20, which, as shown by the arrows, flows through the fluid line 19 and exits the closing piston 18. In the first operating state, there is no fluidic connection between the fluid line 19 and the cavity 23.

[0062] Figure 22 shows a sectional view of a venting device 15 according to a sixth embodiment, in which the venting device 15 is in a second operating state in which the venting process takes place. In the second position of the closing piston 18, a fluidic connection exists between the fluid line 19 and the cavity 23. The air in the cavity 23 can be discharged through the fluid line 19, as shown by the arrows.

[0063] Figure 23shows an embodiment of an outlet housing 11. The outlet housing 11 has an outlet 12. The cross-sectional area of ​​the outlet 12 decreases in the flow direction, as shown in the cross-sectional view of the outlet in Figure 22 The inlet housing 5, the outlet housing 11 and the housing part 3 form a housing of the gas exchange unit 1.

[0064] The outlet 12 has a deflection 13. The deflection angle is 90°, but can also be between 70° and 90°. The continuous decrease in the cross-sectional area of ​​the outlet 12 accelerates the fluid (blood), effectively counteracting the formation of secondary vortices or flow separation.

[0065] The outlet housing 11 optionally features stabilizers 8, which can be designed as webs or crossbars. During confinement, where high temperatures can be reached, the geometry of the outlet housing 11 is thus maintained and essentially remains unchanged by temperature variations.

[0066] Figure 24 shows a cross-sectional view of the outlet 12. The cross-sectional area 10 of the outlet 12 narrows continuously in the direction of flow of the fluid (blood) in the area of ​​the change in the main flow direction (deflection 13). The flow direction is indicated by an arrow. The narrowing can be asymmetrical. The cross-sectional area 10 can be variable along the length of the outlet 12. The fluid (blood) is accelerated by a continuous decrease in cross-sectional area on the outlet side of the gas exchange unit 1.

[0067] It should be noted that the methods, devices, and systems described in this document can be used both alone and in combination with other methods, devices, and systems described in this document. Furthermore, any aspects of the methods, devices, and systems described in this document can be combined in a variety of ways. In particular, the features of the claims can be combined in a variety of ways.

[0068] The invention is described in detail with reference to the drawings and the above description. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to one skilled in the art. The terminology used in the detailed description of the embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like characters refer to like elements.

Claims

1. Gas exchange unit (1), in particular an oxygenator, for enriching blood with oxygen and for removing carbon dioxide from the blood, comprising hollow fiber mats (32), comprising a housing with an inlet housing (5), comprising an inlet (7) for the blood, wherein the inlet (7) is arranged acentrically on the inlet housing (5) and is inclined towards the inlet housing (5) in such a way that the blood can be provided with a rotation, characterized in that suitable structures (6, 6a, 6b) are arranged on the inner blood-conducting surface of the inlet housing (5) in such a way that the flow of the blood flowing through can additionally be distributed as homogeneously as possible.

2. Gas exchange unit (1) according to Claim 1, wherein the inlet (7) is arranged on the front side of the housing of the gas exchange unit (1), wherein the inlet housing (5) forms the front side of the housing of the gas exchange unit (1).

3. Gas exchange unit (1) according to Claim 1 or 2, wherein the inlet (7) is connected to an inlet housing (5) whose surface has structures (6, 6a, 6b), wherein in particular the structures (6, 6a, 6b) are arranged in a shovel-like or web-like manner or as cross-members on the surface of the inlet housing (5).

4. Gas exchange unit (1) according to one of the preceding claims, wherein the inlet (7) has a cross-sectional area which widens continuously and / or asymmetrically in the flow direction and / or which is variable over the length of the inlet (7).

5. Gas exchange unit (1) according to one of the preceding claims, wherein a diameter expansion (dD) of the inlet (7) over the running length (dL) of the inlet (7) is less than 45°.

6. Gas exchange unit (1) according to one of the preceding claims, wherein the gas exchange unit (1) has an outlet (12) whose cross-sectional area continuously decreases in the flow direction and / or which comprises a deflection.

7. Gas exchange unit (1) according to one of the preceding claims comprising a venting device (15), wherein a. the venting device (15) can be switched optionally into a first operating state in which flushing of the venting device (15) is possible, or into a second operating state in which venting of a cavity (23) of the gas exchange unit (1) is possible, or b. the venting device (15) can be switched optionally into a first operating state in which no venting of a cavity (23) of the gas exchange unit (1) is possible, or into a second operating state in which venting of the cavity (23) of the gas exchange unit (1) is possible.

8. Gas exchange unit (1) according to Claim 7, wherein the venting device (15) comprises a flexible membrane (17).

9. Gas exchange unit (1) according to one of Claims 7 or 8, characterized by an adjusting element (21) for switching the venting device (15) into the first operating state or into the second operating state, wherein in particular the venting device (15) has a closing piston (18) which can be switched into a first position to realize the first operating state or into a second position to realize the second operating state and / or the closing piston (18) for switching from the first position to the second position or vice versa a. is mounted linearly movable and / or b. is rotatably mounted and / or c. is designed such that one piston section (33, 34) is movable relative to another piston section (33, 34).

10. Gas exchange unit (1) according to Claim 9, characterized in that the closing piston (18) has a fluid line which a. in the first position is not fluidically connected to the cavity (23) and in a second position is fluidically connected to the cavity (23) and / or which b. in the first position is fluidically connected to a supply line for supplying a rinsing agent and in the second position is not fluidically connected to the supply line.

11. Gas exchange unit (1) according to Claim 9 or 10, characterized in that a. a sealing ring is attached to the closing piston (18) and / or that b. a return element (30) is operatively connected to the closing piston (18) in such a way that the return element (30) presses the closing piston (18) from the second position into the first position.

12. Gas exchange unit (1) according to one of Claims 9 to 11, characterized in that the closing piston (18) has a weakening which is designed such that a. in the second position of the closing piston (18) the adjusting element (21) passes through the closing piston (18) and / or that b. in the first position of the closing piston (18) no venting is possible.

13. Gas exchange unit (1) according to one of Claims 1 to 12, wherein the hollow fiber mats (32) are embedded in the gas exchange unit (1) and a transition from the embedded hollow fiber mats (32) to adjacent components has oblique transitions (9).

14. Gas exchange unit (1) according to one of the preceding Claims 3 to 13, characterized in that the inlet housing (5) has stabilizers (8).

15. Method for producing a gas exchange unit (1) according to one of Claims 1 to 14, comprising inserting the casting compound for embedding the fiber ends, whereby the insertion is carried out once, forming a cylindrical cavity (23) in the central region of the gas exchange unit (1).