Gas exchange device

Abstract

A gas exchange device (100) for transferring a gas component between a gas and a flow of blood is presented, comprising a first gas exchange layer (111) and a second gas exchange layer (122), each comprising a plurality of hollow fibres, and a mixer layer (120) arranged between the first and second gas exchange layer. The gas exchange device (100) is configured to allow the flow of blood to pass through the first gas exchange layer, the mixer layer, and the second gas exchange layer, wherein each of the plurality of hollow fibres comprises a gas permeable wall configured to transfer the gas component within the fibre and the blood outside the fibre. The mixer layer comprises a plurality of plates configured to redirect at least a portion of the blood, passing over the plurality of plates, to enhance mixing of the flow of blood. To be published with

Description

[0001] GAS EXCHANGE DEVICE

[0002] Technical Field

[0003] The present disclosure relates to a gas exchange device for transferring a gas component between a gas and a flow of blood.

[0004] Background

[0005] Gas exchange in blood is a physical process by which gases move through a membrane, such as the blood-air barrier in the alveoli of a mammal lung, to allow oxygen to be taken up by the blood and carbon dioxide to be released from the blood.

[0006] In cases of respiratory failure or bypass, an external gas exchange device may be used to support or replace the function of a patient’s lungs. Such external gas exchange devices, also known as membrane oxygenators, typically use a sweep gas to enrich the patient’s blood with oxygen and to remove carbon dioxide. Following the principle of the lung, a membrane forms a barrier between the patient's blood and the sweep gas containing the gases necessary for blood oxygenation. For this reason, membrane oxygenators may be equipped with hollow fibres acting as the oxygenation membrane. Thus, the hollow fibres separate the blood and gas compartment and is responsible for the exchange of oxygen and carbon dioxide in the blood.

[0007] Summary

[0008] An object of the present disclosure is to provide a new type of gas exchange device which is improved over prior art and which eliminates or at least mitigates problems associated with buildup of gas-saturated boundary layer in the blood in close proximity to the hollow fibres. More specifically, an object is to provide a gas exchange device that is configured to manipulate a flow of blood to reduce the buildup of gas-saturated boundary layers. These objects are addressed by the technique set forth in the appended independent claims with preferred embodiments defined in the dependent claims related thereto.

[0009] According to a first aspect, there is provided a gas exchange device for transferring a gas component between a gas and a flow of blood. The gas exchange device comprising a first gas exchange layer and a second gas exchange layer, each comprising a plurality of hollow fibres, and a mixer layer arranged between the first and the second gas exchange layer. The gas exchange device is configured to allow the flow of blood to pass through the first gas exchange layer, the mixer layer, and the second gas exchange layer during use. Each of the plurality of hollow fibres comprises a gas permeable wall configured to transfer the gas component between the gas within the fibre and the blood outside the fibre. Further, the mixer layer comprises a plurality of plates configured to redirect at least a portion of the blood, passing over the plurality of plates, to enhance mixing of the flow of blood.

[0010] In some examples, one or more of the plurality of plates is curved to redirect at least a portion of the blood as it passes over said plate. In different words, the plate may be shaped to alter a direction of the flow of blood during use. One advantage of this may be that radial components may be provided to the flow of blood increasing gas exchange and efficiency of the gas exchange device due to a decreased risk of buildup of a saturation layer.

[0011] In some examples, one or more of the plurality of plates is twisted to impart a rotation to at least a portion of the flow of blood during use. One benefit of this may be that the twisting may introduce radial components and an angular velocity about the flow axis to the flow of blood increasing gas exchange and efficiency of the gas exchange device due to a decreased risk of buildup of a saturation layer.

[0012] In some examples, for one or more of the plurality of plates, an upstream edge is arranged at an angle to a downstream edge, the angle being between 30° and 150°, such as between 45° and 135°, such as about 90°.

[0013] In some examples, one or more of the plurality of plates is arranged to split at least a portion of the flow of blood into a first partial flow and a second partial flow. This may be beneficial in that the flow of blood is further mixed increasing gas exchange and efficiency of the gas exchange device due to a decreased risk of buildup of a saturation layer.

[0014] In some examples, one or more of the plurality of plates is arranged to guide at least some of the first partial flow between a first pair of the hollow fibres and at least some of the second partial flow between a second pair of the hollow fibres during use. One positive effect of this may be that the flow of blood is further mixed increasing gas exchange and efficiency of the gas exchange device due to a decreased risk of buildup of a saturation layer.

[0015] In some examples, the hollow fibres of the first and / or second gas exchange layer and the plates of the mixer layer are planarly arranged. This may be advantageous in that there may be comparably less resistance for the flow of blood to pass through the gas exchange device.

[0016] As mentioned above, the gas exchange device may comprise at least two gas exchange layers, wherein the mixer layer is arranged between said gas exchange layers. One advantage of this may be increased gas exchange and efficiency of the gas exchange device due to a decreased risk of buildup of a saturation layer. It will however be appreciated that the gas exchange device in some examples may comprise a single gas exchange layer. In such a configuration, the mixer layer may be arranged upstream of the gas exchange layer, relative a flow direction of the flow of blood, so as to enhance mixing of the blood.

[0017] In some examples, the plurality of hollow fibres extend in parallel. This may be beneficial as it may provide a simplified process of feeding the gas through the hollow fibres.

[0018] In some examples, the plurality of hollow fibres of each of the first and second gas exchange layers comprises a first set of hollow fibres extending in a first direction and a second set of fibres extending in a second direction, orthogonal to the first direction. One benefit of this may be increased gas exchange and efficiency of the gas exchange device due to a decreased risk of buildup of a saturation layer.

[0019] In some examples, the gas permeable wall of the hollow fibres is formed from a polymer.

[0020] In some examples, two or more of the plurality of plates are arranged one after the other in the flow direction of the flow of blood during use. One advantage of this may be that the flow of blood is further mixed increasing gas exchange and efficiency of the gas exchange device due to a decreased risk of buildup of a saturation layer.

[0021] According to a second aspect of the present disclosure, there is provided an oxygenator comprising a gas exchange device according to the first aspect and a housing accommodating the gas exchange device. The housing comprises a blood inlet and a blood outlet configured to allow a flow of blood to pass through the gas exchange device and a gas inlet and a gas outlet configured to allow a gas to pass through the plurality of hollow fibres of the first and second gas exchange layer.

[0022] Further features and advantages of the disclosure will become apparent from the following description of preferred embodiments of the disclosure, given by way of example only, which is made with reference to the accompanying drawings.

[0023] Brief Description of the Drawings

[0024] Embodiments of the invention will be described in the following; references being made to the appended diagrammatical drawings which illustrate non-limiting examples of how the inventive concept can be reduced into practice.

[0025] Fig. 1 shows a perspective view of a gas exchange device according to examples of the present disclosure;

[0026] Figs. 2A-B show schematic views of a gas exchange devices according to examples of the present disclosure;

[0027] Fig. 3 shows a perspective view of a mixer layer according to examples of the present disclosure;

[0028] Fig. 4 shows a perspective view of a plate of a mixer layer according to examples of the present disclosure;

[0029] Fig. 5 shows a perspective view of an arrangements of plates of a mixer layer according to examples of the present disclosure;

[0030] Fig. 6 shows a schematic view of a gas exchange devices according to examples of the present disclosure; and

[0031] Fig. 7 shows schematic views of an oxygenator according to examples of the present disclosure.

[0032] Detailed Description

[0033] Gas exchange devices as will be described herein may be utilized in e.g., cardiopulmonary bypass machines (heart-lung machine) providing circulatory and respiratory support in the operating theatre while the heart is stopped for surgery, extracorporeal membrane oxygenator (ECMO) devices providing circulatory and respiratory support in intensive care units, and extracorporeal carbon dioxide removal (ECCO2R) devices removing excess carbon dioxide from the blood. Although the system, devices and examples provided herein are mainly with reference to transferring a gas component between a sweep gas flow and blood in a circulatory system of a patient, it is noted that the teachings presented may be applied more generally to for transferring a gas component between a sweep gas flow and a biological liquid flow. Examples of applications for the medical device and systems comprising the medical device include, but are not limited to, oxygenation of blood, removal of carbon dioxide from blood, continuous renal replacement therapy (CRRT), removal of carbon monoxide from blood, removal of nitrogen from blood (e.g. diving sickness therapy), or adding nitric oxide to blood, or a combination of two or more thereof.

[0034] Generally, in current membrane oxygenators, one factor limiting gas diffusion is blood-side resistance. In theory, blood side resistance to mass transfer may be significantly higher than the gas and membrane phase resistances. This is due to the formation of a laminar boundary layer on the blood side causing a reduction of the mass transfer coefficient. To this end, one drawback with current hollow fibre membranes is the build-up of a gas-saturated boundary layer in the blood in close proximity to the hollow fibres. This boundary layer acts as a diffusion barrier to the gas transfer and causes a limitation in gas exchange since the transport of gas through the membrane is faster than the transport of gas in the blood.

[0035] This is illustrated in Fig. 1, wherein a conceptual gas exchange device 100 is shown. The gas exchange device 100 comprises a plurality of gas exchange layers 111, 112, 113, 114, 115 stacked along flow path of blood 10, indicated by a flow axis X. Each gas exchange layer 111, 112, 113, 114, 115 comprises a plurality of hollow fibres 112a, 112b, 112c, 112d, 112e, only indicated in one gas exchange layer 112 in Fig. 1 for eligibility. The hollow fibres 112a, 112b, 112c, 112d, 112e are configured to allow a gas to pass from a first end of a hollow fibre 112a, 112b, 112c, 112d, 112e to an opposite second end of the hollow fibre 112a, 112b, 112c, 112d, 112e. The hollow fibres 112a, 112b, 112c, 112d, 112e of an associated gas exchange layer 111, 112, 113, 114, 115 are spaced apart to allow the flow of blood 10 to pass between two adjacent hollow fibres 112a, 112b, 112c, 112d, 112e. As a laminar flow of blood 10 streams through the gas exchange device 100 along the flow axis X, gas components such as, for example, oxygen, carbon dioxide, or anaesthetic agents, may be exchanged between the gas flowing though the hollow fibres 112a, 112b, 112c, 112d, 112e and the blood flowing between the hollow fibres 112a, 112b, 112c, 112d, 112e. However, transport of gas through outer surfaces of the hollow fibres 112a, 112b, 112c, 112d, 112e is comparably faster than transport of gas in the blood causing buildup of the boundary layer 10’ as indicated in the magnified portion of Fig. 1. As a consequence, mixing gas- saturated blood from the boundary layer 10’ with unsaturated blood from a bulk flow of blood may increase the overall transport of gas and decrease efficiency of the gas exchange device 100.

[0036] The hollow fibres 112a, 112b, 112c, 112d, 112e may be fibres of any suitable shape, material or form. In some examples, the hollow fibres 112a, 112b, 112c, 112d, 112e are porous hollow fibres of a suitable polymer material.

[0037] The present disclosure addresses the problem of decreased efficiency by, to a degree, manipulating the laminar flow of blood 10 through the gas exchange device 100. To this end, a mixer layer 120 is introduced upstream of one or more of the gas exchange layers 111, 112, 113, 114, 115. The mixer layer 120 may be described as a structure configured to reduce the boundary layer 10’ by causing convective mixing of saturated blood from the boundary layer 10’ with unsaturated blood from the flow of blood 10. In Figs. 2A-B, schematical side views of gas exchange devices 100 comprising a mixer layer 120 upstream of a gas exchange layer 111, 112 is shown.

[0038] As used herein, laminar flow may be interpreted in its broadest sense. Laminar flow typically refers to the smooth and orderly movement of blood, where the blood travels along well-defined, straight or gently curving paths such as those provided by the hollow fibres 112a, 112b, 112c, 112d, 112e. In a predominantly laminar blood flow, which is not manipulated or otherwise influenced by any mixer layer 120, the blood moves through the gas exchange device 100 without significant mixing between adjacent layers. Generally, the hollow fibres 112a, 112b, 112c, 112d, 112e are arranged sufficiently close together to substantially prevent occurrence of turbulent flows. In this type of flow, the fluid may be described as moving in substantially parallel streams or layers, sliding past each other like sheets, and each layer maintains its own trajectory without significantly interfering or mixing with the others, except for the negligible mixing provided by the hollow fibres 112a, 112b, 112c, 112d, 112e themselves, i.e., diffusion between the gas exchange layers 111, 112, 113, 114, 115. The flow may be described as is steady and predictable, characterized by a substantially consistent velocity at any given point within the fluid.

[0039] In the context of a laminar, or substantially laminar, flow where a liquid like blood moves smoothly along the central axis of a device, such as the flow axis X, this may be described as a substantially longitudinal or axial flow. As used herein, upstream and downstream is in reference to a direction of the flow of blood 10, or an intended direction of the flow of blood 10, along the flow axis X. A flow along the flow axis X will be describes as an axial flow. The mixer layer 120 may be an additional layer of the gas exchange device 100, or a replacement to one or more of the gas exchange layers

[0040] 111, 112, 113, 114, 115. The gas exchange device 100 may comprise more than one gas exchange layer 120.

[0041] As used herein, the term manipulate, and the phrase to manipulate a flow such as a laminar flow, may be understood as to adjust or modify flow characteristics of the flow in a controlled and deliberate manner, preferably without inducing turbulence. This manipulation may comprise influencing the behaviour of the smoothly moving fluid so that its orderly layers continue to glide past one another without chaotic disturbances, but with increased mixture. Manipulating the flow may entail altering parameters such as velocity, direction, or pressure gradients to achieve a desired effect while preserving the streamlined nature of the movement. Additionally, or alternatively, manipulating may be described as steering or guiding the laminar flow through subtle interventions that maintain stability and uniformity of the blood. This may comprise shaping a pathway the fluid follows, adjusting boundary conditions, and / or introducing gentle forces that affect how the fluid progresses. In other words, manipulating a laminar flow comprises handling and / or controlling motion of the fluid to achieve specific outcomes, such as enhancing mixing, directing the flow to particular regions, and / or modifying flow profiles.

[0042] In Fig. 2A, a mixer layer 120 is arranged before the gas exchange layers 111,

[0043] 112, 113, 114, 115 of the gas exchange device 100. In Fig. 2B, the mixer layer 120 is arranged between the gas exchange layers 111, 112, 113, 114, 115 of the gas exchange device 100.

[0044] As mentioned above, the mixer layer 120 is configured to disrupt, change, manipulate or otherwise alter an axial flow though the gas exchange device 100. An example of such a mixer layer is shown in Fig., 3, wherein the mixer layer 120 comprises a plurality of components 121, 122, 123 arranged and configured to introduce a lateral flow component to a substantially axial flow of blood 10. In Fig. 3, this is indicated by flow vectors of the flow of blood 10 being substantially parallel to the flow axis X upstream from the mixer layer 120, and having a component in a radial direction to the flow axis X, i.e., being angled to the flow axis X downstream from the mixer layer 120. That is to say, as the flow of blood 10 enters the mixer layer 120, the flow is substantially parallel to the flow axis X, and as the flow of blood 10 exits the mixer layer 120, the flow of blood 10 is manipulated. The flow of blood 10 may, as indicated in Fig. 3, be angled with respect to the flow axis, i.e., no longer substantially parallel to the flow axis X.

[0045] The manipulation of the flow of blood 10 by the mixer layer 120 to introduce a radial component in the flow of blood may be described as adding motion that extends outward or inward from this flow axis X. This adjustment causes the blood to not only progress forward along the length of the flow axis X, but also to spread perpendicularly, incorporating a transverse or lateral movement with respect to the flow axis X. That is to say, integrating a radial aspect, the fluid particles, e.g., blood cells, will cause fluid particles to traverse in one or more directions orthogonal to the main flow path along the flow axis X. This means that each particle has velocity components both along the flow axis X (axial velocity) and across the flow axis X (radial velocity). This may be described as a multidirectional flow pattern. The blood flow 10 will transform from being substantially unidirectional to exhibiting motion in multiple dimensions. This change may be described as the blood flow exhibiting helical or spiral flow patterns, where, e.g., the blood follows a corkscrew-like trajectory. The addition of a radial motion component may cause centrifugal effects to be induced. Centrifugal effects may cause the fluid elements to move in a swirling or vortical manner around the axis while continuing to advance longitudinally along the flow axis X. Modifying an axial laminar flow to include a radial component may be described as augmenting the flow along the flow axis X to further comprise a perpendicular motion relative to the primary direction, i.e., the flow axis X. The modified flow may be described as a combined flow that comprises both forward movement along the flow axis X and outward and / or inward movement across the radius flow axis X. The mixer layer 120 provides is a more complex flow dynamics, that is to say, the mixer layer increases mixing and interaction within the blood due to added dimensionality of motion.

[0046] The addition of radial movement by the mixer layer 120 will be further explained, but may be provided by any suitable component 121, 122, 123, device or configuration that alter a flow pattern of the blood. In some examples, the mixer layer 120 may be configured with spiral or helical structures arranged to induce a swirling motion, causing the blood to experience centrifugal forces that push it radially outward. Similarly, the mixer layer 120 may comprise one or more channels with gradual expansions and / or contractions configured to provide pressure differentials of the blood encouraging the fluid to move toward or away from a centreline of the flow. In some examples, the mixer layer 120 may comprise obstacles and / or vanes arranged and oriented at specific angles to deflect portions of the flow, causing these portions to diverge from the axial path. These structures may be strategically arranged to provide a controlled radial flow component without causing turbulence.

[0047] The addition of a radial component to the flow of blood 10 may increase a flow at an outer surface of the hollow fibres 112a, 112b, 112c, 112d, 112e, thereby reducing buildup of gas-saturated fluid at the outer surface. That is to say, buildup of a boundary layer 10’ may reduce and the efficiency in gas exchange of the gas exchange device 100 may increase.

[0048] In the following, specific examples of mixer layers 120 will be presented. The examples provided should not be considered an exhaustive list of mixer layers 120 but rather a collection of examples to show suitable implementation examples. The examples provided may be freely combined with each other such that one mixer specific layer 120 comprises components 121, 122, 123 from different examples. Additionally, or alternatively, one gas exchange device 100 may very well comprise more than one mixer layer 120, and the different mixer layers 120 may be mixer layers 120 according to any one example and are not required to be according to the same example. Some mixer layers 120 will be described as comprising components 121, 122, 123 in the form of plates 121, 122, 123, but other shapes such as channels, funnels, pipes, etc. are well within the scope of the present disclosure.

[0049] Furthermore, it should be noted that a component 121, 122, 123 that is plateshaped may be understood as an element exhibiting a substantially flat, planar form where two of its dimensions, e.g., length and width, are significantly larger than its thickness. This means a plate-shaped component 121, 122, 123, or a plate for short, may exhibit an extensive surface area compared to its thickness, giving it a comparably thin, sheet-like appearance. Such a component may be described as laminar, slab-like, wafer-thin, or as embodying a flat geometry. A plate may be described as characterized by having a comparably broad, expansive surfaces and minimal profile, and may be referred to as a panel, sheet, or disc. A geometry of a plate may be described as exhibiting significantly larger dimensions in two directions than in a third direction in a cartesian coordinate system.

[0050] In further reference to Fig. 3, the manipulation of the flow of blood 10 may be provided by curved and / or angled plates. The plates 121, 122, 123 may be angled with respect to the flow axis X to impart a radial component to the flow of blood 10. That is to say, along the flow axis X, a first end of a plate 121, 122, 123 is arranged radially offset from an opposite second end of the plate 121, 122, 123. In order to provide a smoother manipulation of the blood, and reduce a risk of turbulence, the radial offset may be provided by introducing a curvature on the plates 121, 122, 123 along the flow axis X, i.e., the plates 121, 122, 123 may be curved or bent with respect to the flow axis X.

[0051] In Fig. 4, one component 121, in the form if a plate 121, of a mixer layer 120 according to some examples is shown. In this example, the plate 121 is twisted about the flow axis X. The twisted shape of the plate 121 is provided to impart a rotation the flow of blood 10 at the twisted plate 121. The rotation of the flow of blood 10 may be described as the blood having an angular velocity about the flow axis X or the blood having a circumferential component to the flow axis X. This is illustrated in Fig. 4 by a first end 121u (sometimes referred to as an upstream end 121u) of the plate 121 being arranged at a different angle about the flow axis X compared to a second end 121d (sometimes referred to as a downstream end 12 Id) of the plate 121. A plate 121 that exhibits a twisted shape may be described as a plate 121 where an originally flat and planar form has been deformed such that different sections rotate about the flow axis X, relative to each other. This deformation may impart a helical or spiral geometry to the plate 121. In this twisted configuration, surfaces of the plate 121 may be described as no longer being aligned in the same plane. A twisted plate 121 may be described as points along the plate 121 being displaced angularly, creating a continuous twist along a length or width (depending on definition) of the plate 121. Edges of the twisted plate 121 may be described as rising and falling in a wave-like pattern, and the overall shape of the twisted plate 121 becomes non-planar. The twisted shape may be described as following a spiralling path around / about the flow axis X. The twisted plate 121 may be described using terms such as helically deformed, torsionally warped, or spirally contorted. The twisted plate 121 may be described as exhibiting a shape that combines both rotational and translational displacements of its parts. A plate 121 exhibiting a twisted shape may be described as a plate 121 that has been altered from a flat, even state into a configuration where it exhibits a continuous angular deformation around an axis, leading to a helical or spiral form. This geometry may be characterized by its warped and twisted appearance.

[0052] In the example shown in Fig. 4, the upstream edge 121u is arranged with an angle of about 180° to the downstream edge 121d to the flow axis X. This is one example, and the amount of rotation between the upstream edge 121u and the downstream edge 12 Id may be configured based on e.g., a flow rate of the blood, an axial extension of the plate 121 etc. In some examples, the rotation between the upstream edge 121u and the downstream edge 12 Id is more than 360°. To reduce a risk of turbulence, to limit an axial extension of the plate 121 (and thereby the mixer layer 120) and not to significantly limit the axial flow of the blood, the upstream edge is arranged between 30° and 150° to the downstream edge 121 d, preferably 45° and 135° to the downstream edge, such as 90°. In Fig. 4, and any other example, one or more of the edges 121 d, 121u, both along the flow axis X and radial to the flow axis X, and / or corners of the plate 121 may be rounded or bevelled to further decrease a risk of introducing turbulence in the flow of blood 10.

[0053] Each mixer layer may be composed of more than one plate in series along the flow axis X. This is illustrated in Fig. 5 where a first plate 121 is arranged upstream from a second plate 122. In Fig. 5, the first and second plates 121, 122 shown as twisted plates, but also curved plates (see Fig. 2), angled plates or combinations of curved, angled and / or twisted plates may be arranged in series along the flow axis X. The plates 121, 122 may be arranged in series along the flow axis X to further manipulate the flow of blood 10. Additionally, or alternatively, the plates 121, 122 may be arranged in series as shown in Fig. 5 to increase a mixture of the blood. To accomplish this, a downstream edge 121 d of the first plate 121 is rotated about the flow axis X compared to an upstream edge 122u of the second plate 122. In other words, the edges 121 d, 122u of the plates 121, 122 facing each other are mutually rotated. As a result, as seen in Fig. 5, the flow of blood 10 is, when it passes the upstream edge 121u f the first plate 121, split into a first partial flow 10a and a second partial flow 10b. As the first and second partial flows 10a, 10b pass the upstream edge 121u of the second plate 122, they are split once more into further partial flows lOaa, lObb causing the blood to mix.

[0054] The split of the blood into partial flows 10a, 10b as illustrated in Fig. 5 is not necessarily linked to the arrangement of the plates in series. In Fig. 6, an exemplary gas exchange device 100 is shown. The gas exchange device 100 in Fig. 6 comprises three mixer layers 120a, 120b, 120c although this is for illustrative purposes and in other examples the gas exchange device may comprise only one mixer layer 120, two mixer layers 120 or more than three mixer layers 120. In Fig. 6, each mixer layer 120a, 120b, 120c is sandwiched between two gas exchange layers 111, 112, 113, 114. Also this is an exemplary implementation, and gas exchange layers 120 may be provided anywhere upstream from a gas exchange layer 111, 112, 113, 114, such as upstream from a first gas exchange layer 111. In some examples, two or more mixer layers 120 are placed serially adjacent to each other, as illustrated in Fig. 5.

[0055] In some examples, the arrangement of the plates 121, 122 of a mixer layer 120a, 120b, 120c in relation to a downstream gas exchange layer 111, 112, 113, 114, 115 may be such that the first partial flow 10a is guided between a first pair of the hollow fibres of the downstream gas exchange layer 111, 112, 113, 114, 115, and the second partial flow 10b is guided between a second pair of the hollow fibres of the downstream gas exchange layer 111, 112, 113, 114, 115.

[0056] In some examples, the mixer plates 121 of a first mixer layer are arranged with their downstream edges rotated about the flow axis X compared to an upstream edge 122u of a second mixer layer 121. That is, correspondingly to the arrangement of the plates in Fig. 5, but with one or more gas exchange layers 111, 112, 113, 114, 115 arranged between them.

[0057] In Fig. 1, and the following description, the gas exchanged device 100 has been described as a layered device. It should be noted that although illustrated as such in e.g., Fig, 6, the layers are not necessarily planar but may very well be cylindrical layers coaxially arranged along the flow axis X. Additionally, or alternatively, the mixer layer 120 may be configured to, at least partly, maintain, support, retain or otherwise secure an arrangement of the hollow fibres 112a, 112b, 112c, 112d, 112e.

[0058] Although the arrangement of the respective hollow fibres 112a, 112b, 112c, 112d, 112e are depicted in Fig. 1 as extending substantially parallel to each other within each gas exchange layer 111, 112, 113, 114, this is but one example and the hollow fibres 112a, 112b, 112c, 112d, 112e may very well extend in randomly or at specific angles to each other. In some examples, the hollow fibres 112a, 112b, 112c, 112d, 112e of a specific gas exchange layer 111, 112, 113, 114 may comprise a first set of fibres extending in a first direction and a second set of fibres extending in a second direction. In some examples the second direction is orthogonal to the first direction. Furthermore, the arrangement of the hollow fibres 112a, 112b, 112c, 112d, 112e illustrated in Fig. 1 where the orientation of the hollow fibres 112a, 112b, 112c, 112d, 112e is rotated 90° with respect to an upstream layer and a downstream layer is one example. In other examples, the orientation of the hollow fibres 112a, 112b, 112c, 112d, 112e of a specific gas exchange layer 111, 112, 113, 114 may be rotated less than 90° with respect to an upstream and / or downstream gas exchange layer 111, 112, 113, 114. In further examples, the orientation of the hollow fibres 112a, 112b, 112c, 112d, 112e of a specific gas exchange layer 111, 112, 113, 114 may be rotated more than 90° with respect to an upstream and / or downstream gas exchange layer 111, 112, 113, 114. A mutual rotation between a first gas exchange layer 111 and a second gas exchange layer 112 is not necessarily the same as a mutual rotation between the second gas exchange layer 112 and a third gas exchange layer 113. In some examples, exemplified in e.g. Fig. 6, all hollow fibres 112a, 112b, 112c, 112d, 112e of all gas exchange layer 111, 112, 113, 114 are oriented the same.

[0059] With reference to Fig. 7, an exemplary 1 will be presented. The oxygenator 1 comprises a gas exchange device 100 according to any example presented herein. The gas exchange device 100 is accommodated by housing 2 of the oxygenator 1. The housing 2 is provided with a blood inlet 3i, a blood outlet 3o, a gas inlet 4i and a gas outlet 4o. An upstream end of the gas exchange device 100 is operatively connected to the blood inlet 3i, and a downstream end of the gas exchange device 100 is operatively connected to the blood outlet 3o. Correspondingly, first ends of the hollow fibres of the gas exchange device 100 are operatively connected to the gas inlet 4i, and opposite second ends of the respective hollow fibres of the gas exchange device 100 are operatively connected to the gas outlet 4o.

[0060] The oxygenator 1 may operate by feeding blood having a comparably low concentration of oxygen and high concentration of carbon dioxide into the blood inlet 3i. A gas 20 having a comparably high concentration of oxygen and low concentration of carbon dioxide is feed into the gas inlet 4i. At the gas exchange device 100 of the oxygenator, gas exchange between the blood and the gas 10 occurs such that, blood having a comparably high concentration of oxygen and low concentration of carbon dioxide is provided at the blood outlet 3o and a gas 20 having a comparably low concentration of oxygen and high concentration of carbon dioxide is provided at the gas outlet 4o. The phrases comparably high, and comparably low are to mean relatively higher or relatively lower in comparison to the opposite side of the respective flows. Correspondingly, the oxygenator 1 may be configured for use with anaesthetic gases, such as NO2.

[0061] Although not shown in Fig. 7, the oxygenator 1 may, in some examples, further comprise one or more heat exchangers configured to control a temperature of the blood by warming or cooling it to maintain a specific temperature during oxygenation. The oxygenator 1 may, in some examples, comprise a blood reservoir, serving as a chamber to collect and store blood, aiding in the management of blood volume throughout oxygenation. In some examples, the oxygenator 1 may comprise an air removal system or bubble trap arranged and configured to reduce presence of air bubbles in the blood downstream from the gas exchange device 100. Additionally, or alternatively, in some examples, the oxygenator 1 may comprise on or more filters configured to reduce e.g., microemboli, clots, or other particulates, to enhancing purity of the blood returning to the patient.

[0062] The above embodiments are to be understood as illustrative examples of the invention. Further embodiments of the invention are envisaged, such as heat exchangers, chemical reactors e.g., wherein a product or educt is gaseous and needs to be added or removed. It is to be understood that any feature described in relation to any one embodiment may be used alone, or in combination with other features described, and may also be used in combination with one or more features of any other of the embodiments, or any combination of any other of the embodiments. Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the invention, which is defined in the accompanying claims.

Claims

AMENDED CLAIMS received by the International Bureau on 18 March 2026 (18.03.2026)1. A gas exchange device (100) for transferring a gas component between a gas (20) and a flow of blood (10), the gas exchange device comprising: a first gas exchange layer (111) and a second gas exchange layer (112), each comprising a plurality of hollow fibres (112a, 112b, 112c, 112d, 112e); and a mixer layer (120) arranged between the first gas exchange layer and the second gas exchange layer; wherein the gas exchange device is configured to allow the flow of blood to pass through the first gas exchange layer, the mixer layer, and the second gas exchange layer during use; wherein each of the plurality of hollow fibres comprises a gas permeable wall configured to transfer the gas component between the gas within the fibre and the blood outside the fibre; and wherein the mixer layer comprises a plurality of plates (121, 122, 123) configured to redirect at least a portion of the blood, passing over the plurality of plates, to enhance mixing of the flow of blood.

2. The gas exchange device of claim 1, wherein the first gas exchange layer, the second gas exchange layer, and the mixer layer are stacked in respective planar layers along a direction of the flow of blood.

3. The gas exchange device of claim 1 or 2, wherein one or more of the plurality of plates is curved to redirect said portion of the blood.

4. The gas exchange device of any of claims 1 to 3, wherein one or more of the plurality of plates is twisted to impart a rotation to said portion of the blood.

5. The gas exchange device of claim 4, wherein, for one or more of the plurality of plates, an upstream edge (121u, 122u) is arranged at an angle to a downstream edge(121d, 122d), the angle being between 30° and 150°, such as between 45° and 135°, such as about 90°.

6. The gas exchange device of any of claims 1 to 5, wherein one or more of the plurality of plates is arranged to split at least a portion of the flow of blood into a first partial flow (10a) and a second partial flow (10b).

7. The gas exchange device of claim 6, wherein one or more of the plurality of plates is arranged to guide at least some of the first partial flow between a first pair of the hollow fibres and at least some of the second partial flow between a second pair of the hollow fibres during use.

8. The gas exchange device of any one of claims 1 to 7, wherein the plurality of hollow fibres of each of the first and second gas exchange layer extend in parallel.

9. The gas exchange device of any one of claims 1 to 7, wherein the plurality of hollow fibres of each of the first and second gas exchange layers comprises a first set of hollow fibres extending in a first direction and a second set of fibres extending in a second direction, orthogonal to the first direction.

10. The gas exchange device of any one of claims 1 to 9, wherein the gas permeable wall of the hollow fibres is formed from a polymer.

11. The gas exchange device of any one of claims 1 to 10, wherein two or more of the plurality of plates are arranged one after the other in the flow direction of the flow of blood during use.

12. An oxygenator ( 1 ) compri sing : a gas exchange device (100) of any one of claims 1 to 11; and a housing (2) accommodating the gas exchange device (100); wherein the housing (2) comprises:a blood inlet (3i) and a blood outlet (3o) configured to allow a flow of blood (10) to pass through the gas exchange device (1); and a gas inlet (4i) and a gas outlet (4o) configured to allow a gas (20) to pass through the plurality of hollow fibres (112a, 112b, 112c, 112d, 112e) of the first and second gas exchange layer (111, 112).[0001][0002]STATEMENT UNDER ARTICLE 19 (1)[0003]New claim 2 specifies that the first and second gas exchange layers and the mixer layer are arranged as respective planar layers, stacked along the direction of blood flow. This planar architecture further distinguishes the claimed device from the prior-art configurations cited in the international search report. In particular, D1 , D2, and D4 all rely on curved, cylindrical, or spiral geometries, while D3, although disclosing planar structures, does so only in the context of heatexchange tubes rather than mixer plates. None of these documents teaches or suggests the use of mixer plates positioned between planar hollow-fibre layers.[0004]D1 (WO 2016 / 064715) discloses an artificial lung having cylindrically wound fibres with concentric baffles operating in annular flow chambers. These baffles operate in a round, radial geometry fundamentally different from the planar, sheet-based stacking set out in new claim 2. D2 (WO 2016 / 064715) similarly employs spiral-wound fibre bundles and sleeves to produce a tortuous flow path. As in D1 , the geometry is inherently non-planar. D4 (WO 2015 / 128886) employs a spiralwound filter screen, again relying on a non-planar geometry.[0005]D3 (WO 99 / 49913) discloses a planar stack, but only in the context of heat-exchange tubes. D3 does not disclose any structure comparable to the mixer layer of the present invention, nor any element that redirects blood flow in the manner achieved by the claimed mixer plates. Nothing in D3 suggests introducing planar layers of mixer plates between planar hollow-fibre layers or combining its tubebased planar stack with the curved or spiral geometries of D1 , D2, or D4. D3 therefore cannot bridge the structural and functional gap between the planar configuration of new claim 2 and the non-planar configurations of the remaining documents.[0006]Accordingly, the planar configuration introduced in new claim 2 is not disclosed or suggested by the cited documents. It defines subject-matter that is novel and involves an inventive step, distinguishing claim 2 from cylindrical, spiral, and curved architectures in the prior art.

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