Apparatus and method for exchanging gas between a first exchange medium and a second gaseous exchange medium.

Abstract

The present invention relates to a method and apparatus for exchanging gas between two exchange media using an exchange chamber (1) disposed within the housing of an exchange unit, wherein the exchange chamber (1) is divided into two chamber regions by at least one membrane (2), in which the first side of the membrane (2) is in contact with the first exchange medium in the first chamber region, and the second side of the membrane (2) is in contact with the second gaseous exchange medium in the second chamber region, the first chamber region having a connection for the first exchange medium, the first chamber region being incorporated into a first conduit (3) by this connection, and the first exchange medium being passed through the first chamber region using the first conduit. The second chamber region has a connection for a second gaseous exchange medium, and by this connection the second chamber region is incorporated into the second conduit (4), and the second exchange medium can be guided through the second chamber region using the second conduit, and the gas to be exchanged can be transported across the membrane (2) by diffusion, and the apparatus has a pressure generator (9a), and the pressure generator (9a) can be used to generate a pressure difference of at least 10 mmHg of the second exchange medium relative to the ambient atmospheric pressure in the second chamber region, and at least one membrane (2) is permeable to diffusion with respect to the gas to be exchanged, but impermeable to convection.

Description

[Technical Field]

[0001] The present invention relates to an apparatus for exchanging gas between a first exchange medium and a second gaseous exchange medium, comprising an exchange unit having an exchange chamber disposed within the housing of the exchange unit, wherein the exchange chamber is divided by at least one membrane, preferably a plurality of hollow fibrous membranes, into a first chamber region where the first side of at least one membrane can contact the first exchange medium and a second chamber region where the second side of at least one membrane can contact the second gaseous exchange medium, the first chamber region having an inlet connection and an outlet connection for the first exchange medium, the inlet connection and outlet connection incorporating the first chamber region into a first conduit, and the first exchange medium can be guided through the first chamber region using the first conduit, the second chamber region having an inlet connection and an outlet connection for the second gaseous exchange medium, the inlet connection and outlet connection incorporating the second chamber region into a second conduit, and the second exchange medium can be guided through the second chamber region using the second conduit, and the gas to be exchanged present in one of the two exchange mediums can be transferred by diffusion across the membrane to the other exchange medium.

[0002] The present invention also relates to a method of gas exchange between a first exchange medium, excluding blood, and a second gaseous exchange medium, using an exchange unit having an exchange chamber disposed within a housing of the exchange unit, the exchange chamber being divided by at least one membrane, preferably a plurality of hollow fiber membranes, into a first chamber region in which a first side of the at least one membrane contacts the first exchange medium and a second chamber region in which a second side of the at least one membrane contacts the second gaseous exchange medium, the first chamber region having an inlet connection and an outlet connection for the first exchange medium, the first chamber region being incorporated into a first pipeline by the inlet connection and the outlet connection, the first exchange medium being guided through the first chamber region using the first pipeline, the second chamber region having an inlet connection and an outlet connection for the second gaseous exchange medium, the second chamber region being incorporated into a second pipeline by the inlet connection and the outlet connection, the second exchange medium being guided through the second chamber region using the second pipeline, and an exchange target gas present in one of the two exchange media being transferred by diffusion across the at least one membrane into the other exchange medium.

[0003] Such a device is also called a membrane contactor and is mainly used to enrich or deplete at least one specific gas in the exchange medium on one side or the other side of the exchange chamber. In that case, as is known and also in the present invention, the first exchange medium can be a liquid or gaseous medium and the second exchange medium can be gaseous.

[0004] In the medical field, such a device is used, for example, as a so-called oxygenator to enrich blood with oxygen and at the same time deplete it of carbon dioxide. The present invention preferably relates precisely to this application, i.e., in particular to a so-called oxygenator as an exchange unit according to the present invention, but is not limited thereto. Preferred embodiments also relate to a device for removing carbon monoxide from blood or a device and method for concentrating gas components in one of the two exchange media, in particular in one of the two gaseous exchange media.

[0005] In the prior art, and in the present invention, the division of a replacement chamber by at least one membrane is preferably achieved by sealing at least one membrane against the housing wall of the replacement chamber at its end region. Preferably, a plurality of membranes are provided, formed as hollow fibrous membranes sealed against the housing wall, particularly at the axial end regions. In particular, the radially outward surfaces of the hollow fibrous membranes are sealed against and against the housing wall at the end regions. In the art of such replacement units, this is also called potting. For potting, or sealing, a potting compound is used.

[0006] When the properties of at least one membrane in the exchange chamber are described below, these properties preferably apply to all membranes used in the exchange chamber of the device. When the device or method is described herein using blood as the liquid first exchange medium and oxygen / air as the gaseous second exchange medium as an example, the same characteristics are deemed to be disclosed in relation to other liquid or gaseous first and gaseous second exchange mediums.

[0007] The aforementioned first conduit includes, for example, a source of the first exchange medium on the inlet side of the first chamber region and a sink on the outlet side. In particular, the first conduit may be equipped with a pump for transporting the first exchange medium through the conduit. The first conduit can be incorporated into a circuit, for example. In applications of blood gas exchange, the patient may be part of the conduit, especially the circuit, during the operation of the device. Thus, the patient can form both the source and the sink.

[0008] The aforementioned second pipeline includes, for example, a source of the second exchange medium (e.g., a gas cylinder, gas supply unit) on the inlet side and a sink (e.g., the atmospheric environment) on the outlet side. In particular, the second pipeline may be equipped with a pump for transporting the second exchange medium through the pipeline. The second pipeline can also be incorporated into the circuit, for example, if the second exchange medium is to be reused after passing through the second chamber region.

[0009] In the present invention, preferably, the first chamber region and the first conduit are adjacent to the first side of at least one membrane, which is, for example, the outside of the membrane in the case of a hollow fibrous membrane, and the second chamber region and the second conduit are adjacent to the second side of at least one membrane, which is, for example, the inside of the membrane in the case of a hollow fibrous membrane.

[0010] Alternatively, and more preferably, the first chamber region and the first conduit are adjacent to the first side of at least one membrane, which in the case of a hollow fibrous membrane is, for example, the inside of the membrane, and the second chamber region and the second conduit are adjacent to the second side of at least one membrane, which in the case of a hollow fibrous membrane is, for example, the outside of the membrane.

[0011] That is, the first exchange medium, preferably liquid, such as blood, can alternatively flow around the outside of the hollow fibrous membrane or through the inside of the hollow fibrous membrane, and the second exchange medium, preferably gaseous, is in contact with the other side of the membrane. In applications of blood gas exchange, the second exchange medium during operation of the apparatus according to the present invention is preferably pure oxygen or an oxygen-containing gas, such as air.

[0012] In conventional technology, it is known that such exchange units are only permitted to operate when there is little pressure difference between the second gaseous exchange medium and the surrounding atmospheric pressure. In particular, this results in at least one membrane, especially the hollow fibers used in oxygenerators, not being dense with respect to the convective passage of the exchange medium, so that the pressure in the two chamber regions is at least substantially equivalent to the normal ambient atmospheric pressure surrounding the device. That is, if there is a pressure difference between the second exchange medium and atmospheric pressure, diffusion occurs not only due to the concentration gradient across the membrane, but in the case of a positive pressure difference, gas bubbles from the gaseous second exchange medium may enter the other medium, such as blood, or in the case of a negative pressure difference, liquid blood components, especially plasma, may enter the second gaseous exchange medium through the membrane by convection in the opposite direction. However, in oxygenerator applications in particular, it is necessary to avoid the movement of gas bubbles.

[0013] Therefore, limits have been established on the transfer rates of gases between exchange media, particularly oxygen and / or carbon dioxide or carbon monoxide in oxygenerators, which so far have only been increased by increasing the surface area of ​​the membrane. However, since the membrane surface itself is also classified as harmful to blood, it cannot be easily expanded without constraints, at least in the application of the device as an oxygenerator.

[0014] Therefore, the object of the present invention is to provide an apparatus and method that can achieve an improvement in the exchange rate per unit area of ​​a membrane compared to the prior art. In other words, it should be possible to increase the movement speed of the gas to be exchanged with a given surface area of ​​the membrane, or to reduce the surface area of ​​the membrane with a given movement speed.

[0015] This problem is solved, according to the present invention, by providing a device that includes a pressure generating device, and using the pressure generating device, a pressure difference of at least 10 mmHg of the second exchange medium relative to the ambient atmospheric pressure can be generated in the second chamber region, particularly via the second pipeline, especially during gas exchange operation.

[0016] According to the present invention, this problem is solved by a method in which a pressure generating device is used to generate a pressure difference of at least 10 mmHg in the second exchange medium relative to the ambient atmospheric pressure, particularly through the second conduit, in the second chamber region, particularly during the gas exchange operation, and at least one membrane is permeable to diffusion with respect to the gas to be exchanged in the case of the generated pressure difference, and impermeable to convection with respect to both exchange mediums in the case of the generated / generated pressure difference.

[0017] This allows for a concentration gradient of the exchange target gas between the two exchange media that exist across the membrane and pass through the membrane by diffusion. Furthermore, it enables the partial pressure of the exchange target gas in the second gaseous medium in the second chamber region to be changed relative to the partial pressure corresponding to the concentration of this gas in the first exchange medium, thus leading to another possibility of acceleration due to the pressure difference.

[0018] To generate a pressure difference, for example, the pressure in the second chamber region can be influenced via the second pipeline, preferably increasing or decreasing it, in particular the pressure in the first chamber region remains unaffected and corresponds to the ambient atmospheric pressure to which the device is exposed at its place of use, and optionally to hydrostatic and / or dynamic pressures that may act due to the flow through the first chamber region. Therefore, during the operation of the device, in particular the differential pressure between the chamber regions preferably corresponds to the differential pressure of the second gaseous exchange medium in the second chamber region relative to the ambient atmospheric pressure, taking into account the contribution of the aforementioned pressures.

[0019] Furthermore, according to the present invention, at least one membrane, in particular each hollow fibrous membrane, is intended to be permeable to diffusion with respect to the gas to be exchanged, given the pressure difference that can be generated, and impermeable to convection with respect to both exchange media (and their constituent parts in particular), given the pressure difference that can be generated.

[0020] In particular, this is understood to mean that, due to the concentration difference on both sides of the membrane, the membrane is permeable to individual molecules of the gas to be exchanged, i.e., diffusively permeable in the general sense, but impermeable to the gas bubbles of the gas to be exchanged or the second gaseous exchange medium. In particular, the membrane is also impermeable to the movement of the first exchange medium as droplets or bubbles, especially to the liquid component of the first exchange medium, and especially to plasma when blood is used as the first exchange medium.

[0021] Thus, the convective-dense design of the membrane increases the pressure difference and additional concentration gradient on both sides of the membrane without the risk of the medium itself being able to pass through in the form of bubbles or droplets, which can lead to the aforementioned potential for enhanced gas exchange.

[0022] For this purpose, the material of at least one membrane may, for example, be impermeable to convection, particularly to gas bubbles and / or droplets, across the film thickness, or at least one membrane may have a layer on at least one side or both sides that is impermeable to convection, particularly to gas bubbles and / or droplets of the exchange medium.

[0023] Therefore, according to the present invention, the membrane or its material is impermeable with respect to convection, particularly with respect to the convection of the gas to be exchanged, but permeable with respect to diffusion, and in particular selectively, its permeability to at least one gas to be exchanged is sometimes higher than its permeability to other gas components of the exchange medium.

[0024] The pressure generating device may be formed, for example, by a pressurized gas source that pushes gas into the second chamber region through a second pipeline, or by a pump that delivers gas into or out of the second chamber region through the second pipeline. The pressure generating device can be formed by any technical means suitable for increasing or decreasing the pressure of the second exchange medium in the second chamber region relative to atmospheric pressure.

[0025] Therefore, according to the present invention, the differential pressure can be positive or negative, and the amount of the difference is at least 10 mmHg. Preferably, the present invention can be intended to be configured so that the device is set to variably adjust or control the differential pressure.

[0026] In a preferred embodiment, the apparatus according to the present invention comprises at least one measuring device for measuring an actual value of at least one process parameter in at least one of the exchange media, and the apparatus comprises at least one control device, particularly in the second conduit, which can be used to change the measured actual value of at least one process parameter toward a predetermined target value of at least one process parameter by changing the pressure of the second exchange media in the second chamber region and / or the volumetric flow rate of the second exchange media as an adjustment amount.

[0027] In particular, in that case, it is contemplated that the device is set so as to be able to effect an adjustment change such that a differential pressure according to the present invention of at least an amount of 10 mmHg is continuously present. Thus, while complying with the condition according to the present invention that a differential pressure exists, it is achieved that the target value is controlled or at least approximated by control.

[0028] The measured process parameter can be, for example, the concentration or partial pressure of the gas to be exchanged in the first and / or second exchange medium, or a value depending thereon, for example, the flow rate of the gas to be exchanged. The process parameter can preferably also be the pressure of the second exchange medium in the second chamber region itself, in particular the absolute pressure of the second exchange medium or the relative pressure with respect to atmospheric pressure in the second chamber region or the second pipeline, or the volume flow rate.

[0029] Preferably, it is contemplated that the device is set to control or approximate a process parameter of the gas to be exchanged, such as concentration, or a value depending thereon, in the first and / or second exchange medium, depending on the pressure and / or volume flow rate of the second exchange medium, to a desired, particularly preset target value.

[0030] Particularly preferably, at least one measuring device for measuring at least one of the measured values representing at least one process parameter is provided after the outlet connection in the flow direction in one of the pipelines of the two chamber regions, in particular where the measured value represents or depends on the concentration of the gas to be exchanged in the exchange medium of the chamber region, and at least one control device is provided in the second pipeline of the second chamber region, and it is contemplated that the value of the pressure difference and / or the value of the volume flow rate of the second exchange medium can be changed depending on the measured value by using the control device. Preferably, this is done while continuously maintaining the condition according to the present invention that the pressure difference is at least an amount of 10 mmHg.

[0031] Thus, according to the present invention, it is controlled to be a value representing or depending on a predetermined target value, preferably a concentration, of a process parameter, and for this purpose, the actual value of the process parameter, in particular the actual value of a measured value representing a concentration, is detected, and the control of the pressure and / or the volume flow rate can be performed such that the predetermined target value is achieved or at least approximated.

[0032] In this case, the present invention contemplates being carried out using a difference amount greater than 10 mmHg (i.e., disregarding the sign) between the pressure in the second chamber region (or the second pipeline) and the ambient atmospheric pressure. That is, the pressure in the exchange chamber on the side of the pressure-controlled exchange medium, in particular the second gaseous exchange medium, can preferably be at least 10 mmHg higher or lower than the ambient atmospheric pressure.

[0033] For this purpose, the present invention contemplates a measuring device for technically detecting the ambient atmospheric pressure present around the device, and for selecting the adjusted or preferably controlled pressure of the second exchange medium in the second chamber region depending on the detected atmospheric pressure, thereby achieving the difference with respect to the atmospheric pressure contemplated by the present invention, in particular the difference between the chamber regions, and ensuring that this is particularly continuously maintained during operation.

[0034] That is, according to the present invention, it can be achieved that it can be carried out using a pressure different from the atmospheric pressure by this differential pressure in the second chamber region of the exchange chamber, in particular a positive pressure or a negative pressure, whereby the transfer rate of at least one exchange target gas can be significantly increased compared to the prior art.

[0035] Particularly preferably, the device is intended to be configured to adjust or control a pressure difference of an amount greater than 10 mmHg, preferably greater than 20 mmHg, preferably greater than 50 mmHg, more preferably greater than 100 mmHg, more preferably greater than 200 mmHg, more preferably greater than 300 mmHg, more preferably greater than 400 mmHg, more preferably greater than 500 mmHg, particularly less than 600 mmHg, especially during operation.

[0036] The maximum value of the unsigned amount of the pressure difference is preferably provided to prevent foam formation in the blood, for example in blood applications.

[0037] To satisfy the requirements for these difference values, the present invention preferably envisions that at least one membrane permeable to the gas to be exchanged has a layer on at least one side thereof, particularly the side in contact with the liquid exchange medium, preferably inside (or alternatively outside) at least one hollow fibrous membrane, that prevents the convection of the exchange medium, or is continuously formed as a membrane that prevents the convection of the exchange medium. Preferably, the layer or membrane is formed to withstand without breaking pressure differences of amounts greater than 10 mmHg, preferably greater than 20 mmHg, preferably greater than 50 mmHg, more preferably greater than 100 mmHg, more preferably greater than 200 mmHg, more preferably greater than 300 mmHg, more preferably greater than 400 mmHg, and more preferably greater than 500 mmHg, but particularly less than 700 mmHg, preferably less than 600 mmHg.

[0038] Preferably, this can be achieved, for example, by having at least one of the aforementioned layers formed from a non-porous, particularly discontinuous porous material, preferably silicone, that allows diffusion of the gas to be exchanged, or by having at least one membrane entirely formed from a non-porous, particularly discontinuous porous material, preferably entirely silicone, that allows diffusion of the gas to be exchanged.

[0039] For the formation of the silicone layer, it is known that at least one film comprises a porous support element, particularly a porous hollow fiber, and has a silicone layer on at least one side thereof, preferably with a minimum thickness of 2 micrometers, more preferably 3 micrometers, and even more preferably 5 micrometers.

[0040] Such layers can be formed, for example, by depositing silicone on the inner or outer surface of the film and / or from there into the porous structure of the film. This layer can be formed from silicone components that are present not only in the pores but also on the surface. Overall, it is intended that a minimum thickness of preferably 2 micrometers, more preferably 3 micrometers, and even more preferably 5 micrometers is achieved with both components.

[0041] Particularly preferable, this layer is formed entirely within the pores from the inner or outer surface without the surface itself being covered with silicone. This results in a particularly stable silicone layer because the pore structure has a stabilizing effect.

[0042] Silicone, as a material, is particularly advantageous here because it has high permeability to oxygen and / or carbon dioxide by diffusion, but does not allow convective passage of the two exchange media, especially when the formation of a non-porous layer is preferred. Alternatively, polyurethane, for example, can be used instead of silicone.

[0043] All embodiments of the present invention relating to silicone as described herein can also be formed using other suitable coating means, such as polyurethane.

[0044] As porous, particularly continuous porous support elements, hollow fibrous membranes can be used, for example, in general atmospheric pressure applications for gas exchange between two media, such as in oxygenerators or dialyzers. For example, this can be a hollow fibrous membrane made of materials such as polysulfone, polypropylene, or polymethylpentene.

[0045] The application of silicone or other suitable materials to porous materials, particularly continuous porous support elements, can be carried out, for example, by dissolving or diluting the appropriate material, preferably silicone, in a solvent, and then impregnating the support element with this solution, after which the solvent evaporates and the material remains in the pores and / or on the inner / outer surfaces, depending particularly on post-treatment. When silicone is used as a coating material, it can preferably be dissolved in, for example, n-heptane. Polyurethane as a coating material can preferably be dissolved in dimethylformamide.

[0046] Therefore, a hollow fiber membrane equipped in this manner, particularly a hollow fiber membrane made from the aforementioned material, can be made suitable for the apparatus according to the present invention by subsequently providing it with an impermeable layer made of an appropriate material, especially silicone.

[0047] A preferred embodiment of the apparatus is intended in which at least one control device for controlling pressure and / or volumetric flow rate and at least one measuring device for measuring at least one process parameter, in particular its actual value, are arranged in a pipeline between different chamber regions, the apparatus being configured to have a liquid exchange medium as a first exchange medium during operation in a first chamber region connected to a measuring device, preferably on the outlet side, and the control device being arranged in a pipeline between a second chamber region, preferably on the outlet side, which is configured to have a gaseous second exchange medium during operation of the apparatus. In this case, the control device is preferably intended to be configured to control the positive pressure in the second chamber region with respect to atmospheric pressure, in particular with respect to the first chamber region.

[0048] In such embodiments, the device is preferably configured to operate for enriching oxygen in the blood as a first exchange medium or depleting carbon monoxide, and for that purpose the measuring device is designed to measure, for example, the concentration of oxygen in the blood, in particular the partial pressure of oxygen, or the concentration of carbon monoxide, in particular the partial pressure of carbon monoxide, and is intended to be located in the tubing after the outlet connection of a first chamber region provided for guiding the blood. In this case, preferably this chamber region is intended to be adjacent to the inner surface of a plurality of hollow fibrous membranes.

[0049] Alternatively, at least one control device and at least one measuring device for at least one process parameter may be arranged in the same pipeline, in particular in the pipeline of a second chamber region configured to have a gaseous second exchange medium during the operation of the device, preferably the device is configured to have a liquid exchange medium in the chamber region having a first exchange medium during operation, and more preferably the control device is configured to control a negative pressure in the second chamber region relative to atmospheric pressure.

[0050] Preferably, in this embodiment, the apparatus is configured for the operation of depleting carbon dioxide in the blood as a first exchange medium, and for that purpose, at least one measuring device is designed to measure the concentration of carbon dioxide, in particular the partial pressure of carbon dioxide in the gaseous second exchange medium, and preferably located after the outlet connection of the chamber region provided for guiding the gaseous second exchange medium in the conduit, in particular the chamber region adjacent to the outer surface of the plurality of hollow fibrous membranes.

[0051] When controlling the negative pressure in the second chamber region relative to atmospheric pressure, it is preferable to position at least one control device pressure control element, such as a throttle valve, on the outlet side of the chamber region in the pressure-controlled pipeline. When controlling the positive pressure in the second chamber region relative to atmospheric pressure, it is preferable to position at least one control device pressure control element, such as a throttle valve, on the inlet side of the chamber region in the pressure-controlled pipeline.

[0052] Preferably, the apparatus is further designed so that a predetermined target partial pressure of the gas to be exchanged, or a target value dependent on the partial pressure of the gas to be exchanged, in particular the aforementioned process parameter, can be controlled by controlling the pressure using at least one control device. The target partial pressure is a value representing, and dependent on, the concentration of the gas to be exchanged. The controlled target value may be, for example, the transfer rate of the gas to be exchanged.

[0053] A preferred development of the present invention is that a control device is used to change the volumetric flow rate of the exchange medium in the second pipeline depending on the amount of the pressure difference, depending on the measured values ​​of process parameters, particularly concentration, and that at least one control device is configured to increase the volumetric flow rate, in particular while keeping the pressure difference constant, when the pressure difference exceeds a limit value.

[0054] In this way, if the amount of pressure difference cannot be increased further for reasons such as the rupture of the membrane or membrane layer, the velocity of the gas to be exchanged can also be increased by increasing the volumetric flow rate.

[0055] In general, and therefore particularly in the embodiments described above, a change in volumetric flow rate is performed using at least one control device, retrospectively to a change in pressure for controlling or approximating process parameters, and only when a change in pressure becomes impossible, in particular, for reasons of otherwise exceeding a limit value of the pressure difference.

[0056] Alternatively, generally, an embodiment is possible in which pressure changes are retrospective to volumetric flow rate changes for controlling or approximating process parameters, preferably only when volumetric flow rate changes are no longer possible or would otherwise exceed predetermined limits, using at least one control device.

[0057] Using at least one control device, in all possible embodiments, pressure changes alone, or alternatively volumetric flow rate changes alone, or alternatively both, can be performed in particular sequentially, and in particular in two possible sequences.

[0058] However, the present invention may also be intended to operate in parallel, i.e., simultaneously, a control device for controlling pressure depending on a first process parameter and a control device for controlling volumetric flow rate depending on a second process parameter. For example, in pressure control, the concentration of oxygen in blood or gas can be measured at the outlet as a process parameter, and in volumetric flow rate control, the concentration of carbon dioxide in blood or further in gas can be measured at the outlet as a process parameter. In this case, both controls are performed in compliance with the condition that a pressure difference of the type according to the present invention exists.

[0059] More preferably, in the exchange chamber, it is possible to intend that the axial length of the multiple hollow fibrous membranes is greater than the length of the chamber in the direction of separation of the ends of the hollow fibrous membranes. Thus, the hollow fibers are not linearly extended but are bulging, and a medium flowing around them, such as a gas, can flow more smoothly.

[0060] One advanced form may also involve a pulsating device that can generate repeated, and particularly periodic, pressure fluctuations in the liquid exchange medium during operation, through a chamber region passing inside a hollow fibrous membrane, preferably through a duct that guides a liquid exchange medium, particularly blood. This has the advantage of reducing the thickness of the blutplasmasaum inside the hollow fibers.

[0061] The present invention may also envision a combination of at least two of the above-described variants of devices, preferably connected in series or in parallel in the flow direction of the liquid exchange medium, such that at least one device operates with a positive pressure difference and at least one device operates with a negative pressure difference relative to atmospheric pressure, or one device operates with a pressure difference and the other device operates without a pressure difference.

[0062] In particular, in such combinations, it is possible to intend for at least two devices to operate at different gas-to-blood flow ratios (GBV), in which case the gas-to-blood ratio GBV is defined as GBV = gas flow / blood flow. Preferably, the gas-to-blood ratio GBV in devices operating at negative pressure differences, especially in devices for CO2 removal, is greater than that of devices operating at positive pressure differences, especially in devices for oxygen enrichment. Preferably, the devices for CO2 removal operate at GBV > 1, e.g., 1 to 15, and the devices for oxygen enrichment operate at GBV < 1. [Brief explanation of the drawing]

[0063] [Figure 1] This is a schematic diagram of an apparatus according to the present invention that exchanges gas between a first exchange medium, in this case blood, and a second gaseous exchange medium, in this case pure oxygen or an oxygen-containing gas. [Figure 2A] This diagram shows a silicone layer on the inside. [Figure 2B] This diagram shows a silicone layer on the outside. [Figure 3] This figure shows the operation of the present invention with respect to pressure that can be changed by the control device. [Figure 4] The diagrams show the oxygen transport rate (OTR) on the left and the carbon dioxide transport rate (CTR) on the right, relative to blood flow rate. [Figure 5] This figure shows the possible configurations and developmental forms shown in Figure 1. [Figure 6] This figure shows another alternative form of the apparatus according to the present invention. [Figure 7] This figure shows a modified version of the embodiment shown in Figure 6. [Figure 8] This figure shows the effect of changes in gas flow rate during CO2 removal. [Figure 9] This figure shows an embodiment that is substantially the same as Figure 6. [Figure 10] This figure shows another modified implementation where the partial pressure is measured depending on the target concentration of CO2 in the blood when a pressure difference representing negative pressure relative to atmospheric pressure exists. [Figure 11] This figure shows an embodiment in which the volumetric flow rate is changed by a control device when negative pressure is present. [Figure 12A] This diagram shows a combination of two exchange devices connected by a negative pressure unit. [Figure 12B] This figure shows an embodiment in which two devices according to the present invention are connected by being connected in series in the direction of blood flow. [Figure 12C] This diagram shows an alternative structural configuration for two devices connected in series. [Figure 13] This figure shows one embodiment of the apparatus according to the present invention, which has no interconnections in the pipeline. [Figure 14] This figure shows a deformation morphology in which the axial length of the hollow fibrous membrane is greater than the length of the chamber in the direction of separation at the ends of the hollow fibrous membrane.

[0064] Exemplary embodiments of the present invention are described below.

[0065] Figure 1 schematically illustrates an apparatus according to the present invention for gas exchange between a first exchange medium, in this case blood, and a second gaseous exchange medium, in this case pure oxygen or an oxygen-containing gas, comprising an exchange unit having an exchange chamber 1 located within the housing of the exchange unit and a membrane 2 designed as a hollow fiber that divides the exchange chamber 1 into two chamber regions. The first chamber region surrounds the inside of the hollow fiber 2, and the second chamber region surrounds the outside of the hollow fiber 2. Thus, blood flows through the first chamber region and the hollow fibrous membrane 2, while gas flows through the second chamber region and outside the membrane.

[0066] Both chamber regions are incorporated into conduits 3 and 4. The first conduit 3 carries blood, and the second conduit 4 carries gas. Both conduits 3 and 4 have inlets and outlets to their respective chamber regions. At least the blood circulates in a circuit between a patient (not shown here) and the illustrated apparatus. The gas flows from a pressure generator 9a, e.g., a gas source, through the apparatus to a gas sink 9b, e.g., the surrounding environment. Here again, a circuit can be formed, for example, when used gas is recovered.

[0067] Each membrane 2 is designed as shown here, and in other exemplary embodiments, for example, as shown in Figure 2A or Figure 2B. The membrane 2 has a continuous porous support element formed, for example, from a prior art porous hollow fiber, such as polysulfone, polypropylene, or polymethylpentene, and here, on the inside in Figure 2A and on the outside in Figure 2B, there is a silicone layer 2a here, for example, with a thickness of about 7.5 micrometers.

[0068] Such coated hollow fibers 2 are diffusively permeable to, for example, oxygen and carbon dioxide, but do not allow gas bubbles or liquid components of the first exchange medium to pass through the film thickness by convection; that is, they remain airtight with respect to convection even when the gas is at a positive pressure relative to the first chamber region or the atmospheric pressure at the location of the apparatus in the second chamber region or second conduit through which the gas is introduced. This airtightness (Dichtigkeit) is achieved only by a layer of silicone or a suitable alternative material. In contrast, porous support elements are not airtight with respect to convection of the second exchange medium relative to atmospheric pressure, or of the two exchange mediums if a pressure difference exists between the two chamber regions; that is, they allow gas bubbles to pass through, for example.

[0069] As shown in Figures 2A and 2B, the silicone layer 2a can be provided on the inside or outside, or the hollow fibers 2 can be formed entirely of silicone, particularly non-porous silicone or other suitable convective-dense material.

[0070] What is important to the present invention is that at least one measuring device 5 is provided after the blood outlet in the blood conduit 3, thereby enabling the measurement of values ​​representing process parameters.

[0071] According to Figure 1, a first measuring device 5a is provided to measure, for example, the oxygen concentration in the blood as a first measurement value, for example, by measuring O2 saturation or O2 partial pressure. A second measuring device 5b is further provided to measure, for example, the carbon dioxide concentration in the blood as a second measurement value, for example, by measuring CO2 concentration or CO2 partial pressure.

[0072] Contrary to what is shown in the diagram, it is also possible to assume that only one of the two measuring devices mentioned above is formed.

[0073] The first measured value is compared as an actual value in the control device 6a with process parameters, such as a target value for oxygen concentration, such as a target partial oxygen pressure. To achieve the target value, the control device 6a controls a gas pressure regulator 7 in the second pipeline 4 at the gas outlet of the second chamber region, which can be designed as, for example, a throttle valve. Therefore, the control device 6a in the second pipeline is formed by at least the gas pressure regulator 7. The valve position of the throttle valve can form the adjustment amount of the control device 6a.

[0074] The second measured value is compared as an actual value in the control device 6b with process parameters, such as a target value for carbon dioxide concentration, such as a target partial pressure of carbon dioxide. To achieve the target value, the control device 6b controls a gas flow regulator 8 in the second pipeline 4 of the gas inlet of the second chamber region, which can be designed as, for example, a throttle valve. Thus, the control device 6b in the second pipeline is formed by at least the gas flow regulator 8. The valve position of the throttle valve can form the adjustment amount of the control device 6b.

[0075] A gas source 9a, such as a gas cylinder or pump, is placed at the gas inlet, thereby forming a pressure generating device in the second pipeline 4. By narrowing or widening the gas flow on the gas outlet side and / or gas inlet side, the pressure and / or volumetric flow rate of the gas, i.e., the second exchange medium in the second chamber region, is affected, and the pressure is adjusted to a higher differential pressure, for example, at least 10 mmHg higher according to the present invention. Therefore, the control device is preferably also part of the pressure generating device that generates the pressure and / or flow of the second exchange medium.

[0076] Figure 3 illustrates the operation of the present invention with respect to pressure that can be changed by the control device.

[0077] Here, ordinary ambient air with an oxygen content of approximately 20.8 percent is used as the second exchange medium. Atmospheric pressure has been confirmed to be 760 mmHg, for example, by measurement.

[0078] This diagram shows that as positive pressure increases, the partial pressure of oxygen, which is a measure of oxygen concentration in the gas phase, rises significantly, for example, from 158 mmHg at atmospheric pressure to 366 mmHg when the positive pressure is 1000 mmHg.

[0079] At the blood outlet, process parameters such as oxygen concentration can be measured, and a desired value of the process parameter, such as a desired concentration value, can be selected or controlled by changing the positive pressure difference with respect to that value.

[0080] Figure 4 supplementarily illustrates the effects of the present invention at various blood flow rates.

[0081] Figure 4 shows the oxygen transport rate (OTR) on the left and the carbon dioxide transport rate (CTR) on the right, both relative to blood flow rate. The pressure is +300 mmHg relative to atmospheric pressure, for the second exchange medium, which is oxygen or an oxygen-containing gas. It can be seen that the oxygen transport rate at positive pressure is faster than at atmospheric pressure for all blood flow rates.

[0082] As shown in the right-hand diagram of Figure 4, the transport velocity of carbon dioxide under these positive pressure conditions is lower than under normal pressure, but this can be compensated for by a higher gas flow rate, as shown in the embodiment of Figure 1, for example.

[0083] In this application of blood oxygen enrichment using the apparatus shown in Figure 1, measuring devices for measuring process parameters, such as oxygen concentration and / or carbon dioxide concentration, and control devices, in this case a gas pressure regulator 7 or a gas flow regulator 8, are located in different pipelines, both on the outlet side of their respective chamber regions.

[0084] Figure 1 shows a preferred advanced form of the present invention, as described above, in which a second control device is located in the pipeline 4 for introducing the second gaseous exchange medium, and in this case a gas flow regulator 8 is located on the inlet side of the second chamber region, and the second process parameter is measured. This allows for a controllable influence on the volumetric flow rate of the second exchange medium. This can be done independently of differential pressure control, particularly depending on the second process parameter, and in parallel with this differential pressure control, but especially when measuring only one process parameter, it can be done while maintaining a predetermined, particularly maximum, differential pressure.

[0085] This makes it possible to further increase the concentration by post- or standalone control of the gas volumetric flow rate, especially when the differential pressure cannot be increased further to achieve the target value of a single process parameter, such as carbon dioxide concentration or oxygen concentration. For example, after reaching the maximum pressure difference, or after adjusting to a desired pressure difference that does not need to correspond to the maximum pressure difference, it may be intended that this pressure difference is not increased further or is kept constant, and that the volumetric flow rate is changed to control or approximate the target value.

[0086] The present invention may also be intended to control only the volumetric flow rate when a differential pressure of at least 10 mmHg exists relative to atmospheric pressure, particularly when it is kept constant.

[0087] Figure 5 shows a possible advanced configuration of the setup shown in Figure 1, in which, for example, a negative pressure unit is connected downstream of the apparatus in Figure 1, in the blood conduit 3 after the blood outlet. In this negative pressure unit, the blood conduit 3 is adjacent to a porous flat membrane, and a negative pressure chamber is located on the side of this membrane opposite to the blood. The negative pressure chamber is controlled to a negative pressure relative to atmospheric pressure by a negative pressure regulator, depending on the measurement of a bubble detector that checks whether bubbles are present in the blood, and how many bubbles are present. Therefore, if bubbles are unexpectedly present in the blood after the blood outlet of the exchange chamber 1, they are removed through the flat membrane, and the negative pressure required for this is automatically controlled.

[0088] Figure 6 shows another alternative embodiment of the apparatus according to the present invention. In this embodiment, the tubing is formed through the exchange chamber as in Figure 1, but here, for example in an exemplary application, it operates using a differential pressure having a negative differential pressure value relative to atmospheric pressure to remove CO2 from blood; that is, this is performed using negative pressure in the second chamber region.

[0089] Both the measuring device 5b and the pressure control device 7 are implemented in the same conduit, that is, in this case, in the conduit 4 for a gaseous exchange medium such as oxygen or an oxygen-containing gas. In this case, the measuring device 5 is located on the outlet side of the second chamber region. Here, the CO2 concentration is measured as the partial pressure of the gas after it leaves the second chamber region. Alternatively, the blood concentration could also be measured at the outlet of the first chamber region.

[0090] Negative pressure is generated when a negative pressure pump / vacuum pump discharges the second exchange medium supplied by the gas source 9a from the second chamber region. The negative pressure pump forms a gas sink and a pressure generating device capable of generating a pressure difference. Pressure control can be performed, for example, by controlling the power of the vacuum pump, or by controlling a pressure regulator, such as a throttle valve 7, particularly on the inlet side of the second chamber region, depending on process parameters such as concentration measurements. The pressure regulator 7 is also part of the pressure generating device and affects the pressure generated by the pressure generating device.

[0091] Here too, for example, if the differential pressure cannot be reduced any further, or if it is necessary to control two different process parameters as shown in Figure 1, the volumetric flow rate of the gas can be additionally changed in parallel / following / preceding, or independently using the flow regulator 8.

[0092] In particular, this device is configured to maintain a constant differential pressure when changing the volumetric flow rate. The volumetric flow rate of the second exchange medium can also be controlled independently with a constant differential pressure having a difference of at least 10 mmHg relative to atmospheric pressure according to the present invention.

[0093] Figure 7 shows a modified embodiment of Figure 6, in which the carbon dioxide concentration in the blood is measured using a measuring device at the blood outlet of the first chamber region, and the negative pressure unit is controlled depending on this value, thereby changing the differential pressure, again negative pressure relative to atmospheric pressure, to achieve a desired target value in the blood.

[0094] Furthermore, it is possible to recognize the possibility of removing the absorbed CO2 from the gas flowing through the second chamber region and the gas that has absorbed CO2, for example by an absorber, and to utilize the gas in the circuit, i.e., to send it again through the device. For example, if oxygen is removed from the gas circuit due to enrichment in the blood, this oxygen can be added to the circuit. To this end, the oxygen concentration in the blood can be measured at the blood outlet of the first chamber region and controlled by replenishing oxygen.

[0095] Figure 8 shows the effect of significant gas flow rate changes, particularly in the application of CO2 removal. Figure 4, on the right, shows that when the pressure increases, the O2 transport rate increases, but the CO2 transport rate decreases.

[0096] Figure 8 shows that when negative pressure, i.e., a negative pressure difference according to the present invention, is used, the CO2 transport rate increases significantly with increasing gas flow rate, especially when blood flow is constant at, for example, 0.35 liters / minute.

[0097] Furthermore, with a gas flow rate of 0.7 L / min, the CO2 transport velocity increases with respect to this constant value at different pressure differences of -10, -100, -300, and -500 mmHg relative to atmospheric pressure. Thus, for example, in negative pressure operation for CO2 removal, it can be seen that the transport velocity of carbon dioxide increases by both changing the pressure difference in the direction of increasing the negative pressure difference and increasing the gas flow rate. Therefore, to increase the transport velocity, either of these two mechanisms can be used alone or in combination, preferably in both cases, by changing adjustment amounts that affect the pressure difference and / or volumetric flow rate, for example, to control the transport velocity to a target value, such as a value dependent on the CO2 concentration.

[0098] Figure 9 shows substantially the same embodiment as Figure 6, but here the CO2 transfer rate is calculated as a process parameter.

[0099] Figure 10 shows another modified implementation where, in the presence of a pressure difference exhibiting negative pressure relative to atmospheric pressure, the CO2 concentration in the blood is measured as a partial pressure depending on the target concentration. The device is initially set to change, and in particular increase, the volumetric flow rate of a second gaseous exchange medium, in this case oxygen or an oxygen-containing gas, in order to achieve the target value.

[0100] This control is preferably carried out until a predetermined blood:gas flow rate ratio, for example 1:15, is reached, and from that point onward the gas pressure is reduced, and in particular in order to achieve a target concentration, i.e., the amount of differential pressure with the atmosphere is increased in negative pressure application.

[0101] Figure 11 shows an embodiment in which, as a process parameter, a vacuum pump is used as a pressure generator to generate negative pressure in the second chamber region in order to obtain a predetermined blood:gas or gas:blood flow rate ratio, and when negative pressure is present, the volumetric flow rate is changed by a control device in the form of at least one gas flow regulator in the second pipeline. For this purpose, a blood flow measurement is preferably detected and associated with the detected gas flow rate measurement.

[0102] Figure 12A here preferably shows a combination of two exchange devices connected by a negative pressure unit that can optionally remove gas bubbles, as shown in Figure 1. The negative pressure unit has a common blood outlet for the two devices, which have separate blood inlets. At least one of the devices, which operates by a pressure difference, in this case positive pressure, is designed according to the present invention. The other device can be designed according to the prior art, for example, as described in the premise of claim 1.

[0103] Figure 12B shows an embodiment in which two devices according to the present invention are connected in series, for example, by connecting them one behind the other in the direction of blood flow, and the two devices have a radial gas flow.

[0104] In the blood flow direction, the first (in this case, lower) device performs CO2 removal at a higher gas flow rate (preferably air) than the second (in this case, upper) device in the blood flow direction when negative pressure relative to atmospheric pressure is present, and O2 enrichment is performed when positive pressure relative to atmospheric pressure is present (gas phase: preferably oxygen). In this case, different hollow fiber membranes, particularly those with different diameters, can be used in the two devices.

[0105] Figure 12C shows a structural alternative configuration of two sequentially connected devices in series, where the second device is radially positioned around the first device, and blood flow is guided from the radially inward, first through the first device and then through the second device. Thus, these devices have a common blood conduit but also radially separated gas conduits, each extending axially with respect to the hollow fiber direction.

[0106] Here, in the first device on the radially inner side in the blood flow direction, negative pressure is applied to remove CO2 at a higher gas flow rate (preferably air) than when O2 enrichment is performed by negative pressure application in the second device on the radially outer side in the blood flow direction (gas phase: preferably oxygen).

[0107] In particular, the porosity of the hollow fibers is selected differently in both devices, and is higher in the first device than in the second device, especially in the blood flow direction.

[0108] Figure 13 shows, for example, one embodiment of the apparatus according to the present invention, which has no interconnections in the tubing as described above. The tubing, which guides a liquid exchange medium, particularly blood, during operation, is equipped with a pulsating device that passes through a chamber region, preferably through the inside of a hollow fibrous membrane. This pulsating device can be used to repeatedly generate, particularly periodically, pressure fluctuations in the liquid exchange medium as shown in the graph, thereby preventing a constant blood volume flow rate, which is advantageous in preventing the formation of plasma edges on the surface of the membrane.

[0109] Figure 14, supplementarily and for use in all possible embodiments, shows a modification in which the axial length of multiple hollow fibrous membranes in the exchange chamber is greater than the length of the chamber in the direction of separation of the ends of the hollow fibrous membranes. This can improve the ambient flow. Preferably, the gas flow is directed radially relative to the extension of the hollow fibers.

Claims

1. A device for exchanging gas between a first exchange medium and a second gaseous exchange medium, comprising an exchange unit having an exchange chamber (1) located within the housing of the exchange unit, a. The exchange chamber (1) is divided by at least one membrane (2), preferably a plurality of hollow fibrous membranes (2), into a first chamber region where the first side of the at least one membrane (2) can contact the first exchange medium, and a second chamber region where the second side of the at least one membrane (2) can contact the second gaseous exchange medium. b. The first chamber region has an inlet connection and an outlet connection for the first exchange medium, and the first chamber region is incorporated into the first conduit (3) by the inlet connection and the outlet connection, and the first exchange medium can be guided through the first chamber region using the first conduit (3). c. The second chamber region has an inlet connection and an outlet connection for the second gaseous exchange medium, and the second chamber region is incorporated into the second conduit (4) by the inlet connection and the outlet connection, and the second exchange medium can be guided through the second chamber region using the second conduit (4). d. In a device capable of transferring the gas to be exchanged, present in one of the two exchange media, across at least one membrane (2) into the other exchange medium by diffusion, e. The apparatus is equipped with a pressure generating device (9a), and the pressure generating device (9a) is capable of generating a pressure difference of at least 10 mmHg of the second exchange medium relative to the ambient atmospheric pressure in the second chamber region, particularly through the second pipe (4), and is particularly generated during gas exchange operation. f. The at least one membrane (2) is permeable to diffusion with respect to the gas to be exchanged, in the case of the pressure difference that can be generated, and impermeable to convection with respect to both exchange media, in the case of the pressure difference that can be generated. An apparatus characterized by the following features.

2. The apparatus according to claim 1, wherein the apparatus comprises at least one measuring device (5a, 5b) for measuring an actual value of at least one process parameter in at least one of the exchange media, the apparatus particularly comprises at least one control device (6a, 6b) in the second pipeline (4), and the measured actual value of the at least one process parameter can be changed toward a predetermined target value of the at least one process parameter by using the control devices (6a, 6b) to change the pressure and / or volumetric flow rate of the second exchange media in the second chamber region as an adjustment amount.

3. The apparatus according to claim 1 or 2, characterized in that the apparatus is configured to control or approximate a process parameter, particularly a concentration, or a value dependent on the process parameter, particularly a concentration, of the gas to be exchanged in the first exchange medium and / or second exchange medium to a desired, particularly preset, target value, depending on the pressure and / or volumetric flow rate of the second exchange medium.

4. In the flow direction, after the outlet connection, in one of the two chamber regions of the pipeline (3, 4), at least one measuring device (5a, 5b) is provided for measuring a measurement value representing at least one process parameter. In particular, the measured value represents, or depends on, the concentration of the gas to be exchanged in the exchange medium in the chamber region. At least one control device (6a, 6b) is provided in the second conduit (4) of the second chamber region, and the control device (6a, 6b) is used to determine the measurement value, a. The value of the pressure difference and / or b. The value of the volumetric flow rate of the second exchange medium can be changed, The apparatus according to any one of claims 1 to 3, characterized by the above.

5. The apparatus according to any one of claims 1 to 4, characterized in that the apparatus is configured to adjust or control a pressure difference of an amount greater than 10 mmHg, preferably greater than 20 mmHg, preferably greater than 50 mmHg, more preferably greater than 100 mmHg, more preferably greater than 200 mmHg, more preferably greater than 300 mmHg, more preferably greater than 400 mmHg, more preferably greater than 500 mmHg, particularly less than 700 mmHg, preferably less than 600 mmHg, especially during operation.

6. The apparatus according to any one of claims 1 to 5, characterized in that the at least one membrane (2) that is permeable to the gas to be exchanged has a layer on at least one side, particularly on the side in contact with the liquid exchange medium, preferably on the inside of the at least one hollow fibrous membrane (2), that prevents the convection passage of the exchange medium, or is continuously formed as a membrane that prevents convection passage.

7. The apparatus according to claim 6, characterized in that the layer or film (2) can withstand a pressure difference of a quantity greater than 10 mmHg, preferably greater than 20 mmHg, preferably greater than 50 mmHg, more preferably greater than 100 mmHg, more preferably greater than 200 mmHg, more preferably greater than 300 mmHg, more preferably greater than 400 mmHg, and more preferably greater than 500 mmHg, but particularly less than 700 mmHg, preferably less than 600 mmHg, without being destroyed.

8. The apparatus according to claim 6 or 7, wherein the at least one layer is formed of a non-porous, particularly discontinuous porous material, preferably silicone, that allows the diffusion of the gas to be exchanged, or the at least one membrane is entirely formed of a non-porous, particularly discontinuous porous material, preferably entirely formed of silicone, and the at least one membrane (2) has a layer of silicone on at least one side, and comprises a porous support element, particularly porous hollow fiber, having a minimum thickness of 2 micrometers, more preferably a minimum thickness of 3 micrometers, more preferably a minimum thickness of 4 micrometers, and more preferably a minimum thickness of 5 micrometers.

9. The at least one control device (6a, 6b) and the at least one measuring device (5a, 5b) for measuring the at least one process parameter are: a. The apparatus is located in the pipelines (3, 4) of different chamber regions, and in particular, the apparatus is configured to have a liquid exchange medium as a first exchange medium in the first chamber region connected to the measuring devices (5a, 5b), preferably the outlet-side measuring device, during operation, and the control devices (6a, 6b) are located in the pipeline (4) of the second chamber region, which is configured to have the gaseous second exchange medium during operation of the apparatus, preferably located on the outlet side, and more preferably, the control devices (6a, 6b) are configured to control the positive pressure in the second chamber region relative to atmospheric pressure, or b. Located in the same pipeline (3, 4), particularly in the pipeline (4) of the second chamber region configured to have the gaseous second exchange medium during operation of the apparatus, preferably the apparatus is configured to have a liquid exchange medium in the chamber region having the first exchange medium during operation, and more preferably the control devices (6a, 6b) are configured to control negative pressure with respect to atmospheric pressure. The apparatus according to any one of claims 1 to 8, characterized in that

10. The aforementioned device is a. The device is configured to enrich the oxygen in the blood as the first exchange medium, or to deplete the carbon monoxide, and for that purpose, the at least one measuring device (5a) is configured to measure the concentration of oxygen in the blood, in particular the partial pressure of oxygen, or the concentration of carbon monoxide, in particular the partial pressure of carbon monoxide, and is located in the conduit (3) after the outlet connection of the first chamber region provided for guiding the blood, in particular the chamber region being adjacent to the inner surface of a plurality of hollow fibrous membranes, b. The device is configured for the operation of depleting carbon dioxide in the blood as a first exchange medium, and for that purpose, the at least one measuring device (5b) is configured to measure the concentration of carbon dioxide in the gaseous second exchange medium, particularly the partial pressure of carbon dioxide, and is located in the conduit (4) after the outlet connection of the chamber region provided for guiding the gaseous second exchange medium, particularly the chamber region adjacent to the outer surface of the plurality of hollow fibrous membranes (2). The apparatus according to any one of claims 1 to 9, characterized in that

11. The apparatus according to any one of claims 1 to 10, characterized in that, as a process parameter, a predetermined target partial pressure of the gas to be exchanged or a target value dependent on the partial pressure of the gas to be exchanged can be controlled by controlling the pressure using at least one control device (6a, 6b).

12. The apparatus according to any one of claims 1 to 11, wherein the volumetric flow rate of the exchange medium in the second pipeline (4) can be changed using the at least one control device (6a, 6b) depending on the at least one measured value and further depending on the amount of the pressure difference, and the control devices (6a, 6b) are set to increase the volumetric flow rate, in particular while keeping the pressure difference constant, when the limit value of the pressure difference is exceeded.

13. The apparatus according to any one of claims 1 to 12, characterized in that, in the exchange chamber (1), the axial length of the plurality of hollow fibrous membranes is greater than the length of the exchange chamber (1) in the direction of separation of the ends of the hollow fibrous membranes (2).

14. The apparatus according to any one of claims 1 to 13, characterized in that the conduit (3) which guides a liquid exchange medium, particularly blood, during operation, and which passes through a chamber region preferably passing inside the hollow fibrous membrane (2), is equipped with a pulsating device capable of repeatedly, particularly periodically, generating pressure fluctuations in the liquid exchange medium.

15. A combination of at least two devices according to any one of claims 1 to 14, preferably connected in series or in parallel in the flow direction of a liquid exchange medium, characterized in that at least one device operates with a positive pressure difference and at least one device operates with a negative pressure difference, or one device operates with a pressure difference and the other device operates without a pressure difference.

16. A method for exchanging gas between a first exchange medium other than blood and a second gaseous exchange medium, using an exchange unit having an exchange chamber (1) located within the housing of the exchange unit, a. The exchange chamber (1) is divided by at least one membrane (2), preferably a plurality of hollow fibrous membranes (2), into a first chamber region in which the first side of the at least one membrane (2) is in contact with the first exchange medium, and a second chamber region in which the second side of the at least one membrane (2) is in contact with the second gaseous exchange medium. b. The first chamber region has an inlet connection and an outlet connection for the first exchange medium, and the first chamber region is incorporated into the first conduit (3) by the inlet connection and the outlet connection, and the first exchange medium is guided through the first chamber region using the first conduit (3). c. The second chamber region has an inlet connection and an outlet connection for the second gaseous exchange medium, and the second chamber region is incorporated into the second pipeline (4) by the inlet connection and the outlet connection, and the second exchange medium is guided through the second chamber region using the second pipeline (4). d. In a method in which the gas to be exchanged, present in one of the two exchange media, is transferred by diffusion across at least one membrane (2) into the other exchange medium, e. Using the pressure generating device (9a), a pressure difference of at least 10 mmHg of the second exchange medium relative to the ambient atmospheric pressure is generated in the second chamber region, particularly through the second conduit (4), especially during gas exchange operation. f. The at least one membrane (2) is permeable to diffusion with respect to the gas to be exchanged, given the generated pressure difference, and is impermeable to convection with respect to both exchange media, given the generated / generated pressure difference. A method characterized by the following features.

Images