DEVICE FOR REMOVING A GAS FROM AN AQUEOUS LIQUID

Abstract

The invention relates to a device for removing a gas from an aqueous liquid, particularly a blood liquid, comprising a first compartment permeated by the aqueous liquid during operation of the device; a second compartment permeated by a purging gas during operation of the device, the first compartment and the second compartment being separated from each other by a semipermeable membrane; and a third compartment permeated by a liquid proton donor during operation of device, said proton donor being an organic or inorganic acid, the first compartment and the third compartment being separated from each other by a membrane permeable to ions, and the membrane permeable to ions comprising at least one cation conductor.

Claims

1. A device for removing a gas from an aqueous liquid, comprising: a first compartment permeated by a blood liquid, preferably blood, during operation of the device; a second compartment permeated by a purging gas during operation of the device, the first compartment and the second compartment being separated from each other by a semipermeable membrane; and a third compartment permeated by a liquid proton donor during operation of the device, said proton donor being an organic or inorganic acid, the first compartment and the third compartment being separated from each other by a membrane permeable to ions, the membrane permeable to ions comprising at least one cation conductor.

2. The device according to claim 1, the carbon dioxide dissolved in the blood liquid reacting with hydrogen ions of the proton donor and forming carbonic acid due to the interaction between the blood liquid and the liquid proton donor through the membrane permeable to ions, the hydrogen ions diffusing through the membrane permeable to ions out of the liquid proton donor into the blood liquid.

3. The device according to claim 1 or 2, the arising carbonic acid decomposing into water and carbon dioxide for transporting away by the purging gas of the second compartment.

4. The device according to any one of the claims 1 through 3, the second compartment comprising a plurality of lines, preferably hollow fibers, made of the semipermeable material.

5. The device according to any one of the claims 1 through 4, the third compartment comprising a plurality of lines, preferably hollow fibers, made of the membrane permeable to ions.

6. The device according to any one of the claims 1 through 5, the membrane permeable to ions comprising a cation and anion conductor.

7. The device according to any one of the claims 4 through 6 and referencing the claims 3 and 4, the lines of the second compartment and the lines of the third compartment being present in the first compartment, except for the inlets and outlets thereof.

8. The device according to any one of the claims 4 through 7 and referencing the claims 3 and 4, the lines of the second compartment and the lines of the third compartment always being separated from each other by a partial volume of the first compartment.

9. The device according to any one of the claims 4 through 8, the first compartment comprising an inlet and an outlet in order to guide the aqueous liquid through the first compartment, the inlet and the outlet being disposed such that a flow of blood through the first compartment can be adjusted during operation of the device.

10. A composition comprising a liquid proton donor and permeating the third compartment of a device according to any one of the claims 1 through 9 for use in a method for treating hypercapnia.

11. A use of a composition comprising a liquid proton donor and permeating the third compartment of a device according to any one of the claims 1 through 9 for treating hypercapnia.

12. The composition according to claim 10 or use according to claim 11, the liquid proton donor being a preferably non-toxic acid or comprising an acidic buffer solution.

13. The composition according to claim 10 or 12 or use according to claim 11 or 12, at least one physiologically relevant type of metal cation being present in the liquid proton donor in at least a physiological concentration; and no sodium being preferably present in the liquid proton donor.

14. The composition according to any one of the claim 10, 12, or 13, or use according to any one of the claims 11 through 13, the composition further comprising a purging gas permeating the second compartment of the device according to any one of the claims 1 through 8.

15. The composition according to any one of the claims 10, 12 through 14, or use according to any one of the claims 11 through 14, the treatment comprising the following steps: providing a flow of aqueous liquid through the first compartment; providing a flow of the purging gas through the second compartment; providing a flow of the liquid proton donor through the second compartment.

Description

[0029] Preferred embodiment examples of the invention are described in more detail below using the attached drawings.

[0030] FIG. 1 shows the schematic structure of a device for removing a gas from an aqueous liquid according to various embodiment examples.

[0031] FIG. 2 shows a schematic view of the three compartments and the chemical reactions occurring during operation of the device according to the invention.

[0032] FIGS. 3A through 3C show potential locations of the three compartments of the device according to the invention relative to each other.

[0033] FIG. 1 shows a side view of a schematic structure of the device 1 according to the invention for removing a gas from an aqueous liquid. The depiction focuses on the interaction space of the device 1, that is, the region in which the substances in the corresponding compartments can interact with each other; the other fluidic components (lines, pumps, sensors, etc.) are not depicted. The device 1 comprises a first compartment 2, a second compartment 3, and a third compartment 4. Each of the compartments 2, 3, 4 comprises two connections: the first compartment 2 comprises a first connection 21 and a second connection 22, the second compartment 3 comprises a third connection 31 and a fourth connection 32, and the third compartment 4 comprises a fifth connection 41 and a sixth connection 42. One connection of each of the compartments 2, 3, 4 functions as an inlet during operation of the device according to the invention and the corresponding other connection functions as an outlet, depending on the direction in which the corresponding substance permeates the corresponding compartment. A pump, for example, can be disposed between each pair of connections of a compartment 2, 3, 4 in order to maintain circulation of the substance.

[0034] The first compartment 2 permeated by the aqueous liquid can comprise any arbitrary shape, for example a cylindrical shape as shown in FIG. 1. One connection each can be disposed near the floor and near the cover of a compartment. The second compartment 3 comprises a plurality of first lines 33, preferably hollow fibers, providing a fluid connection between the third connection 31 and the fourth connection 32. The third connection 31 and the fourth connection 32 each open into a reservoir in the top and in the bottom region of the interaction space of the device 1, wherein said reservoir is not a necessary feature, wherein each reservoir in the embodiment example shown extends over the entire base surface of the interaction space. The first lines 33 connect the two reservoirs to each other. In an analogous manner, the third compartment 4 comprises a plurality of second lines 43, preferably hollow fibers, disposed between the fifth connection 41 and the sixth connection 42. The fifth connection 41 and the sixth connection 42 each open into a reservoir in the top and in the bottom region of the interaction space of the device 1, wherein each reservoir in the embodiment example shown extends over the entire base surface of the interaction space 1. Because the reservoirs of the second compartment 3 enclose the reservoirs of the third compartment 4 or are disposed above and below the same as viewed from outside, the first lines 33 run through the reservoirs of the third compartment 4. To this end, the second lines 43 of the third compartment 4 are advantageously longer in design than the first lines 33 of the second compartment 3, because the first lines also run through the reservoirs of the third compartment 4. A plan view of a cross section Q in the center region of the interaction space is shown on the right side of the side view of the interaction space of the device 1. The cross section view Q shows that the first lines 33 of the second compartment 3 and the second lines 43 of the third compartment 4 each run through the first compartment 2 spaced apart from each other by a distance. The first lines 33 and the second lines 43 are also disposed spaced apart from each other by a distance in the volume of the first compartment 2.

[0035] It is noted that the arrangement and location of the second compartment 3 and of the third compartment 4, as shown in FIG. 1, embodies one of many potential arrangements. In a further embodiment example, the location of the second and third compartments 3, 4, as shown in FIG. 1, can be swapped with each other. Furthermore, the flow direction (from top to bottom or from bottom to top in FIG. 1) of the substance flowing in each of compartments 2, 3, 4 can generally be adjusted individually and independently of the other two compartments in each case. The quantity and the cross section of the first lines 33 and the second lines 43 can be selected as needed.

[0036] FIG. 2 shows the chemical processes occurring during operation of the device 1 according to the invention between the first and second compartment 2, 3 and between the first and third compartment 2, 4. The first compartment 2 is permeated by the aqueous liquid, preferably blood, from which a gas, preferably carbon dioxide, is to be removed. Physically dissolved carbon dioxide is present in the blood liquid. In addition, physiologically relevant metal cations are present in the blood liquid at the corresponding physiological concentration of each. Said metal cations are bound in bicarbonate compounds. At the same time, carbon dioxide is chemically bound in the bicarbonate compounds.

[0037] The purging gas, typically comprising pure oxygen (O.sub.2) flows through the second compartment 3. The semipermeable membrane 5 is disposed between the first compartment 2 and the third compartment 3. Due to a concentration gradient between the first compartment 2 and the second compartment 3 with respect to carbon dioxide (CO.sub.2), the carbon dioxide physically bound in the blood 7 is released and diffuses across the semipermeable membrane 5 into the second compartment 3. In return, oxygen diffuses out of the purging gas, across the semipermeable membrane 5, into the blood liquid, and is received by the erythrocytes 7 therein. Said procedure is well known from typical ECMO applications and is sketched in the first marked region 8.

[0038] The carbon dioxide chemically bonded in the bicarbonate compounds is released from the bicarbonate compounds by means of the liquid proton donor permeating the third compartment 4. A cation exchange occurs through the membrane 6 permeable to ions disposed between the first compartment 2 and the third compartment 4, and said exchange is further sketched in the second marked region 9. Said procedure is also induced by a concentration gradient with respect to an exchange ion. In the embodiment example shown for oxygenation of blood, the exchange ion is sodium (Na.sup.+), the target exchange ion in the example shown. The sodium diffuses through the membrane 6 permeable to ions into the (low-sodium) third compartment 4. In return, hydrogen cations present in the liquid proton donor diffuse out of the third compartment 4 into the first compartment 2. The hydrogen cation bonds to the bicarbonate (HCO.sup.−.sub.3), whereby carbonic acid (H.sub.2CO.sub.3) is formed, but is unstable and ultimately relatively quickly decomposes into water (H.sub.2O) and carbon dioxide. The carbon dioxide molecule thus released crosses the semipermeable membrane 5 into the second compartment 3 in a manner analogous to the physically dissolved carbon dioxide molecules. The liquid proton donor in the third compartment 4 thereby serves for releasing the chemically bonded carbon dioxide, while the removing of the carbon dioxide thus released out of the blood liquid takes place, as previously, by means of the purging gas permeating the second compartment 3.

[0039] In general, there are many different possibilities for the design of the interaction space between the three substances, particularly for the spatial arrangement of the first lines 33 of the second compartment 3 and the second lines 43 of the third compartment 4 relative to each other and within the first compartment 2. Three fundamental embodiments are sketched in the FIGS. 3A through 3C. A bar in each of the figures represents a compartment in the interaction region of the device 1 and is correspondingly labeled with the reference numeral of the corresponding compartment. The longitudinal extent of each bar also defines the axis along which the corresponding compartment is permeated by the associated substance. Accordingly, two fundamental permeation flow directions arise for each compartment 2, 3, 4.

[0040] The embodiment sketched in FIG. 3A substantially corresponds to the embodiment of the device 1 according to the invention shown in FIG. 1, wherein the lines of the second compartment 3 and of the third compartment 4 are aligned parallel to each other and the flow directions of the substances through all three compartments 2, 3, 4 are aligned parallel to each other. The actual flow direction of the substance through each compartment can occur from top to bottom or from bottom to top, independently of the flow directions in the other two compartments. The location of the compartments 2, 3, 4 in the interaction region 1 sketched in FIG. 3A serves only for depicting the relative arrangement of the flow directions through the compartments relative to each other, so that the quantity of bars shown particularly does not correspond to the quantity of lines associated with a compartment. The quantity and the arrangement of the hollow channels forming the second compartment 3 and the third compartment 4 relative to each other can be implemented in various ways. One example of this is shown in the cross section view Q in FIG. 1, where it is evident that the first lines 33 form a hexagonal grid and the second lines 43 are disposed in the centers of the hexagons (except for the second lines 43 disposed on the edge). The lines of the second compartment 3 and of the third compartment 4 can further be disposed in alternating rows one after the other or adjacent to each other or in other geometric patterns.

[0041] According to the arrangement of the compartments 2, 3, 4 relative to each other shown in FIG. 3B, the flow direction of the aqueous liquid through the first compartment 2 is perpendicular to the flow directions of the substances through the second compartment 3 and through the third compartment 4. The arrangement of the lines of the second compartment 3 and of the fourth compartment 4 relative to each other can fundamentally correspond to one of the arrangements mentioned with respect to FIG. 3A.

[0042] Finally, a further potential embodiment of the interaction space of the device is shown in FIG. 3C, wherein the flow direction through the second compartment 3 and through the third compartment 4 are perpendicular to the flow direction through the first compartment 2. In a modification of the embodiment shown in FIG. 3B, however, the hollow channels of the second compartment 3 are additionally disposed at an angle a to the hollow channels of the first compartment 2, so that the flow directions are also correspondingly disposed at the angle a relative to each other. The angle a can preferably be 90°, for example. The lines of the second compartment 3 and the second lines of the third compartment 4 can thereby substantially implement a rectangular or square grid structure (from the point of view of the aqueous liquid permeating the first compartment 2), the intermediate spaces thereof being permeated by the aqueous liquid. The grid structure can be implemented such that the lines of the second compartment 3 and the lines of the third compartment 4 contact each other and thus implement intersection points of the grid-like structure. Alternatively, the lines of the second component 3 and the lines of the third compartment 4 can be disposed perpendicular to each other in rows, the rows being spaced apart from each other.