Abstract
The present invention relates to a gas exchange unit for use in extracorporeal membrane oxygenation (ECMO) or extracorporeal live support (ECLS) according to a method for producing such a gas exchange unit as well as a kit with a gas exchange unit and a humidifying and heating device.
Claims
1. A Gas exchange unit with a hollow-fibre module, characterised in that a gas flow characteristic of the hollow-fibre module is adaptable, wherein an overflow device is provided on the hollow-fibre module to allow different charging of fibre regions by means of differing pressure gradients, wherein the overflow device provides a plurality of gas-chambers connected together by gas-overflow-channels, wherein in addition to the overflow device an overlay is applied directly on a fibre bundle of a side surface of the hollow-fibre module, wherein the overlay is different from the overflow device; and wherein the overlay has a continuous pneumatic resistance gradient to increase the pneumatic resistance.
2. The gas exchange unit according to claim 1, characterised in that the hollow-fibre module is completely or partially connectable to or disconnectable from the gas flow.
3. The gas exchange unit according to claim 1, characterised in that on a gas side, said gas exchange unit has a shutter configured to regulate an amount of gas flow to the different fibre regions.
4. A Gas exchange unit according to claim 1, characterised in that the fibre regions of the hollow-fibre module can be differently charged with gas.
5. The gas exchange unit according to claim 1, characterised in that said gas exchange unit has a cover.
6. The gas exchange unit according to claim 5, characterised in that the cover has a pneumatic resistance gradient.
7. The gas exchange unit according to claim 1, characterised in that a gas-side humidifying and heating device is connected upstream of the hollow-fibre module.
8. The gas exchange unit according to claim 1, characterised in that the hollow-fibre module is drum-shaped.
9. The gas exchange unit according to claim 1, characterised in that in the hollow-fibre module a blood-impermeable layer is spirally arranged from an inside of a spiral to an outside of the spiral.
10. The gas exchange unit according to claim 1, characterised in that a blood flow can be guided from a peripheral region of the hollow-fibre module to a more central region of the hollow-fibre module or from the more central region to the peripheral region or diagonally between the peripheral region and the more central region of the hollow-fibre module.
11. The gas exchange unit according to claim 1, characterised in that said gas exchange unit has two or more hollow-fibre modules.
12. The gas exchange unit according to claim 11, characterised in that the hollow-fibre modules can be differently charged with gas.
13. The gas exchange unit according to claim 11, characterised in that said gas exchange unit has a second overflow device.
14. The gas exchange unit according to claim 11, characterised in that the hollow-fibre modules are connected with a valve.
15. The gas exchange unit according to claim 11, characterised in that the hollow-fibre modules configured to guide a gas flow can be connected in parallel or in series.
16. The gas exchange unit according to claim 11, characterised in that the hollow-fibre modules are drum-shaped and concentrically arranged one inside the other.
17. The gas exchange unit according to claim 11, characterised in that the hollow-fibre modules are formed as fibre mats and arranged one behind the other.
18. The gas exchange unit according to claim 17, characterised in that a fibre direction of a fibre mat is arranged at an angle to a fibre direction of a second fibre mat.
19. The gas exchange unit according to claim 18, characterised in that the angle is between 10 and 170.
20. The gas exchange unit according to claim 1, characterised in that a diameter to length ratio of the hollow-fibre module is less than 2.
21. The gas exchange unit according to claim 1, characterised in that it has an electric heating element.
22. The gas exchange unit according to claim 21, characterised in that it has a heating element provided on the gas side.
23. The gas exchange unit according to claim 1, characterised in that an embedding material forms a cylindrical closure towards the blood side.
24. A Kit with the gas exchange unit, according to claim 1, and a humidifying and heating device, characterised in that the humidifying and heating device is upstream of the hollow-fibre module in the gas flow.
25. The Gas exchange unit of claim 1, characterised in that the overflow device further comprises adjustable overflow channels.
26. The Gas exchange unit of claim 1, characterised in that the overlay is comprised at least one of foil or fleece.
Description
(1) The invention will be explained in more detail below with the aid of the drawings, in which
(2) FIG. 1 is a schematic representation of a gas exchange unit with two hollow-fibre modules connected in series;
(3) FIG. 2 is a schematic representation of a gas exchange unit with two hollow-fibre modules connected in parallel;
(4) FIG. 3 is a schematic representation of a gas exchange unit with two hollow-fibre modules, one of which can be switched on or off;
(5) FIG. 4 is a schematic representation of the operating principle of the heat exchange in a hollow-fibre module with a humidifying and heating device connected upstream on the gas side;
(6) FIG. 5 a is a schematic representation of a gas exchange unit with two hollow-fibre modules which are drum-shaped and arranged concentrically one inside the other;
(7) FIG. 5 b shows a cross-section from the gas exchange unit in FIG. 5a;
(8) FIG. 5 c shows a further cross-section of the gas exchange device from FIG. 5a, wherein both the air flow direction and the blood flow direction are schematically illustrated;
(9) FIG. 6 is a schematic representation of a gas exchange unit, wherein the hollow-fibre modules are designed as fibre mats;
(10) FIG. 7 a is a schematic representation of a gas exchange unit from FIG. 6, wherein the embedding material forms a cylindrical closure towards the blood side;
(11) FIG. 7 b is a schematic representation of a fibre arrangement from FIG. 6, wherein the fibre mats are alternately arranged crosswise at an angle of 120 and the embedding material is of cylindrical design towards the blood side;
(12) FIG. 8 a is a schematic representation of a plan view of a gas exchange unit in which the hollow-fibre modules are drum-shaped and arranged concentrically one inside the other, and an impermeable layer is used to guide the blood;
(13) FIG. 8 b is a schematic representation of a likewise drum-shaped hollow-fibre module arrangement, wherein a plurality of channels is formed by an impermeable layer;
(14) FIG. 9 a is a schematic representation of a gas exchange unit, wherein some of the gas exchanger fibres can be continuously switched on or off;
(15) FIG. 9 b is a schematic representation of a valve for connection and disconnection;
(16) FIG. 10 is a schematic representation of a gas exchange unit, wherein the diameter-to-length ratio of the hollow fibres>1 (is greater than 1);
(17) FIG. 11 is a schematic representation of a gas exchange unit with two hollow-fibre modules which are formed as fibre mats and arranged one behind the other;
(18) FIG. 12 is a schematic representation of a gas exchange unit formed as a fibre mat, with fibre regions arranged side by side;
(19) FIG. 13 is a schematic representation of a gas exchange unit with an overflow channel device;
(20) FIG. 14 is a schematic representation of the arrangement of the inlet to the overflow channel device in an arrangement according to FIG. 12 in side view in FIG. 14a) and in the section of a cross-section in FIG. 14b);
(21) FIG. 15 is a schematic representation of the arrangement of the inlet to the overflow channel device in an arrangement according to FIG. 11 in side view in FIG. 15a) and in the section of a cross-section in FIG. 15b);
(22) FIG. 16 is a schematic representation of a gas exchange unit with various overlays for increasing the pneumatic resistance;
(23) FIG. 17 is a schematic representation of a gas exchange unit with an overlay of differing thickness for increasing the pneumatic resistance in FIG. 17a), with a side view of the overlay in FIG. 17b) and a plan view of the overlay in FIG. 17c);
(24) FIG. 18 is a schematic representation of a gas exchange unit with adjustable overflow channels;
(25) FIG. 19 is a schematic representation of a gas exchange unit with an electric heating element;
(26) FIG. 20 is a schematic representation of a hollow fibre with information on the geometric definition.
(27) In a gas exchange unit 1 the blood is oxygenated and CO2 depleted from the blood. For this purpose, the blood flows through a hollow-fibre module. Gas flows through the interior of the hollow fibres (not illustrated). In FIG. 1 blood flows through two such hollow-fibre modules 2, 3 sequentially or in series. Here the blood, schematically represented by the arrow 4, first flows into gas exchange unit 2, through this and then gas exchange unit 3, until it is finally schematically represented leaving gas exchange unit 1 by the arrow 5. Once the gas, the flow of which is schematically represented by the arrows 6, 7, 8 and 9, has left the first gas exchanger, it is passed to the second one. As an option gas can also flow through both gas exchangers in parallel, as shown in FIG. 2. It is thus possible to adapt the gas exchange characteristics to suit requirements. This can be done in production during preassembly, prior to use or during use. Here the gas flow is schematically illustrated by the arrows 16, 17 and 18.
(28) As shown in FIG. 1, a counterflow of blood and gas direction is possible, with the blood first flowing through hollow-fibre module 2 and then hollow-fibre module 3, and the gas first flowing through hollow fibre module 3 and then hollow fibre module 2 (so-called countercurrent principle). The reverse order is also possible, in which case the blood first flows through hollow-fibre module 2 and then hollow-fibre module 3, and the gas likewise first flows through hollow-fibre module 2 and then hollow-fibre module 3 (so-called direct current principle). In particular it is possible to switch between the two circuitsin series or in parallelas required. As shown in FIG. 3, it is also possible to connect or disconnect one of the two hollow-fibre modules. For this purpose, it is connected with a valve 10.
(29) The mode of operation of a humidifying and heating device connected upstream on the gas side will be explained below with the aid of the section from a hollow-fibre module 21 as shown in FIG. 4. In this arrangement the heated gas and water vapour flows through the hollow-fibre module 21. The gas flow is represented symbolically by the arrows 22 and 23. The blood flow is represented symbolically by the arrows 24 and 25. The hollow fibres 27, 28, 29 and 30 are fixed in two layers 31 and 32 of embedding material. The gas is saturated with water vapour and has a temperature above blood temperature. In the hollow-fibre module 21 the gas gives off heat to the blood and a part of the water vapour condenses, also releasing the condensation energy to the blood. The condensate 26 is collected beneath the hollow-fibre module 21. The latter therefore functions both as a gas exchanger and heat exchanger.
(30) In the case of the gas exchange unit 41 two hollow-fibre modules 42, 43 are drum-shaped and concentrically arranged one inside the other. They are separated from each other by a separation layer 44, which can also be configured as a grid or mesh. The blood flows outwards from inside as symbolised by the arrows 45 and 46. It is also possible to guide the blood inwards from outside or diagonally outwards as symbolised by the arrows 45, 46, and 47. A possible gas flow path is again symbolised by the arrows 48, 49 and 50. Here first the outer hollow-fibre module 43 is charged with gas and then, in series connection, the inner hollow-fibre module 42. A parallel connection is also possible here. On the whole a gas exchange unit as formed in FIGS. 5 a, 5 b and 5 c is represented as a drum-shaped body.
(31) In a gas exchange unit 61 a stacked arrangement of hollow-fibre modules 62 and 63 may also be selected, as shown in FIG. 6. There the hollow-fibre modules 62, 63 are formed as fibre mats. These can each be arranged alternately crosswise to each other. The gas is symbolised by the arrows 66, 67 and 68, each passed from two sides through the hollow fibre. The blood flows through the gas exchange unit 61, as symbolised by the arrows 64, 65. Two or more of these units may be combined and charged with gas as shown in FIGS. 1 to 3.
(32) In FIG. 7a the fibre arrangement from FIG. 6 is designed so that the embedding material 79 around the fibre mats, for example 78, forms a cylindrical closure 80 towards the blood side. In the gas exchange unit 81 in FIG. 7b the fibre mats 82 and 83 are arranged crosswise at an angle of 120. Here the embedding material towards the blood side is also executed with a cylindrical closure 89. The outside, however, is not square compared to FIG. 7a, but hexagonal in design. The blood flow is symbolised by the arrows 84 and 85, with the gas inflow being symbolised by the arrows 86, 86 and 86 and the gas outflow by the arrows 87, 87 and 87. The individual hollow fibres 88 are visible.
(33) In a drum-shaped fibre arrangement 91, 101 as shown in FIG. 8 a and b, the blood is passed spirally from inside to outside by a blood-impermeable layer 92, 102, 103, 104. Here, as in arrangement 91, a channel is possible in the gas exchange unit 101, or even two or more channels, as in this instance three channels. Here the blood inflow is symbolised by the arrows 93, 105, 106, 107, the blood outflow by the arrows 94, 108, 109, 110.
(34) In the gas exchange unit 121 in FIG. 9a some of the gas exchange fibres such as 122 can continuously be switched on or off as required by an appropriate valve arrangement 123, and thus adapted to meet the need. Two perforated plates 132 and 133 movable relative to each other may be used as a valve 131, for example as shown in FIG. 9 b. The blood flow is symbolised by the arrows 124 and 125, the gas flow by the arrows 126, 127 and 128.
(35) As shown in FIG. 10, it is particularly advantageous if the gas exchange unit and the arrangement of the gas exchanger fibres are selected so that the internal diameter of the blood-carrying region is larger than the length thereof. The blood flow is again symbolised by the arrow 144, the gas flow by the arrow 145.
(36) The gas exchange unit 150 in FIG. 11 has two hollow-fibre modules, module A 151 and module B 152, which are formed as fibre mats and are arranged one behind the other. A longitudinal distribution of the gas exchange unit 150 is thus achieved.
(37) The gas exchange unit 160, which is formed as a fibre mat, also has two hollow-fibre regions, region A 161 and region B 162 as shown in FIG. 12, but which are arranged side by side. A transverse distribution of the gas exchange unit 160 is thus achieved.
(38) As shown in FIG. 13, a different charging of hollow-fibre module 170 can then be performed by overflow channel devices 171 and 172. The inflow of the gas takes place through the inlets 173, 174, each of which has a central chamber 175, 178 as well as two side chambers 176, 177 and 179, 180. The gas flows from the central chamber 175, 178 into the two side chambers 176, 177 and 179, 180. This results in an increased charging of sides 181 and 182 of the gas exchange unit 170 in the region of the central chamber 175, 178 as well as a weaker charging in the region of the two side chambers 176, 177 and 179, 180. A different flow through regions A and B is thereby achieved, as shown in FIG. 12. The gas again leaves the fibre bundle 187 at sides 183 and 184 and is led outside through the outlet 186.
(39) This arrangement according to FIG. 12 of the inlet 173 to the central chamber 175 with the side chambers 176, 177 in an arrangement can also be seen in side view in FIG. 14a) and in the section of a cross-section in FIG. 14b). Here it becomes clear how the central chamber 175 is connected to the side chambers 176, 177 by overflow channels such as 188 or 189.
(40) Also, in an arrangement according to FIG. 11, with a charging of the hollow-fibre modules 206, 207 by the overflow channel device 201 a different charging of the hollow-fibre modules A 206 and B 207 becomes possible. This can clearly be seen in FIG. 15 in an arrangement in side view in FIG. 15a) and in the section of a cross-section in FIG. 15b). The overflow channel device 201 has an inlet 202 which introduces the gas into a first chamber 203, whence it is passed into a second chamber 204 through overflow channels such as 205. This results in different charging of the gas exchange unit in the regions of the two chambers 203, 204 in the region of the different hollow-fibre modules A 206 and B 207.
(41) Another possibility for the different charging of the hollow fibre regions A and B in an assembly according to FIG. 12 is the application of an overlay on the fibre bundle 211, as shown in FIG. 16. Here different overlays, overlay A 212, overlay B 213 are applied on a side surface 215, thereby increasing the pneumatic resistance. The central region 214 remains foil-free. This also results in different charging of the three areas here (fibre region A in the region of the overlay A 212, fibre region B 213 in the region of the overlay B and fibre region C (here in addition to the assembly in FIG. 12) in the foil-free central region 214.
(42) A further possibility for the different charging of fibre regions A and B in an assembly according to FIG. 12 is the application of an overlay 222, 223 of differing thickness to increase the pneumatic resistance, as shown in FIG. 16. In FIG. 17a) in a side view of the overlay 222 in FIG. 17b) and a plan view of the overlay in FIG. 17c), each of the regions of differing thickness 225, 226 can be seen as thickness D1 and 224 as thickness D2. Overlay 222 is an air-permeable structure such as a fleece. A different gas permeability is achieved by the different thickness, resulting in a different flow resistance. A different gas permeability is also achieved by a different charging in the flow through the module. A continuous charging gradient can be achieved by a continuous configuration.
(43) One possibility for a structure for the variable charging of a fibre bundle 231 is implemented by adjustable overflow channels 232, 233, 234, 235, as shown in FIG. 18. Here a slide valve 238, 239 is fitted to the overflow channel device 236, 237, by means of which the openings 240, 241, 242, 243, 244, 245 of the overflow channel 236, 237 can be completely or partially covered. For this purpose, the openings 246, 247, 248, 249, 250, 251 of the slide valve 236, 238 are made to coincide completely or partially with those of the overflow channel 240, 241, 242, 243, 244, 245 by means of an adjusting device 252. Thus, the gas can either completely or partially enter directly into the chambers of the overflow channel or flow on into the chambers by way of the overflow channels 232, 233, 234, 235.
(44) In a gas exchange unit 261 with a fibre bundle 262, an electric heating element 264 may be arranged in the housing 263 to prevent condensation.
(45) For the individual hollow fibre, it is advantageous if, as shown schematically in FIG. 20, the fibre length (L1) relative to the internal fibre diameter (Di) is less than 500. In particular the length (L1) may be less than 80 mm, the internal fibre diameter (Di) may be in the order of 160 to 200 m.
