APPARATUS FOR EXCHANGING MATERIAL BETWEEN BLOOD AND A GAS/GAS MIXTURE

Abstract

The invention relates to an apparatus for exchanging material between blood and a gas/gas mixture, comprising a chamber (1) through which blood can flow and in which a plurality of material-permeable fiber tubes is provided, the gas/gas mixture being flowable through the fiber tubes, blood being flowable around the fiber tubes. At least one deformable element (9) is provided in the chamber (1) in addition to the fiber tubes, through which the gas/gas mixture can flow, this deformable element being deformable and restorable, in particular compressible out of a relaxed shape and restorable to a relaxed shape by pressure fluctuations acting on the at least one element (9) externally, in particular pressure fluctuations transmitted by the blood in the chamber (1).

Claims

1. An apparatus for exchanging material between blood and a gas/gas mixture, the apparatus comprising: a chamber through which blood can flow; a plurality of elongated material-permeable fiber tubes extending along an axis in the tube; means for flowing the gas/gas mixture through the fiber tubes; and the blood around the fiber tubes, at least one deformable element around which the blood can flow in the chamber, the deformable element being deformable and restorable by pressure fluctuations acting externally on the at least one element from the blood in the chamber for providing a windkessel effect to which end the at least one element is compressible from a relaxed shape, during a n systolic increase in blood pressure and during a diastolic decrease of the blood pressure is restorable to the relaxed shape.

2. The apparatus according to claim 1, wherein the at least one deformable element is passive without any artificial pressure control and is exclusively provided for providing the windkessel effect.

3. The apparatus according to claim 1, wherein the at least one deformable element is a tubular hollow body that is filled with a gas that does not flow through the hollow body, and the at least one hollow body is not open on one of its ends.

4. The apparatus according to claim 3, wherein in the chamber, a multiplicity of the tubular bodies are impermeable and made of elastic silicon fibers, the fibrous hollow bodies extending parallel to the axis and being surrounded by the fiber tubes while making contact with this fiber tubes.

5. The apparatus according to claim 3, wherein the at least one deformable hollow body and the material-permeable fiber tubes open into a gas inlet or a gas outlet to which the gas/gas mixture that participates in the material exchange is applied.

6. The apparatus according to claim 1, wherein the at least one deformable hollow body opens into a separate space that can be filled with a gas that does not participate in the material exchange, the space being provided axially downstream in the chamber of the gas outlet.

7. The apparatus according to claim 6, wherein the gas pressure in the separate space (10), is variably statically adjustable.

8. The apparatus according to claim 6, wherein the separate space is provided on one of the two axial ends of the apparatus opposite an inlet or outlet for blood.

9. The apparatus according to claim 8, wherein on one of the two axial ends of the apparatus, a connection for a blood inlet and a blood outlet is provided, one of the connections opening into an annular circumferential compartment that surrounds the chamber, and a passage opens into the other connection and is surrounded by the material-permeable fiber tubes and a plurality of particularly fibrous hollow bodies, and is coaxial to the central axis of the apparatus, and has at least one opening near the other axial end, through which particularly blood can pass from the chamber into the passage.

10. Use of elastically deformable fibrous gas-filled hollow bodies in a chamber through which blood can flow, in an apparatus for exchanging material between blood and a gas/gas mixture, comprising such a chamber, in which a plurality of material-permeable hollow bodies are arranged, wherein the gas/gas mixture can flow through the fiber tubes, and blood can flow around the fiber tubes as well as the fibrous hollow bodies for providing a windkessel effect by the compressibility of the fibrous hollow bodies during an increase of the blood pressure, particularly during the systole, and the expandability of the hollow bodies during a decrease of the blood pressure, particularly during the diastole.

11. An apparatus for exchanging material between blood and a gas/gas mixture, the apparatus comprising: a housing defining a chamber extending along an axis and having axially opposite ends; means for feeding blood into the chamber at one of the ends and withdrawing the fed-in blood from the chamber at the other of the ends; a plurality of gas-permeable tubes extending axially in the chamber between the ends; means for passing the gas/gas mixture through the tubes, whereby material change between the blood and the mixture can take place; and a gas-impermeable hollow body in the chamber filled with a gas and compressible by pressure of the blood passing through the chamber.

12. The apparatus defined in claim 11, wherein the gas filling the hollow body is the gas/gas mixture.

13. The apparatus defined in claim 11, wherein there are a plurality of hollow bodies extending axially in the chamber with the tubes.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0045] Preferred embodiments of the invention shall be described in more detail using the drawings described below and in which:

[0046] FIG. 1 is a schematic side view of the material-exchange apparatus of the invention;

[0047] FIG. 2 is a view like FIG. 1 of another apparatus according to the invention; and

[0048] FIG. 3 is another view like FIG. 1 of yet another apparatus according to the invention.

SPECIFIC DESCRIPTION OF THE INVENTION

[0049] FIG. 1 shows an embodiment that has a longitudinal extension direction with reference to FIG. 1 from top to bottom, i.e. in the paper plane, whereas perpendicular to the paper plane, the cross-section shape of the apparatus is, for example round. Any other cross-section shape is also possible.

[0050] The apparatus comprises a housing that defines a chamber 1 into which blood can flow from a blood inlet 2 to a blood outlet 3. The blood inlet is designed such that blood can flow axially into the inlet; however, due to an annular compartment 4 that surrounds the formed chamber 1 at one axial end, it is diverted to the outer periphery of the chamber 1 at this axial end in order to subsequently flow from this annular compartment 4 radially inward into the chamber 1.

[0051] In terms of the longitudinal extension direction and the central axis 5 of the chamber 1, a passage 6 is formed coaxially in the chamber 1 in the apparatus or the chamber formed by the housing, with the upper end of this passage 6 opening into the blood outlet 3, and this passage 6 having an end located in the chamber 1 that near the other axial end has at least one opening 7, in which the blood can pass from the chamber 1 into the passage 6. The blood in its flow path thus flows from the upper end 1a of the housing radially on its way from outside toward the inside in the direction of the lower end 1b of the apparatus in order to subsequently flow back through the passage 6 to the blood outlet 3.

[0052] On the two axial ends 1a and 1b of the housing, inlet and outlets 8a and 8b are provided for a gas participating in the material exchange, and the gas provided for the material exchange is supplied to the inlet 8a. The cross-sections of the gas inlet 8a and of the gas outlet 8b are each such that the entire chamber cross-section is covered perpendicularly to the axial extension.

[0053] The gas flows from the inlet 8a through a multiplicity of gas-permeable fiber tubes that open into the gas inlet 8a and are used for the material exchange, in the direction of the outlet 8b, in which the fiber tubes also open into at the other end in order to reach the gas outlet from there.

[0054] For clarity of view, FIG. 1 does not show the multiplicity of the permeable fiber tubes that participate in the material exchange. However, these fiber tubes each extend parallel to the axial direction or the central axis 5 between the inlet 8a and the outlet 8b and each open into this areas, and so the inner volumes of the fiber tubes participating in the material exchange communicate with the gas outlet and the gas inlet.

[0055] According to the invention, that in one extension parallel to the central axis 5 or the multiplicity of the fiber tubes participating in the material exchange, additional fibrous or tubular hollow bodies 9 are inserted that also surround the passage 6 in a parallel arrangement. The internal chamber volume, in addition to the blood, is thus filled by both the fiber tubes participating in the material exchange and the fibrous hollow bodies that are particularly not participating in the material exchange and that, according to the invention, have deformable, particularly elastic outer walls and are therefore made, for example, of silicon fiber tubes or hollow silicon tubes or tubes or fibers made of other elastic materials, or of other elastic materials, particularly with a tensile modulus smaller than 0.05 kN/mm.sup.2.

[0056] In FIG. 1, it can be seen that each of the deformable hollow bodies 9 has an open upper end that opens into the gas inlet 8b, while the lower end at the gas outlet 8b is closed. Each hollow body 9 preferably extends through the entire chamber 1. As a result, the gas that participates in the material exchange fills the interior of the deformable hollow bodies 9 but cannot flow through the hollow bodies.

[0057] The deformable hollow bodies 9 together form an overall compressible volume that decreases proportionately as blood pressure increases (for example during the natural systole or a pulsatile blood pump), and expands back to its relaxed original shape as blood pressure decreases (for example during the natural diastole or a pulsatile blood pump). This volume can thus compensate for the blood pressure fluctuations caused by the heartbeat and furthermore, due to the deformability, significantly contribute passively to the pump effect of the heart because blood is displaced from the chamber during relaxation.

[0058] The multiplicity of the deformable hollow bodies 9 can thus contribute to generating a windkessel effect that otherwise is achieved by the flexibility of vascular tissue, particularly the pulmonary artery, and significantly relieves pressure on the heart and thus assists pump action.

[0059] Particularly in case of a complete substitution of a lung function by such an apparatus according to the invention, the apparatus can thus contribute to a relief of the heart in a passive manner, i.e. without having to actively artificially control the deformable fiber tubes in any way.

[0060] FIG. 2 shows a variation of FIG. 1, in which the blood inlet 2 and the blood outlet 3 are merely functionally interchanged, and, however, the hollow bodies 9 that provide the windkessel effect, are permanently upwardly closed, particularly also not open or openable at the gas inlet and open at into the gas outlet 8b. The fiber tubes responsible for the gas exchange are again shown as lines between the hollow bodies 9.

[0061] FIG. 3 shows a different possible embodiment, in which the apparatus according to the invention has basically the same design, i.e. the housing encompasses a chamber 1, through which blood flows in the same manner as is realized in FIG. 1 with regard to the flow control. The corresponding design features apply as well.

[0062] However, the design is such that the individual deformable hollow bodies 9 that are once again designed so as to be fibrous or tubular and aligned parallel to the material-permeable fiber tubes and parallel to the central axis 5, each with a lower end opening into a common space 10 that is separate both from the chamber and the surroundings, and so the overall available compressible volume is constituted by the sum of the individual volumes of each individual deformable hollow body 9 as well as the volume of the space 10.

[0063] Here, it is possible to apply a specifically desired pressure to the space 10 in order to be able to adjust the rigidity or elasticity and compressibility of the overall volume.

[0064] The overall arrangement of the overall generated volume and the multiplicity of deformable hollow bodies 9 that are made from a preferably elastic material, thus forms a type of spring element whose the spring constant can be individually changed by the pressure. It is thus possible to application-specifically change the deformation and the volume change of the individual hollow bodies 9 at the existing blood pressure fluctuations caused by the heartbeat.

[0065] For example, a connection can also be provided at the separate space 10 for supplying or draining gas in order to change the internal pressure but this is not shown in FIG. 3.

[0066] However, instead of arranging only one single space 10 at the lower end of the apparatus, according to the invention two or more separate spaces with a specific number of the overall available hollow bodies 9 can be provided opening into each of these spaces. As a result, the elastic reaction to blood pressure changes can be adjusted differently for different thus-formed groups of hollow bodies 9.

[0067] Both embodiments allow, for example, an use inside the body of the apparatus, particularly to completely replace a lung function, or to be operated parallel to the natural lung, where the heart activity can be relieved significantly and particularly in a variably adjustable manner due to the internal deformability of the multiplicity of the hollow bodies 9. Therefore, the heart itself and particularly the right ventricle can be used as pump for operating the apparatus.

[0068] Toward the outer surroundings, the space 10 can have at least one flexible wall, for example made of an elastomer (for example, a silicon) or alternatively can be designed so as to be rigid.

[0069] As shown in FIGS. 1a and 2, blood inlet and blood outlet can be functionally interchanged, particularly without changing the design.