Oxygenator comprising a hollow-fiber film bundle

Abstract

An oxygenator comprising a hollow-fibre film bundle is surrounded at least in certain areas by a bubble-retaining filter. In order to ensure an optimal function of the hollow-fibre film bundle and the bubble-retaining filter, it is proposed that a gas-permeable retaining structure is arranged between hollow-fibre film bundle and bubble-retaining filter.

Claims

1. An oxygenator comprising a hollow-fiber film bundle, which is surrounded by a bubble-retaining filter at least in certain areas, wherein a gas-permeable retaining structure is disposed between the hollow-fiber film bundle and the bubble-retaining filter, and wherein the retaining structure is flexible and exerts a compressive pressure on the hollow-fiber film bundle such that a channel is formed radially outside of the retaining structure.

2. The oxygenator according to claim 1, wherein the gas-permeable retaining structure rests against the hollow-fiber film bundle.

3. The oxygenator according to claim 1, wherein the retaining structure surrounds the outer surface of the hollow-fiber film bundle.

4. The oxygenator according to claim 1, wherein the retaining structure is a network.

5. The oxygenator according to claim 1, wherein the retaining structure has a pore width of more than 100 micrometers.

6. The oxygenator according to claim 1, wherein the bubble-retaining filter has a pore width of no more than 50 micrometers.

7. The oxygenator according to claim 1, wherein the bubble-retaining filter and gas-permeable retaining structure are each made from a woven fabric.

8. The oxygenator according to claim 1, wherein the bubble-retaining filter and gas-permeable retaining structure are made from the same material.

9. The oxygenator according to claim 1, wherein the gas-permeable retaining structure is made from a polymer.

10. The oxygenator according to claim 1, wherein the gas-permeable retaining structure has a conical shape which corresponds to the shape of an inner wall of the oxygenator located radially outside the hollow-fiber film bundle.

11. The oxygenator according to claim 1, wherein the gas-permeable retaining structure positively presses the hollow-fiber film bundle against an inner wall of a housing of the oxygenator.

Description

(1) In the figures

(2) FIG. 1 shows a perspective view of an oxygenator,

(3) FIG. 2 shows a plan view of the oxygenator,

(4) FIG. 3 shows a section through the oxygenator shown in FIG. 1 and

(5) FIG. 4 shows schematically the cooperation of bubble-retaining filter and gas-permeable retaining structure.

(6) The oxygenator 1 shown in FIG. 1 has a blood inlet 2 and a blood outlet 3. A water inlet 4 and a water outlet 5 are provided as further connections for temperature-control of the blood. Gas is supplied to the oxygenator at the inlet 6 and removed at the outlet 7.

(7) The oxygenator housing 8 has a cover 9 via which the blood is supplied. If air bubbles should be located in the supplied blood, these are separated from the liquid by a forced blood vortex in the inlet region 10 and removed through the gas outlet 11.

(8) The blood flows initially in the radially inner region along a hollow-fibre film bundle 12 in which water is guided for temperature control of the blood and then through a radially outer region in which a hollow-fibre membrane bundle 13 is arranged in order to achieve an exchange of gas between blood and gas flow through gas guided into the hollow fibres. Finally the blood leaves the oxygenator through the outlet 3.

(9) The oxygenator housing has a radially inner wall 14, a middle wall 15 and an outer wall 16. The lower region of the oxygenator is formed by a base 17 in which water inlet and outlet 4, 5 and gas outlet 7 are located.

(10) The hollow-fibre membrane bundles 12 and 13 are embedded in adhesive for sealing at the points 18 to 22.

(11) FIG. 4 shows very schematically and only as an example an outer housing wall 30 with a blood outlet region 31 and an inner housing wall 32 located radially further inwards. Outer and inner housing wall are arranged slightly conically and concentrically to one another so that a space 33 lies between the housing walls which is radially delimited by walls arranged parallel to one another. Located in the lower region of the inner wall 32 is an inlet 34 which allows blood to flow from the inlet 34 through the space 33 to the outlet 31.

(12) A hollow-fibre membrane bundle 36 is provided in the space 33 resting on the outer side 35 of the inner wall 32. This hollow-fibre membrane bundle 36 is pressed by a gas-permeable retaining structure 37 radially inwards onto the inner wall 32. The gas-permeable retaining structure thus acts as a hollow-fibre compression layer.

(13) On the other side of the space 33 a bubble-retaining filter 39 rests against the inner side 38 of the outer wall 30 which must have flow passing through it at one point so that the blood can pass from the blood inlet 34 to the blood outlet 31.

(14) In an oxygenator 1 as shown in FIG. 1, the opposite ends of the bubble-retaining filter 39 and the gas-permeable retaining structure 37 are embedded in adhesive at the points 18 to 22 like the hollow-fibre membrane bundle 12 and 13 and then cut off at the top and bottom side together with the overhanging adhesive.

(15) In the installed state the gas-permeable retaining structure 37 is under tension in such a manner that it presses the hollow-fibre film bundle 36 against the inner wall 32. In so doing, the openings in the network-like retaining structure are held open by the tension so that a pore width is formed with a mean pore diameter of at least 100 micrometers.

(16) The bubble-retaining filter 39 is located at a distance from the retaining structure 37, its pore width being designed so that the mean diameter of the pores is not more than 50 micrometers.