Filter member and oxygenator using same

Abstract

A filter member used in an oxygenator is constructed to provide improved contact with a hollow fiber membrane bundle and to capture bubbles contained in blood. The filter member possesses elasticity at least in the circumferential direction to allow the inner circumference of the filter member to be increased from a natural non-expanded state prior to placement on the hollow fiber membrane bundle to an expanded state in which the inner circumference of the filter member is increased when placed on the hollow fiber membrane bundle. The filter member is constructed to satisfy the condition 0.5≦L2/L1<1, wherein L1 represents the outer circumference of the hollow fiber membrane bundle and L2 represents the inner circumference of the filter member in the natural non-expanded state.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

FIG. 1 is a perspective exploded view of an embodiment of a filter member disclosed herein.

FIG. 2 is a plan view, partly broken away, of an embodiment of an oxygenator disclosed herein.

FIG. 3 is a left side view of the oxygenator shown in FIG. 2 as viewed in a direction of arrow III.

FIG. 4 is a cross-sectional view of the oxygenator taken along the section line IV-IV in FIG. 3.

FIG. 5 is a cross-sectional view of the oxygenator taken along the section line V-V in FIG. 2.

FIG. 6 is an enlarged cross-sectional view of a portion of the oxygenator showing the manner of fixing a hollow fiber membrane and filter member to a partitioning wall.

FIG. 7 is a plan view, partly broken away, showing the manner in which the hollow fiber membranes are arranged in the disclosed embodiment.

FIG. 8 is a cross-sectional view similar to FIG. 5 illustrating another embodiment of the oxygenator that includes a different housing.

FIG. 9 is a perspective view of the housing used in the oxygenator shown in FIG. 8.

Claims

1. An oxygenator comprising: a housing;a hollow fiber membrane bundle comprised of a plurality of gas-transmissive hollow fiber membranes each possessing a lumen, the hollow fiber membrane bundle comprising an outer peripheral surface defining an outer circumference of the hollow fiber membrane bundle;a gas inlet port communicating with the lumens of the hollow fiber membranes to introduce an oxygen-containing gas into the lumens;a gas outlet port communicating with the lumens of the hollow fiber membranes;a blood inlet port communicating with a blood flow path that is exterior of the hollow fiber membranes in the housing;a blood outlet port communicating with the blood flow path;a filter member adapted to be positioned in the housing in surrounding relation to the outer peripheral surface of the hollow fiber membrane bundle;the filter member possessing circumferential elasticity allowing an inner circumference of the filter member to be increased from a natural non-expanded state prior to placement on the hollow fiber membrane bundle to an expanded state in which the inner circumference of the filter member is increased when placed on the hollow fiber membrane bundle; andthe inner circumference of the filter member in the natural non-expanded state being less than the outer circumference of the hollow fiber membrane bundle.

2. The oxygenator according to claim 1, wherein the outer circumference of the hollow fiber membrane bundle is represented by L1 and the inner circumference of the filter member in the natural non-expanded state is represented by L2, and wherein 0.5≦L2/L1<1.

3. The oxygenator according to claim 1, wherein the filter member is made of a material which captures bubbles in the blood passing through the filter member.

4. The oxygenator according to claim 1, wherein the filter member is a mesh.

5. The oxygenator according to claim 1, wherein the filter member is a mesh having a mesh size not greater than 80 μm.

6. The oxygenator according to claim 1, wherein the filter member is hydrophilic.

7. The oxygenator according to claim 1, wherein the filter member is a sheet member rolled into an annular form with opposite edges of the sheet member being joined together along a joint.

8. The oxygenator according to claim 7, wherein the joint extends in a direction inclined relative to a widthwise direction of the filter member so that the joint extends around a portion of the circumference of the filter member.

9. An oxygenator comprising: a housing;a hollow fiber membrane bundle positioned in the housing and comprised of a plurality of integrated hollow fiber membranes that are transmissive to gas and that each include a lumen, the hollow fiber membrane bundle possessing an outer peripheral surface;a gas inlet and a gas outlet respectively positioned upstream and downstream of the lumens of the hollow fiber membranes;a blood inlet and a blood outlet respectively positioned upstream and downstream of a blood passage that is exterior of the hollow fiber membranes; anda cylindrically shaped filter member arranged in close contact with the outer peripheral surface of the hollow fiber membrane bundle, the filter member possessing a longitudinal axis and being comprised of a thread;wherein the filter member possesses circumferential elasticity allowing the filter member to be circumferentially expanded when placed on the hollow fiber membrane bundle; andthe thread comprising the filter member being arranged in a direction other than parallel to a plane that is perpendicular to a longitudinal axis of the filter member.

10. The oxygenator according to claim 9, wherein the filter member is a mesh.

11. The oxygenator according to claim 9, wherein the filter member is a mesh having a mesh size not greater than 80 μm.

12. The oxygenator according to claim 9, wherein the filter member is hydrophilic.

13. A filter arrangement configured to be positioned in a housing of an oxygenator, comprising: a cylindrically shaped filter member in combination with a hollow fiber membrane bundle comprised of a plurality of integrated hollow fiber membranes that are transmissive to gas;the filter member being configured to be arranged over an outer periphery of the hollow fiber membrane bundle to closely contact the outer periphery of the hollow fiber membrane bundle;the filter member possessing circumferential elasticity allowing an inner circumference of the filter member to be increased from a natural non-expanded state prior to placement on the hollow fiber membrane bundle to an expanded state in which the inner circumference of the filter member is increased when placed on the hollow fiber membrane bundle; andthe outer circumference of the hollow fiber membrane bundle being represented by L1 and the inner circumference of the filter member in the natural non-expanded state being represented by L2, and wherein 0.5≦L2/L1<1.

14. The filter member according to claim 13, wherein the filter member is configured to capture bubbles mingled in blood.

15. The filter member according to claim 13, wherein the filter member is a mesh.

16. The filter member according to claim 13, wherein the filter member is comprised of a sheet formed by crossing a warp thread and a weft thread with each other.

17. The filter member according to claim 16, wherein the warp threads or the weft threads are arranged in a direction inclined at an angle other than zero degrees relative to a plane that is perpendicular to a longitudinal axis of the filter member.

18. The filter member according to claim 13, wherein the filter member is a mesh possessing a mesh size not greater than 80 μm.

19. The filter member according to claim 13, wherein the filter member is hydrophilic.

20. The filter member according to claim 13, wherein the filter member is comprised of a sheet rolled into an annular form with opposite edges of the sheet joined together at a joint.

21. The filter member according to claim 20, wherein the joint is a joint produced by fusion or bonding.

22. The filter member according to claim 20, wherein the joint extends in a direction inclined relative to a widthwise direction of the filter member.

23. The filter member according to claim 13, wherein the hollow fiber membrane bundle possesses an overall circular cylindrical form.

24. An oxygenator comprising: a housing;a hollow fiber membrane bundle comprised of a plurality of integrated gas-transmissive hollow fiber membranes each possessing a lumen, the hollow fiber membrane bundle comprising an outer peripheral surface defining an outer circumference of the hollow fiber membrane bundle;a gas inlet port communicating with the lumens of the hollow fiber membranes at an upstream side of the lumens to permit an oxygen-containing gas to be introduced into the lumens;a gas outlet port communicating with the lumens of the hollow fiber membranes at a downstream side of the lumens;a blood inlet port communicating with a blood flow path that is exterior of the hollow fiber membranes in the housing;a blood outlet port communicating with the blood flow path;a filter member positioned in the housing in surrounding relation to the outer peripheral surface of the hollow fiber membrane bundle, the filter member possessing a longitudinal axis;the filter member being comprised of a plurality of intersecting threads forming a mesh;the plurality of threads being arranged to form an angle other than zero degrees with a plane perpendicular to the longitudinal axis of the filter member so that the filter member possesses circumferential elasticity allowing an inner circumference of the filter member to be increased from a natural non-expanded state prior to placement on the hollow fiber membrane bundle to an expanded state in which the inner circumference of the filter member is increased when placed on the hollow fiber membrane bundle; andthe outer circumference L1 of the fiber membrane bundle being dimensioned relative to the inner circumference L2 of the filter member in the natural non-expanded state so that L2/L1<1.