WO2000078231A1

WO2000078231A1 - Hemodialysis access system including subcutaneous port and catheter and associated cleaning apparatus

Info

Publication number: WO2000078231A1
Application number: PCT/US2000/016624
Authority: WO
Inventors: Paul J. Smith; Brian K. Estabrook; Frank R. Prosl; Klaus H. Sodemann
Original assignee: Biolink Corporation
Priority date: 1999-06-17
Filing date: 2000-06-16
Publication date: 2000-12-28
Also published as: AU5494100A

Abstract

This invention is a catheter brush assembly (40) for brush cleaning interior walls of a catheter (22), the assembly including a flexible elongated shaft (42) for movement lengthwise in the catheter, and a brush (44) mounted on the shaft proximate a distal end of the shaft adapted to engage to interior wall of the catheter to effect the brush cleaning. At least one of the distal ends of the shaft (49), a distal end of the brush (50) are rounded for non-traumatic contact with the wall of the catheter, and a wall of a blood vessel in which the catheter is disposed.

Description

HEMODIALYSIS ACCESS SYSTEM INCLUDING

SUBCUTANEOUS PORT AND CATHETER

AND ASSOCIATED CLEANING APPARATUS

Cross-Reference To Related Application

This patent application claims the benefit of pending prior U.S. Provisional Patent Application Serial No. 60/139,696, filed 06/17/99 by Paul J. Smith et al. for HEMODIALYSIS ACCESS SYSTEM INCLUDING SUBCUTANEOUS PORT AND CATHETER AND ASSOCIATED CLEANING APPARATUS (Attorney's Docket No. PROSL-10 PROV), which patent application is hereby incorporated herein by reference.

Field Of The Invention

The invention relates to hemodialysis access systems which comprise a subcutaneous port and catheter.

Background Of The Invention

Referring to Figs. 1 and 2, it will be seen that certain hemodialysis systems generally comprise a port 20 which is adapted to be positioned subcutaneously within the chest of the patient, and a catheter 22 which is connected to the port 20 and extends subcutaneously into the vascular system of the patient. The port 20 includes an output bay 24 and an input bay 26. The catheter 22 includes a pair of lumens 28: a suction lumen 28a for connecting the port's output bay 24 to the vascular system of the patient, and a return lumen 28b for connecting the port's input bay 26 to the vascular system of the patient. The port 20 also includes a valve (not shown) disposed intermediate the output bay 24 and the suction lumen 28a, and a valve (not shown) disposed intermediate the input bay 26 and the return lumen 28b, such that blood will be prevented from flowing out of the port's output and input bays 24, 26 at inappropriate times.

By way of example, but not limitation, hemodialysis access systems of the type comprising a subcutaneous port and catheter are described and illustrated in, or are otherwise referred to in, (1) pending U.S. Patent Application Serial No. 09/448,201, filed 11/23/99 by Frank R. Prosl et al. for APPARATUS AND METHOD FOR THE DIALYSIS OF BLOOD (Attorney's Docket No. PROSL-1 CON); (2) U.S. Patent Application Serial No. 09/251,572, filed 02/17/99 by Harold M. Martins et al. for APPARATUS AND METHOD FOR THE DIALYSIS OF BLOOD, METHOD FOR FABRICATING THE SAME, AND METHOD FOR THE DIALYSIS OF BLOOD (Attorney's Docket No. PROSL-3 CIP) ; and (3) U.S. Patent Application Serial No. 09/226,956, filed 01/08/99 by Brian K. Estabrook et al . for APPARATUS AND METHOD FOR SUBCUTANEOUS ACCESS TO THE VASCULAR SYSTEM OF A PATIENT (Attorney's Docket No. PROSL-4) .

The aforementioned U.S. Patent Applications Serial Nos. 09/448,201, 09/251,572 and 09/226,956 are hereby incorporated herein by reference.

When a patient is to undergo an active dialysis session, the subcutaneous port 20 is accessed by a pair of transcutaneous needles 30 (Figs. 3 and 5). More particularly, a first transcutaneous needle 30a is passed through the skin of the patient so that the first transcutaneous needle' s distal tip connects into the output bay 24 of the port 20, and a second transcutaneous needle 30b is passed through the skin of the patient so that the second transcutaneous needle's distal tip connects into the input bay 26 of the port 20. As the first transcutaneous needle 30a connects into the output bay 24 of the port 20, the first transcutaneous needle 30a opens the output bay's associated valve to fluid flow, and as the second transcutaneous needle 30b connects into the input bay 26 of the port 20, the second transcutaneous needle 30b opens the input bay's associated valve to fluid flow. Then the proximal ends of the two transcutaneous needles 30 are connected to the input and output bays of the dialysis machine (not shown) with appropriate tubing. Once this has been done, dialysis may be undertaken in a manner well known in the art, with "dirty" blood being withdrawn from the patient through the catheter's suction lumen 28a, and with "clean" blood being returned to the patient through the catheter's return lumen 28b, as illustrated in Fig. 2. At the conclusion of the dialysis session, the tubing is removed from the proximal ends of the two transcutaneous needles 30, and the two needles are withdrawn from the port 20. As' the two transcutaneous needles 30 are withdrawn from the port 20, the valves associated with the port's output and input bays 24, 26, automatically close, so as to prevent the patient from "bleeding out" through the port 20. By way of example, but not limitation, a transcutaneous needle is described and illustrated in the aforementioned U.S. Patent Application Serial No. 09/226,956, which application is incorporated herein by reference.

For convenience, Fig. 3 shows a transcutaneous needle assembly 36, such as is disclosed in the above-identified U.S. Patent Application Serial No. 09/226,956. As is explained in more detail in the above-identified U.S. Patent Application Serial No. 09/226,956, such transcutaneous needle assemblies preferably include an associated obturator 32 which is positioned within a bore 34 of the needle 30 while the needle is advanced through the skin of the patient so as to prevent the needle from coring tissue. Once the needle 30 has been successfully docked with the port 20, the obturator 32 is removed from the needle 30 and appropriate blood tubing is connected to the proximal end of the needle. To prevent escape of blood through the needle 30 after the obturator 32 is removed and before the appropriate blood tubing is connected, the needle assembly 36 is provided with a manually operated gate valve 38 which is operative to pinch closed a soft portion of the needle 30, as is described in the aforementioned U.S. Patent Application Serial No. 09/226,956.

It has been observed that surface contamination may build up on the catheter 22 between active dialysis sessions. This surface contamination may comprise blood products, catheter lock products, microbial material (e.g., bacterial and/or fungal), or even tissue and/or fibrin. This buildup of surface contamination can be particularly significant at the distal end of the catheter 22, which dwells within an active blood vessel, e.g., within the superior vena cava V (Figs. 1, 2 and 5) or the right atrium of the heart. The buildup of surface contamination may occur within the suction and/or return lumens 28a, 28b of the catheter 22, and/or around the outside of the distal end of the catheter. If left unaddressed, this buildup of contamination material can interfere with an active dialysis session.

Objects Of The Invention

Accordingly, a primary object of the present invention is to provide a device adapted to clear away any buildup of contamination material from the catheter, while the catheter is disposed within the patient.

Another object of the present invention is to provide a device adapted to free clots from the lumens of the catheter.

Still another object of the present invention is to provide a device adapted to restore lumens of a collapsed and/or kinked catheter to a fully open condition.

And another object of the present invention is to provide a novel method for cleaning a lumen in a subcutaneous hemodialysis port and catheter system.

Summary Of The Invention

With the above and other objects in view, a feature of the invention is the provision of a catheter brush assembly for brush-cleaning interior walls of a catheter, the brush assembly comprising a flexible elongated shaft for movement lengthwise in the catheter, and a brush mounted on the shaft proximate a distal end of the shaft, and adapted to engage the interior wall of the catheter to effect the brush-cleaning. At least one of the distal end of the shaft and a distal end of the brush is rounded for non-traumatic contact with the wall of the catheter and a wall of a vascular structure in which the catheter is disposed.

In accordance with a further feature of the invention, there is provided a catheter brush assembly for brush-cleaning interior walls of a catheter, the brush assembly comprising a flexible elongated shaft for movement lengthwise in the catheter, a brush mounted on the shaft proximate a distal end of the shaft and adapted to engage the interior wall of the catheter to effect the brush-cleaning, and a luer lock member mounted on the shaft proximally of the brush and adapted for engagement with a proximal portion of a needle assembly, the luer lock member having an aperture therein through which the shaft extends, and a seal member fixed to the luer lock member and having an opening therein through which the shaft extends, the shaft being movable through the aperture and the opening to move the brush in the needle assembly and the catheter, the seal member being of elastomeric material impinging upon the shaft to effect a seal around the shaft.

And in accordance with a further feature of the invention, there is provided a method for cleaning a lumen in a subcutaneous hemodialysis port and catheter system, wherein the method comprises the steps of: (1) introducing a brush, having a non-traumatic distal tip, into the lumen; and (2) brush-cleaning the lumen.

The above and other features of the invention, including various novel details of construction and combination of parts, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular devices embodying the invention are shown by way of illustration only and not as limitations of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention.

Brief Description Of The Drawings

Reference is made to the accompanying drawings in which are shown illustrative embodiments of the invention, from which its novel features and advantages will be apparent.

In the drawings:

Fig. 1 is a diagrammatic illustration of a known hemodialysis system in operative position;

Fig. 2 is an exploded diagrammatic illustration of the system of Fig. 1;

Fig. 3 is a sectional view of a known transcutaneous needle assembly used in conjunction with the system of Figs. 1 and 2;

Fig. 4 is a side elevational view of one form of apparatus for cleaning the catheter of the hemodialysis system of Figs. 1 and 2, the cleaning apparatus comprising a brush assembly illustrative of an embodiment of the invention;

Fig. 5 is similar to Fig. 1, but showing a brush of the type shown in Fig. 4 in conjunction with a transcutaneous needle of the type shown in Fig. 3 and the hemodialysis system of Fig. 1; Fig. 6 is similar to Fig. 4, but illustrative of an alternative embodiment of brush assembly;

Fig. 7-10 are elevational views of alternative embodiments of distal end portions of brush assemblies;

Fig. 11 is a diagrammatic illustration of a brush assembly shaft in part comprising a coiled wire structure and in part comprising a twisted wire structure;

Fig. 12 is a side elevational view of one embodiment of a distal end portion of a brush assembly;

Fig. 13 is a side elevational broken-away view of a catheter supported by an interior coil spring;

Fig. 14 is a side elevational view of a portion of an alternative embodiment of apparatus for cleaning the catheter portion of the system;

Fig. 15 is a side elevational view of an alternative embodiment of a brush assembly, including a sealing means; and

Fig. 16 is a proximal elevational view of a seal member of the assembly of Fig. 15.

Detailed Description Of The Invention

In accordance with the present invention, and looking now at Fig. 4, there is disclosed a novel catheter brush assembly 40. The catheter brush assembly 40 generally comprises an elongated shaft 42, and a plurality of bristles 41 constituting a brush 44 disposed adjacent to a distal end 46 of the shaft 42. The elongated shaft 42 is flexible, and the brush 44 is sized, so that after a transcutaneous needle 30 has been docked at the output (or input) bay 24, 26 of a port 20, and the obturator 32 is removed, the catheter brush assembly 40 can be passed through the needle 30, through the output (or input) bay 24, 26, through that bay's associated valve, and through that bay's associated catheter lumen 28a, 28b, until the brush portion 44 of the brush assembly 40 extends out a distal end 48 of the catheter 22 (Fig. 5) . In this way, the catheter brush 44 can be used to clean the lumen 28, and the surrounding portion of the distal end 48 of the catheter 22, of any buildup of contamination material. Thus, the patency of the lumen 28 can be restored and blood flow increased. The same catheter brush assembly 40 can then be used to clean the remaining lumen 28 of the catheter 22 or, preferably, another sterile catheter brush assembly can be used to clean the remaining catheter lumen.

It will be appreciated that, in addition to cleaning away the buildup of contamination material, the catheter brush assembly 40 can also be used to free clots from the lumens 28 of the catheter 40, and/or to restore the lumens of a collapsed and/or kinked catheter to a fully open condition.

Preferably, the distal end 50 of the catheter brush assembly 40 is rounded so that the distal end 50 of the brush assembly 40 will not damage the catheter wall, nor any surrounding vascular structure, as the brush 44 is moved through catheter 22 and then in and out of the distal end 48 of the catheter 22. Among other things, as shown in Figs. 1 and 5, the catheter brush assembly must pass through an acute angle bend B (located at the entrance to the jugular) without puncturing the catheter wall. In one preferred embodiment of the invention, the distal tip 50 of the catheter brush assembly 40 terminates in a soft rubber nose 52. It will be appreciated that the various elements of the catheter brush assembly 40 must be sized so as to be small enough to pass through the needle 30, port 20, and catheter 22, yet large enough so that the catheter brush 44 can clean catheter 22.

As seen in Figs. 4 and 5, the catheter brush 44 may have its bristles angled proximally so as to facilitate passage of the brush 44 distally through the needle 30, port 20 and catheter 22. Alternatively, the catheter brush 44 may have its bristles 41 extending radially, in much the same manner as a conventional bottle brush (Fig. 6) .

As noted above, in one preferred manner of use, the catheter brush assembly 40 is introduced into a transcutaneous needle 30 only after that needle has been docked with one of the bays 24, 26 of the port 20. However, if desired, the catheter brush assembly 40 can be loaded into a transcutaneous needle 30, in place of that needle's associated obturator 32, during insertion of the needle 30 into a port 20. In this situation, the catheter brush 44 will fill out the distal tip of the transcutaneous needle 30 during needle insertion so as to prevent coring during tissue penetration. Of course, the bristles 41 of the catheter brush 44 are safely stored within the body of the needle 30 during such needle insertion.

Figs. 7-10 illustrate some alternative brush constructions .

More particularly, in Fig. 7 there is shown a catheter brush assembly 40 in which the brush shaft 42 is formed by twisted wires 60, 62, and in which bristles 41 of the brush 44 are formed in a generally helical configuration. The shaft distal end 46 is in the form of a bulb 47 having a rounded distal surface 49.

Fig. 8 shows a catheter brush 44 having a "fantip" front tip configuration 66.

In some hemodialysis systems, the catheter is reinforced with internal structure, such as a coil or spring 54 (Fig. 13) . The rounded brush assembly distal end 50 traverses the coil segments, without the shaft 42 or brush 44 lodging thereagainst and impeding movement of a brush assembly in the catheter, or, puncturing the catheter wall between coil segments, which are relatively wide spread on the outside wall of the catheter bend B. Fig. 9 shows a catheter brush assembly 40 having a front tip 50 with a generally J-shaped configuration 68. With this construction, the J-shaped tip 68 curves back on itself as soon as it emerges from the catheter lumen 28 so as to provide a rounded, spring-like element ahead of the bristles 4,1. This rounded, spring-like element can yield if and when it encounters adjacent vascular structures, so as to avoid harming those vascular structures. The tip 46 of the shaft 42 is preferably formed with a non-traumatic configuration so as to avoid scoring the lumen wall during brush insertion and/or removal, and so as to avoid harming adjacent tissue during brush deployment and use.

Fig. 10 shows a catheter brush assembly 40 including a "buckle point" 70 distal to the bristles 41. With this construction, the brush's shaft 42 will "collapse" at the buckle point 70 if and when the leading tip 46 of the shaft 42 encounters tissue, so as to prevent damaging that tissue.

As shown in Fig. 11, the brush assembly 40 may be provided with a shaft 42 having a first portion 64 wherein the wire 60 is a center strand wire, and the wire 62 is coiled around the strand wire 60. The brush assembly 40 is further provided with a second portion 65 disposed proximally of the first portion 64 and wherein the wires 60, 62 are twisted together, as in Figs. 7-10, to fix the brush bristles 41 to the shaft to form the brush 44. Still referring the Fig. 11, the brush assembly 40 may be provided with a shaft third portion 67 disposed distally of the second portion 65 and wherein the wire 62 is again coiled around the strand wire 60. Thus, two wires 60, 62 may be utilized to form the shaft's first portion 64, its second portion 65 and its third portion 67. Alternatively, each of the three sections may be formed independently of one another, and then joined together in a separate operation. The coil type of shaft (i.e., first portion 64 and third portion 67) is generally more flexible than the twisted type of shaft (i.e., second portion 64) and facilitates the provision of the J-shaped shaft distal end (shown in Figs. 9 and 11) and the collapsible distal end (shown in Fig. 10) . At the same time, the twisted type of shaft' (i.e., second portion 64) is easy to make and provides a simple and effective way to attach bristles 41 to the shaft. In Fig. 12 there is shown a further alternative embodiment in which the shaft distal end 46 is provided with a rigid, annularly-shaped ring 56 which guides the brush assembly 40 through the catheter 22, overriding the coils 54, or other structural members, within the catheter.

It is also possible to clear away the buildup of contamination material from the lumens 28 of the catheter 22, and/or to free clots from the lumens of the catheter, and/or to restore the lumens of a collapsed and/or kinked catheter to a fully open condition, using a ram 80 (Fig. 14) instead of a brush 44. More particularly, such a ^'ram 80 is sized so as to make a sliding fit within the lumens 28 of the catheter 22, and preferably includes a rounded front tip 82 to minimize trauma to any tissue or catheter portion the tip 82 might encounter.

Referring to Fig. 15, it will be seen that in an alternative embodiment, the catheter brush assembly 40 includes a luer lock 90 mounted on the shaft 42. The luer lock 90 is complementary to a luer lock portion 92 of the transcutaneous needle assembly 36 of Fig. 3, and is engageable therewith to connect the catheter brush assembly 40 to the transcutaneous needle assembly 36 in preparation for effecting a brush-cleaning of the catheter 22. The shaft 42 passes through an aperture 94 in the brush assembly luer lock 90.

Mounted on the brush assembly luer lock 90 is one or more seal members 96 (Figs. 15 and 16), each of which may be in the form of a disc of elastomeric material having one or more slits 98 therein defining an opening 100 for the shaft 42. The shaft 42 is movable in the brush assembly luer lock aperture 94 and the seal member opening 100 to permit movement of the brush assembly 40 in the needle 30 and in the catheter 22. The walls of the seal member opening 100 are disposed tightly around the shaft 42, impinging upon the shaft 42 and effecting a seal around the shaft to prevent escape of blood around the shaft.

In general, it is anticipated that catheter brush assembly 40 will be used to clean a catheter lumen prior to the start of a dialysis session.

Accordingly, in one preferred method of use, a needle 30, with its associated obturator 32, is first passed through the skin of the patient and seated in one or the other of output bay 24 or input bay 26. This opens that bay's associated internal valve, but the presence of obturator 32 within needle 30 prevents the patient from "bleeding out" through needle 30. Then obturator 32 is removed and, as the obturator is removed, the needle's gate valve 38 is engaged so as to close off needle 30 to blood flow. Next, brush assembly 40 is connected to the rear of needle 30 by connecting the brush assembly' s luer lock 90 to the needle assembly's luer lock 92.' Then the needle assembly's gate valve 38 is released so as to open up needle 30 to blood flow. This allows blood to flow through needle 30, through the needle's luer lock 92, into the brush assembly' s luer lock 90, and up to seal member (s) 96 in brush assembly 40. However, blood cannot flow past seal member (s) 96 due to the close engagement of seal member (s) 96 with brush shaft 42.

Brush shaft 42 is then advanced so as to move the brush 44 through needle 22, through catheter 22, and out the distal end 48 of the catheter, whereupon brush- cleaning may be effected.

After brush-cleaning is completed, brush 44 is withdrawn from catheter 22 and needle 30. Then the needle's stop member 38 is activated so as to close off needle 30 to the flow of blood, and brush assembly 40 is dismounted from needle 30. The needle assembly is then connected to the dialysis machine via appropriate blood tubing.

The foregoing brush-cleaning process is then repeated for the other catheter lumen, preferably using a second catheter brush assembly.

Once both catheter lumens have been brush-cleaned, dialysis may be commenced, i.e., by activating needle stop members 38 so as to open the two needles to blood flow, and then operating the dialysis machine.

There is thus provided a device adapted to clear away buildup of contamination material from a catheter in place for hemodialysis. There is further provided a device adapted to free clots from the lumens of the catheter, and still further provided a device adapted to restore lumens of a collapsed or kinked catheter to an open condition.

It is to be understood that the present invention is by no means limited to the particular construction herein disclosed and/or shown in the drawings, but also comprises any modification or equivalent within the scope of the claims. For example, in the above description the cleaning apparatus is discussed in relation to a subcutaneous (i.e., port-based) hemodialysis system. While it is expected that the invention will find substantial utility in that environment, it will be apparent to those skilled in the art that the invention described herein also finds utility in percutaneous dialysis systems.

Claims

What Is Claimed Is:

1. A catheter brush assembly for brush-cleaning interior walls of a catheter, the brush assembly comprising: a flexible elongated shaft for movement lengthwise in the catheter; and a brush mounted on said shaft proximate a distal end of said shaft, and adapted to engage the interior wall of the catheter to effect the brush-cleaning; at least one of the distal end of said shaft and a distal end of said brush being rounded for non-traumatic contact with the wall of the catheter and a wall of a blood vessel in which the catheter is disposed.

2. A catheter brush assembly in accordance with claim 1 wherein the distal end of said shaft is a rigid portion of said shaft and is provided with a sufficient radius to guide said shaft through curved portions of the catheter and is sufficiently rounded to override structural supports in the catheter.

3. The catheter brush assembly in accordance with claim 2 wherein the structural supports in the catheter comprise coils of a coil spring and wherein the distal end of said shaft is adapted to override the coils of the coil spring.

4. The catheter brush assembly in accordance with claim 2 wherein the distal end of said shaft comprises an annular ring.

5. A catheter brush assembly in accordance with claim 4 wherein said brush passes through a needle before passing into the catheter, and the ring is provided with an outside diameter of about 85-95% of an interior diameter of the needle.

6. The catheter brush assembly in accordance with claim 5 wherein the outside diameter of the ring is about 50% of an interior diameter of the catheter.

7. The catheter brush assembly in accordance with claim 2 wherein the distal end of said shaft comprises a ball tip.

8. A catheter brush assembly in accordance with claim 7 wherein said brush passes through a needle before passing into the catheter, and the ball tip is provided with an outside diameter of about 85-95% of an interior diameter of the needle.

9. The catheter brush assembly in accordance with claim 8 wherein the outside diameter of the ball tip is about 50% of an interior diameter of the catheter.

10. The catheter brush assembly in accordance with claim 2 wherein the distal end of said shaft is provided with a rounded tip.

11. The catheter brush assembly in accordance with claim 10 wherein said rounded tip is of a material selected from a group of materials consisting of rubber, plastic, and metal.

12. The catheter brush assembly in accordance with claim 1 wherein said brush comprises bristles helically mounted on said shaft.

13. The catheter brush assembly in accordance with claim 1 wherein said brush comprises bristles mounted on said shaft and extending radially therefrom.

14. The catheter brush assembly in accordance with claim 1 wherein said brush comprises bristles mounted on said shaft and extending outwardly from said shaft and angled proximally.

15. The catheter brush assembly in accordance with claim 1 wherein the distal end of said brush comprises a hemi-spherically configured brush end portion, a diameter of the brush end portion being substantially equal to a diameter of a remainder of said brush.

16. The catheter brush assembly in accordance with claim 1 wherein said shaft includes a distal end portion extending distally of said brush and being biased such that upon emergence from a distal end of the catheter, the shaft distal end portion forms a J-shape proximally of said brush to provide the rounded distal end of said flexible shaft for the non-traumatic contact.

17. The catheter brush assembly in accordance with claim 1 wherein said shaft includes a distal end portion extending distally of said brush and being substantially collapsible such that upon contact with any of the walls the distal end, portion collapses to provide the non-traumatic contact.

18. The catheter brush assembly in accordance with claim 1 wherein said shaft comprises wires twisted together from said shaft and to fix said brush to said shaft .

19. The catheter brush assembly in accordance with claim 18 wherein said wires comprise first and second wires.

20. The catheter brush assembly in accordance with claim 1 wherein said shaft comprises a first portion comprising a generally center strand wire and a second wire coiled around the center strand wire, and a second portion disposed distally of the first portion and wherein two strands of wire are twisted together to fix said brush to said shaft.

21. The catheter brush assembly in accordance with claim 20 wherein said shaft comprises a third portion disposed distally of the second portion, said third portion comprising a generally center strand wire and another wire coiled around the center strand wire.

22. The catheter brush assembly in accordance with claim 18 wherein said shaft is sufficiently rigid to be pushed through the catheter and sufficiently flexible to pass through an acute angle bend in the catheter.

23. The catheter brush assembly in accordance with claim 1 wherein said shaft comprises a wire coil.

24. The catheter brush assembly in accordance with claim 23 wherein said shaft further comprises a center strand extending centrally through the coil, and said shaft includes a portion in which the strand and the coil wires are twisted together to fix said brush to said shaft.

25. The catheter brush assembly in accordance with claim 1, the assembly further comprising: a luer lock member mounted on said shaft proximally of said brush and adapted for engagement with a proximal portion of a needle assembly, said luer lock having an aperture therein through which said shaft extends; a seal member fixed to said luer lock member and having an opening therein through which said shaft extends; said shaft being movable through the aperture and the opening to move said brush in the needle and the catheter; the seal member being of elastomeric material impinging upon said shaft to effect a seal around said shaft.

26. The catheter brush assembly in accordance with claim 25 wherein the seal member opening comprises a slit.

27. The catheter brush assembly in accordance with claim 25 wherein the seal member opening comprises intersecting slits.

28. A catheter brush assembly for brush-cleaning interior walls of a catheter, the brush assembly comprising: a flexible elongated shaft for movement lengthwise in the catheter; a brush mounted on said shaft proximate a distal end of said shaft, and adapted to engage the interior wall of the catheter to effect the brush-cleaning; and a luer lock member mounted on said shaft proximally of said brush and adapted for engagement with a proximal portion of a needle assembly, said luer lock having an aperture therein, through which said shaft extends; and a seal member fixed to said luer lock member and having an opening therein through which said shaft extends; said shaft being movable through the aperture and the opening to move said brush in the needle assembly and the catheter; the seal member being of elastomeric material impinging upon said shaft to effect a seal around said shaft.

29. The catheter brush assembly in accordance with claim 28 wherein the seal member opening comprises a slit.

30. The catheter brush assembly in accordance with claim 29 wherein the seal member opening comprises intersecting slits.

31. A hemodialysis catheter cleaning assembly for cleaning interior walls of a hemodialysis catheter, the assembly comprising a flexible elongated shaft for movement lengthwise in the catheter, a distal end of said shaft being rounded for non-traumatic contact with the wall of the catheter and a wall of a blood vessel in which the catheter is disposed.

32. A catheter cleaning assembly in accordance with claim 31 wherein the distal end of said shaft is a rigid portion of said shaft and is provided with a sufficient radius to guide said shaft through curved portions of the catheter and is sufficiently rounded to override structural supports in the catheter.

33. The catheter cleaning assembly in accordance with claim 31 wherein said rounded shaft distal end is of a material selected from a group of materials consisting of rubber, plastic, and metal.

34. A catheter brush assembly in accordance with claim 2 wherein said brush passes through a needle before passing into the catheter, and the rigid portion is provided with an outside diameter of about 85-95% of an interior diameter of the needle.

35. A method for cleaning a lumen in a subcutaneous hemodialysis port and catheter system, wherein said method comprises the steps of:

(1) introducing a brush, having a non-traumatic distal tip, into the lumen; and

(2) brush-cleaning the lumen.

36. A method for cleaning a lumen in a subcutaneous hemodialysis port and catheter system, wherein said method comprises the steps of:

(1) passing a needle and obturator assembly through the skin of the patient and docking the needle and obturator assembly with a bay of the port;

(2) removing the obturator from the needle;

(3) inserting a brush, having a non-traumatic distal tip, through the needle, through the port and through the catheter; and

(4) brush-cleaning the lumen.

37. A method for cleaning a lumen in a subcutaneous hemodialysis port and catheter system, wherein said method comprises the steps of: (1) inserting a brush, having a non-traumatic distal tip, into a needle, and passing the needle through the skin of the patient' and docking the needle with a bay of the port;

(2) passing the brush through the port and through the catheter; and

(3) brush-cleaning the lumen.