GB2569008A

GB2569008A - Multi-lumen catheters and methods of manufacture

Info

Publication number: GB2569008A
Application number: GB1816123.2A
Authority: GB
Inventors: James Field Stephen; Neal King William; Daniel Perkins Jamie; Pourrasoul Milad
Original assignee: Smiths Medical International Ltd
Current assignee: Smiths Medical International Ltd
Priority date: 2017-10-20
Filing date: 2018-10-03
Publication date: 2019-06-05
Also published as: GB201717235D0

Abstract

A multi-lumen catheter 1 or the like is extruded with two or more tubes 13 and 14 continuously and interruptedly between a patient end 15 and a machine end 16 of the catheter, avoiding the need for a joining a separate manifold for machine end extension lines and thus reducing risks of leakage and damage of fluids. The tubes 13,14 are retained together along their length either by a separable or rupturable low peel strength join 42 that allows the machine ends 27 and 28 of the two tubes to be pulled apart and fitted with couplings 29 and 30 at the machine end of the catheter, or by an outer sleeve. The join 42 may comprise an intervening layer of different material to the tubes. A stop, such as a hub 40, may be fitted between the machine end 16 and patient end 15 to prevent the tubes being separated along the patient end region 25 of the catheter.

Description

This invention relates to catheters having two or more lumens and methods of manufacture of such catheters.

Conventional multi-lumen catheters such as CVC or PI VC catheters are usually made by extrusion. Extruded multi-lumen tubing is cut to length and connection is made to the individual lumens at the machine end by means of a separate manifold or “delta piece” joined to the end of the tubing. The manifold has a triangular or delta-shape moulded body with extension lines bonded to its wider, machine side. The extension lines are terminated at their machine end with luer or other connectors. The narrower, patient end of the delta has small diameter tubular cores that have to be inserted in the respective lumens at the machine end of the multi-lumen tubing. The delta could be preformed and secured to the tubing by bonding or it could be made by overmoulding. The small size of the components makes this a very difficult process, increasing the cost and reject rate. Also, the final catheter is inevitably formed with joints in the lumens at the manifold. This causes flow discontinuities along the catheter, which increases the risk of damage to biological liquids, such as blood, flowing along the catheter. This can lead to haemolysis and could cause thrombi. It also increases the risk of leakage.

It is an object of the present invention to provide an alternative multi-lumen catheter and method of manufacture.

According to one aspect of the present invention there is provided a multi-lumen catheter having at least two lumens extending along the catheter from a patient end to a machine end, each lumen opening towards the patient end of the catheter and at the machine end of the catheter, the at least two lumens extending along respective ones of at least two tubes continuously and uninterrupted between the patient end and the machine end of the catheter, and the at least two tubes being retained together along a patient end region of the catheter but being separate from one another along a machine end region of the catheter so that the tubes can be manipulated separately relative to one another along the machine end portion.

The at least two tubes are preferably joined together by a separable join that is separated along the length of the portions of the tubes extending along only the machine end region of the catheter. The at least two tubes may be extruded with an intervening layer between them of a different material that is slightly incompatible with the material of the tubes, and the separate portions along the machine end region being formed by the two tubes having been pulled apart from one another. Alternatively the tubes may be retained together by an outer sleeve around the tubes, the outer sleeve being absent from the machine end region to enable the tubes to be manipulated separately from one another along the machine end region, and the outer sleeve extending along the patient end region so that the two tubes are retained together along the patient end region. The catheter preferably includes stop means at the location between the machine end region and the patient end region, the stop means being arranged to prevent separation of the two tubes on the patient side of the stop means.

According to another aspect of the present invention there is provided a dual-lumen CVC catheter including includes two tubes extending continuously uninterrupted from the patient end of the catheter to its machine end, each tube having an opening towards its patient end and a coupling at its machine end, the two tubes extending side-by-side together along a patient end region to stop means, and the two tubes extending separately of one another from the stop means to their respective machine end coupling along a machine end region so that they can be manipulated separately relative to one another along the machine end region.

According to a further aspect of the present invention there is provided a method of making a multi-lumen catheter including the steps of extruding two tubes, the two tubes being retained together side by side, and subsequently separating the two tubes from one another along a region extending from the machine end of the catheter without separating the tubes along the remainder to the catheter extending to the patient end of the catheter.

The two tubes may be separated by pulling them apart from one another along a machine end region. The method may include the step of providing stop means at a location between the machine end region and the patient end region to prevent the tubes becoming separated along the patient end region. The tubes may be extruded with a join between them having a line of weakness. The two tubes may be separated by pulling them apart from one another along a machine end region. The method preferably includes the step of providing stop means at the location between the machine end region and the patient end region to prevent the tubes becoming separated along the patient end region. The tubes may be extruded with a join between them having a line of weakness. The tubes may be extruded with an intervening layer of a different material that is slightly incompatible with the material of the tubes so that a join between the tubes can be ruptured readily.

According to a fourth aspect of the present invention there is provided a method of making a multi-lumen catheter including the steps of providing two tubes retained together by an outer sleeve around both tubes, the outer sleeve being removed along a machine end region to enable the tubes to be separated from one another along the machine end region, and the sleeve remaining along a patient end region so that the two tubes are retained together along the patient end region.

According to a fifth aspect of the present invention there is provided a tube made by a method according to a further or fourth aspect of the present invention.

A two-lumen CVC catheter and its method of manufacture, both according to the present invention, will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a side elevation view of the catheter;

Figure 2 is a transverse cross-section along the line II-II of Figure 1 to an enlarged scale;

Figures 3 A to 3D show steps in the manufacture of the catheter;

Figure 4 is a transverse cross-section through an alternative catheter;

and

Figures 5 to 7 are transverse cross-sections of alternative catheters.

With reference first to Figures 1 and 2, the catheter 1 is made from plastics material having two lumens 11 and 12 extending along respective tubes 13 and 14 from the patient end 15 of the catheter to its machine end 16. The catheter 1 may be considered as having a patient end region 25 and a machine end region 26. The patient end region 25 extends along the major part of the length of the catheter 1 rearwardly from the patient end 15; the machine end portion 26 extends along a shorter, minor part of the length of the catheter forwardly from the machine end 16. The two tubes 13 and 14 can be separately manipulated at their free, machine ends and along the length of machine end region 26. At their machine ends 27 and 28 the two tubes 13 and 14 are terminated by conventional luer couplings 29 and 30.

The patient end region 25 of the catheter 1 is provided by a continuation of the two tubes 13 and 14 but along this portion the two tubes are retained together side-by-side forming a unitary structure. The catheter 1 is completed by stop means in the form of a hub 40 or similar component attached around the outside of the catheter at the machine end of the patient end portion 25 to prevent any force applied to the machine ends 27 and 28 of the tubes 13 and 14 causing them to separate beyond the hub. The hub 40 is shaped with two thin projecting portions 41 on opposite sides so that it forms a suture wing for use in securing the catheter 1 to the patient’s skin by suturing through the wing and skin adjacent the site where the catheter enters the body.

Figure 2 shows that the two tubes 13 and 14 both have a semi-circular, D-shape section and are retained together along the patient end region 25 by a join 42 between the respective flat faces 130 and 140 of each tube. This join 42 has a relatively low peel strength and is separable or rupturable by opposite forces applied to the two tubes 13 and 14 at right angles to their longitudinal axis. The join 42, however, is sufficient to ensure that the two tubes 13 and 14 remain joined together along the patient end region 25 during clinical use. In the arrangement shown in Figure 2 the two tubes 13 and 14 are made of the same material but are separated from one another along their flat faces 130 and 140 by an intervening layer 150 of a different material that is incompatible with, or is only partially compatible with, the material from which the two tubes are formed. This layer 150 forms a strip along the length of the patient end region 25. At its edges, the layer 150 reduces in thickness and extends close to the outside edge of the patient end region 25 being separated from the outer surface by thin, rupturable links 151 and 152 between the material forming the two tubes 13 and 14.

The catheter 1 is made in the manner illustrated in Figures 3A to 3D. First, as shown in Figure 3 A an extruder machine 100 with two hoppers 101 and 102 is loaded with two different plastics materials 103 and 104 such as thermoplastic polyurethane, PVC, polyethylene, polyether, TPE, FEP, acetal, polypropylene, polyamide and the like chosen to be slightly incompatible with one another. Alternatively, the same materials could be used but with additives, such as silicone, to prevent then sticking. The extruder has a die 105 with two D-shape orifices between which there is a linear orifice. The die 105 is arranged to extrude a tubing component 106 formed of two tubes 13 and 14 (of the same material 103) and the intervening strip layer 150 (of the different material 104) joined side by side with the section shown in Figure 2. The tubing 106 is then cut to lengths equal to that of the finished catheter 1 as shown in Figure 3B. As shown in Figure 3C, the next step is to grip the machine ends 27 and 28 of the two tubes 13 and 14 and pull them outwardly away from each other so that the join 42 between them tears or ruptures (by separating the strip layer 150 from one or both faces 130 and 140 of the two tubes) to give the desired length of the machine end region 26. The strip layer 150 can be subsequently trimmed off close to the point of separation of the two tubes 13 and 14. Figure 3D shows that the hub or stop 40 is now attached with the catheter 1 at the patient end of the machine region, where the tubes 13 and 14 start to separate from one another. This may be done in various ways, such as by bonding a component in two halves about the catheter 1 or by overmoulding or the like. The stop 40 could, instead, be fixed with the catheter 1 before separating the two tubes 13 and 14 along the machine end region. The couplings 29 and 30 would then be attached to the machine ends 27 and 28 of each tube 13 and 14 and the patient end 15 of the catheter 1 is end formed to smooth and round its cut end and to form any openings that may be needed.

In the catheter 1 described above the two tubes 13 and 14 are retained together by the weak bond 42 between the walls 130 and 140 of the lengths of tubing provided by the separate layer 150 but this is not the only way in which tubes can be retained together.

For example, as shown in Figure 4 the two tubes 13’ and 14’ could be extruded from different, slightly incompatible plastics (or from the same plastic with additives to reduce adhesion) without an intervening layer so that their flat faces 130’ and 140’ contact one another directly and form a weak, rupturable join between them.

Figure 5 shows another alternative arrangement where two tubes 113 and 114 are retained side-by-side together by means of an outer sleeve 115. In such an arrangement the outer sleeve 115 would be stripped off the catheter along the machine end region so that the individual tubes could be manipulated. Alternatively, the length of the outer sleeve 115 could be selected so that it leaves the required length of the tubes 113 and 114 at the machine end exposed. Such an outer sleeve could also be used with the arrangement shown in Figure

2.

The invention is not limited to catheters with two lumens but could be used with any number of two or more lumens. The lumens need not be symmetrical and of the same size and shape. Figure 6, for example shows a catheter 601 with three tubes having three lumens 602, 603 and 604 in which one is of semi-circular section and the others have smaller, sector-shape sections. Figure 7 shows a catheter 701 with a central tube 702 of circular section and two outer tubes 703 and 704 each with a C-shape section surrounding the central tube.

The invention is not confined to catheters for use in blood vessels but could be used in other multi-lumen catheters.

The present invention avoids the need to attach a separate manifold to the machine end of multi-lumen tubing, thereby considerably simplifying manufacture. Because the lumen along each tube is continuous and uninterrupted from its patient end to its machine end it ensures that liquids can flow smoothly along the lumens with a reduced risk of damage to blood or other biological fluid flowing along the catheter. The continuous lumens also avoid the risk of leakage from joins and avoid the need to inspect and test such joins.

Claims

1. A multi-lumen catheter (1) having at least two lumens (11 and 12) extending along the catheter from a patient end (15) to a machine end (16), wherein each lumen (11 and 12) opens towards the patient end (15) of the catheter and at the machine end (16) of the catheter, wherein the at least two lumens (11 and 12) extend along respective ones of at least two tubes (13 and 14,13’ and 14’, 113 and 114) continuously and uninterrupted between the patient end (15) and the machine end (16) of the catheter, and wherein the at least two tubes (13 and 14,13’ and 14’, 113 and 114) are retained together along a patient end region (25) of the catheter but are separate from one another along a machine end region (26) of the catheter so that the tubes can be manipulated separately relative to one another along the machine end portion.

2. A catheter according to Claim 1, wherein the at least two tubes (13 and 14,13’ and 14’, 113 and 114) are joined together by a separable join (42) that is separated along the length of the portions of the tubes extending along only the machine end region (26) of the catheter.

3. A catheter according to Claim 2, wherein the at least two tubes (13 and 14) are extruded with an intervening layer (150) between them of a different material that is slightly incompatible with the material of the tubes, and wherein the separate portions along the machine end region (26) are formed by the two tubes (13 and 14) having been pulled apart from one another.

4. A catheter according to any one of the preceding claims, wherein the tubes (113 and 114) are retained together by an outer sleeve (115) around the tubes, wherein the outer sleeve (115) is absent from the machine end region to enable the tubes to be manipulated separately from one another along the machine end region, and wherein the outer sleeve (115) extends along the patient end region so that the two tubes are retained together along the patient end region.

5. A catheter according to any one of the preceding claims, wherein the catheter includes stop means (40) at the location between the machine end region (26) and the patient end region (25), and wherein the stop means (40) is arranged to preventing separation of the two tubes (13 and 14) on the patient side of the stop means (40).

6. A dual-lumen CVC catheter (1), wherein the catheter includes two tubes (13 and 14) extending continuously uninterrupted from the patient end (15) of the catheter to its machine end (16), wherein each tube (13 and 14) has an opening towards its patient end (15) and a coupling (29 and 30) at its machine end, wherein the two tubes (13 and 14) extend side-by-side together along a patient end region (25) to stop means (40), and wherein the two tubes (13 and 14) extend separately of one another from the stop means (40) to their respective machine end coupling (29 and 30) along a machine end region (26) so that they can be manipulated separately relative to one another along the machine end region.

7. A method of making a multi-lumen catheter (1) including the steps of extruding two tubes (13 and 14), the two tubes being retained together side by side, and subsequently separating the two tubes (13 and 14) from one another along a region extending from the machine end (16) of the catheter without separating the tubes along the remainder to the catheter extending to the patient end (15) of the catheter.

8. A method according to Claim 7, wherein the two tubes (13 and 14) are separated by pulling them apart from one another along a machine end region (26).

9. A method according to Claim 7 or 8 wherein the method includes the step of providing stop means (40) at a location between the machine end region (26) and the patient end region (25) to prevent the tubes becoming separated along the patient end region.

10. A method according to any one of Claims 7 to 9, wherein the tubes (13 and 14) are extruded with a join (42) between them having a line of weakness.

11. A method according to Claim 10, wherein the tubes (13 and 14) are extruded with an intervening layer of a different material (150) that is slightly incompatible with the material of the tubes so that a join between the tubes can be ruptured readily.

12. A method of making a multi-lumen catheter including the steps of providing two tubes (113 and 114) retained together by an outer sleeve (115) around both tubes, wherein the outer sleeve (115) is removed along a machine end region to enable the tubes to be separated from one another along the machine end region, and wherein the sleeve (115) remains along a patient end region so that the two tubes (113 and

114) are retained together along the patient end region.

13. A tube (1) made by a method according to any one of Claims 7 to 12.