REINFORCED MEDICO-SURGICAL TUBES AND THEIR MANUFACTURE

Abstract

A tracheostomy tube (1) has a shaft (10, 10) including a helical reinforcing wire (30) overmoulded by a plastics material, such as of silicone. The wire has an indented path (31) traversing its turns in which is received a small-bore tube (32) so that this does not project above the surface of the shaft, or only forms a small projection. The small-bore tube (32) acts as an inflation line and opens at its patient end (33) within a sealing cuff (13). The machine end of the tube (32) is terminated by a combined inflation indicator and connector (36).

Claims

1-14. (canceled)

15. A reinforced medico-surgical tube having a shaft of a first, plastics material reinforced along at least a part of its length by a helical member of a second, stiffer material and embedded with the first material, characterised in that the helical member has a longitudinal path along a part at least of its length extending transversely of the turns of the helical member, and that the tube includes an elongate member extended along a part at least of the length of the longitudinal path so that a part at least of the thickness of the elongate member is received in the longitudinal path.

16. The tube according to claim 15, characterised in that the longitudinal path is provided by an indentation in the helical member.

17. The tube according to claim 15, characterised in that the longitudinal path is provided by notches in the helical member.

18. The tube according to claim 15, characterised in that the longitudinal path is provided by a gap in the helical member.

19. The tube according to claim 15, characterised in that the elongate member is a small-bore tube extending longitudinally along a part at least of the length of the longitudinal path so that a part at least of the thickness of the small-bore tube is received in the longitudinal path.

20. The tube according to claim 15, characterised in that the tube has an inflatable sealing cuff towards its patient end, and that the patient end of the small-bore tube opens into the sealing cuff.

21. The tube according to claim 15, characterised in that the helical member is of a metal wire.

22. the tube according to claim 15, characterised in that the metal wire is of titanium.

23. The tube according to claim 15, characterised in that the plastics material includes silicone.

24. The tube according to claim 15, wherein the tube is a tracheostomy tube.

25. A method of making a reinforced medico-surgical tube including the steps of providing a helical reinforcing member of a relatively stiff material with a longitudinal path along a part at least of its length, extending an elongate member along the path, and overmoulding the reinforcing member and elongate member with a relatively flexible plastics material.

25. A method of making a reinforced medico-surgical tube including the steps of providing a helical reinforcing member of relatively stiff material, deforming the outside of the helical reinforcing member inwardly to form an elongate indented groove along a part at least of the length of the reinforcing member, extending an elongate member along the groove and overmoulding the reinforcing member and elongate member with a relatively flexible plastics material.

26. A method according to claim 25, characterised in that the method includes the steps of providing an anvil extending through the helical reinforcing member, the anvil having a groove extending longitudinally on its outside along a part at least of its length, using a die to deform a part of the helical reinforcing member into the groove on the anvil so as to form the indented groove in the helical reinforcing member, and subsequently removing the anvil and die from the reinforcing member.

Description

[0015] FIG. 1 is a perspective view of the tracheostomy tube;

[0016] FIG. 2 is a cross-sectional transverse view of the tube of FIG. 1;

[0017] FIG. 2A is a cross-sectional transverse view of a modified tube:

[0018] FIG. 3 is a side view of the reinforcing wire at an initial stage of manufacture;

[0019] FIG. 4 illustrates a subsequent stage in the manufacturing process;

[0020] FIG. 5 is a perspective view of the reinforcing wire after forming a groove;

[0021] FIG. 6 is a perspective view of an alternative reinforcing wire;

[0022] FIG. 7 is a perspective view of a different configuration of reinforcement; and

[0023] FIG. 8 is an end view of an alternative tube.

[0024] With reference first to FIGS. 1, 2 and 2A the tracheostomy tube 1 has a curved shaft 10 of circular section and with an outer diameter of around 12 mm. The shaft 10 has a moulded, tubular wall 110 of a relatively soft plastics material. The shaft 10 has a patient end 12 adapted to be located within the trachea of the patient and has a conventional inflatable sealing cuff 13 towards its patient end. The cuff 13 shown is of the high-pressure kind made of an elastic material that lies close to the shaft 10 when deflated and is stretched outwardly when inflated. The cuff 13 is attached to the outside of the shaft 10 by two collars 14 and 15 at opposite ends. The shaft 10 and cuff 13 are both moulded of a silicone material. It will be appreciated that the tube could be of a different sizes, shapes and materials according to the application and that the cuff could be of the low-pressure kind

[0025] The machine end 16 of the shaft 10 is adapted, during use, to extend externally through the tracheostomy opening formed in the patient's neck. The machine end 16 of the shaft 10 is bonded with a hub or connector 17 having a conventional 15 mm male tapered outer surface 18. The connector 17 is adapted to make a removable push fit in a conventional 15 mm female connector (not shown) at one end of a breathing tube extending to a ventilator or anaesthetic machine. Alternatively, the machine end of the tube 1 could be left open to atmosphere when the patient is breathing spontaneously. The tracheostomy tube 1 also includes a radially extending support flange 20 adapted to lie against the skin surface of the neck on either side of the tracheostomy stoma. The flange 20 is moulded integrally as one part with the shaft 10 at its machine end 15, although the flange and connector could be formed separately and be subsequently attached. The flange 20 has openings 21 at opposite ends for attachment to a neck strap (not shown) used to support the tube with the patient's neck.

[0026] The shaft 10 has a reinforcement member 30 that extends along and around the shaft and is embedded with the wall 110 of the shaft by overmoulding. More particularly, the reinforcing member 30 is a helically-wound metal wire such as of titanium or stainless steel. The reinforcing wire 30 is formed with a groove 31 extending longitudinally along one side of the curve of the shaft 10, the groove being indented inwardly. A small-bore inflation line tube 32 extends along the groove 31 outside the helical reinforcement member 30 and opens at its patient end 33 beneath the trachea-sealing cuff 13 between the two collars 14 and 15. The inflation line 32 and the reinforcement member 30 are both encased in the silicone material of the wall of the shaft. The groove 31 in the reinforcement member 30 receives the thickness of the inflation line 32 sufficiently to ensure that it does not form any projection, or only forms a shallow projection, on the outside of the shaft 10. FIG. 2A shows a modified tube 10′ where the silicone plastics of the tube wall extends over the inner surface of the reinforcement member 30′ as well as its external surface.

[0027] The machine end of the inflation line 32 extends through the flange 20 and continues unattached with the shaft 10 being terminated by a conventional combined inflation indicator and valve 36.

[0028] In some cases it may be preferred for the reinforcement member 30 not to extend along the entire length of the shaft, such as when it is necessary to form a region that is softer, such as at the patient end 12. In some cases, it may be necessary to form a region that is not malleable, so as to prevent the lumen being closed if the reinforced section of the tube is inadvertently compressed or pinched

[0029] The shaft 10 of the tube 1 is made using steps shown in FIGS. 3 to 5. First, as shown in FIG. 3, a metal wire 30″ is wound into a helical coil shape 30. This coil 30 may be formed initially or it may be formed by winding directly onto an anvil or former 50 shown in FIG. 4. The wire 30″ is shown as having a circular section but it could have other shape cross sections. For example, a wire with a rectangular or oval section could enable the wall of the tube to be thinner if the wire is wound with its wider side aligned longitudinally of the length of the tube. The anvil 50 is of cylindrical shape and circular section having a diameter equal to the desired internal diameter of the helical coil 30. The anvil 50 has a groove 51 extending along its length on its outer surface. A die 52 is positioned above the anvil 50 in alignment with the groove 51 and is mounted for reciprocating movement down into the groove and up out of the groove. With the coil 30 mounted around the anvil 50, the action of moving the die 52 downwardly causes it to engage that part of the coil above the groove 51 and deform the coil down into the groove. The metal of the coil 30 is preferably malleable so that the coil is permanently deformed with the groove 31 along its length, as shown in FIG. 5. The coil 30 is then removed from the anvil 50 and placed on a suitable mould tool (not shown), the inflation line 32 being extended along the groove 31. The silicone or other soft plastics material of the wall of the shaft 10 is then overmoulded about the coil 30, flowing between its turns and covering the inflation line 32 to form a smooth outer surface of the shaft or both a smooth outer and inner surface. The flange 20 can also be integrally moulded with the shaft 10 at this stage. The sealing cuff 13 is then attached in the usual way, after forming the opening 33 to the patient end 33 of the inflation lumen 32. The machine end of the inflation line 32 is joined with the combined inflation indicator, valve and connector 36.

[0030] The arrangement of the present invention enables a tube of a relatively soft and flexible plastics material to be reinforced effectively against kinking and crushing without the inflation line or other elongate member protruding along the outer surface or protruding into the lumen of the tube.

[0031] The invention is not limited to cuffed tubes but could be used with tubes having, for example, a suction or irrigation lumen, or a lumen for gas-sampling or for supplying a therapeutic gas or liquid. Other elongate members could extend along the groove in the helical reinforcement instead of, or in addition to, a small-bore tube. The elongate member could, for example, be an electrical wire, such as for connection to an electrical sensor, or a fibre-optic cable, such as for viewing purposes or for supplying radiation to a body cavity. The invention is not limited to tracheal tubes but could be used in other medico-surgical tubes, such as urinary catheters or chest drainage tubes.

[0032] The helical reinforcement member need not be of a metal but could, for example, be of a stiff plastics material. With some materials it might be necessary to use a heated die to enable the coil to be deformed and to set in the groove shape. The reinforcement member need not extend along the entire length of the tube since in some tubes it might only be necessary to reinforce a part of the tube. In some tubes the small bore tube or other elongate member might only extend along a part of the length of the reinforced portion of the tube, in which case the groove in the outside of the coil need not extend along its entire length.

[0033] Instead of an indented notch in the reinforcement member, as shown in FIGS. 1, 2, 4 and 5, a longitudinal path could be provided along the reinforcement member in other ways. For example, a longitudinal path 130 could be provided by a cut-out notch 131, as shown in FIG. 6. A path for receiving an elongate member could be provided in other ways, such as shown in FIG. 7 where the turns of the reinforcement coil 230 are bent back on themselves in boustrophedon fashion to leave a path 231 extending longitudinally along the coil. The bent portions of the coil 230 would preferably have rounded corners and not the square corners shown in the Figure. FIG. 8 shows how the wall thickness could vary around the circumference of the tube, being thickest in the region where the elongate member 332 extends and without any protrusion on the inner or outer surface.