This invention relates to medico-surgical tubes of the kind including a connector component at the machine end of the tube and a tubing component connected at its machine end with the connector component, the connector component including a coupling surface towards its machine end and an opening at its patient end having a diameter closely matched with the external diameter of the tubing component.

The invention is more particularly, but not exclusively, concerned with tracheostomy tubes and methods of assembly of such tubes.

Tracheostomy tubes are used to enable ventilation or respiration of a patient. The tube is inserted into the trachea via a surgically-formed opening in the neck so that one end locates in the trachea and the other end locates outside the patient adjacent the neck surface. Various types of different tracheostomy tubes are presently available to suit different needs. The tracheostomy tube usually comprises a length of tubing and a separate connector or hub to which the machine end of the tubing is permanently attached. The connector locates at the surface of the skin and is usually provided with formations by which a neck strap is attached to the connector so as to secure the tube in place. It is particularly important that the tubing be attached with the connector in a secure manner to ensure that the tubing does not detach from the connector. If the tubing should detach from the connector it could be inhaled into the trachea of the patient leading to a risk of suffocation. The tubing and connector are often made of different materials because the tubing needs to be flexible whereas the connector needs to be more rigid. Also, the tubing and connector are usually made by different methods, typically the tubing being extruded and the connector moulded. These different manufacturing methods may mean that different materials have to be used for the different components. The different materials from which the tubing and connector are formed make it more difficult to form a secure connection between the two parts. Typically, the tubing and connector are joined by means of a weld, such as an RF weld between the outside of the tubing and an opening at the patient end of the connector. It is particularly difficult to form a secure join by this method when the tube is of a small size, such as for paediatric or neonatal use with a tubing external diameter between around 2.0mm to 6.00mm.

It is an object of the present invention to provide an alternative medico-surgical tube and method of assembly of such a tube

According to one aspect of the present invention there is provided a medico-surgical tube of the above-specified kind, characterised in that the tube includes a bonded join between the outside of the tubing component and the opening of the connector component, that the tubing component has an integral radially-enlarged machine end portion with a diameter greater than that of the opening, and that the enlarged machine end is located within the connector component on the machine side of the opening.

The bonded join between the tubing component and the connector component preferably includes at least one of the group comprising a weld, a solvent and an adhesive. The radially-enlarged machine end portion of the tubing component is preferably tapered and the connector component preferably has a recess tapered to match the taper on the machine end of the tubing component. The connector component may have an annular step surrounding the tapered recess, and the machine end of the tubing component may lie level with the step. The tube preferably includes a bonding substance between the radially- enlarged machine end portion of the tubing component and a surface of the connector component contacted by the radially-enlarged machine end. The connector component preferably includes two straps projecting outwardly and arranged to receive a neck strap for securing the tube about the neck of a patient. The tube is preferably a paediatric or neonatal tracheostomy tube. According to another aspect of the present invention there is provided a method of assembly of a medico-surgical tube including the steps of: providing a first, machine end connector component having a coupling surface towards one end to which a cooperating connector can be mated, the connector component having a recess surrounded by the coupling surface and communicating with an opening extending through of a floor of the connector component at its patient end, providing a second, tubing component having an external diameter closely matched with the diameter of the opening in the connector component, forming a radially-enlarged integral portion at the machine end of the tubing component larger than the diameter of the opening, extending the tubular component through the opening in the connector component, and bonding the outside of the tubing component with the opening, the enlarged portion on the tubing component being within the recess adjacent the floor of the connector component.

The radially-enlarged integral formation is preferably formed by inserting the machine end of the tubing component through a passage in an anvil that opens into an outwardly-flared recess and that the mandrel is used to flare the tubing outwardly against the surface of the recess. The method preferably includes the step of applying a bonding solution between the radially-enlarged integral formation on the tubing component and the floor of the connector component.

According to a third aspect of the present invention there is provided a medico- surgical tube made by a method according to the above other aspect of the present invention.

A paediatric tracheostomy tube and its method of assembly 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 cross-sectional side elevation view of the tube;

Figure 2 is a plan view of the tube from its machine end;

Figure 3 shows a preliminary step in manufacture of the tubing used in the tube;

Figures 4 and 5 show two subsequent steps in manufacture of the tubing; and

Figure 6 shows a further subsequent step in assembly of the tubing with the connector.

With reference first to Figures 1 and 2 there is shown a tracheostomy tube for paediatric or neonatal use formed of two components, namely a connector component 1 and a tubing component 2. The two components may be formed of two different materials, or different grades of plastics best suited for the nature and purpose of the components and their respective methods of manufacture. In particular, the connector component 1 is normally moulded of a relatively stiff plastic, whereas the tubing component 2 is extruded from a more flexible material.

The connector component 1 comprises a central, cylindrical coupling 10 with an external coupling surface 11 tapered slightly along its length, increasing in diameter from its machine end 12 to its patient end 12 A. The coupling surface 11 provides a male connector adapted to receive a mating female connector (not shown). Alternatively, the inside surface of the coupling could be tapered so as to receive within it a cooperating mating male connector. The coupling 10 is open at its machine end 12 and internally has a cylindrical wall 13 defining a cavity 130 within it. A floor 14 at the patient end of the coupling is closed apart from a central, circular opening 15. The opening 15 extends from the interior 130 of the coupling 10 and opens on the lower patient side of the component 1. The floor 14 is countersunk, sloping towards the opening 15 to provide a tapered, frusto-conical surface or recess 16 surrounded by an annular step 17. The connector component 1 also includes two integral, elongate straps 18A and 18B projecting radially outwardly in opposite directions from the lower, patient side of the component. Each strap 18 A and 18B includes an opening 19A and 19B towards its outer end through which a neck strap (not shown) can be threaded for use in securing the tube about the neck of the patient.

The tubing component 2 is extruded from a plastics material, such as PVC or polyurethane and has a circular section with an external diameter equal to that of the opening 15 in the connector component 1. The main shaft 20 of the component 2 may have a naturally straight shape and be flexible enough to conform readily to the patient's anatomy or it may be formed after extrusion with a curve along its length. Alternatively, it may be formed with straight portions at its machine and patient ends joined by a curved mid-section. At its machine end 21 the tubing component 2 has an integral, short outwardly-flared or tapered portion 22 with an enlarged diameter about twice that of the main part of the shaft 20 and twice the diameter of the opening 15 through the connector component 1. The taper angle of the flared portion 22 on the tubing component 2 is the same as that of the tapered, countersunk recess 16 in the floor 14 of the connector component 1 so that the flared portion of the tubing lies closely against the floor of the connector component and its end face lies level with the annular step 17 around the countersunk recess.

The tubing component 2 is secured with the connector component 1 by means of a bonded join 23 between the outside of the tubing and the passage through the opening 15. This join 23 may be formed by any suitable known technique, such as RF welding, a solvent or adhesive bond. Any gap between the underside of the flared portion 22 and the floor 14 could be filled by the same solvent or adhesive used to form the bond in the opening 15, so as to avoid any traps in which contamination could build up.

The enlarged flared portion 22 at the machine end 21 of the tubing 2 prevents the machine end of the tubing passing through the opening 15. In this way, there is no risk that the tubing 2 could be separated from the connector component 1 and inhaled into the patient even if the bonded join 23 should break down.

The tube is made by forming the connector portion 1 and the tubing portion 2 separately and then subsequently joining them together.

The connector portion 1 is made by any conventional technique such as injection moulding.

The tubing portion 2 is made in the manner shown in Figures 3 to 6 of the accompanying drawings. Figure 3 shows the first step in making the tubing portion 2 by using an extruder machine 3 to form a continuous length of tubing of circular section from plastics pellets 26. The tubing is cut into lengths 20 using a cutter 4, each length being equal to the desired length of the tubing component 2. The next step is shown in Figure 4 and involves a swaging or flaring tool 5 including an anvil 50 with a central passage 51 adapted to receive one of the lengths 20 of tubing. At its upper end the passage 51 opens into an outwardly flared recess 52 having the same angle as that desired on the underside of the flared portion 22 of the tubing component 2. At its lower end the anvil 50 includes a clamp 53 to retain the tubing 20 in position. The tool 5 also includes a reciprocating mandrel 54 that is movable up and down in alignment with the passage 51 through the anvil 50. The mandrel 54 has a narrow nose 55 adapted to fit within the bore of the tubing 20. At its upper end the nose 55 flares gradually outwardly into a tapering portion 56 corresponding to the angle of the flared portion 22 on the tubing 2. The mandrel 54 may be heated to soften the material of the tubing 20. As the mandrel 54 moves down, its nose 55 enters the upper, machine end of the tubing 20 and its heat starts to soften this part of the tubing. As the mandrel 54 moves further down, its flared part 56 enters the tubing 20, thereby starting to expand this part of the tubing. Further downward movement of the mandrel 54 swages the wall of the tubing 20 outwardly and into contact with the flared recess 52 in the anvil 50, as shown in Figure 5. The mandrel 54 is then retracted up out of the tubing 20 and out of the anvil 50. The thermal mass of the anvil 50 causes the temperature of the plastics material of the upper end of the tubing 20 to drop so that it sets with the enlarged flared head portion 22. The clamp 53 is then released and the tubing 20 is pushed up out of the anvil 50 and used in the next step where it is assembled in the connector portion 1. Figure 6 shows this next step of assembly where the patient end of the tubing 20 is pushed down through the opening 15 in the connector portion 1. The tubing 20 is pushed down until the lower, patient side of the flared portion 22 lies against the countersunk recess 16 in the floor 14 of the connector portion 1 and the upper, machine end face of the tubing lies level with the surrounding annular step 17.

The outer surface of the tubing 20 below the flared portion 20 and within the opening 15 is then bonded to the opening through the connector portion 1. This may be done by any conventional technique, such as RF welding, or by means of a solvent or adhesive. Additionally, a small amount of a bonding solution such as a solvent or the like may be placed under the lower surface of the flared portion 22 between the flared portion and the countersunk recess 16 to fill any gap and prevent the formation of any site at which contamination might accumulate.

Although the invention is particularly useful in paediatric and neonatal

tracheostomy tubes where it is very important to avoid separation between the connector piece and the tubing it could also be used in adult tracheostomy tubes and in other tubes with separately formed tubing and connector components. The flared portion at the machine end of the tubing need not be formed before inserting the tubing in the connector portion. Instead, the tubing could be bonded into the passage through the connector portion to leave a length at its machine end projecting into the inside of the connector portion. A flaring or swaging tool would then be inserted in the bore of the machine end of the tubing and the tubing flared outwardly and downwardly onto the floor of the connector portion.