Manufacture of tracheostomy tubes and their components

Abstract

A tracheostomy tube flange (13) of liquid silicone material has openings (14) near each end for receiving the ends of the neck strap. The openings (14) are reinforced by overmolding inserts (137, 138) of a heat cured silicone material having a hardness similar to that of the flange material. The inserts (137, 138) have outwardly projecting ledges (144) between their ends.

Description

[Technical Field]

[0001] The present invention relates to a tracheostomy tube of the type that includes a shaft and a mounting flange near the machine end of the shaft, the mounting flange extending radially outwardly of the tube and having openings near each end into which means for holding the tube against a patient's neck can be secured. [Background technology]

[0002] Tracheostomy tubes are used to allow a patient to ventilate, respire, or breathe spontaneously. Endotracheal tubes are inserted through the mouth or nose so that one end is located within the trachea and the other end is located outside the patient. Tracheostomy tubes are inserted into the trachea through a surgically created opening in the neck. Tracheostomy tubes can be inserted by different techniques, such as a surgical cut-down technique, which is performed in an operating room, or a cricothyrotomy technique, which may be performed in an emergency.

[0003] Tracheostomy tubes are typically used for long-term ventilation or when insertion of an artificial airway into the mouth or nose is not possible. Patients are often conscious while breathing through the tracheostomy tube, which may be vented to atmosphere or connected by tubing to some form of mechanical ventilator. The tube is secured in place around the patient's neck by mounting flanges secured to the mechanical end of the tube shaft and positioned to extend outward on either side of the tube. A necktie or the like is placed around the patient's neck, with its ends secured to each end of the flange. Alternatively, sutures can be used to secure the flanges in place.

[0004] Tracheostomy tubes can be made from a variety of materials, typically a flexible plastic material such as PVC, polyurethane, or silicone. Silicone is particularly suitable because it provides softness, comfort, and conformability. This is particularly advantageous for tracheostomy tubes because patients may be intubated and use a ventilator for extended periods of time, typically a week or more. Silicone is also advantageous because it is not damaged by the high temperatures of an autoclave, allowing silicone tubes to be washed and autoclaved for reuse.

[0005] It is particularly desirable to mold the mounting flange of a tracheostomy tube from a soft, conformable plastic, such as silicone, so that it easily flexes and conforms to the surface of the patient's neck. However, flanges molded from soft plastic materials can pose a problem in that they may not be strong enough to prevent the flange from tearing where a neck strap or suture is inserted through the opening used to secure the tube to the patient's neck. Some mounting flanges made from silicone materials, such as liquid silicone rubber, are less resistant to abrasion from ties made of relatively rigid materials, especially those using hook-and-loop (Velcro)-type fasteners. Over several days, abrasion can become so severe that it penetrates the edge of the flange opening. If unnoticed by the caregiver, this can lead to decannulation. Similar problems can occur when sutures are used with the flange. To reduce this risk, it has been proposed to add a hard plastic reinforcing member around the tie opening, as described in U.S. Patent No. 5,629,494. Such a reinforcing member poses the challenge of preventing the insert from separating from the rest of the flange due to the different compositions of the flange and insert. Generally, the contact area between the insert and the flange should be primed to reduce the risk of the insert peeling, dislodging, or separating from the flange. Flexure of the flange material relative to the insert can cause microcracks and crevices in the flange material, which can harbor bacteria that can lead to fistula infections. It is important to ensure that any reinforcing members do not separate from the flange, as such loose members may be or pose concerns that they may be aspirated. Some materials used to reinforce flange openings can be damaged by high temperatures, rendering the entire tube unsuitable for autoclave cleaning. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] U.S. Patent No. 9,457,164 Summary of the Invention [Problem to be solved by the invention]

[0007] It is an object of the present invention to provide an alternative tracheostomy tube and a method for manufacturing the tube and its flange. [Means for solving the problem]

[0008] According to one aspect of the present invention there is provided a tracheostomy tube of the type described above, characterized in that the flange is made of a first silicone material overmolded onto two reinforcing inserts at each of the openings, the reinforcing inserts being made of a heat-vulcanized silicone rubber material different from the first silicone material.

[0009] The silicone materials of the flange and the insert preferably have similar hardnesses. Both silicone materials have a hardness of approximately 70 Shore A. The first silicone material is preferably liquid silicone rubber. The insert may include a hollow tubular body with a passageway therethrough and a protrusion extending outwardly of the body between opposite ends. The protrusion may be an annular ledge extending around the body. The opposite sides of the flange are preferably flush with the opposite ends of the insert body, the passageway through each body extending through the thickness of the flange, and the opposite sides of the protrusion are covered by the material of the flange.

[0010] According to another aspect of the present invention, there is provided a method of manufacturing a mounting flange for a tracheostomy tube, the method comprising the steps of: molding two inserts of heat vulcanized silicone rubber material, each insert having a passageway therethrough and an outer projection; and overmolding a silicone material different from the material of the inserts around the outer projections of the two inserts to form the mounting flange for the tube, the passageway through each insert providing openings into which fixing means can be secured near each end of the flange.

[0011] Preferably, the silicone material of the insert has substantially the same hardness as the silicone material overmolded onto the insert.

[0012] According to yet another aspect of the present invention, there is provided a method of manufacturing a tracheostomy tube, the method comprising the steps of manufacturing a mounting flange according to the method of the above-described other aspect of the present invention, providing a tube shaft having a patient end and a machine end, and attaching the mounting flange to the shaft near the machine end of the shaft.

[0013] According to a fourth aspect of the present invention, there is provided a tracheostomy tube manufactured by the method of the above further aspect of the present invention.

[0014] A tracheostomy tube with a mounting flange according to the present invention and a method of manufacturing the mounting flange and tube will now be described, by way of example, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a perspective view of the machine end of the tube from the patient end of the tube. [Figure 2] FIG. 10 is an enlarged perspective view of a portion of the mounting flange of the tube across one of the flange openings and without the shaft. [Figure 3] FIG. 10 is an enlarged perspective view of the mounting flange insert. DETAILED DESCRIPTION OF THE INVENTION

[0016] Referring initially to FIG. 1 , the tracheostomy tube 1 has a curved shaft 10 of circular cross-section molded from a flexible plastic such as silicone. The patient, distal, or front end 11 of the tube 1 is adapted to be positioned within the trachea. The machine, proximal, or rear end 12 of the tube 1 extends through the tracheostomy and leads to the exterior of the patient. The machine end 12 of the tube supports a laterally extending mounting flange 13 adapted to rest against the skin of the neck and has openings 14 at each end for receiving a fastening means, such as the end of a neck tie (not shown), that extends around the neck. Alternatively, the fastening means can take the form of a suture threaded through the skin adjacent the flange 13. The machine end 12 of the tube 1 also includes an externally tapered 15 mm male connector 15 arranged to receive a mating female connector (not shown) on one end of the ventilation tube. The illustrated connector 15 is a separate component from the shaft 10 and is molded from a harder plastic than the shaft. Alternatively, the connector can be an integral, unitary component of the shaft. If the patient is spontaneously breathing, the connector may not be necessary, and the shaft can terminate in a low-profile end fitting. While the tube 1 is shown without a sealing cuff, it can also be provided with other conventional features such as a conventional sealing cuff and a phonation window or suction lumen.

[0017] 2, the rear end of shaft 10 terminates in an enlarged outer circular boss 16 which extends through a central opening 30 in mounting flange 13. Flange 13 has a circular collar 31 formed around opening 30 and protruding from the rear face of the flange. Collar 31 defines a circular cavity 32 into which boss 16 of shaft 10 is received and coupled.

[0018] The mounting flange 13 is molded from a relatively soft, conformable silicone material, preferably liquid silicone rubber having a hardness of approximately 70 Shore A. This is preferably the same material forming the shaft 10. The flange 13 has two radial arms 131 and 132 that project outward from the central collar 31 along an axis perpendicular to the curvature of the shaft 10. The inner portion of each arm 131 and 132 has a width approximately half the diameter of the collar 31. At their outer ends, each arm 131 and 132 flares outward from tapered regions 133 and 134 to enlarged regions 135 and 136, the width of which is approximately twice the width of the inner portion of the arm. Openings 14 for accommodating the ends of neckties or the like are provided in these enlarged regions 135 and 136 and are reinforced by respective inserts 137 and 138, shown more clearly in FIG. 3. The inserts 137 and 138 are held against the flange 13 by overmolding the flange material onto the outside of the inserts.

[0019] The inserts 137 and 138 are also molded from a silicone material, but a higher-temperature-resistant grade of silicone material than that forming the main portion of the flange 13, i.e., a heat-vulcanized silicone rubber such as MED-4070 from Avantor, Inc., with a hardness similar to that of the flange material. It has been found that by fabricating both the insert and the flange from a silicone material, it is possible to achieve a very good bond without cracking or separation, even after extended use and flexing. Having similar hardnesses for the two materials also has the advantage that the inserts do not increase the stiffness of localized areas of the flange. The inserts 137 and 138 have a generally rectangular shape with a flat, radially extending plate 140. The plate 140 is rectangular with rounded corners and has a thickness approximately one-quarter the thickness of the flange arms. From the center of each side of the plate 140 protrudes a hollow tubular body formed by identical walls 141 and 142 in the shape of an elliptical racetrack with rounded edges 143. The lateral outer diameter of the walls 141 and 142 is smaller than the outer diameter of the plates such that the central plate 140 forms an annular outer projection, ledge, or ring 144 having a forward-facing upper surface 145 and a rearward-facing lower surface 146. The upper and lower surfaces 147 of the walls 141 and 142 have flat outer regions 148 that continue as rounded inner regions 149. This provides a smooth entrance to the central elongated passageway 150 through the inserts 137 and 138 that form the opening 14. The inserts 137 and 138 are recessed into the arms 131 and 132 of the mounting flange 13 with the passageway 150 in each insert extending perpendicular to the length of the arm. The height of the inserts 137 and 138 is equal to the thickness of the arms so that both surfaces of the arms 131 and 132 are flush with the flat end outer regions 148 of the inserts. A ledge 144 on each insert 137 and 138 projects outward into the flange material midway through the thickness of arms 131 and 132. The compatibility of the silicone material used in the main portion of flange 13 and inserts 137 and 138 means that the flange material forms a strong bond with the outside of the insert, around the outer surfaces of upper and lower walls 141 and 142, along the upper and lower surfaces of ledge 144 and around its outer edge. The bond between the flange material and the insert does not require any priming or other pre-treatment.The bond formed with inserts 137 and 138 resists bending and flexing of flange 13 without causing separation or delamination, and without forming cracks or gaps where bacteria can collect. Inserts 137 and 138 have a hardness similar to the material of the rest of flange 13, thereby avoiding stiffness differences across the flange. In use, both ends of a tie or suture are threaded or otherwise secured through passages 150 in inserts 137 and 138. The abrasion resistance of the material of inserts 137 and 138 ensures that friction caused by the forces and movement of the tie or suture during use does not damage flange 13, while still maintaining the softness and conformability of the flange.

[0020] The mounting flange 13 is manufactured by first molding inserts 137 and 138 from a heat-vulcanized silicone rubber material, then overmolding a liquid silicone rubber material onto the inserts to form the remainder of the flange. To manufacture the complete tracheostomy tube 1, the shaft 10 is molded separately, preferably from the same silicone material as the flanges or a similar silicone material compatible with the flange material for bonding. The main portion of the shaft is overmolded or otherwise attached to the patient end of a preformed connector 15 made of a hard plastic material. The shaft 10 is inserted through the central opening 30 of the flange 13, and a suitable bonding solution is applied to the outside of the enlarged boss 16 near the machine end of the shaft and to the inside 32 of the central collar 31 of the flange.

Claims

1. 1. A tracheostomy tube comprising a shaft (10) and a mounting flange (13) near a machine end (12) of the shaft, the mounting flange (13) extending radially outward of the tube and having openings (14) near each end into which means for holding the tube against a patient's neck can be secured, the flange (13) being made of a first silicone material overmolded with two reinforcing inserts (137, 138) at each of the openings (14), the reinforcing inserts (137, 138) being made of a heat-vulcanized silicone rubber material different from the first silicone material.

2. 2. A tracheostomy tube according to claim 1, characterized in that the silicone material of the flange (13) and the inserts (137, 138) have similar hardness.

3. 3. The tracheostomy tube of claim 2, wherein both silicone materials have a hardness of about 70 Shore A.

4. 4. The tracheostomy tube according to claim 1, wherein the first silicone material is liquid silicone rubber.

5. A tracheostomy tube according to any one of claims 1 to 4, characterized in that the insert (137, 138) comprises a hollow tubular body (141, 142) having a passage (150) therethrough, and a protrusion (144) extending outside the body (141, 142) between both ends.

6. A tracheostomy tube according to claim 5, characterized in that the protrusion is an annular ledge (144) extending around the body (141, 142).

7. 7. A tracheostomy tube according to claim 5 or 6, characterized in that both sides of the flange (13) are flush with both ends (147) of the body (141, 142) of the insert (137, 138), the passage (150) through each body passes through the thickness of the flange (13), and both sides of the protrusion (144) are covered by the material of the flange (13).

8. 1. A method of manufacturing a mounting flange (13) for a tracheostomy tube, the method comprising the steps of: molding two inserts (137, 138) of a heat-vulcanized silicone rubber material, each insert having a passageway (150) therethrough and an outer projection (144); and overmolding a silicone material different from the material of the inserts around the outer projections (144) of the two inserts (137, 138) to form the mounting flange (13) for the tube, wherein the passageway (150) through each insert provides openings (14) near either end of the flange (13) into which a fixing means can be fixed.

9. 9. The method of claim 8, wherein the silicone material of the insert (137, 138) has substantially the same hardness as the silicone material overmolded onto the insert.

10. 10. A method of manufacturing a tracheostomy tube, comprising the steps of: manufacturing a mounting flange (13) according to the method of claim 8 or 9; providing a shaft (10) of the tube having a patient end (11) and a machine end (12); and attaching the mounting flange (13) to the shaft (10) near the machine end (12) of the shaft.

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