GB2552250A

GB2552250A - Cuffed tubes

Info

Publication number: GB2552250A
Application number: GB1708151.4A
Authority: GB
Inventors: Aslam Aqeel; Thomas Jeffrey Andrew; Steven Veasey Neil
Original assignee: Smiths Medical International Ltd
Current assignee: Smiths Medical International Ltd
Priority date: 2016-05-26
Filing date: 2017-05-20
Publication date: 2018-01-17
Also published as: GB201609646D0; GB201708151D0

Abstract

A reinforced cuffed tube 1 with a sealing cuff 13 at its patient end 12 has a helical reinforcement 30, preferably of metal wire, and a separate inflation line 31, preferably of plastic, wound helically in parallel with the wire and between its adjacent turns, both being embedded within the wall of the shaft 10 of the tube 1. The shaft 10 may extend beyond a neck flange 20 to a machine end connector 15. The reinforcement wire 30 continues between the flange 20 and the connector 15 but the inflation line 31 connects with an inflation tube 34 at the flange. The tube has application as a paediatric tracheostomy tube. The tube is manufactured by wrapping the reinforcement wire and the inflation line helically around the outside of a mandrel, then dipping in or overmoulding with silicone before removing the shaft from the mandrel with the wire and line embedded in the shaft wall.

Description

(71) Applicant(s):

Smiths Medical International Limited (Incorporated in the United Kingdom)

1500 Eureka Park, Lower Pemberton, ASHFORD, Kent, TN25 4BF, United Kingdom (72) Inventor(s):

Aqeel Aslam Andrew Thomas Jeffrey Neil Steven Veasey (74) Agent and/or Address for Service:

Smiths Medical

Lammas Park Road, Ealing, LONDON, W5 5JD, United Kingdom (51) INT CL:

A61M 16/04 (2006.01) A61M 25/00 (2006.01) A61M 25/10 (2013.01) (56) Documents Cited:

EP 1103280 A1 EP 0852954 A2

EP 0102422 A1 WO 2015/075412 A1

US 4990143 A

JP H0759857 (58) Field of Search:

INT CLA61M

Other: EPODOC & WPI; Patent Fulltext (54) Title ofthe Invention: Cuffed tubes Abstract Title: Reinforced cuffed tube (57) A reinforced cuffed tube 1 with a sealing cuff 13 at its patient end 12 has a helical reinforcement 30, preferably of metal wire, and a separate inflation line 31, preferably of plastic, wound helically in parallel with the wire and between its adjacent turns, both being embedded within the wall ofthe shaft 10 ofthe tube 1. The shaft 10 may extend beyond a neck flange 20 to a machine end connector 15. The reinforcement wire 30 continues between the flange 20 and the connector 15 but the inflation line 31 connects with an inflation tube 34 at the flange. The tube has application as a paediatric tracheostomy tube. The tube is manufactured by wrapping the reinforcement wire and the inflation line helically around the outside of a mandrel, then dipping in or overmoulding with silicone before removing the shaft from the mandrel with the wire and line embedded in the shaft wall.

FIG. 3

1/2

FIG. 1

2/2

FIG. 2

CUFFED TUBES

This invention relates to cuffed tubes and more particularly, but not exclusively, to tracheal tubes.

Tracheal tubes are used to enable ventilation, respiration or spontaneous breathing of a patient. Tracheostomy tubes are 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. Tracheostomy tubes can be inserted by different techniques, such as the surgical cut-down procedure carried out in an operating theatre or a cricothyroidotomy procedure, which may be carried out in emergency situations.

Tracheostomy tubes are generally used for more long-term ventilation or where it is not possible to insert an airway through the mouth or nose. The patient is often conscious while breathing through a tracheostomy tube, which may be open to atmosphere or connected by tubing to some form of ventilator. The tube is secured in position by means of a flange fixed with the machine end of the tube and positioned to extend outwardly on opposite sides of the tube. The anatomy of patients varies considerably according to age and build.

Tracheostomy tubes can be made of various materials and are usually of a bendable plastics material such as PVC, polyurethane or silicone. Silicone tubes are particularly advantageous for long-term use because they can be highly flexible, making them less traumatic and damaging to tissue contacted by the tube. The soft nature of silicone, however, means that they can be easily kinked and occluded by external pressure unless measures are taken to avoid this. Often, silicone tubes are reinforced by means of a stiff helical member extending along the tube. Typically, the reinforcement member is a metal wire.

Tracheostomy tubes are often also provided with an inflatable sealing cuff that is inflated around the tube towards its patient end in order to form a seal with the trachea so that gas is confined to flow along the bore of the tube. The sealing cuff is inflated via an inflation lumen extending along the tube. If the tube is reinforced, the inflation line cannot extend within the thickness of the wall of the tube so extends along the outside of the reinforcement wire. This leads to a protruding ridge extending along the length of the outside of the tube. The problem with this is that the protruding ridge interrupts the smooth outer surface of the tube and can cause discomfort or trauma to tissue in the region of the stoma. This can be a particular problem with tubes intended for paediatric and neonatal use.

It has been proposed in GB933307 to incorporate a helical inflation line within the thickness of the wall of the tube to serve the dual purposes of both enabling inflation gas to be supplied to the sealing cuff and acting as a helical reinforcement member. The problem with this arrangement is that, in order to achieve sufficient reinforcement the inflation line has to be wound with a very close pitch, leading to a large number of turns and a large overall length. This is particularly the case because the hollow nature of the reinforcement makes it weaker than a solid wire reinforcement and because the hollow structure of the inflation line means that it would be of a plastics material rather than a metal. The long length of the inflation line gives it a high resistance to gas flow along it, making it difficult to inflate and deflate the sealing cuff. This problem is even worse with tubes, such as those with a silicone cuff, that are inflated using a liquid.

It is an object of the present invention to provide an alternative cuffed medicosurgical tube.

According to one aspect of the present invention there is provided a cuffed tube including a shaft, an inflatable sealing cuff towards the patient end of the shaft and an inflation lumen extending along the shaft within its wall and opening at one end into the interior of the sealing cuff, the tube also including a helical reinforcement member extending along a part at least of the length of the shaft, and the inflation lumen extending along a part at least of the length of the shaft along a helical path parallel with the reinforcement member and between adjacent turns of the reinforcement member.

The shaft of the tube may be of a silicone material. The reinforcement member is preferably a metal wire. The inflation lumen may be provided by a plastics tube of a stiffer material than the main body of the shaft. The tube may include a flange by which the tube is attached with the patient, the flange being located along the shaft between its patient end and its machine end so that a region of the shaft extends between the flange and the machine end of the tube. The inflation lumen may extend helically only along that part of the length of the shaft between the flange and the sealing cuff.

According to another aspect of the present invention there is provided a paediatric tracheostomy tube according to the above one aspect of the present invention.

According to a further aspect of the present invention there is provided a method of manufacturing the shaft of a medico-surgical tube of the kind having an inflatable sealing cuff towards its patient end, comprising the steps of wrapping a reinforcement wire and an inflation line helically around the outside of a mandrel with the inflation line extending parallel to and between adjacent turns of the reinforcement wire, then dipping or overmoulding the reinforcement wire and inflation line with a silicone or other plastics and subsequently removing the shaft from the mandrel with its embedded reinforcement wire and inflation line.

According to yet another aspect of the present invention there is provided a shaft for a medico-surgical tube made according to the above further aspect of the present invention.

A tracheostomy tube and a method of manufacture of such a tube both according to the present invention will now be described, by way of example, wijth reference to the accompanying drawings in which:

Figure 1 is a perspective view of the tracheostomy tube;

Figure 2 is a cross-sectional, side elevation view of the tube; and

Figure 3 is an enlarged cross-sectional view of a part of the tube shown in Figure 2.

With reference first to Figures 1 and 2 the tracheostomy tube 1 is for use with paediatric patients and has a curved shaft 10 of circular section and with an outer diameter of around 4mm to 6mm for paediatric and neonatal patients. The shaft 10 has a patient end 12 adapted to be located within the trachea of the patient and has a conventional sealing cuff 13 towards its patient end. The cuff 13 shown is of a high pressure kind made of an elastic material that lies close to the shaft 10 when deflated and is stretched outwardly when inflated. 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 size, shape and material according to the application.

The machine end 14 of the shaft 10 is adapted, during use, to be located externally of the tracheostomy opening formed in the patient’s neck. The machine end 14 of the shaft 10 is bonded into a hub or connector 15 having a conventional 15mm male tapered outer surface 16. The connector 15 is adapted to make a removable push fit in a conventional 15mm 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 a location about two thirds the way along the shaft from its patient end 12. This leaves a region 3 about one third the length of the shaft 10 extending rearwardly from the flange 20 to the connector 15. 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.

Tubes having a length of flexible shaft between the flange and connector are known primarily in paediatric tubes so as to isolate the connector from the flange and thereby reduce forces applied to tissue around the stoma when a mating connector is connected to or disconnected from the connector.

With reference now also to Figure 3, the shaft 10 has a helical metal wire reinforcement member 30, such as of a stainless steel (such as MP35 alloy), embedded within the thickness of the wall of the shaft and extending along its entire length from its patient end 12 to its machine end 14. It is envisaged that in some cases it may be preferred for the reinforcement member 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. The shaft also includes an inflation line 31 in the form of an extruded plastics tube with an internal diameter of about 0.30mm and an outer diameter of about 0.40mm. The plastics from which the inflation line 31 is made is stiffer, that is, has a higher durometer, than the silicone material of the main body of the shaft 10 and has a higher melt temperature than the silicone so that the silicone can be overmoulded about the inflation line. The inflation line 31 extends helically along the shaft 10, being wound between the turns of the reinforcement wire 30 so that it extends parallel with the wire and with the same pitch. It can be seen that both the reinforcement wire 30 and the inflation line 31 can be embedded entirely within the thickness of the wall of the shaft 10 so that there is no projection on either the outer or inner surface of the shaft, thereby ensuring a smooth uninterrupted outer surface to the shaft.

The inflation line 31 does not extend along the entire length of the shaft 10 but terminates at its patient end 32 approximately midway along the length of the sealing cuff 13

Λ so that it is set back slightly from the patient end 12 of the shaft. The inflation line 31 also terminates at its machine end 33 on the patient side of the flange 20 before the machine end 14 of the shaft 10. The machine end 33 of the inflation line 31 is joined with the patient end of a small-bore inflation tube 34 extending freely outside the shaft 10, which passes through an opening 35 in the flange 20 and is terminated by a conventional combined inflation indicator and valve 36. The rear, machine end region 3 of the shaft 10, between the flange 20 and the connector 15 does not, therefore, include the helical inflation line 31. This arrangement ensures that the helical part of the overall inflation path (formed by the helical portion 31 and the inflation tube 34) is as short as possible, thereby limiting the overall length of the path and minimising the resistance to fluid flow along the path. However, if it were found easier to manufacture the shaft by having an inflation line extending helically along its entire length, it would still be possible to achieve the same aim of reduced resistance to flow by connecting the inflation tube to the inflation line at the flange, rather than at the machine end of the shaft. In this way, that portion of the inflation line extending along the region of the shaft between the flange and connector would not form a part of the actual inflation path but would be blocked at its patient end by the connection made with the inflation tube.

The shaft 10 could be made by wrapping the reinforcement wire 30 and the inflation line 31 helically around the outside of a mandrel and then dipping or overmoulding these components with the silicone or other plastics forming the main body of the shaft. The shaft is subsequently removed from the mandrel with its embedded reinforcement wire and inflation line.

I

In the arrangement of the present invention the main part of the reinforcement of the shaft against kinking and radial crushing forces is provided by the reinforcement wire 30. The strength of the wire 30 is such as to enable sufficient strength with a relatively large pitch of the helical winding. In this way, the pitch of the helical inflation line 31 is correspondingly relatively large so that fewer turns are required to cover the distance between the sealing cuff 13 and the flange 20. This reduces the overall length of the inflation path compared with what would be necessary to achieve a similar reinforcement strength using the inflation line by itself as the reinforcement. This reduction in length reduces the resistance to flow of fluid along the inflation path to inflate and deflate the sealing cuff. This is particularly important in tubes having a silicone sealing cuff because these are usually inflated with a liquid, such as saline, because the cuff is relatively porous to gases.

In the present invention, because the major part of the reinforcement is provided by the helical wire 30 it enables greater freedom in the choice of materials for both the reinforcement and the inflation line 31. It will be appreciated that, if the inflation line were made from a relatively hard plastics material, it would contribute a greater proportion of the reinforcement of the shaft thereby enabling the pitch of the helical wire and inflation line to be increased further.

The invention is particularly advantageous in paediatric size tubes because the small diameter shafts in such tubes makes them particularly prone to kinking and it is particularly important in such tubes for the outer surface to be as smooth as possible by avoiding any projection of the inflation line on the outer surface of the shaft.

Although the invention has particular advantages in tracheostomy tubes the invention could also be used in other reinforced, cuffed medico-surgical tubes.

Claims

1. A cuffed tube (1) including a shaft (10), an inflatable sealing cuff (13) towards the patient end (12) of the shaft and an inflation lumen (31) extending along the shaft within its wall and opening at one end (32) into the interior of the sealing cuff (13), wherein the tube (1) also includes a helical reinforcement member (30) extending along a part at least of the length of the shaft (10), and wherein the inflation lumen (31) extends along a part at least of the length of the shaft (10) along a helical path parallel with the reinforcement member (30) and between adjacent turns of the reinforcement member (30).

2. A tube according to Claim 1, wherein the shaft (10) of the tube (1) is of a silicone material.

3. A tube according to Claim 1 or 2, wherein the reinforcement member is a metal wire (30).

4. A tube according to any one of the preceding claims, wherein the inflation lumen is provided by a plastics tube (31) of a stiffer material than the main body of the shaft (10).

5. A tube according to any one of the preceding claims, wherein the tube includes a flange (20) by which the tube is attached with the patient, and wherein the flange (20) is located along the shaft (10) between its patient end (12) and its machine end (14) so that a region (3) of the shaft extends between the flange (20) and the machine end (14) of the tube.

6. A tube according to Claim 5, wherein the inflation lumen (31) extends helically only along that part of the length of the shaft (10) between the flange (20) and the sealing cuff (13).

7. A paediatric tracheostomy tube (1) according to any one of the preceding claims,

8. A paediatric tracheostomy tube (1) substantially as hereinbefore described with reference to the accompanying drawings.

9. A method of manufacturing the shaft (10) of a medico-surgical tube of the kind having an inflatable sealing cuff (13) towards its patient end (12), comprising the steps of wrapping a reinforcement wire (30) and an inflation line (31) helically around the outside of a mandrel with the inflation line extending parallel to and between adjacent turns of the reinforcement wire, then dipping or overmoulding the reinforcement wire and inflation line with a silicone or other plastics and subsequently removing the shaft (10) from the mandrel with its embedded reinforcement wire (30) and inflation line (31).

10. A shaft for a medico-surgical tube made by a method according to Claim 9.

11. A method of manufacturing a medico-surgical tube (1) substantially as hereinbefore described with reference to the accompanying drawings.

12. A tube made by a method according to Claim 11.

Intellectual

Property

Office

GB1708151.4

1-12