Patent Description:
Tracheal tubes are used to enable ventilation, respiration or spontaneous breathing of a patient. Endotracheal tubes are inserted via the mouth or nose so that one end locates in the trachea and the other end locates outside the patient. Tracheostomy tubes are inserted into the trachea via a surgically-formed opening in the neck. 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.

Tracheal tubes often have a sealing cuff on their outside close to the patient end. This usually takes the form of a cuff that is inflated by a gas or liquid so that, when inflated, it forms a seal with the tracheal wall, confining gas flow along the bore of the tube and preventing flow around its outside. The cuff is usually inflated and deflated by means of an inflation line in the form of a small-bore tube opening into the cuff at its patient end and extending along a channel along the outside of the shaft of the tube. The machine end of the inflation line extends freely beyond the channel and is terminated by a combined inflation indicator, connector and valve. Alternatively, the tracheal tube may have an inflation lumen extending within the wall of the shaft of the tube and joined towards the machine end of the shaft with a separate small-bore inflation tube. The nose of a syringe or the like is inserted in the connector, opening the valve so that inflation gas or liquid can be supplied to or from the sealing cuff via the inflation line. The inflation indicator usually takes the form of a small flexible envelope or balloon connected at one end with the connector. The inflation line extends and opens into the interior of the inflation indicator so that the indicator is inflated by pressure in the sealing cuff and inflation line. If the pressure in the sealing cuff should fall this would be indicated by a corresponding deflation of the inflation indicator.

A problem occurs when tracheostomy tubes with such indicators are used with children. The soft nature of the inflation indicator and the proximity of the inflation indicator to the child's mouth means that the indicator can be easily chewed or bitten. This is a problem because, if the indicator or inflation line should be damaged, it may permit the inflation gas or liquid to escape thereby allowing the sealing cuff to deflate. This could allow ventilation gas to pass around the outside of the tracheostomy tube and prevent correct ventilation of the patient. The child chewing the inflation line and indicator may also ingest a part of the indicator.

Tracheal tubes with inflatable sealing cuffs and inflation indicators having a protective enclosure, according to the preamble of claim <NUM>, are described in <CIT>,.

<CIT>, <CIT>, <CIT>, <CIT>, <CIT>, and <CIT>. <CIT> discloses an endotracheal tube with an inflatable sealing cuff and an inflation indicator having a protective enclosure.

It is an object of the present invention to provide an alternative tracheostomy tube assembly.

According to the present invention there is provided a tracheostomy tube assembly according to claim <NUM>, and a method according to claim <NUM>. The dependent claims define embodiments of the invention.

A paediatric tracheostomy tube assembly according to the invention as claimed, with an inflation indicator and protector, will now be described, by way of example, with reference to the accompanying drawings in which:.

With reference first to <FIG>, the assembly includes a tracheostomy tube <NUM> of a paediatric size having a curved shaft <NUM> of circular section and with an inner diameter of around <NUM>. The shaft <NUM> has a patient end <NUM> adapted to be located within the trachea of the patient and has a conventional sealing cuff <NUM> towards its patient end. The cuff <NUM> shown is of a high pressure kind made of an elastic material that lies close to the shaft <NUM> when deflated and is stretched outwardly when inflated. The shaft <NUM> and cuff <NUM> 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.

The machine end <NUM> of the shaft <NUM> is adapted, during use, to be located externally of the tracheostomy opening formed in the patient's neck. The machine end <NUM> of the shaft <NUM> is bonded into a hub or connector <NUM> having a conventional <NUM> male tapered outer surface <NUM>. The connector <NUM> is adapted to make a removable push fit in a conventional <NUM> 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 <NUM> could be left open to atmosphere when the patient is breathing spontaneously. The tracheostomy tube <NUM> also includes a radially-extending support flange <NUM> adapted to lie against the skin surface of the neck on either side of the tracheostomy stoma. The flange <NUM> is moulded integrally as one part with the shaft <NUM> at its machine end <NUM> or may be formed separately. The flange <NUM> has openings <NUM> at opposite ends for attachment to a neck strap (not shown) used to support the tube with the patient's neck.

The shaft <NUM> also includes an inflation line <NUM> in the form of a small-bore tube secured in a channel <NUM> extending along the outside of one side of the shaft. The inflation line <NUM> has an opening <NUM> towards its patient end located approximately midway along the length of the sealing cuff <NUM>. The machine end of the inflation line <NUM> extends through the flange <NUM> and continues unattached with the shaft <NUM> being joined with and extending into one end <NUM> a conventional inflation indicator <NUM>. The inflation indicator <NUM> includes a flat, flexible envelope or balloon <NUM> into which the inflation line <NUM> opens so that the balloon is inflated or deflated according to the inflation state of the sealing cuff <NUM>. The opposite end of the inflation indicator balloon <NUM> is bonded to one end of the outside of a rigid connector sleeve <NUM> containing a valve (not visible in the drawing) and being open at its machine end <NUM> to receive a male coupling such as the nose of an inflation syringe.

As so far described the tracheostomy tube assembly is conventional. The assembly differs from conventional tracheostomy tubes by the addition of a protector enclosure <NUM> adapted to extend around and enclose the inflation indicator <NUM> to protect it from damage by chewing.

<FIG> show the inflation indicator <NUM> before and after assembly of the protector enclosure <NUM> onto the inflation indicator <NUM>. The enclosure <NUM> consists of two main parts. The first, machine-end part or base <NUM> is a moulding of a semi-rigid, opaque plastics material, such as having a Shore D hardness of about <NUM>. The base <NUM> has a circular section with a waisted central region <NUM> formed with flats <NUM> around its circumference to improve the grip on the enclosure <NUM> between finger and thumb. The machine end <NUM> of the base <NUM> is open so that the machine end <NUM> of the inflation indicator <NUM> is accessible for inflation or deflation. At its opposite, patient end <NUM> the outer surface of the base <NUM> is formed with two opposite locking formations or notches <NUM> and <NUM>.

The protector enclosure <NUM> is completed by a second part <NUM> in the form of a transparent cylindrical sleeve. The sleeve <NUM> is moulded of a stiff, transparent plastics material and is circular in section with an open machine end <NUM> having an outwardly projecting annular rim <NUM> the external diameter of which is such that it snaps into an internal retaining groove (not shown) around the inside of the base <NUM>. The patient end <NUM> of the sleeve <NUM> is closed apart from a small opening <NUM> just large enough to receive the inflation line <NUM>. The sleeve <NUM> also has two diametrically opposite slots <NUM> and <NUM> extending longitudinally of the sleeve. One slot <NUM> opens at its machine end into the open machine end <NUM> of the sleeve <NUM> and opens at its opposite end into the small patient-end opening <NUM> of the sleeve. The other slot <NUM> is shorter and terminates before the machine end opening <NUM> and the patient end opening <NUM>. The longer slot <NUM> enables the sleeve <NUM> to be slid onto the inflation line <NUM> sideways and also gives the sleeve some resilience so that it can be squeezed to reduce the diameter at its machine end <NUM> and enable this to be inserted into the patient end of the base <NUM>. The sleeve <NUM> also has two locking features <NUM> and <NUM> on opposite sides of its outer surface, midway between the two slots <NUM> and <NUM> and about half way along the length of the sleeve. The locking features <NUM> and <NUM> are shaped to clip onto the two notches <NUM> and <NUM> on outside of the base <NUM>. Engagement of the locking features <NUM> and <NUM> on the sleeve <NUM> with the notches <NUM> and <NUM> on the base <NUM> prevents the sleeve rotating relative to the base.

The protective enclosure <NUM> could be permanently fitted onto the inflation indicator <NUM> by applying a bonding agent to the machine end of the sleeve <NUM> so that it becomes securely and permanently bonded to the base part <NUM>. Alternatively, the sleeve <NUM> need not be bonded to the base <NUM> so that the protector <NUM> can be removed from the inflation indicator <NUM> when necessary.

The protector enclosure <NUM> is fitted on the inflation indicator <NUM> by first sliding the inflation line <NUM> sideways through the long slot <NUM> of the sleeve <NUM> at a location spaced a short distance away from the inflation balloon. The sleeve <NUM> is then oriented so that the opposite slots <NUM> and <NUM> align with the edges of the inflation balloon <NUM>. The sleeve <NUM> can then be threaded rearwardly along the inflation line <NUM> and along the outside of the inflation indicator <NUM> as far as it will go. The assembly of the inflation indicator <NUM> and sleeve <NUM> is then slid rearwardly into the patient end of the base <NUM>, aligning the locking features <NUM> and <NUM> on the sleeve with the notches on the base. The sleeve <NUM> is squeezed at the same time to compress the slots <NUM> and <NUM> so as to enable the rim <NUM> to enter the base <NUM> and then open into the internal retaining groove when released. Instead of loading the sleeve <NUM> onto the inflation indicator <NUM> first it would be possible to insert the inflation indicator into the base first and then slide the sleeve over and along the inflation indicator into the base.

With the inflation indicator <NUM> contained within the protective enclosure <NUM> the balloon <NUM> can inflate and deflate in the usual manner and the state of inflation of the indicator can be viewed through the transparent sleeve <NUM>. If the child patient should chew on the assembly, the inflation indicator <NUM> will not be damaged because it is protected by the protector <NUM>.

The protector <NUM> can be readily fitted to a conventional inflation indicator of a tracheostomy tube without the need for any special tools. The protector could be provided separately of the tracheostomy tube and assembled on the inflation indicator by the user, if needed. The protector need not be fitted by a clinical specialist but can be fitted by a child's carer at home as needed.

Claim 1:
A tracheostomy tube assembly including a tracheostomy tube (<NUM>) having a shaft (<NUM>) with an inflatable sealing cuff (<NUM>) towards its patient end (<NUM>) and an inflation line (<NUM>) communicating with the sealing cuff (<NUM>) and having an inflation indicator (<NUM>) towards its machine end, wherein the assembly also includes a protective enclosure (<NUM>, <NUM>) extending around and enclosing the inflation indicator to protect it from damage by chewing, wherein the protective enclosure (<NUM>, <NUM>) is transparent, at least in part, to enable the inflation indicator (<NUM>) to be viewed through the enclosure, wherein the protective enclosure (<NUM>, <NUM>) has a first part (<NUM>) arranged to receive a machine end (<NUM>) of the inflation indicator (<NUM>) and a second part having a transparent sleeve (<NUM>) adapted to extend around the inflation indicator (<NUM>) and fit with the first part (<NUM>), wherein the second part (<NUM>) is open at its machine end (<NUM>) that fits with the first part (<NUM>), and wherein the second part (<NUM>) has an opening (<NUM>) at its patient end through which the inflation line (<NUM>) extends, and characterised in that the second part (<NUM>) has a slot (<NUM>) extending along its length between the open machine end (<NUM>) and the opening (<NUM>) at the patient end so that the inflation line (<NUM>) can be threaded through the slot (<NUM>).