WO2008009947A1

WO2008009947A1 - Tracheal tubes

Info

Publication number: WO2008009947A1
Application number: PCT/GB2007/002742
Authority: WO
Inventors: Neil Adam Tookman
Original assignee: Smiths Group Plc
Priority date: 2006-07-20
Filing date: 2007-07-19
Publication date: 2008-01-24
Also published as: GB0614362D0

Abstract

An endotracheal tube is sealed with the inside of the trachea by means of several flexible sealing discs (11 to 14) spaced from one another along the tube shaft (1) towards its patient end (4). The discs (11 to 14) are each dished with a concave recess (16) on their rear side and also have a radial slit (17) to allow expansion and contraction. A suction lumen (20) extending along the shaft (1) opens via an opening (21) located in the recess (16) of the uppermost disc (11) so that secretions collecting above the disc can be removed.

Description

TRACHEAL TUBES

This invention relates to tracheal tubes of the kind having a tubular shaft and a plurality of outwardly-extending sealing discs mounted with the shaft one above the other towards the patient end.

Tracheal tubes are arranged to provide a passage for ventilation gas to and from a patient. The patient end of the tube is inserted in the trachea and the other, machine end protrudes from the body, that is, from the mouth in the case of an endotracheal tube or from a stoma in the neck in the case of a tracheostomy tube. Usually, the tube is provided with sealing means towards its patient end in the form of an inflatable cuff. The purpose of this cuff is to seal the outside of the tube with the inside of the trachea in order to confine gas to flow along the bore of the tube and to prevent gas flow between the outside of the tube and the wall of the trachea. There can be problems with inflatable cuffs. The cuff may leak or be under-inflated and provide an incomplete seal. The cuff may be over-inflated and cause trauma to the lining of the trachea. Over-inflation may be caused by permeation of anaesthetic gases, such as nitrous oxide, through the wall of the cuff. The cuff needs to be monitored during use to ensure that the cuff pressure is optimal but this may not be easy to do. The sealing cuff may crease or deform when inflated and form passages along which secretions that collect above the cuff can seep past the cuff into the lungs. Secretions that do enter the lungs can give rise to pneumonia infections.

Instead of an inflatable cuff, it has been proposed to provide several flexible discs or flanges on the tube, such as described in US3659611, US5322062, US5429127 and US5537729. The discs are mounted concentrically on the tube spaced one above the other towards the patient end and are selected such that the outer edge of the discs contacts the tracheal wall. Discs of this kind avoid some of the problems of inflatable cuffs. One problem, however, with such discs is that it may be difficult to prevent secretions that collect in the trachea above the discs from seeping past the discs and into the lungs. This is a particular problem where the discs are formed with radial slits to increase flexibility. It is an object of the present invention to provide an alternative tracheal tube.

According to the present invention there is provided a tracheal tube of the above- specified kind, characterised in that the tube includes a suction lumen extending rearwardly along the shaft from an opening closely adjacent the rear side of at least one of the discs such that secretions collecting above that disc can be removed by applying suction to the lumen.

Preferably the disc adjacent the suction opening is the uppermost disc closest to the machine end of the tube. Each disc is preferably dished to form a concave recess on its rear side. The or each suction opening is preferably located within the concave recess of a respective disc. The tube may include a plurality of suction openings adjacent the rear side of respective sealing discs. The sealing discs are preferably arranged to fold rearwardly along the shaft during insertion of the tube into the trachea and to fold forwardly, in the opposite direction, when the tube is removed from the trachea. The sealing discs may each have a radial slit extending to their outer edge to enable the discs to expand and contract. The suction lumen preferably extends within the thickness of the wall of the shaft. The tube may be an endotracheal tube.

An endotracheal tube 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 side elevation view of the tube;

Figure 2 is a perspective view of the patient end of the tube;

Figure 3 is a cross-sectional view of the tube along the line III-III of Figure 1;

Figure 4 is a side elevation view of the patient end of the tube with the discs folded back during insertion of the tube; and Figure 5 is a side elevation view of the patient end of the tube with the discs folded forwards during removal of the tube.

With reference first to Figures 1 to 3, the endotracheal tube includes a tubular shaft 1 of circular section made of a bendable plastics material such as PVC and curved along its length. At its rear or machine end 2, the shaft 1 is terminated with a coupling 3 adapted to connect with a cooperating coupling on tubing extending from a ventilation machine, resuscitator or the like. Where the patient is breathing spontaneously the machine end 2 may be left open. The forward or patient end 4 is bevelled at an angle of about 45°. The length and diameter of the shaft 1 differs from tube to tube according to the size and build of the patient on which the tube is to be used.

Instead of the usual inflatable sealing cuff, the tube has sealing means close to the patient end 4 in the form of four resilient, flexible discs 11 to 14. The discs 11 to 14 are circular, having a central circular aperture 15 bonded to the outside of the shaft 1 so that the discs extend outwardly of the shaft. In their natural state, the discs 11 to 14 each adopt a dished shape forming a rearwardly-facing concave recess 16. The external diameter of the discs 11 to 14 is about three times the external diameter of the shaft 1. Each disc 11 to 14 has a radial slit or cut 17 extending from its outer edge 18 radially inwardly to a point close to the central aperture 15. The slit 17 enables each disc to expand and retract. The discs 11 to 14 are equally spaced from one another along the length of the shaft 1, the spacing between adjacent discs being less than the radial width of the discs, that is, the radial distance between the central aperture 15 and the outer edge 18 of the disc. It will be appreciated that the present invention is not confined to tubes with four discs but that any number of two or more discs could be used.

The tube also has a suction lumen 20 extruded within the thickness of the wall of the shaft 1 and extending along the shaft on the outside of its curve. The suction lumen 20 is closed at the patient end tip 4 of the shaft 1 but opens externally via a suction opening 21 cut through the outer wall of the shaft just above the upper, or rearmost ones of the discs 11, that is, within the recess 16 formed on the upper side of the disc. The rear end of the suction lumen 20 is also closed, at the machine end 2 of the shaft 1, connection being made to the lumen by a small-bore suction tube 22 joined into the suction lumen via an opening cut into the suction lumen from outside the shaft, about halfway along the length of the tube. The rear end of the suction tube 22 is terminated by a closable or valved coupling 23 by which a suction source, such as a syringe (not shown), can be connected to the suction tube.

The tube is inserted through the mouth in the usual way. The forward movement and contact with patient tissue deflects the discs 11 to 14 rearwardly so that they overlap one another in the manner shown in Figure 4. When correctly positioned, the resilient nature of the discs 11 to 14 causes them to open outwardly to the configuration shown in Figure 2. In this position, the outer edge 18 of each disc 11 to 14 expands to contact and seal with the tracheal wall. Any secretions that form in the trachea above the discs 11 to 14 collect on the uppermost disc 11, in its recess 16. These secretions are periodically removed by applying suction to the rear end 23 of the suction tube 22 so that the secretions are sucked from the recess 16, through the opening 21, along the suction lumen 20 and into the suction tube for disposal.

Any secretions that might seep past the upper disc 11, such as via its slit 17, will be collected in the recess 16 of the adjacent disc 12. Further seepage will be collected by the other discs 13 and 14 so that very little will leak past all four discs. However, to reduce even further any leakage of secretions into the lungs, the tube could be provided with one or more additional suction openings positioned just above each of the other discs 12, 13 and 14. Each additional suction opening would preferably open into its own suction lumen. Figure 2 shows, in broken lines, an example of a tube with three further suction openings 21% 21" and 21'" one above each of the other discs. Although it is preferable for the suction opening of a tube having just one suction opening to be located above the rear or uppermost disc 11, it is not essential since secretions could be collected via an opening above a lower one of the discs. The suction lumen or lumens need not be formed within the wall of the shaft but could be provided by a separate tube or tubes attached to the outside of the shaft in some way, such as in a channel formed in the outer wall of the shaft, the suction opening being provided by an open end of the or each tube. When it is necessary to remove the tube from the patient, the machine end 2 of the tube is grasped and pulled rearwardly. This causes the sealing discs 11 to 14 to fold forwardly in the manner shown in Figure 5 so that the tube can be withdrawn without trauma to patient tissue.

It will be appreciated that the invention could alternatively be used on tracheostomy tubes.

Claims

1. A tracheal tube having a tubular shaft (1) and a plurality of outwardly-extending sealing discs (11 to 14) mounted with the shaft one above the other towards the patient end, characterised in that the tube includes a suction lumen (20) extending rearwardly along the shaft (1) from an opening (21, 21', 21", 21'") closely adjacent the rear side of at least one of the discs (11 to 14) such that secretions collecting above that disc can be removed by applying suction to the lumen (20).

2. A tracheal tube according to Claim 1, characterised in that the disc adjacent the suction opening is the uppermost disc (11) closest to the machine end (2) of the tube.

3. A tracheal tube according to any one of the preceding claims, characterised in that each disc (11 to 14) is dished to form a concave recess (16) on its rear side.

4. A tracheal tube according to Claim 3, characterised in that the or each suction opening (21, 21', 21", 21'") is located within the concave recess (16) of a respective disc.

5. A tracheal tube according to any one of the preceding claims, characterised in that the tube includes a plurality of suction openings (21, 21', 21", 21"') adjacent the rear side of respective sealing discs (11 to 14).

6. A tracheal tube according to any one of the preceding claims, characterised in that the sealing discs (11 to 14) are arranged to fold rearwardly along the shaft (1) during insertion of the tube into the trachea and to fold forwardly, in the opposite direction, when the tube is removed from the trachea.

7. A tracheal tube according to any one of the preceding claims, characterised in that the sealing discs (11 to 14) each have a radial slit (17) extending to their outer edge (18) to enable the discs to expand and contract.

8. A tracheal tube according to any one of the preceding claims, characterised in that the suction lumen (20) extends within the thickness of the wall of the shaft (1).

9. A tracheal tube according to any one of the preceding claims, characterised in that the tube is an endotracheal tube.