WO2016174379A1

WO2016174379A1 - Speaking valves and tracheostomy tube assemblies

Info

Publication number: WO2016174379A1
Application number: PCT/GB2016/000075
Authority: WO
Inventors: Timothy Bateman; Stephen James Field; Andrew Thomas Jeffrey; Christopher John WOOSNAM
Original assignee: Smiths Medical International Ltd
Current assignee: Smiths Medical International Ltd
Priority date: 2015-04-25
Filing date: 2016-04-08
Publication date: 2016-11-03
Anticipated expiration: 2017-10-25
Also published as: GB201507195D0

Abstract

A tracheostomy tube speaking valve (2) without any moving parts is formed with a Tesla valvular conduit of the kind having a flow passage (23) with a series of loops (26) and (27) the opposite ends of which are inclined towards the patient end (22) of the passage. This allows air to flow through the valve (2) preferentially from the machine end (21) to the patient end (22) to enable the patient to inhale but restricts flow in the opposite direction so that the major part of air exhaled by the patient is diverted to flow to the vocal folds. The length of the speaking valve (2) is contained entirely within the bore (18) of the tracheostomy tube (1).

Description

SPEAKING VALVES AND TRACHEOSTOMY TUBE ASSEMBLIES

This invention relates to speaking valves of the kind for tracheostomy tubes.

Tracheostomy tubes are used to ventilate patients during and after surgery. As the patient begins to recover, it is preferable for him to be gradually weaned off breathing through the tube before it is completely removed. Also, in order to enable the patient to speak it is necessary to allow at least a part of the air exhaled by the patient to flow up past the tracheostomy tube to the vocal folds instead of out through the machine end of the tube. Both these ends can be achieved by deflating or partially deflating the sealing cuff on the tube. Alternatively, a fenestrated tracheostomy tube can be used having one or more small openings in its side wall, so that a part of the patient's breathing passes through these openings and via his nose or mouth, instead of through the machine end of the tracheostomy tube.

An inner cannula is commonly used with tracheostomy tubes, being removably inserted in the outer, tracheostomy tube so that it can be removed and replaced periodically to ensure that the passage through the assembly does not become blocked by secretions. This avoids the need to remove the outer tube frequently. The inner cannula can also be used to block the openings in a fenestrated when speech is not required but must be removed from the tube when the patient wants to speak.

When the patient needs to speak it is common practice to fit a speaking valve onto the connector at the machine end of the tube. The speaking valve includes a one-way valve that enables air to be inhaled by the patient through the valve but prevents or limits flow out through the valve so that air instead flows to the larynx via the fenestrations or around the outside of a tube with a deflated cuff. The speaking valve includes a movable valve element such as a flexible flap, which is moved towards or away from a flow path through the valve, thereby preventing or enabling flow through the valve. Examples of speaking valves are described in, for example, US4325366, GB2164424, GB2214089, GB2313317, EP78685, EP214243, EP18461, DE2505123 and DE3503874. Tracheostomy tubes with speaking valves are used by conscious patients who may have to use such a tube permanently or long-term. Conventional speaking valves project from the machine end fitting of the tracheostomy tube so present a problem in that they tend to increase the profile of the tube and make it more conspicuous, which can be embarrassing for the patient. Another problem arises because conventional speaking valves may interfere with clothing around the neck region, which may cause uncomfortable pressure to be exerted on the tube itself.

It is an object of the present invention to provide an alternative speaking valve and a tracheostomy tube assembly including such a speaking valve.

According to one aspect of the present invention there is provided a speaking valve of the above-specified kind, characterised in that the speaking valve includes a tube arranged to extend along at least a part of the bore of a tracheostomy tube, and that the tube has a flow passage extending along it shaped to enable gas flow preferentially in one direction, into the patient, and to restrict gas flow in the opposite direction, out of the patient.

The flow passage preferably includes a series of loops the opposite ends of which are inclined towards the patient end of the flow passage. The flow passage is preferably provided by a Tesla valvular conduit. The interior of the speaking valve may include deformable portions that allow a cleaning tool to be passed along the flow passage inside of the valve. The speaking valve may be split longitudinally to enable it to be opened for cleaning. The speaking valve may be made by injection moulding or by casting on a core of a material that is subsequently removed by melting or dissolving.

According to another aspect of the present invention there is provided a

tracheostomy tube assembly including a tracheostomy tube and a speaking valve according to the above one aspect of the present invention extending along a part at least of the bore of the tube. The tube may have at least one fenestration in its wall positioned to allow air to flow to the vocal folds, the patient end of the speaking valve terminating on the machine side of the fenestration so that it does not block flow out through the fenestration.

According to a further aspect of the present invention there is provided a

tracheostomy tube assembly including a tracheostomy tube and a speaking valve, the length of the speaking valve being contained entirely within the bore of the tracheostomy tube.

According to yet another aspect of the present invention there is provided a tracheostomy tube assembly according to the above further aspect of the present invention, the speaking valve being of a kind according to the above one aspect of the present invention.

A tracheostomy tube assembly including a speaking valve 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 perspective view of the tracheostomy tube assembly and speaking valve;

Figure 2 is a cross sectional, side elevation view of the speaking valve showing flow into the patient; and

Figure 3 is an enlarged cross-sectional, side elevation view of the patient end of the speaking valve showing restricted flow out of the patient.

With reference first to Figure 1, the assembly comprises a tracheostomy tube 1 and a speaking valve 2 fitted in and extending along the tube and removable from its machine end 3.

The tracheostomy tube 1 includes a curved shaft 10 of a plastics material and having a circular cross-section. The tube extends from a patient end 11 to a neck flange 12 and a machine end fitting or coupling 13 of the conventional 15mm male tapered kind. A sealing member in the form of an inflatable cuff 14 encircles the shaft 10 towards the patient end 11. The interior of the cuff 14 communicates with an inflation line 15 including an inflation indicator in the form of a pilot balloon 16 having a sealing valve 17 at its machine end. In this example, the tube 1 does not have fenestrations, speech being enabled by deflating the cuff 14. Alternatively, the tube need not have a sealing cuff.

With reference now also to Figures 2 and 3, the speaking valve 2 consists of an inner cannula or tube 20 with an enlarged hub 21 at its machine end adapted to locate within the machine end coupling 13 on the tracheostomy tube 1. The hub 21 could protrude slightly from the machine end of the coupling 13 or have a ring-pull arrangement (not shown) to enable the valve to be grasped and pulled out of the tube 1 when necessary. The outside of the tube 20 is smooth, continuous and of circular section. The length of the speaking valve 2 is such that it extends as a close sliding fit along the entire length of the bore 18 of the tracheostomy tube 1 such that the patient end 22 of the valve is located at the patient end 11 of the tracheostomy tube 1.

The inside of the speaking valve 2, along the length of the tube 20, is specially shaped to provide a flow passage 23 that allows gas to flow more easily along the passage in one direction than in the opposite direction. More particularly, the flow passage 23 allows a ready flow of inspiratory air or other gas from the machine end 21 to the patient end 22, that is, into the patient and substantially (but not entirely) blocks flow in the opposite direction, that is, expiratory flow out of the patient. One example of such an arrangement is known as a "Tesla valvular conduit" and is described in US 1329559. The flow path 23 comprises a series of flow regions 24 one after the other (seven such regions are shown in Figure 2). Each flow region 24 has a central, axial passage 25 and two lateral loops 26 and 27 positioned one after the other. The opposite ends of each loop 26 and 27 open into the central passage 25 at an angle that is inclined in the direction of preferential flow, that is, towards the patient end 22 of the valve or cannula 2. The flow of air or other gas during inhalation is illustrated in Figure 2 where the arrows indicate that the gas can flow through the valve 2 relatively freely, along the central passage 25, thereby enabling the patient to inhale freely. The upstream end of the loops 26 and 27 are angled in the downstream direction such that there is little flow into these loops. Any flow there is into the upstream end of the loops 26 and 27 exits the downstream end of the loop in the same direction as the flow along the central passage 25, thereby contributing to the overall flow.

Figure 3, however, illustrates what happens when the patient tries to exhale through the valve 2. The expiratory gas is initially split along two divergent paths, one provided by the central passage 25 and the other by the inclined opening into the first, lower loop 26. The gas flowing along this loop 26 emerges from its opposite, downstream end at an angle directed back towards the patient end of the valve, that is, against the flow along the central passage 25, thereby impeding and reducing the overall flow from right to left out of the patient. The same effect is created at the next loop 27 and at each subsequent loop, thereby producing a progressive drop in pressure along the valve 2, with very little gas emerging from the machine end 21.

The valve 2 of the present invention does not need any moving parts so avoids the problem of such moving parts sticking or wearing during use. The length of the speaking valve 2 is contained entirely within the bore of the tracheostomy tube so avoids the problem of any part extending beyond the machine end fitting. This enables the profile of the external part of the tracheostomy assembly with the speaking valve to be very small, thereby avoiding the problem of conspicuous speaking valves or speaking valves that interfere with clothing. Long-term tracheostomy tubes often have a low profile fitting without the conventional 15mm male connector. Speaking valves according to the present invention are particularly suited to use with such tubes.

Because the speaking valve 2 of the present invention is provided as a part of an inner cannula 20 it serves the dual purpose of enabling speech and providing an inner cannula that can be removed and replaced regularly as secretions build up, without the need to replace the outer tracheostomy tube 1.

The tracheostomy tube assembly described above uses an unfenestrated tube 1 and relies on the tube being uncuffed or having its cuff 14 deflated so that exhaled air can flow past the tube to the larynx and vocal cords to enable speech. If a speaking valve according to the present invention were to extend along the entire length of a fenestrated tube it can be seen that it would block the openings or fenestrations and thereby prevent exhalation.

However, it would be possible for a speaking valve according to the present invention to be used with a fenestrated tube providing the valve were shorter and its patient end terminated above (on the machine side of) the fenestrations. The shorter length of such a valve would mean that it would have fewer divergent flow loops and would, therefore, make it less effective at blocking exhaled gas flow but it might still be sufficiently effective to enable speech.

The particular form of the Tesla flow passageway described above and illustrated is only exemplary since there could be other configurations of flow passageway that would have a similar effect of enabling inspiratory flow but restricting expiratory flow. In order to enable the flow passageway to be cleaned the loop formations could be deformable to enable a cleaning brush to be passed down the central passage. Alternatively, or additionally, the inner cannula/speaking valve could be of a clam type split construction with a longitudinal hinge along one side and clips along the opposite open side so that the valve could be opened by folding along the hinge to expose the interior flow passageway and more readily enable cleaning.

Speaking valves according to the present invention could be made in various different ways. For example, they could be moulded, such as by injection moulding. Alternatively, they could be cast about a core it the shape of the desired flow passage and the core subsequently removed such as by melting or dissolving. It would also be possible to use 3-D printing techniques to manufacture such valves.

Claims

1. A speaking valve for a tracheostomy tube, characterised in that the speaking valve (2) includes a tube (20) arranged to extend along at least a part of the bore (18) of a tracheostomy tube (1), and that the tube has a flow passage (23) extending along it shaped to enable gas flow preferentially in one direction, into the patient, and to restrict gas flow in the opposite direction, out of the patient.

2. A speaking valve according to Claim 1, characterised in that the flow passage (23) includes a series of loops (26 and 27) the opposite ends of which are inclined towards the patient end (22) of the flow passage (23).

3. A speaking valve according to Claim 1 or 2, characterised in that the flow passage (23) is provided by a Tesla valvular conduit.

4. A speaking valve according to any one of the preceding claims, characterised in that the interior of the speaking valve (2) includes deformable portions that allow a cleaning tool to be passed along the flow passage (23) inside of the valve.

5. A speaking valve according to any one of the preceding claims, characterised in that the speaking valve is split longitudinally to enable it to be opened for cleaning.

6. A speaking valve according to any one of the preceding claims, characterised in that the speaking valve is made by injection moulding.

7. A speaking valve according to any one of Claims 1 to 5, characterised in that the speaking valve is made by casting on a core of a material that is subsequently removed by melting or dissolving.

8. A tracheostomy tube assembly including a tracheostomy tube (1) and a speaking valve (2) according to any one of the preceding claims extending along a part at least of the bore (18) of the tube (1).

9. A tracheostomy tube assembly according to Claim 8, characterised in that the tube has at least one fenestration in its wall positioned to allow air to flow to the vocal folds, and that the patient end of the speaking valve terminates on the machine side of the fenestration so that it does not block flow out through the fenestration.

A tracheostomy tube assembly including a tracheostomy tube (1) and a speaking valve (2), characterised in that the length of the speaking valve (2) is contained entirely within the bore (18) of the tracheostomy tube (1).

11. A tracheostomy tube assembly according to Claim 10, characterised in that the

speaking valve (2) is of a kind according to any one of Claims 1 to 7.