GB2383756A

GB2383756A - A trachoestomy dilator assembly

Info

Publication number: GB2383756A
Application number: GB0225991A
Authority: GB
Inventors: Christopher Stratton Turnbull
Original assignee: Smiths Group PLC
Current assignee: Smiths Group PLC
Priority date: 2001-12-18
Filing date: 2002-11-06
Publication date: 2003-07-09
Anticipated expiration: 2022-11-06
Also published as: GB2383756B; GB0225991D0; CA2411656A1; GB0130156D0; DE10257000A1; US20030114871A1; JP2003190293A

Abstract

A percutaneous tracheostomy assembly comprises a dilator 2 mounted on a needle 1. The needle has a hollow metal shaft with a pointed tip 10 at one end and a hub 11 at its opposite end. The dilator 2 is of plastics with a narrow, flexible patient end portion 20, a tapering intermediate portion 21 and a substantially rigid, wider rear portion 22. The tip 10 of the needle 1 projects from the patient end 20 of the dilator 2 when the needle hub 11 abuts the rear end of the dilator so that the patient end of the assembly can be pushed into the trachea 32. The length of the patient end portion 20 of the dilator 2 is such that the tip 10 of the needle 1 is spaced from the posterior wall 33 of the trachea 32 when the tapered portion 21 of the dilator abuts the surface of the skin 31. After insertion, the needle 1 is replaced with a guidewire 40 so that the dilator 2 can be pushed in further to expand the opening.

Description

MEDICO-SURGICAL APPARATUS

This invention relates to medico-surgical apparatus.

One technique for performing a percutaneous tracheostomy involves a needle carrying a cannula. An initial cut is made with a scalpel through the skin of the neck and the needle is pushed through neck tissues and the anterior wall of the trachea so that the tip of the needle and the cannula locate in the trachea. The needle is then pulled out to leave the cannula in place. A guidewire is inserted through the cannula, which is then removed. A first dilator or pre-dilator is slid along the guidewire to expand the opening through the tissue slightly to between 4-5mm, sufficient to enable a larger dilator to be inserted. The first dilator is typically Scm long, it is straight and relatively rigid. The opening is then expanded with the larger dilator or with subsequent, progressively larger dilators until it is large enough to receive a percutaneous tracheostomy tube.

One problem with this technique is that there is a risk the first dilator will be pushed in too far and contact the posterior wall of the trachea, causing damage. This problem is made worse because the cartilagenous anterior wall of the trachea presents a high resistance to penetration and, once the dilator has passed through this the resistance drops suddenly with the risk that dilator will move forwardly rapidly. Also, there is a greater risk of contact with the posterior wall of the trachea because the force applied by the dilator tends to push the anterior wall of the leaches towards the posterior wall, reducing the gap between them.

It is an object of the present invention to provide alternative medicosurgical apparatus. According to one aspect of the present invention there is provided a tracheostomy dilator adapted for insertion through tissue into the trachea on a needle, the dilator having a bore extending therethrough to receive the needle, a first, patient end portion and a second portion extending rearwardly from the first portion, the first portion being flexible and of substantially constant external diameter, and the second portion being more rigid and tapering along at least a part of its length to a larger diameter towards its rear end.

The length of the first portion is preferably such that when the forward end of the second portion abuts the surface of the neck the tip of the first portion is located within the trachea spaced from the posterior wall. The first portion may be substantially 20rnm long and have an external diameter of substantially 2mrn. The second portion preferably tapers to a diameter of about 4.6mm at its rear end and tapers along a distance of substantially 1 5mm.

The dilator preferably includes a rear end portion extending from the second portion and having a substantially constant external diameter. The dilator is preferably moulded of a plastics material.

According to another aspect of the present invention there is provided a tracheostomy assembly of a needle and a dilator removably mounted on the needle, the dilator having a bore extending therethrough along which the needle extends, a first, patient end portion and a second portion extending rearwardly from the first portion, the first portion being flexible and

of substantially constant external diameter, and the second portion being more rigid and tapering along at least a part of its length to a larger diameter towards its rear end.

The assembly is preferably straight. The needle preferably has a pointed tip at its patient end and a hub at its rear end, the tip projecting beyond the patient end of the dilator and the hub engaging the rear end of the dilator. The assembly is preferably arranged such that when the forward end of the second portion of the dilator abuts the surface of the neck the tip of the needle is located within the trachea spaced from the posterior wall. The assembly may include a guidewire that is insertable in the dilator after removal of the needle.

A percutaneous tracheostomy assembly including a dilator according to the present invention, will now be described, by way of example, with reference to the accompanying drawing, in which: Figure 1 is a crosssectional side elevation view of the assembly; and Figures 2 to 5 are partly sectional side elevation views showing the assembly and dilator in use.

With reference first to Figure 1, the assembly includes a needle 1 and a dilator 2.

The needle 1 is hollow and of metal, with a pointed penetrating tip 10 at one end and a moulded hub 11 at its opposite end.

The dilator 2 is tubular and of plastics material. The dilator has a flexible forward, patient end portion 20 that is about 20mm long and has a constant external diameter of about 2mm along its length. A second, intermediate portion 21 extends from the rear of the forward end portion 20 and is about 15mm long. The intermediate portion 21 tapers outwardly along its length from a diameter of 2mm at its forward end to a diameter of 4.6mm at its rear end.

This intermediate portion 21 is substantially rigid. The rear, machine end portion 22 of the dilator 2 has a constant diameter of 4.6mm and extends for a distance of about 40mm; this also is substantially rigid. A bore 23 extends coaxially along the entire length of the dilator 2.

The total length of the dilator 2 is such that, when fitted on the needle 1, the rear end of the dilator abuts the hub 11 of the needle and its tip 10 is exposed at the forward end of the dilator. Figures 2 to 5 show how the assembly is used. First, as shown in Figure 2, the assembly is pushed through the neck tissue 30, after having first made a cut through the skin 31, until the tip 10 of the needle 1 and the patient end of the dilator locate in the trachea 32.

Penetration of the trachea could be detected in a conventional manner, such as by aspirating air with a syringe connected to the hub 11. The length of the patient end portion 20 of the dilator 2 is such that when the forward end of the intermediate portion 21 abuts the skin 31, the tip of the assembly is located in the trachea spaced from the posterior wall. The taper on the intermediate portion 21 increases the resistance to insertion of the assembly and helps reduce the risk of the assembly being inserted too far and damaging the posterior wall 33 of the trachea 32. Next, as shown in Figure 3, the needle 1 is removed, leaving the dilator 2 in position. Then the user inserts a guidewire 40 through the bore 23 of the dilator 2, as shown

s in Figure 4, so that its forward end 41 projects from the dilator within the trachea 32. The user then grips the rear end 22 of the dilator 2 and pushes it in along the guidewire 40, as shown in Figure 5. As the intermediate portion 21 enters the neck tissue 30 it starts to expand the opening 34 through the tissue from 2mm to 4.6mm. The dilator 2 is pushed in until the intermediate portion 21 lies within the trachea 32 and the rear portion 22 is located in the neck tissue 30. This operation can be performed smoothly in a controlled manner because the tip of the dilator 2 has already penetrated the stiff cartilagenous front wall of the trachea 32.

The flexible forward portion 20 of the dilator 2 is guided by the guidewire and prevents any damage to the posterior wall 33 of the trachea 32. The dilator 2 is then pulled out, leaving the guidewire 40 in position and subsequent dilators (not shown) are inserted along it in the usual way until the opening 34 to the trachea 32 is large enough to receive a percutaneous tracheostomy tube.

The present invention enables the risk of damage to the posterior wall of the trachea to be reduced. The invention also simplifies the formation of a tracheostomy by reducing the number of steps. Because a single component is used there is no need for a separate cannula to be removed before a pre-dilator can be inserted. The term "tracheostomy" is used to denote any opening providing access to the trachea including in the cricothyroid region.

The dilator of the invention could be modified for use with a pre-dilator by shortening the patient end tip of the dilator and reducing the maximum diameter of the intermediate portion to about 3mm. Such an arrangement would still reduce the risk of drainage to the posterior wall of the trachea by the subsequently-inserted pre-dilator because its entry would be made easier by the larger size opening.

The patient end portion 20 of the dilator 2 could be formed such that it bends preferentially in one direction so that this can be directed caudally. Preferential bending could be achieved by means of a stripe of a different material having a different hardness, or by altering the wall thickness.

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Claims

1. A tracheostomy dilator adapted for insertion through tissue into the trachea on a needle, wherein the dilator has a bore extending therethrough to receive the needle, a first, patient end portion and a second portion extending rearwardly from the first portion, wherein the first portion is flexible and of substantially constant external diameter, and wherein the second portion is more rigid and tapers along at least a part of its length to a larger diameter towards its rear end.

2. A dilator according to Claim 1, wherein the length ofthe first portion is such that

when the forward end of the second portion abuts the surface of the neck the tip of the first portion is located within the trachea spaced from the posterior wall.

3. A dilator according to Claim 1 or 2, wherein the first portion is substantially 20m n long.

4. A dilator according to any one of the preceding claims, wherein the external diameter of the first portion is substantially 2rnm.

5. A dilator according to any one of the preceding claims, wherein the second portion tapers to a diameter of about 4.6mm at its rear end.

6. A dilator according to any one of the preceding claims, wherein the second portion tapers along a distance of substantially 15mm.

7. A dilator according to any one of the preceding claims, wherein the dilator includes a rear end portion extending from the second portion and having a substantially constant external diameter.

8. A dilator according to any one of the preceding claims, wherein the dilator is moulded of a plastics material.

9. A dilator substantially as hereinbefore described with reference to the accompanying drawings.

10. A trach,eostomy assembly of a needle and a dilator removably mounted on the needle, wherein the dilator has a bore extending therethrough along which the needle extends, a first, patient end portion and a second portion extending rearwardly from the first portions wherein the first portion is flexible and of substantially constant external diameter, and wherein the second portion is more rigid and tapers along at least a part of its length to a larger diameter towards its rear end.

11. An assembly according to Claim 10, wherein the assembly is straight.

12. An assembly according to Claim 10 or 11, wherein the needle has a pointed tip at its patient end and a hub at its rear end, wherein the tip projects beyond the patient end of the dilator, and wherein the hub engages the rear end of the dilator.

13. An assembly according to any one of Claims 10 to 12, wherein the assembly is arranged such that when the forward end of the second portion of the dilator abuts the surface of the neck the tip of the needle is located within the trachea spaced from the posterior wall.

14. An assembly according to any one of Claims 10 to 13 including a guidewire that is insertable in the dilator after removal of the needle.

15. An assembly substantially as hereinbefore described with reference to the accompanying drawings.

16. Any novel and inventive feature or combination of features as hereinbefore described.