GB2174303A

GB2174303A - Inflation indicator for cuffed catheter

Info

Publication number: GB2174303A
Application number: GB08609039A
Authority: GB
Inventors: Michael Norman Collins; Joseph Patrick Taylor
Original assignee: Smiths Group PLC
Current assignee: Smiths Group PLC
Priority date: 1985-04-26
Filing date: 1986-04-14
Publication date: 1986-11-05
Also published as: GB2174303B; GB8609039D0; JPS61259677A; DE3612198C2; FR2581188B1; GB8510646D0; DE3612198A1; JPH0425820B2; FR2581188A1

Abstract

An inflation indicator 20 for a cuffed tracheal tube has a balloon 22 and a female luer connector 24 that are formed integrally as a one-piece moulding of a thermoplastic material such as PVC. The wall thickness of the balloon is preferably between 0.08 mm and 0.15 mm whereas the wall thickness of the connector is between 1.0 mm and 2.0 mm. A tubular extension 28 joins the balloon 22 with the connector, the wall thickness of this extension being between that of the balloon and that of the connector. The inflation indicator may be made as an injection blow moulding or a dip blow moulding. <IMAGE>

Description

SPECIFICATION Inflation indicators This invention relates to inflation indicators.

The invention is more particularly concerned with inflation indicators for use on cuffed medicosurgical tubes.

Some medico-surgical tubes, such as endotracheal and tracheostomy tubes, have an inflatable cuff encircling their distal end which can be inflated to seal the tube to the inner wall of the body passage, in which they are inserted. The cuff is inflated by pumping a volume of gas into it, via a small bore lumen that extends along the tube within the thickness of the tube wall and that is coupled to a small-bore tube close to the machine end of the tube. A connector and inflation indicator are mounted at the machine end of the small-bore tube, the connector being used to couple the small-bore tube to the nose of a syringe or similar device by which gas is pumped into the cuff. The inflation indicator may take different forms but commonly comprises a balloon of flexible material that is connected at one end to the connector and at its other end to the small-bore tube.When the cuff is inflated, the pressure within the cuff is communicated via the small-bore tube and lumen to inflate the balloon. Examination of the balloon thereby enables the user to determine whether or not the cuff is inflated.

The balloon must be thin enough and made from a material that is sufficiently deformable to ensure that the balloon is deflected significantly by the pressure in the cuff. The connector must be made from a thicker, stiffer material to ensure that the nose of the syringe makes a secure connection and can be sealed, after inflation of the cuff, by means of a plug. Heretofore, the connector and balloon have therefore been made separately and have been assembled together after manufacture. This assembly operation is time consuming and must be performed accurately since it is important to achieve an effective seal in order to prevent loss of pressure and consequent deflation of the cuff. The flexible nature of the balloon material makes it difficult to produce this seal reliably.

It is an object of the present invention to provide an inflation indicator that can be used to avoid these difficulties.

According to one aspect of the present invention there is provided an inflation indicator for a cuffed medico-surgical tube, the indicator including a balloon that is inflated by pressure within the cuff and connector means by which the cuff can be inflated, the balloon and the connector means being formed integrally with one another as a one-piece assembly of thermoplastics material, and the thickness of material in the region of the balloon being less than that in the region of the connector means.

The connector means preferably has a female iuer-tapered bore. The balloon may have a substantially flat face that is deformed outwardly by pressure in the balloon. The balloon may have a wall with a thickness between substantially 0.05 mm and 0.35 mm, and preferably has a wall thickness of between substantially 0.08 mm and 0.15 mm.

The thickness of material in the region of the connector means is preferably between 1.0 mm and 2.00 mm.

The balloon and the connector means are preferably formed integrally as a one-piece moulding which may be an injection blow moulding or dip blow moulding.

The balloon may have a tubular extension extending to the connector means, the wall thickness of the tubular extension being greater than that of the balloon. The wall thickness of the tubular extension is preferably less than that in the region of the connector means.

The assembly may be of PVC.

According to another aspect of the present invention there is provided a medico-surgical tube including a tubular member, a cuff encircling the tubular member, an inflation lumen opening into the cuff by which the cuff can be inflated to seal the tube with a body cavity, and an inflation indicator according to the above one aspect of the present invention.

The tube may be a tracheal tube, inflation of the cuff sealing the tube with a patient's trachea.

Because the balloon and connector are formed as an integral one-piece assembly, this avoids an assembly operation, and ensures that there is no leakage between the connector and the balloon.

A tracheostomy tube assembly including an inflation indicator, both in accordance with 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 assembly; Figure 2 is a cross-sectional side elevation of a part of the tube assembly to a large scale; and Figure 3 is an end view along the arrow Ill of the part shown in Figure 2.

With reference first to Figure 1, the tracheostomy tube assembly comprises a conventional angled tube 1, the patient end 2 of which is located within the trachea 3 via an opening 4 in the patient's throat.

A flexible cuff 5 encircles the tubular member 1 close to its patient end 2. The interior of the cuff 5 communicates with a lumen 6 that extends along the tubular member 2 within its wall. The lumen 6 is sealed at the machine end of the tubular member and is joined to the patient end of a small-bore flexible tube 7 of PVC. The machine end of the smallbore tube 7 is connected to an inflation indicator assembly 20, which is shown in more detail in Figures 2 and 3.

Turning now also to Figures 2 and 3, the inflation indicator assembly 20 is an integral one-piece moulding of plasticised PVC or a similar thermoplastic material which is preferably made by injection blow moulding or by dip blow moulding.

Towards its patient end 21 the assembly has an indicator balloon 22 and, at its machine end 23 the assembly is provided with a luer-tapered female connector 24. The balloon 22, in its uninflated state, has two flat faces 25 and 26 of oval shape that extend to a short tubular nose 27 of circular section at its patient end. The wall thickness of the balloon 22 is preferably between about 0.08 mm and 0.15 mm, but may be between 0.05 mm and 0.35 mm so that the walls are deformed outwardly to a substantially circular cross-section at the normal pressures met within the inflated cuff 5. The machine end of the balloon 22 extends to a tubular extension 28 having a thicker wall which is substantially equal to that of the patient end nose 27, being about 0.675 mm thick, although it may be between 0.6 mm and 1.2 mm.The tubular extension 28 provides a sufficient length between the balloon 22 and the tapered connector 24 to enable the assembly 20 to be clamped closed.

The wall thickness of the assembly 20 is increased further in the region of the connector 24 to about 1.10 mm, although this may be between 1.0 mm and 2.00 mm so that this region is substantially stiffer.

The inflation indicator assembly 20 also includes an integral plug 40 formed as one-piece with the remainder of the assembly. The plug 40 comprises a tapered stopper 41 attached with the body of the assembly 20 by a flexible strap 42, the size of the stopper being such that it can be used to block the opening of the connector 24.

The entire inflation indicator assembly 20 is manufactured as a one-piece integral assembly. The use of standard injection blow moulding dip blow moulding techniques enables the substantial variation in wall thickness to be achieved and the balloon wall to be sufficiently thin to enable the balloon to be inflated and give the necessary sensitivity to pressure. Previous techniques used with non-thermoplastic materials, such as, latex dipping, do not enable variations in thickness to be achieved and would result in a balloon of reduced sensitivity.

The nose 27 can be readily joined to the smallbore inflation tube 7 which is inserted within the nose and sealed by welding or by an adhesive or solvent.

The cuff 5 is inflated by inserting the nose 10 of a syringe 11 into the connector 24 where it forms a luer slip-fit with the tapered bore of the connector.

The plunger 12 of the syringe 11 is then depressed to introduce a measured volume of air to the cuff 5 via the inflation indicator assembly 20, the smallbore tube 7 and the lumen 6. This causes the cuff 5 to inflate and seal with the patient's trachea 3. The consequent increase in pressure within the cuff 5 is communicated to the balloon 22, thereby causing the walls of the balloon to be deflected outwardly until it is almost circular in section. The assembly 20 is then sealed by pinching orfolding the extension 28 while the syringe 11 is removed and the plug 40 is pushed into the connector 24to seal it permanently. By observation of the shape of the balloon 22, any change in pressure within the cuff 5 is readily apparent.

Because the balloon is made as an integral onepiece assembly with the connector, there is no risk of leakage between the balloon and connector. The assembly operation that was previously necessary to join a balloon with a connector is obviated by this assembly, thereby leading to a significant simplification and reduction in cost of the tracheostomy tube.

The balloon of the inflation indicator may have any alternative shape which is such that the shape changes visibly when the cuff is inflated.

Claims

1. An inflation indicator for a cuffed medicosurgical tube, the indicator including a balloon that is inflated by pressure within the cuff and connector means by which the cuff can be inflated, wherein the balloon and the connector means are formed integrally with one another as a one-piece assembly of thermoplastics material, and wherein the thickness of material in the region of the balloon is less than that in the region of the connector means.

2. An inflation indicator according to Claim 1, wherein the connector means has a female luertapered bore.

3. An inflation indicator according to Claim 1 or 2, wherein the balloon has a substantially flat face that is adapted to be deformed outwardly by pressure in the balloon.

4. An inflation indicator according to any one of the preceding claims, wherein the balloon has a wall with a thickness between substantially 0.05 mm and 0.35 mm.

5. An inflation indicator according to Claim 4, wherein the wall thickness of the balloon is between substantially 0.08 mm and 0.15 mm.

6. An inflation indicator according to any one of the preceding claims, wherein the thickness of material in the region of the connector means is between substantially 1.0 mm and 2.0 mm.

7. An inflation indicator according to any one of the preceding claims, wherein the balloon and the connector means are formed integrally as a onepiece moulding.

8. An inflation indicator according to Claim 7, wherein the moulding is an injection blow moulding.

9. An inflation indicator according to Claim 7, wherein the moulding is a dip blow moulding.

10. An inflation indicator according to any one of the preceding claims, wherein the balloon has a tubular extension extending to the connector means, and wherein the wall thickness of the tubular extension is greater than that of the balloon.

11. An inflation indicator according to Claim 10, wherein the wall thickness of the tubular extension is less than that in the region of the connector means.

12. An inflation indicator according to any one of the preceding claims, wherein the assembly is of PVC.

13. An inflation indicator substantially as hereinbefore described with reference to the accompanying drawings.

14. A medico-surgical tube including a tubular member, a cuff encircling the tubular member, an inflation lumen opening into the cuff by which the cuff can be inflated to seal the tube with a body cavity, and an inflation indicator according to any one of the preceding claims.

15. A medico-surgical tube according to Claim 14, wherein the tube is a tracheal tube, and wherein inflation of the cuff seals the tube with a patient's trachea.

16. A tracheal tube substantially as hereinbefore described with reference to the accompanying drawings.

17. Any novel feature or combination of features can hereinbefore described.