GB2137096A - Oropharyngeal airway - Google Patents

Abstract

There is disclosed an oropharyngeal airway (10) which comprises a curved portion (11) which provides a pharyngeal end (12) of the airway, and a straight portion (13) which communicates with the curved portion (11) and which provides a buccal end (14) of the airway. The straight portion (13) is formed integrally with the curved portion (11) and is made from plastics and/or elastomeric material. At least one circular cross- section passage extends substantially throughout the length of the straight portion (13), and the straight portion (13) has a substantial wall thickness surrounding the passage to provide rigidity sufficient to resist collapse of the straight portion under biting-action of a patient. Conveniently, one of the passages serves as a catheter guide, while the remaining passage serves to convey air to the curved portion. <IMAGE>

Description

SPECIFICATION Oropharyngeal airway This invention relates to an oropharyngeal airway, which is a device intended to maintain the patency of the respiratory passages through the oral cavity and pharynx.

An oropharyngeal airway comprises a tube having one end (the pharyngeal end) which is intended to be inserted into a patient's oropharynx and an opposite end (the buccal or flanged end) which is flanged and is intended to fit between the teeth or gums at the lips of the patient.

It is known to make the airways of plastics material, such as EVA (ethlene/vinyl acetate copolymer) or PVC and various elastomeric materials. The material should have the dual properties of (a) sufficient smoothness and softness to suit a patient and (b) sufficient rigidity to prevent collapse of the walls of the airway.

When the airway is made of plastics material, it is usual to provide a rigid insert at the buccal end, to prevent collapse of the buccal end when bitten by the patient.

One known type of airway, referred to as the Guedel airway, has a tube of substantially rectangular cross-section (with rounded ends) which extends from the pharyngeal end in a curved portion which subtends an angle of about 900, and then merges into a short straight portion which extends away from the curved portion at an angle of about 300 towards the buccal end. At the buccal end, there is a generally elliptical flange formed integrally with the short straight portion of the tube and extending in a plane perpendicular to the inlet to the tube at the buccal end. To prevent collapse of the walls of the tube in the short straight portion at the buccal end, a separately formed insert of rigid plastics material is pressfitted into the inlet end of the airway.The short straight portion has the same substantially rectangular cross section as that of the curved portion, and the external cross section of the insert is of a similar, but slightly smaller shape to permit of insertion into the inlet end. The insert necessarily has an appreciable wall thickness to provide it with the necessary rigidity, and therefore the internal cross-section of the insert is appreciably smaller in area than that of both the straight and the curved portions of the airway.

This has four disadvantages.

First of all, the insert reduces the airflow rate which can be achieved, as compared with an airway Jacking the insert. Secondly, when it is necessary to use a catheter to remove mucous from a patient who is using the airway (the catheter is manoeuvred into the required position by entry through the buccal end of the airway and along the airway), the small cross-section of the insert imposes a restriction of the maximum diameter of catheter which can be used.

Thirdly, when a catheter is taken through the airway from the buccal end to the pharyngeal end, there is a risk that, on occasions the catheter (which is relatively flexible and normally of an external diameter only slightly less than the narrow dimension of the rectangular cross-section of the insert) may adopt a somewhat sinuous path as it is pushed down the airway. This may result in the catheter extending from one of the narrow sides of the rectangular internal cross-section of the insert cind/or the airway to an opposite one of the narrow sides whereby the catheter substantially blocks, or at least impedes the flow of air along the airway with inevitable temporary distress to the patient while the catheter is being used.Fourthly, by providing a press-fitted and separately formed insert, there is a risk that the insert may become dislodged from its proper position in service, with evident risk to the patient.

Accordingly, there has developed a need to improve the known Guedel type of orophryngeal airway in one or more of the four respects referred to above i.e. (a) provide bite resistance at the buccal end without reducing the air flow performance of the remainder of the airway, (b) enable larger diameter catheters to be used than is possible with existing Guedel type airways with inserts, (c) provide guidance for the insertion of the catheter so as to minimise the risk of the catheter adopting a path in which it obstructs the flow of air through the airway, and (d) avoids the necessity to provide a separately formed and insertable (and therefore also removeable) component at the buccal end.

According to one aspect of the invention there is provided an oropharyngeal airway comprising a curved portion which provides a pharyngeal end of the airway, and a straight portion which communicates with the curved portion and which provides a buccal end of the airway; in which the straight portion is formed integrally with the curved portion and is made from plastics and/or elastomeric material with at least one circular cross-section passage extending substantially throughout the length of the straight portion, said straight portion having a substantial wall thickness surrounding the passage to provide rigidity to the straight portion for resisting collapse of the straight portion under biting-action of a patient.

In addition to providing the necessary resistance to collapse under biting action (hitherto provided by a separate insert with the disadvantages referred to above), the passage (referred to hereinafter as the first passage) also may act as a catheter guide which directs the catheter in such a way that it will tend to run in a substantially straight line from the straight portion and through the curved portion of the airway, so that the risk of obstruction of the curved portion by the catheter is substantially minimised.

However, when the first passage is intended to act as a catheter guide, the straight portion of the airway will be formed with a second passage, preferably of similar shape, through which air can flow to the patient when the first passage is used to guide the catheter.

In order that the provision of bite resistant at the buccal end of the airway should not impair the air flow rate through the curved portion, it is preferred that the cross-sectional area of the first mentioned passage, or that of the combined cross-sectional areas of the first and second passages when two passages are provided, should be greater than the internal cross-sectional area of the curved portion.

If it is desired to provide an airway with which can be used catheters of different sizes, and bigger than possible with existing Guedel type airways, suitably sized passages may be formed in the straight portion of the airway in simple manner, without substantially reducing the bite resistance at the buccal end.

According to a further aspect of the invention there is provided an oropharyngeal airway comprising a curved portion which provides a pharyngeal end of the airway, and a straight portion which communicates with the curved portion and which provides a buccal end of the airway; in which the straight portion is formed of plastics and/or elastomeric material and has at least one through-passage formed therein with a surrounding wall thickness sufficient to prevent collapse under biting-action of a patient.

Preferably, two passages are provided, either one of which can be used to guide the insertion of a catheter, and the remaining one then serving to convey air to the curved portion of the airway.

Conveniently, the or each passage is circular in cross-section, and preferably the cross-sectional area of the passage(s) is greater than the internal cross-sectional area of the curved portion, so that the buccal end does not limit the air flow rate through the curved portion despite bite-resistance and catheter-guidance properties provided at the buccal end of the straight portion of the airway.

Preferably, the oropharyngeal airway is made of plastics and/or elastomeric material which has the required smoothness and softness to suit the intended use, but has sufficient rigidity to resist collapse under biting action at the buccal end. One preferred plastics material from which the airway may be made is EVA.

One embodiment of oropharyngeal airway according to the invention will now be described in detail, by way of example only, with reference to the accompanying drawings in which:~ Figure 1 is a plan view of the oropharyngeal airway; Figure 2 is a side view of the airway; Figure 3 is an underplan view of the airway; Figure 4 is a front view at the buccal end of the airway; Figure 5 is a rear view at the pharyngeal end of the airway; Figure 6 is a section taken on the line A-A in Figure 4; Figure 7 is a section taken on the line B-B in Figure 4; Figure 8 is a section on the line C-C in Figure 1 ; and Figure 9 is a section taken on the line D-D in Figure 1.

Referring now to the drawings, there is shown one embodiment of oropharyngeal airway according to the invention which is designated generally by reference numeral 10. The airway 10 comprises a tubular curved portion 1 1 which provides, at its end 12, a pharyngeal end of the airway, and a straight portion 13 which communicates with the curved portion 11 and which provides, at its end 14, a buccal end of the airway. In use with a patient, the airway 10, as illustrated in the drawings, will be rotated through 1800 prior to entry of the curved portion 1 1 through the mouth of the patient.

The curved portion 1 1 of the airway 10 is of generally rectangular internal cross-section, with rounded ends at the narrow sides of the cross section. The curved portion 1 1 subtends an angle at its centre of curvature of about 900, and the straight portion 13 merges with, but extends away from the cuved portion 11 at an angle of about 300.

At the inlet end of the airway, the straight portion 13 is provided with an elliptical flange 15 which surrounds the inlet and extends in a plane perpendicular to the longitudinal axis of the straight portion 13. Communication is provided between the curved portion 11 with its rectangular internal cross-section and the straight portion 13 by means of first and second throughpassages 16 and 17 formed in the straight portion 13. The passages 16 and 17 are each of circular cross-section, and extend substantially throughout the length of the straight portion 13. As will be seen from the drawings, each of the passages 1 6 and 17 is surrounded by a substantial wall thickness of material which provides rigidity to the straight portion 13 sufficient to resist collapse of the straight portion under biting-action of a patient.

In addition to providing the necessary resistance to collapse under biting-action (hitherto provided by a separate insert in conventional constructions of Guide type airways), the first and second passages 16 and 17 may each serve as a catheter guide to direct the catheter through the airway in such a way that the catheter will tend to run in a substantially straight line from the straight portion 13 and through the curved portion 11 so that the risk of obstruction of the curved portion 1 1 by the catheter is substantially minimised.

When one of the passages is used as a catheter guide, the other passage can still function to permit air to flow to the patient. The sizes of the passages 16 and 17 may be selected to suit any diameter of a particular catheter intended to be used with the airway.

In order that the provision of bite resistance at the buccal end of the airway should not impair the air flow rate through the curved portion 1 1 (having rectangular internal cross-section), it is preferred that the combined cross-sectional areas of the first and second passages 16 and 17 should be at least as great as, or more than the internal crosssectional area of the curved portion 1 1. While it is preferred that first and second passages 1 6 and 17 be provided in the straight portion 13, it is within the scope of the invention for a single passage to be provided, or more than two passages if desired.

The oropharyngeal airway 10 described and illustrated herein is formed of plastics and/or elastomeric material which has the required smoothness and softness to suit the intended use, but which has sufficient rigidity to resist collapse under biting action at the buccal end, and also to maintain free flow of air through the curved portion 11 to the pharyngeal end. One particularly suitable plastics material is EVA.

The airways may be supplied in a range of sizes, preferably seven sizes, to suit children and adults.

Some or all of the features of the invention disclosed herein may be applied to airways for veterinary use.

Claims (10)

1. An oropharyngeal airway comprising a curved portion which provides a pharyngeal end of the airway, and a straight portion which communicates with the curved portion and which provides a buccal end of the airway; in which the straight portion is formed of plastics and/or elastomeric material and has at least one through-passage formed therein with a surrounding wall thickness sufficiednt to prevent collapse under biting-action of a patient.

2. An airway according to claim 1, in which two passages are provided in the straight portion, at least one of which can be used to guide the insertion of a catheter while the other serves to convey air to the curved portion of the airway.

3. An airway according to claim 1 or 2, in which the cross-sectional area of the passage, or the combined cross-sectional areas of the passages, is greater than the internal cross-section of the curved portion.

4. An airway according to any one of the preceding claims, in which the or each passage is circular in cross section.

5. An airway according to any one of the preceding claims, in which the airway is made of plastics and/or elastomeric material.

6. An airway according to claim 5, in which the airway is made of E.V.A.

7. An oropharyngeal airway comprising a curved portion which provides a pharyngeal end of the airway, and a straight portion which communicates with the curved portion and which provides a buccal end of the airway; in which the straight portion is formed integrally with the curved portion and is made from plastics and/or elastomeric material with at least one circular cross-section passage extending substantially throughout the length of the straight portion, said straight portion having a substantial wall thickness surrounding the passage to provide rigidity to the straight portion for resisting collapse of the straight portion under biting-action of a patient.

8. An airway according to claim 7, including a first passage formed in the straight portion to guide the insertion of a catheter and a second passage formed in the straight portion to convey air to the curved portion.

9. An airway according to claim 7 or 8, in which the cross-sectional area of the passage, or the combined cross-sectional area of the passages, is greater than the internal cross-sectional area of the curved portion.

10. An airway according to claim 1 and substantially as hereinbefore described with reference to, and as shown in the accompanying drawings.