NASAL CANNULA MANIFOLD

Abstract

Aspects and embodiments relate to a nasal cannula manifold. The nasal cannula manifold comprises: an inlet configurable to receive pure oxygen or oxygen-enriched therapeutic gas from a gas supply line and at least one outlet insertable into a nasal opening to deliver said oxygen or oxygen-enriched therapeutic gas. At least a portion of the outlet comprises a polymeric material which is fire resistant in the presence of the oxygen or oxygen-enriched therapeutic gas. Aspects and embodiments recognise that it may be possible to provide a comfortable, yet fire resistant, nasal cannula by providing at least an inner portion of the nasal cannula manifold which is fire resistant in an oxygen enriched environment, yet retaining a soft pliable feel to at least an outer, client interface, region of a cannula outlet, such that patient comfort is maintained.

Claims

1. A nasal cannula manifold comprising: an inlet configurable to receive pure oxygen or oxygen-enriched therapeutic gas from a gas supply line; and an outlet insertable into a nasal opening to deliver the oxygen or oxygen-enriched therapeutic gas; and wherein at least a portion of the outlet comprises a polymeric material which is fire resistant in the presence of the oxygen or oxygen-enriched therapeutic gas.

2. The nasal cannula manifold according to claim 1, wherein the portion of the outlet comprising a polymeric material which is fire resistant in the presence of the oxygen or oxygen-enriched therapeutic gas comprises at least a portion of an inner surface of the outlet.

3. The nasal cannula manifold according to or claim 2, wherein the portion of the outlet comprising a polymeric material which is fire resistant in the presence of the oxygen or oxygen-enriched therapeutic gas comprises an entirety of the inner surface of said outlet.

4. The nasal cannula manifold according to claim 2, wherein the portion of the outlet comprising a polymeric material which is fire resistant in the presence of the oxygen or oxygen-enriched therapeutic gas comprises a layer forming the inner surface of the outlet.

5. The nasal cannula manifold according to claim 2, wherein the portion of the outlet comprising a polymeric material which is fire resistant in the presence of the oxygen or oxygen-enriched therapeutic gas comprises an insert forming the inner surface of the outlet.

6. The nasal cannula manifold according to claim 2, wherein the portion of the outlet comprising a polymeric material which is fire resistant in the presence of the oxygen or oxygen-enriched therapeutic gas comprises a coating forming the inner surface of the outlet.

7. The nasal cannula manifold according to claim 4, wherein the layer comprises a portion of an inner surface of the nasal cannula manifold.

8. The nasal cannula manifold according to claim 7, wherein the layer comprises substantially an entirety of an inner surface of the nasal cannula manifold.

9. The nasal cannula manifold according to claim 1, further comprising a body portion and wherein an inner surface of the body portion which extends into the outlet comprises a curved surface.

10. The nasal cannula manifold according to claim 1, wherein the polymeric material which is fire resistant in the presence of the oxygen or oxygen-enriched therapeutic gas comprises: fluorinated ethylene propylene (FEP), polychlorotrifluoroethylene (PCTFE), perfluoroalkoxy polymer (PFA) or polytetrafluoroethylene (PTFE).

11. The nasal cannula manifold according to claim 1, wherein an outer portion of the outlet comprises a pliable deformable polymeric material.

12. The nasal cannula manifold according to claim 11, wherein the pliable deformable polymeric material comprises: plasticised polyvinyl chloride (PVC) or silicone rubber.

13. The nasal cannula manifold according to claim 1, further comprising a body portion formed from plasticised polyvinyl chloride (PVC) or silicone rubber.

14. The nasal cannula manifold according to claim 1, further comprising a body portion formed from a silicone substrate and coated, at least internally, with fluorinated ethylene propylene (FEP).

15. The nasal cannula according to claim 14, wherein the (FEP) coating is applied by baking a fluorinated ethylene propylene (FEP) dispersion coating at a temperature below a melting temperature of the silicone substrate.

16. (canceled)

17. (canceled)

18. (canceled)

19. (canceled)

20. (canceled)

21. (canceled)

22. A nasal cannula manifold, comprising: an inlet configurable to receive pure oxygen-enriched therapeutic gas from a gas supply line; and a pair of outlets insertable into a nasal opening to delivery the oxygen or oxygen-enriched therapeutic gas, wherein the outlets comprise: an insert forming an inner surface of the pair of outlets; a pair of conduits within the insert that are in gas communication with the inlet, each conduit of the pair of conduits being receivable within a corresponding outlet of the pair of outlets; and a coupling portion coupling the pair of conduits together.

23. The nasal cannula manifold according to claim 22, wherein a first conduit of the pair of conduits is coupled with a first end of the coupling portion, a second conduit of the pair of conduits is coupled with a second end of the coupling portion and the coupling portion is curved to locate the first conduit of with respect to the second conduit.

24. The nasal cannula manifold according to claim 23, wherein the coupling portion is locatable to urge at least a portion of opposing walls of the nasal cannula manifold apart.

25. (canceled)

26. The nasal cannula manifold according to claim 24, wherein the pair of conduits are dimensioned to extend beyond the inner surface of the pair of outlets.

27. (canceled)

28. A medical gas delivery apparatus comprising: a nasal cannula manifold, the nasal cannula manifold comprising: an inlet configurable to receive pure oxygen or oxygen-enriched therapeutic gas from a gas supply line; and an outlet insertable into a nasal opening to deliver the oxygen or oxygen-enriched therapeutic gas; and wherein at least a portion of the outlet comprises a polymeric material which is fire resistant in the presence of the oxygen or oxygen-enriched therapeutic gas.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Embodiments of the present invention will now be described further, with reference to the accompanying drawings, in which:

[0045] FIG. 1a illustrates schematically a nasal cannula manifold and therapeutic gas supply line according to an arrangement;

[0046] FIG. 1b illustrates schematically a fire resistant portion of a nasal cannula manifold and therapeutic gas supply line according to the arrangement of FIG. 1a;

[0047] FIG. 2a illustrates schematically a nasal cannula manifold and therapeutic gas supply line according to a further arrangement;

[0048] FIG. 2b illustrates schematically a fire resistant portion of a nasal cannula manifold and therapeutic gas supply line according to the arrangement of FIG. 2a;

[0049] FIG. 3a illustrates schematically a nasal cannula manifold and therapeutic gas supply line according to a further arrangement;

[0050] FIG. 3b illustrates schematically a fire resistant portion of a nasal cannula manifold and therapeutic gas supply line according to the arrangement of FIG. 3a;

[0051] FIG. 4a illustrates schematically a nasal cannula manifold and therapeutic gas supply line according to a further arrangement;

[0052] FIG. 4b illustrates schematically a fire resistant portion of a nasal cannula manifold and therapeutic gas supply line according to the arrangement of FIG. 4a;

[0053] FIG. 5a illustrates schematically a nasal cannula manifold and therapeutic gas supply line according to a further arrangement; and

[0054] FIG. 5b illustrates schematically a fire resistant portion of a nasal cannula manifold and therapeutic gas supply line according to the arrangement of FIG. 5a.

DESCRIPTION OF THE EMBODIMENTS

[0055] Before describing arrangements in detail, a general overview is provided: as described above, therapeutic medical gas is often supplied to a patient via flexible polymeric tubing which connects a gas supply via appropriate flow regulation apparatus, such as a flow meter, to an administration device. The administration device may comprise a nasal cannula or mask, via which oxygen is delivered to a patient.

[0056] A nasal cannula typically comprises a nasal cannula manifold which is inserted in-line to a gas supply line. Accordingly, a nasal cannula manifold may comprise a main body portion. The main body portion of a nasal cannula manifold typically includes at least one inlet configured to receive a gas supply line. The therapeutic gas enters the manifold via the inlet. The main body portion of a nasal cannula manifold typically further comprises at least one outlet, via which therapeutic gas may be delivered to a patient. At least one outlet may comprise a nasal prong for insertion into a nasal cavity of a patient. The outlet portion of the manifold thus forms a primary patient interface and the interaction and interface between the outlet portion and a patient forms the basis for patient comfort in relation to use of a nasal cannula.

[0057] Exposure of oxygen delivery apparatus to an ignition event, for example, an open flame or cigarette, can result in ignition. An external fire may be supported by the oxygen supplied by the delivery apparatus. In extreme circumstances, the oxygen can support an external fire that may move to the interior of the flexible tubing and may migrate rapidly upstream towards the oxygen source. Typically fuel is required to support a fire. In the case of an ignition event near to patient delivery, it may be the cannula or mask which supplies such fuel. Where a nasal cannula is ignited in the fire during active therapy, the prongs of the nasal cannula, which may be delivering a flow of high purity oxygen, can rapidly combust thereby ejecting a burst of flame, hot toxic gases and smoke directly into the patient's nasopharynx and airways, causing potentially life threatening injury. This can be particularly serious for patients receiving home oxygen therapy who are commonly prescribed oxygen therapy for chronic respiratory disease.

[0058] Arrangements recognise that it may be possible to include at least a region of polymeric material which is fire resistant in an oxygen enriched environment within a nasal cannula manifold. Appropriate placing, together with appropriate methods of manufacture may allow for provision of a nasal cannula which offers some improvement, including fire resistance, when compared to a typical plasticised PVC nasal cannula.

[0059] Arrangements recognise that provision of a region of polymeric material which is fire resistant in an oxygen enriched environment, may require provision of a region of polymeric material with a limiting oxygen index of greater than 95%. Such polymeric materials may comprise perfluoropolymers, for example, fluorinated ethylene propylene (FEP), polychlorotrifluoroethylene (PCTFE), perfluoroalkoxy polymer (PFA) or polytetrafluoroethylene (PTFE). Inclusion of such polymeric materials within a nasal cannula manifold is challenging, as a result of the high temperatures associated with many manufacturing techniques, when taken in combination with the relatively low melting point of softer polymers materials which it may be desired to include within a nasal cannula manifold for reasons of patient comfort.

[0060] Inclusion of an appropriate region of fire resistant polymeric material with a limiting oxygen index of greater than 95% may have other advantages, as a result of some of the other properties of such polymeric materials. Polymeric materials comprising, for example, fluorinated ethylene propylene (FEP), polychlorotrifluoroethylene (PCTFE), perfluoroalkoxy polymer (PFA) or polytetrafluoroethylene (PTFE) may have a high level of hydrophobicity compared to the hydrophobicity of plasticised PVC or silicone used in a typical nasal cannula and thus offer improved resistance to soiling and/or clogging with dirt, when in use. Furthermore, depending upon the particular arrangement of the fire resistant polymeric material, it may be possible to reduce or mitigate hardening of the nasal cannula manifold. Increased, resistance to soiling, together with an increased period for which a nasal cannula manifold patient interface might remain pliable and soft may allow for an overall increase in nasal cannula manifold lifetime.

[0061] Some arrangements are described in more detail in relation to the attached figures. Where possible, reference numerals have been reused as appropriate throughout the figures to label analogous parts. In each set of figures, a cross-sectional cutaway schematic of a nasal cannula manifold installed in-line in a gas supply is provided, together with a separate cross-sectional schematic showing just a region of fire resistant polymeric material included within the cross-sectional cutaway schematic of a nasal cannula manifold installed in-line.

[0062] FIG. 1a illustrates schematically a nasal cannula manifold and therapeutic gas supply line according to an arrangement and FIG. 1b illustrates schematically a fire resistant portion of a nasal cannula manifold and therapeutic gas supply line according to the arrangement of FIG. 1a. In this arrangement, the nasal cannula manifold is formed from at least two separate pieces and assembled to form a composite manifold assembly.

[0063] A nasal cannula 100 typically comprises a nasal cannula manifold 10 which is inserted in-line to a gas supply line 20a, 20b. Accordingly, a nasal cannula manifold 10 may comprise a main body portion 30. The main body portion 30 of the nasal cannula manifold 10 typically includes at least one inlet 40a, 40b configured to receive the gas supply line 20a, 20b. The therapeutic gas enters the main body 30 of the manifold 10 via the inlet 40a, 40b. The main body portion 30 of the nasal cannula manifold 10 typically further comprises at least one outlet 50a, 50b, via which therapeutic gas may be delivered to a patient (not shown). The at least one outlet 50a, 50b may comprise a nasal prong 60a, 60b for insertion into a nasal cavity of a patient. The outlet portion 50a, 50b, 60a, 60b, of the manifold 10 thus forms a primary patient interface and the interaction and interface between the outlet portion and a patient forms the basis for patient comfort in relation to use of a nasal cannula 10.

[0064] In the arrangement of FIG. 1, the manifold 10 includes a portion of said outlet which comprises a polymeric material which is fire resistant in the presence of said oxygen or oxygen-enriched therapeutic gas. The fire resistant material in the arrangement of FIG. 1 comprises a pair of perfluoropolymer inserts 70a, 70b which can be inserted, for example, into the nasal prongs 60a, 60b of a pre-formed manifold 10 made, for example, of plasticised PVC. The inserts 70a, 70b may include one or more lateral protrusions 80 which engage with the inner surface of the PVC nasal prong 60a, 60b and thus provide a close friction fit of the inserts in place within the manifold. It can be seen that in the arrangement of FIGS. 1a and 1b, the inserts are dimensioned to cover substantially the entire of the inner surface of the PVC nasal prongs 60a, 60b. The outside of the nasal prongs 60a, 60b are, in this example, formed from plasticised PVC. The outside of the nasal prongs is the portion of the manifold which may be in contact with a patient and thus it is desirable for the outer surface of the prongs to be relatively soft and pliable for patient comfort.

[0065] In use, the presence of the fire resistant inserts may act to arrest a fire, or resist ignition of the nasal prongs and mitigate a fire before it reaches the main body 30 of the manifold 10 and may help to limit the chance of a fire reaching the supply line 20a, 20b and tracking back to the gas source. It will be understood that in the arrangement shown in FIG. 1, the nasal cannula manifold is formed from at least two separate pieces and assembled to form a manifold assembly.

[0066] FIG. 2a illustrates schematically a nasal cannula manifold and therapeutic gas supply line according to a further arrangement. FIG. 2b illustrates schematically a fire resistant portion of a nasal cannula manifold and therapeutic gas supply line according to the arrangement of FIG. 2a. The general method of construction in relation to the arrangement of FIG. 2 is that of providing a manifold core 90 from a fire resistant polymeric material and overmoulding the outer surface of that core 90 with a softer polymeric material. The softer polymeric material layer 110 is provided for the purposes of providing an outer surface to the nasal prongs 60a, 60b which is comfortable to a patient, whilst ensuring that at least a portion (in the example of FIG. 2, the entire inner surface) of the inner surface of the manifold 10 which is in contact with oxygen enriched gas is substantially fire resistant.

[0067] In use, the presence of the fire resistant core may act to arrest a fire, or resist ignition of the nasal prongs and main body of the manifold 10 and may help to limit the chance of a fire reaching the supply line 20a, 20b and tracking back to the gas source. It will be understood that in the arrangement shown in FIG. 2, the nasal cannula manifold is a unitary manifold: the core and coating layer may be substantially inseparable.

[0068] Forming an inner surface from a suitably selected fire resistant polymeric material may have further benefits: maintaining a smooth inner surface may minimise any disruption to gas flow; may minimise chances of detritus being caught in the manifold and disrupting gas flow; and/or may mitigate overall soiling of the inside of the manifold, if the fire resistant polymeric material is sufficiently hydrophobic.

[0069] FIG. 3a illustrates schematically a nasal cannula manifold and therapeutic gas supply line according to a further arrangement and FIG. 3b illustrates schematically a fire resistant portion of a nasal cannula manifold and therapeutic gas supply line according to the arrangement of FIG. 3a. The general method of construction in relation to the arrangement of FIG. 3 is that of coating a moulded polymeric manifold core 120 with a layer of fire resistant polymeric material 130. The layer of fire resistant polymeric material 130 may comprise a perfluoropolymer coating.

[0070] Again in use, the presence of the fire resistant core may act to arrest a fire, or resist ignition of the nasal prongs and main body of the manifold 10 and may help to limit the chance of a fire reaching the supply line 20a, 20b and tracking back to the gas source. It will be understood that in the arrangement shown in FIG. 3, the nasal cannula manifold is a unitary manifold: the core and coating layer may be substantially inseparable.

[0071] Forming an inner surface from a suitably selected fire resistant polymeric material may have further benefits: maintaining a smooth inner surface may minimise any disruption to gas flow; may minimise chances of detritus being caught in the manifold and disrupting gas flow; and/or may mitigate overall soiling of the inside of the manifold, if the fire resistant polymeric material is sufficiently hydrophobic.

[0072] FIG. 4a illustrates schematically a nasal cannula manifold and therapeutic gas supply line according to a further arrangement and FIG. 4b illustrates schematically a fire resistant portion of a nasal cannula manifold and therapeutic gas supply line according to the arrangement of FIG. 4a. The general method of construction in relation to the arrangement of FIG. 4 is that of providing a fire resistant polymeric nasal bridge 140 and dip coating or overmoulding that bridge to form a complete polymeric manifold. The nasal bridge 140 may comprise a perfluoropolymer nasal bridge.

[0073] Again in use, the presence of the fire resistant nasal bridge, forming the inner surface of the nasal prongs 60a, 60b and a portion of the inner surface of the main body 30 of the manifold 10 may act to arrest a fire, or resist ignition of the nasal prongs and main body of the manifold 10 and may thus help to limit the chance of a fire reaching the supply line 20a, 20b and tracking back to the gas source. It will be understood that in the arrangement shown in FIG. 4, the nasal cannula manifold is a unitary polymeric manifold: the core and coating layer may be substantially inseparable.

[0074] The arrangement of FIG. 4 is may be advantageous because the inner fire resistant polymer piece may be injection moulded without the need to withdraw a core pin required to mould the fire resistant piece, such as the one shown schematically in FIG. 2. This enables a substantial radius 150 to the formed at the inside of the base of the nasal prong 60a, 60b. As such, turbulence in the gas stream is minimised and a sharp transition of the inner surface which may cause edges where mucus or other foreign bodies may be prone to collect or attach may be avoided.

[0075] FIG. 5a illustrates schematically a nasal cannula manifold and therapeutic gas supply line according to a further arrangement and FIG. 5b illustrates schematically a fire resistant portion of a nasal cannula manifold and therapeutic gas supply line according to the arrangement of FIG. 5a. The general method of construction in relation to the arrangement of FIG. 5 is that of providing a moulded, fire resistant polymeric insert 160 which is inserted into the manifold 10.

[0076] The insert has a pair of tubular conduits 170, 180. The pair of conduits 170, 180 are joined by a U-shaped connector 190. Hence, the pair of conduits 170, 180 are held in a fixed arrangement with respect to each other. Each conduit 170, 180 has a pair of openings 173, 175, 183, 185. The U-shaped connector 190 is a sectioned tube which enables the openings 173, 183 to receive the oxygen or oxygen-enriched therapeutic gas flowing within the manifold 10. The oxygen or oxygen-enriched therapeutic gas is then delivered to the openings 183, 185 which are received by nasal cavities.

[0077] Accordingly, the manifold 100 includes a portion of said outlet which comprises a polymeric material which is fire resistant in the presence of said oxygen or oxygen-enriched therapeutic gas. The fire resistant material in the arrangement of FIG. 5 comprises a single perfluoropolymer insert 160 which can be inserted through the nasal prongs 60a, 60b of a pre-formed manifold 10 made, for example, of plasticised PVC. The ends of the insert 160 provide a diameter larger than the internal diameter of the manifold 10 to provide a secure fit of the insert 160 once in place within the manifold 10. It can be seen that in the arrangement of FIGS. 5a and 5b, the inserts are dimensioned to cover substantially the inner surface of the nasal prongs 60a, 60b. The U-shaped connector 190 is dimensioned to provide a sliding fit within the manifold 10 and to hold walls of the manifold 10 in the vicinity of the U-shaped connector 190 apart. The openings 175, 185 define an annular ring 200 of fire resistant material. This provides fire resistant material at the end face of the openings 175, 185 and also on the external face of the openings 175, 185. The annular ring 200 is typically dimensioned to extend along the external face of the openings only by that distance for which the concentration of oxygen is sufficient to support combustion.

[0078] The arrangement of FIG. 5 is may be advantageous because the inner fire resistant polymer piece may be injection moulded without the need to withdraw a core pin required to mould the fire resistant piece, such as the one shown schematically in FIG. 2. This enables the substantial U-shaped connector 190 to be the formed at the inside of the base of the nasal prong 60a, 60b. As such, turbulence in the gas stream is minimised and a sharp transition of the inner surface which may cause edges where mucus or other foreign bodies may be prone to collect or attach may be avoided. Also, this arrangement is significantly easier to fit than the arrangement shown in FIG. 4.

[0079] Embodiments may include an appropriate region of fire resistant polymeric material such as perfluoroelastomer (FFPM).

[0080] Although illustrative embodiments of the invention have been disclosed in detail herein, with reference to the accompanying drawings, it is understood that the invention is not limited to the precise embodiment and that various changes and modifications can be effected therein by one skilled in the art without departing from the scope of the invention as defined by the appended claims and their equivalents.