Patent Publication Number: US-2023147017-A1

Title: Apparatus for use in a respiratory support system

Description:
TECHNICAL FIELD 
     The present disclosure generally relates to methods and/or structures for preventing contamination of breathing circuits by patients, including but not limited to respiratory support kits or kits comprising respiratory support components to be used in providing respiratory support for patients receiving anaesthesia or undergoing intubation or endoscopy. 
     BACKGROUND 
     Patients may lose respiratory function during anaesthesia, or sedation, or more generally during certain medical procedures. Prior to a medical procedure a patient may be pre-oxygenated by a medical professional to provide a reservoir of oxygen saturation, and this pre-oxygenation is generally carried out with a bag and a face mask. Once under general anaesthesia, patients must be intubated to ventilate the patient. In some cases, intubation is completed in 30 to 60 seconds, but in other cases, particularly if the patient&#39;s airway is difficult to traverse (for example, due to cancer, severe injury, obesity or spasm of the neck muscles), intubation will take significantly longer. While pre-oxygenation provides a buffer against declines in oxygen saturation, for long intubation procedures, it is necessary to interrupt the intubation process and reapply the face mask to increase the patient&#39;s oxygen saturation to adequate levels. The interruption of the intubation process may happen several times for difficult intubation processes, which is time consuming and puts the patient at severe health risk. After approximately three attempts at intubation the medical procedure will be abandoned. 
     Respiratory therapy circuits are typically single use items. Once a therapy circuit, for example a respiratory gas conduit, has been used by a patient, the conduit together with a patient interface is thrown away. One of the reasons for this is to prevent contamination from one patient to another when the same flow source and/or humidifier are used. 
     Respiratory support systems that are used in multiple-patient environments typically require at least an inspiratory conduit and patient interface to be discarded and replaced between each patient to ensure the components provided for use by each patient are clean and not infected from prior users This is time consuming which may be detrimental in an emergency situation. It also creates significant amounts of waste and adds to the overall cost of the procedures or at least to the overall hospital operation costs since the hospital needs to keep a larger stock of inspiratory conduits. This cost can sometimes be passed on to the patient. 
     Humidity allows delivery of gas at high flow rates comfortably to patients so the gas flows can be used during the conscious patient preparation stage. 
     Reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general knowledge in the field of endeavour in any country in the world. 
     SUMMARY 
     It is an object of certain embodiments disclosed herein to provide a method or apparatus that might solve one or more of the above problems, or to at least provide the public with a useful choice. 
     It is an object of certain embodiments disclosed herein to provide an apparatus for use in a respiratory support system that will at least go some way towards improving on the above or which will at least provide the public or the medical profession with a useful choice. It is an alternative or additional object of certain embodiments disclosed herein to provide a kit for use in a respiratory support system that enables an inspiratory conduit to be re-used. 
     Humidified gases can be used to allow for the comfortable gases delivery during the sedated stages of a patient in some configurations. Humidity prevents or helps to minimise the airways from drying out and hence can prevent or minimise damage to the airways and may also improve or assist with maintaining patient comfort when receiving a flow of gases being delivery to their airway(s). 
     Thus, in accordance with at least one of the embodiments disclosed herein, an apparatus or kit for use in a respiratory support system for delivering humidified gas to a user or patient is disclosed. The apparatus or kit comprises:
         a humidifier chamber that is in pneumatic communication with a gases source, or that is configured to be placed in pneumatic communication with the gases source;   an inspiratory conduit that is in pneumatic communication with the humidifier chamber downstream of the humidifier chamber, or that is configured to be placed in pneumatic communication with the humidifier chamber downstream of the humidifier chamber;   a filter that is in pneumatic communication with the inspiratory conduit downstream of the inspiratory conduit, or that is configured to be placed in pneumatic communication with the inspiratory conduit downstream of the inspiratory conduit; and   a patient interface for delivering humidified gas to a user or patient, wherein the patient interface is in pneumatic communication with the filter downstream of the filter, or is configured to be placed in pneumatic communication with the filter downstream of the filter.       

     In the apparatus or kit, the filter may be coupled to the patient interface, or may be configured to be coupled to the patient interface. In the apparatus or kit, the patient interface may comprise a patient interface gases conduit, wherein the filter may comprise a gases inlet port and a gases outlet port, and wherein the gases outlet port of the filter and the patient interface gases conduit may comprise complementary coupling features to enable the filter to be coupled to the patient interface to provide pneumatic communication between the filter and the patient interface gases conduit, with the filter in-line with a gases flow path through the patient interface gases conduit. In the apparatus or kit, the complementary coupling features may be disconnectable from each other to enable the filter to be decoupled from the patient interface gases conduit. 
     The filter may be coupled to an interface tube, such as a patient interface gases conduit, that is coupled to the manifold. The patient interface gases conduit may be a short section of tube or conduit. For example, the patient interface gases conduit may be about 20 cm to about 50 cm long, or about 25 cm to about 40 cm long, or about 30 cm to about 35 cm long, or may be about 32 cm long. 
     In the apparatus or kit, the patient interface may comprise a patient interface gases conduit, wherein the filter may be integrated into the patient interface gases conduit to provide pneumatic communication between the filter and the patient interface gases conduit, with the filter in-line with a gases flow path through the patient interface gases conduit. Optionally, in such an arrangement, a gases inlet to such an integrated filter may comprise of complementary coupling features. Such complementary coupling features may for example be provided by an adapter insert attached to the gases inlet of such an integrated filter component. 
     With reference to the complementary coupling features as described herein, these features may optionally be provided by provision of an adapter insert to the item or component (for example, but not limited to, the gases inlet or gases outlet of: a filter, a conduit, gases inlet to a patient interface) requiring such complementary coupling features to enable a coupling and decoupling or connection and disconnection. Such an adapter insert is described elsewhere in this specification. 
     In the apparatus or kit, a gases inlet port of the filter and a gases outlet port of the inspiratory conduit may comprise complementary coupling features, to enable the inspiratory conduit to be coupled to the filter to provide pneumatic communication between the inspiratory conduit and the filter. In the apparatus or kit, the complementary coupling features of the gases inlet port of the filter and the gases outlet port of the inspiratory conduit may be disconnectable from each other to enable the inspiratory conduit to be decoupled from the filter. 
     In the apparatus or kit, a gases inlet port of the inspiratory conduit and a gases outlet port of the humidifier chamber may comprise complementary coupling features, to enable the inspiratory conduit to be coupled to the humidifier to provide pneumatic communication between the humidifier chamber and the inspiratory conduit. In the apparatus or kit, the complementary coupling features of the gases outlet of the humidifier chamber and the gases inlet of the inspiratory conduit may be disconnectable from each other to enable the inspiratory conduit to be decoupled from the humidifier chamber. 
     The apparatus or kit may further comprise a gases delivery conduit that is in pneumatic communication with the source of gas, or that is configured to be placed in pneumatic communication with the source of gas, wherein the humidifier chamber is in pneumatic communication with the gases delivery conduit downstream of the gases delivery conduit, or is configured to be placed in pneumatic communication with the gases delivery conduit downstream of the gases delivery conduit. In the apparatus or kit, a gases outlet port of the gases delivery conduit and a gases inlet port of the humidifier chamber may comprise complementary coupling features, the complementary coupling features being to enable the gases delivery conduit to be coupled to the humidifier to provide pneumatic communication between the humidifier chamber and the gases delivery conduit. In the apparatus or kit, the gases outlet port of the gases delivery conduit and the gases inlet port of the humidifier chamber comprise complementary coupling features, the complementary coupling features may be disconnectable from each other to enable the gases delivery conduit to be decoupled from the humidifier chamber. 
     In the apparatus or kit, the filter may be a high-efficiency particulate arrestance (HEPA) filter, a pleated sheet filter (such as of the type manufactured of glass micro fibres), nano fibre filter, sock filter, stacked disc filter, spiral filter, block of filter material, a disc of filter material with streams of filter material to free flow from or off the disc in fluid flow, ceramic type filter, fabricated material type filter (such as a woven wire cloth), porous plastic type filter (such as plastic powders moulded into porous rigid shape type filter), non-woven media type filter (such as dry-formed, wet-laid or membrane type filter). 
     The filter may contain filtration material. 
     The filtration material may comprises one or more of: pleated paper, nano fibres, cellulose, cotton, wood pulp, glass, fiberglass, glass micro fiber, or composites, polymers such as polytetrafluoroethylene (PTFE), polycarbonate (PC), acrylics including modacrylics, rayon, fluoropolymers, thermoplastic polyurethane (TPU), polyethylene (PE), polyamides, polyester, polypropylene (PP), nylon, metals such as galvanized steel, stainless steel, aluminium, copper. 
     The composites may consist of: polyamides, polyether sulfone, polysulfone, ceramic, carbon, polymers such as polytetrafluoroethylene (PTFE), polycarbonate (PC), acrylics, rayon, fluoropolymers, thermoplastic polyurethane (TPU), polyethylene (PE), polyamides, polyester, polypropylene (PP), nylon. 
     The filter or a filtration material of the filter may comprise: electrostatic, hydrophilic, hydrophobic characteristics or properties. 
     The patient interface may comprise a nasal cannula or a nasal mask, wherein the nasal cannula or nasal mask comprises at least one gases flow path that is in pneumatic communication with the filter, or that is configured to be placed in pneumatic communication with the filter when the filter is coupled to the patient interface. In some configurations, the nasal cannula comprises at least one nasal delivery element that extends from a flow manifold and that is adapted to rest in one or more nares of a user to deliver humidified gas to the user, whether in a sealing manner or a non-sealing manner. 
     The inspiratory conduit may comprise a heating element to heat humidified gases as they travel through the inspiratory tube. 
     The humidifier chamber may comprise a housing defining a liquid reservoir, a gases inlet port in pneumatic communication with the liquid reservoir, a gases outlet port in pneumatic communication with the liquid reservoir, and a base, wherein the base is arranged to be positioned on or above a heating element to heat liquid in the liquid reservoir, and wherein the gases inlet port, the liquid reservoir, and the gases outlet port provide a gases flow path from the gases inlet port, through or past the liquid reservoir, to the gases outlet port to humidify gases travelling along the gases flow path. 
     The inspiratory conduit may further comprise a component adapted to be engageable with said inspiratory conduit and to support said inspiratory component. 
     The inspiratory conduit may further comprises a component adapted to engage with said inspiratory conduit and provided with jaws extending from a body of the component, the jaws adapted to grip an item and thereby support said inspiratory component. 
     Optionally, the jaws may be a pair of opposing jaws for gripping of an item, such as a sheet or article of clothing or other item or article (e.g. a medical stand or component attached thereto). 
     The body of the component may substantially surround a perimeter of the conduit or tube upon which it is located. 
     The jaws of the component may be co-acting upon each other in a closed position. 
     The body comprises a shoulder portion associated with each jaw of the pair of jaws, the shoulder portion providing a surface for actuation, by a user. 
     The shoulder portion is an enlarged region of the body. 
     The shoulder portions are sized for actuation by fingers of a user, or are finger tabs. 
     The body is configured to be substantially annular about the exterior surface of the, or each, respective tube(s). 
     The component may be a tube clip capable of engaging with an exterior surface or surfaces of a conduit or tube, such as the inspiratory conduit, where the tube clip additionally comprises a pair of jaws adapted for gripping of an item, such that when the jaws of the tube clip grip an item, the conduit or tube may be supported. 
     The component may for example be that as described by PCT/NZ2012/000169 (published as WO2013/073970) the entirety of the contents of which is incorporated herein by reference. 
     The apparatus or kit may be provided as a kit. 
     Additionally, in accordance with certain features, aspects and advantages of at least one of the embodiments disclosed herein, there is provided the apparatus or kit as outlined in relation to the aspect above, when used to deliver humidified gas to a user or patient. In some applications, the patient is being anaesthetized and/or has been anaesthetized and is not breathing spontaneously. In some applications, the patient is being pre-oxygenated prior to being anaesthetized. 
     Additionally, in accordance with certain features, aspects and advantages of at least one of the embodiments disclosed herein, a package is disclosed. The package comprises a sealed container or bag that contains the apparatus or kit as outlined in relation to the aspect above. 
     The filter, the humidifier chamber, the inspiratory conduit, the gases delivery conduit and patient interface may be each provided separately in the package (i.e. not coupled or integrated). Alternatively, at least some of these may be provided in a coupled arrangement together in the package. 
     For example, a first kit may or package may comprise of “consumable” components, such as a gases delivery conduit (i.e. a conduit of the type that extends from a source of gas to the inlet of a humidifier chamber), a humidifier chamber, an inspiratory conduit (i.e. a conduit of the type extends from the outlet or downstream side of a humidifier chamber toward a patient interface), a tube clip (i.e. a component of the type that may be attached or attachable to a conduit, such as an inspiratory conduit to assist with supporting or locating the inspiratory conduit relative to an item), a filter, an adapter insert (i.e. to facilitate connection between components), and a patient interface (i.e. a patient interface of the type such as those described elsewhere in this specification, but which may comprise of a nasal cannula or a nasal mask). It will be appreciated the gases delivery conduit may be of the type referred to as a “dryline”, as it is not downstream of a humidification device, such as a humidifier chamber, which provides humidity to the flow of gases being directed toward a patient interface for a patient. 
     For example, another kit or package may comprise of “patient” components, such “patient” components being provided for use with a single patient, and/or for a single use or procedure. “Patient components” being for example a patient interface and a filter for connection to such an interface. In another kit or package, the patient interface and the filter may be provided in an entirely different or separate package for sale on their own (e.g. a patient interface and filter sold together) or for providing this combination of components to the medical industry. 
     For example, yet another kit or package may comprise of those components required where a patient is not receiving a humidified gas, and as such, a humidifier chamber or a suitable downstream conduit of the type associated with delivering humidified gases is not required. Such a kit or package may comprise of a patient interface, a filter, and a conduit for delivering gas from a source of gas to the patient interface (such a conduit may be a gases delivery conduit or a non-heated inspiratory conduit). 
     The patient interface and filter may be provided separately in the package (i.e. not coupled or integrated). In some configurations, the patient interface and filter are coupled in the package, or the filter is integrated into the patient interface gases tube of the patient interface. 
     Additionally, in accordance with certain features, aspects and advantages of at least one of the embodiments disclosed herein, a method of assembling a breathing circuit is disclosed. The method comprises: providing the apparatus or kit or the package outlined in relation to the aspects above; positioning the inspiratory conduit downstream of the humidifier chamber, and positioning the filter and patient interface downstream of the inspiratory conduit. 
     The method may further comprise receiving gas at the humidifier from the source of gas, humidifying the gas, receiving humidified gas at the filter from the humidifier, and delivering the humidified gas from the filter to the patient interface. 
     The method may further comprise positioning the gases delivery conduit upstream of the humidifier chamber and downstream of the source of gas, prior to receiving gas at the humidifier from the source of gas. 
     The method may further comprise coupling the filter to the patient interface, prior to delivering the humidified gas from the filter to the patient interface. 
     In some applications, the method further comprises decoupling the filter from the humidifier. In some applications, the method further comprises operatively coupling the filter to another source of gas. 
     The method may further comprise, after decoupling the filter from the humidifier, providing a further apparatus or kit comprising a patient interface for delivering humidified gas to a patient and a filter that is in pneumatic communication with the patient interface or that is configured to be placed in pneumatic communication with the patient interface; and positioning the filter and patient interface of the further apparatus downstream of the humidifier. 
     The method may further comprise receiving humidified gas at the filter from the humidifier and delivering the humidified gas from the filter to the patient interface. 
     Additionally, in accordance with certain features, aspects and advantages of at least one of the embodiments disclosed herein, a method of delivering gas to a user or patient is disclosed. The method comprises: providing a breathing circuit comprising a source of gas and the apparatus or kit as outlined in relation the aspect above or the package as outlined in relation to the aspect above, and configuring the breathing circuit such that the humidifier receives gas from a source of gas, the inspiratory conduit is positioned downstream of the humidifier and delivers humidified gas from the humidifier to the filter, and the patient interface is positioned downstream of the filter and receives humidified gas from the filter and delivers humidified gas to the user or patient. 
     The method may further comprise positioning the gases conduit downstream of the source of gas to deliver gas from the source of gas to the humidifier to humidify the gas. 
     In some applications, the patient is not breathing spontaneously and has been anaesthetized. In some applications, the patient is being pre-oxygenated prior to being anaesthetized. 
     Additionally, in accordance with certain features, aspects and advantages of at least one of the embodiments disclosed herein, an apparatus or kit for use in a respiratory support system for delivering humidified gas to a user or patient is disclosed. The apparatus or kit comprises:
         a filter that is positioned downstream of a humidifier to receive humidified gas from the humidifier, or that is configured to be positioned downstream of a humidifier to receive humidified gas from the humidifier; and   a patient interface for delivering humidified gas to a user or patient, wherein the patient interface is in pneumatic communication with the filter downstream of the filter, or is configured to be placed in pneumatic communication with the filter downstream of the filter,   wherein a gases inlet or a gases outlet or both the gases inlet and gases outlet of the filter, comprise coupling features enabling the filter to be coupled and decoupled from an arrangement in which the filter is placed in pneumatic communication with said patient interface.       

     The filter may be coupled to the patient interface, or may be configured to be coupled to the patient interface. 
     The patient interface may comprise a patient interface gases tube, wherein the filter comprises a gases inlet port and a gases outlet port, and wherein the gases outlet port of the filter and the patient interface gases tube comprise complementary coupling features to enable the filter to be coupled to the patient interface to provide pneumatic communication between the filter and the patient interface gases tube, with the filter in-line with a gases flow path through the patient interface gases tube. 
     The complementary coupling features may be disconnectable from each other to enable the filter to be decoupled from the patient interface gases tube of the patient interface. 
     The patient interface may comprise a patient interface gases tube, wherein the filter is integrated into the patient interface gases tube to provide pneumatic communication between the filter and the patient interface gases tube, with the filter in-line with a gases flow path through the patient interface gases. Optionally, in such an arrangement, a gases inlet to such an integrated filter may comprise of complementary coupling features. Such complementary coupling features may for example be provided by an adapter insert attached to the gases inlet of such an integrated filter component. 
     The filter may be a high-efficiency particulate arrestance (HEPA) filter. 
     The filter may comprise a filter housing containing filtration material. The filtration material may comprise pleated paper, nano fibres, sock filter, stacked disc filter, spiral filter, block of filter material, a disc of filter material with streams of filter material to free flow from or off the disc in fluid flow. 
     The patient interface may comprise a nasal cannula or nasal mask, wherein the nasal cannula or nasal mask comprises at least one gases flow path that is in pneumatic communication with the filter, or that is configured to be placed in pneumatic communication with the filter when the filter is coupled to the patient interface. The nasal cannula may comprise at least one nasal delivery element that extends from a flow manifold and that is adapted to rest in one or more nares of a user to deliver humidified gas to the user, whether in a sealing manner or a non-sealing manner. 
     The apparatus or kit may be provided as a kit. 
     Additionally, in accordance with certain features, aspects and advantages of at least one of the embodiments disclosed herein, there is provided the apparatus or kit as outlined in relation to the aspect above, when used to deliver humidified gas to a user or patient. In some applications, the patient is being anaesthetized and/or has been anaesthetized and is not breathing spontaneously. In some applications, the patient is being pre-oxygenated prior to being anaesthetized. 
     Additionally, in accordance with certain features, aspects and advantages of at least one of the embodiments disclosed herein, a package is disclosed. The package comprises a sealed container or bag that contains the apparatus or kit as outlined in relation to the aspect above. 
     The patient interface and filter m provided separately in the package. 
     The patient interface and filter may be coupled in the package, or wherein the filter is integrated into with the patient interface gases tube. 
     Additionally, in accordance with certain features, aspects and advantages of at least one of the embodiments disclosed herein, a method of assembling a breathing circuit is disclosed. The method comprises providing the apparatus or kit as outlined in relation to the aspect above or the package as outlined in relation to the aspect above; and positioning the filter and patient interface downstream of a humidifier. 
     The method may further comprise receiving humidified gas at the filter from the humidifier and delivering the humidified gas from the filter to the patient interface. 
     The method may further comprise coupling the filter to the patient interface, prior to delivering the humidified gas from the filter to the patient interface. 
     The method may comprise decoupling the filter from the humidifier. In some applications, the method further comprises operatively coupling the filter to another source of gas. 
     The method may comprise after decoupling the filter from the humidifier, providing a further apparatus or kit or package as outlined in relation to the aspects above; and positioning the filter and patient interface of the further apparatus downstream of the humidifier. 
     The method may further comprise receiving humidified gas at the filter from the humidifier and delivering the humidified gas from the filter to the patient interface. 
     Additionally, in accordance with certain features, aspects and advantages of at least one of the embodiments disclosed herein, a method of delivering gas to a user or patient is disclosed. The method comprises: providing a breathing circuit comprising a source of gas, a humidifier that receives gas downstream from the source of gas, and the apparatus or kit or the package as outlined in relation to the aspects above, and configuring the breathing circuit such that the filter is positioned downstream of the humidifier and receives humidified gas from the humidifier, and the patient interface is positioned downstream of the filter and receives humidified gas from the filter and delivers humidified gas to the user or patient. 
     In some applications, the patient is not breathing spontaneously and has been anaesthetized. In some applications, the patient is being pre-oxygenated prior to being anaesthetized. 
     Additionally, in accordance with certain features, aspects and advantages of at least one of the embodiments disclosed herein, a respiratory support system is disclosed. The respiratory support system comprises either:
         an inspiratory conduit having an inlet port and an outlet port, the inlet port being configured to receive gas from a source of gas; a filter having an inlet port and an outlet port, wherein the inlet port of the filter is coupled to the outlet port of the inspiratory conduit such that the filter is in pneumatic communication with the inspiratory conduit; and a patient interface, the patient interface comprising a patient conduit and a nasal cannula or a nasal mask for delivering gas to a patient, wherein the patient interface, is in pneumatic communication with the outlet port of the filter to receive gas from the outlet port of the filter, or   a single inspiratory conduit having an inlet port and an outlet port, the single inspiratory conduit providing for a flow of gas for delivery to a patient interface, the inlet port being configured to receive the flow of gas from a source of gas; a common filter having an inlet port and an outlet port, wherein the inlet port of the common filter is coupled to the outlet port of the single inspiratory conduit such that the common filter is in pneumatic communication with the single inspiratory conduit, and wherein the common filter received the flow of gas from the single inspiratory conduit; and a patient interface, the patient interface comprising a patient conduit and a nasal cannula or a nasal mask for delivering gas to filtered by the common filter to a patient, wherein the patient interface is in pneumatic communication with the outlet port of the common filter to receive gas from the outlet port of the common filter.       

     The filter may be in-line between the outlet port of the inspiratory conduit and the patient conduit, or the common filter is in-line between the outlet port of the single inspiratory conduit and the patient conduit. 
     In this specification, where an inspiratory conduit may be provided or reference is made thereto, such an inspiratory conduit may be a single inspiratory conduit. Such an inspiratory conduit providing for a flow of gas for delivery to a patient interface. 
     In this specification, where a filter may be provided or reference is made thereto, such a filter may be a common filter for filtering the flow of gas supplied from an inspiratory conduit. Such a common filter receives the flow of gas from an inspiratory conduit, such as a single inspiratory conduit. Accordingly, the gas delivered to the patient interface is provided from the common filter. 
     The patient conduit may comprise a patient interface gases conduit, wherein the filter (e.g. a common filter) is in-line with the patient interface gases conduit. 
     The inlet port of the inspiratory conduit (e.g. being a single inspiratory conduit) may be configured to receive humidified gas from a humidifier. 
     Additionally, in accordance with certain features, aspects and advantages of at least one of the embodiments disclosed herein, a kit for use in a respiratory support system for delivering humidified gas to a user or patient is disclosed, The kit comprises: a humidifier chamber that is configured to be placed in pneumatic communication with a gases source;
         an inspiratory conduit that is in pneumatic communication with the humidifier chamber downstream of the humidifier chamber, or that is configured to be placed in pneumatic communication with the humidifier chamber downstream of the humidifier chamber;   a filter that is in pneumatic communication with the inspiratory conduit downstream of the inspiratory conduit, or that is configured to be placed in pneumatic communication with the inspiratory conduit downstream of the inspiratory conduit; and   a patient interface for delivering humidified gas to a user or patient, wherein the patient interface is in pneumatic communication with the filter downstream of the filter, or is configured to be placed in pneumatic communication with the filter downstream of the filter.       

     The filter may be integrated into the patient interface. Optionally, in such embodiments, an adapter insert may be provided to a gases inlet of the filter, such an adapter insert may for example be of the type described elsewhere in this specification. 
     The kit may further comprise a gases delivery conduit that is configured to be placed in pneumatic communication with the source of gas, wherein the humidifier chamber is in pneumatic communication with the gases delivery conduit downstream of the gases delivery conduit, or is configured to be placed in pneumatic communication with the gases delivery conduit downstream of the gases delivery conduit. 
     At least some of the components of the kit may be provided separately in the kit. 
     Additionally, in accordance with certain features, aspects and advantages of at least one of the embodiments disclosed herein, a kit for use in a respiratory support system for delivering humidified gas to a user or patient is disclosed. The kit comprises:
         a filter that is configured to be positioned downstream of a humidifier to receive humidified gas from the humidifier; and   a patient interface for delivering humidified gas to a patient, wherein the patient interface is in pneumatic communication with the filter downstream of the filter, or is configured to be placed in pneumatic communication with the filter downstream of the filter.       

     The filter may be integrated into the patient interface. 
     Additionally, in accordance with certain features, aspects and advantages of at least one of the embodiments disclosed herein, an apparatus or kit for use in a respiratory support system for delivering humidified gas to a user or patient is disclosed, the apparatus or kit comprising:
         a gases delivery conduit that is in pneumatic communication with a source of gas, or that is configured to be placed in pneumatic communication with the source of gas;   a humidifier chamber that is in pneumatic communication with the gases delivery conduit downstream of the gases delivery conduit, or that is configured to be placed in pneumatic communication with the gases delivery conduit downstream of the gases delivery conduit; and   an inspiratory conduit that is in pneumatic communication with the humidifier chamber downstream of the humidifier chamber, or that is configured to be placed in pneumatic communication with the humidifier chamber downstream of the humidifier chamber.       

     Additionally, in accordance with certain features, aspects and advantages of at least one of the embodiments disclosed herein, a kit for use in a respiratory support system for delivering humidified gas to a user or patient is disclosed, the kit comprising:
         a gases delivery conduit that is configured to be placed in pneumatic communication with a source of gas;   a humidifier chamber that is in pneumatic communication with the gases delivery conduit downstream of the gases delivery conduit, or that is configured to be placed in pneumatic communication with the gases delivery conduit downstream of the gases delivery conduit; and   an inspiratory conduit that is in pneumatic communication with the humidifier chamber downstream of the humidifier chamber, or that is configured to be placed in pneumatic communication with the humidifier chamber downstream of the humidifier chamber.       

     The apparatus or kit, the package, the respiratory support system, or the kit, may be configured for use in anaesthetic procedures or procedures wherein a patient&#39;s respiratory drive is compromised or reduced. 
     Each apparatus or kit may be provided on its own or together. Different types of kits may be provided together or separately. For example, a single package may be provided with two or more of the kits of the same or different types therein. 
     Additionally, either provided independently or in accordance with certain features, aspects and advantages of at least one of the embodiments disclosed herein, there is provided a filter arrangement. 
     The filter arrangement may comprise a filter housing, the filter housing comprising a gases inlet port and a gases outlet port, wherein at least one (or both) of said inlet and/or outlet port(s) is adapted for connection with another component (such as a connector provided at a terminal end of a conduit) via one or more, preferably at least a pair, of male connection fingers extending externally therefrom. Optionally, such male connection fingers may provide for a part of a complementary coupling. 
     The male connection fingers may be configured to extend from said gases outlet port. Optionally, or alternatively, said male connection fingers may be configured to extend from said gases inlet port. 
     One or each of said gases inlet port or gases outlet port may comprise an adapter insert, said adapter insert configured to facilitate said connection with said another component. 
     The adapter insert may comprise said male connection fingers extending from a first end of the adapter insert. 
     The adapter insert may comprise one or more retention members, each said retention member substantially engageable with an interior surface portion of the filter housing. 
     Each retention member may be configured for an engagement with an interior surface of the filter housing to retain said adapter insert within a said port into which said adapter is inserted. 
     Each said retention member may be configured to resist axial displacement of said adapter in a direction toward an exterior end of a said port. 
     Each said retention member may comprise at least a hook or other surface projection (e.g. such as a radially outwardly extending ledge) to engage or latch with an internal surface of said filter housing. 
     The or each retention member may retain said adapter insert within a said port of the filter housing. 
     There may be four retention members, or there may be two retention members, or there may be a plurality of retention members. 
     Where there is provided more than one retention member, said retention members may be are arranged to form an array about an interior surface of the filter housing. 
     The adapter insert may comprise of a first end from which said male connection fingers extend, a second end from which the one or more retention members extend, and a shank portion connecting of the first end with the second end. 
     The shank portion may comprise a lumen or gas flow path for the passage of gases therethrough between each of the first end and second end. 
     The shank portion may be substantially housed within a said port into which said adapter insert is to be inserted. 
     The adapter insert may comprise one or more sealing members. 
     The adapter insert may comprise two or more sealing members. 
     The adapter insert may comprise two sealing members. 
     The adapter insert may comprises at least a first sealing member provided about the shank portion and at least a second sealing member provided substantially at or adjacent with a first end of the adapter insert. 
     At least one first sealing member may be provided about the shank portion. 
     The or a first sealing member may be provided about a circumference of the shank portion. 
     The or each said first sealing member may be configured to provide a first sealing surface extending radially outwardly from the shank portion. 
     The or each said first sealing member may be configured to provide a first sealing surface for sealing with an internal surface of a said port of the filter housing. 
     The or each said first sealing member may be located intermediate of a first end and a second end of the adapter insert. 
     At least one second sealing member may be provided substantially at or adjacent with a first end of the adapter insert. 
     The at least one second sealing member may be located substantially at or adjacent with a base of the male connection fingers as said male connection fingers extend from a first end of the adapter insert. 
     The first end of the adapter insert may comprise a radially extensive ledge or lip. 
     The at least one second sealing member may be located substantially upon an upper-side surface of the ledge or lip. 
     The ledge or lip may extend radially outwardly so as to have an outside diameter that is equal to or less than the outside diameter of a said port within which said adapter insert is to be located. Advantageously, the ledge or lip may be of an outside diameter that is greater than an inside diameter of a said port within which said adapter insert is to be located. 
     An underside surface of said ledge or lip may contact a terminal end face of a said port within which said adapter insert is to be located. 
     A distance between an underside surface of the ledge or lip and a retaining member may match or may be substantially equal to a length of a said port from said adapter insert into which said adapter insert is to be located. 
     The ledge or lip may be interposed or may be sandwiched between an end of the shank portion and a first end of the adapter insert. 
     The ledge or lip may be sandwiched between a base of said male connection fingers and an end of the shank portion. 
     The at least one second sealing member may be sandwiched between a base of said male connection fingers and an end of the shank portion. 
     The at least one second sealing member may be sandwiched between a base of said male connection fingers and an upper-side surface of the ledge or lip. 
     The at least one second sealing member may provide for a second sealing surface for sealing with a surface of another component (such as another connector) brought to bear upon said second sealing surface. Optionally, said another component (such as another connector) may be brought into connection or engagement with said male connection fingers and, in use, when such a connection or engagement is made, said another component may additionally engage with said second sealing member and said second sealing surface may be configured to operatively assist with a pneumatic connection between said adapter insert and said another component. 
     Either or both of the first and second sealing members may be an O-ring. 
     One or more splines or ribs may be located about the shank portion. 
     The one or more splines or ribs may extend longitudinally along the shank portion. 
     The one or more splines or ribs may extend a radial distance outward from the shank portion so as to at least partially engage or make surface contact with an inside surface of a said port into which said adapter insert is to be located. 
     One or each of the one or more splines or ribs may be configured to provide strengthening or structural support of a wall of a said port into which said adapter insert is to be located. 
     Exclusive of the first sealing member(s), said adapter insert may have a maximum radial outside diameter of equal to or less than 22 mm. 
     The lumen or gas flow path may transition from a substantially wider bore (or larger internal diameter) at a second end of the adapter insert to a substantially narrower bore (or a smaller internal diameter) at a first end of the adapter insert. 
     The lumen or gas flow path transition may be a substantially graduated, or a substantially linear, progression between the different bores or internal diameters between end of the first and second ends. 
     The adapter insert may be a retro-fittable piece, locatable with or insertable to a component to facilitate provision of the male connection fingers as a connecting system or connector for the component to which the adapter is inserted or located therewith. 
     Additionally, either provided independently or in accordance with at least one of the other embodiments disclosed herein, an adapter insert is disclosed. 
     The adapter insert comprises one or more (but may be at least a pair of), male connection fingers configured for connection or engagement with another connector, and one or more retention members, each said retention member to be substantially engageable with an interior surface portion of a body of a component into which said adapter insert is to be located. 
     The adapter insert may be configured to be located within a gases inlet port or a gases outlet port of a component, such as a connector provided at an end of a conduit or an inlet or outlet from another component such as, but not limited to, a humidifier or a flow source generator. 
     An off-the-shelf type filter may be adapted by insertion of the adapter insert as described in this specification. Retention members of the adapter insert facilitate an intended retention of the adapter insert in an inserted location with respect to a port (whether as an inlet or an outlet port) of such a filter. 
     Where a component has a gases inlet port or a gases outlet port, such a port may comprise the adapter insert, said adapter insert configured to facilitate engagement or connection with another component (e.g. a filter). 
     Optionally, the filter or a filter arrangement comprises a filter housing, the filter housing comprising a gases inlet port and a gases outlet port, wherein at least one (or both) of said inlet and/or outlet port(s) is adapted for connection with another component (such as a connector provided at a terminal end of a conduit) via said male connection fingers of said adapter insert, when said adapter insert is located within a said port. 
     The male connection fingers of the adapter insert may be configured to extend (externally therefrom) from a gases outlet port or gases inlet port of a said component. 
     The male connection fingers may extend from a first end of the adapter insert. 
     Each said retention member may be configured to be substantially engageable with an interior surface portion of said component into which said adapter insert is to be located. 
     Each retention member may be configured for an engagement with an interior surface of the component to retain said adapter insert within a said port into which said adapter insert is to be inserted. 
     Each said retention member may resist axial displacement of said adapter insert in a direction toward an exterior end of a said port of said component (e.g. said retention members help to resist an unintended disconnection of the adapter insert from a component to which it is or has been inserted or located thereto). 
     Each said retention member may be configured to internally locate said adapter insert into an internally anchored position within a said component. 
     Each said retention member may comprise at least a hook or other surface projection (e.g. such as a radially outwardly extending ledge) to engage or latch with an internal surface of a said component. 
     The or each retention member may retain said adapter insert within a said port of a said component. 
     There may be four retention members, or there may be two retention members, or there may be one, or there may be a plurality of retention members. 
     Where more than one retention members are provided, at least some of said retention members may be arranged to form an array about an interior surface of a said component. 
     The adapter insert may comprise of a first end from which said male connection fingers extend, a second end from which the one or more retention members extend, and a shank portion connecting of the first end with the second end. 
     The shank portion may comprise a lumen or gas flow path for the passage of gases therethrough between each of the first end and second end. 
     The shank portion may be substantially housed within a said port of a component into which said adapter insert is to be inserted. 
     The adapter insert may comprise one or more sealing members. 
     The adapter insert may comprise two or more sealing members. 
     The adapter insert may comprise two sealing members. 
     The adapter insert may comprise at least a first sealing member provided about the shank portion and at least a second sealing member provided substantially at or adjacent with a first end of the adapter insert. 
     At least one first sealing member may be provided about the shank portion. 
     The or a first sealing member may be provided about a circumference of the shank portion. 
     The or each said first sealing member may be configured to provide a first sealing surface extending radially outwardly from the shank portion. 
     The or each said first sealing member may be configured to provide a first sealing surface for sealing with an internal surface of a said port of a component. 
     The or each said first sealing member may be located intermediate of a first end and a second end of the adapter insert. 
     At least one second sealing member may be provided substantially at or adjacent with a first end of the adapter insert. 
     The at least one second sealing member may be located substantially at or adjacent with a base of the male connection fingers as said male connection fingers extend from a first end of the adapter insert. 
     The first end of the adapter insert may comprise a radially extensive ledge or lip. 
     The at least one second sealing member may be located substantially upon an upper-side surface of the ledge or lip. 
     The ledge or lip may extend radially outwardly so as to have an outside diameter that is equal to or less than the outside diameter of a said port of a component within which said adapter insert is to be located. Advantageously, the ledge or lip may be of an outside diameter that is greater than an inside diameter of a said port of a component within which said adapter insert is to be located. 
     An underside surface of said ledge or lip may contact a terminal end face of a said port of a component within which said adapter insert is to be located. 
     A distance between an underside surface of the ledge or lip and a retaining member may matches or may be substantially equal to a length of a said port of a component from said adapter insert is to be located. 
     The ledge or lip may be interposed or is sandwiched between an end of the shank portion and a first end of the adapter insert. 
     The ledge or lip may be sandwiched between a base of said male connection fingers and an end of the shank portion. 
     The at least one second sealing member may be sandwiched between a base of said male connection fingers and an end of the shank portion. 
     The at least one second sealing member may be sandwiched between a base of said male connection fingers and an upper-side surface of the ledge or lip. 
     The at least one second sealing member may provide for a second sealing surface for sealing with a surface of another component (such as another connector) brought to bear upon said second sealing surface. Optionally, said another component (such as another connector) may be brought into connection or engagement with said male connection fingers and, in use, when such a connection or engagement is made, said another component may additionally engage with said second sealing member and said second sealing surface may be configured to operatively assist with a pneumatic connection between said adapter insert and said another component. 
     Either or both of the first and second sealing members may be an O-ring. 
     One or more splines or ribs may be located about the shank portion. 
     The one or more splines or ribs may extend longitudinally along the shank portion. 
     The one or more splines or ribs may extend a radial distance outward from the shank portion so as to at least partially engage or make surface contact with an inside surface of a said port of a component into which said adapter insert is to be located. 
     One or each of the one or more splines or ribs may be configured to provide strengthening or structural support of a wall of a said port of a component into which said adapter insert is to be located. 
     Exclusive of the first sealing member(s), said adapter insert may have a maximum radial outside diameter of equal to or less than 22 mm. 
     The lumen or gas flow path may transition from a substantially wider bore (or larger internal diameter) at a second end of the adapter insert to a substantially narrower bore (or a smaller internal diameter) at a first end of the adapter insert. 
     The lumen or gas flow path transition may be a substantially graduated, or a substantially linear, progression between the different bores or internal diameters between end of the first and second ends. 
     The component as referred to above may be a filter, for example a filter as previously defined herein. 
     The another component may be a connector provided as a part of another section of a medical breathing circuit or a respiratory system. 
     According to any one or more of the embodiments described herein, the following additional features may be provided: 
     For example, where reference is made to a patient interface, such an interface may be a nasal cannula or a nasal mask. 
     For example, the apparatus described herein may be provided as a part of a system that comprises a gas supply which may be coupled to the apparatus to supply gas to a patient interface or other components associated with a breathing circuit or respiratory therapy system. 
     The gas supply may be configured to supply gas to a humidifier at a flow rate of between about 5 liters per minute (LPM) and about 120 LPM, or up to about 150 LPM, or at a flow rate of between about 50 LPM and about 80 LPM, or at a flow rate of about 70 LPM. In some configurations, the humidifier may be configured to supply gas to a patient interface with a humidity of about 44 mg/l. 
     The humidifier may be configured to supply gas to the patient interface with a temperature of about 37° C. 
     According to the various configurations or embodiments as disclosed in this specification, the patient interface may be a nasal cannula type or nasal mask type interface comprising a gas delivery component in the form of a manifold, the manifold being removably attachable to the body of the nasal cannula or nasal mask. 
     The removably attachable manifold may allow for a side swapping of the gas delivery conduit supply gas to the patient interface. The manifold may be of a push-fit type arrangement or may be connected to the body, yet disconnectable so as to allow for a swivelling or rotation of the manifold relative to the body for a re-orientation of the manifold and an associated gas supply conduit. 
     A patient interface which may be utilised according to the various embodiments described in this disclosure may be of the type that utilise a headgear comprising of at least one strap, such as a strap including a bifurcatable section or zone (i.e. a line of weakness or other pre-determined region able to be split by a user). 
     The tubing, which also may also be referred to herein as a conduit, or tubing or conduit circuits described herein is or are in the preferred form made of medical tubing or medical grade tubing suitable for use in medical procedures and/or as a part of a breathing circuit or respiratory therapy circuit. 
     The adapter insert as described herein may be utilised in combination with the filter as described elsewhere in this specification (e.g. the gas inlet or outlet of a filter), or for an adaptation to the terminal end of a conduit, for example with a connector provided at such a terminal end of a conduit. The adapter insert may facilitate connection by other components to a filter or a conduit which otherwise were not provided with a suitably configured connector. Accordingly, the insert allows for an adaptation not only of the component to which it is to be attached, but provides for an adapted connector capable of being connected to by still other components. 
     As relatively high gas delivery flow rates may be used with the embodiments or configurations described herein, the gases being supplied or delivered to the user or patient may be delivered to different parts of the user&#39;s or a patient&#39;s airway. The gases being supplied may reach the patient&#39;s lungs or any part of the respiratory system. 
     For example, according to those various embodiments and configurations described herein, a flow rate of gases supplied or provided to an interface or via a system, such as through a flow path, may comprise, but is not limited to, flows of at least about 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, or 150 liters per min (LPM), or more, and useful ranges may be selected between any of these values (for example, about 40 to about 80, about 50 to about 80, about 60 to about 80, about 70 to about 80 LPM). Optionally, the gases supplied may be delivered in a fully saturated or humidified condition, or a saturated or humidified gas may be blended with other gases for supply or delivery to a patient interface or the patient. 
     Such relatively high flow rates of gases may assist in providing the supplied gases into a user&#39;s airway, or to different parts of a user&#39;s airway, for example such flow rates may allow for a delivery of such gases to the upper or lower airway regions. Upper airway region typically includes the nasal cavity, pharynx and larynx, while the lower airway region typically includes the trachea, primary bronchi and lungs. 
     It would be desirable to provide a system in which the humidity and temperature of the gas reach an ideal gas condition, for example, about 37° C. and about 44 mg/l as quickly as possible, and tubing for such systems. 
     In accordance with at least one of the embodiments disclosed herein, there is provided a connector for connecting a breathing circuit to a patient interface comprises a filter. 
     The connector may comprise a one way valve. 
     In accordance with at least one other embodiment disclosed herein, there is provided a connector for connecting a breathing circuit to a patient interface comprises a filter provided in pneumatic connection with a one-way valve. 
     In the connector, the filter is one of a HEPA filter, sock filter, stacked disc filter, spiral filter, pleated sheet filter, block of filter material, nano fibre filter, a disc of filter material with streams of filter material to free flow from or off the disc in fluid flow. 
     In the connector, the one way valve may open in response to an application of a flow applied or directed toward the patient interface through said breathing circuit and may close or shut in response to an application of no flow applied or directed toward the patient interface through said breathing circuit. 
     In the connector, the filter may be attached to an outlet of the one way valve. 
     In the connector, the one way valve may be a duckbill valve. 
     In the connector, the filter may comprise an expanding filter material, the expanding filter material attached to the duckbill end of the duckbill valve, so that as the valve opens the filter material expands to allow flow through the valve and filter material. 
     The connector may be a reducing union or socket or adapter. 
     In the connector, the filter is formed from a filter material comprising one or more of mineral fibres, glass fibres, ceramic fibres, polypropylene, expanded polytetrafluoroethylene, modacrylic and Estane®, cellulose fibres, or electrostatic fibres. 
     The filter may be hydrophobic. 
     The filter may be hydrostatic. 
     The filter may allow air and water vapour to pass through. 
     The connector may be provided as a single use item. 
     In accordance with at least one of the embodiments disclosed herein, there is provided a breathing circuit comprising a filter. Optionally, a conduit of the breathing circuit may comprise the filter. The filter may be located at or adjacent an end of the conduit. The filter may comprise one or more features as described above in relation to a connector comprising a filter. 
     In accordance with at least one of the embodiments disclosed herein, a filter for a respiratory breathing circuit and/or a patient interface is one of a HEPA filter, sock filter, stacked disc filter, spiral filter, pleated sheet filter, nano fibre filter, block of filter material, a disc of filter material with streams of material to free flow from or off the disc in fluid flow, the filter adapted to be fitted into a patient interface or breathing circuit conduit. 
     According to the embodiments above, the filter may be formed from a filter material comprising one or more of mineral fibres, glass fibres, ceramic fibres, polypropylene, expanded polytetrafluoroethylene, modacrylic and Estane®, cellulose fibres, or electrostatic fibres. 
     The filter may be hydrophobic. 
     The filter may be hydrostatic. 
     The filter may allow air and water vapour to pass through. 
     The connector may be provided as a single use item. 
     In accordance with at least one of the embodiments disclosed herein, there is provided a patient interface tube that comprises an open cell foam material with a sealing skin, such that the patient interface tube is breathable in that it allows water vapour to pass through the material and sealing skin, but does not allow the passage of liquid water or bulk flow of gases therethrough. The interface tube providing a tube or conduit for the gases flow to be provided from a breathing circuit to a patient interface. 
     In accordance with at least one of the embodiments disclosed herein, there is provided a nasal cannula comprising one or two nasal prongs to fit into a patient&#39;s nostrils, each nasal prong providing a filter for a flow of gases from the patient interface to a patient. 
     In accordance with at least one of the embodiments disclosed herein, there is provided a filter and valve arrangement for a respiratory breathing circuit that comprises a one way valve and a filter attached to an outlet of the one way valve. 
     The one-way valve may be a duckbill valve. 
     The filter may comprise an expanding filter material, the expanding filter material attached to the duckbill end of the duckbill valve, so that as the valve opens the filter material expands to allow flow through the valve and filter material. 
     In accordance with at least one of the embodiments disclosed herein, there is provided a method for preventing contamination of a breathing circuit for use by more than one patient, the method comprising installing a filter in the breathing circuit or patient interface to prevent contamination of the breathing circuit for use by multiple patients. 
     In accordance with at least one of the embodiments disclosed herein, there is provided a method for preventing contamination of a breathing circuit for use by more than one patient, the method comprising disinfecting a breathing conduit or tube of the breathing circuit using a disinfectant, wherein the disinfectant comprises one or more of (in liquid or gas form) ortho-phthalaldehyde, glutaraldehyde, hydrogen peroxide, and nitrogen dioxide. 
     The disinfectant may be distributed into a breathing conduit or tube from a disinfection reservoir that releases disinfectant when the circuit is not in use on a patient. 
     The method may further use a disinfection capsule that caps an end of the breathing circuit. 
     The capsule may comprise a push button for release of disinfectant. 
     The capsule may be built into the breathing circuit or a separate component that a user inserts into an end of the breathing circuit. 
     The disinfection reservoir may be provided in the walls of a conduit of the breathing circuit or a connector of the breathing circuit, and may be released through one way valves into the breathing circuit via a release mechanism. 
     The release mechanism may be actuated by a signal that is generated when a patient interface is removed from the circuit. For example, the signal may be an electric signal, mechanical signal, or a magnetic signal. 
     A flushing disinfection unit may be attached to each end of the breathing circuit and may alternate between flushing the circuit with water or disinfectant. 
     In accordance with at least one of the embodiments disclosed herein, there is provided a disinfectant capsule for disinfecting a breathing circuit that comprises a reservoir and a release mechanism for releasing disinfectant into the breathing circuit. 
     The capsule may form a cap for capping the end of a breathing tube or conduit of the breathing circuit. 
     The release mechanism may comprise a push button for release of disinfectant. 
     The capsule may be built into the breathing circuit or a separate component that a user inserts into an end of the breathing circuit. 
     A signal may be generated when a patient interface is removed from the circuit to actuate the release of the disinfectant. Such a signal may be an electric signal, mechanical signal, or a magnetic signal. 
     In accordance with at least one of the embodiments disclosed herein, there is provided a breathing circuit that comprises a reservoir in the walls of a tube or conduit of the breathing circuit for holding a volume of disinfectant, and one or more valves between the reservoir and a lumen of the breathing circuit, in use the disinfectant released or releasable from the reservoir into the breathing circuit via actuation of the valves. 
     The breathing circuit may comprise a release mechanism for actuating the valves to release the disinfectant. 
     A signal can be generated when a patient interface is removed from the circuit to actuate the release of the disinfectant. Such a signal may be an electric signal, mechanical signal, or a magnetic signal. 
     In accordance with at least one of the embodiments disclosed herein, there is provided a method for preventing contamination of a breathing circuit for use by more than one patient, the method comprising attaching a flushing disinfection unit to each end of the breathing circuit and using the unit to alternately flush the circuit with water and disinfectant. 
     In accordance with at least one of the embodiments disclosed herein, there is provided a method for preventing contamination of a breathing circuit for use by more than one patient, the method comprising providing radiation (for example, ultraviolet light or near infrared ultra-short pulsed laser) to the breathing circuit to inactivate microorganisms. 
     The method may comprise delivering a sheet of radiation at a connection point between a breathing circuit and a patient interface. 
     The radiation may be delivered to the breathing circuit continuously, including during use of the circuit by a patient. 
     The radiation may be delivered to the breathing circuit only when a patient interface is disconnected (from said breathing circuit). 
     In accordance with at least one of the embodiments disclosed herein, there is provided a connector or conduit of a breathing circuit that comprises a radiation source to prevent contamination of the breathing circuit for use by more than one patient. 
     The radiation source may provide a sheet of radiation at a connection point for connecting a patient interface to the breathing circuit. 
     The radiation source may provide individual beams of radiation or sheets of radiation throughout the circuit. 
     In accordance with at least one of the embodiments disclosed herein, there is provided a humidifier or other hardware of a respiratory breathing system upstream of a breathing circuit that connects with an end of the breathing circuit that comprises a radiation source, the radiation source providing radiation to the breathing circuit to prevent contamination of the breathing circuit for use by more than one patient. 
     In accordance with at least one of the embodiments disclosed herein, there is provided a method for preventing contamination of a breathing circuit including increasing heat in the breathing circuit for a period of time between patients (with or without the gas flow running) to kill microorganisms. 
     The method may comprise increasing the heat output of a heating element in the breathing circuit for said period of time. 
     A disinfection unit may be attached to each end of the breathing circuit and used to cycle hot water (e.g. at 90° C.) and detergent through the breathing circuit for said period of time. The disinfection unit may be a separate unit or may be built-in with any other hardware (for example, a humidifier) upstream of the breathing circuit. 
     A heated collar may be provided at a connection point between the breathing circuit and a patient interface to stop infectious matter migration from the patient into the breathing circuit. 
     In accordance with at least one of the embodiments disclosed herein, there is provided a breathing circuit that comprises a tube or conduit or other component in contact with respiratory gases that is formed from a plastics material with one or more antimicrobial additives. 
     The additives may be one or more of silver and silver based additives (colloidal silver, silver salts, silver zeolite, nano silver), siloxane based additives, Triclosan, and copper. 
     The breathing circuit may comprise a collar around an end or connection point of the breathing circuit where a patient interface is attached or attachable, the collar formed from said material with one or more antimicrobial additives. 
     The or an entire breathing circuit may be made with antimicrobial additives, for example a breathing tube or conduit may be made from a plastics material including antimicrobial additives. 
     In accordance with at least one of the embodiments disclosed herein, there is provided a breathing circuit that comprises a cap for covering an end of the breathing circuit to prevent contamination of the breathing circuit. 
     The cap may be built into the breathing circuit and may be activated by a signal to cover the end of the breathing circuit. For example, the signal may be an electrical, mechanical or magnetic signal generated when the patient interface is removed or unplugged from the breathing circuit. 
     The breathing circuit may include a pressure relief system or stop flow system to prevent over pressure in the breathing circuit when the cap is covering the end of the breathing circuit. 
     The cap may comprise a pressure release mechanism. 
     The cap may comprise a relief valve. 
     In accordance with at least one of the embodiments disclosed herein, there is provided a breathing circuit that comprises an orifice to create a fast flow through the orifice to prevent infectious matter travelling back into the breathing circuit against the direction of flow through the orifice. 
     The orifice may be configured to provide a Peclet number greater than 1, or 10, or 100, or 1000. 
     In accordance with at least one of the embodiments disclosed herein, there is provided a breathing circuit, or a patient interface, or a connector for connecting a breathing circuit to a patient interface, that comprises a one way valve, to prevent contamination from patients entering the breathing circuit. 
     The valve may be one of a duckbill valve, an umbrella valve, a check ball valve, or a constant velocity valve. 
     The valve may be inspiratory triggered, so that gas flow passes through the valve only during inspiration when a pressure differential across the valve allows the valve to open. 
     The breathing circuit may include a pressure relief system to ensure the breathing circuit is not over pressurized. 
     In accordance with at least one of the embodiments disclosed herein, there is provided a method for preventing contamination of a breathing circuit for use by more than one patient, the method comprising providing a one valve to a breathing circuit or patient interface to prevent contamination from patients entering the breathing circuit. 
     The valve may be one of a duckbill valve, an umbrella valve, a check ball valve, or a constant velocity valve. 
     The valve may be provided as a separate element to be inserted into or attached to a conduit and/or patient interface. 
     In accordance with at least one of the embodiments disclosed herein, there is provided a method for preventing contamination of a breathing circuit for use by more than one patient, the method comprising providing a flow of respiratory gases through the breathing circuit to a patient at a first flow rate during an operating mode, and providing a flow of respiratory gases through the breathing circuit at a second flow rate during a non-operating mode, wherein the first flow rate is higher than the second flow rate. The flow along the breathing circuit at the second flow rate being sufficient for preventing or reducing contamination entering the breathing circuit. 
     The first flow rate may be about 70 L/min and the second flow rate may be about 10 L/min. 
     A flow source may provide a flow of respiratory gases to the breathing circuit, or other hardware of a respiratory breathing system upstream of the breathing circuit, the flow source comprising a switch that allows the flow to be switched from the first flow rate in an operational mode to the second flow rate in a non-operational mode. 
     An item of equipment upstream of the breathing circuit, such as a flow source, may include an electrical connection that initiates the second flow when a flow source is connected to the breathing circuit and/or when a patient interface is disconnected from the breathing circuit. 
     An item of equipment upstream of the breathing circuit, such as a flow source, may include an electrical connection that initiates the second flow when the breathing circuit is connected to a patient interface. 
     An item of equipment upstream of the breathing circuit, such as a flow source, may include a mechanical switch (e.g. push valve) that allows different sized orifice openings to be introduced to the flow path to switch between the first and second flow rates. 
     In accordance with at least one of the embodiments disclosed herein, there is provided a breathing circuit, or a patient interface, or a connector for connecting a breathing circuit to a patient interface, that comprises a mesh of hydrophobic material at a connection point between the patient interface and the respiratory breathing circuit, the mesh adapted to prevent contamination from patients entering the breathing circuit. 
     The breathing circuit may comprise a conduit and the mesh is provided at an end of the conduit. 
     The patient interface may include an inlet for connecting to the breathing circuit and the mesh is provided in the inlet. 
     The mesh may be hydrophobic. 
     The mesh may have a pore size that allows flow through the mesh at an operational flow rate and an operating pressure to the patient interface, but which does not allow (or prevents) exhaled breath from the patient to pass through the mesh, a pressure (or flow rate) of the exhaled breath being too low for exhaled breath to pass through the mesh. 
     The mesh may have a pore size to allow an operational flow rate of about 70 L/min to pass from the breathing circuit to the patient. 
     As relatively high gas delivery flow rates may be used with the embodiments or configurations described herein, the gases being supplied or delivered to the patient may be delivered to different parts of the patient&#39;s airway. 
     The filter as described here, or components to be associated with the filter, may be adapted by connection of an adapter insert, the adapter insert may be that as described elsewhere in this specification. 
     For example, according to those various embodiments and configurations described herein, a flow rate of gases supplied or provided to an interface or via a system, such as through a breathing circuit, may comprise, but is not limited to, flows as defined by the high gas delivery flow rates described previously herein. 
     Such relatively high flow rates of gases may assist in providing the supplied gases into a patient&#39;s airway, or to different parts of a patient&#39;s airway. For example, such flow rates may allow for a delivery of such gases to the upper or lower airway regions. Upper airway region typically includes the nasal cavity, pharynx and larynx, while the lower airway region typically includes the trachea, primary bronchi and lungs. 
     Certain features, aspects and advantages of some configurations of the present disclosure have been described with reference to respiratory breathing circuits for use alongside or together with anaesthetic breathing circuits. However, certain features, aspects and advantages of the configurations as described may advantageously be used with other respiratory systems. 
     The term “comprising” as used in this specification means “consisting at least in part of”. When interpreting each statement in this specification that includes the term “comprising”, features other than that or those prefaced by the term may also be present. Related terms such as “comprise” and “comprises” are to be interpreted in the same manner. 
     This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth. 
     The invention consists in the foregoing and also envisages constructions of which the following gives examples only. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Specific embodiments and modifications thereof will become apparent to those skilled in the art from the detailed description herein having reference to the figures that follow, of which: 
         FIG.  1    shows a typical airway of a person, and includes arrows to indicate how a relatively high flow rate of gases supplied to a user may be utilised to effectively push or drive the supplied gases further or deeper into a user&#39;s airway than when the person is under normal or typical self-driven respiratory conditions, or when the patient is apnoeic. 
         FIG.  2    schematically shows a respiratory therapy system incorporating a kit of  FIG.  3  or  4   , with a patient P wearing a patient interface. 
         FIG.  3    shows components of a first configuration kit or apparatus for use in the respiratory therapy system. 
         FIG.  4    shows components of a second configuration kit or apparatus for use in the respiratory therapy system. 
         FIG.  5    shows a side elevation in cross section of an exemplary filter for use in the kit or apparatus. 
         FIGS.  6 A- 6 D  demonstrate the process of assembly of the filter of  FIG.  5   . 
         FIG.  6 E  is a cross-sectional view through  FIG.  6 F .  FIG.  6 F  illustrates an arrangement in which a filter housing has an adapter insert located within a port, and another component is made in connection with the adapter insert. 
         FIG.  6 G  is a side view of an adapter insert, inclusive of sealing members. 
         FIG.  6 H  is the adapter insert of  FIG.  6 G , rotated through 90°. 
         FIG.  6 I  is a cross-sectional view of the adapter insert of  FIG.  6 G . 
         FIG.  63    is a side view of an adapter insert, exclusive of sealing members. 
         FIG.  6 K  is a cross-sectional view of the adapter insert of  FIG.  6 J . 
         FIGS.  6 L  and M are different end perspective views of an adapter insert. 
         FIG.  6 N  is an exploded perspective view of the parts shown mated or engaged (or in connection with each other) of  FIGS.  6 E and  6 F . 
         FIG.  7    is a perspective view of a first exemplary form nasal cannula assembly for use in the kit or apparatus. 
         FIG.  8    is an exploded perspective view of the first form of the nasal cannula assembly of  FIG.  7   , showing two parts making up the nasal cannula, a face mount part and gases flow manifold part attached to tubing supplying gases to the patient. 
         FIG.  9    is a perspective view of a second exemplary form nasal cannula assembly for use in the kit or apparatus, showing tubing providing a gases supply to a gases flow manifold part and face mount part when in connection. 
         FIG.  10    is a perspective view of the second form of the nasal cannula assembly of  FIG.  9    where the gases flow manifold part is disengaged from the face mount part. 
         FIG.  11    is a perspective view of the second form of the nasal cannula assembly of  FIG.  9    where the gases flow manifold part is disengaged from the face mount part, showing the manifold part can be fitted to either side of the face mount part. 
         FIG.  12    is a back perspective view of the second form of the nasal cannula of  FIG.  9   , showing a removable breathable pad on the inner side of the face mount part that abuts the patient&#39;s face. 
         FIG.  13    is a perspective view of a third exemplary form nasal cannula assembly for use in the kit and apparatus, particularly showing a gases flow manifold part that allows for the attachment of removable prongs. 
         FIG.  14    is a perspective view of the third form of the nasal cannula assembly, showing a strap and breathable pad fittable to the manifold part of  FIG.  13   . 
         FIG.  15    is a perspective view of a first form of removable prongs capable of being attached to the manifold part of  FIG.  13   . 
         FIG.  16    is a perspective view of a second form of removable prongs capable of being attached to the manifold part of  FIG.  13   . 
         FIG.  17    is a perspective view of a patient wearing the nasal cannula assembly of  FIG.  9   , showing the use of a neck tie to take some weight of the tubing and a head strap assisting in the maintaining of the assembly to the patient&#39;s face. 
         FIG.  18    is a front view of a patient wearing a nasal cannula assembly where the assembly is held to the patient&#39;s face with the assistance of ear loops. 
         FIG.  19    is a side view of the patient and nasal cannula assembly of  FIG.  18   . 
         FIG.  20    is a perspective view of an exemplary tracheostomy fitting that could be used in the kit and apparatus instead of a nasal cannula assembly. 
         FIG.  21    is a front view of a patient with the tracheostomy fitting of  FIG.  20    attached to a breathing supply where a neck tie or lanyard is used to support the conduit supplying gases to the patient 
         FIG.  22 A  is a schematic representation of a connector or component comprising a filter element. 
         FIG.  22 B  is a schematic representation of a connector or component comprising an alternative filter element. 
         FIG.  22 C  is a schematic representation of a connector or component comprising another alternative filter element. 
         FIG.  22 D  is a schematic representation of a connector or component comprising yet another alternative filter element. 
         FIG.  22 E  is a schematic representation of yet another alternative filter element. 
         FIGS.  23 A and  23 B  are schematic representations of a connector or component comprising a one way valve and a filter element integrated with the one way valve.  FIG.  23 A  shows the one way valve in a closed configuration and  FIG.  23 B  shows the one way valve in an open configuration. 
         FIG.  24 A  illustrates a disinfection capsule or reservoir adapted to be inserted into an end of a breathing conduit. 
         FIG.  24 B  is a schematic cross section representation of the disinfection capsule of  FIG.  24 A  fitted into an end of a conduit. 
         FIG.  25 A  illustrates an end of a breathing circuit conduit and a schematic representation of a sheet of radiation delivered at the end of the conduit to prevent contamination. 
         FIGS.  26 A and  26 B  illustrate a cap provided to a breathing circuit to prevent contamination entering the breathing circuit. 
         FIG.  27 A  illustrates a one way valve in a portion of a breathing circuit or patient interface, and shows the valve in a closed position and also in an open position. 
         FIG.  27 B  illustrates an alternative one way valve in a portion of a breathing circuit or patient interface, and shows the valve in a closed position and also in an open position. 
         FIG.  27 C  illustrates an alternative one way valve in a portion of a breathing circuit or patient interface, and shows the valve in a closed position and also in an open position. 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    shows a typical airway of a person, and includes arrows to indicate how a relatively high flow rate of gases supplied to a user may be utilised to effectively push or drive the supplied gases further or deeper into a user&#39;s airway than when the person is under normal or typical self-driven respiratory conditions. The use of high flow rate gas delivery helps to push the gas flow and hence O2 deeper into the patient&#39;s airways. In some situations, the high flow rate of gas delivery may be utilised when the patient is not spontaneously breathing, i.e. when the patient is apnoeic. 
     The apparatuses described herein may be used in respiratory care or therapy systems, whether high or low flow therapy, or whether as a sealed or non-sealed interface, for example humidified PAP delivery or in-hospital respiratory care systems. 
       FIG.  2    illustrates a humidifying respiratory circuit. A patient P is receiving humidified and pressurised gases through a nasal cannula assembly of a patient interface  601  that is operatively connected to a humidified gases transportation pathway or inspiratory conduit  401  via a filter  501 . The inspiratory conduit  401  in turn is connected to a humidifier  200  (including humidifier chamber  251 ) that is supplied with gases from a blower  15  or other appropriate gases supply means via a gases delivery conduit  301 . The gases delivery conduit is a ‘dry’ conduit; that is, it is positioned upstream of the humidifier. Headgear  620  is provided to support and retain the patient interface against the patient&#39;s face. 
     The inspiratory conduit  401  is connected to the outlet  257  of the humidifier chamber  251  which contains a volume of liquid such as water. Humidifier chamber  251  may be formed from a plastics material and may have a highly heat conductive base  259  (for example an aluminium base) which is in direct contact with a heater plate  203  of humidifier  200 . 
     The humidifier  200  is provided with control means or electronic controller  205  which may comprise a microprocessor based controller executing computer software commands stored in associated memory. Gases flowing through the inspiratory conduit  401  are passed to the patient by way of the filter  501  and patient interface  601 . 
     The controller  205  receives input from sources such as user input means or dial  207  through which a user of the device may, for example, set a predetermined required value (pre-set value) of humidity or temperature of the gases supplied to patient P. In response to the user set humidity or temperature value input via dial  207  and other possible inputs such as internal sensors that sense gases flow or temperature, or by parameters calculated in the controller, controller  205  determines when (or to what level) to energise heater plate  203  to heat the water within humidifier chamber  251 . As the volume of water within humidifier chamber  251  is heated, water vapour begins to fill the volume of the chamber above the water&#39;s surface and is passed out of the humidifier chamber  251  outlet port  257  with the flow of gases (for example air) provided from a gases supply means or blower  15  which enters the chamber through gases inlet port  255 . It should be noted that it is possible to obtain the relationship between the humidity of the gases in humidifier chamber  251  and the temperature of the heater plate  203 . Accordingly, it is possible to utilise the heater plate temperature in an algorithm or a look-up table to determine the humidity of the gases. 
     The blower  15  may be provided with a variable speed pump or fan  2  which draws air or other gases through the blower inlet  17 . The speed of variable speed pump or fan  2  may be controlled by a further control means or electronic controller  18  (or alternatively the function of this controller  18  could be carried out by the other controller  205 ) in response to inputs from controller  205  and a user set predetermined required value (pre-set value) of pressure or fan speed or flow rate via dial  19  or other input device. Alternatively, the gases may be provided from a wall supply; i.e. a wall gas port GP in a wall W. 
     A housing  16  of the blower is provided with an outlet port  20 . An inlet port  303  of the gases delivery conduit  301  and the outlet port  20  of the blower are provided with complementary coupling features to connect the outlet port  20  with the inlet port  303 , and to provide a gases flow path therethrough. The complementary coupling features may in part be provided by an adapter insert, such as that adapter insert  900 , which provides for male connection fingers. In this way, the various ports of the item or component to which an adapter insert may be attached or connected can be considered to be an ‘another component’ as is described elsewhere in this specification in relation to what an adapter insert may be attached or connectable to. 
     The male connection fingers can provide for a first part of a complementary coupling. 
     In some configurations, rather than using a blower  15 , gases flow may be obtained from some other source(s) of gas. For example, in some configurations, source(s) of gas may comprise one or more containers of compressed air and/or another gas and one or more valve arrangements adapted to control the rate at which gases leave the one or more containers. As another example, in some configurations, gases may be obtained from an oxygen concentrator. The system may also include a supplementary gases source to provide an air and supplementary gas mixture. For example, the supplementary gas might be O2. In some configurations, the apparatus may be adapted to deliver a high flow therapy. 
     “High flow therapy” as used in this disclosure may refer to delivery of gases to a patient at a flow rate of greater than or equal to about 5 or 10 liters per minute (5 or 10 LPM). 
     In some configurations, ‘high flow therapy’ may refer to the delivery of gases to a patient at a flow rate of between about 5 or 10 LPM and about 150 LPM, or between about 15 LPM and about 95 LPM, or between about 20 LPM and about 90 LPM, or between about 25 LPM and about 85 LPM, or between about 30 LPM and about 80 LPM, or between about 35 LPM and about 75 LPM, or between about 40 LPM and about 70 LPM, or between about 45 LPM and about 65 LPM, or between about 50 LPM and about 60 LPM. For example, according to those various embodiments and configurations described herein, a flow rate of gases supplied or provided to an interface or via a system, such as through a flowpath, may comprise, but is not limited to, flows of at least about 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150 L/min, or more, and useful ranges may be selected between any of these values (for example, about 40 to about 80, about 50 to about 80, about 60 to about 80, about 70 to about 100 L/min, about 70 to 80 L/min). 
     Gases delivered may comprise a percentage of oxygen. In some configurations, the percentage of oxygen in the gases delivered may be between about 20% and about 100%, or between about 30% and about 100%, or between about 40% and about 100%, or between about 50% and about 100%, or between about 60% and about 100%, or between about 70% and about 100%, or between about 80% and about 100%, or between about 90% and about 100%, or about 100%, or 100%. 
     High flow therapy has been found effective in meeting or exceeding the patient&#39;s normal real inspiratory demand, to increase oxygenation of the patient and/or reduce the work of breathing. Additionally, high flow therapy may generate a flushing effect in the nasopharynx such that the anatomical dead space of the upper airways is flushed by the high incoming gas flows. This creates a reservoir of fresh gas available of each and every breath, while minimising re-breathing of carbon dioxide, nitrogen, etc. 
     The humidifier  200  has a humidifier base comprising a housing  201  with the heater  203 , the controller  205  that is coupled to the heater, and the user input device  207  to enable a user to turn on and off the humidifier and to select a desired temperature to be provided by the heater. The user input device  207  may for example be a button, switch, or touch screen display. The heater  203  may comprise one or more heating elements. 
     The humidifier base is configured to receive the humidifier chamber  251 . The humidifier chamber  251  comprises a housing  253  defining an internal liquid reservoir  254 , an upstream gases inlet port  255  in fluid/pneumatic communication with the liquid reservoir, a downstream gases outlet port  257  in fluid/pneumatic communication with the liquid reservoir, and a base  259 . The base  259  is arranged to be positioned on or above the heater  203  to heat liquid in the liquid reservoir. The base may comprise a flange  261  that projects outwardly from an adjacent portion of the housing  253 , to assist with locating the humidifier chamber in position on the humidifier base. 
     The gases inlet port  255 , the liquid reservoir  254 , and the gases outlet port  257  are in fluid/pneumatic communication to provide a gases flow path from the gases inlet port  255 , through or past the liquid reservoir, to the gases outlet port  257  to heat and humidify gases travelling along the gases flow path. 
     The humidifier chamber  251  may be any suitable chamber that holds suitable liquid for use in humidifying gases, such as water for example. The humidifier chamber  251  may be a manual fill chamber, and may be filled through a liquid inlet port  263 . Alternatively, the humidifier chamber  251  may be an automatically filling chamber, and liquid may be fed to the humidifier chamber from a liquid container, bag, or other liquid source. The humidifier chamber may comprise a float valve in the liquid reservoir, the float valve configured to control flow of liquid form the liquid container into the liquid reservoir. 
     A gases delivery conduit  301  is located upstream of the humidifier chamber  251 . The gases delivery conduit  301  is in fluid/pneumatic communication with the humidifier chamber  251  or is configured to be placed in fluid/pneumatic communication with the humidifier chamber upstream of the humidifier chamber; i.e. with the humidifier chamber  251  downstream of the gases conduit  301 . The gases delivery conduit  301  is configured to receive one or more gases from a source of gas and deliver the gas(es) to the gases inlet port  255  of the humidifier chamber. 
     The gases delivery conduit  301  has an upstream gases inlet port  303  at one end of the conduit, and a downstream gases outlet port  305  at the opposite end of the conduit. The gases inlet port  303  and the gases outlet port  305  are in fluid/pneumatic communication to provide a gases flow path from the gases inlet port  303  through the gases delivery conduit to the gases outlet port  305 . The gases outlet port  305  of the gases delivery conduit and the gases inlet port  255  of the humidifier chamber  251  may comprise complementary coupling features, to enable the gases delivery conduit  301  to be coupled to the humidifier to provide fluid/pneumatic communication between the gases delivery conduit  301  and the humidifier chamber  251 . The complementary coupling features of the gases outlet port  305  of the gases delivery conduit  301  and the gases inlet port  255  of the humidifier chamber  251  may be disconnectable from each other to enable the gases delivery conduit  251  to be decoupled from the humidifier chamber  251 . Alternatively, the complementary coupling features may be permanently or semi-permanently coupled. 
     In relation to the complementary coupling features, at least some of those may be provided by an adapter insert, such as adapter insert  900  comprising of male connection fingers  901 . 
     The gases inlet port  303  of the gases delivery conduit may be provided with coupling feature(s) to enable the gases delivery conduit to be coupled to the source of gas. 
     An inspiratory conduit  401  extends from the humidifier chamber  251  to link the humidifier to a patient interface  601  via an in-line filter  501 . The inspiratory conduit  401  may comprise a conduit heater  403  adapted to heat gases passing through the conduit  401 . The heater  403  will help minimise or prevent the formation of condensation in the inspiratory conduit, which could otherwise occur due to a temperature differential between the interior of the conduit wall and exterior of the conduit wall. In other configurations the conduit heater  403  may not be present. The inspiratory conduit  401  comprises an upstream gases inlet port  409  at one end of the conduit and a downstream gases outlet port  405  at the opposite end of the conduit, with the conduit defining a gases flow path from the gases inlet port  409  to the gases outlet port  405 . 
     The humidifier chamber  251  is in fluid/pneumatic communication with the inspiratory conduit  401  upstream of the inspiratory conduit  401  or is configured to be placed in fluid/pneumatic communication with the inspiratory conduit  401  upstream of the inspiratory conduit; i.e. with the inspiratory conduit positioned downstream of the humidifier chamber  251 . The gases outlet port  257  of the humidifier chamber  251  and the gases inlet port  409  of the inspiratory conduit  401  may comprise complementary coupling features, to enable the inspiratory conduit to be coupled to the humidifier to provide fluid/pneumatic communication between the humidifier chamber  251  and the inspiratory conduit  401 . The complementary coupling features of the gases outlet port  257  of the humidifier chamber  251  and the gases inlet port  409  of the inspiratory conduit  401  may be disconnectable from each other to enable the inspiratory conduit  401  to be decoupled from the humidifier chamber  251 . Alternatively, the complementary coupling features may be permanently or semi-permanently coupled. 
     The inspiratory conduit  401  will typically have a longer length than the gases delivery conduit  301 . 
     The filter  501  comprises a generally cylindrical filter housing  503  with an enlarged central body portion. A leading edge of the enlarged central body portion comprises a tapering wall that terminates at an upstream gases inlet port  505 , and a trailing edge of the enlarged central body portion terminates at a downstream gases outlet port  507 . The gases inlet port  505  and gases outlet port  507  are in fluid/pneumatic communication via the central body portion. The filter may be a high-efficiency particulate arrestance (HEPA) filter. The enlarged central portion of the filter housing contains suitable filtration material. For example, the filtration material may comprise pleated paper, nano-fibers, or any other suitable filtration material, including sock filters, stacked disc filters, spiral filters, block(s) of filter material, a disc or discs of filter material with streams of filter material to free flow from or off the disc in fluid flow. The filter captures and prevents downstream passage therethrough of particulates, bacteria and/or other infectious material from the inspiratory conduit to the patient, and also captures and prevents upstream passage therethrough of bacteria and/or other infectious material from the patient to the inspiratory conduit. 
     An exemplary filter is described herein with reference to  FIGS.  5  to  6 D . Alternatively, the filter could be any other suitable type. 
     The inspiratory conduit  401  is in fluid/pneumatic communication with the filter  501  upstream of the filter or is configured to be placed in fluid/pneumatic communication with the filter upstream of the filter; i.e. with the filter located downstream of the inspiratory conduit. The gases inlet port  505  of the filter  501  and the gases outlet port  405  of the inspiratory conduit  401  comprise complementary coupling features, to enable the inspiratory conduit to be coupled to the filter to provide fluid/pneumatic communication between the inspiratory conduit and the filter. The complementary coupling features of the gases inlet port  505  of the filter and the gases outlet port  405  of the inspiratory conduit are disconnectable from each other to enable the inspiratory conduit  401  to be decoupled from the filter  501 . 
     In one configuration, the complementary coupling features between the gases outlet port  405  of the inspiratory conduit  401  and the gases inlet port  505  of the filter comprise a 22 mm medical connection or 22 mm medical taper connection.  FIG.  3    shows an electrical connector  407  on the gases inlet port  409  of the inspiratory conduit. The electrical connector may provide for a power connection to a heater wire of the inspiratory conduit, or therethrough to any associated components with inspiratory conduit or other parts of the kit or assembly. The electrical connector may also all provide connection to signal, communication or sensor wires. 
     The filter  501  is in fluid/pneumatic communication with the patient interface  601  upstream of the patient interface or is configured to be placed in fluid/pneumatic communication with the patient interface  601  upstream of the patient interface  601 ; i.e. with the patient interface located downstream of the filter. In one configuration, the filter  501  is coupled to the patient interface  601  or is configured to be coupled to the patient interface  601 . 
     The patient interface  601  comprises a patient interface gases conduit  603  with an upstream gases inlet port  605  at one end of the conduit. The opposite downstream end of the patient interface gases conduit  603  is in fluid/pneumatic communication with a patient cannula  30 / 607  to deliver gases from the patient interface gases conduit  603  to a patient P. 
     In one configuration, the gases outlet port  507  of the filter  501  and the gases inlet port  605  of the patient interface gases conduit comprise complementary coupling features to enable the filter  501  to be coupled to the patient interface  601  to provide fluid/pneumatic communication between the filter and the patient interface gases conduit, with the filter in-line with a gases flow path through the patient interface gases conduit. The complementary coupling features may be disconnectable from each other to enable the filter to be decoupled from the patient interface gases tube of the patient interface. Alternatively, the complementary coupling features may be permanently or semi-permanently coupled. 
     In one configuration, the complementary coupling features between the gases outlet port  507  of the filter  501  and the gases inlet port  605  of the patient interface  601  comprise a 22 mm medical taper connection. 
     In an alternative configuration, the patient interface  601  comprises a patient interface gases conduit  603 , and the filter  501  is integrally formed with the patient interface gases conduit to provide fluid/pneumatic communication between the filter  501  and the patient interface gases conduit  603 , with the filter in-line with a gases flow path through the patient interface gases conduit. That is, the filter and patient interface may be an integrated unit. 
     In a further alternative, the complementary coupling features may at least in part be provided by an adapter insert, for example the male connection fingers  901  of an adapter insert  900 . Such male connection fingers  901  can provide for a first of a complementary connection features, while the other of the complementary connection features can be provided by the other component, for example an end of component  805  (all for example as shown in  FIG.  6 E ). In this manner, a filter (such as filter  501 ) can be suitably adapted to be provided with complementary connection features allowing for the coupling and decoupling of such a filter from a respiratory circuit as desired. 
     In one configuration, a plurality of filters, such as each being provided in an in-line configuration, for example as a ‘common filter’ as previously described herein, can be used with the nasal cannula or nasal mask or other patient interfaces. The plurality of filters that are in-line to form a common filter may receive a flow of gas from an inspiratory conduit at the inlet port of the common filter. The outlet port of the common filter may be in pneumatic connection with a patient interface for delivering gas filtered by the common filter to a patient. 
     The patient interface  601  is shown to be a nasal cannula, although it should be understood that in some configurations, other patient interfaces may be suitable. For example, in some configurations, the patient interface may comprise a sealing or non-sealing interface, and may comprise a nasal mask, an oral mask, an oro-nasal mask, a full face mask, a nasal pillows mask, a nasal cannula, an endotracheal tube, a tracheostomy tube, a combination of the above or some other gas conveying system. In an embodiment, the patient interface  601  comprises a non-sealing interface such as a nasal cannula, which allows gases to be exchanged with the environment. For example, the non-sealing cannula allows carbon dioxide to be removed and/or cleared from the patient&#39;s airways while the patient receives flow therapy from the system. Further, in an embodiment, the patient interface is in the form of a nasal interface, such that the system does not interfere with other oral airway equipment and/or devices, for example, a tracheal tube in an intubation procedure. Accordingly, the patient may continue to receive flow therapy throughout the intubation procedure. 
     The patient interface gases conduit  603  forms a first gas lumen defined by a tubular wall. The first gas lumen is adapted to receive gases from the respiratory therapy system, via the inspiratory conduit  401  and filter  501  shown in  FIG.  2   , and channel the gases to the patient P. 
     The illustrated first gas lumen is defined at least in part by a wall within which gases can be channelled. 
     The first gas lumen may optionally comprise a reinforcement element adapted to strengthen and/or add rigidity to the first gas lumen to prevent deformation or collapse of the first gas lumen arising due to the application of forces against the first gas lumen. The reinforcement element may include a number of structures, including but not limited to plastic or metallic reinforcing beads that lie in or on the wall of the first gas lumen. Alternatively, the lumen may, in some configurations, comprise weakened sections, or sections which are unable to self-maintain their flow path or a fluid flow passage, to allow for a mask to seal over the patient interface, such as a nasal cannula or nasal mask, and to reduce or prevent the flow of gases to the patient interface. 
     The first gas lumen  603  is in fluid/pneumatic communication with a flow manifold  609 . The flow manifold  609  receives gases from the first gas lumen  603  and passes them to one or more nasal delivery elements  611  (e.g. the nasal prongs of a nasal cannula). The one or more nasal delivery elements  611  extend outwardly from the flow manifold  609 . The one or more nasal delivery elements  611  are adapted to be non-sealingly positioned in one or more nares of the patient P. 
     As shown, in one example, the patient interface  601  can comprise two nasal delivery elements  611  adapted to be positioned one in each of the patient&#39;s nares. Each nasal delivery element  611  may be shaped or angled such that it extends inwardly towards a septum of the patient&#39;s nose. 
     Additionally, each nasal delivery element may be shaped or angled such that a tip of each nasal delivery element points, in use, towards a back of the head of the patient P. In the embodiment shown in  FIGS.  2  and  3   , the flow manifold  609  receives flow from one lateral side of the flow manifold  609  (e.g. with respect to an imaginary vertical plane bisecting the face of the patient P) and channels flow to each of the nasal delivery elements  611 . In other configurations, the patient interface  601  may comprise greater (for example, three or four) or fewer (for example, one) nasal delivery element  611 . 
     In other configurations, each nasal delivery elements  611  can have different properties. For example, one of a pair of nasal delivery elements  611  can be relatively long and the other nasal delivery element  611  can be relatively short. In some configurations, the flow manifold  609  may be configured to receive flow from two lateral sides of the flow manifold  609  (e.g. from a ‘left’ and ‘right’ of the flow manifold  609  when instead of just the ‘left’ of the flow manifold  609  as seen in  FIG.  2   ). In some such configurations, multiple gas lumens may be used to provide for pneumatic communication between the flow manifold  609  and the respiratory therapy system. In some configurations, the flow manifold  609  may be configured to receive flow from a non-lateral side of the flow manifold  609  (e.g. from a ‘bottom’ or ‘top’ of the flow manifold  609 ). 
     In other configurations, as noted, the manifold may be a separately attachable component to be attached to the body of the interface, such as a nasal cannula or nasal mask. Such a manifold may be an entirely separate component able to be removed from attachment to the interface, or it may be de-attached or disconnected from an operational position to allow for a re-orientation of the manifold (and associated supply conduit) relative to the interface. For example, the manifold may be of a push-fit type arrangement to be push-fitted into a connection with the interface body, or may be of a swivel-type connection with the body of the interface allowing for a re-orientation of the manifold. A re-orientation allows for the supply conduit to be positioned to a left or a right side of the interface (and therefore changed from one side to another of the patient). This may allow for an improved convenience or arrangement of components in a system delivering gas to the patient. For example, if those assisting in a medical procedure need access to the patient from one particular side, then the manifold can be re-oriented and the supply tube re-positioned so as to extend from a different side of the patient. Such an arrangement allows for a relatively unobtrusive application of a patient interface and its associated components away from medical specialists. 
     The patient interface when in the form of a nasal cannula may utilise a headgear in the form of a strap that can be bifurcated (i.e. a line of weakness or other split arrangement can be configured) to allow for the headgear or a strap thereof to be reconfigured from a single strap arrangement into a bifurcated strap arrangement. 
     The patient interface when in the form of a nasal cannula may utilise a pair of side arms extending from the main body (to which the manifold is to be put into connection with). The side arms may comprise of features allowing for the retention or securement or positioning of a gas supply tube to the side arm (to prevent the gas supply tube from uncontrollably moving about). 
     The patient interface  601  may further comprise mounts and/or supports, e.g., cheek supports, for attaching and/or supporting the gas lumen  603  and/or cannula  30 / 607  on the patient&#39;s face. For example, a releasable connection system may be utilised to position or locate the interface upon the patent&#39;s face, yet allow for a relatively rapid removal or re-positioning of the interface if necessary. 
     The filter may be coupled to an interface tube, such as a patient interface gases conduit or gas lumen, that is coupled to the manifold. The patient interface gases conduit or gas lumen may be a short section of tube or conduit. For example, the patient interface gases conduit or gas lumen may be about 20 cm to about 50 cm long, or about 25 cm to about 40 cm long, or about 30 cm to about 35 cm long, or may be about 32 cm long. 
       FIG.  3    additionally shows a component  410  located on or about a conduit, such as an inspiratory conduit  401 . The component  410  is adapted to engage with the conduit, such as the inspiratory conduit  401 , and is provided with jaws  413  extending from a body  411  of the component  410 , the jaws  411  being adapted to grip an item and thereby support the conduit, such as inspiratory component  401 , in use. 
     The jaws  411  may be a pair of opposing jaws for gripping of an item, such as a sheet or article of clothing or other item or article (e.g. a medical stand or component attached thereto) (not shown). The jaws  411  of the component  410  may be co-acting upon each other in a closed position. 
     The body of the component may substantially surround a perimeter of the conduit or tube upon which it is located. 
     The ability to locate a medical tube, such as an inspiratory conduit or tube, relative to a user has certain advantages. Being able to help support the weight of the medical tubing connected to equipment associated with the user has a number of advantages including but not limited to, for example, reducing the weight transferred to a user or equipment associated with the user, which may in turn impact on the efficiency of a treatment being provided to a user, or the overall comfort experienced by a user when using such equipment. 
     Further, as a user moves or re-positions their body relative to the medical tubing or associated equipment, strain may be transferred to the tubing or to the user via the associated equipment. A relatively quick and effective re-positioning or re-locating of the tubing to provide support again would be useful. 
     Such a component  410  can be utilised to position or locate, for example, inspiratory medical tubing, or other tubing associated with such medical circuits. 
     Accordingly, the component  410  is provided for use with a tube or conduit, such as an inspiratory conduit  401 . The component  410  generally comprises a body  411  engageable with the external surface of a conduit or tube (e.g. such as the external surface of a corrugated tube—as for example shown in  FIG.  3   ). The component  410  includes a pair of jaws  413  that extend from the body  411 . The jaws  413  can be used for attaching to or for gripping of an item (not shown). 
     As shown in  FIG.  3   , the body  411  comprises a shoulder portion  412  associated with each jaw of the pair of jaws  413 , the shoulder portion  412  providing a surface for actuation, by a user. The shoulder portion  412  is an enlarged region of the body  413 . The shoulder portions  412  can be sized for actuation by fingers of a user, or are finger tabs. 
     It will be appreciated, the body  411  is configured to be substantially annular about the exterior surface of the, or each, respective tube or conduit, such as inspiratory conduit  401 , upon which it is to be provided in association. 
     The component  410  may be a tube clip capable of engaging with an exterior surface or surfaces of a conduit or tube, such as the inspiratory conduit  401 , where the tube clip additionally comprises a pair of jaws  413  adapted for gripping of an item, such that when the jaws  413  of the tube clip grip an item, the conduit or tube may be supported. The component  410  may for example be that as described by PCT/NZ2012/000169 (published as WO2013/073970) the entirety of the contents of which is incorporated herein by reference. 
     Kit and Use 
       FIG.  3    shows the form in which the components of the described apparatus will be provided for use with a patient. The described components will be provided as a kit in a package that comprises a sealed container or bag, which is represented by the broken line in  FIG.  3   . The package may, for example, be a clam shell package. The container or bag will contain the humidifier chamber  251 , the gases delivery conduit  301 , the inspiratory conduit  401 , the filter  501 , and the patient interface  601 . Optionally, a tube clip (such as component  410 ) can also be provided in such a package. The tube clip can be provided for attachment or already attached to the inspiratory conduit  401  (and for example may be positioned or located near the patient end of such a conduit) for securing the conduit to an item (such as bedding etc.) to help reduce the load of the circuit on the patient&#39;s face, or support the circuit, and to thereby reduce the risk of dislodging the interface from the patient. 
     Optionally, an adapter (such as adapter insert  900 ) can also be provided in such a package. The adapter (such as adapter insert  900 ) can be used to facilitate connection between components of the system. Optionally, inlets and/or outlets of conduits in the system may comprise engagement features (for example those of another connector  805 ) which act to couple with the features of the adapter. 
     One or some of the components may be provided separately in the package; that is, they will not be coupled together. In one configuration, the filter  501 , the humidifier chamber  251 , the inspiratory conduit  401 , and the gases delivery conduit  301  are provided separately in the package. The patient interface  601  and filter  501  may be provided separately in the package (i.e. not coupled or integrated). Alternatively, the patient interface and filter may be coupled in the package, or the filter may be integrally formed with the patient interface gases conduit of the patient interface. 
     Each of the various components may be provided in their appropriately coupled or connected arrangement with each other, or may be provided in a decoupled or disconnected arrangement or variations of these. For example, it may be appropriate in the package to provide for the patient interface and filter to be provided in an already coupled arrangement, such as via the gases delivery conduit  301 , yet these components may not be already provided as being coupled to the humidifier chamber  251  or an inspiratory conduit  401 . In further arrangements, an inspiratory conduit  401  component may be provided in a coupled arrangement with a gas inlet of the humidifier chamber  251 . Further, those components that are intended to be changed between patients, such as a patient interface  601 , gases delivery conduit  301  and filter  501  may be provided in a separate part of the package; whilst those parts which are to remain in the circuit despite multiple patients receiving therapy or a treatment (e.g. those parts upstream of the filter), such as the humidifier chamber  251  and inspiratory conduit  401 , may be provided in another separate part of the package. Discrete parts or separations in the package may assist with maintaining cleanliness of the different components until they are required for use. 
     Method of Assembling Breathing Circuit Using the Apparatus, and Use of the Apparatus 
     The apparatus described above enables the gases delivery conduit  301 , inspiratory conduit  401 , and humidifier chamber  251  to be re-used with multiple patients. The filter  501  will prevent contamination of the inspiratory conduit  401  by each patient. Each patient will have their own filter  501  and patient interface  601 . 
     The package shown in  FIG.  3    will be provided for a first patient in a specified time period. The time period is one in which it is acceptable in a medical setting to re-use the inspiratory conduit  401 , humidifier chamber  251 , and gases delivery conduit  301 . 
     A method of assembling a breathing circuit using the package of  FIG.  3    would comprise, positioning the gases delivery conduit  301  upstream of the humidifier chamber  251  and downstream of a source of gas, and coupling the gases delivery conduit  301  to the source of gas (for example, by connecting the gases delivery conduit to a wall gases source such as gas port GP via a flow controller such as a flow control valve or a control knob) and to the humidifier chamber  251 ; positioning the humidifier chamber  251  on the humidifier base  201 ; positioning the inspiratory conduit  401  downstream of the humidifier chamber  251 , and coupling the inspiratory conduit  401  to the humidifier chamber  251 ; positioning the filter  501  and patient interface  601  downstream of the inspiratory conduit  401 , and coupling the filter  501  to the inspiratory conduit  401  and, if not already coupled, coupling the filter  501  to the patient interface  601 ; positioning the patient interface  601  on the patient; receiving gas at the humidifier  251  from the source of gas, humidifying the gas, receiving humidified gas at the filter  501  from the humidifier  251 , and delivering the humidified gas from the filter to the patient interface  601 . It will be appreciated that the steps of the method can be carried out in any suitable order or concurrently. 
     The assembled apparatus may be used to deliver gases to a patient during pre-oxygenation, when the patient is being anaesthetized and/or when the patient has been anaesthetized (i.e. during the apnoeic window). For example, the apparatus may be used to deliver heated, humidified, high flow gas at between 5 l/min and 150 l/min, and advantageously at least at about 70 l/min, but may also be at least about 50 l/min, when a patient has been anaesthetized. When a patient has been anaesthetized, their respiratory drive is compromised and they are not breathing spontaneously. The high flow maintains the patient&#39;s oxygen levels at a safe level. This provides a useful alternative to a mask and bag that would typically be used to artificially ventilate a patient. 
     The method may additionally or alternatively be used when the patient is being pre-oxygenated prior to being anaesthetized. At that time, the patient is breathing spontaneously. Pre-oxygenation is carried out to increase oxygen concentration in the patient&#39;s lungs. 
     In both instances the temperature of the gases delivered to the patient may advantageously be about 37° C. and the humidity may be about 44 mg/l H 2 O. 
     Connecting Same Kit to Subsequent Apparatus 
     Once the medical procedure on the first patient has been completed, the filter  501 , and thereby the patient interface  601 , will be decoupled from the inspiratory tube  401 . The filter  501  and patient interface  601  can then be discarded. Alternatively, if it is expected or apparent that the patient will require further respiratory support, the patient interface  601  could remain in place on the patient, and the filter  501  that is coupled to that patient interface  601  could then be coupled, either directly or indirectly, to another source of gas. Alternatively, the filter could be removed if not being used or if no further connection with reusable components is required. For example, the other source of gas may be provided elsewhere in the medical facility, such as in a recovery room following a surgical procedure. 
     Subsequently Connecting Another Kit to Same Humidifier/Inspiratory Conduit 
     After the first filter  501  has been decoupled from the inspiratory conduit  401 , a further apparatus comprising a new filter  501  and new patient interface  601  can be coupled to the inspiratory conduit, to enable the gases delivery conduit  301 , humidifier chamber  251 , and inspiratory conduit  401  to be used on a subsequent patient. In particular, a user will position the new filter  501  downstream of the inspiratory conduit  401 , and will couple the filter  501  to the inspiratory conduit  401 . If not already coupled, the user will couple the filter to the patient interface. The method will then involve positioning the new patient interface  601  on the patient; receiving gas at the humidifier  251  from the source of gas, humidifying the gas, receiving humidified gas at the filter  501  from the humidifier  251 , and delivering the humidified gas from the filter to the patient interface  601 . It will be appreciated that the steps of the method can be carried out in any suitable order or concurrently. 
     A similar process of decoupling the used filter  501  and patient interface  601  from the inspiratory conduit  401 , and then coupling a new filter  501  and thereby a new patient interface  601  to the inspiratory conduit  401  can be repeated for subsequent patients. 
     At the end of a specified time period (for example, one day), the humidifier chamber  251 , gases delivery conduit  301 , and inspiratory conduit  401  can all be decoupled and discarded, and a new package as shown in  FIG.  3    can be provided and used for the next time period. 
     Because the gases delivery conduit  301 , humidifier chamber  251 , and inspiratory conduit  401  can all be used multiple times on multiple patients (due to the presence and location of the filter  501 ), most new patients will only require a new filter  501  and new patient interface  601 . Those two components will be provided as a kit in a package that comprises a sealed container or bag. The package may, for example, be a clam shell package. The container or bag may be airtight, and its contents may be sterile. The container or bag will contain the filter  501  and the patient interface  601 . Such a package is shown in  FIG.  4   . 
     The patient interface  601  and filter  501  may be provided separately in the package of  FIG.  4   . Alternatively, the patient interface  601  and filter  501  may be coupled in the package. Alternatively, the filter may be integrally formed with the patient interface gases tube of the patient interface. 
     The use of the patent interface  601  and filter of the package of  FIG.  4    will be as described above. 
     The patient interface  601  and filter  501  will be used with a single patient or user, but may be used to deliver gases from one or more apparatuses; for example, for one patient prior to and/or during an anaesthetic procedure and/or during post-operative recovery. 
     Another kit may comprise a gases delivery conduit  301 , an inspiratory conduit  401 , and a humidifier chamber  251 , but no filter  501  or patient interface  604 . Again, this kit may be provided in a package such as the type described above, and the components may be coupled together or provided separately. 
     The different types of kits may be provided together or separately. For example, a single package may be provided with two or more of the kits of the same or different types therein. 
     Exemplary Filter 
       FIGS.  5  to  6 D  show an exemplary filter  501  that can be used in the described apparatus. Referring to  FIG.  5    the filter has a filter housing F 1  formed from a first housing part F 2  and a second housing part F 3 . The first and second housing parts F 2 , F 3  are joined at their respective peripheries F 4 , F 5 . The peripheries F 4 , F 5  of said first and second parts F 2 , F 3  clamp therebetween the peripheries F 6  of a web F 7  of filter material. The first and second housing parts F 2 , F 3  each include one of an inlet port F 8  and outlet port F 9 . The inlet and outlet ports are essentially indistinguishable and interchangeable. An insulating outer wall F 10  is provided in the form of a cover which covers the main filter media enclosing body of the filter housing F 1 . 
     The filter housing F 1  and the surrounding outer wall F 10  form therebetween a pair of closed air spaces F 11 , F 12 . These closed air spaces F 11 , F 12  insulate the filter housing F 1  from the ambient conditions outside the surrounding outer wall F 10 . The surrounding outer wall F 10  is formed by a pair of cover sections F 13 , F 14  which at their periphery F 15 , F 16  have a “snap fit” connection with one another. Each cover section F 13 , F 14  has a respective collar F 17 , F 18  which fits over the inlet port F 8  or the outlet port F 9  respectively. Each collar F 17 , F 18  has an extension F 19 , F 20  thereof extending towards the web F 7  of the filter media to abut against a face F 21 , F 22  of the respective housing parts F 2 , F 3  extending outwardly from the ports F 8 , F 9  in a direction towards the web F 7  of the filter media. 
     In viewing  FIG.  5    it will be appreciated that in the form shown the filter is rotationally symmetric, so the cross section on any longitudinal plane will look like that in  FIG.  5   . It would of course be possible to construct the filter to have a more rectangular shape, e.g. of the web F 7  of filter media and the associated peripheries F 4 , F 5  of the housing parts F 2 , F 3 , with the wall F 21 , F 22  merging between the rectangular shapes of the peripheries F 4 , F 5  and the circular peripheries of the inlet and outlet ports F 8 , F 9 . 
     In some applications it may be preferred that the filter have more than one port on one or more of the sides of the filter media, for example, two ports on what is a gas supply side of the filter media and a single port on what is a patient side of the filter media. In such case the two ports may for example be side by side or alternatively be coaxial ports for connection to a coaxial tube or splitting connector. In a coaxial arrangement the configuration of the filter housing and the insulating cover may be simply that as shown in  FIG.  5   . In a side by side configuration the respective filter housing part will have a pair of ports and the respective cover section a pair of apertures or openings therethrough to fit closely over the pair of ports. 
     The major components of the filter, excluding the filter media, may be formed from a suitable plastics material, and in particular one approved for medical uses. For example these, the first and second housing parts F 2 , F 3  and the cover sections F 13 , F 14 , may be injection moulded from a medical grade polypropylene material. The filter media may be varied according to the intended application to include, for example antimicrobial properties or simply to be a particle filter. In this latter role the filter material may, for example, be a non-woven felt of electrostatically charged polypropylene fibres, such as that marketed under the trade mark ELECTROSTAT by All Felt Incorporated. A further alternative example of an appropriate filter media may, be a pleated sheet for example made of glass microfiber, or paper, or any other filter media types disclosed herein. 
     Further examples of filter media types comprise of: ceramics, fabricated metals (e.g. woven wire cloth), porous plastics (such as, but not limited to, plastic powders moulded into porous rigid shapes), non-woven media (e.g. dry-formed, wet-laid or membrane). 
     While further examples of filter media materials may comprise of: Cellulose, cotton, wood pulp, glass, fibreglass, glass micro fibre, or composites; polymers, such as polytetrafluoroethylene PTFE, polycarbonate (PC), acrylics including modacrylics, rayon, fluoropolymers, thermoplastic polyurethane (TPU), polyethylene (PE), polyamides, polyester, polypropylene (PP), nylon, metals, such as galvanised steel, stainless steel, aluminium, copper. 
     Composites may consist of polyamides, polyethersulfone, polysulfone, ceramic, carbon or any of the other polymers listed above, such as polytetrafluoroethylene PTFE, polycarbonate (PC), acrylics, rayon, fluoropolymers, thermoplastic polyurethane (TPU), polyethylene (PE), polyamides, polyester, polypropylene (PP), nylon. The composite may be a composite because it is of a multi-layer construction. Separate layers may have different functions, for example support or strength layers, different filtration efficiencies or pore sizes, for the absorption of gases, to contain particles and/or contaminants in the inner or different layers of a composite filter. 
     It will also be appreciated the filter media may be or comprise of electrostatic, hydrophilic or hydrophobic characteristics or properties. 
     Connection between the first and second housing parts F 2 , F 3  may be performed by a permanent bonding process to ensure a suitable seal between the two parts. To that purpose the first and second parts F 2 , F 3  have overlapping flanges F 24 , F 23  respectively and these flanges provide surfaces which may be joined by a suitable adhesive or by ultrasonic welding in a known fashion. To grip the periphery F 6  of the web F 7  of filter media between the peripheries F 4 , F 5  of the first and second housing parts F 2 , F 3  a suitable ridge or ridges F 25  may be provided on one (in this case the second housing part F 3 ) of the housing parts F 2 , F 3 . 
     In use the filter may be connected between the inspiratory conduit  401  and the patient interface  601  between two lengths of breathing circuit, as discussed above. The patient interface tube  603  may, for example, be a breathable tube to prevent or remove condensation and to enable the delivery of gases to the patient at approximately 37° C. With the enclosed space F 26  within the filter  501  being substantially insulated from the ambient conditions outside the outer wall F 10 , condensation forming within the filter on the filter walls will be substantially reduced. In one optional configuration, one or more apertures (not shown) may be provided at a location F 50  in the walls F 21  and/or F 22  of the housing parts F 2 , F 3  adjacent the periphery flanges F 4 , F 5  thereof such that if sufficient such holes are provided any liquid gathering in the spaces F 26  will flow through the apertures and into the air pockets F 11 , F 12 . 
     The insulated filter  501  is of a simple construction. This construction is demonstrated with respect to  FIGS.  6 A to  6 D . The filter involves five simple components being the first and second housing parts F 2 , F 3 , the web F 7  of the filter media and the cover sections F 13 , F 14  forming the outer wall. The first step of assembly is depicted in the cross sectional side elevation of  FIG.  6 A . The housing parts F 2 , F 3  are brought together in the manner indicated by arrows F 26 , F 27  to clamp the peripheries F 6  of the web F 7  of the filter media between the outwardly extending peripheral flanges F 4 , F 5  of the housing parts F 2 , F 3 . Annular projecting ribs F 25  on the forwardly facing surface of the peripheral flange F 5  of housing part F 3  grips the periphery F 6  of the web F 7  of filter material and squeezing same against the periphery flange F 4  of housing part F 2 . The assembled filter housing is thus shown in the side elevation of  FIG.  6 B . In the condition thus shown the periphery flange F 28  of the housing, formed by the periphery flanges F 4 , F 5 , is subject to ultrasonic welding to firmly and sealingly bond together the housing parts F 2 , F 3 . 
     Referring then to  FIG.  6 C , a first cover section F 13  is introduced having a collar F 19  thereof passing over or around the inlet port F 8  of the filter housing F 1 . A second cover section F 14  is introduced to have collar F 20  thereof pass over and around outlet port F 9 . The first and second cover sections F 13 , F 14  are brought together in the direction as indicated by arrows F 29 , F 30  such that the forwardly facing peripheral flanges F 15 , F 16  overlap and the complementary engagement surfaces formed thereon inter-engage to connect the cover sections F 13 , F 14 . 
     The completely assembled filter including insulating cover is depicted in the side elevation of  FIG.  6 D . 
     According to the description herein, and when provided either in combination with those embodiments described herein, or when provided independently of those, there is disclosed a further filter arrangement  701  for use in a respiratory support system for delivering gas to a user or patient. Such a filter arrangement  701  as shown in  FIGS.  6 E,  6 F and  6 N  is of a similar configuration to the filter  501  which is described herein. As such, reference to the details of the filter  501  may be relied upon in relation to being additional details of the filter arrangement  701 . 
     Such a filter arrangement  701  comprises a filter housing  703 . The filter housing  703  has a gases inlet port  707  and a gases outlet port  705 . At least one (or both) of the inlet and/or outlet ports  707 ,  705  is/are adapted for connection with another component  805  (such as a connector provided at a terminal end of a conduit) via one or more (more particularly there may be a pair) of male connection fingers  901 . The male connection fingers  901  extend externally from one or both ports. 
     For example, the male connection fingers  901  can be configured to extend from the gases outlet port  705 , or the gases inlet port  707 , or from both ports  705 ,  707  of the filter arrangement  701 . 
     As is more particularly shown by  FIGS.  6 E- 6 N , one or each of the gases inlet or outlet ports  707 ,  705  can include an adapter insert  900 . 
     An adapter insert  900  is configured to facilitate a connection with another component, such as a connector located at the terminal end of a conduit, for example to a gases inlet port  605  of another component as illustrated in  FIG.  4   . 
     The adapter insert  900  comprises one or more (in particular a pair of) male connection fingers  901 . The male connection fingers  901  extend from a first end  902  of the adapter insert. 
     The male connection fingers  901  can optionally comprise of indentations or recesses (or even whole windows)  915 . These recesses  915  can be shaped for suitable engagement of a projection or protrusion  820  located or provided on another component  805  which is to receive the male connection fingers  915 . 
     The adapter insert  901  comprises one or more retention members  903  provided at a second end  904  of the adapter insert  900 . Each retention member  903  is configured to be substantially engageable with an interior surface portion  709  of the filter housing  703 . 
     Each retention member  903  is configured for an engagement with the interior surface  709  of the filter housing  703  to retain the adapter insert  900  within a port (e.g. either of both of those ports indicated as items  707  or  705 ) into which the adapter  900  is to be inserted. 
     In use, each retention member  903  when engaged with the internal surface  709  of the filter housing  703  acts to resist axial displacement (such as detachment) of adapter insert  900  from being moved in a direction toward an exterior end  711  of a port into which the adapter insert  900  is located. 
     Each retention member  903  can be configured to include at least a hook or other surface projection to more positively engage or latch with the internal surface  709  of a filter housing  703 . 
     In various embodiments, there may be one or more retention members  903 , or a plurality of retention members  903 , or there be two retention members  903  provided, or in yet other embodiments there can be four retention members  903 . 
     A single retention member  903  may be provided. However, there may be more than one retention member  903  utilised, and in such instances, such retention members  903  can be arranged symmetrically around the second end  904  as a series or sequence of formations or may together form an array about the second end  904 , which in turn provide for an array of retainers engageable with an interior surface  709  of the filter housing  701 . 
     Extending between the first end  902  from which the male connection fingers  901  extend, and the second end  904  from which the one or more retention members  903  extend, is a shank portion  905 . The shank portion  905  connects the first end  902  with the second end  904 . 
     The shank portion  905  includes a lumen or gas flow path  912  for the passage of gases therethrough between each of the first and second ends  902 ,  904 . In particular embodiments, the gas may flow in a direction from the second end  904  to the first end  902 . 
     The lumen or gas flow path  912  can be configured and/or be internally shaped so as to transition from a substantially wider bore (or larger internal diameter) at the second end  904  of the adapter insert  900  to a substantially narrower bore (or a smaller internal diameter) at the first end  902 . In particular embodiments, the lumen or gas flow path  912  may transition in a substantially graduated manner or be of a substantially linear progression between the different bores or internal diameters between each end of the first and second ends  902 ,  904 . Such a transitioned lumen  912  (or flow passage) can help to minimise or reduce resistance to flow of gases therethrough. A substantially smooth inner wall or surface of the lumen  912  can further assist with minimising such resistance to gas flow. 
     When the adapter insert  900  is located within a port of a filter housing, the shank portion  905  is advantageously substantially housed within or by that particular port. Located along or about the shank portion  905  may be one or more splines or ribs  906 . In particular embodiments, the one or more splines or ribs  906  can extend longitudinally along the shank portion  905 . In alternative embodiments, one or more of the splines or ribs  906  may be provided as circumferential (whether as a continuous or discontinuous feature) or radially extensive ribs. Whether the splines or ribs  906  are of a longitudinal or circumferential orientation, in some configurations the one or more splines or ribs  906  can extend a radial distance outward from the shank portion  905  so as to at least partially engage or make surface contact with an inside surface  907  of a port into which the adapter insert  900  is to be located. 
     The or each of the one or more splines or ribs  906  can be configured to provide at least some strengthening or structural support to the wall of a port into which the adapter insert  900  is to be located. This may be particularly useful in instances where the port from a filter housing may benefit from structural or strengthening, particularly when such a filter (and the filter housing) is being utilised for the purposes as disclosed herein. 
     The splines or ribs  906  can provide for a taper-type fitting of the shank into a port of the filter housing. In this way, such a taper-type fitting can help with an improved fit of the adapter insert into the port. The splines or ribs  906  can be tapered in a direction so that the there is a greater or larger tolerance between any such splines or ribs  906  and an internal surface (e.g. wall) of the port toward the second end of the adapter insert  904 , and a much smaller tolerance (or tighter fit) between the splines or ribs  906  and the port wall or internal surface at the first end of the insert  902 . 
     The splines or ribs  906  extending from the shank portion  905  may further assist in holding the adapter insert  900  in place relative to the filter housing port into which the insert is to be located and may also provide stability for the adapter insert. 
     In still further embodiments, the adapter insert  900  may additionally comprise one or more sealing members  908 , or two or more sealing members, or in particular instances there may be two sealing members. 
     Advantageously, at least one first sealing member  908 A may be provided about the shank portion  905 . Such a first sealing member  908 A can be provided about a circumference or a radial region of the shank portion  905 . Such a first sealing member  908 A facilitates a first sealing surface which extends radially outwardly from the shank portion  905 . Where additional first sealing members are provided about or along the shank portion  905 , these further first sealing members provide for additional sealing surfaces which may contact and/or form a seal with an inside surface  907  of a port into which the shank portion is to be housed. 
     As shown in the figures, the or each said first sealing member  908 A is located intermediate of the first end  902  and the second end  904  of the adapter insert  900 . In one particular embodiment, a first sealing member  908 A is located substantially half-way along the shank portion  905 , and provided as a circumferential seal of an o-ring type. 
     In another embodiment, the adapter insert  900  may provide for at least the first sealing member  908 A provided about the shank portion  905  and at least a second sealing member  908 B provided substantially at or adjacent with a first end  902  of the adapter insert  900 . 
     The first sealing member  908 A may help to account for any gaps between the shank portion  905  or the splines and ribs  906  and an inside wall portion of the port into which the adapter insert is to be located. In addition, the first sealing member  908 A can help form a pneumatic seal between the adapter insert  900  and a port of the filter housing  703  by sealing against inside surface  907 . Such a first sealing member  908 A can provide for a more malleable seal than an interference fit on its own between the adapter insert and the port into which it is placed. 
     In one embodiment, the sealing members  908  may be positioned upon the adapter insert  900  by a suitably shaped recess or groove  908 C. For instance, first sealing member  908 A may be housed in a recess or groove  908 C in shank portion  905  such that the two walls of the groove  908 C secure the sealing member  908 A in place. However, it will be appreciated alternative systems may be utilised as part of further embodiments for maintaining the orientation or positioning of the different sealing members  908  upon the adapter insert. 
     In another embodiment, the shank portion  905  of the adapter insert  900  may be sized to form a pneumatic seal with the inside wall portion of the port into which the adapter insert is to be located. The shank portion  905  can be sized as to form an interference fit with the insider surface  907 . 
     At least one second sealing member  908 B can be provided or located substantially at or adjacent with the first end  902  of the adapter insert  900 . For example, in one embodiment, such a second sealing member  908 B can be located or positioned to be substantially at or adjacent with a base  909  of the male connection fingers  901 . The base  909  being at an end of said male connection fingers  901  which extends from the first end  902  of the adapter insert  900 . 
     The second sealing member  908 B can operate or acts to create a pneumatic seal with a surface of a female connector (for example, at least one or more of an inside surface, an end face or a chamfered-type face of the female connector when brought to bear upon the second sealing member.) The O-ring may be preferred over just an interference fit seal because of the higher pressure when put into engagement or surface contact with the second sealing member and/or the male connection fingers  901 . Such a second sealing member can help provide for a better pneumatic seal with a female connector than an interference seal on its own, although an interference fit on its own is not precluded. 
     In further embodiments, the first end  902  of the adapter insert  900  may additionally comprise a radially extensive ledge or lip  910 . In these embodiments, a second sealing member  908 B can be located or positioned to be substantially upon an upper-side surface of the ledge or lip  910 . 
     Such a ledge or lip  910  can extend radially outwardly so as to be of an outside diameter that is equal to or less than the outside diameter of a port within which the adapter insert  900  is to be located. The ledge or lip  910  can be of an outside diameter that is greater than an inside diameter of the port within which the adapter insert is to be located. 
     The particular maximum outside or external sizings or dimensions of the adapter insert  900  (exclusive of the first sealing member  908 A) may help and mean that even if the adaptor insert  900  were to be put into connection with filter housing port, a 22 mm female taper connection or another component can fit over the adapter insert  900  and onto the outside surface of the port to which the adapter insert is housed or located in-use (for example, in this situation, the outside diameter of the filter housing port would effectively be working as a 22 mm male taper fitting). In emergencies, this can mean that other systems can be connected to the filter housing quickly and without having to remove the adaptor insert itself. 
     An underside surface  911  of said ledge or lip  910  is enabled for contact with a terminal end face (such as that surface labelled as item  713 ) of the port within which the adapter insert  900  is to be located. 
     Accordingly, the underside surface  911  may perform as a stop end surface to prevent an over-insertion of the adapter insert  900  into the filter housing  703  through a port. Similarly, the retention members  903  can perform as stop ends or other features for preventing the inadvertent removal or detachment of the adapter insert  900  from a port into which it is inserted. In this manner, the adapter insert  900 , once provided in connection or retention with the component or port into which it is insert, may be permanently retained or attached. 
     In various arrangements, a distance between the underside surface  911  of the ledge or lip  910  and a retaining member  903  can match or may be substantially equal to the length of the port into which the adapter insert is to be located. 
     The ledge or lip  910  can be interposed, or may be sandwiched, between an end of the shank portion  905  and a first end  902  of the adapter insert  900 . Alternatively, the ledge or lip  910  may be sandwiched between the base  909  of the male connection fingers  901  and an end (e.g. the first end  902 ) of the shank portion  905 . In particular configurations, the at least one second sealing member  908 B is sandwiched between the base  909  of the male connection fingers  901  and an end of the shank portion  905 . Alternatively, the at least one second sealing member  908 B may sandwiched between the base  909  of the male connection fingers  901  and an upper-side surface of the ledge or lip  910 . 
     Advantageously, when used, the at least one second sealing member  908 B provides for a second sealing surface for sealing with a surface of another component (such as a connector or a port of another connector) when brought to bear upon the second sealing surface. The or each second sealing member  908 B can be of an o-ring type. 
     In relation to the second sealing member  908 B, when another component is brought into connection or engagement with the male connection fingers  901  and, in use, when such a connection or engagement is made between these, the another component may be configured to additionally engage with the second sealing member and its provision of a second sealing surface. In this manner, the second sealing member can operatively assist with a pneumatic connection being made between the adapter insert and the another component. This can help with improved pneumatic connections, reduction in loss of gas from the breathing circuit and the associated benefits of improved/maintained delivery of a desired therapy to an end user or patient. 
     The adapter insert  900  as described herein, and when considered exclusive of a first sealing member(s), may have a maximum radial outside diameter (or external profile) which is equal to or less than 22 mm. 
     The above embodiments and configurations therein gives reference to ‘another component’. Such ‘another component’ may be any other suitable component to which a connection may be made, particularly as part of a medical breathing circuit. However, it is contemplated that particularly preferred is for the ‘another component’ to be an end connector provided as a part of another section of a medical breathing circuit. 
     For example,  FIG.  6 N  illustrates an exploded perspective view of a filter housing  703 , an adapter insert  900 , and an another component  805 .  FIGS.  6 E and  6 F  illustrate a filter housing with an adapter insert in-situ (only the side of the ledge or lip  910  being observable in  FIG.  6 F ) and a connection made with an another component  805 .  FIG.  6 E  is a cross-section view through  FIG.  6 F . 
     Each of  FIGS.  6 G-M  illustrate the adapter insert  900  independently. 
     For example,  FIG.  6 G  is a first side view of the adapter insert  900 , which includes a single first sealing member  908 A and a single second sealing member  908 B.  FIG.  6 I  is a cross-sectional view of  FIG.  6 G  which helps illustrate the relative positioning of different sealing members  908 .  FIG.  6 I  is also a cross-sectional view of  FIG.  6 H  along D-D.  FIG.  6 H  is a view of the adapter insert  900 , axially rotated through 90° from that of  FIG.  6 G . 
       FIG.  6 J  illustrates the adapter insert  900  in the same orientation as that of  FIG.  6 H , yet helps show the insert  900  prior to sealing members  908  being put into place.  FIG.  6 K  illustrates the same adapter insert  900  as that of  FIG.  6 J , yet is axially rotated through 90°.  FIG.  6 K  is a cross sectional view of  FIG.  6 J  along E-E. 
     Each of  FIGS.  6 L and  6 M  illustrate an adapter insert  900  in different end perspective views. 
     An adapter insert  900  such as has been described herein can be put into engagement with a port of a variety of different components, in particular however, provision of an adapter for a filter housing is desired. The provision of such an adapter allows for an in-line connection to be made with the filter body by a component of a breathing circuit. Accordingly, an in-line filter can be more readily and easily (as well as accurately and pneumatically) put into the gas flow path of a medical breathing circuit. 
     Exemplary Nasal Cannulae 
       FIGS.  7  to  21    show exemplary configurations of nasal cannulae that can be used in the patient interfaces  601  of the apparatuses described herein. It will be appreciated that the filter  501  will be provided upstream of the nasal cannula and downstream of the inspiratory conduit. 
     The nasal cannula assembly provides a patient with a patient interface suitable for the delivery of high airflow, high humidity gas flow to the patient&#39;s nasal cavity. The nasal cannula is useful in the anaesthetic context, because the cannula has a relatively small footprint and is positioned on the upper lip, leaving the mouth and throat free for a surgeon to insert additional instruments with minimal obstruction or interference or to perform procedures on the mouth/throat with minimal obstruction or interference. For patients to accept use of nasal cannula under these circumstances the cannula need to be unobtrusive, comfortable to wear, noise free, suitable for wearing while sleeping. The cannula may also be used for other therapies such as for Continuous Positive Airway Pressure (CPAP) therapy and the like. 
     A first form of the nasal cannula assembly  30 / 607  is shown in  FIGS.  7  and  8   . This nasal cannula, generally indicated as  20 , comprises a face mount part  21  including a pair of tubular nasal prongs  22 ,  23  integrally molded with or removably attached to the face mount part  21 , and a gases flow manifold part  24  that is integrally molded with or attached to tubing  603 , such as that described above. 
     As described above, a nasal cannula can be provided with a removably attachable manifold for delivering the flow of gas to the interface, the manifold able to be re-oriented so as to have a gas supply connection put to either a left or a right side of the interface (or the patient). One or pair of side arms of such a nasal cannula allow for the positioning of the interface on a patient&#39;s face and may optionally include a relatively soft outer material or overmoulded material in at least the patient contacting surfaces. 
     The removable manifold may be re-oriented as previously described. Such a re-orientation can be manually done by a user or a person assisting the patient/user. 
     A headgear as disclosed herein may be provided in combination with the nasal cannula and may include at least one strap of which is bifurcatable (i.e. may have a line of weakness or other pre-defined zone allowing a user to separate the strap into two parts). 
     The body of the nasal cannula may include a barrel shaped portion into which the manifold is inserted and can be removed therefrom to allow for side swapping. The nasal cannula may additionally or optionally include headgear connectors that connect to one or both side arms. 
     The face mount part  21  and prongs  22 ,  23  may be moulded from silicone or other flexible material as is known is the art of cannula construction. The gases flow manifold part  24  may be made from a hard plastics material, although it may be manufactured in other suitable materials. 
     The face mount part  21  may be integrally molded with the prongs  22 ,  23  and is shaped to generally follow the contours of a patient&#39;s face around the upper lip area. The inner side (not shown) of the face mount part  21  may be provided with a breathable pad, to be described below. The outer side  25  of the face mount part  21  has moulded in it an elongated oval recess  26  and two oval recesses  27 ,  28  that extend through the face mount part  21  and each meet the tubular passageway&#39;s formed within each of the tubular prongs  22 ,  23 . 
     The gases flow manifold part  24  is generally tubular in shape having a substantially circular inlet (not shown) on one side that curves around to an elongated oval outlet  29 . The circular inlet receives the end of the conduit or tubing  603 , so that gases are supplied to the gases flow manifold part  24  and are able to flow through the inlet and out the outlet  29 . The tubing  603  may be permanently fixed to the manifold part  24 , or may be releasably attachable. 
     The outlet  29 , being elongated and oval in shape, fits into the elongated recess  26  in a friction or snap fit engagement with the manifold  21 , such that a substantial force is required to remove the manifold part  24  from the elongated recess  26 . Further, as the face mount part  21  is flexible and the manifold part  24  made from a harder plastics material it is possible for the manifold part outlet  29  to be easily pushed or forced into the elongated recess  26 . When the manifold part  24  is engaged with the face mount part  21  and in use, gases flow from the tubing  603 , through the gases flow manifold part  24  out its outlet  29 , into each of the oval recesses  27 ,  28 , into each of the prongs  22 ,  23  and into the patient&#39;s nares. 
     The face mount part elongate recess  26  and manifold part outlet  29  are symmetrical in shape and configuration and therefore the manifold part  24  is capable of being switched or flipped such that the tubing  603  extends from either the left or right side of the patient&#39;s nares. This means that the nasal cannula assembly  20  and associated tubing  603  are relatively unobtrusive as the cannula  20  only requires a single horizontal side entry, not two entries. 
     The nasal cannula assembly is more comfortable to wear as it sits under the septum of the nose and supports the two nasal prongs. As the prongs are made in one moulding of a soft material such as silicone the prongs are easy to insert in the patient&#39;s nares and comfortable to the patient. 
     The face mount part  21  is contoured such that the pressure distribution within the face mount part  21  forces even airflows up each nasal prong in order to reduce whistling of the airflow. 
     Reference is now made to  FIGS.  9  to  12    that show a second form of nasal cannula assembly. In this form the nasal cannula assembly  30 / 607  is of a substantially similar form to the first nasal cannula assembly of  FIGS.  7  and  8   , and has a face mount part  32 , a pair of nasal prongs  33 ,  34 , gases flow manifold part  35 , and tubing  603 . The face mount part  32  and pair of nasal prongs  33 ,  34  may be integrally moulded as one piece from a soft plastics material such as silicone, although in other forms the face mount part and prongs may be separate, but capable of attachment together for use. 
     The nasal prongs  33 ,  34  are tubular in shape and may be consistent in diameter but may be shaped to fit the contours of the human nares. 
     A strap or strap attachment means  31  may be integrally formed or attached to the face mount part  32  in order to enable the nasal cannula assembly  30 / 607  to be held in place about a patient&#39;s face. 
     The face mount part  32  has an open tubular recess  38  extending below the nasal prongs  33 ,  34  that is capable of receiving a gases flow manifold part  35  that is attached to or integrally formed with tubing  603 . The tubular passageways within the nasal prongs  33 ,  34  extend through the face mount part and into the recess  38 . The gases flow manifold part  35  is blocked at one end  39  but attached to the tubing at the other end and has an elongate opening  37  that acts as an exit for gases received from the tubing  603 . Due to the flexible nature of the material the face mount part  32  is made from, and as the gases flow manifold part  35  is made from a hard plastics material, the gases flow manifold part  35  can be pushed through the tubular recess  38  in the face mount part  32  and the elongate opening  37  in the gases flow manifold part  35  meets with the tubular passageways of the prongs  33 ,  34 . Therefore, in use, gases flowing through the tubing and into the gases flow manifold part  35  exit through the opening  37  and into the tubular passageways in the prongs  33 ,  34 , then into the patient&#39;s nares. 
     In order to assist with maintaining the gases flow manifold part  35  within the manifold recess  38  the manifold part  35  is provided with an inner recessed portion  60  and contoured lip areas  58 ,  59 . When engaged with the face mount part  32  the tubular body forming the recess  38  sits within the inner recessed portion  60  and the edges of the tubular body abut the lips  58 ,  59  formed on the manifold part  35 . 
     An optional breathable pad may be supplied with any of the nasal cannula assemblies described above. In particular, such a pad  36  is shown in  FIG.  12    in the second form of the nasal cannula assembly as described above. 
     The pad may be attached to the inside surface of the face mount part  32  that connects with the upper lip of the patient wearing the cannula. The pad  36 , which may be made from an absorbent cloth, reduces the incidence of heat and moisture on the patient&#39;s upper lip, where the face mount part  32  sits against their face. 
     The pad  36  may be attached to the face mount part  32  by adhesive, for example, the pad could be supplied with a sticky backing that adheres to the face mount part, so that the pad can be easily removed from the face mount part and replaced as necessary. 
     The pad, if provided, reduces the effects of heat against the patient&#39;s skin and improves hygiene, as any contaminants or cultures that may grow close to the patient&#39;s skin, in the warm environment can be removed on removal and replacement of the pad. 
     Referring now to  FIGS.  13  to  16   , a third form of the nasal cannula assembly is shown where the nasal cannula assembly comprises three parts. 
     Firstly, a gases flow manifold part  40  is shown in  FIG.  13    which is designed for either left or right hand orientation and provides a symmetrical flow to a pair of nasal cannula assembly prongs  41 ,  42  (see  FIG.  15  or  16   ). 
     Next, a pair of soft nasal prongs  41  or  42  are provided that are capable of being attached to the top of the gases flow manifold part  40  allowing for a large range of different shaped and spaced prongs to be available to the patient. Two such configurations of prongs  41 ,  42  are shown in  FIGS.  15  and  16   . The prongs  41  of  FIG.  15    are narrow elongate tubular members  43 ,  44  of a substantially constant diameter that are fittable into a patient&#39;s nares. The prongs are integrally molded with a body  45  that is fittable with the gases flow manifold part  40  (see  FIG.  13   ) by appropriate means, for example, friction or snap fit. The prongs  42  of  FIG.  16    are tapered tubular members  46 ,  47  moulded to a body  48 . Again, this body  48  is capable of being fitted (friction, snap or other) to the gases flow manifold part of  FIG.  13   . These prongs may be made from a soft plastics material such as silicon, although other suitable materials may be used. 
     With the prongs being removable they are easily cleaned and could also be disinfected for second or subsequent use for a particular patient. 
     The third part to the third form of the nasal cannula assembly shown in  FIGS.  13  to  16    is the face mount part  49  of  FIG.  14   . The face mount part  49  comprises a head strap  53  attached to a pad  50 , that may be a moulded or shaped substantially rigid pad, for example, made from a plastics material such as polypropylene. The pad  50  as shown in  FIG.  14    may include a breathable cloth pad on its surface that abuts a patient&#39;s face, similar to that pad  36  described in relation to  FIG.  12   , or the head straps  53  may extend to sit behind the pad. The head strap  53  may be made from a flexible material, such as neoprene. 
     The plastic pad  50  is shown in  FIG.  14    and has a plurality of apertures  61  formed into to allow for heat and moisture to dissipate from the patient&#39;s facial surface. The pad  50  has fastening means  51 ,  52  for holding the gases flow manifold part  49  in the correct position on the upper lip of the patient. The fastening means may be clips  51 ,  52  that are fittable into complimentary recesses  54 ,  55 ,  56 ,  57  provided in or on the manifold part  40  (see  FIG.  13   ), but other appropriate fastening means may be provided with the cannula. An example of other fastening means is a loop that is integrally moulded as part of the prongs which wraps around the face mount part and latches over a protrusion on the manifold part thus encapsulating the face mount part and holding the assembly together stably and securely. Another example of a fastening means is a plastic Velcro™ type attachment where one side would attach to one side of the manifold part  40  and the other side to the plastic pad  50 . For the fastening means shown in  FIGS.  13  and  14    at least one recess must be provided on either side of the manifold  40 . In the preferred form of the nasal cannula assembly two recesses  54 ,  55  are provided on one side of the manifold  40  and two other recesses  56 ,  57  on the other side of the manifold  40 . 
     The attachment between the face mount part  49  and the manifold part  40  allows for either left or right hand orientation of the manifold part and associated tubing. 
     The cannula may be disposed after use. Alternatively, the cannula could be stored and the cannula subsequently re-used on a single patient, for example when a patient is moved from an operating room to a recovery room. The cannula can be removed and stored until it is needed in recovery. With a single flow entry cannula there will be less condensate due to the reduction in surface area for heat loss and thus the cannula reduces the effects of condensation building in the tubing and cannula. 
     Often an unheated flexible section of tubing is placed proximal to the patient to reduce torsion or pulling on the patient interface and reduce possible heat problems or over heating close to the patient. In order to reduce condensate forming in the unheated tubing, tubing can be provided that has vapour transmission properties. Referring now to  FIG.  17    the nasal cannula (in particular that of the second form described herein) may be provided with a short piece of breathable tubing  603  between the nasal cannula  30 / 607  and heated inspiratory conduit  401 . A filter will be provided between 603 and 401 as described above. The tubing  603  may be made from a material that allows for transmission of water, such as a hydrophilic material, for example SYMPATEX™. 
     Test results show the performance of a 420 mm length of breathable tube, operating with air input at an absolute humidity of 42.2 mg/L, an airflow of 10 litres per minute (LPM), in a room with ambient air at 22° C. and 50% RH, only lowered the absolute humidity to 41.15 mg/L at the exit of the dry tube. In comparison a 420 mm length of non-breathable but insulated polyethylene tube under exactly the same conditions also output air at 41.15 mg/L. In the breathable tube there was significantly less condensate measured, therefore, some of the humidity that would otherwise be lost as condensate on the wall is being transmitted through the breathable wall. 
     The result of providing the short section of breathable tubing  603  is that a majority of humidity in the gases is transported to the patient, and there is an insignificant and immeasurable loss of humidity through the breathable wall of the short tube  603 , while condensate is reduced. The design of the high airflow high humidity system has been optimized to deliver a breathable gas treatment to patients at temperatures approximating body temperature and fully saturated with water vapour. The use of an unheated breathable conduit proximal to the patient to provide a connection that is highly flexible and avoids condensation by breathing would be expected to lower the humidity of the gas treatment thereby decreasing the efficacy of the treatment. These results are surprising and are counterintuitive and go some way to explaining why the use of a breathable tube as a short section of tubing before the patient has been overlooked. This short tube  603  is envisaged to be used with any tube delivering heated and humidified gases to a patient. 
     In an alternative configuration, a neck tie or lanyard may be provided with the nasal cannula assembly.  FIG.  17    shows such a tie  63 . The tie  63  may be connected to the tubing  401  or  603 , or to the filter  501  (not shown in this Figure). A toggle  64  may be provided with the neck tie  63  in order to adjust the neck tie&#39;s length. The neck tie has the purpose of taking some of the weight of the tubing  401  and prevents the weight of the tubing  401  pulling on the nasal cannula assembly  30 / 607 . This helps to prevent the prongs from interfering with the very sensitive lining of the nasal passages or from being dislodged. The loose fitting neck tie also provides a convenient way of connecting the tubing  401  to the patient outside the blankets. This allows the patient to turn in the bed and avoids the tubing  401  overheating if placed under the blankets. 
     The tie or lanyard described may be used with any breathing apparatus or interface that supplies gases to a patient; for example it may be used with a nasal or face mask or with a tracheostomy fitting or connector. When the tie or lanyard is used with such apparatuses or interfaces it takes the weight of the conduit(s) or tubing supplying gases to the mask, connector or cannulae and helps reduce the pull on the mask, connector or cannulae. 
       FIGS.  20  and  21    show a tracheostomy fitting or connector that may utilise a neck tie or lanyard. The tracheostomy fitting may be used as the patient interface in the kit and apparatus described herein, in place of the nasal cannula. Again, a filter, such as the filter  501 , would be provided between the patient interface (in this case for example the tracheostomy connector  69 ) or the conduit  71  and the inspiratory conduit  401 . In one particular example a particularly advantageous arrangement includes such a filter  501  being adapted by an adapter insert  900 , thereby facilitating an ease of connection by the conduit  71  to the outlet of the filter  501 . The tracheostomy connector  69  attaches to a tracheostomy mount  72  that extends into a tracheostomy tube (not shown) through hole in a patient&#39;s  68  neck and into their airway passages. The connector  69  provides a direct coupling of a tracheostomy tube to the breathing supply of gases received through a conduit  71 . The conduit  71  may be constructed in a breathable material, similar to that described above, but may be a heated tube. 
     The connector  69  has the conduit  71  attached directly to it and also includes an expiratory port  70  to allow for expiration of gases. On inspiration no gases flow occurs out the port  70  due to the flow of gases to the connector  69  being greater than a patient&#39;s peak inspiratory flow. Therefore, there is also no or very little entraining of gases from the ambient air. 
     Excess weight on the tracheostomy tube may cause excess movement of the tube, with the risk of complications such as displacement or re-cannulation of the tracheostomy, the formation of granulation tissue or more seriously, stomal erosion. To obviate or reduce these problems a tie or lanyard  73  can be connected to the conduit  71  or additional connector  74  (that may for example connector the conduit  71  to an additional conduit  75  that supplies gases). The tie or lanyard  73  transfers the weight of the conduits  71 ,  75  and connector  74  from the tracheostomy tube or mount  72  and distributes it onto the neck of the patient leaving a minimal load directly on the tracheostomy tube or mount  72 . The tie or lanyard  73  may be adjustable so that the tie or lanyard length can be altered to suit a patient&#39;s requirements. Alternatively, headgear can be used to retain the tracheostomy tube. The tracheostomy tube can be used to provide high flow therapy. In some configurations, the tracheostomy tube has a leaky connection with the patient to reduce the chance of barotrauma or over-pressurisation of the lungs when using high flow. 
     Orientation of a nasal cannula is an important requirement for patient comfort. If the nasal cannula is not held firmly in position, it can skew, placing unwanted load on the inside surfaces of the patient&#39;s nares. However, to overcome this head gear is often provided with nasal cannula, although, if the head gear is not tight the nasal cannula can still move. This type of tight tension can then compromise patient comfort with pressure on the head and face, while forcing the cannula further up the patient&#39;s nose. Ideally nasal cannula should attach to the patient&#39;s face in a secure manner, yet with low loading on the head and face. 
     Referring to  FIGS.  18  and  19    nasal cannula attachment means may be provided to hold the nasal cannula assembly  30 / 607  to the patient&#39;s face. The attachment means may be ear loops  65 ,  66  that are connected to the straps  31  of the face mount part  32  of the nasal cannula assembly  30 / 607 . 
     The loops  65 ,  66  extend from the face mount part  32  around the patient&#39;s ears, and provide rigid anchoring when an inelastic material is used. The loops  65 ,  66  may be made from a thin, round cord with the ends captured in plastic, and may be adjustable. The plastic ends of the loops  65 ,  66  are inserted into purpose made cavities in the straps  31 , enabling adjustment of length for a comfortable, yet firm fit. 
     In use, to fit the nasal cannula assembly, a first loop (for example, loop  65 ) is placed over one ear, the nasal cannula assembly positioned on the patient&#39;s face and in their nose, then the other ear is passed through the second loop (for example, loop  66 ), so both loops sit snugly behind the ears. This method of fitting the nasal cannula avoids the initial discomfort of gases being blown into the patient&#39;s eyes when the cannula assembly is pulled down the face for fitting with other headgear. Fastening the nasal cannula in this method provides an attachment means that is horizontally secure with minimum tension applied to the ear connection loops. The ear loops have the added advantage for a patient lying on their back that there are no straps behind the back of the head that are moved by head movement on the pillow. 
     The conduits described herein may be formed from tubing. The tubing configurations may be suitable to deliver gas at a high flow rate as described herein. For example, at flow rate of between about 45 and 150 liters per minute (LPM), or between about 10 and 120 LPM, or between about 60 LPM and about 80 LPM, or at about 70 LPM. 
     The complementary coupling features between the components of the apparatus could be any suitable form. For example, the features could be any one or more of push fits, interference fits, latch/catch-style fittings, bayonet-style fittings, and medical tapers or medical connections. In one example, the coupling features between all components may be a 22 mm medical taper. Soft seals, such as O-rings, may be provided between the ports of the components to provide a seal at the connections or connection points. Different types of coupling features may be used to connect different components, so that there is only one possible assembly configuration of the components in the system. In another form, the complementary coupling features may be provided, at least for one side of the coupling, by an adapter insert, such as that labelled as item  900 . 
     The gas used in the configurations described above will typically be oxygen. Alternatively, the gas could be air or other suitable gas(es). 
     The liquid used in the configurations described above for humidification will typically be water. Alternatively the liquid could be other liquid(s) suitable for a humidification process. 
     The apparatuses, kits, and methods disclosed herein are particularly beneficial in an anaesthetic setting. The described configurations enable the same inspiratory conduit (and upstream components) to be used for a number of patients while only swapping out the patient interface/filter combination. 
     In an anaesthetic setting, the inspiratory conduit and patient interface need to be swapped for each patient due to an infection risk. In the anaesthetic process, the time of use of the inspiratory conduit is significantly shorter than for other ventilation applications. Ventilation may occur for days of therapy, while anaesthetic operations typically only last for a maximum of several hours. Hence, having the filter in-line with the cannula allows a user to re-use the inspiratory conduit (and upstream parts such as the humidifier chamber and gas delivery conduit) on subsequent patients. This is complementary to existing practice. 
     In an anaesthesia setting it is not uncommon to observe the anaesthetic breathing circuits, which attach an anaesthetic system to a patient interface, being reused between patients during a day of surgeries. A filter may be placed between the circuit and patient interface to minimise the risk of infection, with the filter and patient interface being replaced for each patient. A package or kit can be provided, as described herein, to provide for components to be used for such a circuit, with some components being individual to a particular patient (i.e. the components are only used by a single patient), yet other components (such as components upstream from such a filter, including but not limited to an inspiratory conduit and optionally a humidifier chamber). 
     With the advent of nasal high flow and its intended use in the anaesthesia setting via a respiratory breathing circuit separate to the anaesthetic breathing circuit, it is conceivable the respiratory breathing circuit would be reused. Respiratory therapy circuits like the ones used during nasal high flow are typically single use items. One of the reasons for this is to prevent contamination from one patient to another when the same flow source and/or humidifier are used. 
     The following embodiments relate to further alternatives for preventing contamination and infection to allow for the reuse of respiratory breathing circuits between patients during anaesthesia applications. However it should be noted these ideas are not exclusive to anaesthesia. It is conceivable the embodiments described below may be used in a general respiratory setting such as CPAP therapy to allow for reuse of breathing circuits in any application. 
     In some embodiments a filter may be used to prevent patient contamination of a breathing circuit. A filter may be a mechanical filter, to capture particles by direct interception. Alternatively, a filter may be electrostatic, to capture particles by electrical attraction. In other alternatives, the filter may be hydrophobic, so that the filter repels water and does not promote microbial growth. The filter should allow for air and water vapour (i.e. humidity) to pass through the filter without compromising filtration of infectious matter and condensate. In various examples, filter materials or filter media composition may comprise one or more of the following: Mineral fibres, Glass fibres, ceramic fibres, polypropylene, expanded polytetrafluoroethylene (PTFE), acrylics including modacrylics and thermoplastic polyurethane (e.g. Estane), cellulose fibres, or electrostatic fibres. Other filter materials or media have been described in this specification and those media or materials or particular characteristics or properties are re-iterated here. 
     A filter may be provided at a connection point between a patient interface (such as, but not limited to a nasal cannula or a nasal mask) and a respiratory breathing circuit. For example, a filter may be provided as a component to be inserted into an end of a conduit forming part of a respiratory breathing circuit, or as a component to be inserted into a patient interface to be connected to a breathing circuit. 
     With reference to  FIGS.  22 A to  22 E , a filter connector or component  1010  comprises a filter or filter element  1012 . In  FIGS.  22 A to  22 E , the component  1010  is a connector adapted to connect between a main conduit of a breathing circuit and a patient interface or a patient interface tubing, having the same diameter as the main conduit. It will be appreciated some embodiments may utilise an interface tubing that has a smaller diameter than the main conduit. In other embodiments, the filter could be concentric with the main conduit and be designed to have the same diameter as the main conduit and interface or nasal cannula connections on either side. The filter or component comprising a filter or filter element may even be substantially elongated to facilitate the same filter material contact surface area as a substantially larger diameter design. 
     Thus, the component  1010  may comprise a union or socket connector or a reducing union or socket connector or adapter  1011  including a filter  1012 . A reducing union or socket connector or adapter has one end (e.g. inlet) of a first diameter and an opposite end (outlet) of a second diameter, wherein the first diameter is greater than the second diameter, or diameters as necessary to operate with the components to which it must be fitted. 
     As illustrated in  FIG.  22 A , the filter  1012  may comprise a sock filter. Alternatively, as illustrated in  FIG.  22 B , the filter  1012  may comprise a stacked disc filter. Still further, as illustrated in  FIG.  22 C , the filter  1012  may comprise a spiral filter. Yet further, as illustrated in  FIG.  22 D , the filter  1012  may comprise a pleated sheet filter. In other alternatively, the filter  1012  may comprise a block of filter material. In another alternative, as illustrated in  FIG.  22 E , the filter  1012  may comprise a disc  1012   a  of filter material with streams of material  1012   b  free floating from or off the disc in the fluid flow. The free streaming material may vibrate at high flows, aiding in filtration. The streams may contain small holes to capture particulate. 
     As for example illustrated by  FIGS.  22 A to  22 D , the filter  1012  is provided with a connector  1011  for connecting between a patient interface and a conduit of the respiratory breathing circuit. The filter  1012  may be provided as a separate filter element to be inserted into or attached to a conduit and/or patient interface. For example, the filter of  FIG.  22 E  may be inserted into an end or a conduit and/or an inlet of a patient interface, and the interface and the conduit adapted to fit together to be in fluid communication, or may be integrated into the interface or as part of an interface arrangement itself. 
     In still further examples, a patient interface tube (e.g. item  1017   FIG.  26 A ) may be made from an open cell foam material with a sealing skin, such that the interface tube is breathable in that it allows water vapour to pass through it but does not allow the passage of liquid water or bulk flow of gases. In some embodiments the patient interface is a nasal cannula comprising one or two nasal prongs to fit into a patient&#39;s nostrils. In such an embodiment, each prong may provide a filter. 
     In some embodiments a filter in combination with a valve may be used to prevent patient contamination of a breathing circuit. For example, in some embodiments a filter component may comprise a one way valve  1013  and a filter attached to an outlet of the one way valve. In some embodiments the one way valve may be a duck bill valve. As illustrated in  FIGS.  23 A and  23 B , an expanding filter material may be attached to the duckbill end of the valve, so that as the valve opens the filter material expands to allow flow through the valve and filter material and prevent contamination passing back through the valve. 
     In some embodiments a disinfectant may be used to kill or remove infectious matter in a breathing circuit, or alternatively reduce the level of infectious matter to a safe level. In this specification and claims, the word “prevent” should be interpreted to have an equivalent meaning to “reduce to acceptable levels”. Some examples of some possible disinfectants (in liquid or gas form) may be ortho-phthalaldehyde, glutaraldehyde, hydrogen peroxide, and nitrogen dioxide. 
     In some embodiments, a disinfectant may be distributed into a breathing circuit via a disinfection reservoir that releases disinfectant when a circuit is not in use on a patient. For example, as illustrated in  FIGS.  24 A and  24 B , a disinfection capsule  1014  that caps an end of the breathing circuit  10100  may be provided. The capsule may have a push button  1015  for release of disinfectant ( FIG.  24 A ). The capsule  1014  could be built into the breathing circuit or may be a separate component that a user inserts into an end of the breathing circuit as illustrated. In some embodiments a reservoir may be provided in the walls of a conduit of the breathing circuit or a connector of the breathing circuit, and be released through one way valves into the breathing circuit via a release mechanism. The release mechanism may be actuated by an electric signal that is generated when a patient interface is removed from the circuit. In some embodiments a flushing disinfection unit may attach to each end of the breathing circuit. The disinfection unit may be used to alternately flush the breathing circuit with water or disinfectant. The flushing disinfection unit may be a separate unit or may be built into the humidifier. 
     In some embodiments, a breathing circuit maybe disinfected by providing radiation (for example ultraviolet light or near infrared ultra-short pulsed laser) to the breathing circuit to inactivate microorganisms. As illustrated in  FIG.  25 A , in some embodiments a sheet of radiation  1020  may be delivered at a connection point between a breathing circuit and a patient interface. For example, in some embodiments a radiation source may be built in to a connector  10100  at an end of a conduit of the breathing circuit. In some embodiments radiation may be provided as individual radiation beams built in throughout the circuit, or delivering radiation in beams and or sheets throughout the circuit. In some embodiments radiation is delivered to the breathing circuit continuously including during use of the circuit by a patient. In some embodiments radiation is delivered to the breathing circuit only when a patient interface is disconnected. In some embodiments a radiation source may be built into humidifier or other hardware of a respiratory breathing system upstream of the breathing circuit that connects with an end of the breathing circuit. 
     In some embodiments heat disinfection may be used to kill microorganisms in the breathing circuit. For example, in some embodiments a conduit of the breathing circuit may comprise heating wires or heating elements to prevent ‘rain out’ or condensation forming in the conduit. In some configurations heating elements such as wires may be positioned in the gases flow, inside the conduit. For example the heating elements may be laid through a lumen of the conduit, or may be placed against or fixed to an inner wall surface of the conduit. In some configurations heating elements may be integrated within a wall of the conduit, or may be wrapped around an outside surface of the conduit. Heating elements may be co-molded in the wall of the conduit, or may be clipped or bonded or otherwise held in place inside or outside the conduit. In a disinfecting cycle heat may be delivered to the breathing circuit by increasing the heat output of the breathing circuit heating elements for a period of time between patients (with or without the gas flow running) to kill microorganisms. 
     In some embodiments, a disinfection unit may be used that attaches to each end of the breathing circuit and disinfects by cycling hot water (e.g. at 90° C.) and detergent through the breathing circuit. The disinfection unit could be separate or built in with any other hardware (for example a humidifier) upstream of the breathing circuit. Alternatively the disinfection unit may be downstream of the breathing circuit. In some configurations the disinfection unit may be built in with a gases source, for example a blower unit. In some embodiments a heated collar may be provided at a connection point between the breathing circuit and a patient interface to stop infectious matter migration from the patient into the breathing circuit. In some embodiments, one or more filters and/or valves described above may be used in combination with a breathing circuit and disinfection unit or disinfection method described here. In some embodiments, a connector for connecting a breathing circuit to a patient interface described above may also comprise a heating element to heat the connector to disinfect the connection point between the circuit and the patient interface. 
     In some configurations a disinfection cycle (for example by disinfectant flush, radiation and/or heat as described above) may be automatically initiated or manually initiated. For example, a disinfecting cycle may be initiated automatically by disconnecting a patient interface from the breathing circuit. Alternatively a disinfection cycle could be activated on a timer sequence. 
     In some embodiments antimicrobial additives may be provided in the breathing circuit. For example, some possible additives include silver and silver based additives (colloidal silver, silver salts, silver zeolite, nano silver), siloxane based additives, Triclosan, and copper. Additives may be added to a breathing circuit by, for example a collar around an end or connection point of a breathing circuit where a patient interface is attached. The collar may be manufactured from an antimicrobial plastic. In some embodiments an entire breathing circuit may be made with antimicrobial additives, for example a breathing tube or conduit may be made from an antimicrobial plastic. Antimicrobial additives may be integrated into a conduit as an additive in the polymer that is used to make the conduit. In some embodiments, a release of antimicrobial additives may be activated by running water, or another disinfectant or applying heat or humidity or applying UV to a conduit comprising the additives. The disinfecting methods described above may be e used to release the antimicrobial additives in the conduit. 
     In some embodiments a cap  1025  may be provided to cover an end of the breathing circuit, as illustrated in  FIGS.  26 A and  26 B . A cap may be provided at a connection point between a patient interface tube  1017  and a breathing circuit  10101 , for example as shown in  FIG.  26 A . In some embodiments, a cap  1025  may be provided between a patient interface  10200  and a breathing circuit at a connection point adjacent to the patient interface, for example as illustrated in  FIG.  26 B . In some embodiments the cap  1025  is a separate piece of equipment that a user places on the end of a circuit when the patient interface is removed. In some embodiments the cap  1025  may be attached to the end of the breathing circuit, for example by a cord. In some embodiments a cap is built into the breathing circuit and is activated by a signal, for example an electrical, mechanical or magnetic signal, when the patient interface is removed or unplugged from the breathing circuit. In some embodiments, a pressure relief system or stop flow system may be included. For example, the cap  1025  may comprises a pressure release mechanism such as a relief valve to relieve excess pressure when the cap is fitted and in an instance when gases or pressure source continues to pressurize the breathing circuit. 
     In this way contamination cannot enter or is prevented from entering the breathing circuit when the interface is not attached (i.e., when the interface is changed between patients). As the flow travels in one direction (or predominately flows in one direction) contamination from the interface cannot enter or is prevented from entering the circuit when in use. 
     The cap can optionally also be made of a filter material or may comprise a one-way valve. In this way, additional protection from contamination can be provided. For example, this may find particular application in the case when the flow of gas is turned off to a patient interface, but the interface remains on a patient; condensate or contamination from the patient may be able to travel up the circuit if there is no cap or filter. 
     Alternatively, the gas supply may be triggered by the connection/disconnection of the interface (i.e., the flow always turns on or remains on, at least at a low level, when the interface is connected and turns off as soon as the interface is disconnected from the source of gas). 
     In some embodiments the breathing circuit may comprise an orifice to create a fast flow through the orifice to prevent infectious matter travelling back into the breathing circuit against the direction of flow through the orifice. This is related to the Peclet number, the ratio of the rate of advection to the rate of diffusion. If the Peclet number is greater than 1, advection dominates over diffusion and it would be unlikely infectious matter could diffuse into the breathing tube past the orifice. Ideally the higher the Peclet number (100, 1000 etc.), the less likely diffusion would influence the infectious matter and the less likely it would be to travel into the breathing circuit beyond the orifice. 
     In some embodiments, a one way valve system may be provided that only allows single direction flow from the breathing circuit to the patient interface. The one-way valve allows a flow of breathing gases to pass from the breathing circuit to the patient interface and the patient, but prevents flow from the patient interface back into the breathing circuit. The one-way valve prevents or reduces infectious matter entering the breathing circuit from the patient interface. The patient interface may be discarded after use, and the breathing circuit subsequently used by another patient. 
     In some embodiments a valve may be provided at a connection point between a patient interface and a respiratory breathing circuit. For example, in some embodiments a valve may be provided as a component to be inserted into an end of a conduit forming part of a respiratory breathing circuit, or in some embodiments, a valve may be provided as a component to be inserted into a patient interface to be connected to a breathing circuit. 
     In some embodiments, the valve may be provided within a connector for connecting a patient interface to a breathing circuit. In some embodiments, a valve may be provided as a separate element to be inserted into or attached to a conduit and/or patient interface. 
     In some embodiments, the valve may be a duckbill valve  1031  as shown in  FIG.  27 A , an umbrella valve  1032  as shown in  FIG.  27 B , a check ball valve  1033  as shown in  FIG.  27 C , or a constant velocity valve. 
     In some embodiments a valve may be inspiratory triggered. This means the flow is only delivered during inspiration when the pressure allows the valve to open. During expiration the valve closes and no flow is allowed to pass back into the breathing circuit. 
     In some embodiments the breathing circuit may include a pressure relief system to ensure the breathing circuit is not over pressurized. 
     In some embodiments a flow source providing a flow of respiratory gases to the breathing circuit, or other hardware of a respiratory breathing system upstream of the breathing circuit, comprises a switch that allows the flow to be turned ON (e.g. to 70 L/min or some other high flow rate or pressure associated with a high flow rate) and OFF (e.g. to 10 L/min or some other low flow rate or pressure associated with a low flow rate). 
     When the system is in OFF, there is still a low flow from the flow source to the patient interface and therefore reverse flow and transfer of infectious matter back into the breathing circuit is not possible. For example, in some embodiments, an item of equipment upstream of the breathing circuit such as a flow source includes an electrical connection that allows/starts the OFF flow when the flow source is connected to the breathing circuit and allows/starts the ON flow when the breathing circuit is connected to the patient interface. In some embodiments, an item of equipment upstream of the breathing circuit such as a flow source includes a mechanical switch (e.g. push valve) that allows different sized orifice openings to be introduced to the flow path to control the flow. 
     In some embodiments a mesh of hydrophobic material may be provided at a connection point between a patient interface and a respiratory breathing circuit. For example, in some embodiments a mesh may be provided at an end of a conduit forming part of a respiratory breathing circuit, or in some embodiments, a mesh may be provided at a patient interface to be connected to a breathing circuit. The mesh of hydrophobic material may have a pore size that is determined to ensure there is enough supply pressure at 70 L/min (or some other target high flow) to get the flow to pass through the pores of the mesh from the breathing circuit to the patient interface, but the pressure of exhalation from the patient is too small for the exhaled breath to go back through the mesh from the patient interface to the breathing circuit. 
     Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of “including, but not limited to.” 
     It is intended that reference to a range of numbers disclosed herein (for example, 1 to 10) also incorporates reference to all rational numbers within that range (for example, 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9 and 10) and also any range of rational numbers within that range (for example, 2 to 8, 1.5 to 5.5 and 3.1 to 4.7) and, therefore, all sub-ranges of all ranges expressly disclosed herein are hereby expressly disclosed. These are only examples of what is specifically intended and all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be expressly stated in this application in a similar manner. 
     As used herein the term “(s)” following a noun means the plural and/or singular form of that noun. 
     As used herein the term “and/or” means “and” or “or”, or where the context allows both. 
     Where the terminology “configured to” is used herein, that terminology could alternatively be replaced with “arranged to” or “adapted to”. 
     Where, in the foregoing description reference has been made to integers or components having known equivalents thereof, those integers are herein incorporated as if individually set forth. 
     The disclosure may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features. 
     Reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general knowledge in the field of endeavour in any country in the world. 
     Certain features, aspects and advantages of some configurations of the present disclosure have been described with reference to use of the gas humidification system with a respiratory therapy system. However, certain features, aspects and advantages of the use of the gas humidification system as described may be advantageously be used with other therapeutic or non-therapeutic systems requiring the humidification of gases. Certain features, aspects and advantages of the methods and apparatus of the present disclosure may be equally applied to usage with other systems. 
     Although the present disclosure has been described in terms of certain embodiments, other embodiments apparent to those of ordinary skill in the art also are within the scope of this disclosure. Thus, various changes and modifications may be made without departing from the spirit and scope of the disclosure. For instance, various components may be repositioned as desired. Features from any of the configurations describe above may be combined with each other and/or a respiratory support system or humidifier may comprise one or more of the above described configurations. Moreover, not all of the features, aspects and advantages are necessarily required to practice the present disclosure. Accordingly, the scope of the present disclosure is intended to be defined only by the claims that follow.