EP4791470A1

EP4791470A1 - Oral interface for providing respiratory support

Info

Publication number: EP4791470A1
Application number: EP24876801.2A
Authority: EP
Inventors: Matthew Jon Payton; Rachael GLAVES; Cameron Leslie MATTHEWS; Thomas Heinrich Barnes
Original assignee: Fisher and Paykel Healthcare Ltd
Current assignee: Fisher and Paykel Healthcare Ltd
Priority date: 2023-10-13
Filing date: 2024-10-11
Publication date: 2026-08-19
Also published as: WO2025079004A1; CN122396518A; AU2024358799A1

Abstract

An oral interface for providing respiratory support to a patient, comprises at least one gases inlet for receiving a gases flow; at least one gases outlet for providing the gases flow to the patient; a gases flow path defined between the at least one gases inlet and the at least one gases outlet; and a body. The body comprises a mouth-engaging portion configured to engage with a mouth of the patient; a first end opening and a second end opening disposed on opposite sides of the body. The first end opening and the second end opening define a channel for providing access into the mouth. The at least one gases outlet comprises a restriction configured to increase an average velocity of the gases flow upon exiting the at least one gases outlet.

Description

ORAL INTERFACE FOR PROVIDING RESPIRATORY SUPPORT Cross reference to related application [0001] This application claims priority from United States provisional patent application No. 63/590,144 filed on 13 October 2023, the contents of which are to be taken as incorporated herein by this reference. Technical Field [0002] The present disclosure relates to a patient interface for use in a system that provides respiratory support to a patient. More specifically, embodiments of the present disclosure relate to an oral interface for providing respiratory support to patients and a system including such an oral interface. Background [0003] Respiratory support may be provided to a patient in several settings including but not limited to intensive care units, hospital wards or in the operating theatre. Respiratory support may need to be provided for a patient undergoing certain medical procedures. For example, surgical procedures may require the patient to be anesthetised, or sedated. In anaesthetic procedures, respiratory support such as high flow respiratory support delivered nasally may be provided to a patient via a nasal cannula throughout the procedure but especially during preoxygenation, intubation, and/or extubation. [0004] Some medical procedures do not require the mouth to be closed whilst some require the mouth to be open for access into the airways of the patient. However, when the mouth is open to atmosphere, the pressure in the airways reduces (even when high flow respiratory support is delivered nasally) and the risk of airway collapse and/or atelectasis increases. [0005] It would be desirable to provide an oral interface that reduces the risks encountered during procedures that involve a patient’s mouth being open. Thus, an oral interface capable of improving or maintaining airway pressure when the patient’s mouth is open is desirable. [0006] The discussion of the background to the invention included herein including reference to documents, acts, materials, devices, articles and the like is included to explain the context of the present invention. This is not to be taken as an admission or a suggestion that any of the material referred to was published, known or part of the common general knowledge. Summary of the Invention [0007] According to an aspect of the present disclosure, there is provided an oral interface for providing respiratory support to a patient, the oral interface comprising: at least one gases inlet for receiving a gases flow; at least one gases outlet for providing the gases flow to the patient; a gases flow path defined between the at least one gases inlet and the at least one gases outlet; and a body comprising: a mouth-engaging portion configured to engage with a mouth of the patient; a first end opening and a second end opening disposed on opposite sides of the body, the first end opening and the second end opening defining a channel for providing access into the mouth; wherein the at least one gases outlet comprises a restriction configured to increase an average velocity of the gases flow upon exiting the at least one gases outlet. [0008] The at least one gases outlet may be disposed at any one of: at or proximal to the first end opening, between the first end opening and the second end opening, or at or proximal to the second end opening. The channel extends between the first end opening and the second end opening. [0009] The restriction may be a nozzle configured to generate a jet flow of the gases flow. In some examples, the restriction my be provided in the gases flow path upstream of the at least one gases outlet. [0010] At least part of the gases flow path may extend e.g. circumferentially around the channel. At least part of the gases flow path may be defined by structural features of the body. In some examples, at least part of the gases flow path may be defined between outer and inner wall portions of the body. In some examples, the mouth engaging portion may comprise an outer wall portion of the body. In some examples, at least part of the gases flow path may be arranged concentrically with the channel, so that the gases flow path at least partially surrounds the channel. The gases flow path may surround part or all of length of the channel extending longitudinally between the first end opening and the second end opening. The gases flow path may be arranged external to the channel. In some examples, the one or more gases outlets may be arranged such that the gases flow exiting the gases flow path through one or more gases outlets is provided to the patient through the channel, when in use. [0011] The at least one gases outlet may be disposed along a perimeter of the channel. The channel may have an elliptical, obround, circle, oval or other cross sectional shape. [0012] In some embodiments, the average velocity of the gases flow may be substantially uniform around the channel. [0013] A width of the at least one gases outlet may be substantially uniform around the channel. [0014] The at least one gases outlet may be configured to direct the gases flow in a direction substantially parallel to an axis of the body extending between the first end opening and the second end opening. [0015] In some embodiments, the at least one gases outlet may be configured to direct the gases flow to converge from the first end opening towards the second end opening based on one or both of an angle of the restriction and a cross-sectional width of the gases flow path. [0016] In some embodiments, the at least one gases outlet may be configured to direct the gases flow to converge towards a line proximal to the second end opening. The line may be substantially orthogonal to the axis of the body extending between the first end opening and the second end opening. [0017] In some embodiments, the at least one gases outlet may be configured to direct the gases flow to converge towards a point proximal to the second end opening. A location of the point may be determined according to one or more of an angle of the at least one gases outlet, shape of the at least one gases outlet, a cross-sectional width of the gases flow path, shape of the at least one gases inlet, and average velocity of the gases flow. [0018] The at least one gases outlet may further be configured to provide the gases flow such that airway pressure of the patient is at least about 0.1 cmH2O or about 0.2 cmH2O, or about 0.3 cmH2O, or about 0.4 cmH2O, or about 0.5 cmH2O, or about 0.6 cmH2O, or about 0.7 cmH2O, or about 0.8 cmH2O, or about 0.9 cmH2O, or about 1 cmH2O, or about 2 cmH2O, or about 3 cmH2O, or about 4 cmH2O, or about 5 cmH2O, or about 6 cmH2O, or about 7 cmH2O, or about 8 cmH2O, or about 9 cmH2O or about 10 cmH2O. [0019] In some embodiments, the at least one gases outlet may be configured to provide the gases flow such that airway pressure of the patient is between about 0.1 cmH2O and about 10 cmH2O or about 0.2 cmH2O to about 7 cmH2O, or about 2 cmH2O to about 7 cmH2O, or about 2 cmH2O to 10cmH2O. [0020] The gases flow may have a flow rate of between about 0LPM and about 200LPM. In some embodiments, the gases flow may have a rate of between about 20LPM and about 200LPM. [0021] The average velocity of the gases flow may be about 100m/sec. [0022] The body of the oral interface may have a cross-section with a first dimension and a second dimension perpendicular to the first dimension, wherein the first dimension is greater than the second dimension. [0023] In some embodiments, at least part of the body may have an elliptical obround, circle, oval or other cross-section transverse to an axis extending from the first end opening to the second end opening. [0024] A cross-sectional width of the gases flow path may be non-uniform around the channel. A width of the at least one gases outlet may be non-uniform around the channel. [0025] The at least one gases outlet may comprise two or more gases outlets disposed around the channel. [0026] The at least one gases inlet may comprise a first gases inlet and a second gases inlet. The first gases inlet may have a cross-sectional area substantially equal to a cross- sectional area of the second gases inlet. [0027] Further, in some embodiments, one of the first gases inlet and the second gases inlet may be disposed to be proximal to a nose of the patient when in use. [0028] In some embodiments, the first gases inlet and the second gases inlet may be disposed opposite to each other. [0029] The oral interface may comprise a cover disposed around the mouth-engaging portion of the body. In some embodiments, the cover may be disposed around a section of the mouth-engaging portion that is configured to be inside the mouth of the patient and configured to provide a substantial seal around the oral interface and the mouth of the patient such that fluid access to the mouth of the patient is substantially via the channel. [0030] The oral interface may further comprise headgear connectors configured to removably connect with a headgear wearable by the patient to stabilize the oral interface during use. [0031] According to another aspect of the present disclosure, there is provided an oral interface for providing respiratory support to a the oral interface comprising: at least one gases inlet for receiving a gases flow; at least one gases outlet for providing the gases flow towards the back of a mouth of the patient; a gases flow path defined between the at least one gases inlet and the at least one gases outlet; and a body comprising: a first end opening and a second end opening disposed on opposite sides of the body, the first end opening and the second end opening defining a channel for providing access into a mouth of the patient, wherein the at least one gases outlet is disposed circumferentially around the channel and configured to provide the gases flow as a jet flow towards the back of the mouth of the patient. [0032] In some embodiments, the at least one gases outlet may be disposed at any one of the following locations: at or proximal the first end opening, between the first end opening and the second end opening, or at or proximal the second end opening. [0033] The at least one gases outlet may be configured to provide the gases flow as the jet flow into the channel. [0034] The at least one gases outlet may comprise a nozzle configured to provide the jet flow. [0035] The at least one gases outlet may be disposed along a perimeter of the channel. [0036] The at least one gases outlet may comprise a circumferential slit provided around the perimeter of the body defining the gases flow path. [0037] In some embodiments, the at least one gases outlet may be configured to direct the gases flow in a direction substantially parallel to an axis of the body extending between the first end opening and the second end opening. [0038] In some embodiments, the at least one gases outlet may be configured to direct the gases flow to converge from the first opening towards the second end opening based on one or more of an angle of the restriction, an angle of the at least one gas outlet, shape of the at least one gas outlet and a cross-sectional width of the gases flow path. [0039] In some embodiments, the at least one gases outlet may be configured to direct the gases flow to converge towards a line proximal to the second end opening. The line may be substantially orthogonal to the axis of the body extending between the first end opening and the second end opening. [0040] In some embodiments, the at least one gases outlet may be configured to direct the gases flow to converge towards a point proximal the second end opening. Location of the point may be based on one or more of an angle of the restriction, an angle of the at least one gases outlet, shape of the at least one gases outlet, a cross-sectional width of the gases flow path, shape of the at least one gases inlet, average velocity of the gases flow. [0041] In some embodiments, the at least one gases outlet may be configured to direct the gases flow towards the second end opening. [0042] The average velocity of the gases flow proximal to the at least one gases outlet may be substantially uniform around the channel. [0043] In some embodiments, the at least one gases outlet may be configured to provide the gases flow such that airway pressure of the patient is at least about 0.1 cmH2O or about 0.2 cmH2O, or about 0.3 cmH2O, or about 0.4 cmH2O, or about 0.5 cmH2O, or about 0.6 cmH2O, or about 0.7 cmH2O, or about 0.8 cmH2O, or about 0.9 cmH2O, or about 1 cmH2O, or about 2 cmH2O, or about 3 cmH2O, or about 4 cmH2O, or about 5 cmH2O, or about 6 cmH2O, or about 7 cmH2O, or about 8 cmH2O, or about 9 cmH2O or about 10 cmH2O. [0044] In some embodiments, the at least one gases outlet may be configured to provide the gases flow such that airway pressure of the patient is between about 0.1 cmH2O and about 10 cmH2O or about 0.2 cmH2O to about 7 cmH2O, or about 2 cmH2O to about 7 cmH2O, or about 2 cmH2O to 10cmH2O. [0045] The gases flow may have a flow rate of e.g. between about 0 LPM and about 200 LPM. For example, the gases flow may have a flow rate of between about 20 LPM and about 200 LPM. [0046] The average velocity of the gases flow may be about 100 m/sec. [0047] In some embodiments, the body may have a cross-section with a first dimension and a second dimension perpendicular to the first dimension, wherein the first dimension is greater than the second dimension. [0048] In some embodiments, at least part of the body may have an elliptical, obround, circle, oval or other cross-sectional shape transverse to an axis extending from the first end opening to the second end opening. [0049] In some embodiments, a cross-sectional width of the gases flow path may be non- uniform around the channel. [0050] In some embodiments, the at least one gases outlet may comprise two or more gases outlets disposed around the channel. [0051] In some embodiments, the at least one gases inlet may comprise a first gases inlet and a second gases inlet. [0052] In some embodiments, first gases inlet may have a cross-sectional area substantially equal to a cross-sectional area of the second gases inlet. [0053] In some embodiments, one of the first gases inlet and the second gases inlet may be disposed to be proximal to a nose of the patient when in use. [0054] In some embodiments, the first gases inlet and the second gases inlet may be disposed opposite to each other. [0055] The oral interface may comprise a cover disposed around the body. In some embodiments, the cover may be disposed around a section of the body that is configured to be inside the mouth of the patient and further configured to provide a substantial seal between the mouth-engaging portion and the teeth and/or lips of the patient e.g. such that fluid access to the mouth of the patient is substantially via the channel. [0056] In some embodiments, the oral interface comprises one or more headgear connectors configured to removably connect with a headgear wearable by the patient to stabilize the oral interface during use. [0057] According to another aspect, there is provided an oral interface for providing respiratory support to a patient, the oral interface comprising: at least one gases inlet for receiving a gases flow; at least one gases outlet for providing the gases flow to the patient; a gases flow path between the at least one gases inlet and the at least one gases outlet; and a body comprising: a mouth-engaging portion configured to engage with a mouth of the patient; a first end opening and a second end opening disposed on opposite sides of the body, the first end opening and the second end opening defining a channel for providing access into the mouth; wherein the gases flow path comprises a restriction configured to increase an average velocity of the gases flow upon exiting the at least one gases outlet. [0058] According to a further aspect of the present disclosure, there is provided an oral interface for providing respiratory support to a the oral interface comprising: at least one gases inlet for receiving a gases flow; at least one gases outlet for providing the gases flow to the patient; a gases flow path defined between the at least one gases inlet and the at least one gases outlet; and a body comprising: a first end opening and a second end opening disposed on opposite sides of the body, the first end opening and the second end opening defining a channel for providing access into a mouth of the patient; wherein the at least one gases outlet is configured such that an average velocity of the gases flow exiting the at least one gases outlet is up to about 110m/s. [0059] In some embodiments, the average velocity of the gases flow exiting the at least one gases outlet may be between about 10m/s and about 110m/s. [0060] In some embodiments, the average velocity of the gases flow exiting the at least one gases outlet may be between about 40m/s and about 110m/s. [0061] In some embodiments, the average velocity of the gases flow may be about 100m/sec. [0062] In some embodiments, the gases flow path may be extend e.g. circumferentially around at least part of the channel. [0063] In some embodiments, the at least one gases outlet may be disposed around a perimeter of the channel. The channel may have an elliptical, obround, circle, oval or other cross sectional shape. Therefore, the at least one gases outlet may be disposed e.g. circumferentially around the channel although that need not be the case and the at least one gases outlet may be disposed in e.g. a spiral or other arrangement around a perimeter (or boundary) of the channel. [0064] In some embodiments, the average velocity of the gases flow may be substantially uniform around the channel. [0065] In some embodiments, a width of the at least one gases outlet may be substantially uniform around the channel. [0066] In some embodiments, the at least one gases outlet may be configured to direct the gases flow in a direction substantially parallel to an axis of the body extending between the first end opening and the second end opening. [0067] In some embodiments, the at least one gases outlet may be configured to direct the gases flow to converge from the first end opening the second end opening based on one or both of an angle of the restriction and a cross-sectional width of the gases flow path. [0068] In some embodiments, the at least one gases outlet may be configured to direct the gases flow to converge towards a line proximal to the second end opening. The line may be substantially orthogonal to the axis of the body extending between the first end opening and the second end opening. [0069] In some embodiments, the at least one gases outlet is configured to direct the gases flow to converge towards a point proximal to the second end opening. The location of the point inside the channel may be based on one or more of an angle of the restriction, an angle of the at least one gas outlet, shape of the at least one gas outlet, a cross-sectional width of the gases flow path, shape of the at least one gases inlet, average velocity of the gases flow. [0070] In some embodiments, the at least one gases outlet may be configured to provide the gases flow such that airway pressure of the patient is at least about 0.1 cmH2O or about 0.2 cmH2O, or about 0.3 cmH2O, or about 0.4 cmH2O, or about 0.5 cmH2O, or about 0.6 cmH2O, or about 0.7 cmH2O, or about 0.8 cmH2O, or about 0.9 cmH2O, or about 1 cmH2O, or about 2 cmH2O, or about 3 cmH2O, or about 4 cmH2O, or about 5 cmH2O, or about 6 cmH2O, or about 7 cmH2O, or about 8 cmH2O, or about 9 cmH2O or about 10 cmH2O. [0071] In some embodiments, the at least one gases outlet may be configured to provide the gases flow such that airway pressure of the patient is between about 0.1 cmH2O and about 10 cmH2O or about 0.2 cmH2O to about 7 cmH2O, or about 2 cmH2O to about 7 cmH2O, or about 2 cmH2O to 10cmH2O. [0072] In some embodiments, the gases flow may have a flow rate of between about 0LPM and about 200LPM. For example, the gases flow may have a flow rate of between about 20LPM and about 200LPM. [0073] In some embodiments, the body may have a cross-section with a first dimension and a second dimension perpendicular to the first dimension, wherein the first dimension is greater than the second dimension. [0074] In some embodiments, at least part of the body may have an elliptical or obround, circle, oval or other cross-sectional shape transverse to an axis extending from the first end opening to the second end opening. [0075] In some embodiments, a cross-sectional width of the gases flow path may be non- uniform around the channel. A width of the at gases outlet may be non-uniform around the channel. [0076] In some embodiments, the at least one gases outlet may comprise two or more gases outlets disposed around the channel. [0077] In some embodiments, the at least one gases inlet may comprise a first gases inlet and a second gases inlet. [0078] In some embodiments, the first gases inlet may have a cross-sectional area substantially equal to a cross-sectional area of the second gases inlet. [0079] In some embodiments, one of the first gases inlet or the second gases inlet may be disposed to be proximal to a nose of the patient when in use. [0080] In some embodiments, the first gases inlet and the second gases inlet may be disposed opposite to each other. [0081] According to yet another aspect of the present disclosure, there is provided a patient interface assembly comprising: a nasal interface; and an oral interface according to any one of the previous aspects. [0082] In some embodiments, the nasal interface and the oral interface may be configured to receive the gases flow from a common flow source. [0083] In other embodiments, the nasal interface and the oral interface may be configured to receive the gases flow from separate flow sources. [0084] The nasal interface may provide a first gases flow to the patient at a first flow rate and the oral interface may provide a second gases flow to the patient at a second flow rate. [0085] In some embodiments, the first flow rate may be different to the second flow rate. [0086] In some embodiments, the first flow rate and the second flow rate may be between about 0 LPM and about 100 LPM. [0087] For example, the first flow rate and the second flow rate may be between about 20 LPM and about 100 LPM. [0088] In some embodiments, a sum of the first flow rate and the second flow may be between about 0 LPM and about 200 LPM. [0089] The nasal interface and the oral interface may be fluidly connected. [0090] A base of the nasal interface may comprise an interface connector to allow fluid communication with the gases flow path in the oral interface. [0091] The nasal interface may comprise a nasal cannula. In some embodiments, the nasal cannula may be non-sealing. [0092] In some embodiments, the nasal interface may create a seal with the patient’s nares. The sealing nasal interface may comprise a nasal cannula, nasal mask or nasal pillows. The sealing interface may comprise a nasal clip. [0093] According to yet further aspect of the present disclosure, there is provided a system for providing respiratory support to a patient, the system comprising: at least one flow source for generating a gases flow; at least one humidifier configured to humidify the gases flow for delivery of a humidified gases flow to a patient interface; and the patient interface assembly according to the previous aspect. [0094] According to a further aspect of the present disclosure, there is provided a system for providing respiratory support to a patient, the system comprising: at least one flow source for generating a gases flow; and the patient interface assembly according to the above aspect. [0095] It is to be understood each of the various aspects described herein may incorporate one or more features, modifications and alternatives described in the context of one or more other aspects and may include one or more features, modifications and alternatives of any of the embodiments described below, as appropriate. For efficiency, such features, modifications and alternatives have not been repetitiously disclosed for each and every aspect although one of skill in the art will appreciate that such combinations of features, modifications and alternatives disclosed for some aspects and embodiments apply similarly for other aspects and are within the scope of and form part of the subject matter of this disclosure. Brief Description of Drawings [0096] Embodiments of the disclosure will be described by way of example only and with reference to the drawings, in which: [0097] Figure 1 illustrates a system for providing high flow respiratory support according to one embodiment of the disclosure; [0098] Figure 2a illustrates a cross-sectional side view of an oral interface for use with the system of Figure 1 according to one embodiment of the disclosure; Figure 2b is a first enlarged portion of Figure 2a; Figure 2c is a second enlarged portion of Figure 2a; [0099] Figure 3 illustrates a cross-sectional side view of an oral interface for use with the system of Figure 1 according to another embodiment of the disclosure; [0100] Figure 4 illustrates a perspective side view of an oral interface; [0101] Figure 5 illustrates the oral interface of Figure 4 from a front view (that faces away from the patient in use); [0102] Figure 6 illustrates the oral interface of Figures 4 and 5 from a back view (that faces towards the patient in use); [0103] Figure 7 illustrates the oral interface of Figures 4 to 6 from a top view; [0104] Figure 8 illustrates the oral interface with a single gases inlet according to an embodiment of the disclosure; [0105] Figure 9 illustrates oral interface with two gases inlets according to an embodiment of the disclosure; [0106] Figures 10 to 12 illustrate various orientations of the at least one gases inlet of the oral interface according to various embodiments of the disclosure; [0107] Figure 13 illustrates a nozzle of the oral interface oriented at about 0 degrees to a longitudinal axis of the oral interface according to an embodiment of the disclosure; [0108] Figure 14 illustrates a flow pattern of gases flow exiting the nozzle of the oral interface of Figure 13; [0109] Figure 15 illustrates a nozzle of the oral interface oriented at about 45 degrees to a longitudinal axis of the oral interface according to an embodiment of the disclosure; [0110] Figure 16 illustrates a flow pattern of gases flow exiting the nozzle of the oral interface of Figure 15; [0111] Figures 17 illustrates a nozzle of the oral interface oriented at about 90 degrees according to an embodiment of the disclosure; [0112] Figure 18 illustrates a flow pattern of gases flow exiting the nozzle of the oral interface of Figure 17; [0113] Figures 19 to 21 are sectional perspective views illustrating different profiles of convergence of flow of the gases inside the oral interface when the nozzle is oriented at an angle of about 45 degrees to an axis of the oral interface when having non-circular e.g. obround shape according to various embodiments of the disclosure; [0114] Figure 22 is a side sectional view illustrating a flow profile of gas inside the oral interface, when the nozzle is oriented at an angle of about 45 degrees to an axis of the oral interface which has a circular shape according to an embodiment of the disclosure; [0115] Figure 23 illustrates a patient interface assembly including the oral interface and a nasal interface according to one embodiment of the disclosure; [0116] Figure 24 illustrates the gases flow from a common flow source into the oral interface and the nasal interface of Figure 23; [0117] Figure 25 illustrates the nasal interface fluidly connected to the oral interface at the base of the nasal interface according to one embodiment of the disclosure; [0118] Figure 26 illustrates the gases flow when the nasal interface is fluidly connected to the oral interface at the base of the nasal interface as in Figure 25; [0119] Figure 27 illustrates an alternate embodiment including the nasal interface and the oral interface connected via an interface connector; [0120] Figure 28 illustrates a patient interface assembly including the oral interface 20 and a nasal interface, each receiving gases flow from separate flow sources according to an embodiment of the disclosure; [0121] Figure 29 shows a patient wearing a patient assembly having an oral interface and a nasal interface, and a face mask applied over the top of the patient assembly; [0122] Figure 30 shows a cross-section of a substantially collapsible portion of a patient interface or conduit in substantially open and substantially collapsed conditions respectively; [0123] Figure 31 illustrates a patient interface assembly corresponding to Figure 23, with a collapsible portion in the conduits supplying gas the common flow source to each of the nasal interface and the oral interface; [0124] Figure 32 illustrates a patient interface assembly corresponding to Figure 26, with a collapsible portion in the conduit supplying gas from a common flow source to the nasal interface which subsequently flows to the oral interface; [0125] Figure 33 illustrates a patient interface assembly corresponding to Figure 27, with a collapsible portion in the conduit supplying gas from a common flow source to the oral interface which subsequently flows to the nasal interface; and [0126] Figure 34 illustrates a patient interface assembly corresponding to Figure 28, with a collapsible portion in the conduits supplying gas from separate flow sources to each of the oral interface and the nasal interface gases flow when the nasal. Detailed Description [0127] Throughout the figures and specification, similar reference numerals may be used to designate the same or similar components, and redundant descriptions thereof may be omitted. [0128] As mentioned, respiratory systems provide gas or gases for delivery to a patient. Respiratory systems may take a number of forms, such as positive airway pressure systems (PAP) and high flow respiratory gas systems (e.g., for use in high flow therapy employed in respiratory support and anaesthesia procedures). [0129] In this specification, “high flow” means, without limitation, any gas flow with a flow rate that is higher than usual/normal, such as higher than the normal inspiration flow rate of a healthy patient. It can be provided by a non-sealing respiratory system with uncontrolled and often substantial leak happening at the entrance of the patient’s airways due to a non-sealing patient interface, for example non-sealing prongs. It can be also provided with humidification to improve patient comfort, compliance and safety. Alternatively, or additionally, it can be higher than some other threshold flow rate that is relevant to the context. For example, where providing a gas flow to a patient at a flow rate to meet inspiratory demand (e.g. instantaneous inspiratory demand or peak inspiratory demand. This could be the inspiratory demand of the patient that is receiving the respiratory support, or a representative inspiratory demand, such as representative of patients based on e.g. empirical data). That flow rate might be deemed “high flow” as it is higher than a nominal flow rate that might have otherwise been provided. “High flow” is therefore context dependent, and what constitutes “high flow” depends on many factors such as the health state of the patient, type of being provided, the nature of the patient (big, small, adult, child) and the like. Those skilled in the art would appreciate from context what constitutes “high flow”. It is a magnitude of flow rate that is over and above a flow rate that might otherwise be provided. [0130] But, without limitation, some indicative values of high flow can be as follows. [0131] In some configurations, delivery of gases to a patient may be at a flow rate of greater than or equal to about 5 or 10 litres per minute (5 or 10 LPM or L/min). [0132] In some configurations, provision of gases to a patient may be at a flow rate of about 5 or 10 LPM to about 150 LPM, or about 15 LPM to about 95 LPM, or about 20 LPM to about 90 LPM, or about 25 LPM to about 85 LPM, or about 30 LPM to about 80 LPM, or about 35 LPM to about 75 LPM, or about 40 LPM to about 70 LPM, or about 45 LPM to about 65 LPM, or about 50 LPM to about 60 LPM. For example, according to various embodiments and configurations described herein, a flow rate of gases supplied or provided to an interface via a system or from a flow source or flow modulator, 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 LPM, or more, and useful ranges may be selected to be any of these values (for example, about 20 LPM to about 90 LPM, about 40 LPM to about 70 LPM, about 40 LPM to about 80 LPM, about 50 LPM to about 80 LPM, about 60 LPM to about 80 LPM, about 70 LPM to about 100 LPM, about 70 LPM to about 80 LPM). [0133] In “high flow” the gas or gases delivered will be chosen depending on for example the intended use of a therapy. Gases delivered may comprise a percentage of oxygen. In some configurations, the percentage of oxygen in the gases delivered may be about 15% to about 100%, 20% to about 100%, or about 30% to about 100%, or about 40% to about 100%, or about 50% to about 100%, or about 60% to about 100%, or about 70% to about 100%, or about 80% to about 100%, or about 90% to about 100%, or about 100%, or 100%. [0134] In some embodiments, gases delivered may comprise a percentage of carbon dioxide. In some configurations, the percentage of carbon dioxide in the gases delivered may be more than 0%, about 0.3% to about 100%, about 1% to about 100%, about 5% to about 100%, about 10% to about 100%, about 20% to about 100%, or about 30% to about 100%, or about 40% to about 100%, or about 50% to about 100%, or about 60% to about 100%, or about 70% to about 100%, or about 80% to about 100%, or about 90% to about 100%, or about 100%, or 100%. [0135] In some embodiments, the at least one gases outlet is configured to provide a gases flow such that the airway pressure of the patient airway is at least about 0.1 cmH2O, or about 0.2 cmH2O, or about 0.3 cmH2O, or about 0.4 cmH2O, or about 0.5 cmH2O, or about 0.6 cmH2O, or about 0.7 cmH2O, or about 0.8 cmH2O, or about 0.9 cmH2O, or about 1 cmH2O, or about 2 cmH2O, or about 3 cmH2O, or about 4 cmH2O, or about 5 cmH2O, or about 6 cmH2O, or about 7 cmH2O, or about 8 cmH2O, or about 9 cmH2O or about 10 cmH2O. In some embodiments, the at least one gases outlet is configured to provide a gases flow such that the airway pressure of the patient is at least about 0.1 cmH2O to about 10 cmH2O or about 0.2 cmH2O to about 7 cmH2O, or about 2 cmH2O to about 7 cmH2O, or about 2 cmH2O to 10cmH2O. [0136] Flow rates for “high flow” for premature/infants/paediatrics (with body mass in the range of about 1 to about 30 kg) can be different. The flow rate can be set to 0.4 to 8 L/min/kg with a minimum of about 0.5 L/min and a maximum of about 70 L/min. For patients under 2 kg maximum flow may be set to 8 L/min. [0137] High flow has been found effective in meeting or exceeding the patient’s normal inspiratory flow, 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 for each and every breath, while minimising re- breathing of carbon dioxide, nitrogen, etc. [0138] By way of example, a system 10 for use in high flow respiratory support is described with reference to Figure 1. High flow respiratory therapy may be used as a means to promote gas exchange and/or respiratory support through the delivery of oxygen and/or other gases, and through the removal of CO2 from the patient’s airways. [0139] High flow respiratory therapy may be particularly useful prior to, during or after a medical and/or anaesthetic procedure. [0140] When used prior to a medical procedure, high flow respiratory support can pre-load the patient with oxygen so that their blood oxygen saturation level and volume of oxygen in the lungs is higher to provide an oxygen buffer while the patient is in an apnoeic phase during the medical procedure. [0141] A continuous supply of oxygen to the patient’s airway is important to sustain healthy respiratory function during medical procedures (such as during anaesthesia) where respiratory function might be compromised (e.g., diminishes or stops). When this supply is compromised, hypoxia, hypoxaemia, and/or hypercapnia can occur. During medical procedures such as anaesthesia and/or sedation where the patient is unconscious or may become unconscious, the patient is monitored to detect when this happens. If oxygen supply and/or CO2 removal is compromised, the clinician stops the medical procedure and facilitates oxygen supply and/or CO2 removal. This can be achieved by manually ventilating the patient for example by bag mask ventilation, or by providing a high flow of gases to the patient’s airway using a high flow respiratory system. [0142] Further advantages of high gas flow can include that the high gas flow increases pressure in the airways of the patient, thereby providing pressure support that opens airways, the trachea, lungs/alveolar and bronchioles. The opening of these structures can enhance oxygenation, and may, to some extent, assist in removal of CO2. [0143] When humidified, the high gas flow can also prevent airways from drying out, mitigating mucociliary damage, and reducing risk of laryngospasms and risks associated with airway drying such as nose bleeding, aspiration (as a result of nose bleeding), and airway obstruction, swelling and bleeding. Another advantage of high gas flow is that the flow can clear smoke created during surgery in the air passages. For example, smoke can be created by lasers and/or cauterizing devices. [0144] With reference to Figure 1, the system 10 may comprise an integrated or separate component-based arrangement, generally shown in the dotted box 11 in Figure 1. In some configurations, the system 10 could comprise a modular arrangement of components. The system 10 may include a flow source 12, such as an in-wall source of oxygen, an oxygen tank, a blower, a flow therapy apparatus, or any other source of oxygen, air or other gas or combination thereof. In some embodiments, the flow source 12 comprises a flow modulator and in some embodiments, the flow modulator comprises a flow generator such as a blower, bellow, and/or pistons. In some embodiments, the flow modulator comprises a flow generator and a proportional valve which may function to control oxygen concentration in a flow of blended gas such as air (preferably filtered air) and oxygen which is delivered to the patient. In some embodiments, the flow modulator comprises a proportional valve, and in such embodiments, the flow modulator may not comprise a flow generator. In other embodiments, the flow source 12 need not comprise a flow generator and in such the flow source 12 may comprise an in-wall gas source and/or a blended gas or other gas supply. In some embodiments, the flow source 12 may comprise a compressed gas source (e.g., an in- wall gas source, an oxygen tank supply, etc.) and a blower. In some embodiments, the flow source 12 may comprise a compressed gas source (e.g., an in- wall gas source, an oxygen tank supply, etc.) and a proportional valve or other flow valve to control the flow of gases from the compressed gas source. [0145] In some embodiments, the flow source 12 comprises or is part of an anaesthesia machine. The system 10 may also comprise an additive gas source 12A, comprising one or more other gases that can be combined with gases from the flow source 12. The flow source 12 can provide a gases flow 13 that can be delivered to a patient 16 via a delivery conduit 14, and patient interface assembly 15 (such as an oral interface as will be described in more detail below, for use with or without a nasal cannula). The patient depicted is an adult. However, the patient may be an infant, child or adolescent. The gases flow 13 may deliver a high flow to the patient, in the context described in the foregoing. A controller 19 controls the flow source 12 and additive gas source 12A through valves or the like to control flow and other characteristics such as any one or more of flow rate, pressure, composition, concentration and volume of the gases flow 13. A humidifier 17 is also optionally provided, which can humidify the gas and/or control the temperature of the gas, for example under the control of the controller 19. The humidifier 17 may be a separate component that may be provided in fluid communication with the flow source 12. One or more sensors 18a, 18b, 18c, 18d, such as flow, oxygen, pressure, humidity, temperature, Respiratory Inductance Plethysmography bands or other sensors can be placed throughout the system and/or at, on or near the patient 16. The sensors can include a pulse oximeter 18d on the patient for determining the oxygen concentration in the blood. [0146] The controller 19 may be operatively coupled with one or more components of system 10 by various means including wired or wireless coupling. For example, controller 19 may be operatively coupled with one or more of the flow source 12, the additive gas source 12A, humidifier 17 and sensors 18a-18d and input/output (I/O) interface 20. By way of example, the controller 19 may be provided on or in a high flow apparatus, a separate component and/or incorporated into or utilised with another device such as an anaesthesia machine or a ventilator, or it may comprise part of system 10 and communicate with one or more separate controllers controlling operation of separate components used with system 10 for the provision of respiratory support to the patient. The controller may comprise a microcontroller, a PID (proportional-integral-derivative) controller or a variation of a PID controller where the proportional, integral and derivative elements of can be turned on or off as needed (such as P, PI or I controllers), or some other architecture, configured to operate by an algorithm that is stored in a memory in communication with the controller to direct the operation of controllable components of the respiratory system. The controller 19 may thus control the flow source 12 and other components of or used with system 10 to provide the delivered flow of gas to the patient with certain characteristics such as a desired flow rate, pressure, composition (where more than one gas is being provided), volume and/or other parameters based on feedback from one or more sensors 18a-18d. The controller 19 can also control any other suitable parameters of the flow source to meet oxygenation, airway pressure and/or flow requirements of the patient and/or system pressure and/or flow requirements of the system (for example pre-determined or set by a user through interface 20). The controller 19 can also control the humidifier 17 and this control may be based on feedback from one or more of the sensors 18a-18d. Using input from the sensors, the controller may determine operational changes required to meet oxygenation requirements and alter control parameters of the flow source 12 and/or humidifier 17 and/or other additive gas source 12A and/or other components of the system as required. [0147] An input/output (I/O) interface 20 (such as a display and/or input device) may be provided. The interface 20 enables information and inputs (such as the required patient respiratory support parameters) to be received from a user (e.g. clinician or patient) that can be used for determining oxygenation, pressure, flow requirements and/or other system settings used in the control of one or more of the flow source 12, additive gas source 12A and other components of the system 10, to achieve a gases flow 13 with the characteristics necessary to provide the required respiratory support. In some embodiments, the system may be without a controller and/or I/O interface. A medical professional such as a nurse or technician may provide the necessary control function based on observation of the patient or by using other monitoring equipment(s). In some embodiments where the system 10 has a controller 19 but no I/O interface, the user such as a medical professional may operate the controller 19. In some embodiments, the system 10 may not have a controller 10 and the user may manually operate one or more of the other elements of the system 10 such as the flow source 12, the humidifier 17, the additive gas source 12A and the I/O interface 20. [0148] As noted above, the high gas flow (optionally humidified) may be delivered to the patient 16 via a delivery conduit 14 and the patient interface assembly 15 or 'interface', such as an oral interface, nasal cannula, mask, or combination thereof. In some embodiments, the high gas flow (optionally humidified) may be delivered to the patient 16 for surgical uses, e.g., surgical insufflation. [0149] In some embodiments, the system 10 includes a pressure relief valve or device. The system 10 may include such a pressure relief or regulating device, or pressure limiting device 100 (e.g., a pressure relief valve or PRV). This pressure limiting device 100 may be a valve having features described in WO2018/033863, the entirety of which is incorporated by reference herein. In some embodiments, the system 10 does not include, or excludes a pressure relief valve or device. In some embodiments, the system 10 does not include, or excludes a flow compensated pressure relief valve or device, for example, a flow compensated pressure relief valve having features as described in WO2018/033863. Pressure relief and pressure control are particularly desirable for use in a respiratory support system such as a system 10 for providing high flow respiratory support comprising a non-sealing patient interface 15, to provide an upper limit on pressures that may be generated downstream from the flow source 12 which in turn can impact patient airway pressure (also referred to as patient pressure). Importantly, the upper pressure limit may be configured to provide a safety threshold, to ensure patient pressure safety, and/or to prevent damage to tubes, fluid connections, or other components in the system 10 due to over-pressure. [0150] Figure 2a illustrates a cross-sectional side view of an oral interface 200. The oral interface 200 may form part of the patient interface assembly 15 of Figure 1, for providing respiratory support to the patient 16. Figure 2b and Figure 2c show enlarged portions of Figure 2a containing the gases outlet 220. The oral interface 200 comprises at least one gases inlet 210 for receiving a gases flow 13 from the flow source 12 via the gas delivery conduit 14. The oral interface 200 further comprises at least one gases outlet 220 for providing the gases flow 13 to the patient 16. Figure 2b and Figure 2c show enlarged portions of Figure 2a containing the gases outlet 220. There is a gases flow path 230 defined between the at least one gases inlet 210 and the at least one gases outlet 220. The gases flow path 230 provides a path for the gases to flow from the at least one gases inlet 210 to the at least one gases outlet 220. In other words, the at least one gases inlet 210 and the at least one gases outlet 220 are fluidly connected via the gases flow path 230. [0151] The oral interface 200 further comprises a body 240 having a mouth- engaging portion 250 for engaging with the mouth of the patient 16. The body 240 has a first end opening 260 and a second end opening 270 disposed on opposite sides of the body 240. The body 240 may comprise a unitary part, or may comprise component parts that when assembled form the body. In use, the second end opening 270 is inside the mouth of the patient 16 and proximal the airway of the patient 16 while the first end is distal from the airway of the patient and generally outside the mouth of the patient 16. The first end opening 260 and the second end opening 270 define a channel 280 between them, the channel 280 allowing for access into the mouth of the patient 16 (e.g., through which a medical instrument can access the oral cavity). [0152] The gases flow path 230 between the at least one gases inlet 210 and the at least one gases outlet 220 may be defined by structural features of the body 240. Toward the at least one gases outlet 220, a portion of the gases flow path 230 may be defined between outer wall portion 244 and inner wall portion 242 of the body 240 corresponding to at least part of the channel 280. In some examples, the mouth engaging portion 250 defines an outer wall portion of the body 240.. The inner wall portion 242 may terminate at the second end opening 270 or more proximal to the first end opening 260. In some examples, the inner wall portion 242 and the outer wall portion 244 comprise a restriction. More specifically, the face of the inner wall portion 242 and the face of the outer wall portion 244 in fluid communication with the gases flow path 230 may comprise the restriction. The restriction may comprise all or part of a length of the wall portions corresponding to the channel 280. The restriction may comprise a narrowing between the wall portions that may be defined by a taper, flange, nib, or other structural feature between the wall portions. One or both of the inner wall portion 242 and the outer wall portion 244 defining part of the gases flow path 230 may be tapered. A taper may be provided on one or both of the inner wall portion 242 and the outer wall portion 244 facing towards the gases flow path 230. Alternatively or additionally a taper may be provided on one or both of the inner wall portion 242 and the outer wall portion 244 facing away from the gases flow path 230. For example, the inner wall portion 242 facing the channel 280 may be tapered as shown in Figures 2a to 2c. The gases flow path 230 provides a path for the gases to flow from the at least one gases inlet 210 to the at least one gases outlet 220. In other words, the at least one gases inlet 210 and the at least one gases outlet 220 are fluidly connected via the gases flow path 230. In some examples, at least part of the gases flow path 230 may be arranged concentrically with the channel 280, so that the gases flow path 230 at least partially surrounds the channel 280. [0153] In some examples, the at least one gases outlet 220 may be positioned between the first end opening 260 and the second end opening 270. In use, the gases flow exiting the at least one gases outlet 220 may enter into the channel 280 and subsequently flow inside the channel to then exit via the second end opening 270. In some examples, the gases flow exiting the at least one gases outlet 220 may attach to an interior wall of the body 240 which defines the channel 280. In some examples, the at least one gases outlet 220 may be positioned near the second end opening 270 so that the gases flow exiting the at least one gases outlet 220, may exit at the second end opening 270 directly into of the patient 16. In some examples, if the at least one gases outlet 220 is located at or proximal to the first end opening 260 or between the first end opening 260 and the second end opening 270, the gases flow exiting the at least one gases outlet 220 may enter into the channel 280 and subsequently flow inside the channel to then exit the second end opening 270 into the airway of the patient 16. If however, the at least one gases outlet 220 is located at or proximal to the second end opening 270, the gases flow exiting the at least one gases outlet 220 may exit at the second end opening 270 directly into the airway of the patient 16. [0154] The body 240 may have a first dimension and a second dimension perpendicular to the first dimension, wherein the first dimension is greater than the second dimension. The first dimension ‘c’ may be the distance between the first end opening 260 and the second end opening 270. In some examples the first dimension ‘c’ indicates the length of the oral interface 200. The first dimension ‘c’ may be measured along an axis substantially parallel to the longitudinal axis 290 of the oral interface 200. The second dimension ‘a’ may be along an axis substantially perpendicular to the axis 290 of the oral interface 200. In some examples, the second dimension ‘a’ indicates the height or diameter (in the case of a circular cross section) of the body 240 defining the channel 280. Figure 2a shows schematically the first dimension ‘c’ of the body 240 is greater than the second dimension ‘a’ of the body 240. A third dimension, ‘b’ may be the distance between a cover 310 (when provided) and the second end opening 270. In some examples, the third dimension ‘b’ indicates a length of the mouth-engaging portion 250. The third dimension ‘b’ may be measured along an axis substantially parallel to the axis 290 of the oral interface 200. In some embodiments, the second dimension ‘a’ may be greater than the third dimension ‘b’ as shown in Figure 2a. The third dimension ‘b’ as shown may be a distance measured between the second end opening 270 and an outside edge of the cover 310 intended to face away from the patient when in use. Alternatively, the third dimension ‘b’ may be a shorter distance measured between the second end opening 270 and an inside edge of the cover 310 intended to face towards the patient when in use. In some embodiments, the second dimension ‘a’ (e.g. the height of oral interface channel 280) may be greater than or less than the third dimension ‘b’ (e.g. the length of the mouth-engaging portion 250). In some embodiments, the third dimension ‘b’ may be sized such that mouth engaging portion 250 protrudes into the mouth of the patient without causing an obstruction to the back of the mouth or the airway of the patient 16. It is to be understood that the dimensions ‘a’, ‘b’, and ‘c’ may be selected as necessary for different patient demographics and populations, and that their relative dimensions need not be adhered to in all scenarios. [0155] As explained in further detail below, the oral interface 200 may include a cover 310 disposed around the mouth-engaging portion mouth-engaging portion 250 is a substantially tubular part of the body 240 which is received in the patient’s mouth when the oral interface 200 is in use. The mouth-engaging portion 250 defines part of the channel 280. It will be appreciated that in various embodiments, the cover 310 may sit inside (between the lip and gums, behind teeth etc.) or outside the mouth of the patient 16 to provide a substantial sealing effect around the oral interface 200 and the mouth of the patient 16 such that fluid access to the mouth of the patient is substantially via the channel 280. Accordingly, the dimension ‘b’ may vary depending on the location of the cover 310 with respect to the patient. In some examples part or all of the cover 310 may be formed from a flexible material that may conform to the shape of the inside and/or outside surface of the patient’s mouth. In some examples, the cover 310 may have a convex shape with the apex oriented toward the first end opening 260. [0156] In some embodiments, at least part of the body 240 may have a non-circular cross section transverse to the axis 290. As an example, at least part of the body may be an obround, elliptical, oval, circle, squircle, peanut or kidney shape. In an embodiment, at least part of the body 240 may have an elliptical or obround cross-section transverse to the axis 290. In another embodiment, at least part of the body 240 may have an oval cross-section transverse to the axis 290. In some embodiments, the body 240 may taper such that opposing wall portions of the body are non-parallel, and taper together (or apart) in a direction toward the mouth engaging portion 250. In some examples, the body 240 may have irregular/non-uniform cross-sections along and/or perpendicular to the axis 290. For example, the body 240 may be tapered such that cross-sectional area of adjacent sections perpendicular to the axis 290 may increase or decrease towards the first end opening 260 and/or the second end opening 270. In various embodiments, the mouth-engaging portion 250 or an exterior of the mouth-engaging portion 250 may or may not have the same shape as the body 240 in one or both of the directions transverse and parallel to the axis 290. [0157] The at least one gases outlet 220 may be disposed between the first end opening 260 and the second end opening 270. In some embodiments, the at least one gases outlet 220 may be disposed at the first end opening 260 or proximal to the first end opening 260 and distal from the second end opening 270. For example, the at least one gases outlet 220 may be disposed between the first end opening 260 and the second end opening 270, closer to the first end opening 260. The at least one gases outlet 220 may comprise a restriction configured to increase an average velocity of the gases flow 13 that enters the channel 280 from the gases flow path 230. In an embodiment, the restriction in the at least one gases outlet 220 may provide a jet flow of the gases that flows through the channel 280 towards the airway of the patient 16. In some embodiments, the restriction may be as to direct the flow of gases at an angle relative to e.g. the longitudinal axis 290 as described elsewhere herein. In some examples, a wall portion of the body 240 may be angled to direct the flow of gases 13 into the channel 280 in a desirable direction, In some examples, the restriction may be provided in the gases flow path 230 upstream of the at least one gases outlet 220. In such examples, the velocity of the gases flow 13 out of the restriction may slow before exiting the at least one gases outlet . [0158] A jet flow of gas may be a region of high velocity of gas. A jet flow of gas may have a momentum and/or pressure and/or velocity greater than that of the medium that the jet flow of gas enters. A jet flow of gas may comprise a stream of gases exiting the at least one gases outlet 220 with a higher dynamic pressure than ambient air around the oral interface 200. It will be appreciated that the gases exiting the at least one gas outlet may be affected by patient breathing when in use. However, providing high flows of gases at a higher dynamic pressure than ambient air may aid in clearing CO2 in the patient’s airways when in use. The jet flow of gas may include a velocity that is capable of achieving at least the target patient pressure of at least 1 cmH2O. This pressure may be provided in the vicinity of the exit of the at least one gases outlet 220. For example, downstream of the at least one gases outlet 220 which may be within the body 240 or downstream of the second end opening 270. The velocity of the jet flow of gas may be greater or less than or same as the velocity of a gases flow 13 provided or generated by the flow source 12. The velocity of the jet flow of gas may be greater than the velocity of a gases flow 13 provided or generated by a flow source 12. Additionally, or alternatively, the velocity of the jet flow of gas may be greater or less than the velocity of a gases flow 13 elsewhere in the system 10. In an embodiment, the velocity of the jet flow of gas may be greater than the velocity of a gases flow 13 elsewhere in the system 10. The jet flow of gas may include a velocity in a range of about 5 m/s to about 100 m/s. The jet flow of gas may include a velocity in a range of about 5 m/s to about 60 m/s at a selected flow rate of about 20 L/min to about 100 L/min of the flow of gas provided by the flow source 12. The jet flow of gas may include a velocity in a range of about 5 m/s to about 60 m/s at a selected flow rate of about 20 L/min to about 90 L/min of the flow of gas provided by the flow source 12. [0159] In one or more embodiments of the present disclosure, the restriction may be a nozzle. In other embodiments, the restriction may be an orifice plate (for e.g., a plate comprising one or more discrete outlets, such as in a honeycomb pattern), a venturi or the like. In further embodiments, the restriction may be a single outlet around the entire perimeter of the channel 280 i.e. annular. In some examples, the restriction may be provided between inner and outer wall portions of the body as described elsewhere in this disclosure. The restriction may be shaped and sized such that the average velocity gases flow 13 increases when passing through the restriction 220 and may have the highest average velocity at the point of exit of the at least one gases outlet 220 which then decreases as the gases flow moves towards the back of the mouth of the patient 16 or into the airway of the patient 16. [0160] The gases flow 13 may exit the at least one gases outlet 220 and enter the channel 280 if the at least one gases outlet 220 is located within the channel 280, e.g. at or proximal the first end opening 260, or is located between the first end opening 260 and the second end opening 270. The gases flow may exit the at least one gases outlet 220 near the second end opening 270 if the at least one gases outlet 220 is located at or proximal the second end opening 270 (which is adjacent the airway of the patient 16). The average velocity of the gases flow 13 may be up to about 110m/s, between about 10m/s and about 110m/s and may be between about 40m/s and about 110m/s. Having an average velocity of the gases flow 13 at about 40m/s may produce an airway pressure of about 1cmH2O in the mouth of the patient 16 which may be the minimum desirable airway pressure. In some embodiments, the average velocity of the gases flow 13 may be about 100m/s. In some embodiments, the average velocity of 100m/s of the gases flow 13 may be achieved at a restriction and/or smallest part of the gases outlet 220 for example, nozzle 830. [0161] In one or more embodiments, the at least one gases outlet 220 may be configured to provide the gases flow 13 such that the airway pressure of the patient 16 is at least about 0.1 cmH2O or about 0.2 cmH2O, or about 0.3 cmH2O, or about 0.4 cmH2O, or about 0.5 cmH2O, or about 0.6 cmH2O, or about 0.7 cmH2O, or about 0.8 cmH2O, or about 0.9 cmH2O, or about 1 cmH2O, or about 2 cmH2O, or about 3 cmH2O, or about 4 cmH2O, or about 5 cmH2O, or about 6 cmH2O, or about 7 cmH2O, or about 8 cmH2O, or about 9 cmH2O or about 10 cmH2O. In other embodiments, the at least one gases outlet 220 may be configured to provide the gases flow 13 such that the airway pressure of the patient 16 is between about 0.1 cmH2O and about 10cmH2O or about 0.2 cmH2O to about 7 cmH2O, or about 2 cmH2O to about 7 cmH2O, or about 2 cmH2O to 10cmH2O. [0162] In one or more embodiments, the at least one gases outlet 220 may be disposed along an inner wall portion of the body defining a perimeter of the channel 280. For example, the at least one gases outlet 220 may be an obround/elliptical/oval/circle/squircle/ peanut/kidney shape when disposed along the inner wall of the body 240 defining the channel 280. In one or more embodiments, the gases flow path 230 may be circumferential around the channel 280. Furthermore, in some embodiments, the at least one gases outlet 220 may be provided as a slit along the perimeter of the inner wall of the body defining the channel 280. See for example Figures 2a to 2c. In a yet another embodiment, the at least one gases outlet 220 may be provided as a circumferential slit or opening around an end face of the body portion 240. See for example Figure 3 where the gases flow 13 from the gases flow path 230 can travel directly to the patient’s airway without first travelling through the channel 280. It will be appreciated that the gases flow path 230 and/or the at least one gases outlet 220 may be non-circular around the channel 280 but in operation, the gases flow path 230 along with the at least one gases outlet 220, may be configured to provide an annular gases flow 13 into the channel 280 or at the end of the channel 280 at the second end opening 270. In some embodiments, one or more of the shape, size and configuration (e.g. angle and location) of the at least one gases outlet 220 may allow the average velocity of the gases flow 13 to be substantially uniform around the channel 280. It will be appreciated that in different embodiments, the at least one gases outlet 220 may be annular and non-circular (e.g. obround, elliptical, oval, circle, squircle, peanut, kidney shape etc.) or annular and circular. [0163] Figure 3 illustrates a cross-sectional side view of an oral interface 200 for use as part of the patient interface assembly 15 of Figure 1, for providing respiratory support to the patient 16 according to another embodiment of the disclosure. The oral interface 200 comprises at least one gases inlet 210 for receiving a gases flow 130 from the flow source 12 (not shown) via the gas delivery conduit 14 (not shown). The oral interface 200 further comprises at least one gases outlet 220 for providing the gases flow 13 to the patient 16. While in this and other examples, the composition of the gases flow 130 at the gases inlet 210 will remain the same in the gases flow 13 at the at least one gases outlet 220, flow properties of the gases flow 130 and the gases flow 13 will be different since the at least one gases outlet comprises a restriction configured to increase an average velocity of the gases in the gases flow path 230. In some examples, the restriction gives rise to a jet flow of gases as described above. [0164] The oral interface 200 further comprises a body 240 having a mouth- engaging portion 250 for engaging with the mouth of the patient 16. The body 240 has a first end opening 260 and a second end opening 270 disposed on opposite sides of the body 240. In use, the second end opening 270 is inside the mouth of the patient 16 and proximal the airway of the patient 16 while the first end opening 260 is distal from the airway of the patient and generally outside the mouth of the patient 16. The first end opening 260 and the second end opening 270 define a channel 280 (not shown) between them, the channel 280 allowing for access into the mouth of the patient 16 (e.g., through which a medical instrument can access the oral cavity). [0165] The at least one gases outlet 220 in Figure 3 may be disposed at the second end opening 270 or proximal to the second end 270 and distal from the first end opening 260. In other words, the at least one gases outlet 220 may be located in the same plane as that of the second end opening 270, or close to it. The gases flow path 230 and the at least one gases outlet 220 may be defined by structural features of body 240 as described above. [0166] Figure 4 illustrates a perspective side view of the oral interface 200 viewed from the patient’s end when in use. The gas or gases from the flow source 12 flow through the gas delivery conduit 14 into the at least one gases inlet 210. Subsequently, the gases then flow through the gases flow path 230 to the at least one gases outlet 220 where they exit into the channel 280 that is defined between the first end opening 260 and the second end opening 270. The body 240 of the oral interface 200 can also be seen in Figure 4. [0167] Figure 5 illustrates the oral interface 200 of Figure 4 from a front view (that faces away from the patient 16 when in use) according to some embodiments of the disclosure. Figure 6 illustrates the oral interface 200 of Figures 4 and 5 from a back view (that faces towards the patient 16 when in use) according to some embodiments of the disclosure. Figure 7 illustrates the oral interface 200 of Figures 4 to 6 from a top view according to some embodiments of the disclosure. The oral interface 200 may include a cover 310 disposed around the mouth- engaging portion 250 of the body 240. The mouth-engaging portion 250 is configured to be inside the mouth of the patient 16 when in use. The cover 310 may be disposed around a section of the mouth-engaging portion 250 for location between the lips and the teeth, or behind the teeth, of the patient 16. The cover 310 may be substantially flexible and provide a substantial seal around the mouth-engaging portion 250 of the oral interface 200 to prevent or reduce any fluid leak from the mouth of the patient 16 e.g., from between the teeth and the lips of the patient 16. The cover 310 may also be beneficial in ensuring that fluid access to the mouth of the patient 16 may be substantially via the channel 280. In use, the mouth-engaging portion 250 has an elongate structure and would be inside the mouth of the patient 16 configured to act as a bite block to aid in preventing the mouth of the patient from closing and/or the teeth of the patient biting the tongue of the patient 16. [0168] The oral interface 200 may also include headgear connectors 320 that can be removably connected via attachment loops 330 to a headgear that may be wearable by the patient 16. In use, when the oral interface 200 is placed on the mouth of the patient 16, the headgear connectors 320 may aid in keeping the oral interface 200 in place by way of straps going through the attachment loops 330 and connecting to the headgear that may be placed on or around the head of the patient 16. The headgear connectors 320 may be configured to also provide a substantial seal e.g. with the cover 310 the outside corners the mouth of the patient 16. It will be appreciated that other types of connectors or place holders may be used to assist with holding the oral interface 200 down and in place when in use. [0169] Air entrainment via the channel 280 may occur when the pressure in the channel 280 is lower than the pressure in the external surroundings (e.g. ambient). Areas of low pressure may occur when the gases flow travels at a speed greater than the speed of the ambient gases proximal to the outlet of channel 280 or during inhalation when the inspiratory flow of the patient may be greater than the delivered gases flow through the oral interface 200. Air entrainment may or may not cause a reduction in pressure and may cause dilution of gases provided to the patient 16 when gases having a composition of greater than 21% O2 are provided to the patient. [0170] Figures 8 and 9 illustrate oral interface 200 with gases flow path 230 having an asymmetrical and constant cross-sectional area respectively. The internal shape of the gases flow path 230 may aid in establishing constant pressure around gases flow path 230. Figure 8 illustrates oral interface 200 with a single gases inlet 210. In this embodiment, the cross- sectional area of the gases flow path 230 further from the gases inlet 210 (shown as 610 in Figure 8) may be smaller than the cross-sectional area of the gases flow path 230 nearest to the gases inlet 210 (shown as 620 in Figure 8). Accordingly, static pressure in the gases flow path 230 may be equalised by way of the non-uniform cross-sectional area of the gases flow path 230. It would be appreciated that if the cross-sectional area of the gases flow path 230 was constant, unequal velocities of gases may exit the oral interface 200 through the at least one gases outlet 220. Such non-uniformity in gases flow may be undesirable since it may cause differential pressures in the oral cavity which may lead to difficulty associated with elevating airway pressure and/or air entrainment. [0171] Figure 9 illustrates oral interface 200 with two gases inlets 210A, 210B and a constant cross-sectional area. In an embodiment where the oral interface 200 includes two or more gases inlets 210 around the periphery of the gases flow path 230, the gases flow path 230 may have a constant cross-sectional area and be able to deliver gases with consistent flow parameters (such as flowrate, speed, pressure etc). In other words, the cross-sectional area at 610 and 620 in Figure 9 is equal. Accordingly, when the gases enter through the two gases inlets 210A, 210B, there may be relatively more even pressure within the gases flow path 230 when the gases flow path 230 has a uniform cross-sectional area. [0172] Figures 10 to 12 illustrate various possible orientations of the at least one gases inlet 210 relative to the longitudinal axis 290 of the oral 200. The axis 290 extends longitudinally along the channel 280. In Figure 10, a longitudinal axis 291 of the at least one gases inlet 210 along a length of the gases inlet may be substantially parallel to the longitudinal axis 290 of the oral interface 200. In Figure 11, the longitudinal axis 292 of the gases inlet 210 may be at an angle α which is substantially acute to the longitudinal axis 290 of the oral interface 200. In Figure 12, the longitudinal axis 293 of the gases inlet 210 may be substantially perpendicular i.e., α = 90° to the axis 290 of the oral interface 200. The angle α may be greater than 90° is some cases. In various embodiments, the axis 291, 292 and 293 may be angled along any of the x-, y- or z-axis of the body 240 depending on one or more factors such as the application of the oral interface 200, comfort of use for the patient 16 and so on. It will be appreciated that the above-mentioned orientations are not to be taken as limitations and that other orientations may be possible without departing from the scope of the disclosure. [0173] Having the longitudinal axis 293 of the gases inlet 210 substantially perpendicular to the longitudinal axis 290 of the oral interface 200 (as shown in Figure 12) and in some embodiments, locating the coupling of the gases inlet 210 at a further distance from the oral interface 200, may be advantageous by avoiding having the gases inlet 210 too close to the mouth of the patient 16 and reducing the space available near or around the mouth of the patient for access/performing medical procedures. In some embodiments, the gases inlet 210 may be located to sit along the cheek of the patient 16 when in use, and may be oriented generally posteriorly for connecting with a coupling supplying the gases flow 130 to the gases flow path 230. In one non-limiting example, α may be about 135° and the gases inlet 210 may be oriented in a plane that transects the longitudinal axis 290. The plane may be orthogonal to the longitudinal axis 290. In other examples, the plane may not be orthogonal to the longitudinal axis 290, and the gases inlet 210 may be oriented to provide a low profile relative to the patient’s facial anatomy such that the conduit of the gases inlet 210 sits close to the contours of the patient’s face when in use. In some examples, the conduit of the gases inlet 210 may be preformed or flexible to follow the contours of the patient’s face when in use. This may be advantageous since it can minimise interference with the clinician’s access to the patient. [0174] Figures 13 to 18 illustrate examples of a restriction in the at least one gases outlet 220 configured at various angles with respect to the horizontal longitudinal axis 290. Figures 19 to 21 illustrate examples of the gases outlet 220 at varying locations with respect to the plane of the first end opening. The angle and/or the location of the at least one gases outlet 220 may impact the direction of the gases flow into the channel 280 as will be explained in more detail below. In some embodiments, the restriction in the gases outlet 220 may be a nozzle. In some embodiments, the nozzle may be configured to towards the end of the outflow end of the gases into the channel 280. [0175] Figure 13 illustrates a nozzle 820 oriented or directed at an angle of about 0 degrees to a longitudinal axis 290 of the body 240 (the axis 290 extends between the first end opening 260 and the second end opening 270 as can be seen in Figure 2) according to an embodiment of the disclosure. Figure 14 illustrates the flow of gases inside the channel 280 of the body 240 during use of the oral interface of Figure 13. The flow patterns as illustrated in Figure 14 are representative of when the gases flow 13 exits the nozzle 820 (in the absence of patient breathing effects) such that the gases flow 13 travels further into the channel 280 and towards the mouth of the patient 16. In this embodiment, the at least one gases outlet 220 which comprises a nozzle 820 may be configured to direct the gases flow 13 in a direction substantially parallel to the axis 290. As can be seen from Figure 14, most if not all, of the gases exiting the gases flow path 230 through the nozzle 820 and entering the channel 280, travel towards or in the direction of the second end opening 270 (towards the airway of the patient 16) before turning back towards the first end opening 260 and out of the oral interface 200. [0176] In Figure 14, the streamlines represent an approximation of gases flow 13 from the nozzle 820 during operation of the oral interface 200 of Figure 13, i.e. when the gases inlet 210 is coupled with a gas flow 130 from e.g. a blower or other gas source. The approximation is in the absence of patient breathing effects. The gases flow 13 will travel deeper into the channel 280 dependent on the total pressure the gases flow has when exiting the nozzle 820. For example, the higher the dynamic pressure the further the gases flow 13 will travel into the channel 280. In some cases the gases flow 13 will travel past the channel 280. In use, gases travelling past the channel enter the patient’s airway. Gases flow 13 with higher pressure may stagnate further into the channel 280 and closer to the second end opening 270. In some examples, a gases flow 13 may stagnate at a point where gases flow 13 completely stops, momentarily or otherwise. [0177] Figure 15 illustrates a nozzle 830 oriented or directed at an angle of about 45 degrees to a longitudinal axis 290 of the body 240. The axis 290 extends between the first end opening 260 and the second end opening 270 as can be seen in Figure 2. In Figure 16 the streamlines represent an approximation of the gases flow 13 inside the channel 280 of the body 240 during operation of the oral interface of Figure 15, i.e. when the gases inlet 210 is coupled with a gas flow 130 from e.g. a blower or high pressure supply of gases or other gas source. The approximation is in the absence of patient breathing effects. In this embodiment, the at least one gases outlet 220 which comprises a nozzle 830, be configured to direct the gases flow 13 to converge from the first end opening 260 towards the second end opening 270. As can be seen from Figure 16, due to the nozzle 830 being oriented or directed at an angle of about 45 degrees (β) to an axis 290 of the body 240. Gases exiting the gases flow path 230 through nozzle 830 initially travel in a direction substantially along axis 294 when entering the channel 280, and travel towards the central part of the channel 280. Some of the gases then travel towards or in the direction of the second end opening 270 closer to the airway of the patient 16 before turning back towards the first end opening 260. The remaining travel towards the first end opening 260 and out of the oral interface 200. [0178] Figure 17 illustrates a nozzle 840 oriented to open at an angle of about 90 degrees to a longitudinal axis 290 of the body 240. The axis 290 extends between the first end opening 260 and the second end opening 270 as can be seen in Figure 2. In Figure 18 the streamlines represent an approximation of the gases flow 13 inside the channel 280 of the body 240 during operation of the oral interface of Figure 17, i.e. when the gases inlet 210 is coupled with a gas flow 130 from e.g. a blower or high pressure supply of gases or other gas source. The approximation is in the absence of patient breathing effects.. As can be seen from Figure 18, due to the nozzle 840 being oriented or directed at an angle of about 90 degrees (β2) to an axis 290 of the body 240, most if not all of the gases exiting the gases flow path 230 through the nozzle 840 and entering the channel 280, initially travel substantially perpendicular to the axis 290 of the body 240 into the channel 280. Some of the gases then travel towards or in the direction of the second end opening 270 and then turn back towards the first end opening 260. The remaining gases travel towards the first end opening 260 and then out of the oral interface 200 into ambient air. In Figure 18, gases flow from the nozzle 840 will stagnate closer to the first end opening 260 which may cause air to travel towards a region of lower pressure (ambient air). It will be appreciated that the patterns of gases flow 13 illustrated in Figures 14, 16, 18 are merely indicative of major flow characteristics of the gases flow 13 and may not be to scale or accurate by proportion. It will be further appreciated that the patterns of gases flow 13 illustrated in Figures 14, 16, 18 are not a depiction of results of simulation or the exact flow patterns but rather, are an expected approximation. [0179] Figure 19 is a sectional perspective view of a body 240 having a non-circular, e.g. obround shape, with the at least one gases outlet 220, e.g. nozzle 830, disposed around an inner wall portion 242 of body 240 at a substantially constant exit angle of 45° relative to longitudinal axis 290 of the oral interface 200. Broken lines 410 represent schematically the direction of a flow exiting the gases outlet 220. In some embodiments, it may be desirable to direct the gases flow to converge towards a In the example shown, the flow represented by broken lines 410 converges toward a point 920 which may be considered to lie in a first reference plane, RF1 which orthogonally transects longitudinal axis 290. The nozzle 830 is disposed around a body 240 which has a non-circular cross sectional shape. Therefore, in order to achieve convergence of gases towards a point 920 with a substantially constant 45° exit angle, the distance between nozzle 830 and the point of convergence 920 varies along a path 930 on the inner wall portion 242 of the body 240. That is, if the nozzle 830 provides a substantially constant exit angle for gases exiting the flow path 230, the position (i.e. relative distance to the point of convergence) of the nozzle 830 in the inner wall portion 242 of the body 240 must vary. In the example shown, this variation is substantially continuous. This is shown in the figures with use of reference planes designated “RF” which transect longitudinal plane 290 orthogonally but which, for simplicity, are shown as a single broken line. In this example, the point of convergence of gas flow 13 exiting the nozzle lies at RF1. The shortest distance between the nozzle 830 and the point of convergence 920 is between RF1 and a second reference plane RF2 which orthogonally transects longitudinal axis 290. RF2 is located where the distance between opposing parts of body 240 comprising the nozzle is smallest. The largest distance between the nozzle 830 and the point of convergence 920 is between RF1 and RF3. RF3 also orthogonally transects longitudinal axis 290 and is located where the distance between opposing parts of the body 240 comprising the nozzle is largest (i.e. the widest section of the body 240). The distance between the nozzle 830 and the point of convergence 920 at intermediate positions along path 930 are found between the reference planes RF2 and RF3. It will be appreciated that the point of convergence 920 may be located closer to the inlet 260 or closer to the outlet 270 e.g. by shifting the nozzle location closer to the inlet 260 or closer to the outlet 270 while keeping the exit angle of the nozzle substantially constant. In some circumstances, flow convergence onto point 920 may not be possible when gases exiting the nozzle 830 are of low velocity. However low velocity gases may still take the path shown by broken lines 410 converging toward point 920, albeit without fully converging onto point 920. [0180] Figure 20 is a sectional perspective view of a body 240 having a non-circular e.g. obround shape, with the at least one gases outlet 220 (e.g. nozzle 830) disposed around an inner portion 242 of body 240 in a reference frame RF7 which orthogonally transects longitudinal axis 290. Broken lines 410 represent schematically the direction of a flow exiting the gases outlet 220. In the example shown, the flow converges toward a single point 920 which may be considered to lie in a reference plane RF6 which orthogonally transects longitudinal axis 290. Since nozzle 830 is disposed around a body 240 which has a non-circular cross sectional shape, and there is a substantially constant distance between reference planes RF6 and RF7 ,the exit angle β of the gases outlet 220 must path 930 on the inner surface of the body 240 in order to achieve convergence toward point 920. In the example shown, the variation is substantially continuous. In the example shown, the exit angle β may be a first angle at a location on path 930 where the distance between opposing parts of the nozzle 830 is largest (i.e. the widest section of the body 240), and the exit angle β may be a second angle at a location on path 930 where the distance between opposing parts of the nozzle 830 is smallest (i.e. the narrowest section of the body 240), where the first angle is larger than the second angle. In one example, the first angle may be about 56° and the second angle may be about 45°. The exit angle of the nozzle 830 at intermediate positions along path 930 vary between the first angle and the second angle in order to direct the flow of gases toward the point of convergence 920. It will be appreciated that the distance between the gases outlet comprising nozzle 830 and the point of convergence 920 remains substantially constant. In some circumstances, flow convergence to point 920 may not be possible when gases exiting the nozzle 830 are of low velocity. However low velocity gases may still take the path shown by broken lines 410 converging toward point 920, albeit without fully converging on point 920. [0181] It will be appreciated that in some embodiments, the distance of the nozzle 830 to the point of convergence 920 may be variable. A location of the point 920 may be based on one or more parameters such as an angle, and/or size and/or shape and/or location of the restriction and/or the gases outlet 220 (when the restriction is provided upstream of the gases outlet 220), a cross-sectional width of the gases flow path 230, a shape of the at least one gases inlet 210, average velocity of the gases flow 13. [0182] Figure 21 is a sectional perspective view of a body 240 having a non-circular e.g. obround shape, with at least one gasses outlet 220, e.g. nozzle 830, disposed around the inner portion of body 240. In this figure, there is a substantially constant exit angle β for the gases, and the gases outlet 220 is positioned in an inner wall portion 242 of body 240 in a single plane that orthogonally transects the longitudinal axis 290 so that gases converge toward a line 950. That is, nozzle 830 is disposed at a substantially constant exit angle for the gases of about 45° relative to longitudinal axis 290 of the oral interface 200. In the example shown, owing to the non-circular e.g. obround shape of the body 240, the flow represented by lines 410 converges toward a line 950 which may be considered to lie in a reference plane, RF8 which orthogonally transects longitudinal axis 290. Given the substantially constant 45° exit angle of gases and the non-circular shape of the body 240 around the gases outlet 220, the distance between nozzle 830 and the line of convergence 950 is substantially constant. [0183] Figure 22 is a side sectional view of a body 240 having a substantially circular shape, with the at least one gases outlet 220, 830 disposed around the inner portion of 240 at a substantially constant angle of 45° relative to longitudinal axis 290 of the oral interface 200. In this figure, there is a substantially constant exit angle β for the gases and the gases outlet 220 is positioned in an inner wall portion 242 of body 240 in a single plane that orthogonally transects the longitudinal axis 290. Because the inner wall portion 242 of body 240 is substantially circular, the gases converge toward a point 920. Broken lines 410 represent schematically the direction of a flow exiting the gases outlet 220. In the example shown, the flow represented by broken lines 410 converges toward a point 920 which may be considered to lie in a reference plane, RF4 which orthogonally transects longitudinal axis 290. Given the substantially constant 45° exit angle of gases and the circular shape of the body 240 around the gases outlet 220, the distance between nozzle 830 and the point of convergence 920 is substantially constant. It will be appreciated that the point of convergence 920 may be located closer to the inlet 260 or closer to the outlet 270 e.g. by shifting the nozzle location closer to the inlet 260 or closer to the outlet 270 while keeping the exit angle of the nozzle substantially constant. In some examples, the exit angle β of the gases outlet may be decreased in order to locate the point of convergence 920 closer to the outlet 270, or it may be increased in order to locate the point of convergence closer to the inlet 260. In some circumstances, flow convergence onto point 920 may not be possible when gases exiting the nozzle 830 are of low velocity. However low velocity gases may still take the path shown by broken lines 410 toward point 920, albeit without fully converging onto point 920. In some examples, to achieve convergence substantially along axis 290 and closer to the outlet 270 the exit angle β of the gases outlet may be close to zero, such that the flow of gases is substantially parallel with respect to axis 290. [0184] The examples of Figures 13 to 22 demonstrate that the location and/or orientation of the at least one gases outlet 220 to control the position and exit angle of the flow of gases can be selected to achieve different flow patterns within the channel 280 and/or the patient’s airway. It is to be understood, however, that convergence of the flows may also be affected by patient breathing and other factors when in use. In some examples, controlling the location and exit angle of the gases outlet 220 to converge toward a point or line closer to the patient’s airway can assist the gases to travel deeper into the channel 280. When the exit angle is very small, such as approaching or about 0 degrees to the axis 290 (see e.g. Figure 14), the gas flow may travel deeper into the channel 280 but remain closer to the walls. This may be advantageous since instruments inserted into the channel 280 may have less disruptive effect on the gas flow when it is directed substantially along the channel walls, rather than centrally of the channel 280. In another example, when the exit angle is larger, such as approaching or about 90 degrees to the axis 290 (see e.g. Figure 18), the gases flow may as a curtain and reduce the amount of ambient air entering the patient’s airway via the channel 280. [0185] In some embodiments, gases may exit the oral interface at velocities around 80m/s to 100 m/s. The gases may have the highest dynamic pressure at or proximal to where gases exit the nozzle (820, 830 or 840). As the gases flow through the channel 280 toward the patient’s airway, the flow may slow and the dynamic pressure may be converted into static pressure. The point where the gases turn inside the mouth may be referred to as a momentary stagnation zone. [0186] The restriction, which may be formed by a nozzle (820, 830, 840), forms a jet flow inside the oral interface 200. In some embodiments, the nozzle (820, 830 or 840) may be a circumferential nozzle around the channel 280 creating a circumferential (or “annular”) jet flow inside the oral interface 200. This may be beneficial in creating a high-pressure region that covers a large cross-sectional area inside the mouth of the patient. In a mouth-open procedure, this would provide additional pressures that may prevent the airway from collapsing. Beneficially, this may also assist in providing clearance of CO2 from the patient’s airway. It will be appreciated that it is not essential for the jet flow to be completely circumferential. Thus, the nozzle need not be formed by a single continuous slit or opening. However, one or more gaps in the circumferential jet flow profile may create areas of low resistance to flow of gases. The one or more gaps in the circumferential jet flow profile may allow for ease of flow exit from the mouth of the patient 16. This may subsequently reduce the amount of pressure generated within the oral interface 200 and in turn the mouth of the patient 16, which could be beneficial in easing expiratory effort by the patient 16. [0187] During inhalation, the gases provided through the gas flow path 230 of oral interface 200 may travel further into the airway of the patient 16. During exhalation, the exhaled gases may collide with the gases flow 13 from the oral interface 200 and be met with a high resistance provided by the static (and any momentary stagnation) pressure produced by the jet flow. The patient-generated pressures and flow may concurrently push the gases flow 13 provided through the oral interface 200 close towards the first end opening 260. [0188] In some embodiments, the flow rate of the gases flow 13 may be between about 0LPM and about 120LPM such as between about 20LPM and about 120LPM. [0189] In one or more embodiments of the disclosure the at least one gases outlet 220 (configured as e.g. a circumferential slit) may an exit angle for gases of about 0 degrees to the axis 290 of the oral interface 200 and the at least one gases outlet 220 may have a width of about 0.15mm. In such examples, the static or stagnation pressure may be about 3.6 cmH2O at the back of the mouth of the patient 16 when the flow rate is 70LPM and about 0.6 cmH2O at the back of the mouth of the patient 16 when the flow rate is 30LPM. [0190] In one or more embodiments of the disclosure the at least one gases outlet 220 (configured as e.g. a circumferential slit) may be at an angle of about 45 degrees to the axis 290 of the oral interface 200 and the at least one gases outlet may have a width of 0.2mm. In such examples, the static or stagnation pressure may be about 2.6 cmH2O at the back of the mouth of the patient 16 when the flow rate is 70LPM and about 0.4 cmH2O at the back of the mouth of the patient 16 when the flow rate is 30LPM. [0191] In one or more embodiments of the disclosure the at least one gases outlet 220 (configured as e.g. a circumferential slit) may be at an angle of about 45 degrees to the axis 290 of the oral interface 200 and the at least one gases outlet may have a width of about 0.1mm. In such examples, the static or stagnation pressure may be about 0.2 cmH2O at the back of the mouth of the patient 16 when the flow rate is 30LPM. [0192] In one or more embodiments of the disclosure the at least one gases outlet 220 (configured as e.g. a circumferential slit) may be at an angle of about 90 degrees to the axis 290 of the oral interface 200 and the at least one gases outlet may have a width of about 0.5mm. In such examples, the static or stagnation pressure may be about 0.1 cmH2O at the back of the mouth of the patient 16 when the flow rate is 30LPM. [0193] The ranges quoted in the examples provided relate to, and can be ascertained by, bench testing the oral interface 200 on a non-human 3D rigid airway model with jaw-thrust. [0194] Accordingly, it may be understood that when the jet flow enters the channel 280 at an angle perpendicular to the axis 290 of the body 240, most of the gases flow 13 will travel outside to the atmosphere thereby generating little or no pressure at the back of the mouth of the patient 16. It will further be appreciated that the higher velocity of the jet flow achieved (and dependent on the driving pressure), the greater the static pressure in the upper airway of the patient 16. [0195] It will be appreciated that convergence of the gases flow to an imaginary line, plane or point may not strictly be achieved or required. one or more of the angle of the nozzle, distance of the nozzle from the first end opening 260, width of the gases outlet 220 or other parameters may impact the convergence profiles of the gases flow. It will further be appreciated that the distance from the nozzle to the point/line of convergence may depend on the geometry of the gases flow path 230 and the exit angle β of the nozzle 830. It will also be appreciated that altering the width of the one or more gases outlet 220 (i.e. where opposing parts defining the gases outlet 220 are separated by the shortest distance, which may be located at the opening of the gases outlet 220 into channel 280) can alter the profile of gases entering the channel 280. [0196] Figure 23 illustrates a patient interface assembly 15 including an oral interface 200 and a nasal interface 1010. The patient interface assembly 15 may be configured as a non- sealing mask. The nasal interface 1010 and the oral interface 200 may receive a gases flow 13 from a common flow source 12. The gases flow 13 from the common flow source 12 enters the oral interface 200 via the at least one gases inlet 210. The gases flow 13 from the common source 12 also enters the nasal interface 1010 via a nasal conduit 1012 and exits into the nares of the patient 16 via nasal prongs 1014. Figure 24 illustrates the gases flow 13 from the common flow source 12 into the oral interface 200 and the nasal interface 1010 of Figure 23. The gases flow 13 from the common flow source 12 enters the oral interface 200 via the at least one gases inlet 210 and flows through the gases flow path 230 before exiting into the channel 280 via the at least one gases outlet 220. Figure 24 illustrates gases flow 13 passing through the gases flow path 230 and exiting the one or more gases outlets 220 of the oral interface 200 either at or proximal the second end opening 270, or one of at or proximal the first end opening 260 or between the first end opening 260 and the second end opening 270 and into the channel 280 and subsequently flowing towards the back of the mouth of the patient 16. While the direction of flow into the channel 280 appears to originate from seven discrete openings 220, it is to be understood that this is illustrative only and that the gases outlet 220 may comprise a continuous slit around the channel 280, or any suitable number of discrete openings 220 as would be understood by one of skill in the art in the context of the present disclosure. [0197] In an alternative embodiment, the nasal interface 1010 and the oral interface 200 may receive gases flow 13 from separate flow sources. [0198] In an alternative embodiment, the nasal interface 1010 may create a seal with the patient’s face. For example, the sealing interface may comprise a nasal cannula, nasal pillows or a nasal mask. The sealing interface need not provide gases to the patient. For example, the sealing nasal interface may comprise a nasal clip. The nasal clip may obstruct or block flow between the patient’s nasal passages and the patient’s nasal passages, e.g. ambient air. [0199] The nasal interface 1010 as used herein refers to devices such as a cannula, a nasal mask, nasal pillows, or other type of nasal device or combinations thereof configured, in some embodiments, to direct a flow of gas into one or both nares of the patient. [0200] A nasal cannula is a nasal interface that may include one or more prongs 1014 that are configured to be inserted into one or both of a patient’s nasal passages. A mask refers to an interface that covers a patient’s nasal passages and/or mouth. [0201] The patient interface assembly 15 may further comprise mounts and/or supports, e.g., cheek supports, for attaching and/or supporting the gas delivery conduit 14 or conduits on the patient’s face. Alternatively, or additionally, the patient interface assembly 15 may be held in place via one or more head straps or headgear as discussed with reference to Figures 4 to 6. [0202] The nasal interface 1010 may provide a first gases flow to the patient 16 at a first flow rate and the oral interface 200 may provide a second gases flow to the patient 16 at a second flow rate. In an embodiment, the first flow rate is different to the second flow rate. In an embodiment, the first flow rate and the second flow rate may be between about 0LPM and about 120LPM such as between about 20LPM and about 120LPM. In another embodiment, the first gases flow and the second gases flow may have a combined flow rate of between about 0LPM and about 120LPM. [0203] The flow path in the nasal interface 1010 may be fluidly connected with the oral interface 200. Figure 25 illustrates the nasal interface 1010 fluidly connected to the oral interface 200 at the base of the nasal interface 1010 via an interface connector 1110. The interface connector 1110 may allow the nasal interface 1010 to be removably attached to the oral interface 200. [0204] Figure 26 illustrates the gases flow 13 when the nasal interface 1010 is fluidly connected to the oral interface 200 at the base of the nasal interface 1010 via the interface connector 1110 as in Figure 25. The gases flow 13 may be received from the flow source 12 into the nasal interface 1010 and flow into the nose of the patient 16 via the nasal prongs 1014 as well as through the interface connector 1110 into the gases flow path 230 and exit the one or more gases outlets 220 of the oral interface 200 either at or proximal the second end opening 270, or one of at or proximal the first end opening 260 or between the first end opening 260 and the second end opening 270 and into the and subsequently flow towards the back of the mouth of the patient 16. [0205] Figure 27 illustrates an alternate embodiment including the nasal interface 1010 and the oral interface 200 connected via the interface connector 1110. In this embodiment, the gases flow 13 may be received from the flow source 12 into the gases inlet 210 and flow through the gases flow path 230 via the one or more gases outlets 220 into the channel 280 or to the second end opening 270 depending on the location of the one or more gases outlets 220. Further, the gases flow 13 travels from the gases flow path 230- in the oral interface 200 through the interface connector 1110 into the nasal interface 1010 and into the nose of the patient 16 via the nasal prongs 1014. It will be appreciated that, as in Figure 24, the arrows representing gas flow shown in Figures 25, 27, 28 merely show that there is a flow present in the nasal interface 1010 and the oral interface 200 when connected to a flow source 12 and are not to be taken as depiction of the actual direction or distribution of flows. [0206] Figure 28 illustrates another embodiment of a patient interface assembly 15 including the oral interface 200 and the nasal interface 1010. The oral interface 200 may receive a gases flow 13 from a flow source 12a into the gases inlet 210 and flow through the gases flow path 230 into the channel 280 via the one or more gases outlets 220. The nasal interface 1010 may receive a gases flow 13 from another flow source 12b. [0207] The configurations shown in Figures 25 to 27 may be beneficial in the provision of selective delivery of separate therapies or modes of support to a patient using different patient interfaces. Alternatively or additionally, the configurations shown in Figures 25 to 27 may be beneficial in stopping the delivery of a therapy from an interface. Advantageously, the configuration of Figures 25 to 27 in particular may find application in emergency resuscitation, and/or intubation of a patient receiving high flow therapy, during ear, nose, and throat (ENT) surgery, in assisting with conditioning/preoxygenating a patient in a pre-operative state prior to administration of anaesthetics, during post-extubation, sedation e.g. gastroscopies and recovery. [0208] Using the oral interface 200 in conjunction with an unsealed nasal interface 1010 supplying high flow of gases may result in a greater pressure support for the patient 16 compared to using one or the other by itself. This is because flows provided to both the nose and mouth of the patient 16 may result in a higher resistance to exhaled gases. A synergistic effect may be produced when high flow respiratory support via a high flow nasal interface 1010 such as a nasal cannula and high flow respiratory support via the oral interface 200 are concurrently provided. [0209] In some examples, it may be desirable to provide selective delivery of separate therapies to the patient using different patient interface. Particular applications in which this may be desirable include in emergency resuscitation, around intubation of a patient receiving high flow therapy, ear, nose, and throat (ENT) surgery, in assisting with conditioning of a patient in a pre-operative state prior to administration of anaesthetics, and during post-extubation and recovery. In some cases, particularly involving ENT surgery, an oral interface 200 according to the present disclosure may be provided, optionally in conjunction with a nasal interface 1010, to provide a first respiratory support. A face mask assembly 300 may be used as or with a second respiratory support subsystem and/or to deliver one or more substances other than a substance delivered by the oral interface 200, for example anaesthetic agents or oxygen, to the patient, or the same substance but at different flow and/or pressure levels. [0210] The embodiment shown in Figure 29 allows for the delivery of gas from multiple sources via two respiratory support subsystems. Additionally, this configuration may allow the oral interface 200 to be left on the patient throughout the surgical procedure and/or into recovery (whether or not the patient continues to receive flow therapy through the oral interface 200 with or without the nasal interface 1010 throughout the procedure). In the embodiment shown, face mask assembly 300 comprises a full face mask 302 configured to cover both the patient's nose and mouth. In other configurations, the face mask 300 may be a nasal mask or oral mask which is placed over the oral interface 200 to cover only the patient's nasal region or only the patient's mouth, respectively. As shown, the face mask 302 comprises a seal region 304 adapted to seal against the patient's face. The face mask assembly 300 is connected to a second gas source, which supplies the one or more other gases to the patient via the face mask. That is, the second gas source is preferably different from the flow source 12 supplying gas to the oral interface 200. For example, the face mask assembly 300 may be connected to a separate gas source or a separate respiratory support device which may be e.g. a ventilator, a CPAP, a high flow therapy device or a manual resuscitator (for example a handheld face mask with bag). Alternatively the mask assembly 300 could be connected to an anaesthetic device and anaesthetic gas, or air, or oxygen, or a combination of gases, can be delivered via the mask 302. [0211] In some examples, one and the same respiratory support system may supply gases to the oral interface 200 and the face mask 300. [0212] There may be a filter element 400 between the face mask 300 and the second gas source. [0213] The embodiment shown in Figure 29 allows for the delivery of gas from multiple sources via at least two different respiratory support modes, and further allows a doctor, clinician or medical professional to quickly and easily change the type of respiratory support mode. [0214] In one particular application, a patient preparing for anaesthesia can be pre- oxygenated by delivering a high flow of oxygen via a nasal cannula 1010. The oral interface 200 may also be in position on the patient in preparation for a procedure requiring oral instrument access. In some circumstances, anaesthesiologists managing the sedation of the patient 16 may want to switch between delivery of gas flow from one patient interface, such as a nasal cannula 1010 and delivery of gas flow from another patient interface, such as via a face mask 300. Delivery of gas from a nasal cannula together with gas from a mask, or even delivery of gas from a cannula while a mask is placed over the cannula, may cause an increase in pressure, which could damage the patient's lungs. Anaesthesiologists also use a mask with a bag to oxygenate a patient, and in some instances find it more comfortable to use a bag mask if a patient's vital signs being to drop. In such a situation, providing a flow of gas through the cannula 1010 and/or oral interface 200 as well as pulsing gases flow from a bag mask 300 can cause over pressure in the lungs and potential lung damage. In some examples, the aforementioned risk of lung damage may be mitigated by “switching” between modes of respiratory support e.g. using a conduit having one or more portions that are configured to transition between conditions to alter the flow of gas, as described below. Thus, in some situations a medical professional may wish to switch between different respiratory systems or support modes. In first mode respiratory support may be provided by first respiratory support system (for example via the oral interface 200 with or without nasal cannula 1010) and in a second mode respiratory support may be provided by a second respiratory support system (for example via the mask 300), with the support from the first system reduced or switched off. In some cases, additional flow from the oral interface 200 and/or nasal cannula 1010 may also modify the expected behaviour of the anaesthetic circuit, and therefore it may be advantageous to be able to turn the additional flow from the first respiratory system off. In some cases, the flow from the oral interface 200 and/or nasal cannula 1010 may be adjusted to very low flow rates and/or pressure in response to switching. [0215] In some configurations, switching between two respiratory support modes or subsystems may be facilitated by a structure of the gas delivery conduit 14 which supplies the oral interface 200 and/or the nasal conduit 1012 which supplies the nasal cannula 1010. Such a structure may comprise a portion 204 configured from a first condition in which a first level of gases is able to pass through the portion 204 to a second condition in which a second level of gases is able to pass through the portion 204. Preferably, the portion 204 is configured to be more collapsible or otherwise better adapted at changing the flow of gas through the portion 204 (therefore reducing the flow of gas through the respective conduit and to the patient) than other portions of the gas delivery conduit 14 and/or the nasal conduit 1012. In some examples, the first condition of the portion 204 is a substantially open condition and the second condition is a substantially closed condition. That is, the gas delivery conduit 14 and or the nasal conduit 1012 is configured to be more collapsible, deformable or otherwise adapted to fully close off the flow at the portion 204 than at other portions of the conduit 14 and/or conduit 1012. [0216] Figure 30 shows one example, in which a conduit (for example the gas delivery conduit 14 of Figure 29) at portion 204 is substantially closed by the seal 304 of face mask 302. In such an embodiment, the portion 204 (i.e. the more collapsible or deformable section) of the gas delivery conduit 14 which is collapsible should be of a length that is greater than a width of a section of a seal of the face mask that bears over the portion 204 of the gas delivery conduit 14. This ensures the seal of the face mask does not bear over a non-collapsible section of the gas delivery conduit 14. For example, the portion 204 may extend from a distance of 35mm or less from the centre of a user's nose to at least 50mm from the centre of a user's nose, the portion 204 having a length of at least 15mm. In some embodiments the length of the portion 204 may be at least 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, 50mm or greater. [0217] The portion 204 may progress between the first and second conditions based on a relative level of force applied to an external wall, or experienced by an internal wall, of the portion 204. For example, as shown in Figure 29, the force may be applied by the seal 304 of face mask 302. In this example, portion 204 is configured to be positioned under the seal 304 of the face mask 302. Alternatively, the force may be applied to portion 204 by other means, e.g., clamps (not shown). In some embodiments, the seal of the face mask acting on the portion 204 of the gas delivery conduit causes the portion 204 to form a seal or at least a partial seal between the oral interface 200 (with or without nasal cannula 1010) and the flow generator. Additionally, the seal of the face mask forms a seal or at least a partial seal over the portion 204 of the gas delivery conduit 14 and/or nasal conduit 1012. Switching between respiratory support therapies is therefore achieved simply by applying a mask to the patient's face so that the seal of the mask collapses (partially or completely) the portion 204 of the of the gas delivery conduit 14 to 'turn off' or reduce the therapy supplied by the oral interface 200 (with or without nasal interface 1010) and also provides a seal between face mask 300 and the external surface of the portion 204 such that therapy can be provided exclusively or at least predominantly by the mask. In some embodiments the removal of the mask from the patient's face allows the therapy supplied by the first interface to recommence. Figures 31 to 34 are examples of a patient assembly having an oral interface 200 and a nasal cannula 1010, and demonstrating schematically placement of a portion 204 which may be configured to transition between conditions (e.g. substantially collapsible) to alter the flow of gas in order to facilitate switching between two respiratory support modes or subsystems as described above. [0218] The portion 204 of a conduit that is configured to transition or substantially collapse may be due to the cross-sectional shape. That is, the portion may contain predefined thinned regions that aid in the conduit portion 204 transitioning or collapsing easily. In other examples, the portion 204 may be thinner in cross-section compared to the rest of the conduit it is in fluid communication with. [0219] In Figure 31 the nasal interface 1010 and the oral interface 200 may receive a gases flow from a common flow source 12. Nasal interface 1010 may be supplied by a nasal conduit 1012 which has a portion 204 and oral interface 200 may be supplied by a gas delivery conduit 14 which has a separate portion 204, each of which are able to transition between a first (substantially open) condition, and a second (substantially closed) condition to achieve substantial cessation of flow to their respective interfaces when sufficient pressure is applied. The portions 204 may be located on the conduits 1012 and 14 such that when in use, they the portions are beneath the cuff of a face mask when applied over the patient interface assembly. This need not be the case however, and the mask cuff may be applied over only one of the portions 204 with clamp, hand or other means used to apply sufficient pressure to the other portion 204. [0220] In Figures 32 and 33, the nasal interface 1010 is fluidly connected to the oral interface 200 at the base of the nasal interface 1010 via the interface connector 1110 to form a patient interface assembly as in Figures 25 to 27. The gas flow may be received from a common flow source 12 via gas delivery conduit 14 which flows first into the nasal interface 1010 and then into the oral interface 200 as in Figure 32. Alternatively, the gas flow may be received from a common flow source 12 via a gas delivery conduit 14 which flows first into the oral interface 200 and then into the nasal interface 1010 as in Figure 33. The gas delivery conduit 14 has a portion 204, which is able to transition between a first (substantially open) condition, and a second (substantially closed) condition to achieve substantial cessation of flow to the patient interface assembly when sufficient pressure is In either case, the portion 204 may be located on the conduit 14 such that when in use, the portion is beneath the cuff of a face mask when applied over the patient interface assembly. This need not be the case however, and a clamp, hand or other means used to apply sufficient pressure to the portion 204. The arrangement in Figures 32 and 33 may be advantageous because a single portion 204 may be utilised to switch between respiratory support provided via the oral and nasal parts of the patient interface assembly in a first respiratory support mode and e.g. a face mask in a second respiratory support mode. [0221] In Figure 34, the nasal interface 1010 and the oral interface 200 receive separate flows of gas from separate flow sources 12a and 12b. Nasal conduit 1012 and the gas delivery conduit 14 may each have a portion 204 which is able to transition between a first (substantially open) condition, and a second (substantially closed) condition to achieve substantial cessation of flow to the patient interface assembly when sufficient pressure is applied. The portions 204 may be located on the gas delivery conduit 14 and the nasal conduit 1012 such that when in use, the portions 204 are beneath the cuff of a face mask when applied over the patient interface assembly. This need not be the case however, and a clamp, hand or other means used to apply sufficient pressure to one or both of the portions 204. [0222] In some examples, switching(e.g. cessation or reduction of flow from a flow source 12, 12a, 12b) may be carried out electronically with the direction from a controller 19 which may comprise a microcontroller. For example, the condition where the face mask 300 is placed over the oral interface 200 and optional nasal interface 1010 may be detected by one or more sensors 18a, 18b, 18c, 18d. For example, the one or more sensors may be a pressure sensor. The one or more sensors may detect a rise in pressure in the conduit 14 which upon electronic communication with a controller 19 causes a signal to be sent to the flow source 12 to reduce or stop flows to the interface 200. [0223] High flow respiratory support delivered orally may increase mean airway pressure by 3-5 cmH2O per 100 L/min supplied flow, with or without independently providing high flow respiratory support delivered nasally. This may be applicable in both jaw-thrust and non-jaw- thrust airways, and with or without breathing. [0224] In some examples, using an unsealed nasal cannula interface 1010 by itself may provide 0.18 cmH2O static pressure when the flow rate is about 70 L/min. In some examples, using an oral interface 200 by itself may provide 0.8 cmH2O static pressure when the flow rate is 70 L/min. However, simulations (e.g. bench testing on a rigid airway model with jaw-thrust) indicate that using a nasal interface 1010 to a flow rate of 70L/min and simultaneously using an oral interface 200 to produce a flow rate of 70L/min may provide 1.4 cmH2O static pressure. [0225] Similarly, in some examples, using an unsealed nasal cannula interface 1010 by itself may provide about 0.5 cmH2O static pressure when the flow rate is 100 L/min. In some examples, using an oral interface 200 by itself may provide about 2 cmH2O static pressure when the flow rate is 100 L/min. However, simulations (e.g. bench testing on a rigid airway model with jaw-thrust) indicate that using a nasal interface 1010 to produce a flow rate of 100L/min and simultaneously using an oral interface 200 to produce a flow rate of 100L/min may provide about 4 cmH2O static pressure. [0226] Thus, there may be a synergistic benefit associated with concurrent use of both nasal and oral interfaces to deliver high flows of gases. A synergistic benefit may arise when pressures generated within the patient are higher when using a nasal and oral interface simultaneously than when using them separately. For example, using a nasal interface with no oral interface may generate x cmH2O of flows and using an oral interface with no nasal interface may generate y cmH2O of flow. Using the nasal interface and the oral interface 200 simultaneously may generate pressures greater than or equal to the sum of x and y cmH2O. This is because the patient experiences a higher resistance to flow with both nasal and oral interfaces in place. The increase in resistance to flow may be the contribution of jet flows colliding with the patient’s breath and/or the increased structural occlusion provided by the patient interfaces in the airways. The jet flows may be from the oral interface 200 or nasal interface 1010 or both oral interface 200 and nasal interface 1010. [0227] The pressure generated by using the nasal interface and the oral interface 200 simultaneously may generate pressures between 0cmH2O and 20cmH20. More specifically, the pressures generated may be between 0.1cmH2O to 10cmH20. [0228] It is to be understood that a system for providing respiratory support to the patient 16 using a patient interface assembly 15 according to the embodiments disclosed herein may include at least one flow source 12 for generating a gases flow 13, and optionally at least one humidifier 17 for humidifying and/or warming the gases flow for delivery of humidified gases flow to the patient 16. [0229] Applications of the oral interface 200 may include anaesthetic procedures or procedures involving sedation of the patient 16 the patient 16 is spontaneously or non- spontaneously breathing, and access to their oral cavity is required. The oral interface 200 may be particularly useful in OSA (Obstructive Sleep Apnoea) patients having a higher risk of upper airway collapse or high BMI (Body Mass Index) patients who may have higher risk of atelectasis. The oral interface 200 may also provide improved airway clearance and/or increase the patient’s FiO2 (fraction of inspired oxygen), which would be useful in at least the preoxygenation stage. This may also be useful in procedures where the patient 16 is apnoeic and required to be still, e.g., diagnostic and/or interventional radiology imaging, to allow for better scans. [0230] The oral interface 200 through the channel 280 may be configured to allow contemporaneous use of other medical instruments/device to access the patient’s mouth, e.g., for shared airway procedures, while also providing for delivery of gases. The oral interface 200 can also augment respiratory support or therapy provided by the nasal interface 1010 (low or high flow). Advantageously, the gases flow may be delivered substantially annularly or circumferentially around the inner wall portion 242 of the body 240 in an end face of the body portion toward the second end opening 270. This may make the gases flow less susceptible to disruption or blockage during a procedure e.g. due to positioning of the clinician’s hands and/or instruments in the channel 280. Depending on the location of the at least one gases outlet 220, the body 240 towards the first end opening 260 may provide further protection, shielding the gases outlet 220 from becoming blocked. In particular, part of the inner wall portion 242 where the gases outlet 220 is formed may shield the gases outlet 220 from blockages. [0231] The oral interface 200 may be used to control airway pressure while maintaining an unsealed airway, thereby allowing for provision of therapy modes like non-invasive ventilation (NIV), or a basic periodic pressure change to create small tidal flows of gas into and out of otherwise-apnoeic lungs, all without losing shared-airway access. [0232] This specification, including the claims, is intended to be interpreted as follows: [0233] Embodiments or examples described in the specification are intended to be illustrative of the invention, without limiting the scope thereof. The invention is capable of being practised with various modifications and additions as will readily occur to those skilled in the art. Accordingly, it is to be understood that the scope of the invention is not to be limited to the exact construction and operation described or illustrated, but only by the following claims. It is to be understood that the terms “embodiment” and “example” do not supersede the following claims. [0234] The mere disclosure of a method step or product element in the specification should not be construed as being essential to the herein, except where it is either expressly stated to be so or expressly recited in a claim. [0235] The terms in the claims have the broadest scope of meaning they would have been given by a person of ordinary skill in the art as of the relevant date. [0236] The terms “a” and “an” mean “one or more”, unless expressly specified otherwise. [0237] Neither the title nor the abstract of the present application is to be taken as limiting in any way as the scope of the claimed invention. [0238] Where the preamble of a claim recites a purpose, benefit or possible use of the claimed invention, it does not limit the claimed invention to having only that purpose, benefit or possible use. [0239] It should be noted that terms of degree such as “generally”, “substantially”, “about” and “approximately” as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. These terms of degree should be construed as including a deviation of the modified term if this deviation would not negate the meaning of the term it modifies. [0240] In this specification including the claims the term “circumferential” and variants of that term such as “circumference” and “circumferentially” are used to refer to the enclosing boundary of a closed geometric shape that includes but is not limited to a circle. [0241] In the specification, including the claims, the term “comprise”, and variants of that term such as “comprises” or “comprising”, are used to mean “including but not limited to”, unless expressly specified otherwise, or unless in the context or usage an exclusive interpretation of the term is required. [0242] Furthermore, the recitation of any numerical ranges by endpoints herein includes all numbers and fractions subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.90, 4, and 5). It is also to be understood that all numbers and fractions thereof are presumed to be modified by the term “about” which means a variation up to a certain amount of the number to which reference is being made if the end result is not significantly changed. [0243] As used herein, the wording “and/or” is intended to represent an inclusive- or. That is, “X and/or Y” is intended to mean X or Y or example. As a further example, “X, Y, and/or Z” is intended to mean X or Y or Z or any combination thereof. [0244] The disclosure of any document referred to herein is incorporated by reference into this patent application as part of the present disclosure, but only for purposes of written description and enablement and should in no way be used to limit, define, or otherwise construe any term of the present application where the present application, without such incorporation by reference, would not have failed to provide an ascertainable meaning. Any incorporation by reference does not, in and of itself, constitute any endorsement or ratification of any statement, opinion or argument contained in any incorporated document.

Claims

The claims defining the invention are as follows: 1. An oral interface for providing respiratory support to a patient, the oral interface comprising: at least one gases inlet for receiving a gases flow; at least one gases outlet for providing the gases flow to the patient; a gases flow path defined between the at least one gases inlet and the at least one gases outlet; and a body comprising: a mouth-engaging portion configured to engage with a mouth of the patient; a first end opening and a second end opening disposed on opposite sides of the body, the first end opening and the second end opening defining a channel for providing access into the mouth; wherein the at least one gases outlet comprises a restriction configured to increase an average velocity of the gases flow upon exiting the at least one gases outlet.

2. The oral interface of claim 1, wherein the at least one gases outlet is disposed at any one of: at or proximal to the first end opening, between the first end opening and the second end opening, or at or proximal to the second end opening.

3. The oral interface of claim 1 or 2, wherein the at least one gases outlet comprises the restriction, and wherein the restriction comprises a nozzle configured to provide a jet flow of the gases flow.

4. The oral interface of any one of claims 1 to 3, wherein at least part of the gases flow path is circumferential around the channel.

5. The oral interface of any one of claims 1 to 4, wherein the at least one gases outlet is disposed along a perimeter of the channel.

6. The oral interface of any one of claims 1 to 5, wherein the average velocity of the gases flow is substantially uniform around the channel.

7. The oral interface of claim 6, wherein a width of the at least one gases outlet is substantially uniform around the channel.

8. The oral interface of any one of claims 1 to 7, wherein the at least one gases outlet is configured to direct the gases flow in a parallel to an axis of the body extending between the first end opening and the second end opening.

9. The oral interface of any one of claims 1 to 7, wherein the at least one gases outlet is configured to direct the gases flow to converge from the first end opening towards the second end opening based on one or both of an angle of the restriction and a cross- sectional width of the gases flow path.

10. The oral interface of any one of claims 1 to 7, wherein the at least one gases outlet is configured to direct the gases flow to converge towards a line proximal to the second end opening.

11. The oral interface of claim 10, wherein the line is substantially orthogonal to the axis of the body extending between the first end opening and the second end opening.

12. The oral interface of any one of claims 1 to 7, wherein the at least one gases outlet is configured to direct the gases flow to converge towards a point proximal to the second end opening.

13. The oral interface of claim 12, wherein a location of the point is determined according to one or more of an angle of the restriction, an angle of the at least one gases outlet, shape of the at least one gases outlet, a cross-sectional width of the gases flow path, shape of the at least one gases inlet, and average velocity of the gases flow.

14. The oral interface of any one of claims 1 to 13, wherein the at least one gases outlet is configured to provide the gases flow such that airway pressure of the patient is at least about 0.1 cmH2O.

15. The oral interface of any one of claims 1 to 14, wherein the at least one gases outlet is configured to provide the gases flow such that airway pressure of the patient is between about 0.1 cmH2O and about 10 cmH2O.

16. The oral interface of any one of claims 1 to 15, wherein the gases flow has a flow rate of between about 0 LPM and about 200 LPM.

17. The oral interface of any one of claims 1 to the gases flow has a flow rate of between about 20 LPM and about 200 LPM.

18. The oral interface of any one of claims 1 to 17, wherein the average velocity of the gases flow is about 100m/sec.

19. The oral interface of any one of claims 1 to 18, wherein the body has a cross-section with a first dimension and a second dimension perpendicular to the first dimension, wherein the first dimension is greater than the second dimension.

20. The oral interface of any one of claims 1 to 19, wherein at least part of the body has an elliptical, obround, circle, oval or other cross-sectional shape transverse to an axis extending from the first end opening to the second end opening.

21. The oral interface of any one of claims 1 to 20, wherein a cross-sectional width of the gases flow path is non-uniform around the channel and/or a width of the at least one gases outlet is non-uniform around the channel.

22. The oral interface of any one of claims 1 to 21, wherein the at least one gases outlet comprises two or more gases outlets disposed around the channel.

23. The oral interface of any one of claims 1 to 22, wherein the at least one gases inlet comprises a first gases inlet and a second gases inlet.

24. The oral interface of claim 23, wherein the first gases inlet has a cross-sectional area substantially equal to a cross-sectional area of the second gases inlet.

25. The oral interface of claim 23 or 24, wherein one of the first gases inlet and the second gases inlet is disposed to be proximal to a nose of the patient when in use.

26. The oral interface of any one of claims 23 to 25, wherein the first gases inlet and the second gases inlet are disposed opposite to each other.

27. The oral interface of ant one of claims 1 to 26, further comprising a cover disposed around the mouth-engaging portion of the body.

28. The oral interface of claim 27, wherein the cover is disposed around a section of the mouth- engaging portion that is configured to be inside the mouth of the patient and configured to provide a substantial seal around the oral interface and the mouth of the patient such that fluid access to the mouth of the patient is substantially via the channel.

29. The oral interface of any one of claims 1 to 28, further comprising headgear connectors configured to removably connect with a headgear wearable by the patient to stabilize the oral interface during use.

30. An oral interface for providing respiratory support to a patient, the oral interface comprising: at least one gases inlet for receiving a gases flow; at least one gases outlet for providing the gases flow towards the back of a mouth of the patient; a gases flow path defined between the at least one gases inlet and the at least one gases outlet; and a body comprising: a first end opening and a second end opening disposed on opposite sides of the body, the first end opening and the second end opening defining a channel for providing access into the mouth of the patient, wherein the at least one gases outlet is disposed circumferentially around the channel and configured to provide the gases flow as a jet flow towards the back of the mouth of the patient.

31. The oral interface of claim 30, wherein the at least one gases outlet is disposed at any one of the following locations: at or proximal the first end opening, between the first end opening and the second end opening, or at or proximal the second end opening.

32. The oral interface of claim 30 or 31, wherein the at least one gases outlet is configured to provide the gases flow as the jet flow into the channel.

33. The oral interface of claim any one of claims 30 to 32, wherein the at least one gases outlet comprises a nozzle configured to provide the jet flow.

34. The oral interface of any one of claims 30 wherein the at least one gases outlet is disposed along a perimeter of the channel.

35. The oral interface of any one of claims 30 to 34, wherein the at least one gases outlet comprises a circumferential slit provided around the perimeter of the body defining around the gases flow path.

36. The oral interface of any one of claims 30 to 35, wherein the at least one gases outlet is further configured to direct the gases flow in a direction substantially parallel to an axis of the body extending between the first end opening and the second end opening.

37. The oral interface of any one of claims 30 to 35, wherein the at least one gases outlet is further configured to direct the gases flow to converge from the first opening towards the second end opening based on one or both more of an angle of the restriction, an angle of the at least one gas outlet, shape of the at least one gas outlet and a cross-sectional width of the gases flow path.

38. The oral interface of any one of claims 30 to 35, wherein the at least one gases outlet is configured to direct the gases flow to converge towards a line proximal to the second end opening.

39. The oral interface of claim 38, wherein the line is substantially parallel orthogonal to the axis of the body extending between the first end opening and the second end opening.

40. The oral interface of any one of claims 30 to 35, wherein the at least one gases outlet is configured to direct the gases flow to converge towards a point proximal to the second end opening.

41. The oral interface of claim 40, wherein a location of the point is based on one or more of an angle of the restriction, an angle of the at least one gas outlet, shape of the at least one gas outlet, a cross-sectional width of the gases flow path, shape of the at least one gases inlet, average velocity of the gases flow.

42. The oral interface of any one of claims 30 to 41, wherein the at least one gases outlet is configured to direct the gases flow towards the second end opening.

43. The oral interface of any one of claims 30 to 42, wherein the average velocity of the gases flow proximal to the at least one gases outlet is substantially uniform around the channel.

44. The oral interface of any one of claims 30 to 43, wherein the at least one gases outlet is configured to provide the gases flow such that airway pressure of the patient is at least about 0.1 cmH2O.

45. The oral interface of any one of claims 30 to 44, wherein the at least one gases outlet is configured to provide the gases flow such that airway pressure of the patient is between about 0.1 cmH2O and about 10 cmH2O.

46. The oral interface of any one of claims 30 to 45, wherein the gases flow has a flow rate of between about 0 LPM and about 200 LPM.

47. The oral interface of any one of claims 30 to 46, wherein the gases flow has a flow rate of between about 20 LPM and about 200 LPM.

48. The oral interface of any one of claims 30 to 47, wherein the average velocity of the gases flow is about 100 m/sec.

49. The oral interface of any one of claims 30 to 48, wherein the body has a cross-section with a first dimension and a second dimension perpendicular to the first dimension, wherein the first dimension is greater than the second dimension.

50. The oral interface of any one of claims 30 to 49, wherein at least part of the body has an elliptical or obround, circle, oval or other cross-sectional shape cross-section transverse to an axis extending from the first end opening to the second end opening.

51. The oral interface of any one of claims 30 to 50, wherein a cross-sectional width of the gases flow path is non-uniform around the channel.

52. The oral interface of any one of claims 30 to 51, wherein the at least one gases outlet comprises two or more gases outlets disposed around the channel.

53. The oral interface of any one of claims 30 wherein the at least one gases inlet comprises a first gases inlet and a second gases inlet.

54. The oral interface of claim 53, wherein the first gases inlet has a cross-sectional area substantially equal to a cross-sectional area of the second gases inlet.

55. The oral interface of any one of claim 53 or 54, wherein one of the first gases inlet and the second gases inlet is disposed to be proximal to a nose of the patient when in use.

56. The oral interface of any one of claims 54 to 55, wherein the first gases inlet and the second gases inlet are disposed opposite to each other.

57. The oral interface of any one of claims 30 to 56, further comprising a cover disposed around the body.

58. The oral interface of claim 57, wherein the cover is disposed around a section of the body that is configured to be inside the mouth of the patient and further configured to provide a substantial seal between the mouth-engaging portion and teeth and/or lips of the patient.

59. The oral interface of any one of claims 30 to 58, further comprising one or more headgear connectors configured to removably connect with a headgear wearable by the patient to stabilize the oral interface during use.

60. An oral interface for providing respiratory support to a patient, the oral interface comprising: at least one gases inlet for receiving a gases flow; at least one gases outlet for providing the gases flow to the patient; a gases flow path defined between the at least one gases inlet and the at least one gases outlet; and a body comprising: a first end opening and a second end opening disposed on opposite sides of the body, the first end opening and the second end opening defining a channel for providing access into a mouth of the patient; wherein the at least one gases outlet is configured such that an average velocity of the gases flow exiting the at least one gases outlet is up to about 110m/s.

61. The oral interface of claim 60, wherein the average velocity of the gases flow exiting the at least one gases outlet is between about 10m/s and about 110m/s.

62. The oral interface of claim 60 or 61, wherein the average velocity of the gases flow exiting the at least one gases outlet is between about 40m/s and about 110m/s.

63. The oral interface of any one of claims 60 to 62, wherein the average velocity of the gases flow is about 100m/sec.

64. The oral interface of any one of claims 60 to 63, wherein the gases flow path is extends circumferentially around at least part of the channel.

65. The oral interface of any one of claims 60 to 64, wherein the at least one gases outlet is disposed around a perimeter of the channel.

66. The oral interface of any one of claims 60 to 65, wherein the average velocity of the gases flow is substantially uniform around the channel.

67. The oral interface of any one of claims 60 to 66, wherein a width of the at least one gases outlet is substantially uniform around the channel.

68. The oral interface of any one of claims 60 to 67, wherein the at least one gases outlet is configured to direct the gases flow in a direction substantially parallel to an axis of the body extending between the first end opening and the second end opening.

69. The oral interface of any one of claims 60 to 67, wherein the at least one gases outlet is configured to direct the gases flow to converge from the first end opening towards the second end opening based on one or both of an angle of the restriction and a cross-sectional width of the gases flow path.

70. The oral interface of any one of claims 60 to 67, wherein the at least one gases outlet is configured to direct the gases flow to converge towards a line proximal to the second end opening.

71. The oral interface of claim 70, wherein the line is substantially parallel orthogonal to the axis of the body extending between the first end opening and the second end opening.

72. The oral interface of any one of claims 60 to 67, wherein the at least one gases outlet is configured to direct the gases flow to converge towards a point proximal to the second end opening.

73. The oral interface of claim 72, wherein a location of the point inside the channel is based on one or more of an angle of the restriction, an angle of the at least one gas outlet, shape of the at least one gas outlet, a cross-sectional width of the gases flow path, shape of the at least one gases inlet, average velocity of the gases flow.

74. The oral interface of any one of claims 60 to 73, wherein the at least one gases outlet is configured to provide the gases flow such that airway pressure of the patient is at least about 0.1 cmH2O.

75. The oral interface of any one of claims 60 to 74, wherein the at least one gases outlet is configured to provide the gases flow such that airway pressure of the patient is between about 0.1 cmH2O and about 10 cmH2O.

76. The oral interface of any one of claims 60 to 75, wherein the gases flow has a flow rate of between about 0LPM and about 200LPM.

77. The oral interface of any one of claims 60 to 76, wherein the gases flow has a flow rate of between about 20LPM and about 200LPM.

78. The oral interface of any one of claims 60 to 77, wherein the body has a cross- section with a first dimension and a second dimension perpendicular to the first dimension, wherein the first dimension is greater than the second dimension.

79. The oral interface of any one of claims 60 to 78, wherein at least part of the body has an elliptical or obround circle, oval or other cross-sectional shape cross-section transverse to an axis extending from the first end opening to the second end opening.

80. The oral interface of any one of claims 60 wherein a cross-sectional width of the gases flow path is non-uniform around the channel, and/or wherein a width of the at least one gases outlet may be non-uniform around the channel.

81. The oral interface of any one of claims 60 to 80, wherein the at least one gases outlet comprises two or more gases outlets disposed around the channel.

82. The oral interface of any one of claims 60 to 81, wherein the at least one gases inlet comprises a first gases inlet and a second gases inlet.

83. The oral interface of claim 82, wherein the first gases inlet has a cross-sectional area substantially equal to a cross-sectional area of the second gases inlet.

84. The oral interface of claim 82 or 83, wherein one of the first gases inlet or the second gases inlet is disposed to be proximal to a nose of the patient when in use.

85. The oral interface of any one of claims 82 to 84, wherein the first gases inlet and the second gases inlet are disposed opposite to each other.

86. A patient interface assembly comprising: a nasal interface; and an oral interface according to any one of claims 1 to 85.

87. The patient interface assembly of claim 86, wherein the nasal interface and the oral interface are configured to receive the gases flow from a common flow source.

88. The patient interface assembly of claim 86, wherein the nasal interface and the oral interface are configured to receive the gases flow from separate flow sources.

89. The patient interface assembly of any one of claims 86 to 88, wherein the nasal interface provides a first gases flow to the patient at a first flow rate and the oral interface provides a second gases flow to the patient at a second flow rate.

90. The patient interface assembly of claim 89, wherein the first flow rate is different to the second flow rate.

91. The patient interface assembly of claim 89 90, wherein the first flow rate and the second flow rate are between about 0LPM to about 100LPM.

92. The patient interface assembly of any one of claims 89 to 91, wherein the first flow rate and the second flow rate are between about 20LPM to about 100LPM.

93. The patient interface assembly of claim 92, wherein a sum of the first flow rate and the second flow is between about 0LPM and about 200LPM.

94. The patient interface assembly of any one of claims 86 to 93, wherein the nasal interface and the oral interface are fluidly connected.

95. The patient interface assembly of any one of claims 86 to 94, wherein a base of the nasal interface comprises an interface connector to allow fluid communication with the gases flow path in the oral interface.

96. The patient interface assembly of any one of claims 86 to 95, wherein the nasal interface comprises a nasal cannula.

97. The patient interface assembly of claim 96, wherein the nasal cannula is non- sealing.

98. A system for providing respiratory support to a patient, the system comprising: at least one flow source for generating a gases flow; at least one humidifier configured to humidify the gases flow for delivery of a humidified gases flow to a patient interface; and the patient interface assembly according to any one of claims 1 to 97.

99. A system for providing respiratory support to a patient, the system comprising: at least one flow source for generating a gases flow; and the patient interface according to any one of claims 1 to 85 or the patient interface assembly according to any one of claims 86 to 97.