Patent Description:
This invention relates to a respiratory assistance apparatus adapted to deliver respiratory gases to a user or patient. More particularly, the invention relates to a respiratory assistance apparatus provided with a disinfection mode and a method of disinfecting a respiratory assistance apparatus using a disinfection mode.

A respiratory assistance apparatus typically comprises a humidifier, a gases inlet to supply a gases flow from a gases source to the humidifier, and a patient outlet to deliver a gases flow from the humidifier to the user or patient. The gases source can be a blower, fan, pressurised tank, compressor, or the like. An inspiratory tube can be connected between the patient outlet and a patient interface that is arranged to be mounted at or on the face of the user or patient. The patient interface may comprise a full face mask, nasal mask, nasal cannula, oral mouthpiece, or tracheostomy fitting.

One form of respiratory assistance apparatus can comprise an integrated system, where the gases source and the humidifier are contained within the same housing. With an integrated system, the patient outlet is typically mounted on the housing, and the humidifier and the patient outlet are typically connected via an intermediate passageway located at least partially within the housing.

Such respiratory assistance apparatus may be used in hospitals, other healthcare organisations, and care homes for example. They may also be used at the home of a user or patient. It is a problem in any such environment to keep a respiratory assistance apparatus clean and free from potentially harmful bacteria. It is often desirable that at least some components of the apparatus can be reused with subsequent users or patients, rather than requiring a new apparatus for each user or patient. In such circumstances, it is important that the apparatus can be cleaned to a sufficiently high standard for safe reuse. In particular, it may be required that some components of the apparatus can be disinfected, even if other components, such as the inspiratory tube and the patient interface, are to be replaced.

It is not usually required to disinfect components that are in the gases flow path up to the chamber inlet, because the gases that contact such components are typically relatively dry external air or oxygen. However, it is often necessary to clean the components in the subsequent gases flow path that are subjected to moisture, because moisture is susceptible to carrying bacteria which can cause the establishment and growth of biofilms that can be transmitted to the patient. Whilst some components are accessible and therefore can be relatively easily cleaned (e.g., some patient interfaces may be placed in a dishwasher), other components are contained within the housing, or may have internal features that are difficult to access, and thus are not easily cleaned. One example of such a component is the aforementioned intermediate passageway that links the humidifier to the patient outlet. In some cases, components cannot easily be removed from the apparatus for cleaning, or at least not without specialist or relatively skilled personnel. Removal of components also introduces a risk of damage to the components or the apparatus, or of incorrect refitting of the components after cleaning.

<CIT> discloses a breathing assistance apparatus that has a convenient and effective method of cleaning internal conduits inside the apparatus. The breathing assistance apparatus is preferably a gases supply and humidification device. The cleaning method is a method of disinfection that is automated so minimal training is required to disinfect in particular an internal elbow conduit within the device. It is therefore not necessary to dismantle the gases supply and humidification device, therefore, inadvertent damage to the internal parts of the device is avoided. The present invention also provides a method of disinfecting a heated breathing conduit and a patient interface.

<CIT> discloses a high flow therapy system including a microprocessor, a heating element a non-sealing respiratory interface and a sensor is disclosed. The heating element is disposed in electrical communication with the microprocessor and is capable of heating a liquid to create a gas. The non-sealing respiratory interface is configured to deliver the gas to a patient. The sensor is disposed in electrical communication with the microprocessor and is configured to measure pressure in an upper airway of the patient.

<CIT> discloses an apparatus for transnasal inspiration with heated and humidified gas, including a preheating stage with high temperature overshoots used to destroy pathogens, and a switch-off mode serving to dry the nasal cannula.

<CIT> discloses a humidifying and heating apparatus for respiratory gas. A humidifying vessel of the apparatus can be sterilized in a steam sterilizer.

It is therefore an object of the invention to provide a respiratory assistance apparatus, and a method of disinfecting a respiratory assistance apparatus, which overcomes or at least ameliorates one or more of the disadvantages of the prior art, or alternatively at least provides the public or industry with a useful choice.

According to the present invention there is provided a respiratory assistance apparatus according to claim <NUM> and a method according to claim <NUM>. Preferred aspects are set out in the dependent claims.

Further objects of the disclosure, which need not form part of the invention as claimed but may contain features present in embodiments of the invention as claimed, will become apparent from the following description.

Accordingly, in one aspect there is described a respiratory assistance apparatus adapted to deliver a gases flow to a user or patient, comprising a housing provided with a chamber and a heater, the chamber comprising at least one chamber port connected to, or arranged to be connected to, at least one intermediate passageway, the apparatus being operative according to a disinfection mode of predetermined profile in which the heater heats a liquid in the chamber to produce vapour at or above a setpoint temperature, namely a target dewpoint temperature, the apparatus being arranged such that the vapour is delivered to the intermediate passageway to disinfect the intermediate passageway with moist heat, the vapour at or above the target dewpoint temperature continuing to be delivered to the intermediate passageway throughout the predetermined duration of the disinfection mode.

The predetermined profile may include a combination of some or all of duration, temperature, moisture and pressure.

The at least one chamber port may comprise a chamber inlet port and a chamber outlet port, the chamber inlet port being arranged to be in fluid communication in use with a gases source in the housing. The gases source may comprise a blower, fan or compressor arranged to deliver a gases flow through the chamber inlet port and into the chamber. Such arrangements are not essential due to the expansion of the heated water but are preferred to prevent steam being delivered to other components of the apparatus via the chamber inlet port. Such components may be susceptible to damage if subjected to steam or chemical vapours from disinfection. Alternatively, a valve could be used to prevent an undesirable flow of vapour, directing such flow of vapour through the chamber outlet port.

The chamber comprises part of a humidifier of the apparatus, the humidifier being arranged to humidify the gases flow prior to delivery of the gases flow to the user or patient when the apparatus is operating in a non-disinfection mode. The liquid used during the disinfection mode is water.

The chamber may be removably mounted on the apparatus. The chamber may be reusable or disposable.

The chamber may comprise an identifier, the apparatus being operative to detect the identifier and thus the presence of the chamber. The identifier may comprise a chamber inlet port arranged to have a high flow resistance which can be detected by the apparatus to identify the presence of the chamber. The high flow resistance also prevents vapour undesirably passing through the chamber inlet port into the housing, by causing local high flow velocity at the chamber inlet port when a gases flow is delivered through the chamber inlet port from the housing.

The intermediate passageway may comprise an internal passageway located at least partially within the housing. The intermediate passageway may comprise a conduit or elbow.

The intermediate passageway preferably directly or indirectly connects a gases inlet that allows a gases flow into the housing with a patient outlet that delivers a gases flow to the user or patient.

One end of the intermediate passageway may comprise the patient outlet.

In one example, during the disinfection mode, the end of the intermediate passageway comprising the patient outlet is connected to the chamber outlet port via a removable disinfection tube which delivers vapour or steam to the intermediate passageway. The disinfection tube may be heated. In this example, the at least one port of the chamber is connected to the at least one intermediate passageway, by way of a temporary connection, that is, a connection used specifically for cleaning or disinfection.

In another example, the chamber outlet port is directly connected to the intermediate passageway at an opposed end from the patient outlet. In this example, the at least one port of the chamber is connected to the at least one intermediate passageway by way of a permanent connection, that is, a connection that remains after termination of the disinfection mode.

The intermediate passageway may comprise an elbow having opposed ends linked by an intermediate bent portion. In one example, the bent portion is bent through <NUM>°.

The intermediate passageway may be provided with at least one sensor operative to generate a signal indicative of, for example, flow rate, moisture content or temperature at or proximate to the intermediate passageway.

A cap may be provided comprising an engaging formation arranged to engage with one end of the intermediate passageway to mount the cap on said end, the cap comprising a flow restrictor arranged to restrict flow of fluid through the intermediate passageway when the cap is so mounted, to provide back pressure in the intermediate passageway during the disinfection mode. Additionally or alternatively, the cap may comprise an antibacterial filter. The cap may comprise an identifier. Non-limiting examples of a suitable identifier include a magnet, an RFID tag, or a source of electrical resistance such as a resistor.

The apparatus is operative to heat the liquid to produce vapour at or above a target dewpoint temperature, that is, a fixed dewpoint temperature determined prior to initiation of the disinfection mode. Preferably, the target dewpoint temperature is a minimum dewpoint temperature required for effective disinfection by moist heat.

The apparatus may be operative to heat the liquid to produce vapour at or above a dewpoint temperature selected by a clinician or user, that is, a variable dewpoint temperature determined before or after initiation of the disinfection mode.

The target dewpoint temperature may be greater than <NUM>, is preferably greater than <NUM>, and is most preferably greater than <NUM>. The presence of moist heat in the gases flow enables the target dewpoint temperature to be substantially reduced as compared to target temperatures of prior methods using dry or non-humidified air.

Note, in this and other aspects of the disclosure, that the target dewpoint temperature may be set and measured within the chamber (e.g., at the chamber outlet port) and/or within the intermediate passageway and/or subsequent thereto. The target dewpoint temperature may require adjustment depending on where it is measured to ensure adequate disinfection efficacy.

Further, the target dewpoint temperature may be defined by a dewpoint temperature range.

Yet further, the target dewpoint temperature may be varied within the disinfection cycle. For example, in one example disinfection cycle, the target dewpoint temperature may generally be relatively low, say around <NUM>, and increased for a short portion of the cycle to say <NUM>, potentially reducing the time required for disinfection and/or better ensuring adequate disinfection efficacy.

The apparatus may be operative to control the duration of the disinfection mode in dependence upon the target and/or a measured dewpoint temperature. The apparatus may be operative to control the duration of the disinfection mode by reference to a lookup table, an algorithm or a formula relating the duration of the disinfection mode to a range of target and/or measured dewpoint temperatures.

In addition to reducing the temperature required for disinfection, the use of vapour in the gases flow can also reduce the length of time required for disinfection. For example, <NUM> to <NUM> minutes may suffice, preferably around <NUM> minutes.

Preferably, the apparatus comprises a chamber sensor operative to generate a signal indicative of whether the chamber is mounted on the apparatus. The chamber sensor may be operative to generate a signal indicative of whether a specific chamber is mounted on the apparatus. The chamber sensor may comprise the combination of a pressure/flow sensor and a flow restriction on the specific chamber, the flow restriction restricting gases flow through the chamber which can be detected by the pressure/flow sensor.

Preferably, the apparatus comprises a patient interface sensor operative to generate a signal indicative of whether a patient interface is connected to the apparatus, and to activate the disinfection mode only when the signal indicates that a patient interface is not connected to the apparatus. The patient interface sensor may be operative to detect the presence of a cap or other attachment used in disinfection on one end of the intermediate passageway, and to generate the signal indicative that a patient interface is connected to the apparatus, when no cap or other disinfection mode attachment is detected.

Preferably, the apparatus comprises a disinfection mode sensor operative to generate a disinfection mode activation signal. The disinfection mode sensor may be operative to generate the disinfection mode activation signal by detecting at least one of: a cap or other disinfection mode attachment being mounted on one end of the intermediate passageway; the chamber being mounted on the housing; and/or a clinician or user input.

The apparatus may comprise a chamber liquid level detector operative to generate a signal indicative of the liquid level in the chamber. The apparatus may be operative, in dependence upon the liquid level signal detected, to vary at least one of: the flow rate of the gases flow exiting the chamber; the target dewpoint temperature of the vapour; and/or the duration of the disinfection mode.

A liquid level detector may additionally or alternatively be used to detect whether the chamber includes a sufficient level of liquid to complete a disinfection process. This may be a predetermined, fixed level or an adaptable level based on the parameters of the process being used. An alarm or indicator light or display may alert a user to an insufficient level of liquid. Disinfection mode may be inhibited until sufficient liquid is present in the chamber, or a notification may be generated indicating that disinfection has not completed.

Preferably, the required level of liquid is determined prior to initiation of disinfection to optimize the disinfection mode. Note, however, that rather than having to repeat disinfection in the event of a shortage of liquid, the target dewpoint temperature and/or the duration of the disinfection process may simply be increased, with these being closer to parameters used in prior art arrangements that do not include the use of moist heat.

Additionally or alternatively, the chamber may be provided with a visible mark whereby a user fills the chamber to or above that mark prior to disinfection.

The apparatus includes a drying mode that is initiated subsequent to the disinfection mode, wherein the intermediate passageway and optionally other components are dried. This may be achieved using heat generated by the heater when all of the liquid has been completely used, or via a separate heater element, or by increasing the gases flow rate through the intermediate passageway, for example. The duration of the drying mode may be predetermined, clinician or user controlled, or controlled in dependence on moisture levels detected in the intermediate passageway.

According to a second aspect, there is described a cap for use with a respiratory assistance apparatus according to the first aspect, the cap comprising an engaging formation arranged to engage with one end of the intermediate passageway of the respiratory assistance apparatus to mount the cap on said end, the cap comprising a flow restrictor arranged to restrict flow through the intermediate passageway when the cap is so mounted to provide back pressure in the intermediate passageway during the disinfection mode.

The flow restrictor may comprise a filter. The filter may be an antibacterial filter. The filter may be arranged to prevent leakage of liquid through or around the filter. The geometry of the cap may be arranged to prevent liquid contacting the filter.

The flow restrictor may comprise an orifice.

The cap may comprise a temperature sensor operative to generate a signal indicative of the temperature of the gases flow at or proximate to the cap.

The cap may comprise an identifier. Non-limiting examples of a suitable identifier include a magnet, an RFID tag, or a source of electrical resistance such as a resistor. The identifier may simply identify the type of device (i.e., the cap as opposed to other items that may be connected thereto). This may be used by the apparatus to switch to a disinfection mode on detection of the cap and/or to generate an error message to a user that the apparatus is not correctly configured if a disinfection mode is otherwise selected and the cap is not detected.

The cap may comprise an open-ended cavity which defines a volume suitable for measuring an amount of a liquid for use in the apparatus.

According to a third aspect, there is described a method of disinfecting a respiratory assistance apparatus adapted to deliver a gases flow to a user or patient, according to a disinfecting mode, the apparatus comprising a chamber provided with a port in fluid communication with an intermediate passageway, the method comprising the steps of: heating a liquid in the chamber to produce vapour at or above a target dewpoint temperature; delivering the vapour through the port to the intermediate passageway; and continuing to deliver vapour at or above the target dewpoint temperature through the port to the intermediate passageway throughout a predetermined duration of the disinfection mode.

The target dewpoint temperature may be predetermined, that is, fixed prior to initiation of the disinfection mode.

The method may include a step, prior to the heating step, of setting or selecting the target dewpoint temperature before or after initiation of the disinfection mode.

The target dewpoint temperature may be greater than <NUM>, is preferably greater than <NUM>, and is most preferably greater than <NUM>.

The method may include an additional step of controlling the duration of the disinfection mode in dependence upon the target and/or a measured dewpoint temperature. The method may include an additional step of referencing a lookup table using an algorithm or a formula relating the duration of the disinfection mode to a range of target and/or measured dewpoint temperatures.

The method includes an additional step of drying the intermediate passageway, after delivering the vapour for the predetermined duration.

As with previous and further aspects, the liquid is water.

According to a fourth aspect, there is described in a respiratory assistance apparatus adapted to deliver a gases flow to a user or patient, comprising a housing provided with a chamber and a heater, the chamber comprising at least one port connected to, or arranged to be connected to, at least one intermediate passageway, the apparatus being operative according to a disinfection mode of predetermined profile in which the heater heats liquid in the chamber to produce vapour at or above a target dewpoint temperature, the apparatus being arranged such that the vapour is delivered to the intermediate passageway to disinfect the intermediate passageway with moist heat, the apparatus further comprising a cap arranged to be mounted at one end of the intermediate passageway, the cap being provided with a flow restriction arranged to provide a back pressure in the intermediate passageway during the disinfection mode.

The heater may subsequently be used, once all liquid in the chamber has been completely used, to heat the gases flow within the apparatus to dry the intermediate passageway.

According to a fifth aspect, there is described a respiratory assistance apparatus adapted to deliver a gases flow to a user or patient, comprising a housing having a patient outlet, a chamber, and an intermediate gases flow path between the patient outlet and the chamber, the apparatus being operative during a disinfection mode of predetermined profile, to generate and deliver vapour at or above a target dewpoint temperature from the chamber to the intermediate gases flow path to disinfect the intermediate gases flow path with moist heat throughout the predetermined duration of the disinfection mode.

According to a sixth aspect, there is described a method of disinfecting a respiratory assistance apparatus adapted to deliver a gases flow to a user or patient according to a disinfecting mode comprising the steps of: connecting a chamber to the apparatus; heating liquid in the chamber to produce vapour at or above a target dewpoint temperature; and delivering the vapour to a component of the apparatus to disinfect that component with moist heat.

According to a seventh aspect, there is described a respiratory assistance apparatus adapted to deliver a gases flow to a patient, comprising a housing having a gases inlet and a patient outlet, the gases inlet being in communication with the patient outlet via an intermediate passageway, the apparatus further comprising a humidifier arranged between the gases inlet and the patient outlet and comprising a chamber and heater arranged, in a respiratory assistance mode, to humidify the gases flow prior to delivery of the gases flow to the patient outlet, the apparatus also being arranged, according to a disinfection mode of predetermined profile, to control the heater to heat the liquid in the chamber to produce vapour at or above a target dewpoint temperature, and to deliver the vapour to the intermediate passageway to disinfect the intermediate passageway with moist heat throughout the predetermined duration of the disinfection mode.

According to an eighth aspect, there is described a respiratory assistance apparatus adapted to deliver a gases flow to a user or patient, comprising a housing provided with a gases inlet, the gases inlet being in fluid communication with a patient outlet to deliver a gases flow to the patient via an intermediate passageway, and a chamber and a heater, a controller being provided operative to control the apparatus according to a disinfection mode in which the heater heats liquid to produce vapour at or above a target dewpoint temperature, the apparatus being arranged such that the vapour is delivered to the intermediate passageway to disinfect the intermediate passageway with moist heat, the disinfection mode having a predetermined duration, the controller being operative to subsequently control the apparatus such that the vapour at or above the target dewpoint temperature continues to be delivered to the intermediate passageway throughout the predetermined duration of the disinfection mode.

The apparatus may comprise a safety cap provided with a connector arranged to fluidly couple the safety cap to a downstream end of the intermediate passageway, and a duct forming a vapour flow path into the safety cap, the safety cap being adapted to disperse and/or condense vapour received thereby. The safety cap may comprise a condensing surface onto which vapour from the duct condenses and/or a condensate reservoir adapted to receive condensate generated by the safety cap.

According to another aspect, there is provided a respiratory assistance apparatus adapted to deliver a gases flow to a user or patient, the apparatus comprising a housing provided with or configured to receive a chamber and a heater, the chamber comprising at least one port connected to, or arranged to be connected to, at least one intermediate passageway, the apparatus being operative according to a disinfection mode to heat liquid in the chamber to generate vapour at or above a target dewpoint temperature and deliver the vapour from the chamber to the intermediate passageway to disinfect the intermediate passageway with moist heat, the apparatus further comprising a safety cap provided with a connector arranged to connect and/or fluidly couple the safety cap to a downstream end of the intermediate passageway, thereby defining a gases pathway from the chamber to the safety cap, the safety cap being adapted to, in use in the disinfection mode, disperse and/or condense at least a portion of vapour received thereby.

The may comprise a duct defining the gases pathway into the safety cap, the safety cap further comprising a condensing surface onto which vapour from the duct condenses. Additionally or alternatively, the apparatus may comprise a condensate collector adapted to collect at least a portion of the condensate generated by the safety cap.

According to another aspect, there is provided a safety cap for use with the respiratory apparatus of any one of the previous aspects, the safety cap comprising a connector arranged to fluidly couple the safety cap to a downstream end of the intermediate passageway, and a duct forming a vapour flow path into the safety cap, the safety cap being adapted to, in use in a disinfecting mode, disperse and/or condense vapour received thereby.

Preferably, the safety cap comprises a condensing surface onto which vapour from the duct condenses. The condensing surface may have a surface area greater than the cross sectional area of the duct and/or a domed ceiling into which the duct directs the vapour flow path. A skirt may extend generally downwards from a peripheral edge of the ceiling to define an area for holding vapour and/or directing flow of condensate.

The safety cap may be adapted to direct vapour radially outwardly of the connector prior to the vapour impacting on the condensing surface, aiding in dispersion of the vapour and reducing the likelihood of localized hot spots. The duct may be defined by a wall having at least one vapour outlet through which vapour can flow away from a longitudinal axis of the duct. The or each vapour outlet comprises a slit formed in the wall defining the duct. The condensing surface may be connected to the duct via at least one spoke extending between the condensing surface and the duct. A vapour outlet may be provided in the wall of the duct between one or more adjacent pairs of said spokes. The duct may be terminated at an end distal from the intermediate passageway by an end wall.

The safety cap may comprise an identifier. The identifier may comprise a resistor, the resistance of which is detected by the apparatus when the safety cap is mounted on the apparatus.

The safety cap may comprise one or more surfaces having a hydroscopic structure arranged to promote the formation of condensate. Additionally or alternatively, microstructures may be arranged to channel flow of condensate. The safety cap may comprise a condensate collector that defines a reservoir into which condensed vapour is collected. The condensate collector may comprise a substantially annular catch tray extending around the periphery of the connector. The condensate collector may comprise a spout to facilitate pouring of liquid from the condensate reservoir. Further, the condensate reservoir may be arranged to measure a pre-determined volume of liquid for use during the disinfecting mode of the respiratory apparatus.

According to another aspect, there is provided a respiratory assistance apparatus adapted to deliver gas to a user or patient, the apparatus comprising a housing provided with or configured to receive a chamber and a heater, the chamber comprising at least one gas port connected to, or arranged to be connected to, at least one intermediate passageway, the apparatus being operative according to a vapour disinfection mode to disinfect the at least one intermediate passageway with moist heat, the apparatus comprising a controller for controlling operation of the apparatus in the disinfection mode, to activate the heater to heat liquid in the chamber to generate vapour at or above a target dewpoint temperature for at least a portion of the duration of the disinfection mode.

In an initialization phase, the controller may be arranged to detect the presence or absence of any one or more of the chamber, an attachment for use with the apparatus in the disinfection mode, and liquid in the chamber, and/or a level of liquid in the chamber.

The apparatus may comprise a compressor in fluid communication with the chamber for urging gases through the chamber to the at least one intermediate passageway, wherein during a warm up phase and/or a main disinfecting phase, the controller is adapted to control the heater to generate vapour and to control the compressor to provide no or only a low level of increased flow.

Prior to termination of the disinfection mode, the controller may be configured to control the compressor to provide a ramped increase in flow so as to dry and/or cool down the at least one intermediate passageway. The controller may be configured to switch off the heater and/or the compressor upon detection of any one or more of an absence of liquid in the chamber, a temperature of a portion of the apparatus falling below a predetermined threshold, a temperature detected inside the apparatus falling below a predetermined threshold and elapse of a predetermined time period.

Preferably, the compressor is controlled to slowly discharge any remaining vapour or steam from the chamber near the end of the disinfection mode and then to provide a higher flow rate subsequent thereto so as to provide for accelerated drying and/or cooling. The initial low flow helps to prevent injury since relatively high energy steam or vapour is ejected relatively slowly before the lower energy air stream is forced from the chamber at a higher flow.

The controller may be arranged to generate a signal indicative of whether the disinfection mode was completed successfully and/or log one or more parameters relating to the disinfection mode.

Further aspects of the disclosure, which should be considered in all its novel aspects, will become apparent from the following description.

A number of embodiments of the disclosure will now be described by way of example with reference to the drawings.

Throughout the description like reference numerals will be used to refer to like features in different embodiments.

The present disclosure provides a respiratory assistance apparatus that provides a convenient, effective and reliable method of disinfecting at least a portion of the apparatus with moist heat during a disinfection mode, which portion defines, at least in part, a transport path for a humidified gases flow generated by the apparatus. According to some embodiments, the at least a portion of the apparatus comprises an internal passageway provided at least partially inside the apparatus. The present disclosure also provides a method of disinfecting a respiratory assistance apparatus and attachments for use with such method of disinfecting the respiratory assistance apparatus.

A chamber is provided on or at the apparatus in which liquid can be heated to produce vapour or steam, the vapour being delivered to the at least a portion of the apparatus (such as the internal passageway) to disinfect that portion with moist heat. According to the invention, the chamber is the same humidification chamber used to humidify the gases flow prior to delivery to the patient during normal use of the apparatus to provide respiratory assistance.

According to the invention, water and therefore vapour are used to disinfect said at least a portion of the apparatus with moist heat.

The source of liquid that is used for disinfection may be a self contained part of the apparatus, namely located on or at the apparatus in use of the disinfection mode.

Referring to the Figures, a respiratory assistance apparatus <NUM> comprises a housing <NUM> which may be generally cuboidal and may be arranged to be placed on a table or tray, or mounted on a wall or some other support, as required or preferred.

A supply gases inlet <NUM> is provided, for example on the rear of the housing, and is in fluid communication with a gases source such as a blower, fan or compressor (not shown), preferably mounted in the housing <NUM> for delivering a gases flow. There may be ductwork within the housing which connects the gases source with the supply gases inlet <NUM>, and that ductwork may be of a length and path direction selected as required.

The housing <NUM> is further provided with a supply gases outlet <NUM>, which may project from the front of the housing <NUM>, from which the gases flow exits.

Adjacent the supply gases outlet <NUM> is a patient inlet <NUM> which may also project from the front of the housing <NUM>, which leads to a patient outlet <NUM> which may project from the top of the housing <NUM>. The patient inlet <NUM> and the patient outlet <NUM> are connected by an intermediate passageway, which in this example comprises an elbow <NUM> that is bent along its length through <NUM>°. The patient inlet <NUM> and patient outlet <NUM> may be otherwise positioned depending on the apparatus configuration, with the elbow <NUM> configured to provide fluid communication between the patient inlet <NUM> and the patient outlet <NUM>. Thus, the elbow <NUM> may be of some alternative configuration, including but not limited to straight, curved, or bent in more than one location.

A humidifier is provided having a chamber <NUM> comprising a chamber inlet port <NUM> and a chamber outlet port <NUM>. The ports <NUM>, <NUM> are provided on the rear of the chamber <NUM>, and sealingly engage with the supply gases outlet <NUM> and the patient inlet <NUM>, respectively, such that in use the gases flow enters the chamber <NUM> from the supply gases outlet <NUM> through the chamber inlet port <NUM> and exits the chamber <NUM> to the patient inlet <NUM> through the chamber outlet port <NUM>.

The chamber <NUM> may be removably mounted on the housing <NUM>, and in one example, may be slidably mounted on the front of the housing <NUM> by sliding the chamber <NUM> towards the rear of the housing <NUM> until the ports <NUM>, <NUM> and the ports <NUM>, <NUM> engage. In another example, the chamber <NUM> may be permanently mounted on the housing <NUM>.

A heater <NUM> is provided which in this example comprises a heater plate <NUM> on the housing <NUM>, below the chamber <NUM>. Other forms of heater are envisaged and these may include a heater element built into the chamber <NUM> itself or a non-contact heater such as an induction heater for example.

A controller is provided in the housing <NUM> which is arranged to control the gases source and the heater. It will be appreciated that by providing appropriate communication means, control may be effected, at least in part, remote from the apparatus.

The apparatus <NUM> is operative according to at least two modes: a respiratory mode and a disinfection mode.

In the respiratory mode, the gases source is controlled to provide a gases flow to the chamber <NUM>. The gases flow passes into the chamber inlet port <NUM>, across the chamber <NUM>, and out of the chamber outlet port <NUM>. The heater <NUM> is controlled to heat liquid in the chamber <NUM> such that the incoming gases flow passes over the liquid and is humidified by vapour generated from the heated liquid. This heated and humidified gases flow exits the chamber <NUM> via the chamber outlet port <NUM> and is delivered to a patient <NUM> via the elbow <NUM> and the patient outlet <NUM>. While various interfaces are known and may be selected based on operational parameters and user preferences, <FIG> shows a particular inspiratory tube <NUM> having a heating element <NUM> running therethrough, and coupled at one end to the patient outlet <NUM> and at the other to a patient interface <NUM> (shown as a nasal cannula).

In the disinfection mode, the gases source may be switched off, or may be controlled to continue delivering a gases flow into the chamber <NUM> at the same or a different flow rate. The heater is controlled to heat liquid in the chamber <NUM> to produce vapour at or above a target dewpoint temperature. The vapour fills the chamber <NUM> and is delivered into the elbow <NUM> and through the patient outlet <NUM>. The vapour in the elbow <NUM> provides the moist heat that serves to disinfect the elbow <NUM> and the patient outlet <NUM>. The disinfection mode is operative for a predetermined duration in which the heater <NUM> is controlled such that vapour continues to be generated and supplied to the elbow <NUM> throughout the duration of the disinfection mode.

The target dewpoint temperature is set sufficiently high that the vapour provides the moist heat necessary to disinfect the elbow <NUM>, at least over the duration of the disinfection mode. The target dewpoint temperature is inversely proportional to the duration of the disinfection mode, at least within a preferred temperature range of <NUM> to <NUM>. Thus, a fixed target dewpoint temperature and disinfection mode duration may be predetermined, or may be variable according to a user selection of one of the target dewpoint temperature or the disinfection mode duration. A lookup table may be provided which relates the duration required for a range of target dewpoint temperatures. As an example only, a range of dewpoint temperatures between <NUM> and <NUM> may achieve sufficient disinfection efficacy over a disinfection mode duration of between <NUM> and <NUM> minutes, preferably around <NUM> minutes. As will be appreciated, to ensure sufficient disinfection efficacy, a safety margin may be applied to the dewpoint temperature and/or duration.

In this example, the disinfection mode therefore requires no external components, or modifications to the apparatus <NUM>, instead using the components of the humidifier in a different manner to achieve disinfection. No external disinfection hoses or the like are required, and it is not required to remove the chamber <NUM> from the housing <NUM>.

Optionally, an end cap <NUM> is provided which is arranged to be mounted on the end of the elbow <NUM> at the patient outlet <NUM>.

The cap <NUM> comprises an engaging formation <NUM> arranged to engage with the end of the elbow <NUM> at the patient outlet <NUM> to mount the cap <NUM>. The cap <NUM> may further comprise a flow restrictor <NUM> arranged to restrict flow through the elbow <NUM> when the cap <NUM> is so mounted, to provide back pressure in the elbow <NUM> during the disinfection mode. The cap <NUM> may further comprise an antibacterial filter. The cap <NUM> may also comprise an identifier such as a RFID tag, or a resistor which is used by the apparatus <NUM> to determine if the cap <NUM> is mounted on the elbow <NUM>.

The apparatus <NUM> may comprise a chamber sensor operative to generate a signal indicative of whether the chamber <NUM> is mounted on the apparatus <NUM>. The chamber sensor may be operative to generate a signal indicative of whether a specific chamber or type of chamber is mounted on the apparatus <NUM>. The chamber sensor may comprise the combination of a pressure/flow sensor and a flow restriction on the specific chamber, the flow restriction restricting gases flow through the chamber which can be detected by the pressure/flow sensor.

The apparatus <NUM> may comprise a patient interface sensor operative to generate a signal indicative of whether a patient interface is connected to the apparatus <NUM>, and to activate the disinfection mode only when the signal is indicative that a patient interface is not connected to the apparatus <NUM>. The patient interface sensor may be operative to detect the presence of the cap <NUM> on the end of the elbow <NUM> at the patient outlet <NUM>, and to generate the signal indicative that a patient interface is connected to the apparatus <NUM>, when no cap <NUM> is detected.

The apparatus <NUM> may comprise a disinfection mode sensor operative to generate a signal indicative that the apparatus <NUM> is to operate according to the disinfection mode. The disinfection mode sensor may be operative to generate the signal by detecting at least one of: the cap <NUM> being mounted on the end of the elbow <NUM> at the patient outlet <NUM>; the chamber <NUM> being mounted on the housing <NUM>; and/or a user input.

The apparatus <NUM> may comprise a chamber liquid level detector operative to generate a signal indicative of a liquid level in the chamber <NUM>. The apparatus <NUM> may be operative, in dependence upon the liquid level signal detected, to vary at least one of: the flow rate of the gases flow; the target dewpoint temperature of the vapour; and/or the duration of the disinfection mode.

The liquid level detector may indicate when the disinfection liquid has been entirely used, so as to determine whether a sufficient duration and dewpoint temperature combination has been achieved to provide the desired disinfection efficacy.

The apparatus <NUM> provides a drying mode, initiated subsequent to the disinfection mode, wherein the elbow <NUM> and optionally other components of the gases flow path are dried. This may be achieved using heat generated by the heater when all of the liquid in the chamber <NUM> has been entirely used, or via a separate heater element, or via increasing the gases flow rate through the elbow <NUM>, for example. The duration of the drying mode may be predetermined, user controlled, or controlled in dependence on moisture levels detected in the elbow <NUM>.

A drying mode may also be provided to dry the moisture from components of the gases flow path, such as by operating the blower for a sufficient period after the liquid has been completely used, or after the heater plate has been switched off and the remaining liquid cools and its evaporation approaches an equilibrium state.

In another example, not according to the invention as claimed, another method of disinfecting the elbow <NUM> is provided. This example uses a separate disinfection chamber <NUM> which is mounted on the housing <NUM> for the duration of the disinfection mode. This method can therefore be used on an apparatus not provided with a humidification chamber <NUM>, or otherwise requires removal of the humidification chamber <NUM> when provided.

In this example, the disinfection chamber <NUM> is mounted on the housing <NUM> with the chamber inlet port <NUM> sealingly connected to the supply gases outlet <NUM> on the housing <NUM>. A disinfection hose <NUM> is connected between the chamber outlet port <NUM> and the end of the elbow <NUM> at the patient outlet <NUM>. End cap <NUM> is mounted on the end of the elbow <NUM> at the patient inlet <NUM>.

During the disinfection mode, the heater heats liquid in the disinfection chamber <NUM> to produce vapour at or above a target dewpoint temperature. The vapour flows from the disinfection chamber <NUM>, along the disinfection hose <NUM> and into the end of the elbow <NUM> at the patient outlet <NUM>. The vapour flows along the elbow <NUM>, disinfecting the elbow <NUM>, and exits via the end cap <NUM> on the end of the elbow <NUM> at the patient inlet <NUM>.

The disinfection chamber <NUM> may be supplied pre-charged with a suitable volume of disinfecting liquid, or may be provided with an injector inlet or the like through which a suitable volume of disinfecting liquid may be introduced into the chamber <NUM>.

Referring additionally to <FIG>, a safety cap <NUM> is provided for mounting on the end of the elbow <NUM> at the patient outlet <NUM> of the apparatus <NUM> during a disinfection mode. The safety cap <NUM> is used during a disinfection mode in which the humidifier chamber <NUM>, or the disinfection chamber <NUM> in embodiments not according to the invention as claimed, is mounted on the apparatus <NUM> to generate vapour that passes through the apparatus <NUM>, through the elbow <NUM>, and exits the apparatus <NUM> via the patient outlet <NUM>. It will be appreciated that without safety measures, vapour exiting the patient outlet <NUM> could scald a user or other person near the apparatus <NUM>. Similarly, portions of the apparatus <NUM> impinged by the vapour could become dangerously warm. Broadly speaking, the safety cap <NUM> provides a means of mitigating these risks by dispersing the vapour, so that it is not concentrated in a small area, and by condensing the vapour.

The safety cap <NUM> comprises a connector <NUM> arranged to connect the safety cap <NUM> with the patient outlet <NUM> at one end of the elbow <NUM> and a duct <NUM> extending through the connector <NUM> to form a gases flow path with the patient outlet <NUM>. The vapour duct <NUM> is provided, at a position distal from the connector <NUM>, with at least one vapour outlet <NUM> through which vapour exits the duct <NUM> in a generally radially outward direction but is retained within the safety cap <NUM>. A concave inner roof <NUM> provides a condensing surface positioned above the end of the duct <NUM> and above the vapour outlet <NUM> such that vapour from the vapour outlet <NUM> rises and contacts the roof <NUM>. The vapour condenses on the roof <NUM>, and the condensate drops from the roof <NUM> and is collected in a condensate reservoir <NUM> below.

The risk of vapour directly contacting a user adjacent the apparatus <NUM> is therefore reduced by virtue of the tortuous path defined by the safety cap <NUM>, and at least a portion of the vapour is safely condensed and collected within condensate reservoir <NUM> for later disposal.

The safety cap <NUM> is arranged to provide a vapour flow path that dissipates the heat from the vapour and/or prevents emission of a hazardous stream of vapour, at least during normal operating conditions. In particular, the vapour duct <NUM> initially directs the vapour upwardly away from the patient outlet <NUM>, along a central axis of the safety cap <NUM>. The end of the duct <NUM> is closed by domed end wall <NUM> (as described further below) such that vapour then flows generally radially outwardly through vapour outlet(s) <NUM>, and subsequently upwardly into contact with roof <NUM>.

The vapour duct <NUM> and vapour outlet <NUM> prevent vapour from flowing up the duct <NUM> directly into contact with the roof <NUM> and creating a hot spot on the roof <NUM>. Directing the vapour radially away from the vapour duct <NUM> also prevents any condensate from undesirably flowing back down the duct <NUM> and into the patient outlet <NUM>.

The roof <NUM> forms a condensing surface which is impacted by the vapour and which has a surface area that is considerably greater than the cross-sectional area of the duct <NUM>, so that heat energy of the vapour is not concentrated on a particular area of the roof <NUM>. The roof <NUM>, together with other components forming the safety cap <NUM>, serves to dissipate heat from the condensing vapour.

In the illustrated example, the safety cap <NUM> is of multi-piece construction broadly comprising a base piece forming a lower part 44A of duct <NUM> and connector <NUM>, the condensate reservoir <NUM> mounted on the base piece around connector <NUM>, and a cap piece comprising an upper part 44B of duct <NUM> and roof <NUM>. These pieces may be arranged to be connected together in any suitable manner, including using push fit or snap fit type connections. One or more pieces may alternatively be constructed as a single component.

Connector <NUM> is a tubular connector comprising a duct connector <NUM> and an optional electrical connector <NUM>. Connector <NUM> may be of the same or similar structure to a gases tube connector of the type used to connect a gases tube to the apparatus <NUM> in normal use, i.e., between the apparatus <NUM> and a patient interface. When pushed onto the apparatus <NUM>, the duct connector <NUM> receives part of the patient outlet <NUM> of the apparatus <NUM> to form a vapour flow path, whilst the electrical connector <NUM>, when provided, forms an electrical connection with the apparatus <NUM>. Resilient clips <NUM> releasably engage with corresponding formations on the apparatus <NUM> to secure the connector <NUM> onto the apparatus <NUM>. Clips <NUM> can be pressed inwardly to release the connector <NUM> from the apparatus <NUM>.

The electrical connector <NUM> includes any power and/or sensor connections as are required between the safety cap <NUM> and the apparatus <NUM>. The electrical connector <NUM> may include an identifier to enable the apparatus <NUM> to recognize that the safety cap <NUM> is connected to the apparatus <NUM>. Once the safety cap <NUM> is recognized, the apparatus <NUM> may automatically begin a disinfection mode for example. The apparatus <NUM> may be arranged to prevent activation of a disinfection mode until the safety cap <NUM> has been connected and recognized by the apparatus <NUM>. In one example, the electrical connector <NUM> may include an identification resistor which is used to detect the presence of the safety cap <NUM> on the apparatus <NUM>.

Condensate reservoir <NUM> comprises a substantially annular catch tray extending around connector <NUM>. The catch tray <NUM> is generally circular or elliptical when viewed from above, and is of larger diameter than roof <NUM> to minimize spillage of condensate dropping from the roof <NUM>. The catch tray <NUM> further preferably comprises a spout <NUM> from which condensate can be poured to empty the tray <NUM> after vapour disinfection. The catch tray <NUM> may also be used to measure a predetermined volume of fluid prior to commencement of a disinfection mode. The catch tray <NUM> may comprise measuring indicia for this purpose, and/or the volume of the catch tray <NUM> may correspond to the volume of fluid required. Thus the fluid may be measured in the catch tray <NUM> and then poured into the humidifier chamber <NUM>, or the disinfection chamber <NUM>, using the spout <NUM>. The periphery of the catch tray <NUM> may comprise one or more tabs or other gripping formations <NUM> to facilitate gripping of the tray <NUM> by a user.

The upper cap piece comprises upper duct part 44B which is mounted on, and fluidly connected to, lower duct part 44A. Upper duct part 44B is closed off by domed end wall <NUM>. Below the domed end wall <NUM> are a plurality of vapour outlets <NUM> which in this example comprise equi-spaced slits formed in the duct wall. Any number and/or size and/or shape of vapour outlets <NUM> can be provided as required. The roof <NUM> is joined to the upper duct part 44B by a plurality of radially outwardly extending spokes <NUM>, a vapour outlet <NUM> being provided between each pair of spokes <NUM>. Spokes <NUM> add thermal mass and heat transfer conduits to the safety cap <NUM> to assist in cooling the vapour by absorbing heat therefrom. The size and/or number of the spokes <NUM> may be selected accordingly. The periphery of the concave roof <NUM> leads to a downwardly directed skirt <NUM> which assists in directing condensate down into the catch tray <NUM>, minimizing spillage. Skirt <NUM> also prevents or reduces the amount of vapour ejected via the vapour outlets <NUM> that escapes the cap <NUM> and is able to contact a user, maintaining safe operation, at least during normal operating conditions.

With reference to <FIG> and <FIG> in particular, roof <NUM> may be transparent or opaque.

Safety cap <NUM> may optionally further comprise one or more fins or other formations on the exterior of at least part of the cap <NUM>, to prevent a user directly contacting the cap surface and/or to increase heat dissipation from the cap surface, for example roof <NUM>. The inside of the roof <NUM> may comprise a hydroscopic structure to promote formation of condensation. The roof <NUM> and/or skirt <NUM> could comprise microstructures to channel condensate droplet movement down to catch tray <NUM> as quickly and/or directly as possible.

While the Figures show a particular embodiment of a safety cap according to the disclosure, various modifications or alternatives are included within the scope of the disclosure. For example, other structures that serve to disperse the vapour to prevent localized hot spots are also included within the scope of the disclosure, as are other structures that promote condensation.

With reference to <FIG>, apparatus <NUM> is arranged to operate according to a disinfection mode. This mode may be activated automatically, for example, when safety cap <NUM> is mounted on the apparatus <NUM>, or activated when selected by a user. The disinfection mode may be prevented from activating until the apparatus <NUM> detects the safety cap <NUM>, the cap <NUM>, or some other attachment used in the disinfection mode.

Referring to <FIG>, the disinfection mode is controlled via a disinfection controller <NUM> which receives information from sensors and interacts with a gas flow control system <NUM> and a gas temperature control system <NUM>. More particularly, flow control system <NUM> may be operable to control a pressure and/or flow of gas along a gas flow path through the apparatus, at least when in the disinfection mode. It will be appreciated that the same circuitry is used to control flow when in a respiratory mode. Conversely, the temperature control system <NUM> may control heating of liquid used in disinfection mode, such as via a heater plate provided in thermal communication with a chamber holding said liquid. According to some embodiments, heating may be provided along the gas flow path to maintain a desired dewpoint temperature and prevent condensation forming. Such heating may comprise a resistance wire heating element provided in a wall defining the gas flow path. Again the same or different circuitry may be employed to similar effect when in a respiratory mode.

With particular reference to <FIG> and <FIG>, the disinfection controller <NUM> may be initiated by detecting when the safety cap <NUM> is connected to the apparatus <NUM> using an identifier on the safety cap <NUM>. In one example, this detection may be via a measurement of the electrical resistance of a resistor in the electrical connector <NUM> of cap <NUM>. The detected resistance of the resistor is compared by the disinfection controller <NUM> to a predetermined resistance value associated with the safety cap <NUM>. For example if the detected resistance exceeds the predetermined resistance value, this signals to the disinfection controller <NUM> that the safety cap <NUM> is connected to the apparatus <NUM>. The disinfection controller <NUM> may then automatically initiate a disinfection mode. The disinfection controller <NUM> may alternatively use the resistance comparison to allow or prevent an operator from initiating a disinfection mode. As will be appreciated, other forms of detection may be used. For example, apparatus <NUM> may be operable to detect the presence of an RFID tag form part of the safety cap <NUM>. Optical identification means may alternatively be provided. Alternatively, the detection may be omitted with the disinfection mode being initiated by user input. Such control may additionally or alternatively be used for other embodiments of the invention that do not include the safety cap <NUM>. For example, it may be used to detect the presence of cap <NUM> or some other attachment used in the disinfection mode.

Flow control system <NUM> controls the motor speed of the blower, fan or compressor of apparatus <NUM>, at least when in a disinfection mode. The flow control system <NUM> processes gas flow signals from flow sensors which may be positioned at one or more points along the gas flow path. Additionally or alternatively, flow may be determined based on a signal from a blower motor speed sensor. The apparatus <NUM> may comprise lookup tables that translate a given motor speed into a flow for determined apparatus configurations (e.g. whether cap <NUM> or safety cap <NUM> is connected).

Chamber detection system <NUM> may be configured to process the outputs from the gas flow sensor and the blower motor speed sensor to determine whether or not the humidifier chamber <NUM>, or the disinfection chamber <NUM>, or safety cap <NUM>, or cap <NUM>, or some other attachment is connected to the apparatus, and whether to initiate the disinfection mode accordingly. Known flow profiles of components may be stored in a memory of the apparatus <NUM> and used to determine which components are connected based on a comparison with detected flow.

Gas temperature control system <NUM> controls the heat produced by the heater plate of the humidifier of apparatus <NUM> using a signal from a gas temperature sensor at or near the patient outlet <NUM>, and/or a signal from a heater temperature sensor at or near the chamber. The gas temperature sensor may be provided in or at the elbow <NUM>, or elsewhere disinfection is required.

Liquid out detection system <NUM> may be configured to detect when there is no more liquid in humidifier chamber <NUM> using signals from the ambient temperature sensor and the heater plate temperature sensor.

With reference to <FIG>, a preferred embodiment of an algorithm <NUM> used by the controller <NUM> is described that uses the systems <NUM>, <NUM>, <NUM> and <NUM>, and sensors described above.

The algorithm <NUM> may begin at step <NUM> with checks that the apparatus is properly configured for performing the disinfection cycle. For example, controller <NUM> may detect whether safety cap <NUM> (or other disinfection mode equipment) and chamber <NUM> are fitted to apparatus <NUM>. There may also be a check that there is liquid in the chamber <NUM>. The latter may comprise not just detecting a presence or absence of a liquid but a level thereof. While any form of liquid level detector may be used, liquid level may be determined based on the amount of energy used to generate a given change in temperature. For example, current or power supplied to the heater plate may be monitored and a water level inferred based on whether a particular temperature increase is achieved within a predetermined time range. Too rapid a rise in temperature may indicate too little liquid in the chamber. Conversely, a less than expected rise in temperature within a given time period may indicate that too much liquid has been provided. As discussed elsewhere, the disinfection cycle terminates with a drying cycle and too much liquid may prevent this or undesirably lengthen the cycle.

At step <NUM>, the heater plate is controlled to heat the liquid and generate vapour which flows from the chamber, through the elbow <NUM> and into duct <NUM> of safety cap <NUM>, via patient outlet <NUM>. Steps <NUM> and <NUM> may be combined to some extent where liquid level is determined based on the heater plate duty cycle. Vapour is maintained in the elbow <NUM> at a temperature above a minimum threshold, such as <NUM> for example, for a time period necessary for a sufficient level of disinfection. During warm up of the apparatus <NUM> and the disinfection part <NUM> of the cycle, preferably, flow controller <NUM> may deactivate the compressor used to enhance flow of gas through the apparatus, with flow being generated due to expansion resulting from vaporization. Alternatively, the flow controller <NUM> may control the compressor to only generate a relatively small increase in flow. Equipment used for respiratory assistance is configured to generate relatively low temperature humidified gases flows that are suitable for receiving in a patient airway. Higher temperatures are required for disinfection. Reducing or inhibiting flow enhancement provided by the compressor can enable vapour to be generated with the required dewpoint temperature using substantially the same apparatus as that used for providing respiratory assistance and without requiring additional heating. For some compressors used for providing respiratory assistance, low levels of flow may be generated by applying power to a motor of the compressor in pulses, with "ON" pulses in which power is supplied thereto being interspersed by "OFF" cycles when no power is supplied to the motor. Braking may additionally or alternatively be provided.

Completion of the disinfection part <NUM> of the cycle may be determined based on stored cycle times for a given apparatus configuration and a predetermined or detected level of liquid present in the chamber <NUM> at the start of the process. Once detected, a cool down and drying phase <NUM> is initiated that ensures that the walls defining the gas pathway are dry and that they are cooled to a sufficient degree to be comfortably handled by a user and/or used to provide respiratory assistance. This phase <NUM> preferably comprises increasing the flow enhancement provided by the compressor to dry moisture from the apparatus and then to draw relatively cooler air through the apparatus to cool it. However, rapidly increasing the flow may generate a strong jet of heated humidified gas which may be hazardous. For example, even where safety cap <NUM> is used, a rapid increase in flow rate may result in a heated vapour stream or cloud forming about the safety cap <NUM> unless the safety cap <NUM> is designed to cope with such high flow rates. Thus, according to preferred embodiments, the flow controller <NUM> gradually ramps up or increases flow to gradually clear the apparatus <NUM> of high energy vapour.

At step <NUM>, an absence of liquid in chamber <NUM> is detected and the disinfection mode is terminated provided that the temperature of walls forming the gas pathway have been sufficiently cooled. For example, a temperature at the elbow <NUM> may be required to have fallen below a predetermined threshold. The heater plate and the compressor are turned off. A signal may be generated to indicate to the operator that the disinfection mode has finished.

The apparatus <NUM> may be arranged to log one or more parameters of the disinfection process, including but not limited to successful completion of a disinfection cycle, unsuccessful completion of a disinfection cycle, if unsuccessful the reason therefor, a length and/or temperature and/or temperature profile used in the cycle. Such data may be displayed on the apparatus <NUM> or communicated to remote processing equipment used to collate, analyze or present the data. Thus apparatus <NUM> may be adapted for wired and/or wireless communication of the data.

From the foregoing it will be seen that apparatus and methods are provided which allow reliable, effective disinfection of an intermediate passageway of a respiratory assistance apparatus, which do not require removal of the intermediate passageway, or any manual intervention or manual cleaning of the passageway. Additionally, apparatus and methods are provided in which disinfecting vapour is generated in situ on the apparatus. The components of the humidifier which are already present on the apparatus, are used in a disinfection mode.

Unless the context clearly requires otherwise, throughout the description, the words "comprise", "comprising", and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of "including, but not limited to".

Although this invention has been described by way of example and with reference to possible embodiments thereof, it is to be understood that modifications or improvements may be made thereto without departing from the scope of the invention as defined in the claims.

Claim 1:
A respiratory assistance apparatus adapted to deliver a gases flow to a user or patient, the apparatus comprising:
a housing (<NUM>) provided with a heater (<NUM>, <NUM>);
a chamber comprising at least one chamber port (<NUM>) configured to be connected to at least one intermediate passageway, the housing being configured to receive the chamber; and
a controller (<NUM>, <NUM>),
the controller (<NUM>, <NUM>) being operative to control the apparatus to operate according to a respiratory mode and a disinfection mode, and wherein the apparatus is arranged such that in the respiratory mode, a humidifier of the apparatus humidifies the gases flow prior to delivery of the gases flow to the user or patient, wherein the humidifier comprises the chamber, wherein the humidifying comprises the controller controlling the heater to heat water in the chamber such that the gases flow passes over the water and is humidified by vapour generated from the heated water;
wherein during a duration of the disinfection mode the controller is operative to control the heater (<NUM>, <NUM>) to heat water in the chamber (<NUM>) to produce vapour at or above a target dewpoint temperature;
wherein the apparatus is arranged such that, in use during the duration of the disinfection mode when the at least one intermediate passageway is connected to the chamber port: the vapour produced by heating the water in the chamber is delivered through the at least one chamber port (<NUM>) to the at least one intermediate passageway (<NUM>) connected to the chamber (<NUM>) by the chamber port (<NUM>), to disinfect the at least one intermediate passageway (<NUM>) with moist heat, wherein the vapour is at or above the target dewpoint temperature;
wherein the apparatus is configured by the controller subsequent to the disinfection mode to be operative in a drying mode, in which drying mode the at least one intermediate passageway (<NUM>) is dried.