Integration and mode switching for breathing apparatus

Abstract

The present disclosure relates to systems and apparatus that provide integration of different respiratory therapies into a single system or provide integrated switching between separate systems or apparatus that deliver different therapies, such as anesthesia and high-flow therapy. Aspects of the disclosure relate to various systems, devices, apparatus, switching mechanisms and multi-lumen assemblies that integrate the control of these therapies and provide flexibility in how and where a user controls switching between therapies.

Description

[Technical field]

[0001] The present disclosure relates to systems for delivering respiratory assistance to a patient, and to devices and systems that provide integration and switching of respiratory apparatus functions, particularly, but not exclusively, to integration and switching between anesthesia ventilation and high-flow modes of respiratory assistance. [Background technology]

[0002] Patients may lose respiratory function during anesthesia or sedation, or more generally during some medical procedures. Prior to a medical procedure, the patient may be pre-oxygenated by a medical professional to provide a reservoir of oxygen saturation, and this pre-oxygenation and CO2 flushing / washout may be performed in conjunction with high-flow respiratory support via a nasal cannula or other patient interface.

[0003] Once under general anesthesia, the patient must be intubated and ventilated. In some cases, intubation can be completed in 30-60 seconds, but in other cases, intubation can take significantly longer, especially if the patient's airway is difficult to cross (e.g., due to cancer, severe injury, obesity, or spasms in the neck muscles). Preoxygenation can mitigate the loss of oxygen saturation, but if the intubation procedure takes too long, the intubation process must be interrupted to allow the patient's oxygen saturation to increase to an adequate level. Interruptions to the intubation process can occur several times during a difficult intubation process, which is time-consuming and exposes the patient to significant health risks. After approximately three attempts, the medical procedure is abandoned.

[0004] In operating rooms, high-flow systems may be present for use during anesthesia or sedation procedures or other medical procedures. High-flow respiratory support has been found to be effective in meeting or exceeding the patient's normal inspiratory demands, enhancing patient oxygenation, reducing the work of breathing, and providing transnasal humidified rapid-flow ventilation exchange (THRIVE). Preoxygenation using a high-flow system prior to administration of anesthesia or sedation provides an oxygen reservoir and extends safe apneic time. Additionally, a flushing effect can be created in the nasopharynx such that the anatomical dead space in the upper airway is flushed by the incoming high-flow gas stream. This provides a reservoir of fresh gas available for every breath while minimizing rebreathing of carbon dioxide, nitrogen, etc. THRIVE is the provision of a high flow of respiratory gas to the patient when the patient is apneic, occurring when the anesthetic has taken effect and before the patient has been successfully intubated and mechanically ventilated. High-flow respiratory assistance refers to the delivery of heated and humidified respiratory gases to a patient through a non-sealing patient interface (such as a nasal cannula) generally at high flow rates intended to meet or exceed the patient's inspiratory demands when the patient is breathing spontaneously.

[0005] Once preoxygenation has been performed, an anesthetic drug is delivered to the patient to sedate the patient prior to intubation. After intubation, an anesthetic drug is also delivered to maintain the patient in an anesthetized state during the medical procedure. This delivery of an anesthetic drug can be via injection or aerosol / vapor, the latter of which can be achieved by using an anesthesia machine. A system configured for an anesthesia procedure typically includes an anesthesia machine that includes a rebreathing system in which exhaled gases from the patient are returned to the anesthesia machine. The anesthesia machine provides an anesthetic drug to sedate and / or keep the patient sedated via a sealed mask placed over the patient. Once sedated, the patient is intubated and mechanically ventilated (anesthesia ventilation) by the anesthesia machine that assists or replaces spontaneous breathing.

[0006] Reference herein to a patent document, or any other matter identified as prior art, should not be construed as an admission that the document or other matter was known or that the information contained in the document or other matter was part of the common general knowledge at the priority date of any of the claims. Summary of the Invention [Problem to be solved by the invention]

[0007] Currently, high-flow systems and anesthesia machines are separate systems, and there is no easy, effective, and safe way to integrate both systems and / or their functions into the delivery of anesthesia. This makes it difficult to efficiently and safely transition from one form of respiratory support to the other during medical procedures that require the use of both devices. It would be useful to resolve or ameliorate one or more of these difficulties. [Means for solving the problem]

[0008] Viewed from one aspect, the present disclosure provides a system for delivering respiratory gas to a patient, the system comprising: (a) a first breathing apparatus configurable to deliver a breathing gas comprising one or more anesthetic agents to a patient; (b) a second breathing apparatus configurable to deliver breathing gas to the patient at a predetermined flow rate; (c) switching means operable to select an operating mode of the system, said operating mode comprising: (i) a first mode in which breathing gas is delivered to a patient by a first breathing apparatus; (ii) a second mode in which breathing gas is delivered to the patient by a second breathing apparatus; and A switching means selected from the group including: Includes.

[0009] Typically, in the second mode of operation, the breathing gas delivered to the patient excludes the anesthetic agent.

[0010] In some embodiments, when the first mode is selected, the system directs the flow of breathing gas to a first inhalation flow path, where the first patient interface directs the breathing gas into the patient's airway and is a sealing interface. Preferably, the first patient interface directs exhaled gas from the patient to an exhalation flow path that returns the exhaled gas to the first inhalation flow path via the first respiratory device. The first patient interface may be a sealing mask or an endotracheal tube.

[0011] In some embodiments, when the second mode is selected, the system isolates the flow of breathing gas from the first breathing device to prevent delivery of anesthetic to the patient. Preferably, when the second mode is selected, the system directs the flow of breathing gas to a second inspiratory flow path, where a second patient interface directs breathing gas to the patient's airway and is a non-sealing interface, such as a nasal cannula.

[0012] In some embodiments, the switching means includes a switching mechanism configured to alter the flow of breathing gas within the system according to selection of the first or second operating mode. The switching mechanism may be located between the gas supply and the first and second breathing devices. In some embodiments, the switching mechanism includes one or more gas flow valves.

[0013] In some embodiments, the switching mechanism includes a gas delivery device that receives a supply of gases including NO, O2, and air and has one or more respiratory gas outlets. The gas delivery device can include one or more flow meters that control the flow of gases including one or more of NO, O2, and air through the one or more respiratory gas outlets. The one or more flow meters can control the flow of respiratory gas through the one or more respiratory gas outlets in response to a selection of the first or second operating mode.

[0014] In some embodiments, the gas delivery device includes a gas mixing element that mixes NO, O2, and air in the proportions required for operation of the system in the first mode.

[0015] In some embodiments, the gas delivery device includes a common gas outlet for supplying breathing gas from the gas delivery device to the first and second breathing devices. The gas delivery device may include a first switching element coupled to the switching means and operable to control the input to the common gas outlet; (i) when the first mode is selected, the common gas outlet receives breathing gas from the gas mixing element; (ii) When the second mode is selected, the common gas outlet receives breathing gas from the flow meter.

[0016] In some embodiments, the first and second respiratory devices may be integrated into an integrated machine. The integrated machine may include a humidifier configured to condition the respiratory gas to a predetermined temperature and / or humidity before delivery to the patient in the second mode. The humidifier may be located between the second respiratory device and the second patient interface.

[0017] In some embodiments, the gas delivery device includes a gas mixing element that mixes NO, O2, and air in the proportions required for operation of the system in the first or second mode, and may further include a flow meter that controls the flow rate of breathing gas from the gas mixing element. a first gas outlet for supplying breathing gas from the gas delivery device to the first breathing apparatus; a second gas outlet for supplying breathing gas from the gas delivery device to a second breathing apparatus; a first switching element coupled to the switching means and operable to prevent flow of NO to the gas mixing element when the second mode is selected; may include.

[0018] In some embodiments, the system further includes a second switching element coupled to the switching means and operable to control gas flow from the gas delivery device to the first and second breathing devices, such that (i) when the first mode is selected, breathing gas from the gas delivery device is directed only to the first gas outlet, and (ii) when the second mode is selected, breathing gas from the gas delivery device is directed only to the second gas outlet.

[0019] In some embodiments, the gas delivery device includes a first switching element operable to allow a flow of respiratory gas from the gas delivery device to the first respiratory device when the first mode is selected. The second respiratory device can include a flow meter that receives a supply of gas including O2 to deliver at a predetermined flow rate, and the system can include a second switching element operable to allow a flow of respiratory gas from the flow meter to the second patient interface when the second mode is selected. The first switching element and the second switching element can be operably coupled such that when the second mode is selected, the first switching element blocks the flow of respiratory gas from the gas delivery device to the first respiratory device and the second switching element allows the flow of respiratory gas from the flow meter to the second patient interface.

[0020] In some embodiments, the switching mechanism includes a gas diverter that receives a supply of gas including anaesthetic gas and respiratory gas, the gas diverter having first and second switching elements operable to control the flow of gas from the gas diverter to the first and second respiratory devices according to selection of a first or second operating mode of the system. The first switching element can include a valve that opens in the first mode and closes in the second mode to control the flow of anaesthetic gas. The second switching element can include one or more diverter valves that direct respiratory gas to the first respiratory device in the first mode and direct respiratory gas to the second respiratory device in the second mode.

[0021] In some embodiments, the switching mechanism includes (a) a first switching element operable to direct the flow of O2 to the first breathing device in the first mode and to the second breathing device in the second mode, and (b) a second switching element responsive to the first switching element and operable to stop the flow of gas from the first device to the patient when the first switching element operates in the second mode. The first switching element can be, for example, a flow diverter valve.

[0022] In some embodiments, the first and second breathing apparatus are separate machines. The second breathing apparatus may include a humidifier configured to condition the breathing gas to a predetermined temperature and / or humidity before delivery to the patient in the second mode.

[0023] In some embodiments, the first switching element and the second switching element are operatively linked to operate substantially simultaneously with or subsequent to operation of the switching means, hi other embodiments, the switching means incorporates the first and second switching elements.

[0024] In some embodiments, the predetermined flow rate is selectable by a user operating the switching means from an available range of about 20 L / min to about 90 L / min. In some embodiments, the predetermined flow rate is selectable by a user from a plurality of predetermined available flow rates. The predetermined available flow rates may include at least, for example, 0 L / min, 40 L / min, and 70 L / min.

[0025] In some embodiments, the switching means is user operable to select delivery of a selected pre-determined flow rate in a continuous or oscillatory flow. The switching means may include a flow rate selector user operable to control the selection and / or delivery of the pre-determined flow rate in the second mode of operation. In some embodiments, operation of the flow rate selector prevents delivery of respiratory gas from the first breathing apparatus to the patient. In some embodiments, operation of the flow rate selector to select a flow rate of 0 L / min allows delivery of O2 to the first breathing apparatus, otherwise operation of the flow rate selector prevents delivery of anaesthetic agent from the first breathing apparatus to the patient.

[0026] In some embodiments the switching means comprises a pressure controlled actuator configured to allow the flow of breathing gas in the first breathing apparatus in response to an increase in breathing gas pressure in the flow to the second breathing apparatus, In some embodiments the switching means comprises a pressure controlled actuator configured to prevent the flow of breathing gas in the first breathing apparatus in response to a decrease in breathing gas pressure in the flow to the second breathing apparatus.

[0027] In some embodiments, the switching means further provides for user selection of a manual first mode of operation or a mechanical first mode of operation of the first respiratory device. For example, the switching means may include a three-way actuator that provides for user selection of a manual first mode of operation, a mechanical first mode of operation or a second mode of operation. Selection of the mechanical first mode may trigger the system to connect a mechanical ventilator circuit to the first respiratory device. Selection of the manual first mode may trigger the system to connect a ventilator bag to the first respiratory device.

[0028] In some embodiments, selection of the second operating mode causes the system to substantially simultaneously (i) block the flow of respiratory gas from the first respiratory device to the patient through the first inhalation flow path, and (ii) provide a flow of respiratory gas from the second respiratory device to the patient through the second inhalation flow path.

[0029] In some embodiments, the system includes a controller that receives input from one or more sensors that detect whether a breathing circuit coupled to a patient's airway is associated with a first patient interface for use with a first breathing device or a second patient interface for use with a second breathing device, and the controller operates the switching means to select an operating mode in accordance with the detected breathing circuit association.

[0030] The one or more sensors may include, for example, a pressure sensor arranged to measure back pressure in the first and / or second breathing apparatus, and the controller determines that the breathing circuit is associated with the first patient interface when the measured back pressure indicates that breathing gas is delivered to the patient by a substantially sealed patient interface. Alternatively or in addition, the one or more sensors may include a CO2 sensor associated with one or each of the first breathing circuit associated with the first patient interface and the second breathing circuit associated with the second patient interface, and the controller determines that the breathing circuit in which exhaled gas from the patient contains a high concentration of CO2 is the breathing circuit through which breathing gas is delivered to the patient. Alternatively or in addition, the sensor may include a proximity sensor.

[0031] In some embodiments, the switching means comprises one or more user operable actuators, the one or more actuators comprising one or more of a button, a switch, a knob, an electronic input device, a touch screen, a voice activated sensor and a foot operated switch. The one or more actuators may be located at or near a patient interface where respiratory gas is delivered to the patient by the first or second respiratory apparatus. In some embodiments, the one or more actuators comprise an electronic input device wirelessly coupleable to a controller of the system and positionable in a number of positions relative to the patient and / or the first and second respiratory apparatus.

[0032] The switching means may include one or more switching mechanisms, which may include one or more of mechanical, electronic, electromechanical, and pneumatic switching mechanisms. In some embodiments, the one or more switching mechanisms are connectable to the switching means via one or more of a wired and wireless coupling. The switching mechanism may be operable to control one or more characteristics of the respiratory gas delivered to the subject, the characteristics being selected from the group including the presence of volatile substances, flow rate, gas composition, gas concentration, temperature, and / or humidity.

[0033] In some embodiments, the second breathing apparatus is configured to deliver a flow of breathing gas at a predetermined flow rate that is in the range of approximately 20-90 L / min.

[0034] In some embodiments, operation of the system in the second mode eliminates the delivery of anesthetic agent in the breathing gas delivered to the patient. This can be accomplished using any suitable means.

[0035] The first breathing apparatus may include one or more of a CO2 absorber configured to treat returned exhaled gas in the first mode before recirculation to the patient, a pressure limiting valve configured to maintain a substantially stable pressure in the system in the first mode, a variable volume section for displacement of gas in the first mode, a fresh gas flow to supplement the anesthetic gas delivered to the patient in the first mode, and a vaporizer to vaporize a volatile anesthetic agent into the breathing gas delivered to the patient in the first mode.

[0036] The second breathing apparatus may include one or more of a flow source configured to generate a flow of gas through the system and a humidifier configured to condition the breathing gas to a predetermined temperature and / or humidity before delivery to the patient in the second mode.

[0037] Viewed from another aspect, the present disclosure provides a gas delivery device for use with a breathing system, the gas delivery device including (a) a first inlet for receiving a supply of anesthetic gas, (b) a second inlet for receiving a supply of breathing gas, (c) a first outlet, (d) a second outlet, and (e) a manifold between the first and second inlets and the first and second outlets, the manifold providing a first flow path to the first outlet and a second flow path to the second outlet, wherein the gas delivery device is operable in (i) a first configuration in which the first flow path is open and the second flow path is closed, and (ii) a second configuration in which the second flow path is open and the first flow path is closed.

[0038] In some embodiments, in a first configuration, the gas delivery device blocks the flow of anesthetic gas to the outlet. A first valve can control the flow of anesthetic gas in the manifold, where in the first configuration the first valve is open and directs the anesthetic gas to a first flow path, and in the second configuration the first valve is closed. A second valve can control the flow of respiratory gas in the manifold, where in the first configuration the second valve directs the respiratory gas to the first flow path, and in the second configuration the second valve directs the respiratory gas to the second flow path. One or both of the first and second valves can be operable to control the flow rate of gas therethrough.

[0039] In some embodiments, the gas delivery device includes a third inlet for receiving a further supply of breathing gas, the breathing gas supplied to the second and third inlets including air and O. The second valve may be operable to control the O concentration in the breathing gas delivered to the first and second flow paths.

[0040] In some embodiments, the gas delivery device is operable in a third configuration in which both the first flow path and the second flow path are open.

[0041] In some embodiments, the gas delivery device includes a switching means operable by a user to select a configuration for operation of the gas delivery device. The switching means may be pneumatic, mechanical, electronic, or a combination thereof.

[0042] In some embodiments, the gas delivery device can be configured to be connected to a power source, hi some embodiments, the gas delivery device can include a battery.

[0043] In some embodiments, the first outlet of the gas delivery device may be connectable to a first breathing apparatus gas inlet. The first breathing apparatus may be, for example, an anesthesia machine. In some embodiments, the second outlet of the gas delivery device may be connectable to a second breathing apparatus gas inlet. The second breathing apparatus may be, for example, a high-flow breathing apparatus.

[0044] The gas delivery apparatus may include one or more switching elements that create the first and second flow paths. The switching element may be located in the first breathing apparatus. The switching element may be located in the second breathing apparatus. The switching element may be located in a patient interface where breathing gas is directed to the patient's airway. The switching element may be activated in response to detection of a change in condition detected by one or more system sensors. The system sensors may include one of a pressure sensor, a CO2 sensor, an O2 sensor, a flow sensor, a gas concentration sensor, and the like. The switching element may communicate wired or wirelessly with one or more other switching elements to control operation of the gas delivery device according to a user selected configuration.

[0045] In some embodiments, the gas delivery device includes an output module that provides one or both of a visual and an audible indication of the configuration that the gas delivery device is operating in. Operation of the output module can be initiated, for example, when a user operates the switching means to select the second configuration.

[0046] In some embodiments, the gas delivery device includes a gas mixer that mixes the received gases in the ratio required to deliver the required therapy.

[0047] Viewed from another aspect, the present disclosure provides a respiratory apparatus operable to deliver respiratory gas to a patient in a plurality of modes, the respiratory apparatus providing an inhalation gas flow path and an exhalation gas flow path, (a) in a first mode, the respiratory apparatus delivers respiratory gas comprising one or more anesthetic agents to the inhalation gas flow path and receives exhalation gas return via the exhalation gas flow path, (b) in a second mode, the respiratory apparatus disables the flow of one or more anesthetic agents and delivers respiratory gas comprising O2 at a predetermined flow rate to the inhalation gas flow path without exhalation gas return, and (c) in a transient mode, the respiratory apparatus disables the flow of one or more anesthetic agents and delivers a high flow rate of O2 to the inhalation gas flow path.

[0048] The respiratory apparatus may include a switching means operable to select one of a plurality of modes of operation.

[0049] In some embodiments, the transient mode is activated only during operation of the actuator which is normally biased off. The respiratory apparatus may include a button or trigger configured to be activated by a user to operate the respiratory apparatus in the transient mode, with release of the button or trigger disabling the transient mode.

[0050] In some embodiments, in a first mode, the respiratory apparatus is operable to deliver respiratory gas containing an anesthetic agent to the patient by a first patient interface that forms a sealed interface with the patient's airway and returns exhaled gas to the respiratory apparatus by way of an exhaled gas flow path. The first patient interface may be a mask or an endotracheal tube.

[0051] In some embodiments, in the second mode, the respiratory apparatus is operable to deliver respiratory gas to the patient by means of a second patient interface that forms a non-sealing interface with the patient's airway. The second patient interface may be, for example, a nasal cannula.

[0052] In some embodiments, the breathing apparatus is operable in a first manual mode of operation or a first mechanical mode of operation. The breathing apparatus may include a switching means operable by a user to select between the first manual mode of operation, the first mechanical mode of operation or the second mode of operation. In some embodiments, selection of the first manual mode triggers connection of a manual ventilation bag to the first breathing apparatus.

[0053] In some embodiments, the respiratory apparatus can be configured in gas flow communication with one or more of: a CO2 absorber configured to treat returned exhaled gases in the first mode before recirculation to the patient; a pressure limiting valve configured to maintain a substantially stable pressure in the system in the first mode; a variable volume for displacement of gas in the first mode; a fresh gas flow to replenish the anesthetic gas delivered to the patient in the first mode; and a vaporizer to vaporize a volatile anesthetic agent into the respiratory gas delivered to the patient in the first mode.

[0054] In some embodiments, the respiratory apparatus can be configured in gas flow communication with one or more of a flow source configured to generate a gas flow through the system and a humidifier configured to condition the respiratory gas to a predetermined temperature and / or humidity before delivery to the patient in the second mode.

[0055] Viewed from another aspect, the present disclosure provides a system for delivering respiratory gas to a patient, the system receiving a supply of respiratory gas for delivery to the patient by an inspiratory gas flow path and connectable to a return gas conduit for returning exhaled gas from the patient, the system including a flow generator configured to generate a gas flow through the system and a switching actuator operable to select an operating mode of the system, the system operable in a first mode in which the respiratory gas is delivered in a closed gas flow circuit in which the exhaled gas is returned to the system for rebreathing by the patient, and a second mode in which the respiratory gas is delivered in an open gas flow circuit without rebreathing.

[0056] In some embodiments, the flow generator is a blower operable to deliver a gas flow at a flow rate suitable for delivering respiratory therapy, including anesthesia, ventilation, and high-flow respiratory support. The flow generator may be operable to deliver a gas flow in the range of up to about 90 L / min.

[0057] In some embodiments, the switching actuator is operatively coupled to the flow generator, and operation of the switching actuator to select the first mode causes operation of the flow generator at a low flow rate, such as less than 15 L / min.

[0058] In some embodiments, the switching actuator includes or is operatively coupled to a switching mechanism, where in a first mode the switching mechanism allows a first fresh breathing gas flow to the system while allowing return of exhaled gas to the system, and in a second mode the switching mechanism allows the first fresh breathing gas flow to the system while preventing return of exhaled gas to the system. The switching mechanism can include any suitable mechanism, such as, for example, a gas flow diverter or a pressure controlled gas flow diverter.

[0059] In some embodiments, the switching mechanism is located upstream of the flow generator.

[0060] In some embodiments, the switching mechanism is operatively coupled to the flow generator, and operation of the switching mechanism in the first mode causes operation of the flow generator at a low flow rate.

[0061] The second mode may include a ventilator mode and a high-flow mode.

[0062] In some embodiments, operation of the switch actuator to select the high flow mode causes operation of the flow generator at a flow rate sufficient to provide high flow respiratory assistance, hi some embodiments, operation of the switch actuator to select the ventilator mode causes operation of the flow generator at a flow rate consistent with patient ventilation.

[0063] In some embodiments, the system is configured to receive a supply of anesthetic gas for delivery to a patient in an inhalation gas flow path in a first mode. The system can include a pressure limiting valve that maintains a substantially stable gas pressure in the system. The system can be configured to receive the supply of anesthetic gas downstream of the flow generator or upstream of the flow generator. A return gas conduit can be connectable to the system downstream of the flow generator.

[0064] In some embodiments, the system includes a gas flow reflector, which may be configured, for example, to collect exhaled anesthetic gas from the patient and return it to the inhalation gas flow path during the subsequent inspiration phase.

[0065] The system may be configured to prevent the supply of anaesthetic gas to the system when the second mode is selected.

[0066] The system may include a CO2 absorber configured to treat the returned exhaled gas in the first mode before recirculation to the inhaled gas flow path. Alternatively or additionally, the system may include a humidifier configured to condition the respiratory gas to a predetermined temperature and / or humidity before delivery to the patient in the second mode.

[0067] Viewed from another aspect, the present disclosure provides a system for delivering respiratory gas to a patient, the system operable in a first mode and a second mode, the first mode including a recirculating gas flow between the system and the patient's airway, and the second mode including a non-recirculating gas flow between the system and the patient's airway, the system including: (a) a first module including a first set of respiratory components; and (b) a second module including a second set of respiratory components, the second module configured to cooperate with the first module to switch between the two modes, the system operable in the first mode when the first module is activated or coupled to the second module, and the system operable in the second mode when the first module is deactivated or coupled to the second module.

[0068] In a first mode, the gas delivered to the patient in the recirculating gas stream may contain an anaesthetic agent.

[0069] The first set of respiratory components may include one or more of a CO2 absorber configured to treat returned exhaled gases in the first mode before recirculation to the patient, a pressure limiting valve configured to maintain a substantially stable pressure within the system in the first mode, a variable volume section for displacement of gas in the first mode, a fresh gas flow to replenish the anesthetic gas delivered to the patient in the first mode, and a vaporizer to vaporize a volatile anesthetic agent into the respiratory gas delivered to the patient in the first mode.

[0070] The second set of respiratory components may include one or more of a flow source configured to generate a gas flow through the second set of respiratory components, an inhalation conduit, a patient interface configured to direct gas from the non-recirculated gas flow to the patient's airway, a humidifier configured to condition the respiratory gas to a predetermined temperature and / or humidity before delivery to the patient in the second mode, and a filter upstream of the patient interface.

[0071] The first module can include a first gas outlet and a first gas inlet, and the second module includes a second gas inlet and a second gas outlet, the first gas outlet being connectable to the second gas inlet, and the first gas inlet being connectable to the second gas outlet.

[0072] In some embodiments, operation of the system in a first mode allows a first fresh breathing gas flow into the system while allowing the return of exhaled gas to the system, and a second mode allows a first fresh breathing gas flow into the system while preventing the return of exhaled gas to the system.

[0073] In some embodiments, operation of the system in the second mode prevents release of anesthetic agent from the system. The second mode may include a ventilator mode and a high-flow mode.

[0074] The second module may be configured to receive a supply of breathing gas independent of the first module.

[0075] Viewed from another aspect, the present disclosure provides a system for delivering respiratory gas to a patient, the system including a flow source configured to generate a gas flow through the system in a gas delivery circuit, and a switching mechanism forming part of the gas delivery circuit, the gas delivery circuit having an inspiratory gas flow path and an expiratory gas flow path, the switching mechanism configured to switch the gas flow paths in the gas delivery circuit according to selection of a first operating mode in which the inspiratory gas flow path is in fluid communication with a first patient interface, or a second operating mode in which the inspiratory gas flow path is in fluid communication with a second patient interface.

[0076] The first patient interface is capable of forming a substantially sealed interface with the patient's airway and receives exhaled gases from the patient, and the second patient interface is capable of forming a non-sealing interface with the patient's airway.

[0077] In some embodiments, the switching mechanism includes one or more of a gas flow diverter, a bi-stable switch, a pneumatic switch, a rotary switch, a lever, a knob, or other user-operable actuator. The switching mechanism may be user-operable to switch between inspiratory and expiratory gas flows in the gas delivery circuit.

[0078] In some embodiments, the system includes one or more sensors configured to monitor one or more characteristics of the gas in the gas delivery circuit and controls operation of the flow generator based on the one or more monitored characteristics. The characteristics may be indicative of one or more of flow rate, pressure, and CO2, to name a few. In some embodiments, the system controls operation of the flow source to generate a low flow rate when the one or more sensors indicate that the respiratory gas flow is to the first patient interface. In some embodiments, the system controls operation of the flow generator to generate a high flow rate when the one or more sensors indicate that the respiratory gas flow is to the second patient interface.

[0079] In some embodiments, the system is configured to receive a user input to select a first mode of operation in which the flow source generates a low flow rate below a predetermined flow rate or a second mode of operation in which the flow source generates a high flow rate at or above a predetermined flow rate, and the switching mechanism operates in response to a flow rate of gas in the inhalation gas flow path generated by the flow source. The switching mechanism can direct flow to the first patient interface in response to a low flow rate of gas in the inhalation gas flow path. The switching mechanism can direct flow to the second patient interface in response to a high flow rate of gas in the inhalation gas flow path.

[0080] In some embodiments, the switching mechanism is provided by operation of the first and second patient interfaces, where the first delivery mode is selected when the first and second patient interfaces are simultaneously applied to the patient, and the second delivery mode is selected when only the second patient interface is applied to the patient. In some embodiments, the first patient interface is a sealing face mask and the second patient interface is a nasal cannula adapted to operate, including while the sealing face mask is applied over the nasal cannula. Thus, the first patient interface may be a mask configured to form a sealing interface over the second patient interface, which is a nasal cannula. In some embodiments, the sealing face mask is not operable when the sealing face mask is not applied over the nasal cannula, and the second delivery mode is enabled when only the nasal cannula is applied to the patient.

[0081] In some embodiments, simultaneous use of the first patient interface and the second patient interface in the first mode directs inspiratory gas flow to the patient by one or both of the first and second patient interfaces and returns expiratory gas from the first patient interface to the expiratory gas flow path.

[0082] In some embodiments, the first patient interface is in fluid communication with the anesthetic gas reflector.

[0083] In some embodiments, the system may include one or more of a CO2 absorber configured to treat returned exhaled gas in the first mode before recirculation to the patient, a pressure limiting valve configured to maintain a substantially stable pressure within the system in the first mode, a variable volume section for displacement of gas in the first mode, a fresh gas flow to supplement the anesthetic gas delivered to the patient in the first mode, and a vaporizer to vaporize a volatile anesthetic agent into the breathing gas delivered to the patient in the first mode.

[0084] In some embodiments, the system includes one or more of a flow source configured to generate a gas flow through the system and a humidifier configured to condition the respiratory gas to a predetermined temperature and / or humidity before delivery to the patient in the second mode.

[0085] Viewed from another aspect, the present disclosure provides a switching mechanism forming part of a gas delivery circuit for delivering respiratory gas to a patient, the switching mechanism configured to switch between an inhaled gas flow path and an exhaled gas flow path in the gas delivery circuit according to selection of a first operating mode in which the inhaled gas flow path is in fluid communication with a first patient interface, or a second operating mode in which the inhaled gas flow path is in fluid communication with a second patient interface.

[0086] In some embodiments, the switching mechanism may be user operable and may include one or more of a gas flow diverter, a pneumatic switch, a rotary switch, a lever, a knob, or other user operable actuator.

[0087] In some embodiments, the switching mechanism can operate in response to a flow rate of gas in the intake flow path, where the second mode of operation is selected when the flow rate of gas is high. In some embodiments, the switching mechanism can be configured to operate in response to a flow rate of gas in the intake flow path, where when the flow rate of gas is low the switching mechanism switches to the first mode of operation and when the flow rate of gas is high the switching mechanism switches to the second mode of operation.

[0088] Viewed from another aspect, the present disclosure provides a multi-lumen assembly for use with a respiratory assistance system, the multi-lumen assembly having a plurality of conduits including (a) a first inhalation conduit having a first conduit inlet end connectable to a first gas outlet of the respiratory assistance system, (b) a second inhalation conduit having a second conduit inlet end connectable to a second gas outlet of the respiratory assistance system, and (c) an expiratory conduit having an expiratory conduit outlet end connectable to an expiratory gas inlet of the respiratory assistance system.

[0089] The first inhalation conduit may have a first conduit outlet end coupleable to a first patient interface configured for sealing engagement with and directing flow into the patient's airway, and the second inhalation conduit may have a second conduit outlet end coupleable to a second patient interface configured for directing flow into the patient's airway, the second conduit being a non-sealing interface.

[0090] In some embodiments, at least a portion of the multiple conduits may be coaxially arranged.

[0091] A mechanism may be provided for holding at least a portion of the plurality of conduits in a mass. The mechanism may include webbing spaced or continuously disposed along at least a portion of the plurality of conduits between at least pairs of the plurality of conduits. The webbing may be breakable to facilitate separation of at least a portion of one or more of the plurality of conduits from the mass. Alternatively or additionally, the mechanism may include a sheath applied around the plurality of conduits. A portion of the sheath may be removable. The sheath may provide a smooth outer surface. Alternatively or additionally, the mechanism may include one or more retainers configured to hold two or more conduits in the plurality of conduits in a mass. The retainer may be slidable along a portion of one or more of the conduits in the plurality of conduits.

[0092] In some embodiments, the first inhalation conduit can be configured to deliver respiratory gas containing an anesthetic agent to the patient. The exhalation conduit can be configured to return exhaled gas from the patient to the respiratory assistance system. The second inhalation conduit can be configured to deliver respiratory gas to the patient at a flow rate between 20 L / min and 90 L / min.

[0093] In some embodiments, the multi-lumen assembly may include or cooperate with a flow switching mechanism operable to direct the flow of breathing gas into the first inhalation conduit or into the second inhalation conduit. The flow switching mechanism may be a flow diverter. The flow switching mechanism may be operable by a user. Alternatively or additionally, the flow switching mechanism may be operatively coupled to a respiratory assistance system controller. In some embodiments, the respiratory assistance system controller controls the respiratory assistance system to deliver breathing gas to the multi-lumen assembly according to the operation of the flow switching mechanism by the user. The respiratory assistance system controller may control the operation of the flow switching mechanism.

[0094] In some embodiments, the outlet end of the first inhalation conduit and the inlet end of the expiratory conduit form a common gas flow path defined by a single gas exchange conduit connectable to the first patient interface, which may be tapered to reduce the overall cross section of the multi-lumen assembly in the region of the single gas exchange conduit.

[0095] In some embodiments, the multi-lumen assembly includes a patient-end connector that (a) couples an outlet end of the first inhalation conduit with a first patient interface and (b) couples an outlet end of the second inhalation conduit with a second patient interface. The patient-end connector may include a switching element operable to switch the connector between a first mode of operation in which the connector directs respiratory gas to the first patient interface and a second mode of operation in which the connector directs respiratory gas to the second patient interface. The switching element may be operatively couplable with a respiratory assistance system controller. Alternatively or in addition, the switching element may be operable by a user, and the controller controls operation of the respiratory assistance system according to operation of the switching element by the user. In some embodiments, the respiratory assistance system controller controls operation of the switching element.

[0096] In some embodiments, the multi-lumen assembly can include a gas sampling conduit for monitoring one or more characteristics of the gas that can be used by a respiratory assistance system controller to determine whether the connector is delivering respiratory gas to the patient in the first inhalation conduit or the second inhalation conduit, and the controller can operate the respiratory assistance system to automatically select a corresponding operating mode of the respiratory assistance system.

[0097] Viewed from another aspect, the present disclosure provides a respiratory gas connector for use with a respiratory assistance system for delivering respiratory gas to a patient, the connector having (a) an inlet port connectable to a gas flow conduit receiving respiratory gas from the respiratory assistance system, (b) a first outlet port connectable to a first gas flow path for delivering respiratory gas to the patient via a first patient interface, (c) a second outlet port connectable to a second gas flow path for delivering respiratory gas to the patient via a second patient interface, and (d) a switching mechanism operable to switch the connector between a first operating mode in which the connector directs gas from the inlet port to the first outlet port and a second operating mode in which the connector directs gas from the inlet port to the second outlet port.

[0098] In some embodiments, the connector can include an expiratory gas port coupleable with an expiratory gas conduit, and in a first mode, the switching mechanism directs expiratory gas in the first gas flow path to the expiratory gas conduit.

[0099] The switching mechanism may be operatively coupled to a controller of the respiratory assistance system. Manipulation of the connector switching mechanism may select: (a) a first operating mode causing the controller to operate the respiratory assistance system in a first mode in which respiratory gas including an anesthetic agent is delivered to a gas flow conduit coupled to the connector; and (b) a second operating mode causing the controller to operate the respiratory assistance system in a second mode in which respiratory gas is delivered at a predetermined flow rate to a gas flow conduit coupled to the connector.

[0100] In some embodiments, the connector switching mechanism can be operatively coupled to a controller of the respiratory assistance system, such that operation of the connector switching mechanism to select the second operating mode can cause the controller to block the flow of anesthetic agent in the respiratory gas.

[0101] In some embodiments, the connector may include a sensor that detects one or more characteristics of the gas at the first or second outlet port, the characteristics being used to determine whether the connector is coupled to a patient's airway by a first or second patient interface, and the sensor providing an input to a controller of the respiratory assistance system that automatically selects a corresponding operating mode of the respiratory assistance system. The one or more characteristics may include, for example, gas pressure, CO2 concentration, gas flow rate, etc.

[0102] In some embodiments, the sensor wire may be positionable within a conduit that provides a gas flow path between the sensor and the respiratory assistance system controller.

[0103] Viewed from another aspect, the present disclosure provides a controller for use with a respiratory assistance system for supplying respiratory gas to a patient via a multi-lumen assembly, the controller including: (a) a control interface operable to receive a user selection of a first or second operating mode of the respiratory assistance system; (b) a tube assembly input connector for connecting to a patient end of a multi-lumen assembly having a first inhalation conduit, a second inhalation conduit and an expiratory conduit; (c) a first flow port connectable to a first flow path for delivering respiratory gas to the patient in the first mode; and (d) a second flow port connectable to a second flow path for delivering respiratory gas to the patient in the second mode.

[0104] In some embodiments, the controller can include a switching mechanism configured to direct breathing gas from a first inhalation conduit to a first flow port when a first mode is selected, and to direct breathing gas from a second inhalation conduit to a second flow port when a second mode is selected.

[0105] In some embodiments, the controller can include a third flow port coupleable to an exhalation flow path that receives exhaled gases from the patient in the second mode. The switching mechanism can be configured to direct exhaled gases to the third flow port when the second mode is selected.

[0106] In some embodiments, the controller may include an attachment means configured to releasably attach the controller to a structure located in proximity to the patient.

[0107] In some embodiments, the control interface may be operatively coupled to a respiratory assistance system controller. The respiratory assistance system controller may control the respiratory assistance system to deliver respiratory gas to the multi-lumen assembly as described above according to an operational mode selected using the control interface. In some embodiments, the respiratory assistance system controller is operable to control the operation of the control interface. The controller may be provided for use with a multi-lumen assembly as described above.

[0108] Viewed from another aspect, the present disclosure provides a system for delivering respiratory gas to a patient, the system operable to deliver respiratory gas via a first patient interface in a first mode and via a second patient interface in a second mode, the system including: (a) one or more CO2 sensors configured to detect CO2 in exhaled gas from the patient; (b) a switching mechanism for switching between the first mode and the second mode according to the detected CO2; and (c) a system controller that receives input from the one or more CO2 sensors, the system controller operating the switching mechanism to select the first mode or the second mode.

[0109] In some embodiments, the switching mechanism is operable to switch modes when at least a predetermined threshold of CO2 is detected. The threshold may be equivalent to, for example, the CO2 concentration of the ambient air.

[0110] The one or more switching mechanisms include one or more of mechanical, electronic, electromechanical, and pneumatic switching mechanisms. The one or more switching mechanisms may be coupled to the system controller via wired and / or wireless coupling.

[0111] In some embodiments, in the first mode, breathing gas is delivered to the patient's airway through a first patient interface, which may be a sealing interface such as a sealing mask or an endotracheal tube, and exhaled gas is returned to the system by an exhaled gas flow path. The first mode may include a rebreathing mode in which the exhaled gas returned to the system is recirculated for delivery to the patient through the first patient interface. The breathing gas may include one or more anesthetic agents. In some embodiments, a CO2 sensor detects CO2 in the exhaled gas in the exhaled gas flow path.

[0112] In some embodiments, the second mode is a high-flow mode in which breathing gas is delivered to the patient at a predetermined flow rate through a second patient interface, which is a non-sealing interface, such as a nasal cannula. A CO2 sensor can detect CO2 in the exhaled gases at the second patient interface as they exit the patient's airways. In some embodiments, the CO2 sensor can be located on the nasal cannula to detect CO2 in the exhaled gases exiting one or both of the patient's nasal passages.

[0113] In some embodiments, the system includes a first breathing apparatus that delivers respiratory gas in a first mode and a second breathing apparatus that delivers respiratory gas in a second mode. When the second mode is selected, the system can isolate the flow of respiratory gas from the first breathing apparatus to the patient. In some embodiments, the first and second breathing apparatus may be integrated into an integrated machine, although this is not required. In some embodiments, the system can include a humidifier configured to condition the respiratory gas to a predetermined temperature and / or humidity before delivery to the patient in the second mode.

[0114] In some embodiments, the second breathing apparatus delivers breathing gas at a predetermined flow rate, and optionally, the predetermined flow rate may be selectable from an available range of about 20 L / min to about 90 L / min by operating the switching means.

[0115] In some embodiments, the system includes a CO2 sensor associated with one or each of a first breathing circuit for delivery of respiratory gas in a first mode and a second breathing circuit for delivery of respiratory gas in a second mode. The controller can determine the breathing circuit having the highest concentration of CO2 to be the breathing circuit through which respiratory gas is delivered to the patient and can control the delivery of gas to the determined breathing circuit according to an associated mode of operation.

[0116] In some embodiments, the system includes a display device in operative communication with the system controller and configurable to display one or more CO2 O2 traces based on input from the one or more CO2 sensors received by the system controller. The system controller can be configured to automatically cause a single CO2 trace corresponding to a CO2 sensor input representing the highest detected CO2 from the multiple CO2 sensors to be displayed.

[0117] In some embodiments, the first breathing apparatus may include one or more of a CO2 absorber configured to treat returned exhaled gas in the first mode before recirculation to the patient, a pressure limiting valve configured to maintain a substantially stable pressure in the system in the first mode, a variable volume for displacement of gas in the first mode, a fresh gas flow to supplement the anesthetic gas delivered to the patient in the first mode, and a vaporizer to vaporize a volatile anesthetic agent into the breathing gas delivered to the patient in the first mode.

[0118] In some embodiments, the second breathing apparatus may include one or more of a flow source configured to generate a flow of gas through the system and a humidifier configured to condition the breathing gas to a predetermined temperature and / or humidity prior to delivery to the patient in the second mode.

[0119] Viewed from another aspect, the present disclosure provides a system for delivering respiratory gas to a patient, the system including: (a) a flow source configured to provide a gas flow through the system in a gas delivery circuit; and (b) a gas delivery conduit circuit including an inhalation gas flow path and an exhalation gas flow path, the system configured to switch between a first mode and a second mode. In the first mode, the system is operable to deliver respiratory gas to the patient via a first patient interface in fluid communication with the inhalation gas flow path and the inhalation gas flow path, and to deliver exhalation gas from the patient via a second patient interface in fluid communication with the exhalation gas flow path and the exhalation gas flow path, the respiratory gas comprising a first flow parameter. In the second mode, the system is operable to deliver respiratory gas to the patient via the inhalation gas flow path and the third patient interface, the respiratory gas comprising a second flow parameter.

[0120] In some embodiments, the first flow parameter is different from the second flow parameter. The first flow parameter can include a first flow rate and the second flow parameter can include a second flow rate, the first flow rate being less than the second flow rate. In some embodiments, the first flow rate is less than 15 L / min and the second flow rate is greater than 15 L / min. In some embodiments, the second flow rate is in the range of about 20 L / min to about 90 L / min, optionally about 40 L / min to about 70 L / min.

[0121] The first patient interface can include a non-sealing patient interface, such as a nasal cannula, and the second patient interface can include a sealing patient interface, such as a mask. The third patient interface can include a non-sealing patient interface, such as a nasal cannula. In some embodiments, the first patient interface and the third patient interface are the same.

[0122] In some embodiments, the exhalation flow path is inoperable in the second mode.

[0123] In some embodiments, the system is in a first mode when the first patient interface and the second patient interface are simultaneously applied to the patient and in a second mode when only the third patient interface is applied to the patient. The first and third patient interfaces can include non-sealing nasal cannulas and the second patient interface can include a sealing mask, and the system can be in the first mode when the nasal cannulas and the mask are applied to the patient and the system can be in the second mode when only the nasal cannula is applied to the patient. In some embodiments, the mask is configured to seal with the patient over the nasal cannulas.

[0124] In some embodiments, the system includes a third mode and a fourth patient interface, and the system can be configured to deliver breathing gas to the patient via the inhalation gas flow path and the fourth patient interface, and to deliver exhalation gas from the patient via the exhalation gas flow path and the fourth patient interface. The breathing gas can include a third flow parameter. The fourth patient interface can include a sealing patient interface, such as, for example, an invasive patient interface, a laryngeal mask, or an endotracheal tube.

[0125] In some embodiments, the first flow parameter comprises a pressure and / or a volume parameter.

[0126] In some embodiments, the third flow parameter includes one or more of a flow rate, a pressure, or a volume parameter.

[0127] In some embodiments, the system can be configured to control the delivery of breathing gas to the patient based on pressure and / or volume.

[0128] In some embodiments, the system includes an inhalation conduit defining at least a portion of an inhalation gas flow path, an expiratory conduit defining at least a portion of an expiratory gas flow path, and a common connector provided at ends of the inhalation conduit and the expiratory conduit, the common connector configured to connect to one or more patient interfaces.

[0129] In some embodiments, the system includes a controller in communication with the flow source and one or more of a sensor and an input interface in communication with the controller that provides input to the controller to control the flow source to provide a flow of respiratory gas in the first mode or the second mode. The sensor and / or the input interface can be configured to provide input to the controller to control the flow source to provide a flow of respiratory gas in a third mode.

[0130] In some embodiments, the system includes a humidifier, whereby the respiratory gas is heated and humidified by the humidifier before being delivered to the patient in the second mode.

[0131] In some embodiments, exhaled gas from the patient is returned to the inhalation gas flow path in a first mode. In some embodiments, in a third mode, exhaled gas from the patient is returned to the inhalation gas flow path. In some embodiments, the system includes a CO2 remover configured to remove CO2 from the exhaled gas before returning the exhaled gas to the inhalation gas flow path.

[0132] When a high-flow system is integrated with an anesthesia machine, it may be desirable to have a configuration that can easily and sufficiently humidify the respiratory gas delivered during high-flow respiratory assistance. It may also be desirable to allow for humidification of the respiratory gas in high-flow mode.

[0133] Viewed from another aspect, the present disclosure provides a respiratory apparatus for delivering respiratory gas to a patient, the respiratory apparatus including a flow source providing a flow of respiratory gas in an inhalation flow path for delivery to the patient, a mount coupled to at least one vaporizer for vaporizing one or more volatile anesthetic agents into the flow of respiratory gas in the inhalation flow path prior to delivery to the patient, and a return flow path for recirculating exhaled gas received from the patient via the exhalation flow path to the inhalation flow path, the mount being connectable to a humidification component for conditioning the flow of respiratory gas in the inhalation flow path to a predetermined temperature and / or humidity prior to delivery to the patient.

[0134] In some embodiments, operation of the humidification component prevents delivery of one or more volatile anesthetic agents into the flow of breathing gas in the inspiratory flow path. Operation of the humidification component can disable operation of at least one vaporizer.

[0135] In some embodiments, the respiratory apparatus further includes an interlocking mechanism that prevents simultaneous operation of the humidification component and the at least one vaporizer. The interlocking mechanism may be configured to enable operation of the humidification component or the at least one vaporizer when in the unlocked configuration and to disable operation of the humidification component or the at least one vaporizer when in the locked configuration.

[0136] The humidification component and the at least one vaporizer can be configured to cooperate with one another to provide an interlocking mechanism. The humidification component and the at least one vaporizer can be mountable adjacent one another on the respiratory apparatus. For example, the mount can include a plurality of slots for coupling with the humidification component and the at least one vaporizer in a side-by-side arrangement. The slots can be configured to receive a housing of the humidification component and a housing of the at least one vaporizer. The mount can be configured to receive a housing of the humidification component and a housing of the at least one vaporizer by sliding engagement with the slots.

[0137] In some embodiments, the humidification component and the at least one vaporizer can each include a locking element associated with its housing. The locking element can be configured to engage with a corresponding locking element associated with the housing of the other of the humidification component and the at least one vaporizer to provide an interlocking mechanism. The locking element can include at least one locking pin that is retractable within the housing in a locked configuration and extendable from the housing in an unlocked configuration. The locking element can include two or more locking pins, each independently retractable within the housing in a locked configuration and extendable from the housing in an unlocked configuration.

[0138] In some embodiments, the humidification component and the at least one vaporizer include slots associated with their housings, and the at least one locking pin is slidably moveable between the slots of the humidification component and the at least one vaporizer to provide an interlocking mechanism. In a locked configuration, the at least one locking pin may be positionable with a slot of the humidification component or the at least one vaporizer. In an unlocked configuration, the at least one locking pin may be positionable within a slot of the other of the humidification component or the at least one vaporizer.

[0139] In some embodiments, the respiratory apparatus further includes a switching mechanism configured to enable selective operation of the humidification component and the at least one vaporizer, such that activation of the switching mechanism to operate the humidification component or the at least one vaporizer can prevent the other of the humidification component and the at least one vaporizer from operating until the switching mechanism is deactivated.

[0140] The switching mechanism can include at least one vaporizer and each of the humidification components operable by a switch, and the switches can be coupled to each other to prevent simultaneous operation of the humidification component and the at least one vaporizer.

[0141] In some embodiments, the switching mechanism is coupled with a linkage mechanism such that upon activation of the switching mechanism to operate the humidification component or the at least one vaporizer, the linkage mechanism can enable operation of the humidification component or the at least one vaporizer and can disable operation of the other of the humidification component or the at least one vaporizer.

[0142] In some embodiments, the humidification component includes a humidification chamber through which the respiratory gas is received and conditioned to a predetermined temperature and / or humidity. The humidification chamber can be configured to couple with the mount. A housing of the humidification chamber can be configured to be slidably received on the mount. For example, the mount can include a plurality of slots, and the housing of the humidification chamber can be slidably received in one of the slots.

[0143] The mount may include a heating element to heat the liquid in the humidification chamber. The humidification chamber may include a conductive plate to conduct heat from the heating element in the mount. In other embodiments, the humidification chamber includes a heating element to heat the liquid in the humidification chamber. The humidification chamber may be configured to be in electrical communication with the respiratory apparatus for operation of the humidification chamber.

[0144] In some embodiments, the humidification component includes a humidifier having a humidification chamber, the humidification chamber being connectable to a humidification base unit for operation of the humidification chamber. The humidification base unit can be configured to be connected to a mount. The housing of the humidification base unit can be configured to be slidably received on the mount. For example, the mount can include a plurality of slots, and the housing of the humidification base unit can be slidably received in one of the slots. The humidification base unit can include a heating element to heat a liquid in the humidification chamber.

[0145] A humidification chamber as disclosed herein may include an inlet port for receiving a flow of respiratory gas from a breathing apparatus and an outlet port for delivering a conditioned flow of respiratory gas to a patient. The outlet port may be connectable to an inhalation conduit to deliver the conditioned flow of respiratory gas to the patient via a patient interface.

[0146] In other embodiments, a humidification chamber as disclosed herein may include an inlet port for receiving a flow of respiratory gas from a breathing apparatus and a return port for returning the flow of conditioned respiratory gas to the breathing apparatus. The return port may be connectable to the breathing apparatus to return the flow of conditioned respiratory gas to the breathing apparatus.

[0147] In some embodiments, the humidification chamber includes a liquid inlet that connects to a liquid reservoir for refilling the humidification chamber. The humidification chamber can include a flow control mechanism that controls the flow of liquid into the humidification chamber. The humidification chamber can include at least one sensor that detects the level of liquid in the humidification chamber. The humidification chamber can include a float valve that controls the level of liquid in the humidification chamber.

[0148] In some embodiments, the humidification component is coupleable to the mount via an adapter. The adapter can include a first inlet port for receiving a flow of respiratory gas from the breathing apparatus and a first outlet port for delivering the flow of respiratory gas to the humidification component. The adapter can further include a second inlet port for receiving a flow of conditioned respiratory gas from the humidification component. The adapter can also include a second outlet port for delivering the flow of conditioned respiratory gas from the humidification component to the breathing apparatus.

[0149] In some embodiments, the adapter is configured to electrically connect to a respiratory apparatus for operation of the humidification component. The adapter may include a first power connector that provides electrical connection with the respiratory apparatus. The adapter may also include a second power connector that provides electrical connection with the humidification component.

[0150] The respiratory apparatus can be configured to operate in the following modes of operation: a first mode in which the respiratory apparatus delivers respiratory gas to the inhalation flow path and receives return of exhaled gas via the exhalation flow path, and a second mode in which the respiratory apparatus delivers respiratory gas to the inhalation flow path at a predetermined flow rate without return of exhaled gas from the patient.

[0151] In some embodiments, the respiratory apparatus is further configured to detect coupling of the humidification component to the mount to enable operation of the respiratory apparatus in the second mode. For example, the mount may include a sensor to detect coupling of the humidification component. In the second mode, the humidification component may be operable to condition the flow of respiratory gas in the inspiratory flow path to a predetermined temperature and / or humidity prior to delivery to the patient.

[0152] In some embodiments, the respiratory apparatus further includes a CO2 absorber configured to treat exhaled gas returned from the patient in the first mode before recirculation to the patient. In the second mode, the CO2 absorber can be further configured to condition the respiratory gas in the inhalation flow path to a predetermined temperature and / or humidity before delivery to the patient. In the second mode, the CO2 absorber can be configured to condition the respiratory gas to a predetermined temperature and / or humidity by one or both of modifying the amount of soda lime present in the CO2 absorber and modifying the amount of CO2 provided to the soda lime present in the CO2 absorber.

[0153] In a first mode, the respiratory apparatus may be operable to deliver respiratory gas to the patient by a first patient interface that forms a sealed interface with the patient's airway and returns exhaled gas to the respiratory apparatus via an exhalation flow path. In the first mode, the respiratory gas includes one or more anaesthetic agents. The first patient interface may be a mask or an endotracheal tube.

[0154] In a second mode, the respiratory apparatus may be operable to supply respiratory gas to the patient by a second patient interface that forms a non-sealing interface with the patient's airway. The second patient interface may be a nasal cannula.

[0155] In the second mode, the predetermined flow rate can be in the range of about 20 L / min to about 90 L / min.

[0156] In the second mode, the predetermined flow rate can be in the range of about 40 L / min to about 70 L / min.

[0157] In some embodiments, the respiratory apparatus can be configured to be in gas flow communication with a gas delivery apparatus that receives a supply of gas including NO, O2, and air. The gas delivery apparatus can include a gas mixing element that mixes one or more of NO, O2, and air in a ratio required to deliver respiratory gas in the first mode and / or the second mode, and a gas outlet that supplies gas from the gas delivery apparatus to the respiratory apparatus.

[0158] In some embodiments, the respiratory apparatus can be configured to be in gas flow communication with a flow meter that controls the flow of gas including one or both of air and O2 in the second mode.

[0159] In some embodiments, the respiratory apparatus can be configured in gas flow communication with one or more of: a pressure limiting valve configured to maintain a substantially stable pressure within the respiratory apparatus in the first mode; a variable volume section for displacement of gas in the first mode; a fresh gas flow to supplement the respiratory gas delivered to the patient in the first mode; and a vaporizer to vaporize one or more volatile anesthetic agents into the flow of respiratory gas before delivery to the patient in the first mode.

[0160] In another aspect, the disclosure provides a humidification component for use with a respiratory apparatus for delivering respiratory gas to a patient, the respiratory apparatus including a flow source providing a flow of respiratory gas to an inhalation flow path for delivery to the patient, a mount for coupling with at least one vaporizer for vaporizing one or more volatile anesthetic agents into the flow of respiratory gas in the inhalation flow path prior to delivery to the patient, and a return flow path for recirculating exhaled gases received from the patient via the exhalation flow path to the inhalation flow path, the humidification component being coupleable with the mount to condition the flow of respiratory gas in the inhalation flow path to a predetermined temperature and / or humidity prior to delivery to the patient.

[0161] In some embodiments, operation of the humidification component prevents delivery of one or more volatile anesthetic agents into the flow of breathing gas in the inspiratory flow path. Operation of the humidification component can disable operation of at least one vaporizer.

[0162] In some embodiments, the humidification component is coupleable with the mount to provide an interlocking mechanism that prevents simultaneous operation of the humidification component and the at least one vaporizer. The interlocking mechanism can be configured to enable operation of the humidification component or the at least one vaporizer when in the unlocked configuration and to disable operation of the humidification component or the at least one vaporizer when in the locked configuration.

[0163] The humidification component may be connectable with the mount to cooperate with the at least one vaporizer to provide an interlocking mechanism. The humidification component may be mountable on the respiratory apparatus adjacent to the at least one vaporizer. For example, the mount may include a plurality of slots for connecting with the humidification component and the at least one vaporizer in a side-by-side arrangement. The slots may be configured to receive a housing of the humidification component and a housing of the at least one vaporizer. The mount may be configured to receive a housing of the humidification component and a housing of the at least one vaporizer by sliding engagement with the slots.

[0164] In some embodiments, the humidification component includes a housing having a locking element configured to engage a corresponding locking element associated with the at least one vaporizer housing to provide an interlocking mechanism. The locking element can include at least one locking pin that is retractable within the housing in a locked configuration and extendable from the housing in an unlocked configuration. The locking element can include two or more locking pins, each independently retractable within the housing in a locked configuration and extendable from the housing in an unlocked configuration.

[0165] In some embodiments, the humidification component includes a housing having a slot, and the at least one locking pin is slidably movable between the slot of the humidification component and a slot associated with the housing of the at least one vaporizer to provide an interlocking mechanism. The at least one locking pin may be positionable within the slot of the humidification component in a locked configuration. The at least one locking pin may be positionable within the slot of the at least one vaporizer in an unlocked configuration.

[0166] In some embodiments, the respiratory apparatus further includes a switching mechanism configured to enable selective operation of the humidification component and the at least one vaporizer, where activation of the switching mechanism to operate the humidification component can prevent operation of the at least one vaporizer until the switching mechanism is deactivated.

[0167] The switching mechanism can include a humidification component operable by a switch, and the switch can be coupled to a switch of the at least one vaporizer to prevent simultaneous operation of the humidification component and the at least one vaporizer.

[0168] The humidification component may further include a user-operable switch to enable selective operation of the humidifier. For example, the switch may be a manually operated switch, such as a button or dial on the housing of the humidification component.

[0169] In some embodiments, the switching mechanism is coupled to an interlocking mechanism such that upon activation of the switching mechanism to operate the humidification component, the interlocking mechanism can enable operation of the humidification component and disable operation of the at least one vaporizer.

[0170] In some embodiments, the humidification component includes a humidification chamber through which the respiratory gas is received and conditioned to a predetermined temperature and / or humidity. The humidification chamber can be configured to couple with the mount. A housing of the humidification chamber can be configured to be slidably received on the mount. For example, the mount can include a plurality of slots, and the housing of the humidification chamber can be slidably received in one of the slots.

[0171] The mount may include a heating element to heat the liquid in the humidification chamber. The humidification chamber may include a conductive plate to conduct heat from the heating element in the mount. In other embodiments, the humidification chamber includes a heating element to heat the liquid in the humidification chamber. The humidification chamber may be configured to be in electrical communication with the respiratory apparatus for operation of the humidification chamber.

[0172] In some embodiments, the humidification component includes a humidifier having a humidification chamber, the humidification chamber being connectable to a humidification base unit for operation of the humidification chamber. The humidification base unit can be configured to be connected to a mount. The housing of the humidification base unit can be configured to be slidably received on the mount. For example, the mount can include a plurality of slots, and the housing of the humidification base unit can be slidably received in one of the slots. The humidification base unit can include a heating element to heat a liquid in the humidification chamber.

[0173] A humidification chamber as disclosed herein may include an inlet port for receiving a flow of respiratory gas from a breathing apparatus and an outlet port for delivering a conditioned flow of respiratory gas to a patient. The outlet port may be connectable to an inhalation conduit to deliver the conditioned flow of respiratory gas to the patient via a patient interface.

[0174] In other embodiments, a humidification chamber as disclosed herein may include an inlet port for receiving a flow of respiratory gas from a breathing apparatus and a return port for returning the flow of conditioned respiratory gas to the breathing apparatus. The return port may be connectable to the breathing apparatus to return the flow of conditioned respiratory gas to the breathing apparatus.

[0175] In some embodiments, the humidification chamber includes a liquid inlet that connects to a liquid reservoir for refilling the humidification chamber. The humidification chamber can include a flow control mechanism that controls the flow of liquid into the humidification chamber. The humidification chamber can include at least one sensor that detects the level of liquid in the humidification chamber. The humidification chamber can include a float valve that controls the level of liquid in the humidification chamber.

[0176] In some embodiments, the humidification component is connectable to the mount via an adapter. The adapter can include a first inlet port for receiving a flow of respiratory gas from a breathing apparatus and a first outlet port for delivering the flow of respiratory gas to the humidification component. The adapter can further include a second inlet port for receiving a flow of conditioned respiratory gas from the humidification component. The adapter can also include a second outlet port for delivering the flow of conditioned respiratory gas from the humidification component to a patient or to a breathing apparatus.

[0177] The respiratory apparatus can be configured to operate in the following modes of operation: a first mode in which the respiratory apparatus delivers respiratory gas to the inhalation flow path and receives return of exhaled gas via the exhalation flow path, and a second mode in which the respiratory apparatus delivers respiratory gas to the inhalation flow path at a predetermined flow rate without return of exhaled gas from the patient.

[0178] In some embodiments, the respiratory apparatus is further configured to detect coupling of the humidification component to the mount to enable operation of the respiratory apparatus in the second mode. For example, the mount may include a sensor to detect coupling of the humidification component. In the second mode, the humidification component may be operable to condition the flow of respiratory gas in the inspiratory flow path to a predetermined temperature and / or humidity prior to delivery to the patient.

[0179] In some embodiments, the respiratory apparatus further includes a CO2 absorber configured to treat exhaled gas returned from the patient in the first mode before recirculating it to the patient. In the second mode, the CO2 absorber can be further configured to condition the respiratory gas in the inhalation flow path to a predetermined temperature and / or humidity before delivering it to the patient. The respiratory apparatus can be further configured to enable the CO2 absorber to condition the respiratory gas to a predetermined temperature and / or humidity in the second mode by one or both of modifying the amount of soda lime present in the CO2 absorber and modifying the amount of CO2 provided to the soda lime present in the CO2 absorber.

[0180] In a first mode, the respiratory apparatus may be operable to deliver respiratory gas to the patient by a first patient interface that forms a sealed interface with the patient's airway and returns exhaled gas to the respiratory apparatus via an exhalation flow path. In the first mode, the respiratory gas includes one or more anaesthetic agents. The first patient interface may be a mask or an endotracheal tube.

[0181] In a second mode, the respiratory apparatus may be operable to supply respiratory gas to the patient by a second patient interface that forms a non-sealing interface with the patient's airway. The second patient interface may be a nasal cannula.

[0182] In the second mode, the predetermined flow rate can be in the range of about 20 L / min to about 90 L / min.

[0183] In the second mode, the predetermined flow rate can be in the range of about 40 L / min to about 70 L / min.

[0184] In some embodiments, the respiratory apparatus can be configured to be in gas flow communication with a gas delivery apparatus that receives a supply of gas including NO, O2, and air. The gas delivery apparatus can include a gas mixing element that mixes one or more of NO, O2, and air in a ratio required to deliver respiratory gas in the first mode and / or the second mode, and a gas outlet that supplies gas from the gas delivery apparatus to the respiratory apparatus.

[0185] In some embodiments, the respiratory apparatus can be configured to be in gas flow communication with a flow meter that controls the flow of gas including one or both of air and O2 in the second mode.

[0186] In some embodiments, the respiratory apparatus can be configured in gas flow communication with one or more of: a pressure limiting valve configured to maintain a substantially stable pressure within the respiratory apparatus in the first mode; a variable volume section for displacement of gas in the first mode; a fresh gas flow to supplement the respiratory gas delivered to the patient in the first mode; and a vaporizer to vaporize one or more volatile anesthetic agents into the flow of respiratory gas before delivery to the patient in the first mode.

[0187] The invention will now be described in more detail with reference to the accompanying drawings, in which like features are designated with like numerals, and in which it should be understood that the illustrated embodiments are merely examples and should not be construed as limiting the scope of the invention as defined in the claims appended hereto. [Brief description of the drawings]

[0188] [Figure 1A] FIG. 1A is a schematic diagram showing components of a prior art anesthesia machine. [Figure 1B] FIG. 1B is a schematic diagram of a prior art ventilator 20. [Diagram 2]FIG. 1 is a schematic diagram of components of a prior art high flow system. [Diagram 3] FIG. 1 is a schematic diagram illustrating components of a system for delivering respiratory gas to a patient, according to one embodiment of the present disclosure. [Figure 4A-B] 1 is a schematic diagram of a gas delivery device for switching gas flows according to one embodiment of the present disclosure. [Figure 5A-B] FIG. 13 is a schematic diagram of a gas delivery device for switching gas flows according to another embodiment of the present disclosure having a common gas outlet. [Figure 6A-B] 13 is a schematic diagram illustrating a gas delivery apparatus and a second switching element for switching gas flow according to another embodiment of the present disclosure. FIG. [Figure 7A-B] FIG. 13 is a schematic diagram of a gas flow divider for switching gas flows according to another embodiment of the present disclosure. [Figure 8] FIG. 13 is a schematic diagram of a switching mechanism located between a gas source and first and second respiratory devices, according to another embodiment of the present disclosure. [Figure 9] FIG. 1 is a schematic diagram of a switching mechanism including a flow selector according to one embodiment of the present disclosure. [Figure 10] FIG. 13 is a schematic diagram of a switching mechanism including a flow selector according to another embodiment of the present disclosure. [Figure 11] FIG. 1 is a schematic diagram of a switching mechanism including a flow selector with a pressure controlled actuator. [Figure 12A-B] Figure 12A is a schematic diagram of a three-way actuator that provides ventilation bag connection in a manual first mode or bellows connection in a mechanical first mode, and Figure 12B is a schematic diagram of a three-way actuator with a pressure controlled actuator. [Figure 13A-B] FIG. 13 is a schematic diagram showing how a three-position switch can provide the physical fluid coupling necessary to provide mode switching. [Figure 14] FIG. 1 is a schematic diagram of a respiratory apparatus 1000 operable to deliver respiratory gas to a patient in three modes, including anesthesia ventilation mode, a high-flow mode, and a flushing mode. [Figure 15A]FIG. 1 is a schematic diagram of a system for delivering different modes of respiratory assistance, including ventilation, anesthesia, and high-flow respiratory assistance. [Figure 15B] FIG. 1 is a schematic diagram of a system for delivering different modes of respiratory assistance, including ventilation, anesthesia, and high-flow respiratory assistance. [Figure 16A-D] 15A and 15B. FIG. 15C is a schematic diagram illustrating various alternative embodiments of the system of FIG. [Figure 16E] 15A and 15B. FIG. 15C is a schematic diagram illustrating various alternative embodiments of the system of FIG. [Figure 17] FIG. 1 is a schematic diagram of a modular system for delivering different modes of respiratory assistance, including ventilation, anesthesia, and high-flow respiratory assistance. [Figure 18A-C] Figure 18A is a diagram of a gas flow switching mechanism according to one embodiment of the present disclosure, Figure 18B shows the switching mechanism in a top cross-sectional view in a first mode, and Figure 18C shows the switching mechanism in a top cross-sectional view in a second mode. [Figure 19A-B] 13A-13C show a gas flow switching mechanism according to another embodiment of the present disclosure in a first and second mode, respectively. [Figure 20] FIG. 1 is a schematic diagram of a system attached to a multi-lumen assembly for delivering breathing gas. [Figure 21] FIG. 2 is a schematic diagram showing a patient end of a multi-lumen assembly having a connector portion. [Figure 22A-C] 1A-1C are schematic diagrams illustrating retention mechanisms according to various embodiments of the present disclosure. [Figure 23A-B] FIG. 13 is a schematic diagram showing an actuator that switches the flow of breathing gas towards the patient end of the assembly. [Figure 24] FIG. 1 is a schematic diagram of a patient end connector used in a multi-lumen assembly to selectively control the flow of respiratory gas toward the patient end of the assembly. [Diagram 25] 1 illustrates a patient interface with CO2 sensing capability according to an embodiment of the present disclosure. [Figure 26] 1 illustrates a patient interface with CO2 sensing capability according to an embodiment of the present disclosure. [Figure 27]1 is a schematic diagram illustrating a piston-driven assembly for selectively directing exhaled gases from a patient mask and nasal cannula to a gas sampling line, the piston being in a first position. [Figure 28] 1 is a schematic diagram showing a piston-driven assembly for selectively directing exhaled gases from a patient mask and nasal cannula to a gas sampling line, the piston being in a second position. [Figure 29A-B] 29A and 29B are schematic diagrams illustrating the use of a pressure-controlled flow diverter to selectively direct exhaled gases from a patient mask (FIG. 29A) and a nasal cannula (FIG. 29B) to a gas sampling line. [Diagram 30] FIG. 1 is a schematic diagram of a three-way switch that selectively directs exhaled gases from a nasal cannula, an endotracheal tube, or an occlusive mask to a gas sampling line. [Diagram 31] 1 illustrates the use of multiple patient interfaces in the delivery of respiratory assistance according to an embodiment of the present disclosure. [Diagram 32] 1 illustrates the use of multiple patient interfaces in the delivery of respiratory assistance according to an embodiment of the present disclosure. [Diagram 33] 1 illustrates the use of multiple patient interfaces in the delivery of respiratory assistance according to an embodiment of the present disclosure. [Diagram 34] FIG. 13 is a schematic diagram of a connector that can be used to facilitate the exchange of components to deliver different modes of respiratory assistance according to an embodiment of the present disclosure. [Diagram 35] 13 is a schematic diagram of another connector used in accordance with an embodiment of the present disclosure. [Diagram 36] 13A-13C are schematic diagrams of alternative connectors for use with nasal cannulas used to deliver different modes of respiratory assistance according to embodiments of the present disclosure. [Fig. 37A-B] FIG. 37 is a schematic diagram of a connector which is a variation of the connector of FIG. 36. [Figure 38] FIG. 1 is a schematic diagram of a respiratory apparatus for delivering respiratory gas to a patient, which can be coupled to at least one vaporizer and humidification component, according to some embodiments of the present disclosure. [Figure 39]FIG. 39 is a front view of the respiratory apparatus of FIG. 38 illustrated as an anesthesia machine, including a vaporizer and humidification components coupled to a mount of the anesthesia machine, according to some embodiments of the present disclosure. [Diagram 40] FIG. 40 is a close-up view of the mount of the anesthesia machine shown in FIG. 39 with the humidification components removed and including a heating element in the mount, according to some embodiments of the present disclosure. [Diagram 41] FIG. 1 is a cross-sectional view of a humidification component for use with a respiratory apparatus that delivers respiratory gas to a patient, according to some embodiments of the present disclosure, the humidification component including a humidification chamber having a heating element electrically connected to a mount, the humidification chamber returning conditioned respiratory gas to the respiratory apparatus. [Diagram 42] FIG. 1 is a cross-sectional view of another humidification component for use with a respiratory apparatus delivering respiratory gas to a patient according to some embodiments of the present disclosure, the humidification component including a humidifier having a humidification chamber and a humidification base unit with a heating element electrically connected to a mounting base, the humidification chamber receiving respiratory gas from the respiratory apparatus and delivering conditioned respiratory gas to the patient via an inspiratory conduit. [Diagram 43] FIG. 13 is a cross-sectional view of another humidification component for use with a respiratory apparatus that delivers respiratory gas to a patient, according to some embodiments of the present disclosure, the humidification component including a humidification chamber having a conductive plate coupled with a heating element in a mount, the humidification chamber returning conditioned respiratory gas to the respiratory apparatus. [Diagram 44] FIG. 1 is a cross-sectional view of another humidification component for use with a respiratory apparatus that delivers respiratory gas to a patient, according to some embodiments of the present disclosure, the humidification component including a humidifier having a humidification chamber and a humidification base unit having a heating element, the humidification chamber returning conditioned respiratory gas to the respiratory apparatus. [Diagram 45] FIG. 1 is a schematic diagram of an adapter for connecting a humidification component to a respiratory apparatus that delivers respiratory gas to a patient, the adapter being connectable to a mount for the respiratory apparatus, according to some embodiments of the present disclosure. [Figure 46]FIG. 13 is a schematic diagram of a carburetor with an interlocking mechanism associated with a housing, the housing including two locking pins that are coupled to switches on a dial, according to some embodiments of the present disclosure. [Figure 47A-C] Schematic diagrams showing the vaporizer of FIG. 46 turned on with the locking pins extended (FIG. 47A), the vaporizer of FIG. 46 turned off with the locking pins retracted (FIG. 47B), and the vaporizer of FIG. 46 in a locked state with one locking pin fully retracted into the housing (FIG. 47C), in accordance with some embodiments of the present disclosure. [Figure 48] FIG. 47 is a schematic diagram showing the vaporizer of FIG. 46 positioned adjacent to a humidification component having the same interlocking mechanism associated with a switch on the housing and dial, according to some embodiments of the present disclosure. [Fig. 49A-B] 49A-49B are schematic diagrams showing the vaporizer and humidification components with the interlocking mechanism of FIG. 48 according to some embodiments of the present disclosure, where the vaporizer is switched on and the locking pin extends, thereby locking the humidification component in the off position (FIG. 49A), and the humidification component is switched on and the locking pin extends, thereby locking the vaporizer in the off position (FIG. 49B). [Figure 50] FIG. 13 is a schematic diagram illustrating another interlocking mechanism in which the vaporizer and humidification components include slots in the housing and a locking pin can slide between the slots to lock either the vaporizer or humidification component in an off position, according to some embodiments of the present disclosure. [Fig. 51A-B] 51A-51B are schematic diagrams showing the interlocking mechanism of FIG. 50 with the locking pin sliding to lock the humidification control in the off position (FIG. 51A), the humidification component switched on, and the vaporizer control locked in the off position (FIG. 51B) in accordance with some embodiments of the present disclosure. [Figure 52] FIG. 1 is a schematic diagram illustrating switching between vaporizer and humidification components in a respiratory device, according to some embodiments of the present disclosure. [Diagram 53] FIG. 1 is a schematic diagram illustrating a mechanical interlock switch for vaporizer and humidification components in a respiratory device, according to some embodiments of the present disclosure. [Figure 54] FIG. 13 is a schematic diagram illustrating a fixed flow meter for a second mode of operating the respiratory apparatus, which is a high-flow mode, according to some embodiments of the present disclosure. [Figure 55] FIG. 13 is a schematic diagram illustrating two variable flow meters for a second mode of operating the respiratory apparatus, which is a high-flow mode, according to some embodiments of the present disclosure. [Figure 56] FIG. 2 is a schematic diagram illustrating the flow of gas through a respiratory apparatus in a first mode, which is an anesthesia ventilation mode, according to some embodiments of the present disclosure. [Figure 57] FIG. 1 is a schematic diagram illustrating gas flow through the respiratory apparatus in a second mode, a high-flow mode, according to some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0189] Embodiments of the invention are discussed herein with reference to the drawings, which are not drawn to scale and are intended merely to aid in the explanation of the invention.

[0190] Components of anesthesia machines 1A is a schematic diagram showing components of an anesthesia machine 10 that can be configured to receive a gas supply 1060 that delivers respiratory assistance to a patient 300 via tubing connections known in the art. The gas supply 1060 can include one or more of anesthesia gases (e.g., nitric oxide (NO)), oxygen (O2) and supply air. The supply air can be ambient air. Flow meters can be incorporated into the gas supply 1060 or located upstream of the anesthesia machine 10 or incorporated into the anesthesia machine 10 to control the flow of gas through the anesthesia machine. Typically, such flow meters are manually controlled, but may also be precisely controlled by a controller in the anesthesia machine.

[0191] A breathing circuit delivers gas to the patient 300 and returns exhaled gas to the rebreathing component 140. Typically, the breathing circuit includes corrugated tubing, valves, and one or more patient interfaces that direct gas to the patient's airway and remove exhaled gas. In the schematic diagram of FIG. 1A, the breathing circuit is simplified and shown to include (but is not limited to) an inhalation conduit 110 and a first patient interface 120 that direct gas to the airway 310 of the patient 300, and an exhalation conduit 130 that collects exhaled gas. Thus, the first patient interface 120 may be a sealed interface, such as a sealed mask or endotracheal tube, and may be configured to direct exhaled gas from the patient 300 to an exhalation flow path 130 that returns the exhaled gas to the rebreathing component 140 of the anesthesia machine 10. The inhalation and expiratory conduits are typically connected to the patient interface by a Y-piece connector.

[0192] One or more vaporizers 150 convert volatile anesthetic agents, such as isoflurane and sevoflurane, from liquids to vapors and control the introduction of these agents into the breathing circuit at precisely controlled concentrations and doses as required by a user, typically an anesthesia clinician. Typically, the vaporizers 150 are manually controlled, but may also be precisely controlled by a controller in the breathing device. In some embodiments, the vaporizers 150 deliver the agents to the rebreathing component 140.

[0193] The anesthesia machine 10 is integrated with a ventilation system that ventilates the patient 300 during induction and after administration of anaesthetic agents to achieve continuous anesthesia. Typically, a manual ventilation bag 142 is used during induction (dashed line in rebreathing component 140) when volatile substances are delivered and before the patient is intubated. The compliance of the ventilation bag 142 allows the patient to inhale and exhale a certain amount of gas through a sealed first patient interface 120 in the form of a face mask. Once intubated, the ventilation mode changes from manual to mechanical, effectively isolating the manual ventilation bag 142 and the associated pressure relief valve 143 from the rebreathing component 140, and ventilation occurs via the mechanical system (dashed line in rebreathing component 140). Typically, this includes a collapsible bellows 145 that controls the tidal volume and timing of breaths delivered to the patient through the sealed first patient interface 120 in the form of an endotracheal tube. The gas provided to the patient can be controlled in pressure, flow rate or volume. Pressure relief valves 143, 146 provide relief of excess gas (resulting from the fresh gas flow from the vaporizer 150 and returned exhaled patient gas) from the rebreathing component 140 while preventing ambient air from entering the breathing circuit.

[0194] The rebreathing component 140 provides a gas recirculation system in which exhaled gas from the patient is treated as it flows through the circuit and then re-inhaled. This provides the advantage of recycling oxygen and volatiles present in the exhaled gas stream from the patient, reducing the presence of anesthetics in the atmosphere and reducing costs. The exhaled gas in the rebreathing component 140 is passed through a CO2 absorber 141, which may include a canister containing soda lime (or another CO2 absorbing material). The soda lime (a mixture of NaOH and Ca(OH)2) acts as a CO2 scrubber that removes CO2 before the gas in the rebreathing component 140 re-enters the inhalation conduit 110. Additionally, gas from the pressure relief valves 143, 146 is directed via exhaust (not shown) to an external scavenger system 144 that filters and collects anesthetic gases from the gas stream.

[0195] It should be understood that additional features may be provided as part of the anesthesia machine 10, such as patient monitoring, suction, pressure gauges, regulators, and "pop-off" valves to protect the patient and machine components from high pressure gases, as are known in the art, but for simplicity, these are not included in the illustrated example.

[0196] FIG. 1B is a schematic diagram of a ventilator 20 that can be used in an intensive care unit (ICU). The ventilator 20 ventilates a patient with gas from a gas supply 1060, often with active humidification by a humidifier 420 configured to heat and humidify the gas delivered to the patient's airway 310. The ventilator 20 can assist or replace the patient's own breathing by delivering breathing gas to the patient that is controlled to replicate the "normal" inhalation and exhalation breathing phases. The mechanical ventilator 184 can include a flow regulator and / or a blower to control the pressure, volume and respiratory rate of breathing gas delivered through an inhalation conduit 110 that is delivered to the patient by a sealed first patient interface 120. The sealed first patient interface can be invasive (e.g., an endotracheal tube or laryngeal mask airway (LMA)) or non-invasive (e.g., a sealed face mask). The exhaled gases leave the patient via the first patient interface and the exhalation conduit 130 where they are treated, for example by a filter 182, and released to the atmosphere. In some non-invasive ventilation systems, the exhaled gases exit a vent or exhaust port in the patient interface 120 or the exhalation conduit, which allows the exhaled gases to exit to the atmosphere without returning to the ventilator 20.

[0197] High Flow System Components FIG. 2 is a schematic diagram of components of a high-flow system 30 that can be configured to receive gas from a gas supply 1060 to deliver high-flow respiratory assistance to a patient 300. The gas supply 1060 can be one or more of anesthesia gas (e.g., nitric oxide (NO)), oxygen (O2) or supply air, preferably O2 and / or supply air. The supply air can be ambient air. The high-flow system 30 has a flow regulator 250 configured to generate a gas flow, which is passed through a humidifier 420 configured to heat and humidify the gas flow generated by the flow regulator 250. In some embodiments, the flow regulator 250 can comprise a gas supply 1060 as described below. The humidified high-flow gas flow is delivered to the patient 300 by the second inhalation conduit 210 and the non-sealing second patient interface 220. Typically, this is a nasal cannula, which directs the high-flow respiratory gas into the patient's airway 310 through one or both nostrils. An optional filter 230 can be provided between the inhalation conduit 210 and the second patient interface 220, allowing components of the breathing circuit upstream of the filter to be reused without risk of contamination by any exhaled gas inadvertently introduced by the second patient interface 220.

[0198] In some configurations, the flow regulator 250 is configured to deliver gas to the patient through the high flow system 30. In some embodiments, the flow regulator comprises a gas generating means, e.g., a blower, adapted to receive gas from an environment external to the high flow system 30 and propel the gas through the high flow system 30. In some configurations, the flow regulator 250 may comprise a source (e.g., oxygen or air) available from a hospital gas outlet or wall supply, or one or more containers of compressed air and / or another gas, and one or more valve arrangements adapted to control the rate at which gas exits the one or more containers. In some configurations, the flow regulator 250 may comprise an oxygen concentrator.

[0199] As used herein, "high flow" refers to any gas flow having a flow rate that is higher than usual / normal, such as higher than the normal inspiratory flow rate of a healthy patient, or higher than some other threshold flow rate relevant to the situation, without limitation. This may be provided by a non-sealed breathing system with substantial leakage, for example, occurring at the entrance to the patient's airway. This may also be provided with humidification to improve patient comfort, compliance and safety. "High flow" may refer to any gas flow rate that is higher than some other threshold flow rate relevant to the situation, for example, if a gas flow is provided to a patient at a rate that meets the inspiratory demand, that flow rate may be considered "high flow" because it is higher than the nominal flow rate that may have been provided otherwise. Thus, "high flow" is situational, and what constitutes "high flow" depends on many factors, such as the patient's health, the type of treatment / therapy / assistance being provided, the nature of the patient (large, small, adult, child), etc. One of ordinary skill in the art will understand what constitutes "high flow" in a particular situation. However, without limitation, some indications of high flow may be as follows:

[0200] In some configurations, high flow delivery of gas to the patient at a rate of about 5 or 10 liters per minute (5 or 10 LPM or L / min) or greater.

[0201] In some configurations, the high flow rate delivery of gas to the patient is at a flow rate of about 5 or about 10 LPM to about 150 LPM, or about 10 LPM to about 120 LPM, or about 15 LPM to about 95 LPM, or about 20 LPM to about 90 LPM, or about 20 LPM to about 70 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 thereof described herein, flow rates of gas delivered by embodiments of the disclosed systems can include, but are not limited to, flow rates of at least about 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150 LPM, or more, and useful ranges can be selected to be any of these values ​​(e.g., about 20 LPM to about 90 LPM, about 15 LPM to about 70 LPM, about 20 LPM to about 70 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). Thus, "high flow" or "high flow respiratory support" may refer to the delivery of gas to a patient at a flow rate of about 5 or about 10 LPM to about 100 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.

[0202] In "high flow", the gas delivered is selected depending on the intended use, for example, therapy or support. The gas delivered can include a percentage of oxygen. In some configurations, the percentage of oxygen in the gas delivered can 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%.

[0203] "High flow" flow rates for premature infants / infants / children (whose weight ranges from about 1 to about 30 kg) can vary. Flow rates can be set from about 0.4 LPM / kg to about 8 LPM / kg, with a minimum of about 0.5 LPM and a maximum of about 70 LPM. For patients under 2 kg, the maximum flow rate can be set at 8 LPM.

[0204] High flow can be used as a means of enhancing 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. High flow can be particularly useful before, during, or after a medical procedure. An additional benefit of high gas flow rates is that they increase pressure within the patient's airways, thereby providing patency support to open the airways, trachea, lungs / alveoli, and bronchi. The opening of these structures enhances oxygenation and, to some extent, aids in the removal of CO2.

[0205] Increased pressure can also prevent structures such as the larynx from obscuring the vocal cords during intubation. When humidified, high gas flow can also prevent the airway from drying out, mitigate mucosal damage, and reduce the risk of laryngospasm and the risks associated with a dry airway, such as nosebleeds, aspiration (as a result of nosebleeds), and airway obstruction, swelling, and bleeding.

[0206] As used herein, the terms subject and patient are used interchangeably. A subject or patient may refer to a human or animal subject or patient.

[0207] Reference herein to a range of numbers disclosed herein (e.g., 1-10) is intended to incorporate reference to all rational numbers within that range (e.g., 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9, and 10), and any range of rational numbers within that range (e.g., 2-8, 1.5-5.5, and 3.1-4.7), and thus all subranges of every range explicitly disclosed herein are hereby expressly disclosed. These are merely examples of what is specifically intended, and all possible combinations of numerical values ​​between the lowest and highest values ​​recited should be considered as being expressly stated in this application as well.

[0208] overview The embodiments of the present disclosure provide systems and apparatus that provide integration of different forms of respiratory assistance into a single system, or provide integrated switching between separate systems or apparatus that allow convenient use of those systems or apparatus by clinician users who may wish to switch between different forms of respiratory assistance delivered to a patient. Aspects of the present disclosure relate to various systems, devices, apparatus, switching mechanisms and lumen assemblies, as well as systems incorporating humidification. Those skilled in the art should appreciate that various features and advantages described in the context of one aspect are also useful in the context of another aspect, and that such combinations are within the scope of, and expressly form part of, the present disclosure.

[0209] Gas control system switching 3 is a schematic diagram illustrating components of a system 1000 for delivering respiratory gas to a patient 300. The system 1000 includes a first respiratory apparatus 100 configurable to deliver respiratory gas including one or more anesthetic agents to the patient, and a second respiratory apparatus 200 configurable to deliver respiratory gas to the patient at a predetermined flow rate. The first respiratory apparatus 100 may incorporate one or more components of anesthesia device 10 (FIG. 1A), and the second respiratory apparatus 200 may incorporate one or more components of high-flow system 30 (FIG. 2). For simplicity, like numerals are utilized to denote such components throughout this disclosure.

[0210] The switching means 700 is operable to select an operating mode of the system 1000, said operating mode being selected from a group including a first mode in which respiratory gas is delivered to the patient by the first respiratory apparatus 100 and a second mode in which respiratory gas is delivered to the patient by the second respiratory apparatus 200 at a predetermined flow rate, typically in the range of about 20 LPM to about 90 LPM for most patients.

[0211] 3 shows the switching means 700 with dashed lines to indicate the flexibility with which the switching means 700 can be deployed to provide switching between the first and second modes. In some embodiments, the switching means 700 can include one or more elements disposed between the gas supply 1060 and the first and second devices 100 and 200 and / or forming part of the first or second devices, as illustrated with reference to various embodiments described herein. Thus, it should be understood that the switching means 700, although shown diagrammatically as a box feature in FIG. 3, can be operative in that it consists of or includes one or more switching mechanisms configured to alter the flow of breathing gas within the system 1000 according to the selection of the first or second mode.

[0212] The switching mechanism may further comprise or include one or more switching elements. Thus, the switching means 700 allows a user to manually select an operating mode and may further include a user operable actuator that causes operation of the system components in the selected mode, and / or a sensor driven automation system that operates the system components in a mode determined, for example, by a sensor that detects which of the first and second patient interfaces 100 and 200 is coupled to the patient's airway 310. The various switching elements may be operatively coupled to operate substantially simultaneously, or in response to other switching elements or actuators, or under the control of a controller as will become apparent by reference to the non-limiting examples provided.

[0213] Although various embodiments are disclosed herein that prevent delivery of anesthetic agent to the patient when the second mode is selected, it should be understood that other approaches may be deployed as an alternative or in addition to the illustrated examples. For example, the system 1000 may stop the release of anesthetic agent to the patient by shutting down the vaporizer or reducing its function to a level that is ineffective. Alternatively or additionally, the system 1000 may stop the delivery of anesthetic agent to the first respiratory apparatus 100. Alternatively or additionally, the system may inactivate the anesthetic agent in the flow of respiratory gas delivered from the first respiratory apparatus 100 by using a neutralizer in the first respiratory apparatus that is activated when the system operates in the second mode, thus nullifying any anesthetic agent that may be flowing through the system. Although wasteful, this may be an important safety measure.

[0214] When the first mode is selected, the system 1000 directs breathing gases to a first inhalation flow path 110 where a first patient interface 120 directs the breathing gases into the airway 310 of the patient 300. The first patient interface 120 is a sealed interface, such as a sealed mask or endotracheal tube, that is configured to direct exhaled gases from the patient to an exhalation flow path 130 that returns the exhaled gases to the first respiratory apparatus 100. The returned exhaled gases are processed by a rebreathing component 140 as described with respect to FIG.

[0215] When the second mode is selected, the system 1000 isolates the flow of breathing gas from the first breathing apparatus 100 to prevent delivery of anesthetic gases, including NO and vaporized anesthetic agent, to the patient 300. Thus, when the second mode is selected, the system directs the flow of breathing gas to a second inhalation flow path 210, where a second patient interface 220 directs the breathing gas into the airway 310 of the patient 300, the second patient interface 220 being a non-sealing interface. Typically, the second patient interface is a nasal cannula having one or more nasal prongs that direct gas into one or both of the patient's nostrils.

[0216] In one embodiment, the switching means 700 includes a switching mechanism located between the gas supply 1060 and the first and second respiratory apparatus 100, 200 and includes a gas delivery device that receives a supply of gas including NO, O2 and / or air and provides a flow meter to control the flow of gas through one or more respiratory gas outlets. Preferably, the flow meter controls the flow of respiratory gas through one or more respiratory gas outlets in response to selection of the first or second mode of operation. This can be achieved in a number of ways.

[0217] In one example, shown diagrammatically in Figures 4A and 4B, the gas delivery device 1040 includes a gas mixing element 1042 that combines NO, O2, and air in the proportions required for operation of the system in a first mode. To control the proportions of gases entering the gas mixing element 1042, flow meters can be incorporated into the gas supply 1060 or located upstream of or incorporated into the gas delivery device 1040. Typically, such flow meters are manually controlled, for example, by proportional valves with rotary actuators, but may also be precisely controlled by the controller 1010 of the system 1000. Safety features may be incorporated to limit the flow rates and proportions of gases to within safe limits, for example to ensure that the ratio of O2 to NO does not fall below 0.25.

[0218] The flow meter 1090 controls the flow rate of respiratory gas from the gas mixing element 1042. The first gas outlet 1044A supplies respiratory gas from the gas delivery device 1040 to the first respiratory apparatus 100 when the first mode is selected (FIG. 4A), and the second gas outlet 1044B supplies respiratory gas from the gas delivery device to the second respiratory apparatus 200 when the second mode is selected (FIG. 4B). To achieve this, the first switching element 710 may be operatively coupled to the switching means 700, and the first switching element 710 may be operable to allow the inflow of NO into the gas mixing element 1042 when the first mode is selected (FIG. 4A) and to prevent the inflow of NO into the gas mixing element when the second mode is selected (FIG. 4B). At the same time, operation of the switching means 700 to select the first mode can cause the flow meter 1090 to be operatively coupled to the switching means 700, and the flow meter 1090 can limit the flow rate to a low flow rate of up to 15 LPM, preferably 10-15 LPM, and operation of the switching means 700 to select the second mode can cause the flow meter 1090 to increase the flow rate to a maximum of 90 LPM, preferably 40-70 LPM. A second switching element 720 operatively coupled to the switching means 700 is operable to control the flow of gas from the gas delivery device 1040 to one of the first gas outlet 1044A and the second gas outlet 1044B. When the first mode is selected, breathing gas (including NO) from the gas delivery device 1040 is directed only to the first gas outlet 1044A, as represented by the solid line in FIG. 4A. When the second mode is selected, breathing gas from the gas delivery device, excluding NO, is directed only to the second gas outlet 1044B, as represented by the solid line in FIG. 4B.

[0219] In another example, as shown diagrammatically in Figures 5A and 5B, the gas delivery device 1040 includes a single common gas outlet (CGO) 1044 for supplying breathing gas from the gas delivery device to the first breathing device 100 and the second breathing device 200 of the system 1000. A first switching element 710 operatively coupled to the switching means 700 is operable to control the input to the common gas outlet 1044 such that when a first mode is selected (Figure 5A), the common gas outlet receives breathing gas from a gas mixing element capable of mixing NO, air and O2, and when a second mode is selected (Figure 5B), the common gas outlet receives breathing gas from a flow meter 1090. A second switching element 720 coupled to the switching means 700 is operable to control the gas flow from the CGO 1044 to either the first breathing device 100 or the second breathing device. When the first mode is selected, breathing gas (including NO) from the gas delivery device 1040 is directed from the gas mixing element to the CGO 1044 and to the first breathing apparatus 100, as represented by the solid line in Figure 5A. When the second mode is selected, breathing gas including O2 (which may optionally exclude NO) is directed from the flow meter 1090 to the CGO 1044 and to the second breathing apparatus 200, as represented by the solid line in Figure 5B. It should be understood that in some embodiments, when the second mode is selected, breathing gas including air and O2 (which may optionally exclude NO) is directed from the flow meter 1090 to the CGO 1044 and to the second breathing apparatus.

[0220] 4A-5B, the first switching element 710 and the second switching element 720 can be operatively linked to operate substantially simultaneously with or subsequent to the operation of a switching means, e.g., a knob or actuator operable by a user or an electronic controller of the system. Alternatively, the switching means 700 can incorporate the first switching element 710 and the second switching element 720 such that they are incorporated into a common mechanical or pneumatic actuator operable by a user to trigger the first switching element 710 and the second switching element 720. The first and second switching elements can include, for example, one or more gas flow valves and / or diversion valves.

[0221] In the embodiment shown in Figures 4A-5B, the first respiratory apparatus 100 and the second respiratory apparatus 200 can be integrated into an integrated machine. This provides an advantageous complete respiratory support system 1000 that provides the ability to deliver anesthesia to a patient in a first mode, and is further supported in a second mode by high-flow respiratory support that may be beneficial, for example, when preparing a patient for intubation or weaning a patient off sedation. This arrangement conveniently places the functionality for user control of the second respiratory apparatus 200 that delivers high-flow respiratory support together with the functionality for user control of the first respiratory apparatus 100 that delivers sedation. The integrated machine also simplifies and reduces instrumentation that takes up valuable space in a clinical environment.

[0222] In some embodiments, the integrated machine may include a humidifier (not shown), typically located between the flow meter and the second patient interface 220 that delivers gas from the second respiratory device 200. The humidifier is configured to condition the respiratory gas to a predetermined temperature and / or humidity before delivery to the patient in the second mode. This has the advantage of streamlining the set-up of the humidifier by incorporating it into the daily routine of setting up the integrated system 1000.

[0223] However, it should be understood that the switching mechanism described may similarly be deployed in a system 1000 in which the first and second respiratory apparatus 100, 200 are separate machines. Beneficially, the switching means 700 as described provides coordinated control of the operation of these machines such that a single switching input simultaneously enables delivery of gas to the patient from the first respiratory apparatus 100 and blocks delivery of gas from the second respiratory apparatus 200 when a first mode is selected, or vice versa when a second mode is selected.

[0224] Advantageously, the embodiment shown in Figures 4A-5B eliminates the need to set up an additional oxygen supply, with both the first respiratory apparatus 100 and the second respiratory apparatus 200 receiving oxygen from a common supply 1060. Furthermore, this arrangement facilitates simultaneous switching to both the first respiratory apparatus 100 and the second respiratory apparatus 200 such that when the second mode is selected, the first respiratory apparatus 100 stops delivering gas to the patient 300. This improves safety by preventing anaesthetic agents, including NO and volatile anaesthetic agents vaporized by the first respiratory apparatus, from being delivered into the stream of gas delivered to the second patient interface 220. Furthermore, anaesthetic agents are prevented from entering the environment, avoiding inhalation of these agents by caregivers attending to the patient, and reducing waste.

[0225] In another example, shown diagrammatically in Figures 6A and 6B, a gas delivery device 1040 provides a first switching element 710 that controls the flow of respiratory gas (including anaesthetic) from the gas delivery device to the first respiratory apparatus 100, and a second switching element 720 external to the gas delivery device that controls the flow of respiratory gas through the second respiratory apparatus 200. As shown by dashed lines, the switching elements 710 and 720 are operatively linked to operate substantially simultaneously when a required mode of operation is selected by the switching means 700. In the first mode shown in Figure 6A, the first switching element 710 is open and the second switching element 720 is closed. This allows flow from the gas supply 1060 to the gas mixing element 1042 and to the outlet 1044 for gas to supply gas to the first respiratory apparatus 100, while flow through the second respiratory apparatus 200 is prevented. In a first mode of operation, breathing gas containing anaesthetic agent is delivered to the patient by a first patient interface 120 which also receives exhaled gas from the patient and returns it via an exhalation conduit 130 to a rebreathing component 140 of the first respiratory apparatus.

[0226] In a second mode of operation, illustrated in FIG. 6B, the first switching element 710 is closed and the second switching element 720 is open. This prevents the flow of gas to the gas outlet 1044, thereby preventing the delivery of respiratory gas, including the anaesthetic agent, from the first respiratory apparatus 100 to the patient. Meanwhile, the flow meter 1090 receives oxygen (optionally air) from the gas supply 1060 and increases the flow rate up to a pre-determined flow rate of up to 90 LPM, preferably 40-70 LPM. The high flow rate gas flow from the flow meter 1090 preferably passes through the humidifier 420 and is delivered to the patient 300 via the second patient interface 220. In this arrangement, the flow meter 1090, together with the preferred humidifier 420, form the main components of the second respiratory apparatus 200, as illustrated by the dashed lines surrounding these features. An advantage of having the second switching element 720 downstream of the flow meter 1090 is that no time is required for the flow meter to ramp up to a predetermined high flow rate when the second mode is selected. However, it should be understood that the second switching element 720 can be located upstream of the flow meter 1090 or downstream of the humidifier 420.

[0227] Change-over system with manifold In another example of the system 1000, where the switching mechanism 700 is located between the gas source 1060 and the first and second respiratory devices 100 and 200, a gas diverter receiving a supply of gas including anaesthetic gas and respiratory gas includes two switching means operable to control the flow of gas to the first and second respiratory devices. An example of a gas diverter 800 is illustrated in schematic form in Figures 7A and 7B. The gas diverter 800 receives a supply of gas including NO, O2 and / or air. The gas diverter 800 has a first switching element 710 that controls the flow of NO from the gas supply 1060 to an outlet 820 and a second switching element 720 that controls the flow of respiratory gas, i.e. O2, to an outlet 822 or 828. In some examples, the respiratory gas can include air, and the second switching element is comprised of paired elements 720A and 720B that cooperate to direct the flow of O2 and air to the outlets 822 / 828 and 824 / 826, respectively. As shown by the dashed lines within gas flow diverter 800, switching elements 710 and 720A,B are operatively linked to operate substantially simultaneously when a required mode of operation is selected by switching means 700. The first switching element 710 and second switching element 720 are operatively linked by either physical (e.g., pneumatic, magnetic, mechanical) means or electronic means such that operation of one switching element is substantially simultaneous with the other switching element.

[0228] In a first mode, illustrated in FIG. 7A, the first switching element 710 (which may be, for example, a flow control valve) opens to allow the flow of NO to the outlet 820, while the second switching elements 720A,B (which may be, for example, a gas diverter) direct the breathing gases (O2 and air) to the outlets 822 and 824, respectively. In a second mode, illustrated in FIG. 7B, the first switching element 710 closes to prevent the flow of NO to the outlet 820, while the second switching elements 720A,B direct the breathing gases (O2 and air) to the outlets 826 and 828, respectively. Thus, operation of the switching means 700 to select the first mode provides a supply of breathing gas and NO to the first breathing apparatus 100 (typically via a flow meter), while operation in the second mode prevents the supply of gas to the first breathing apparatus. Advantageously, the first switching element 710 blocks the supply of NO outside the gas flow diverter 800 when the gas flow diverter is in the second configuration, such that the breathing gas delivered to the second respiratory apparatus 200 excludes the anesthetic agent.

[0229] Advantageously, the gas diverter manifold 800 is installed between a gas supply 1060, such as a gas wall supply in an operating room (or other medical location), and a gas inlet port of the first respiratory apparatus 100, which is in fluid communication with the vaporizer 150 (see FIG. 1). The gas diverter manifold 800 is also installed between the gas supply 1060 and a gas inlet port of the second respiratory apparatus. Activation of the second mode automatically stops the supply of NO to the first respiratory apparatus 100 and the diversion of oxygen and air to the second respiratory apparatus 200. Advantageously, the gas diverter 800 can be supplied as a stand-alone component that can be retrofitted to existing anesthesia machines, or can be incorporated into newly built machines. In some embodiments, during the cessation of the supply of NO to the first respiratory apparatus 100, a small residual flow of O2 (and optionally air) may flow from the gas diverter manifold 800 to the first respiratory apparatus. This may be desirable in scenarios where an existing anesthesia machine that has been retrofitted with gas flow diverter 800 is configured to sound an alarm if the machine detects that it is not receiving flow and / or pressure from the O2 or air supply.

[0230] Standalone gas diverter Although the gas diverter 800 has been described in the context of a component of the system 1000, it should be understood that the gas diverter 800 may be supplied as a stand-alone device for use with a breathing system, such as a system providing the functions of a first breathing apparatus 100 (typically an anesthesia machine) and a second breathing apparatus 200 (delivering high-flow respiratory assistance). Although the gas diverter 800 illustrated in Figures 7A and 7B provides three inlets and three outlets to the first breathing apparatus 100 and two outlets to the second breathing apparatus 200, it should be understood that the air inlet and outlet may be omitted such that the gas diverter 800 receives only NO and O2 flows. The gas diverter 800 includes a manifold between the inlets and outlets, which provides the necessary flow paths to deliver gas to the first breathing apparatus 100 and the second breathing apparatus 200 in the first and second modes, respectively. In some embodiments, the manifold may combine the NO and O2 flows so that they are delivered to the first breathing apparatus 100 via a single common gas outlet. Thus, in one embodiment, gas flow splitter 800 includes a first outlet (combining 820 / 822), a second outlet 828, and a manifold between the first and second inlets and the first and second outlets that provides a first flow path to the first outlet and a second flow path to the second outlet. In this embodiment, gas delivery device 800 is operable in a first configuration in which the first flow path is open and the second flow path is closed, and a second configuration in which the second flow path is open and the first flow path is closed. In the first configuration (FIG. 7A), gas delivery device 800 blocks the flow of anesthetic gas to the outlet.

[0231] As disclosed in connection with Figures 7A and 7B, the gas delivery device 800 includes one or more switching elements that create first and second flow paths within the manifold. The one or more switching elements can include a first valve 710 that controls the flow of anesthesia gas (NO) within the manifold such that in a first configuration, the first valve 710 is open and directs NO to the first flow path, and in a second configuration (Figure 7B) the first valve 710 is closed. The switching element can include a second valve 720 that controls the flow of breathing gas (O2) within the manifold such that in a first configuration, the second valve 720 directs breathing gas to the first flow path, and in a second configuration, the second valve 720 directs breathing gas to the second flow path. Ideally, one or both of the first and second valves are operable to control the flow rate of gas therethrough. When a third gas, such as room air or pressurized air from the flow regulator 250, is delivered through the gas delivery device 800, the manifold can mix the breathing gases (air and O2) such that the second valve 720 (shown as 720A, B) directs the breathing gas to a single outlet 828 for delivery of the breathing gas to a second breathing apparatus in the second configuration. Ideally, the second valve is operable to control the O2 concentration in the breathing gas delivered to the first and second flow paths. This can be done directly by controlling the proportion of O2 gas flowing through the manifold, or indirectly by controlling the flow rate of O2.

[0232] In some embodiments, the gas delivery device 800 can be operated in a third configuration in which both the first and second flow paths are open and a plug or other shutoff mechanism can be utilized at the patient end to prevent flow through the first or second patient interface. A gas mixer (not shown) can also be included that mixes the received gases in the ratio required to deliver the required therapy. The gas delivery device 800 can include a switching means operable by a user to select a configuration for operation of the gas delivery device, which is achieved by switching elements (e.g., valves and gas flow diverters) in the manifold. The switching means can be located, for example, in the gas diverter device 800, the first respiratory apparatus 100, or the second respiratory apparatus 200, or in the patient interface where the respiratory gas is directed to the patient's airway.

[0233] The switching means may be pneumatic, mechanical, electronic, or utilize any other mechanism suitable for triggering the operation of a switching element. In embodiments utilizing electronic switching means, the gas delivery device 800 is configured to be connected to a power source, which may include a battery. Ideally, both mains and battery power sources are utilized such that in the event of a power outage, the battery is charged to ensure continued operation of the gas delivery device until the procedure is completed or until mains power is restored.

[0234] In some embodiments, the switching means is activated in response to detection of a change in condition detected by one or more system sensors, which may include, for example, one or more of pressure sensors, CO2 sensors, O2 sensors, flow sensors, gas concentration sensors, etc., ideally positioned and configured to determine whether a breathing circuit delivering gas to a patient airway is associated with a first patient interface in which gas (e.g., including an anaesthetic agent) is delivered to the patient airway by a substantially sealed interface, or a second patient interface in which gas, excluding the anaesthetic agent, is delivered to the patient by a non-sealed interface. The switching means may be in wired or wireless communication with one or more switching elements to control operation of the gas delivery device according to a user-selected configuration.

[0235] In some embodiments, the gas delivery device includes an output module (similar to monitor 1094 of FIG. 20) that provides one or both of a visual and audible indication of the configuration in which the gas delivery device is operating. The output module may also present other parameters to the user related to the use of the gas delivery device or the overall breathing system, such as flow rate and gas concentration. Operation of the output module may be initiated, for example, when a switching means is operated by the user to select the second configuration, or may have a button or actuator that switches on and off such that a visual and / or audible indication is provided at all relevant times while switched on.

[0236] O2 Switching In another example of the system 1000, where the switching mechanism 700 is located between the gas source 1060 and the first and second respiratory apparatuses 100, 200, the switching mechanism includes a first switching element 710 operable to direct the flow of O2 to the first respiratory apparatus 100 in a first mode and to the second respiratory apparatus 200 in a second mode. FIG. 8 provides a schematic diagram illustrating the operation of such a switching mechanism 700 in a first mode. Notably, in the first mode, the second switching element 720 is also open and, in a preferred embodiment, is operable to allow the first respiratory apparatus 100 to perform in either manual (147) or automatic (148) ventilation / rebreathing modes. In the embodiment shown in FIG. 8, the manual first mode has been selected. The second switching element 720 is responsive to the first switching element 710. Thus, when the first switching element 710 is switched to the second mode, O2 is directed to the second respiratory apparatus 200 (represented by the flow regulator 250 and humidifier 420) and the second switching element moves to a lowermost position 722 blocking flow from the rebreathing component 140 of the first apparatus to the patient 300. In some embodiments, when the first switching element 710 is switched to the second mode, O2 and / or air can be directed to the second respiratory apparatus 200. Operation of the first switching element 710 in the second mode blocks the flow of O2 to the gas mixing element 1042 of the first respiratory apparatus 100, and therefore also to the patient 300 through the first patient interface.

[0237] As in the embodiment illustrated in Figures 4A-5B, the arrangement of Figure 8 eliminates the need to set up an additional oxygen supply, i.e., both the first respiratory apparatus 100 and the second respiratory apparatus 200 receive oxygen from a common supply 1060. Furthermore, this arrangement facilitates simultaneous switching to both the first respiratory apparatus 100 and the second respiratory apparatus 200 such that the first respiratory apparatus 100 stops delivering gas to the patient 300 when the second mode is selected. This improves safety by preventing anesthetic agents, including NO and volatile agents vaporized by the vaporizer 150 of the first respiratory apparatus, from being delivered into the stream of gas delivered to the second patient interface 220. Furthermore, it reduces waste by preventing anesthetic agents from entering the environment, avoiding inhalation of these agents by caregivers attending to the patient.

[0238] The embodiment shown in Figures 6A-8 is particularly useful in a system 1000 in which the first respiratory apparatus 100 and the second respiratory apparatus 200 are separate machines. Ideally, in each case, the second respiratory apparatus 200 includes a humidifier 420 (particularly shown in Figure 8) that conditions the respiratory gas to a predetermined temperature and / or humidity before delivery to the patient in the second mode. Furthermore, while as previously described the first switching element 710 and the second switching element 720 are operatively linked to operate substantially simultaneously with or subsequent to the operation of the switching means 700, it should be understood that in some embodiments the switching means may incorporate the first and second switching elements such that they are integrated with a common mechanical or pneumatic actuator that is user operable to trigger the first and second switching elements. The first switching element 710 and the second switching element 720 may include one or more gas flow valves or flow diverter valves.

[0239] Switching Interface / Control In some embodiments, such as those relating to the examples previously described, it may be desirable for the predetermined flow rate of respiratory gas delivered to the patient 300 in the second mode to be selectable by a user operating the switching means from a range of about 20 LPM to about 90 LPM, although in some cases, such as for pediatric or neonatal patients, a lower range may be desired. Preferably, the required predetermined flow rate is user selectable from a plurality of available predetermined flow rates, e.g., 0 LPM, 40 LPM, and 70 LPM, although it should be understood that additional and / or different predetermined flow rates may be selectable within the high flow ranges disclosed herein.

[0240] Selection of the required pre-determined flow rate can be achieved in some embodiments by manipulation of a switching means 700, which includes a flow rate selector, e.g., in the form of a knob, slide switch, touch screen, or other actuator, that provides user selection of the required pre-determined flow rate from a plurality of pre-determined flow rates. An example of a flow rate switching element 730 associated with a flow rate selector is presented in the schematic diagram of FIG. 9, which is similar to FIG. 8, except that the flow rate regulator 250 is replaced by two flow rate regulators 250A, 250B, e.g., operating at 70 LPM and 40 LPM, respectively, which are in fluid communication with the flow rate switching element 730, which also has an "off" position 732. In some embodiments, the flow rate switching element 730 can replace the first switching element 710, although in some embodiments it may be desirable to provide the flow rate switching element 730 in addition to the first switching element 710 to avoid issues with delays in increasing the gas flow rate when the second mode is selected. Preferably, the flow switching element 730 is operatively coupled to the second switching element 720 such that operation of the flow selector to deliver flow from the second respiratory device 200 (i.e., to the second patient interface via the humidifier 420 as shown) in the second mode prevents delivery of respiratory gas to the patient from the first respiratory device.

[0241] In some embodiments, operation of the flow switching element 730 to select a flow rate of 0 LPM allows for the supply of O2 to the first respiratory device. This is shown diagrammatically in FIG. 10, where the flow switching element 730 controls the flow of O2 to the first respiratory device 100 and the second respiratory device 200. Thus, when the flow switching element 730 is operated to select one of two predefined flow rates (illustrated as 40 LPM and 70 LPM), there is a flow of O2 to the second respiratory device, i.e., the second mode, and when the flow switching element 730 is operated to select 0 LPM, flow from the O2 supply is directed to the first respiratory device 100, i.e., the first mode. The flow switching element 730 and the second switching element 720 are operatively coupled such that operation of the flow selector in the second mode activates switching of the second switching element to a bottom position 722 that closes off flow from the rebreathing component 140 of the first device to the patient 300. Operation of the flow switching element 730 in the second mode prevents the flow of O2 to the gas mixing element 1042 of the first respiratory apparatus 100, so that there is no flow to the first patient interface in the second mode.

[0242] In another example including a flow rate selector, a pressure controlled actuator is arranged to control the flow rate to the first and second respiratory apparatus 100, 200, as shown in the schematic diagram of FIG. 11. In this arrangement, a pressure controlled actuator 740 detects backflow pressure from the second respiratory apparatus 200. During operation in the second mode, i.e., when the flow rate switching element 730 is operated to select an available non-zero flow rate, the pressure controlled actuator blocks the flow of gas to the first respiratory apparatus 100. When the flow rate switching element 730 is operated to select a flow rate of 0 LPM, back pressure from the second respiratory apparatus 200 increases, triggering the pressure controlled actuator 740 to direct the flow of gas to the first respiratory apparatus 100.

[0243] 3-position bag / vent / HF switch In some embodiments, the switching means 700 provides further functionality to the system 1000 in that it can provide a user selection of operation of the system in a second mode along with a first manual or first mechanical mode of operation of the first respiratory device. In the first manual mode of operation, the first respiratory device 100 deploys a ventilation bag for manual ventilation of the patient 300, e.g. during intubation, where the medical professional manually squeezes the bag to control the timing and tidal volume of the respiratory gas delivered by the first patient interface to the patient's airway. In the first mechanical mode of operation, the first respiratory device 100 deploys a bellows to provide mechanical ventilation of the patient 300, e.g. once sedated, the bellows controls the tidal volume and the timing of inspiration / expiration. In both cases, a pressure relief valve is provided to avoid overpressure in the system of breathing circuits connected to the patient's airway.

[0244] In one embodiment, the additional functionality of providing selection of the first manual, first mechanical, or second operating modes of the system 1000 is achieved by including a three-way actuator. One example is provided in the schematic diagram of FIG. 12A, which shows a three-way actuator 750 providing fluid coupling of the rebreathing component 140 of the first respiratory device 100 to the ventilation bag 142 in the first manual mode, or to the bellows 145 in the first mechanical mode, and to the second respiratory device 200 in the second mode. Ideally, the first and second respiratory devices receive O2 from a common supply, as described above. To prevent the anaesthetic supplemental fresh gas flow (FGF) from the vaporizer 150 from contaminating the respiratory gas supplied to the second respiratory device, a pressure-controlled actuator 740 can be positioned to detect a drop in backpressure that triggers the actuator to shut off the FGF when the system 1000 is operating in the second mode. This is shown diagrammatically in Figure 12B and ensures the delivery of O2 to the patient's airways via the second respiratory apparatus 200 and second patient interface 220 in the absence of anaesthetic agents. Advantageously, the use of a pressure controlled actuator as in Figures 11 and 12B provides an elegant solution to the problem of FGF contamination of the gas delivered in the second mode, while avoiding the need to physically or functionally couple the operation of separate switching elements located in different components of the system 1000.

[0245] Figures 13A and 13B are schematic diagrams showing how a three-position switch (Figure 13A) can provide the necessary physical fluid coupling to provide switching between a manual first mode of operation (POS I), a mechanical first mode of operation (POS II), and a second mode of operation (POS III). Figure 13B shows a schematic of the breathing circuit including the patient interface connected in each mode.

[0246] 13A and 13B provides a physical three-position switch, it should be understood that an electronic three-position switch may be utilized to provide similar control. The electronic three-position switch may communicate with the controller 1010 to control operation of the first respiratory apparatus 100 in a manual first mode or a manual second mode, or switch to a second operational mode in which respiratory gas is delivered by the second respiratory apparatus 200. This type of electronic switch may enjoy wired or wireless communication, the latter providing flexibility in the location of the electronic actuator, which may include one or more of a button panel or touch screen mounted to a housing that is removably positionable, and ideally mountable, in multiple locations such as the patient's bed, the anesthesiologist's body, or the hardware delivering gas to the patient.

[0247] An electronically enabled switch can be physically attached to one or both of the first patient interface 120 or the second patient interface 220 to allow for rapid switching of the system's operating modes when the patient interface is changed, for example, when moving from pre-intubation to intubation, or when weaning the patient from sedation. Thus, a button or electronic switch located on the patient interface can be activated to cause the system 1000 to select an operating mode that safely delivers gas to the patient via that interface. Alternatively, a foot pedal or foot operated switch or voice control may be utilized. Each of these have the potential to improve the accessibility of mode selection while the anesthesiologist is away from the controls located on the anesthesia machine.

[0248] Switches NHF on and off depending on changes detected by the machine While some embodiments of the system provide mechanical, pneumatic, or other physical control and operational coupling of the switching elements, in some embodiments, the system 1000 includes a controller 1010 that receives input from one or more sensors deployed throughout the system. The sensors detect whether a breathing circuit coupled to a patient's airway is associated with a first patient interface 120 for use with a first respiratory apparatus 100 or a second patient interface 220 for use with a second respiratory apparatus 200. This information is used by the controller 1010 to operate the switching means 700 to select an operating mode. Thus, when the sensors detect that a breathing circuit is associated with the first patient interface 120, the controller 1010 ensures that the system is operating in a first operating mode. Conversely, when the sensors detect that a breathing circuit is associated with the second patient interface 220, the controller 1010 ensures that the system is operating in a second operating mode that delivers nasal high flow (NHF) respiratory assistance.

[0249] The sensor may include a pressure sensor arranged to measure back pressure in one or both of the first and second respiratory apparatuses 100 and 200. The system 1000 may provide a continuous or intermittent flow of respiratory gas through the first and / or second respiratory apparatuses 100 and / or 200 to enable measurement of back pressure within the first and / or second respiratory apparatus. In some embodiments, this continuous or intermittent flow of respiratory gas has a lower flow rate, pressure and / or volume than the flow of respiratory gas provided to the patient in the first and / or second modes. A different flow resistance value is associated with each of the first (sealing) and second (non-sealing) patient interfaces 120 and 200 when coupled to the patient 300, used in the first and second modes, respectively. When the measured backpressure indicates that the respiratory gas is delivered to the patient by a sealed patient interface that is substantially sealed with the patient, the controller 1010 determines that the breathing circuit is associated with a first patient interface and operates the system 1000 in a first mode in which respiratory gas and anesthetic agent can be delivered to the patient 300 and exhaled gas is returned to the rebreathing component. Alternatively, when the measured backpressure indicates that the respiratory gas is delivered to the patient by a non-sealed patient interface, the controller 1010 determines that the breathing circuit is associated with a second breathing device and operates the system 1000 in a second mode in which respiratory gas that excludes anesthetic agent is delivered to the patient at a predetermined (high flow) flow rate. In some embodiments, the pressure sensor may be located at or downstream of the flow regulator 250 of the system, but may be located at any convenient location in the gas flow path between the patient airway and the flow regulator 250.

[0250] Alternatively / additionally, the one or more sensors may include a CO2 sensor associated with a first breathing circuit associated with the first patient interface 120 and / or a second breathing circuit associated with the second patient interface 220. In such an embodiment, the controller 1010 determines the breathing circuit in which the exhaled gas from the patient contains a higher concentration of CO2 than ambient air to be the breathing circuit to be coupled to the patient's airway. If the CO2 concentration in both breathing circuits is higher than ambient air, the controller determines the breathing circuit with the higher CO2 concentration to be the breathing circuit to be coupled to the patient's airway.

[0251] Alternatively / in addition, the sensors may include one or more proximity sensors, such as acoustic (including audible and / or ultrasonic), optical (including infrared), radio frequency, pressure (in the inspiratory / expiratory conduits and / or mask cuff), flow, electrical conductivity, resistance, temperature or other sensors, to determine which of the breathing circuits is coupled to the patient's airway by the first or second patient interface. Such proximity sensors are described in further detail in WO2016157105, the contents of which are incorporated herein by reference.

[0252] The switching means 700 may include one or more actuators operable by a user, such as, but not limited to, one or more of a button, a switch, a knob, a foot-operated switch or a pedal. Alternatively / additionally, the switching means 700 may include one or more of an electronic input device, a touch screen, a voice-activated sensor, etc., which may be operable in cooperation with an electronic controller of the system as described below. The actuator or actuators of the switching means may be located at or near the first patient interface 120 or the second patient interface 220, where breathing gas is delivered to the patient by the first or second breathing apparatus 100. Locating one or more of the actuators at or near the patient end of the breathing circuit that delivers gas to the patient's airway provides convenience to clinicians working on the patient through the stages of anesthesia, where it is often necessary to switch between the operating modes of the system and the form of respiratory support delivered. Locating the actuators that allow mode selection at the patient end may be more convenient and time-saving for the clinician and others in the vicinity. In other arrangements, the system 1000 can be configured to detect whether the first or second patient interface is attached to the patient and change the mode of operation accordingly.

[0253] It should be understood that the switching means 700 can include one or more switching mechanisms, such as mechanical, electronic, electromechanical, electromagnetic, pneumatic, or any other suitable switching mechanism for achieving the functions disclosed herein. Furthermore, the one or more switching mechanisms can be coupled to the switching means via wired and / or wireless coupling, using techniques readily understood and ascertainable by those skilled in the art. The switching mechanism can include an actuator operable by a user of the system 1000 to select the required mode of operation, and can include or consist of any of the switching mechanisms described. In some embodiments, the actuator includes an electronic input device that wirelessly communicates with the controller 1010 of the system 1000 and is movably positionable in different positions relative to the patient 300 and / or the first and second respiratory apparatuses 100 and 200.

[0254] In some embodiments, the one or more switching mechanisms are operable to control one or more characteristics of the respiratory gas delivered to the subject, such as, but not limited to, the presence of volatile substances, flow rate, gas composition, gas concentration, temperature and / or humidity.

[0255] For the sake of brevity, some features of the first respiratory apparatus 100 are not necessarily shown in the figures. However, it should be understood that in a preferred embodiment, the first respiratory apparatus 100 performs the functions of the anesthesia machine 10 and includes one or more of a CO2 absorber 141 configured to process the returned exhaled gas in the first mode before recirculating it to the patient, a pressure limiting valve 146 configured to maintain a substantially stable pressure in the system in the first mode, a variable volume 145 for displacement of gas in the first mode (e.g., using a bellows or a ventilation bag), a fresh gas flow to supplement the anesthesia gas delivered to the patient in the first mode, and a vaporizer 150 to vaporize a volatile anaesthetic agent into the breathing gas delivered to the patient in the first mode.

[0256] Similarly, for the sake of brevity, some features of the second respiratory apparatus 200 are not necessarily shown in the figures. However, it should be understood that in a preferred embodiment, the second respiratory apparatus 200 includes one or more of a flow source 250 or regulator configured to deliver high-flow respiratory assistance as described herein and generate a gas flow through the system. A humidifier 420 configured to condition the respiratory gas in the second mode to a predetermined temperature and / or humidity prior to delivery to the patient is also typically provided, but may be omitted in some cases.

[0257] Anesthesia machine with 3 modes including O2 flushing FIG. 14 is a schematic diagram of a respiratory device 1000 operable to deliver respiratory gas to a patient by an inhalation gas flow path and in several modes to receive exhalation gas via an exhalation gas flow path. The respiratory device can operate in a number of modes. In a first mode, the respiratory device typically utilizes components of a first respiratory device 100 as described herein to deliver respiratory gas containing one or more anesthetic agents to the inhalation gas flow path and receive exhalation gas return via an exhalation gas flow path. In a second mode, the respiratory device typically utilizes components of a second respiratory device 200 as described herein to disable the flow of one or more anesthetic agents and deliver respiratory gas containing O2 at a predetermined flow rate to the inhalation gas flow path without exhalation gas return. In a transient mode, the respiratory device disables the flow of one or more anesthetic agents and delivers high concentration O2 to the inhalation gas flow path.

[0258] The respiratory apparatus includes a switching means operable to select one of the operating modes from a plurality of modes. The switching means may include one or more actuators, such as a button, switch, knob, foot-operated switch or pedal, shown in FIG. 14 as switching elements 710, 720, operatively coupled to deliver respiratory gas in a first mode or a second mode in a manner similar to that described in connection with FIG. 4A and FIG. 4B. In the first mode, the respiratory apparatus is operable to deliver respiratory gas, including anaesthetic, to the patient by a first patient interface that forms a sealing interface with the patient's airway and returns the exhaled gas to the respiratory apparatus by an exhaled gas flow path as described herein. Preferably, the respiratory apparatus includes a first respiratory apparatus 100 having the features of FIG. 1A corresponding to an anesthesia machine, the first patient interface being a sealing mask or an endotracheal tube.

[0259] In the second mode, the respiratory device is operable to deliver respiratory gas to the patient through a second patient interface, such as a nasal cannula, that forms a non-sealing interface with the patient's airway. In particular, in the first mode, FGF containing anesthetic agents from the NO source and / or vaporizer 150 enters the inhalation gas flow path to supplement the patient's sedation. However, in the second and transient modes, the flow of FGF to the second patient interface is disabled by the switching element 720 to prevent the release of anesthetic agents into the environment through the non-sealing interface, reducing waste while avoiding inhalation of these agents by caregivers attending the patient. In some configurations, the inhalation flow paths in the second and transient modes are the same. In some configurations, the inhalation flow paths in the first and third modes are the same.

[0260] In a preferred embodiment, the transient mode is activated only during operation of the actuator, which is normally biased off. For example, the switching means may include a button or trigger configured to be activated by a user to operate the respiratory apparatus in the transient mode while the trigger or button is pressed, and release of the button or trigger disables the transient mode. Operating the button or trigger may open the flush valve 730, which allows a high flow of O2 to bypass the gas mixing element 1042 and the flow meter 1090 and flow through the system. The transient mode may be used to flush the respiratory apparatus with O2, for example during set-up or after use. Ideally, a user may select the transient mode to flush the respiratory apparatus, including the first and / or second respiratory apparatus. This includes flushing the first respiratory apparatus 100 in a manual operating mode, where the bag ventilation components are flushed, or in a mechanical operating mode, where the mechanical bellows system components are flushed. This always involves manual (bag) or mechanical (bellows) ventilation modes, which are typically selectable by the user by operating a switch that alters the gas flow path to the selected ventilation component, although some machines may require manual connection of a ventilation bag.

[0261] For operation of the respiratory device in the second mode, it is desirable to configure the device in gas flow communication with a flow regulator configured to provide a gas flow through the system at a predetermined flow rate consistent with high-flow respiratory assistance, and a humidifier configured to condition the respiratory gas to a predetermined temperature and / or humidity before delivery to the patient in the second mode. These features are represented in FIG. 14 by a second respiratory device 200 having the features of FIG. 2 together with an optional filter 230. However, it should be understood that humidification can be provided to a limited extent by reconfiguring the CO2 absorber in the first respiratory device, if it is also configurable for high-flow assistance. In this regard, it should be noted that although FIG. 14 shows two gas outlets 1044A, 1044B, a common gas outlet can supply gas to an integrated device that can be configured to provide respiratory assistance in the first and second modes, and also to provide a transient mode in which the system is flushed with O2. This arrangement allows a common gas source to be used to operate the breathing apparatus in all three modes, eliminating the need to set up an additional oxygen supply to deliver high-flow respiratory support and enable O2 flushing.

[0262] Blower-driven anesthesia machine with high-flow mode Another aspect of the disclosure provides a system for delivering respiratory gases to a patient that allows for the delivery of different modes of respiratory assistance including ventilation, anesthesia, and in some embodiments high-flow respiratory assistance. Figures 15A and 15B are schematic diagrams of a system 1300 having a flow generator 1350 adapted to receive fresh air and gases 1310 from the environment and force it through the system for delivery to the airway 310 of a patient 300 through an inspiratory conduit 110 connected to a sealed first patient interface 120. A switching actuator, such as a button, switch, knob, foot-operated switch or pedal, or an electronic interface in operative communication with the system controller, can be operated by a user to select an operating mode of the system 1300 in which, in a first mode (FIG. 15A), breathing gas is delivered in a closed gas flow circuit in which exhaled gas is returned to the system by the exhalation conduit 130 for rebreathing by the patient, and in a second mode (FIG. 15B), breathing gas is delivered in an open gas flow circuit without rebreathing.

[0263] Ideally, the flow generator 1350 is a blower with variable control selectable by a user or a system controller. Ideally, the switching actuator includes or is operatively connected to a switching mechanism 1370 that controls the flow of fresh gas to the system 1300 according to an operating mode selected using the switching actuator. In a first mode (FIG. 15A), the switching mechanism 1370 blocks the first fresh respiratory gas flow to the system and allows the return of exhaled gas to the system, while in a second mode, the switching mechanism allows the first fresh respiratory gas flow to the system and blocks the return of exhaled gas to the system. In some embodiments, the switching mechanism 1370 is a gas flow diverter, which in some arrangements may be a pressure-controlled gas flow diverter configured to detect back pressure within the system 1300 and, upon detection of high back pressure, operate in a first mode and indicate that a sealed patient interface returning exhaled gas to the system has been applied to the patient 300.

[0264] Typically, the switching mechanism 1370 is located upstream of the flow generator 1350, as shown in Figures 15A and 15B. The switching mechanism 1370 is operatively coupled to the flow generator 1350 such that manipulating the switching actuator to select a first mode causes operation of the flow generator at a low flow rate, such as less than 15 LPM, selecting a second mode causes operation of the flow generator at a higher flow rate compatible with patient ventilation, and selecting a third mode causes operation of the flow generator at a high flow rate, up to 90 LPM.

[0265] In some embodiments, operation of the system 1300 in the first mode allows for the delivery of anesthesia. In such embodiments, the system 1300 also receives a supply of oxygen from the O2 source 1060 and a vaporized volatile anesthetic agent, such as sevoflurane, from the vaporizer 150. These gases are mixed in the required ratio and concentration (as determined by a user or by the system's controller) by the gas mixer 1042. The mixed gas is delivered to the patient via the inhalation conduit 110 and the sealed first patient interface 120 into the patient's airway 310. Exhaled gases are returned by the first patient interface 120 to the exhalation conduit 130 and the system 1300 where CO2 is removed by the CO2 absorber 141 and the gas is recirculated back to the inhalation pathway.

[0266] In some embodiments, operation of the system 1300 in the second mode allows for the provision of ventilatory assistance to the patient. This form of assistance can be delivered by the same first patient interface 120 as in the first mode of operation, with the difference that the switching mechanism 1370 operates to allow the flow of fresh air into the system 1300 while preventing gas recirculation. Thus, gases returned by the expiratory conduit 130 are exhausted to the environment or exhaust, or released through a vent in the patient interface through which the respiratory assistance is delivered. In another form of respiratory assistance delivered in the second mode, the first patient interface 120 is replaced with a non-sealing patient interface, such as a nasal cannula, and the flow rate generated by the flow generator is increased to deliver a high flow rate, whereby the system 1300 operates in a second mode delivering high-flow respiratory assistance to the patient 300. Thus, operating the switching actuator to select the second mode causes operation of the flow generator at a flow rate sufficient to deliver high-flow respiratory assistance (e.g., up to 90 LPM). In embodiments where the switching actuator 1370 is a pressure-controlled gas flow diverter, low back pressure within the system 1300, coincident with connection of a second non-sealing patient interface 220, such as a nasal cannula (or disconnection of the expiratory conduit 130 from the system 1300), automatically allows fresh gas flow to the system while shutting off gas recirculation. During operation of the system in the second mode, O2 may also be provided from the O2 source 1060, with the O2 concentration being selected by operation of a switching actuator, which may be operatively coupled to the O2 source or gas mixer 1042, or by manual selection of the O2 concentration in a supply controller provided with the O2 source. The system 1300 is also configured to prevent the supply of anesthetic gas to the system when the second mode is selected. This may be accomplished by the user manually shutting off the vaporizer 150, or by providing a vaporizer switching mechanism operatively coupled to the switching mechanism 1370 and / or the system controller 1010.

[0267] In some embodiments, the system 1300 includes a pressure relief valve 146 that maintains a substantially stable gas pressure within the system when operating in the first mode, which would otherwise rise as oxygen and volatiles are added to the system 1300 in the first mode. An exhalation valve 143 or variable flow restriction can be provided to regulate the gas flow within the system 1300 to generate the exhalation and inhalation breathing cycles, particularly if this cannot be achieved by regulating the flow rate through the flow generator 1350. As shown in Figures 15A and 15B, in some embodiments, the system 1300 is configured to receive a supply of anesthetic gas from a vaporizer 150 located downstream of the flow generator 1350 before the inhalation conduit 110 and the exhalation conduit 130 are connectable with the system 1300 downstream of the flow generator. However, this is not required.

[0268] 16A-16E are schematic diagrams illustrating various alternative embodiments of the system 1300. In FIG. 16A, the vaporizer 150 is located downstream of the flow generator 1350, and the switching mechanism 1370 provides a separate gas flow path through a separate inhalation conduit to deliver high-flow respiratory assistance to the second non-sealing patient interface. An adjustable pressure limiting valve (APL) is provided to release return gas into the scavenger system (as described in connection with FIG. 1). However, it should be understood that in various disclosed embodiments, the APL can be represented by any form of relief valve, and the adjustable pressure limiting valve is merely one example. In FIG. 16B, the vaporizer 150 is provided in the return gas flow path upstream of the CO2 absorber 141 (although it can also be located downstream of the CO2 absorber 141). In FIG. 16C, the vaporizer 150 is connected in parallel with the flow generator 1350, and a ventilation bag 142 provides manual ventilation of the patient. In Fig. 16D, the vaporizer 150 is connected upstream of a flow generator 1350 that receives and forces anaesthetic-containing gas into the inhalation conduit 1100. In Fig. 16E, the system 1300 includes a gas flow reflector 1360 configured to collect exhaled anesthetic gas from the patient and return it to the inhalation gas flow path during the subsequent inspiration phase.

[0269] In various embodiments, the system 1300 includes a humidifier configured to condition the respiratory gas to a predetermined temperature and / or humidity before delivery to the patient in the second mode. Ideally, the humidifier (not shown) is located downstream of the blower and before the second patient interface 220.

[0270] The schematic diagram of Fig. 17 shows another system for delivering respiratory gas to a patient that allows delivery of different modes of respiratory assistance, including ventilation, anesthesia, and in some embodiments, high-flow respiratory assistance. Here, the system 1300 is operable in a first mode and a second mode, the first mode including a recirculating gas flow between the system and the patient's airway, and the second mode including a non-recirculating gas flow between the system and the patient's airway. The system 1300 includes a first module 1380 including a first set of respiratory components and a second module 1390 including a second set of respiratory components. The second module 1390 is configured to cooperate with the first module 1380 (or vice versa) to switch between the two modes. Thus, the system 1300 can operate in a first mode when the first module 1380 is powered up or coupled with the second module 1390, and the system can operate in a second mode when the first module is powered down or decoupled from the second module such that the second module functions independently of the first module.

[0271] In some embodiments, during the first operating mode of the system 1300, the gas delivered to the patient 300 in the recirculated gas flow includes an anesthetic delivered by the vaporizer 150, which vaporizes the volatile anesthetic into the respiratory gas delivered to the patient. Thus, the first set of respiratory components of the first module 1380 may include one or more of a CO2 absorber 141 configured to process the returned exhaled gas in the first mode before recirculating it to the patient, a pressure limiting valve 146 configured to maintain a substantially stable pressure in the system in the first mode, and a variable volume (such as a ventilation bag 142 or a bellows) for displacement of gas in the first mode. The fresh gas flow from the vaporizer 150 supplements the anesthetic gas delivered to the patient in the first mode.

[0272] During the second mode of operation, the second module 1390 operates independently from the first module 1380 to deliver, for example, ventilatory assistance and in some embodiments high-flow respiratory assistance to the patient 300. Thus, the second set of respiratory components of the second module 1390 may include one or more of a flow source, such as a blower 1350, configured to generate a gas flow through the second set of respiratory components, an inhalation conduit 110, and a patient interface configured to direct gas from the non-recirculated gas flow to the patient's airway. When the system 1300 is used in the second mode to deliver ventilatory assistance, the patient interface may be a sealed patient interface, and exhaled gases are returned to the system via the exhalation conduit 130 where they are exhausted to the atmosphere or exhaust (not recirculated to the patient). Alternatively, the exhaled gases may exit the sealed patient interface through a port hole in the interface or the exhalation conduit. When the system 1300 is used in the second mode to deliver high-flow respiratory assistance, the patient interface is ideally a non-sealed second patient interface, such as a nasal cannula. A humidifier (not shown) may be provided to condition the respiratory gas to a predetermined temperature and / or humidity before delivery to the patient in the second mode, and a filter may be provided upstream of the patient interface to reduce contamination of the second set of respiratory components upstream of the filter so that they can be reused.

[0273] In some embodiments, the first module 1380 includes a first gas outlet 1388 and a first gas inlet 1386, and the second module 1390 includes a second gas inlet 1396 and a second gas outlet 1398, where the first gas outlet is connectable to the second gas inlet and the first gas inlet is connectable to the second gas outlet for operation of the system 1300 in a first mode, as shown in FIG. 17. Thus, in a first mode of operation, the system utilizes the same patient breathing circuit comprising the inhalation conduit 110 and the exhalation conduit 130 to deliver breathing gas, including anaesthetic, to the patient. A one-way valve 149 may be provided to prevent backflow of gas to the patient. It should be appreciated that in use, the user may switch the patient interface to ensure that gas delivered in the first mode is via a sealed first patient interface, such as a sealed mask or endotracheal tube, and gas delivered in the second mode is via a non-sealed second patient interface, such as a nasal cannula, or a sealed patient interface where exhaled gas is vented or discarded, i.e., not returned to the patient.

[0274] In particular, operation of the system 1300 in the first mode allows a first fresh breathing gas flow 1310 into the system while the connection between the second gas outlet 1398 and the first gas inlet 1386 allows the return of exhaled gas into the system. A one-way valve 149A can be provided to prevent backflow of return gas into the fresh gas supply 1310. Meanwhile, operation of the system 1300 in the second mode allows a first fresh breathing gas flow 1310 into the system independent of the first module 1380 while the decoupling between the second gas outlet 1398 and the first gas inlet 1386 prevents the return of exhaled gas into the system. Furthermore, operation in the second mode prevents the release of anesthetic agent from the system, for example by providing a shutoff valve at the first gas outlet 1388 and / or by switching off the vaporizer 150 and / or by providing a bypass around the vaporizer 150.

[0275] Switching provided to breathing circuit Another aspect of the disclosure relates to switching the delivery of respiratory gas to a patient 300 in a first or second mode at the patient end of a breathing circuit. In one embodiment, a system for delivering respiratory gas to a patient includes a flow regulator 250 configured to generate a gas flow through the system in a gas delivery circuit and a switching mechanism forming part of the gas delivery circuit. Figure 18A is a perspective schematic diagram of a switching mechanism 900 configured to switch a gas flow path in the gas delivery circuit according to a selection of a first operating mode in which the inhalation gas flow path 910 is in fluid communication with the first patient interface 120 or a second operating mode in which the inhalation gas flow path 910 is in fluid communication with the second patient interface 220.

[0276] Typically, the first patient interface 120 forms a substantially sealed interface with the patient's airway and receives exhaled gas from the patient. Thus, in the first mode, the exhaled gas path 930 returns the exhaled gas to the system, in particular to the ventilator or anesthesia machine of the system, where the exhaled gas is treated, for example by filtration, and either vented to the atmosphere or recirculated in the anesthesia machine rebreathing system. Typically, the second patient interface 220 forms a non-sealing interface with the patient's airway and is, for example, a nasal cannula, allowing the venting of the exhaled gas to the environment around the non-sealing nasal prongs of the cannula.

[0277] In one embodiment shown in FIG. 18A, the switching mechanism 900 includes an "X-piece" connector 950 and an actuator 940 in the form of a rotary switch that is user operable to switch the gas flow path in the gas delivery circuit. The actuator may take any suitable form, such as a knob, switch, lever, etc. Also shown in FIG. 18A is an optional anesthesia reflector 960. FIG. 18A is a top cross-sectional view of the switching mechanism 900 of FIG. 18A in a first mode, where breathing gas in the inhalation flow path 910 is directed to the first patient interface 120, and exhalation gas is returned to the switching mechanism through a common conduit and returned to the system through the exhalation gas flow path 930. FIG. 18C is a top cross-sectional view of the switching mechanism 900 of FIG. 18A in a second mode, where breathing gas in the inhalation flow path 910 is directed to the second non-sealing patient interface 220. No gas is returned in this mode.

[0278] In some embodiments, the system is configured to receive a user input to select a first mode of operation in which the flow source 1350 generates a low flow rate below a predetermined flow rate, or a second mode of operation in which the flow source generates a high flow rate equal to or greater than a predetermined flow rate, and the switching mechanism 900 operates in response to the flow rate of gas in the inhalation gas flow path generated by the flow source. In such an embodiment, a bi-stable switch 948 as illustrated in Figures 19A and 19B may be used. If the flow through the "X-piece" exceeds a threshold flow rate, e.g., 15 LPM, or a threshold flow rate corresponding to the delivery of high-flow respiratory assistance, for example, the flow is delivered to the second patient interface 220 (Figure 19B). Below the threshold flow rate, the flow is delivered to the first patient interface 110, and the exhalation gas is returned through the exhalation flow path 930 (Figure 19A). However, it should be understood that the switching mechanism may include any suitable mechanism, including, but not limited to, one or more of a gas flow diverter, a pneumatic switch, a rotary switch, a lever, a flap, or a valve, or the like.

[0279] In some embodiments, a user-controlled actuator 1440 operates a flow diverter that controls the flow of respiratory gas to the patient. An example is shown diagrammatically in Figures 23A and 23B. In some embodiments, the actuator 1440 is operatively coupled to the system 1000 such that user manipulation of the actuator to switch flow delivery between patient interfaces switches control of the system 1000 to a mode of operation in which respiratory gas is delivered. For example, in Figure 23A, the actuator 1440 is in a first position and directs respiratory gas from the first inhalation conduit 1410 to the first patient interface 120, which returns exhaled gas via the exhalation conduit 1430. This is consistent with a first mode of operation that provides delivery of respiratory gas including an anesthetic agent and return of exhaled gas for processing by the rebreathing components as disclosed herein. In Figure 23B, the actuator is in a second position and directs respiratory gas from the inhalation conduit 1410 to the second patient interface 220, which is a non-sealing interface such as a nasal cannula. This requires the system controller 1010 to direct breathing gas into the inhalation conduit 1410 consistent with the second mode of operation (i.e., high flow without anesthetic). Exhaled gas is expelled into the environment. This is consistent with the second mode of operation providing delivery of high flow respiratory assistance as disclosed herein.

[0280] In some embodiments, a system utilizing the switching mechanism 900 includes one or more sensors configured to monitor one or more characteristics of the gas in the gas delivery circuit and controls operation of the flow regulator 250 based on the one or more monitored characteristics. These characteristics may indicate one or more of flow, pressure, and CO2, for example. The system uses various techniques described herein to control operation of the flow regulator 250 to generate a low flow rate (e.g., less than 15 LPM) when the one or more sensors indicate that the respiratory gas flow is to the first patient interface 110, and to generate a high flow rate when the one or more sensors indicate that the respiratory gas flow is to the second patient interface 220.

[0281] As will be appreciated by those skilled in the art upon consideration of this disclosure as a whole, a system utilizing the switching mechanism 900 or other switching concepts disclosed herein may include one or more components commonly found in anesthesia machines, such as a CO2 absorber configured to process returned exhaled gas in a first mode before recirculation to the patient, a pressure limiting valve configured to maintain a substantially stable pressure within the system in a first mode, a variable volume (e.g., ventilation bag or bellows) for gas replacement in the first mode, a fresh gas flow to supplement the anesthetic gas delivered to the patient in the first mode, and a vaporizer to vaporize volatile anesthetic gas into the respiratory gas delivered to the patient in the first mode. Additionally, such a system may include one or more features of a high-flow respiratory support system, such as a flow regulator configured to provide a high flow rate through the system, and a humidifier configured to condition the respiratory gas to a predetermined temperature and / or humidity before delivery to the patient in a second mode.

[0282] Although the switching mechanism 900 has been described in the context of being a component of the system 1000, it should be understood that the switching mechanism 900 may be provided as a separate component of such a system. In this sense, the switching mechanism 900 may be considered a respiratory gas connector having an inlet port 911 connectable to a gas flow conduit 910 for receiving respiratory gas from a respiratory assistance system, a first port 921 connectable to a first gas flow path for delivering respiratory gas to a patient via the first patient interface 120, a second outlet port 922 connectable to a second gas flow path for delivering respiratory gas to a patient via the second patient interface 220, and a switching mechanism 940 operable to switch the connector between a first operating mode in which the connector directs gas from the inlet port to the first outlet port and a second operating mode in which the connector directs gas from the inlet port to the second outlet port.

[0283] The expiratory gas port 931 is connectable to an expiratory gas conduit, and in a first mode, the switching mechanism directs expiratory gas in the first gas flow path to the expiratory gas conduit. The switching mechanism may be operatively connectable to a controller 1010 of the respiratory assistance system, and operation of the connector switching mechanism 940 may select a first mode of operation of a second mode of operation. The first mode of operation causes the controller to operate the respiratory assistance system in a first mode in which respiratory gas including an anesthetic agent is delivered to the gas flow conduit 910 connected to the connector. The second mode of operation causes the controller to operate the respiratory assistance system in a second mode in which respiratory gas is delivered at a predetermined flow rate to the gas flow conduit 910 connected to the connector. In some embodiments, the connector switching mechanism 940 may be operatively connectable to the controller of the respiratory assistance system, such that operation of the connector switching mechanism to select the second mode of operation causes the controller to block the flow of an anesthetic agent in the respiratory gas.

[0284] A sensor may be provided to detect one or more characteristics of the gas at the first outlet port 921 or the second outlet port 922, said characteristics being used to determine whether the connector is connected to the patient's airway by the first (sealing) patient interface 120 or the second (non-sealing) patient interface 220, and the sensor provides an input to a controller of the respiratory assistance system that automatically selects a corresponding operating mode of the respiratory assistance system. The one or more characteristics include, but are not limited to, gas pressure, CO2 concentration, and gas flow rate. A sensor line may be positioned inside a conduit that provides a gas flow path between the sensor and the respiratory assistance system controller.

[0285] In another aspect, the first patient interface 120 and the second patient interface 220 can be used simultaneously to provide a switching mechanism. Thus, when the first and second patient interfaces are applied to the patient simultaneously, the first mode is selected, and when only the second patient interface is applied to the patient, the second delivery mode is selected. In one arrangement, the first patient interface is a mask that can be sealed over the second patient interface, which is a nasal cannula, without obstructing flow through the cannula. Inhalation flow is delivered through the cannula and exhalation gases are returned through the face mask. This arrangement can be deployed to deliver anesthesia in a closed system, utilizing the cannula to deliver anesthesia to the patient and the mask to return exhalation gases. A pressure sensor can be used to determine when the mask is applied to the patient and sealed over the cannula, such that when a target pressure is detected at the mask (e.g., inside the mask or in the mask cuff), the system responds by initiating delivery of anesthesia through the nasal cannula. Commonly owned patent publication WO2015145390 discloses a mask suitable for such situations and is hereby incorporated by reference.

[0286] 31-33 show one example of how switching between modes of use of a system for delivering respiratory gas to a patient can be provided by using a first and a second patient interface simultaneously or separately. The system includes a flow source configured to provide a flow of gas through the system in a gas delivery circuit having an inhalation gas flow path 210 and an exhalation gas flow path 130. In a first mode, the system is operable to deliver respiratory gas to the patient via the inhalation gas flow path 210 and the first patient interface in fluid communication with the inhalation flow path, and to deliver exhalation gas from the patient via the exhalation gas flow path 130 and the second patient interface in fluid communication with the exhalation gas flow path, the respiratory gas comprising a first flow parameter. In a second mode, the system is operable to deliver respiratory gas to the patient via the inhalation gas flow path 210 and the third patient interface, the respiratory gas comprising a second flow parameter. The first and second flow parameters include or correspond to a first flow rate and a second flow rate, respectively. In some embodiments, the first flow rate is less than 15 L / min and the second flow rate is greater than 15 L / min. In some embodiments, the second flow rate is in the range of about 20 L / min to about 90 L / min, optionally in the range of about 40 L / min to about 70 L / min. However, it should be understood that the first flow parameters may alternatively or additionally include pressure and / or volume parameters.

[0287] As shown in FIG. 31, the first patient interface is a non-sealing patient interface shown as a nasal cannula 224 in fluid communication with the inhalation gas flow path 210, and the second patient interface is a sealing patient interface shown as a mask 124. In FIG. 32, the nasal cannula 224 and the mask 124 are simultaneously applied to the patient and the system is operable in a first mode to provide anesthesia ventilation, with the mask 124 configured to seal over the nasal cannula 224 and with the patient. In this arrangement, breathing gas is delivered to the patient via the inhalation conduit providing the inhalation gas flow path 210 and the nasal cannula 224, and exhalation gas from the patient is delivered from the patient via the mask 124 and the exhalation conduit providing the exhalation gas flow path 130. In FIG. 31, only the nasal cannula 224 is applied to the patient to deliver breathing gas to the patient's airway in a second mode to provide high-flow respiratory assistance. In FIG. 31, the first and third patient interfaces are the same, the nasal cannula 224. In some embodiments, the exhalation flow path 130 is not needed or is inoperative in the second mode. In alternative embodiments, breathing gas is delivered to the patient via the gas flow path 130 and mask 124, and exhaled gas from the patient is delivered from the patient via the nasal cannula and gas flow path 210. In such embodiments, the gas flow path 130 is the inhalation gas flow path and the gas flow path 210 is the exhalation gas flow path. In some embodiments, the exhaled gas is returned to the system.

[0288] FIG. 33 shows an arrangement for operation of the system in a third mode. In the third mode, anesthesia ventilation is delivered by an endotracheal tube 126. Here, an inhalation conduit providing an inhalation gas flow path 210 is disconnected from a nasal cannula 224 and coupled to an inlet of a coupling 600. Similarly, an exhalation conduit providing an exhalation gas flow path 130 is disconnected from a mask 124 and coupled to an outlet of a coupling 600. The patient end of the coupling 600 is connected to a fourth patient interface shown as an endotracheal tube 126. In some embodiments, the endotracheal tube 126 may be a laryngeal mask or a tracheotomy interface. In the third mode, a respiratory gas including a third flow parameter, which may include one or more of a flow rate, a pressure, or a volume parameter, may be delivered to the patient.

[0289] An advantage of mode switching according to the examples described in connection with Figures 31-33 is that a single inspiratory conduit and a single expiratory conduit may be used to provide multiple modes of respiratory assistance to a patient, thereby reducing the cost and complexity of the breathing circuit utilized to treat the patient.

[0290] FIG. 34 is a schematic diagram of a novel connector 1700 that can be used to facilitate the exchange of components for delivering respiratory assistance in the first and second modes as described in connection with the embodiment of FIGS. 31-33. The connector 1700 is configured to mate with a standard Y-piece connector 1750. In normal use, the Y-piece connector 1750 is configured to mate at port 1755 with a conduit that provides a flow of respiratory gas to a mask 124 of the type shown in FIGS. 31 and 32. The Y-piece connector 1750 receives a flow of respiratory gas from the inhalation flow path 210 and provides an exit path for exhaled gas from the patient via the exhalation gas flow path 130. When used consistently with FIG. 32, the mask 124 forms a sealed interface with the patient's airway to deliver respiratory gas, which may include an anesthetic agent, while returning exhaled gas to the breathing apparatus via the exhalation gas flow path 130.

[0291] To facilitate interoperability between different patient interfaces, a novel connector 1700 can be used that provides a wall 1720 configured to protrude into a Y-piece connector 1750. When connected, the wall 1720 separates the inspiratory flow path 210 and the expiratory flow path 130 flows into separate limbs 1710 and 1730. In use, the connector 1700 is configured to couple the first limb 1710 with a conduit attached to the nasal cannula 224 and the second limb 1730 with a conduit attached to the face mask 124. Due to the separating wall 1720, the inspiratory flow to the cannula 224 (see Figs. 31, 32) remains separated from the expiratory flow received from the mask 124 (when used in the configuration of Fig. 32). To quickly switch to the device required to deliver assistance in the third mode, the connector 1700 can be detached from the Y-piece connector 1750, which is instead coupled to the endotracheal tube 126. Advantageously, connector 1700 can be used to connect and disconnect Y-piece connector 1750 to nasal cannula 224 and mask 124 simultaneously with fewer disconnections / reconnections of parts and less room for error for quick connection of endotracheal tube 126. When switching back to the first support mode with mask 124 configured to seal over nasal cannula 224 (as in FIG. 32 ), endotracheal tube 126 is disconnected from Y-piece connector 1750 and connector 1700 is reconnected to simultaneously reconnect cannula 224 and mask 124.

[0292] FIG. 35 is a schematic diagram of an alternative connector 1800 provided for use in the arrangement shown in FIG. 32 in place of the standard Y-piece connector 1750. Using the connector 1800, the mask 124 is used to remove exhaled gases via the exhaled gas flow path 130. In a second mode of operation (FIG. 32), the connector 1800 can remain in place connected between the mask and the exhaled gas flow path 130 and disconnected from the inhaled gas flow path 210, which is instead coupled to the nasal cannula 224. The one-way valve 1810 operates to prevent exhaled gases from the mask from venting to the atmosphere, as flow in the inhaled gas flow path 210 is biased towards the mask 124 and no inhaled gas conduit is attached to the connector 1800 in this mode of operation. To operate in a third mode (FIG. 33), the inhaled conduit can be reconnected to the connector and the mask 124 can be disconnected and replaced with a connection of the endotracheal tube 126. The advantage of this arrangement is that the connector 1800 can be used to deliver both modes of respiratory support shown in Figures 32 and 33, while avoiding the need to disconnect and reconnect all of the conduits required to deliver and remove gas, as is the case with a standard Y-piece connector.

[0293] 36 is a schematic diagram of another novel connector 1900 configured for use in an embodiment in which the nasal cannula 224 is used to deliver different modes of respiratory assistance. The connector 1900 is connectable to three conduits providing fluid communication with each of a first inhalation gas flow path 210A configured to provide a gas flow for delivery of nasal high-flow respiratory assistance, a second inhalation gas flow path 210B configured to provide a gas flow for delivery of anesthesia ventilation, and an exhalation gas flow path for exhalation gases from the patient. A switch 1910 (changeover valve, solenoid, etc.) is provided to change the internal flow paths of the connector 1900 when a different mode of assistance is selected. When the nasal cannula 224 is used to deliver anesthesia ventilation, the switch 1910 is in the position shown in solid lines, allowing delivery of respiratory gas (including anesthetic) from the inhalation gas flow path 210B and providing a path for exhalation gas 130. During rebreathing, a bag mask can be applied over the nasal cannula 124 and sufficient pressure can be applied (e.g., by an attendant) to enable the cannula to provide both inspiratory and expiratory flow paths. For high-flow respiratory assistance, the switch 1910 is in the position shown in dashed lines. The switch 1910 can be operatively linked with other switching means in the system operated by the user (or a system controller) to determine the mode of assistance to be delivered.

[0294] 37A and 37B are schematic diagrams of connectors 1950A,B, a variation of the connector 1900 of FIG. 36, with connections for both a nasal cannula 224 and a mask 124. This connector 1950A,B provides for the delivery of a high nasal flow when the switch 1910 is in the dashed position. When the switch 1910 is in the solid position, the device can be positioned as shown in FIG. 32 to provide anesthesia ventilation by the cannula 224, with exhaled gases being removed by application of a face mask 124. FIG. 37A shows the connector 1950A with all flow paths within a unitary connector member. FIG. 37B shows the connector 1950B with an inhalation flow path with connections for the nasal cannula 124, with a separate conduit used to provide the exhalation gas flow path 130 attached to the mask 124.

[0295] Typically, a system 1000 in which the patient interface shown in Figures 31-33 is used may include a controller 1010 in communication with the flow regulator 250, and one or more of a sensor or input interface in communication with the controller to provide input to the controller for controlling the flow regulator to provide a flow of respiratory gas in the first or second mode. The sensor and / or input interface may also be configured to provide input to the controller for controlling the flow regulator to provide a flow of respiratory gas in a third mode.

[0296] The system may also include a humidifier 420, whereby the breathing gas is heated and / or humidified in the second mode before being delivered to the patient. In some embodiments, the breathing gas in the first and / or third modes may be heated and / or humidified by the humidifier 420. Ideally, the exhaled gas from the patient is returned to the inhalation gas flow path 210 in the first and third modes. A CO2 absorber 141 may be provided to remove CO2 from the exhaled gas before returning it to the inhalation gas flow path 210.

[0297] 3 Lumen Tube Assembly Another aspect of the disclosure provides a multi-lumen assembly 1400 for use with a respiratory assistance system 1000 as illustrated diagrammatically in FIG. 20. The multi-lumen assembly 1400 includes a plurality of conduits as illustrated in FIG. 21. A first inhalation conduit 1410 has a first conduit inlet end connectable to a first gas outlet 1044 of the respiratory assistance system and configured to deliver respiratory gas including an anesthetic agent to a patient. The first inhalation conduit 1410 has a first conduit outlet end connectable to a first patient interface 120 configured to sealingly engage and direct flow to the patient's airway. In the illustrated embodiment, the first patient interface 120 is illustrated diagrammatically as a sealing mask, although it should be understood that the first patient interface may be an endotracheal tube, an LMA, or the like.

[0298] A second inhalation conduit 1420 has a second conduit inlet end connectable to a second gas outlet 1048 of the respiratory assistance system and configured to deliver high flow respiratory gas to the patient at a flow rate of 20 L / min to 90 L / min. The second inhalation conduit 1420 has a second conduit outlet end connectable to a second patient interface 220, which is configured to direct flow to the patient's airway and may be a non-sealing interface such as a nasal cannula, for example via a three-way safety connector.

[0299] An expiratory conduit 1430 has an expiratory conduit outlet end connectable to the expiratory gas inlet 1046 of the respiratory assistance system. The expiratory conduit 1430 is configured to return expiratory gases from the patient to the respiratory assistance system.

[0300] In some embodiments, the multi-lumen assembly 1400 includes or is operable with a connector portion 1415, where the outflow end of the first inhalation conduit 1410 and the inflow end of the exhalation conduit 1430 form a common gas flow path 1416. A schematic diagram is provided in FIG. 21. The common gas flow path 1416 is defined by a single gas exchange conduit 1417 connectable to the first patient interface 120. Ideally, the connector portion 1415 includes a taper, such as a 22 mm taper, to reduce the overall cross section of the assembly in the region of the single gas exchange conduit 1417. In some embodiments, the connector portion is configured to direct the second conduit outflow end of the second inhalation conduit 1420 to branch off from the single gas exchange conduit. The connector portion can then be connected, for example by a three-way safety connector, to the second patient interface 220 for delivering high-flow respiratory assistance.

[0301] Retention mechanism In some embodiments, at least some of the conduits are arranged coaxially such that the outer wall of the inner lumen defines the inner wall of the next lumen, as shown diagrammatically in FIG. 21. In other embodiments, at least some of the conduits are arranged in parallel, and the multi-lumen assembly 1400 includes a mechanism for holding at least some of the conduits in a mass, such as in a strip (FIG. 22A) where the conduits are arranged side-by-side, or in a bundle (FIGS. 22B and 22C). In some embodiments, the conduits are configured to be plugged into three respective "slots" of the respiratory assistance system 1000 to deliver anesthesia and / or ventilation, as well as high-flow respiratory assistance, depending on the selected operating mode of the system. Using a patient-end adapter, the first and second patient interfaces can be plugged into a single connector (e.g., connector 1500), or the conduits can be separated along a portion of the assembly to allow independent movement of the patient ends.

[0302] In some embodiments, the retention feature includes webbing 1452 disposed between at least pairs of the plurality of conduits, spaced apart along at least a portion of the plurality of conduits arranged in a strip or in series. The webbing (or webbing portion) 1452 may be breakable to facilitate separation of at least a portion of one or more of the plurality of conduits from the mass, for example to separate a second inhalation conduit 1420 coupled to the second patient interface 220, whereas the first inhalation and exhalation conduits are coupled to a single first patient interface 120.

[0303] Alternatively or additionally, the retention mechanism may include a sheath (or skin) 1454 applied around the multiple conduits, as shown in FIG. 22B. Ideally, a portion of the sheath 1454 is removable from a portion of the multi-lumen assembly, for example to separate the second inhalation conduit 1420. The sheath may be formed from any suitable material, such as a plastic extrusion or wrap that may have a continuous sheet form, be a woven fabric, or an expandable "mesh" that may be stretched over the multiple conduits. One advantage of a sheath 1454 formed from a smooth plastic or similar coating is that it is easily cleaned by wiping and has a neat appearance. Advantageously, the patient interface may be replaced, especially when used with a filter 230 that may be assembled with or incorporated as part of the patient interface being used. This allows the three lumen tube assembly 1400 to be reused on different patients. Alternatively or additionally, the filter 230 may be incorporated into or coupled to the three lumen tube assembly 1400, allowing a single filter to be used with different interchangeable patient interfaces. Additionally, the three lumen tube assembly 1400 also has the capability to carry a sensor wire or gas sampling line 227, which may be utilized to transmit sampled exhaled gas or sensor signals from a sensor located in a patient interface (such as a second patient interface in the form of a nasal cannula) to a controller 1010 of the respiratory assistance system 1000, which may be used to control switching between operational modes of the respiratory assistance system 1000, as described herein.

[0304] Alternatively or additionally, the retention mechanism may include one or more retainers or clips 1456 configured to hold two or more of the conduits in a cluster. FIG. 22C shows an example of a retainer / clip 1456 with slots to hold three conduits in a cluster or bundle. It should be understood that several retainers 1456 may be used to hold the bundle of conduits together along a desired length. In some embodiments, the retainer / clip 1456 may provide slots to accommodate two, three, four or more conduits and may have slots to hold, for example, a sensor wire or other elongated member. In some embodiments, the retainer 1456 is slidable along a portion of one or more of the conduits in the conduits. An advantage of the retainers 1456 is that their position on the multi-lumen assembly 1400 can be changed as needed, not all slots need to be used, and they can be cleaned and reused. They can also be used to rejoin conduits that were previously separated when a web or sheath was provided.

[0305] In some embodiments, the multi-lumen assembly 1400 includes or is operable with a flow switching mechanism operable to direct the flow of breathing gas to the first inhalation conduit 1410 or the second inhalation conduit 1420. The switching mechanism is operable by a user to select an assistance mode, which determines the flow of breathing gas to the first or second inhalation conduit. The switching mechanism is associated with or operably coupled to the respiratory assistance system 1000 and may take any suitable form, such as a button, switch, knob, foot operated switch or pedal, or other user operable actuator. In the illustrated embodiment, the switching mechanism is shown diagrammatically as a switch lever 700.

[0306] In some embodiments, the switching mechanism is operatively coupled to the respiratory assistance system controller 1010 by electronic means that allows the user to switch between modes by using a touch screen or other electronic interface. In some embodiments, the switching mechanism may be directly coupled to the gas flow diverter that controls the flow to the first gas outlet 1044 and the second gas outlet 1048 of the system. Alternatively, an electronic switching mechanism with functional control over the valves and / or gas flow diverters or other means used to control the flow of gas to the first inhalation line 1410 and the second inhalation line 1420 provides scope for flexibility in the location of the switching mechanism as well as the possibility of central control over other components of the respiratory assistance system 1000 such as vaporizers, gas sources, gas mixers, flow regulators, etc.

[0307] 24 illustrates an example of a patient end connector 1500 that can be coupled to a three lumen assembly 1400 via a connector coupling 1550. In some embodiments, the patient end connector 1500 includes one or more switching elements 1570 that are user operable to switch the connector between a first mode of operation in which the connector directs respiratory gases to a first patient interface via a first coupling 1510 and expiratory gases from the patient to an expiratory flow path via an expiratory coupling 130, and a second mode of operation in which the connector directs respiratory gases to a second patient interface via a second coupling 1520. The switching element 1570 is thus in operative communication with the controller 1010 of the respiratory assistance system 1000 to communicate the selected mode such that the gas delivery system can be configured accordingly. Alternatively / additionally, the controller 1500 can receive control signals from the system controller 1010 to redirect flow within the controller and direct respiratory gases to the first or second patient interface, for example by activating valves and / or gas flow diverters.

[0308] In various embodiments of the multi-lumen assembly 1400 and actuators and connectors used with or forming part of the multi-lumen assembly, a gas sampling conduit 227 (FIG. 22B) may be provided for monitoring one or more properties of a gas, such as CO. These properties may be used by the respiratory assistance system controller to determine whether a first or second patient interface is attached to the connector and applied to the patient's airway.

[0309] CO2 triggered system switching Another aspect of the disclosure relates to CO2 sensing as a means of providing mode switching in a system for delivering respiratory gas to a patient. This aspect will be described in relation to a system 1000 for providing respiratory assistance as described herein. The system is operable to deliver respiratory gas via a first patient interface 120 in a first mode and via a second patient interface 220 in a second mode. The system includes one or more CO2 sensors configured to detect CO2 in exhaled gas from the patient. A system controller 1010 receives input from the one or more CO2 sensors and operates a system switching mechanism according to the detected CO2 to select the first mode when the detected CO2 indicates that the first patient interface is connected to the patient and to select the second mode when the detected CO2 indicates that the second patient interface is connected to the patient.

[0310] In some embodiments, the system controller 1010 switches control if it determines that there has been a change in the detected CO2 concentration. However, detection of a change need not be mandatory, as a comparison with a reference value (e.g., corresponding to a typical ambient CO2 level) may be sufficient for the controller to determine whether the first patient interface 120 or the second patient interface 220 is attached to the patient. Detection of a patient circuit (and patient interface) connected to the patient allows the system controller 1010 to automatically select the correct operating mode for providing the required respiratory assistance to the patient. For example, in a first mode, respiratory gas is delivered to the patient's airway via the first patient interface, which may be a sealing interface, and exhaled gas is returned to the system by an exhaled gas flow path. The exhaled gas may be redirected to the atmosphere or exhaust, for example, when the respiratory gas is delivered to the patient in the first mode to provide ventilation assistance. Alternatively, the first mode may be a rebreathing first mode, in which the exhaled gas returned to the system is recirculated via a rebreathing system as disclosed herein for delivery to the patient via the first patient interface. In a rebreathing first mode, the breathing gas may include one or more volatile anesthetic agents vaporized therein by a vaporizer as disclosed herein. In a second mode, the breathing gas may be delivered at a higher flow rate of at least 20 LPM (for an adult) and up to about 90 LPM, and these gases may be delivered to the patient via a second patient interface 220, which may be a non-sealing interface such as a nasal cannula 224.

[0311] The system may include a CO2 sensor associated with a first breathing circuit for delivery of breathing gas in a first mode and / or a second breathing circuit for delivery of breathing gas in a second mode, and the controller 1010 may determine the breathing circuit containing the highest concentration of CO2 to be the breathing circuit attached to the patient and control the delivery of gas to the determined breathing circuit according to the associated operating mode.

[0312] Typically, when one or more CO2 sensors detect CO2 in the exhaled gas in the exhaled gas flow path 130 that returns the exhaled gas to the system, the system controller 1010 determines that a first breathing circuit including a first patient interface 120 is attached to the patient. The first patient interface 120 may include a sealing mask 124 or an endotracheal tube 126, as shown in Figures 25 and 26, with a CO2 sensor (not shown) in the gas flow path of the exhaled gas conduit that returns the exhaled gas to the system. The CO2 sensor may be located in the system body, for example at the exhaled gas inlet or anywhere along the length of the exhaled gas conduit 130. The nasal cannula 224 shown in Figures 25 and 26 has nasal prongs 226 that can direct high flow respiratory gas to the nasal passages of the patient 300.

[0313] Since the non-sealing patient interface does not have a return conduit for exhaled gases, the CO2 sensor can be located at the patient end of the interface, for example on the prong 226 or on the cannula body to which the prongs are attached. Alternatively, a sampling conduit 228 can be used to return sampled gases exiting the nasal cavity to a CO2 sensor located elsewhere in the device. Thus, the sampling conduit 228 can be connected to a gas sampling line 227 (FIGS. 27 and 28) that is in fluid communication with a CO2 sensor that provides an input to the system 1000, or can be in fluid communication with the exhaled gas conduit 130 as shown in FIG. 26. Because CO2 dissipates quickly into the atmosphere, in embodiments in which exhaled gases are directed via the sampling conduit 228 to the exhaled gas conduit 130, the controller 1010 can be configured to associate lower detected CO2 concentrations with the use of the second non-sealing patient interface 220 / 224.

[0314] The sampling conduit 228 may provide flow to the expiratory gas conduit 130 or may provide a separate conduit in fluid communication with a dedicated gas sampling inlet of the system 1000. FIG. 26 shows the cannula 224 and the face mask 124 coupled to the expiratory gas conduit 130 (for simplicity, the inhaled gas conduit 110 is not shown). The sampling conduit 228 directs expiratory gas from the patient's mouth to the expiratory gas conduit 130 to be detected by the CO2 sensor. In this arrangement, the nasal cannula 224 may be used to deliver respiratory gases, which may include anaesthetic agents, in a first mode in which the mask provides a means to direct expiratory gases through the expiratory pathway 130. In some embodiments, the sampling conduit 228 may be disconnected from the expiratory gas conduit of the sealing mask 124 and coupled to the expiratory gas conduit of the endotracheal tube 126 (or vice versa), allowing detection at various stages of sedation, including induction, ongoing anesthesia with ventilation, and weaning.

[0315] A variety of different approaches to sensing as a means of providing mode switching in a system that delivers respiratory gas to a patient can be used. In one example, pressure in the mask can be monitored with a pressure sensor and used to detect when the mask is in place on the patient. The mask may be placed over a high-flow cannula (as in FIG. 32) or may replace the cannula. Detecting the presence of the mask on the patient can be accomplished by detecting a rise in pressure from that expected during delivery of high-flow respiratory assistance (consistent with the mask being placed over the cannula), indicating that a rebreathing circuit may be intended to be used, which can switch operation of the respiratory assistance system 100 from high-flow mode to rebreathing mode. Additionally or alternatively, the mask can be provided with a light sensor configured to monitor a change in emitted / detected light that occurs in the presence of the patient's skin and can be used to detect when the mask is placed on the patient. This can be used in conjunction with a pressure sensor in the mask cuff that detects a rise in pressure when the mask is applied to the patient, which can trigger a switch of control from high-flow mode to rebreathing mode. Similarly, if an opposite change is detected in these measurements, this may coincide with the mask being removed from the patient, which may trigger a switch of control from rebreathing mode to high flow mode.

[0316] Alternatively or additionally, sensing of the expiratory flow path of the rebreathing tube can be used to determine when the mask is in place on the patient to trigger a switch to rebreathing. The mask may be placed over the high flow cannula (as in FIG. 32) or may replace the cannula. One or more parameters in the expiratory flow path, such as flow rate, pressure, temperature or humidity, can be determined using suitable sensors. An increase in one or more of these parameters (e.g., if a sensor determines that the temperature in the expiratory flow path has increased or is higher than ambient) indicates that the mask is on the patient and triggers a switch from high flow to rebreathing mode.

[0317] 27 and 28 show another arrangement utilizing a piston-driven assembly to selectively direct exhaled gases from each of a first patient interface (mask 124) and a second patient interface (nasal cannula 224) to a gas sampling line 227. A sampling conduit 228 collects exhaled gases from the nasal cannula 224 into a first chamber 231A of the assembly. The assembly is housed with a filter 230 (which may be omitted) that receives exhaled gases from the face mask 124 and directs them through an opening 233 to the first chamber 231A. A second chamber 231B is adjacent to the first chamber and is in fluid communication with the air-filled cuff 125 of the mask 124. A piston 232 is movable between the two chambers 231A, 231B between a first position (FIG. 27) and a second position (FIG. 28). The first position prevents the flow of gas from the sampling conduit 228 to the gas sampling line 227, and exhaled gas from the mask 124 is received through the filter 230 and the opening 233 into the first chamber 231A and directed to the gas sampling line 227 (FIG. 27). The second position prevents the flow of exhaled gas from the mask 124 to the gas sampling line 227, and exhaled gas from the sampling conduit 228 is directed to the gas sampling line 227 (FIG. 28). When the mask 124 is applied to the patient's face to deliver respiratory gas in the first mode, pressure increases in the cuff 125 and the piston 232 shifts away from the cuff to the first position. When the mask 124 is removed from the patient's face, the biasing means 234 shifts the plunger to the second position. The biasing means 234 is shown in the figures as a resilient biasing means, but it should be understood that the movement of the plunger may be controlled electronically, mechanically, or in other ways.

[0318] In another arrangement shown in Figures 29A and 29B, airway pressure as determined by pressure within the mask itself is used to selectively direct exhaled gases to a gas sampling line 227. Figure 29A shows the arrangement while the mask is being used in a first mode, and Figure 29B shows the arrangement while a nasal cannula (not shown) is being used. The gas sampling line 227 has a lower pressure than both the expiratory conduit 130 from the face mask and the sampling conduit 228 from the nasal cannula. In Figure 29A, positive pressure within the mask while in use in the first mode causes the pressure responsive flow diverter 235 to pass the flow of exhaled gases from the expiratory conduit 130 to the gas sampling line 227, while blocking the flow of exhaled gases from the sampling conduit 228 (from the nasal cannula). In Figure 29B, the mask is removed from the patient and the pressure in the expiratory conduit 130 is equalized to atmospheric pressure. During the second mode of operation, a nasal cannula is applied to the patient, and the expiratory gas in the sampling conduit 228 builds up pressure, and the flow diverter 235 passes the flow of expiratory gas from the sampling conduit 228 to the gas sampling line 227, while substantially preventing the flow of expiratory gas from the expiratory conduit 130 due to the pressure differential and the positioning of the flow diverter 235 when operating in the second mode.

[0319] In yet another arrangement shown in FIG. 30, a user actuates a three-way switch 1600 to selectively direct exhaled gas from one of a nasal cannula, an endotracheal tube, and an occlusive mask to a gas sampling line 227, which in a preferred embodiment is incorporated into the multi-lumen assembly 1400. A piston 232, coupled to a user-operated actuator, moves within a chamber 231 inside the switch housing to direct the exhaled gas flow according to the operating mode or patient interface selected by the user. When the piston moves to the most distal position of the multi-lumen tube assembly 1400, high pressure exhaled gas from the cannula (via sampling conduit 228) enters the chamber 231 inside the multi-lumen assembly and the gas sampling line 227. When the piston shifts toward the multi-lumen tube assembly 1400, flow from the cannula cannot enter the gas sampling line, and instead exhaled gas enters from one of the endotracheal tube or mask.

[0320] In some embodiments, the system 1000 includes a first respiratory device 100 for delivering respiratory gas in a first mode and a second respiratory device 200 for delivering respiratory gas in a second mode, as described herein. The first respiratory device 100 can thus include one or more of a CO2 absorber configured to process the returned exhaled gas in the first mode before recirculating it to the patient, a pressure limiting valve configured to maintain a substantially stable pressure in the system in the first mode, a variable volume (such as a ventilation bag or bellows) for gas replacement in the first mode, a fresh gas flow to supplement the anesthetic gas delivered to the patient in the first mode, and a vaporizer to vaporize a volatile anesthetic agent into the respiratory gas delivered to the patient in the first mode. The second respiratory device 200 includes a flow regulator configured to provide a high flow rate of gas through the system, and typically includes a humidifier configured to condition the respiratory gas to a predetermined temperature and / or humidity before delivery to the patient in the second mode.

[0321] In a preferred embodiment, when the second mode is selected, the system isolates the flow of respiratory gas from the first respiratory apparatus to the patient, ensuring no anesthetic agent is delivered to the patient 300. In some embodiments, the first respiratory apparatus 100 and the second respiratory apparatus 200 are integrated into an integrated machine, although this is not required. In either case, a humidifier may be provided to condition the respiratory gas to a predetermined temperature and / or humidity before delivery to the patient in the second mode.

[0322] In some embodiments, the system 1000 includes a display device or monitor 1094 in operative communication with the system controller 1010 and configurable to display one or more CO2 traces based on input from one or more CO2 sensors received by the system controller. The system controller 1010 can automatically determine which of the CO2 sensor signals to display on the monitor 1094, and select the trace corresponding to the CO2 sensor input that represents the highest detected CO2 value from the multiple CO2 sensors, or the CO2 value that is most likely to be similar to the patient value (e.g., higher than the ambient CO2 concentration). Alternatively, the system controller 1010 can display all CO2 traces simultaneously or in a cyclical manner on the monitor 1094, or on one or more separate monitors that may be dedicated to CO2 monitoring.

[0323] Humidified breathing apparatus 38-40 show a respiratory apparatus 100 for delivering respiratory gas to a patient 300, according to one embodiment of the present disclosure. The respiratory apparatus 100 includes a flow source 1030 that provides a flow of respiratory gas for delivery to the patient 300 in an inhalation flow path. The respiratory apparatus 100 also includes a mount 160 that couples to at least one vaporizer 150 that vaporizes one or more volatile anesthetic agents prior to delivery to the patient 300 in the flow of respiratory gas in the inhalation flow path. The respiratory apparatus 100 also includes a return flow path that recirculates exhaled gas received from the patient 300 via the exhalation flow path to the inhalation flow path. The mount 160 is coupleable to a humidification component 450 that conditions the flow of respiratory gas in the inhalation flow path to a predetermined temperature and / or humidity prior to delivery to the patient 300.

[0324] Components of the respiratory apparatus 100 as shown and described in connection with Figures 38-40 that have similar numbering to components of the anesthesia machine 10, ventilator 20 and high-flow system 30 are intended to refer to the same components. Thus, the descriptions of these components in connection with the anesthesia machine 10 are believed to be applicable to the respiratory apparatus 100 according to some embodiments of the present disclosure.

[0325] The flow source 1030 of the respiratory apparatus 100 may include a flow regulator (such as the flow regulator 250 described with reference to FIG. 2), more particularly a flow generator adapted to receive one or more respiratory gases external to the respiratory apparatus 100 and generate a gas flow through the respiratory apparatus 100. The flow generator may be in direct or indirect fluid communication with a gas supply 1060 that provides one or more respiratory gases to the respiratory apparatus 100. The gas supply 1060 may be a gas source supplied by one or more hospital gas outlets, such as those located in an operating room or an ICU. The gas supply 1060 may be configured to supply nitric oxide (NO), oxygen (O2) and / or air to the flow generator.

[0326] In some embodiments, the flow source 1030 includes a gas supply 1060. The flow source 1030 and / or the respiratory apparatus 100 may include one or more valve arrangements adapted to control the rate at which one or more gases, e.g., one or more of NO, O2 and air supplied from the gas supply 1060, are provided to the inhalation flow path. This may also allow for control of mixing the one or more gases into a desired composition for use by the respiratory apparatus 100. In alternative embodiments, the flow source 1030 may not include a gas supply 1060. Instead, the flow source 1030 may include one or more containers of compressed air and / or another gas, and one or more valve arrangements adapted to control the rate at which the gas exits the one or more containers to provide a flow of respiratory gas to the inhalation flow path.

[0327] In other embodiments, the respiratory apparatus 100 is in gas flow communication with a gas delivery device 1040, which is in fluid communication with a gas supply 1060, as indicated by the dashed lines shown in FIG. 38. The gas delivery device 1040 may receive a supply of gases including one or more of NO, O2, and air from the gas supply 1060. The gas delivery device 1040 includes a gas mixing element 1042 that blends one or more of NO, O2, and air from the gas supply 1060 in a ratio required to deliver respiratory gases in a desired ratio for use by the respiratory apparatus 100. For example, when the respiratory apparatus 100 is operating to provide anesthesia ventilation with one or more anesthetic agents to the patient 300, the gas mixing element 1042 may include at least nitric oxide (NO) in the respiratory gas provided to the respiratory apparatus 100. Alternatively, when the respiratory apparatus 100 is operating to provide anesthesia ventilation to the patient 300 without anesthesia, the gas mixing element 1042 may include O2 and / or air.

[0328] The gas delivery apparatus 1040 also includes one or more flow meters 1090 that control the flow of respiratory gases provided to the respiratory apparatus 100, as shown in FIG. 38. The gas delivery apparatus 1040 may include flow meters 1090 that control gas lines delivering each of NO, O2, and air (see, for example, FIGS. 54 and 55, which include flow meters 190 on the respiratory apparatus 100). The flow meters 1090 may control the gas mix by varying the flow rate of each of the respiratory gases provided to the respiratory apparatus 100, and thereby the proportion of the respiratory gases. The gas delivery apparatus 1040 may also include a gas outlet 1044 that is connectable to the respiratory apparatus 100 to supply gas from the gas delivery apparatus 1040 to the respiratory apparatus 100.

[0329] In other embodiments, the respiratory apparatus 100 may include a gas delivery device 1040. The gas delivery device 1040 may be in fluid communication with the flow source 1030 to provide breathing gas to the flow source 1030 to generate a flow of gas in the inhalation flow path for delivery to the patient 300. Alternatively, the gas delivery device 1040 may replace the flow source 1030 such that a gas outlet 1044 provides a flow of breathing gas directly to the inhalation flow path.

[0330] The respiratory apparatus 100 provides an inhalation flow path in which a flow of respiratory gas is directed to the patient's airway 310. The flow of respiratory gas from a flow source 1030 may be conditioned and / or modified in the inhalation flow path before being delivered to the patient 300. As shown in FIG. 38, the flow of respiratory gas may be directed from the flow source 1030 (or gas supply 1060 and / or gas delivery device 1040) to a vaporizer 150, to a humidification component 450 external to the respiratory apparatus 100, or directly to the inhalation conduit 110 or the inhalation conduit 120. The options for directing the flow of respiratory gas may be controlled by a controller 1010 of the respiratory apparatus 100. Additionally, a switching mechanism 1020 may be provided to control switching between options for directing the flow of respiratory gas in the inhalation flow path, as will be described in more detail in relation to FIG. 52 and FIG. 49.

[0331] The respiratory apparatus 100 can be operated in a number of operating modes, for example by the controller 1010. The respiratory apparatus 100 can be operable in a first mode in which the respiratory apparatus 100 delivers respiratory gas to an inhalation flow path and receives exhalation gas return via an exhalation flow path. The first operating mode can be an anesthesia ventilation mode, which can include providing ventilatory support with or without one or more anesthetic agents. Typically, the respiratory gas is delivered at a low flow rate, for example less than about 15 L / min. In the first mode, the respiratory gas can include one or more of NO, O2 and air. The respiratory gas can optionally include one or more anesthetic agents, such as nitric oxide from the flow source 1030 and / or one or more volatile agents from the vaporizer 150, for operation of the respiratory apparatus 100 in the anesthesia ventilation mode.

[0332] In a first mode, the flow of breathing gas can be directed from the flow source 1030 to the vaporizer 150 or directly to the inhalation conduit 110 for delivery to the patient 300 as shown in FIG. 38. When the flow of breathing gas is directed to at least one vaporizer 150, the flow of breathing gas can be modified to optionally include one or more volatile anesthetic agents that vaporize in the gas flow. The one or more volatile anesthetic agents can include isoflurane or sevoflurane that are converted from a liquid to a vapor by the vaporizer 150. The flow of breathing gas including any anesthetic agents is then directed to the inhalation conduit 110 for delivery to the patient's airway 310 via the first patient interface 120. The first patient interface 120 can form a sealed interface with the patient's airway 310 and can include a mask or an endotracheal tube. The first patient interface 120 can include a laryngeal mask airway (LMA) or a sealing face mask.

[0333] The respiratory apparatus 100 also provides an expiratory flow path through which a flow of expiratory gas is received from the patient 300. The first patient interface 120 may be configured to receive expiratory gas from the patient 300 in a first mode, as shown in FIG. 38. The expiratory gas may flow through an expiratory conduit 130 coupled to a rebreathing component 140 of the respiratory apparatus 100. The rebreathing component 140 includes at least a CO2 absorber 141 configured to process returned expiratory gas from the patient 300 in the first mode before recirculating it to the inhalation flow path. The rebreathing component 140 may also include one or more of a ventilation bag 142, a pressure relief valve 143, a scavenger system 144, a bellows 145, and a pressure relief valve 146, as described in relation to the anesthesia machine 10 of FIG. 1A. Thus, the respiratory apparatus 100 provides a return flow path in the first mode for recirculating expiratory gas from the patient 300 to the inhalation flow path via the rebreathing component 140.

[0334] The respiratory apparatus 100 may also be operable, for example by the controller 1010, in a second mode in which the respiratory apparatus delivers respiratory gas to the inhalation flow path at a predetermined flow rate without return of exhaled gas from the patient 300. The second mode may be a high-flow mode in which high-flow respiratory assistance is delivered. Typically, the respiratory gas is delivered at a high flow rate, such as in the range of about 20 L / min to about 90 L / min, or in the range of about 40 L / min to about 70 L / min. In other embodiments, the predetermined flow rate may include about 20 L / min, about 40 L / min, or about 70 L / min. The respiratory gas may include a proportion of O2 and / or air required for operation of the respiratory apparatus 100 in the second mode.

[0335] In the second mode, a flow of respiratory gas may be directed from the flow source 1030 to the humidification component 450, which is then provided directly or indirectly to the second inhalation conduit 210 for delivery to the patient 300, as shown in FIG. 38. When the flow of respiratory gas is directed to the humidification component 450, the humidification component 450 is operable to condition the flow of respiratory gas in the inhalation flow path to a predetermined temperature and / or humidity before delivery to the patient 300. The humidification component 450 may be operable to heat the flow of respiratory gas to a predetermined temperature. The predetermined temperature and / or humidity may include a temperature and / or humidity value or range of values ​​suitable for delivery of ventilation assistance, particularly high-flow respiratory assistance, to the patient 300. However, it should be understood that in some embodiments, it may be desirable to not only enable the vaporizer 150, but also to enable the humidification component 450 to provide humidification and / or warming of the gas during delivery of assistance in the first mode, i.e., rebreathing mode.

[0336] The humidification component 450 can operate in at least an invasive mode (e.g., for a patient with a bypassed airway) and / or a non-invasive mode (e.g., for a patient or user with a respiratory mask or nasal cannula). Each mode can have multiple humidity settings, which can be expressed as dew point or absolute humidity. The humidification component 450 can be controlled to deliver humidified gas at the outlet port 408 of the humidification chamber 400 and / or the patient end of the inhalation conduit 210 at or near a predetermined humidity level dew point (or absolute humidity). For example, a user or clinician can select a setting appropriate for the current mode of operation. Multiple humidity settings can be provided. For example, the humidity settings can correspond to dew points of 37° C., 31° C., 29° C., 27° C., etc. A humidity setting corresponding to a dew point of 37° C. may be suitable for invasive therapy (i.e., when the patient's upper airway is bypassed), while other humidity settings may be suitable for non-invasive respiratory assistance, although the humidity settings may not be limited to a particular type of respiratory assistance. Alternatively, each humidity setting may be continuously variable between an upper and lower limit. A user or clinician may select a lower humidity setting to reduce condensation or "rainout" in the inhalation conduit 210, or a higher humidity setting to improve patient comfort or physiological benefit. Some of the humidification components 450 disclosed herein may also include a high-flow mode, a non-sealed mode, or any other mode known to one of skill in the art.

[0337] The humidification component 450 can provide different humidity levels for different respiratory assistance applications. For example, the humidification component 450 can deliver a desired humidity level of about 44 mg / L BTPS (about 37° C. fully saturated) for invasive and / or high-flow respiratory assistance, and / or about 32 mg / L BTPS (about 31° C. fully saturated) for non-invasive forms of respiratory assistance. Other suitable patient comfort settings can also be delivered for various forms of respiratory assistance.

[0338] The flow of conditioned breathing gas from the humidification component 450 can be directed to the second inhalation conduit 210 and to the second patient interface 220, which can be coupled to the patient's airway 310. The second patient interface 220 can form a non-sealing interface with the patient's airway 310 and can include a nasal cannula. Alternatively, the flow of conditioned breathing gas can be returned to the respiratory apparatus 100 and then exit through a dedicated outlet 164 for delivery to the patient 300 (see also FIG. 39). In this case, the second inhalation conduit 210 can be coupled to the outlet 164 to deliver the flow of conditioned breathing gas to the patient's airway 310. Additionally / alternatively, the respiratory apparatus 100 can also allow the flow of conditioned breathing gas from the humidification component 450 to be directed to the first inhalation conduit 110 in the first mode of operation. Thus, some humidification functionality can be utilized in the first mode of operation if desired by the anesthesiologist or clinician.

[0339] Importantly, in some embodiments, the respiratory apparatus 100 does not allow a flow of respiratory gas containing an anesthetic agent to be directed to the patient 300 in the second mode. Operation of the humidification component 450 can prevent the delivery of one or more volatile anesthetic agents into the flow of respiratory gas in the inhalation flow path. More specifically, operation of the humidification component 450 can disable operation of at least one vaporizer 150, or all of the vaporizers 150, in the respiratory apparatus 100. For example, the respiratory apparatus 100 can include a one-way valve or other arrangement that prevents gas flow, and in particular the passage of any volatile anesthetic agent, from the vaporizer 150 to the second inhalation conduit 210 when the humidification component 450 is operating. Such arrangements are described above.

[0340] Respiratory apparatus 100 may advantageously enable selective operation of one or more of vaporizer 150 and humidification component 450. Respiratory apparatus 100 may include an optional switching mechanism 1020 as shown in Figure 38 to enable selective operation of vaporizer 150 or humidification component 450, with gas flow being directed to inlet conduit 110 or inlet conduit 210 as shown when neither is selected. Switching mechanism 1020 may be configured to operate depending on the operating mode of respiratory apparatus 100, as will be described in further detail.

[0341] Figures 39 and 40 show additional components of a respiratory apparatus 100, illustrated as an anesthesia machine, having similar features as the anesthesia machine 10 shown in Figure 1A. The respiratory apparatus 100 may include a module 180 having an auxiliary O2 flow meter and a suction regulator. The respiratory apparatus 100 may also be configurable to be in gas flow communication with one or more flow meters 190 (see also Figures 54 and 55) similar in operation to the flow meter 1090 of the gas delivery device 1040 illustrated and described in relation to Figure 38, to control the flow / mix of gases within the respiratory apparatus 100. The respiratory apparatus 100 may be configurable to be in gas flow communication with the flow meter 190 to control the flow of gases including one or both of air and O2 in a second mode.

[0342] The respiratory apparatus 100 may be configurable in gas flow communication with one or more of: a pressure limiting valve 143, 146 configured to maintain a substantially stable pressure within the respiratory apparatus 100 in the first mode; a variable volume or bellows 145 for displacement of gas in the first mode; a fresh gas flow (FGF) (see also Figs. 56 and 57) for supplementing the respiratory gas delivered to the patient 300 in the first mode; and a vaporizer 150 for vaporizing one or more volatile anesthetic agents into the flow of respiratory gas before delivery to the patient 300 in the first mode. See also, for example, the components of the anesthesia machine 10 in Fig. 1A. The respiratory apparatus 100 may also include two monitors, a patient monitor 192 and a system monitor 194, for displaying information useful to an operator of the respiratory apparatus 100.

[0343] The respiratory apparatus 100 also includes a mounting base 160 that is connectable with the vaporizer 150 and the humidification component 450, as shown in FIG. 39. The mounting base 160 may include a number of slots that receive the housings of the vaporizer 150 and the humidification component 450. The housings of the vaporizer 150 and the humidification component 450 may be slidably received in the slots of the mounting base 160. FIG. 40 illustrates an empty slot in the mounting base 160 when the humidification component 450 is removed. The mounting base 160 may be such that at least one vaporizer 150 and the humidification component 450 are mountable adjacent to one another on the respiratory apparatus 100, as shown in FIG. 39. The vaporizer 150 and the humidification component 450 may be positioned in a side-by-side arrangement on the mounting base 160. As described in connection with FIGS. 46-51, the housings of the vaporizer 150 and the humidification component 450 or components thereof may cooperatively engage with one another.

[0344] In some embodiments, the mount 160 can be coupled to two or more vaporizers 150 (not shown) in addition to the humidification component 450. The humidification component 450 can be positioned on the mount 160 with a vaporizer 150 on either side of the humidification component 450. This allows the housing of the humidification component 450 to cooperatively engage with each of the housings of the vaporizers 150, such as disabling operation of both vaporizers 150 when the humidification component 450 is operating, as will be described in more detail in connection with FIGS. 46-51. The mount 160 can also include a heating element 162, shown as a heating coil in FIG. 40, which will be described in more detail in connection with FIG. 43. However, the heating element 162 is optional and need not be included in the mount 160.

[0345] 41-44 show different embodiments of a humidification component 450 for use with a respiratory apparatus 100 for delivering respiratory gas to a patient 300, according to some preferred embodiments of the present disclosure. The respiratory apparatus 100 includes a flow source 1030 for providing a flow of respiratory gas to an inhalation flow path for delivery to the patient 300. The respiratory apparatus 100 also includes a mount 160 for coupling with at least one vaporizer 150 for vaporizing one or more volatile anesthetic agents into the flow of respiratory gas in the inhalation flow path before delivery to the patient 300. The respiratory apparatus 100 also includes a return flow path for recirculating exhaled gas received from the patient 300 via the exhalation flow path to the inhalation flow path. The humidification component 450 is coupleable with the mount 160 of the respiratory apparatus 100 for conditioning the flow of respiratory gas in the inhalation flow path to a predetermined temperature and / or humidity before delivery to the patient 300.

[0346] The humidification component 450 may be configured for use with the respiratory apparatus 100 of Figures 38-40 and as described in the embodiments herein. Accordingly, the description of the components of the respiratory apparatus 100 will not be repeated again for the sake of brevity. The humidification component 450 may include a humidification chamber 400 as shown in Figures 39 and 41-44 through which respiratory gas is received and conditioned to a predetermined temperature and / or humidity. For example, in the embodiment of Figure 39, the humidification chamber 400 may be integrated into the housing of the humidification component 450 and / or may be a replaceable component. The humidification chamber 400 may be able to be refilled with liquid by a user. In some embodiments, the humidification chamber 400 may be configured to couple with the mount 160 and may be slidably received on the mount 160, such as via a housing 422 received in a slot in the mount 160. The humidification chamber 400 with the housing 422 is slidably receivable within the slot along a plane that is substantially horizontal to the mounting base 160 .

[0347] FIG. 41 illustrates one embodiment of a humidification component 450 including a housing 422 with a humidification chamber 400 through which respiratory gas is received from the respiratory apparatus 100 and conditioned to a predetermined temperature and / or humidity. The humidification chamber 400 includes an inlet port 406 for receiving a flow of respiratory gas from the respiratory apparatus 100 and a return port 408 coupleable to the respiratory apparatus 100 for returning the conditioned flow of respiratory gas. The humidification chamber 400 includes a heating element 404, such as a heating coil, that heats a liquid within the humidification chamber 400. The humidification chamber 400 is configured to be in electrical communication with the respiratory apparatus 100 for operation of the humidification chamber. The heating element 404 is electrically connected to the mounting 160 as shown in FIG.

[0348] 42 shows another embodiment of a humidification component 450 including a housing 422 containing a humidifier 420 having a humidification chamber 400, which is connectable to a humidification base unit 410 for operating the humidification chamber 400. The humidification chamber 400 may be slidably connectable to the humidification base unit 410. The humidification chamber 400 may be slidably connectable to be received along a substantially horizontal plane of the humidification base unit 410. For example, U.S. Patent No. 5,445,143 discloses a humidification chamber operating on a base in a substantially horizontal plane, which is suitable for embodiments of the present disclosure, the disclosure of which is incorporated herein by this reference.

[0349] In some embodiments, the humidification base unit 410 is configured to couple with the mount 160. The housing of the humidification base unit 410 may be configured to be slidably received on the mount 160. For example, the mount 160 may include a number of slots, one of which may slidably receive the housing of the humidification base unit 410, as shown by the mount 160 in FIG. 40. The humidification base unit 410 or its housing may be received in a similar slidable manner as the humidification component 450 described in connection with FIGS. 39 and 40.

[0350] The humidification chamber 400 includes an inlet port 406 for receiving a flow of respiratory gas from the respiratory apparatus 100 and an outlet port 414 for delivering a conditioned flow of respiratory gas to the patient 300. The outlet port 414 is connectable to an inhalation conduit 210 for delivering a conditioned flow of respiratory gas to the patient 300 via a patient interface (e.g., a sealed or non-sealed patient interface). The inhalation conduit 210 may be connected to a second patient interface 220, e.g., a nasal cannula, for delivering the respiratory gas to the patient's airway 310. The humidification base unit 410 includes a heating element 412, such as a heating coil, that heats the liquid in the humidification chamber 400. The heating element 412 of the humidification base unit 410 is electrically connected to the mounting 160, as shown in FIG.

[0351] Figure 43 shows another embodiment of a humidification component 450, similar to Figure 41, including a housing 422 having a humidification chamber 400 including an inlet port 406 and a return port 408. In this embodiment, the humidification chamber 400 includes a conductive plate 402 coupled with a heating element 404 in the mount 160, as shown in Figure 40. The conductive plate 402 heats up when the heating element 404 in the mount 160 is activated and transfers that heat to the humidification chamber 400 to heat the liquid in the humidification chamber 400.

[0352] FIG. 44 shows another embodiment of the humidification component 450 similar to FIG. 42. In this embodiment, the humidification chamber 400 includes a return port 408 that returns the flow of conditioned breathing gas to the breathing apparatus 100. The outlet port 414 is eliminated and cannot be coupled to the patient's airway 310. In this embodiment, the breathing apparatus 100 can include an outlet port 164, as shown in FIG. 39, through which the flow of conditioned breathing gas from the humidification component 450 is delivered to the inhalation flow path. The outlet port 164 can be coupled to the inhalation conduit 210 and deliver the flow of breathing gas to the patient's airway 310 via the second patient interface 220, as shown in FIG. 38.

[0353] In some embodiments, the humidification chamber 400 includes a liquid inlet that connects to a liquid reservoir to refill the humidification chamber 400. The humidification chamber 400 can also include a flow control mechanism that controls the flow of liquid into the humidification chamber 400. The humidification chamber 400 can include at least one sensor that detects the level of liquid in the humidification chamber 400. The humidification chamber 400 can include a float valve that controls the level of liquid in the humidification chamber 400. For example, U.S. Patent No. 5,445,143 discloses a dual float valve humidification chamber that is suitable for embodiments of the present disclosure, the disclosure of which is incorporated herein by this reference.

[0354] In some embodiments, the humidification component 450 is connectable to the mount 160 via an adapter 430. Figure 45 shows an exemplary adapter 430 connecting the humidification component 450 to a respiratory apparatus 100 that delivers respiratory gas to a patient 300. The adapter 430 may be connectable to the mount 160 of the respiratory apparatus 100. The adapter 430 may be received in a slot in the mount 160 in place of the vaporizer 150 or the humidification component 450.

[0355] 45, the adapter 430 includes a first inlet port 432 for receiving a flow of respiratory gas from the respiratory apparatus 100 and a first outlet port 433 for delivering the flow of respiratory gas to the humidification component 450. The adapter 430 further includes a second inlet port 434 for receiving a flow of conditioned respiratory gas from the humidification component 450. The flow of conditioned respiratory gas is delivered to the patient 300 or to the respiratory apparatus 100 via a second outlet port 435 of the adapter 430. In some embodiments, the second inlet port 434 and the second outlet port 435 are not required if the humidification component 450 directly couples with the inhalation conduit 210 to deliver the flow of conditioned respiratory gas to the patient's airway 310 (see, e.g., FIG. 42).

[0356] Figure 45 illustrates that the adapter 430 is configured to electrically connect to the respiratory apparatus 100 for operation of the humidification component 450. For example, the adapter 430 as shown in Figure 45 includes a first power connector 436 that electrically connects the adapter 430 to the respiratory apparatus 100. The adapter 430 also includes a second power connector 437 that electrically connects the humidification component 450 to the adapter 430. Thus, the humidification component 450 can be powered via the adapter 430 connected to the respiratory apparatus 100. However, it should be understood that the humidification may alternatively / additionally be configured to electrically connect to a battery or other on-board power source as would be understood by one of ordinary skill in the art.

[0357] Advantageously, in some embodiments of the present disclosure, operation of the humidification component 450 prevents delivery of one or more volatile anesthetic agents into the flow of respiratory gas in the inspiratory flow path. More specifically, operation of the humidification component 450 can disable operation of the at least one vaporizer 150, as described in connection with FIG. 38. The respiratory apparatus 100 can include an interlocking mechanism that prevents simultaneous operation of the humidification component 450 and the at least one vaporizer 150. The interlocking mechanism can be configured to enable operation of the humidification component 450 or the at least one vaporizer 150 when in an unlocked configuration and disable operation of the humidification component 450 or the at least one vaporizer 150 when in a locked configuration. FIGS. 46-49 show an exemplary interlocking mechanism of the respiratory apparatus 100 according to some embodiments of the present disclosure.

[0358] FIG. 46 illustrates a vaporizer 150 including a housing 152 having a dial 158 that provides an on / off switch when rotated by a user. The vaporizer 150 includes a locking element associated with the housing 152. The locking element 152 includes two locking pins 154A and 154B that are retractable into the housing 152 in a locked configuration and extendable from the housing 152 in an unlocked configuration. Each locking pin 154A and 154B may be independently retractable into the housing 152 in a locked configuration and extendable from the housing 152 in an unlocked configuration. In some embodiments, the locking element 152 may include only a single locking pin, such as locking pin 154B, as will be appreciated by those skilled in the art.

[0359] 47A-47C are schematic diagrams illustrating the operation of the interlocking mechanism of the vaporizer 150 of FIG. 46. In FIG. 47A, the dial 158 is rotated to the ON position and the locking pins 154A and 154B extend from the housing 152. In FIG. 47B, the dial 158 is rotated to the OFF position and the locking pins 154A and 154B retract toward the housing 152. In FIGS. 47A and 47B, the vaporizer 150 remains in an unlocked configuration in which the user can rotate the dial 158 between the ON / OFF positions to enable or disable operation of the vaporizer 150. In FIG. 47C, an external force is applied to the locking pin 154A such that the pin is fully retracted and no longer visible within the housing 152. This external force may be applied by a user or, more preferably, by a corresponding locking element associated with the housing 422 of the humidification component 450, as described below. In this state, the carburetor 150 is in a locked configuration where the dial 158 is then disabled and cannot be rotated between the on / off positions. The carburetor 150 is in a locked configuration with the dial 158 in the off position. The carburetor 150 can only be operated when the external force is removed and / or the locking pin 154A is released from within the housing 152.

[0360] FIG 48 shows the vaporizer 150 of FIG 46 positioned adjacent to a humidification component 450. The humidification component 450 includes a housing 422 having a dial 428 that provides an on / off switch when rotated by a user. The humidification component 450 includes a locking element associated with the housing 422. The locking element includes two locking pins 424A and 424B that are retractable into the housing 422 in a locked configuration and extendable from the housing 422 in an unlocked configuration. In some embodiments, the locking element includes only a single locking pin, such as locking pin 424A, as will be appreciated by those skilled in the art.

[0361] The vaporizer 150 and the humidification component 450 may include the same locking elements as shown in Figure 48. The vaporizer 150 and the humidification component 450 may be mountable adjacent to one another on the respiratory apparatus 100, such as by coupling adjacent to one another on a mounting base 160 as shown in Figure 39, to enable cooperation with one another. Thus, the vaporizer 150 and the humidification component 450 may be configured to cooperate with one another to provide an interlocking mechanism. Additionally, the locking elements of the vaporizer 150 or the humidification component 450 may be configured to engage with corresponding locking elements of the other of the vaporizer 150 or the humidification component 450 to provide an interlocking mechanism.

[0362] 49A and 49B are schematic diagrams showing the vaporizer 150 and humidification component 450 with the interlocking mechanism of FIG. 48. In FIG. 49A, the vaporizer 150 is switched to the ON position by rotating the dial 158, and the locking pins 154A and 154B extend from the housing 152. As the vaporizer 150 is positioned adjacent to the humidification component 450, the locking pin 154B of the vaporizer 150 presses against the locking pin 424A of the humidification component 450, retracting it into the housing 422 of the humidification component 450 and is not visible in FIG. 49A. In this state, the humidification component 450 is in a locked configuration in which the dial 428 is now disabled and cannot be rotated between the ON / OFF positions. The humidification component 450 is in a locked configuration in the OFF position. The humidification component 450 can only operate when the vaporizer 150 is turned off by rotating the dial 158 to the off position allowing the locking pin 424A to extend from the housing 422.

[0363] FIG. 49B shows the reversed configuration of the interlocking mechanism of FIG. 49A. In this embodiment, the humidification component 450 is switched to the ON position by rotating the dial 428, and the locking pins 424A and 424B extend from the housing 422. The locking pin 424A presses against the locking pin 154B of the vaporizer 150, causing it to retract with the housing 152 of the vaporizer 150 and is not visible in FIG. 49B. In this state, the vaporizer 150 is now in a locked configuration in which the dial 158 is disabled and cannot be rotated between the ON / OFF positions. The vaporizer 150 is in a locked configuration in the OFF position. The vaporizer 150 can only operate when the humidification component 450 is switched OFF by rotating the dial 428 to the OFF position, allowing the locking pin 154B to extend from the housing 422.

[0364] Advantageously, the locking elements of the vaporizer 150 and the humidification component 450 include a pair of locking pins, with a pin on each side of the housing of the vaporizer 150 and the humidification component 450. This is useful because the mount 160 can simultaneously receive one or more vaporizers 150 as well as the humidification component 450. If the humidification component 450 is positioned between two vaporizers 150, the locking pins 424A and 424B will retract one of the locking pins 154A and 154B of the two vaporizers 150 so that both vaporizers 150 can be disabled when the humidification component 450 is operating.

[0365] It should be understood that the humidification component 450 and the vaporizer 150 may be operable using manual or electronic switching control means to achieve various operating states, such as operation of the humidification component 450 being enabled while the vaporizer 150 is enabled, or operation of the humidification component 450 being disabled while the vaporizer 150 is enabled, or operation of the humidification component 450 being enabled while the vaporizer 150 is disabled, or operation of the humidification component 450 being disabled while the vaporizer 150 is disabled.

[0366] 50 and 51 show another interlocking mechanism according to some embodiments of the present disclosure. In FIG. 50 and 51, the vaporizer 150 and the humidification component 450 each include a slot associated with their respective housing. FIG. 50 and 51 exclude the respective housings for simplicity and show only the dial 158 of the vaporizer 150 and the dial 428 of the humidification component 450. The dials 158, 428 can be rotated by a user to switch the vaporizer 150 and the humidification component 450 to an on / off position. The dial 158 of the vaporizer 150 includes a slot 156 and the dial 428 of the humidification component 450 includes a slot 426. A locking pin 460 is slidably movable between the slots 156, 426 to provide the interlocking mechanism.

[0367] As shown in FIG. 51A, the locking pin 460 is positionable within the slot 426 of the humidification component 450 by sliding the pin 460 from the slot 156 to the slot 426. A user can manipulate the locking pin 460 to slide it between the slots 156, 426. In this state, the dial 428 cannot rotate due to the presence of the locking pin 460, and the humidification component 450 is in a locked configuration. The vaporizer 150 is in an unlocked configuration, and the dial 158 can rotate between the on / off positions. In FIG. 51B, the locking pin 460 is positionable within the slot 156 of the vaporizer 150. In this state, the dial 158 cannot rotate due to the presence of the locking pin 460, and the vaporizer 150 is in a locked configuration. In contrast, the humidification component 450 is in an unlocked configuration, and the dial 428 can rotate to the on position as shown, which prevents operation of the vaporizer 150.

[0368] In other embodiments, the interlocking mechanisms and locking elements as shown in Figures 46-51 can incorporate different mechanisms for operation, as will be appreciated by those skilled in the art. For example, the locking elements can include one or more resilient members or springs instead of locking pins. The locking elements can include other forms of mechanical interlocking components, such as levers, bars, latches and locks, to name a few.

[0369] FIG. 52 shows that the respiratory apparatus 100 can include a switching mechanism 1020 (not shown, see also FIG. 38 and FIG. 53) configured to enable selective operation of the humidification component 450 and at least one vaporizer 150. In some embodiments, the respiratory apparatus 100 can include more than one vaporizer 150, and the switching mechanism 1020 can selectively operate the more than one vaporizer 150, as well as the humidification component 450. Depending on the mode of operation, the switching mechanism 1020 can direct a flow of respiratory gas from the flow source 1030 (or from the gas delivery device 1040 as described above) to one of the vaporizers 150, the humidification component 450, or directly to the patient 300 via the first inhalation conduit 110 or the second inhalation conduit 120 (see also FIG. 38).

[0370] Activating the switching mechanism to operate the humidification component 450 may prevent operation of the vaporizers 150 until the switching mechanism is deactivated. Similarly, activating the switching mechanism to operate one of the vaporizers 150 may prevent operation of the humidification component 450 and / or the other vaporizers 150 until the switching mechanism is deactivated.

[0371] The switching mechanism 1020 may include one or more of a gas flow diverter, a bi-stable switch, a pneumatic switch, a rotary switch, a lever, a knob, or other user operable actuator. For example, the switching mechanism 1020 may include each of the vaporizer 150 and the humidification component 450 being operable by a switch. The switch may be a mechanical switch or an electronic switch. The switch may be a rotary switch that is user operable via rotation of the dial 158 on the vaporizer 150 and the dial 428 on the humidification component 450, as described in connection with Figures 46-51.

[0372] 53 is a schematic diagram illustrating mechanical interlocking switches of the vaporizer 150 and the humidification component 450 in the respiratory apparatus 100 according to some embodiments of the present disclosure. In this embodiment, the flow source 1030 includes a gas delivery device 1040 to which source gases are supplied via a gas supply 1060. The source gases include NO, O2, and air, which are then delivered through a gas mixing element 1042 and / or a flow meter 1090 to provide a desired composition and flow of respiratory gas within the respiratory apparatus 100. The flow of respiratory gas can then pass through either the vaporizer 150 or the humidification component 450 depending on whether the switch 158 or 428 is operable. The switches of the vaporizer 150 and the humidification component 450 can be coupled to prevent simultaneous operation of the humidification component 450 and the vaporizer 150.

[0373] The switching mechanism 1020 may also be coupled to an interlocking mechanism of the respiratory apparatus 100, as described in relation to Figures 46-51. When the switching mechanism 1020 is activated to operate the humidification component 450, the interlocking mechanism enables operation of the humidification component 450 via a mechanical interlock switch and disables operation of the vaporizer 150. When the switching mechanism 1020 is activated to operate the vaporizer 150, the interlocking mechanism enables operation of the vaporizer 150 via a mechanical interlock switch and disables operation of the humidification component 450.

[0374] Enabling and disabling each of the humidification component 450 and the one or more vaporizers 150 can be done through various suitable means, and in some embodiments, electronic and / or mechanical actuators can be used. These actuators can be operatively linked to the switches and interlocks discussed in connection with FIGS. 42-51 that enable selective operation of the humidification component 450 and at least one vaporizer 150. For example, an electronic actuator controlled by the interlocking and switching functions can vary the power supply to the humidification component 450, such as to reduce humidity to zero or low / negligible amounts. In another example, an electronic actuator controlled by the interlocking and switching functions can vary the power supply to the one or more vaporizers 150, such as to reduce the release of anesthetic agent to zero or low / negligible amounts. In another example, a mechanical actuator controlled by the interlocking and switching functions can include one or more valves, such as shutoff valves or diverter valves, that can reduce or block the flow path to or from the component. Alternatively or additionally, one or more solenoids or proportional valves may be provided downstream of or at the outlet of humidification component 450 and / or vaporizer 150 (or at the inlet of the vaporizer) to enable / disable these components by increasing or decreasing the flow rate. In other embodiments, when vaporizer 150 is disabled, the vaporizer may still form part of the flow path through which gas is delivered to the patient, although in other cases the flow path may be closed using shutoff valves, solenoids, etc., as previously described.

[0375] FIG. 54 is a schematic diagram of three gas lines supplied to a respiratory apparatus 100, which in some embodiments includes multiple flow meters 190. In FIG. 54, the respiratory apparatus 100 is supplied with a source of gas including nitric oxide (NO), oxygen (O2) and / or air, such as via flow source 1030 or gas source 1060 as shown in FIG. 38. The NO gas line includes flow meter 190A and the air gas line includes flow meter 190B to control the flow rates for mixing the gases to a desired composition for delivery of a flow of respiratory gas to the patient 300. In this embodiment, the O2 gas line includes flow meter 190C and flow meter 190D. The operation of flow meters 190C and 190D in the oxygen line is controlled by a switching mechanism 700.

[0376] When the respiratory apparatus 100 operates in a first mode, which may be an anesthesia ventilation mode (e.g., providing ventilatory assistance with or without anesthesia), the switching mechanism 700 disables operation of the O2 gas line with the flow meter 190D. In contrast, when the respiratory apparatus 100 operates in a second mode, which is ideally a high-flow respiratory assistance mode, the switching mechanism 700 disables operation of the flow meter 190C and enables operation of the flow meter 190D to deliver O2 and / or air at a constant flow rate to the patient 300. The flow rate may be in the range of about 20 L / min to about 90 L / min. The flow rate may be in the range of about 40 L / min to about 70 L / min. The flow rate may be about 20 L / min, about 40 L / min, or about 70 L / min.

[0377] FIG. 55 is another schematic diagram of three gas lines supplying the respiratory apparatus 100, including three flow meters 190A, 190B, and 190C, and including two additional flow meters 190E and 190F operable on the O2 gas line. When the respiratory apparatus 100 operates in a second mode, ideally a high-flow respiratory assistance mode, the switching mechanism 700 disables the operation of the flow meter 190C and enables the operation of one of the flow meters 190E and 190F. As shown in FIG. 55, the flow meter 190E can deliver O2 to the patient 300 at a flow rate of about 40 L / min, and the flow meter 190F can deliver O2 to the patient 300 at a flow rate of about 70 L / min.

[0378] Figures 56 and 57 show gas flow through the respiratory apparatus 100 in two modes of operation controlled by the switching mechanism 1020, as previously described. The switching mechanism 1020 may be operable in conjunction with the linkage mechanisms described in relation to Figures 41-46 to change the mode of operation of the respiratory apparatus 100. The illustrated schematic is significantly simplified from that of Figure 38, eliminating the vaporizer 150 in the inhalation flow path to the inhalation conduit 110, and eliminating components in the exhalation flow path including the rebreathing component 140.

[0379] FIG. 56 shows a first mode of operation of the respiratory apparatus 100, in which the respiratory apparatus 100 delivers breathing gas to the inhalation flow path and receives a return of exhaled gas via the exhalation flow path. The respiratory apparatus 100 receives a fresh gas flow (FGF), which is a mixture of gas (e.g., one or more of NO, O2 and air) and / or one or more anesthetic agents that supplement the gas flow via the rebreathing component 140. The gas flow is directed to the inhalation conduit 110 to deliver a flow of breathing gas to the patient's airway 310 via the first patient interface 120 (see also FIG. 38). Exhaled gas from the patient 300 is received via the exhalation conduit 130, which forms a return flow path 140 including a CO2 absorber 141 configured to treat the returned exhaled gas from the patient 300 before recirculating it to the patient 300 in the first mode.

[0380] In FIG. 57, the switching mechanism 1020 allows the respiratory apparatus 100 to operate in a second mode of operation in which the respiratory apparatus 100 delivers breathing gas to the inhalation flow path at a predetermined flow rate without return of exhaled gas from the patient 300. In the second mode, the respiratory apparatus 100 receives a fresh gas flow (FGF), which is a mixture of O2 and / or air without any anesthetic agents (volatile or non-volatile). The gas flow is directed to the humidification component 450 to condition the breathing gas flow to a predetermined humidity and / or temperature before delivery to the patient 300. The conditioned flow of breathing gas is then delivered to the patient 300 via the second patient interface 220 through the inhalation conduit 210. Alternatively, in the second mode, the conditioned flow of breathing gas may be delivered directly from the humidification chamber 450 to the inhalation conduit 210 without being returned to the respiratory apparatus 100.

[0381] In a second mode of operation, the CO2 absorber 141 may be further configured to condition the breathing gas in the inhalation flow path to a predetermined temperature and / or humidity before delivery to the patient 300. The CO2 absorber 141 in the second mode may be configured to condition the breathing gas to a predetermined temperature and / or humidity by one or both of altering the amount of soda lime present in the CO2 absorber 141 and altering the amount of CO2 provided to the soda lime present in the CO2 absorber 141.

[0382] For example, the reaction of the soda lime CO2 absorber 141 can be used to humidify the high flow rate of gas. A switch (mechanical, electronic or otherwise) can be employed in the respiratory apparatus to switch the CO2 absorber 141 between anesthesia ventilation mode and high flow mode. Additionally, the geometry of the soda lime can be adjusted to alter the level of humidification and increase humidity to a level suitable for high flow respiratory support. Additionally / alternatively, the amount of CO2 provided to the soda lime can be adjusted to increase reaction with the soda lime, thereby increasing humidity. Thus, as shown in FIG. 57, the CO2 absorber 141 can be employed in a second mode (e.g., high flow mode) of the respiratory apparatus 100 to provide additional humidification of the gas flow.

[0383] The two modes of operation shown in Figures 56 and 57 may be controlled through detection of coupling of the humidification component 450 with the mount 160. The respiratory apparatus 100 may be configured to detect coupling of the humidification component 450 with the mount 160 to enable operation of the respiratory apparatus 100 in a second mode. As shown in Figure 38, the respiratory apparatus 100 may include a sensor 1050 in communication with the controller 1010. The sensor 1050 may be configured to detect coupling of the humidification component 450 with the mount 160. The controller 1010 may be configured to process data from the sensor 1050 to identify coupling of the humidification component 450 with the vaporizer 150. The controller 1010 may then communicate with a switching mechanism 1020 to switch between modes of operation, such as between a first mode and a second mode, as shown in Figures 56 and 57.

[0384] The sensor 1050 may include electronic and / or mechanical features to detect coupling. For example, the sensor 1050 may detect a change in an electrical characteristic, such as resistance, capacitance, or inductance, in an electrical circuit when the humidification component 450 is coupled to the mount 160. Alternatively, the humidification component 450 may include a machine-readable component associated with the housing 422, such as a radio frequency identification detection (RFID) device that may be detected by the sensor 1050 when the humidification component 450 is coupled with the mount 160. In other embodiments, the respiratory apparatus may eliminate the sensor 1050 and instead provide a mechanical arrangement to detect coupling, such as via a lock and key arrangement, etc., as will be appreciated by those skilled in the art.

[0385] advantage Embodiments of the present disclosure provide a configuration that allows easy alternation between respiratory assistance via high flow and respiratory assistance with anesthesia ventilation / anesthetic agent delivery via an anesthesia machine.

[0386] Some embodiments provide a single machine that provides the functionality of both high-flow respiratory support and a rebreathing system to deliver anesthesia, which can easily transition or switch between high-flow and anesthesia machine (rebreathing) modes. Desirably, this allows a clinician to easily switch between deploying high-flow respiratory support and the rebreathing system and then inducing / ventilating the patient. This reduces the overall number of components and simplifies the work environment, making it easier for anesthesiologists to perform the tasks required during procedures involving high-flow therapy in addition to administering anesthesia.

[0387] When switching from rebreathing mode to high-flow mode, it is desirable for the transition to stop gas delivery from the anesthesia machine for safety reasons. Uncontrolled delivery of O2 outside of the rebreathing system (e.g., when the mask is removed from the patient) can create a fire hazard, there can be waste of anesthesia gas, and anesthesia gas can be unintentionally released into the surgical environment, contaminating the high-flow respiratory support gas as well as affecting the ability of the person in the surgical environment. Embodiments of the present invention address one or more of these issues.

[0388] Also described herein are various embodiments, apparatus, connectors, assemblies, accessories, devices, etc., that accomplish switching between modes of respiratory assistance. Some of these provide the convenience of controlling mode selection when the user is not at the "machine" by providing a switching actuator closer to the patient or clinician. Some embodiments provide automatic selection of operating modes by monitoring characteristics of gases in the system, such as gas pressure and CO2 concentration in exhaled gas. These features not only improve the convenience and ease of use of systems that provide these modes of respiratory assistance, but also have the potential to improve patient safety.

[0389] Humidification of respiratory gas delivered during high-flow respiratory assistance can be important because the gas would otherwise have a drying effect on the airways that can lead to damage and other complications. Embodiments of the present disclosure provide a respiratory apparatus that allows for humidification of respiratory gas delivered during high-flow respiratory assistance. The respiratory apparatus includes a mount coupleable with a humidification component that conditions the flow of respiratory gas to a predetermined temperature and / or humidity prior to delivery to the patient.

[0390] Embodiments of the respiratory apparatus may also advantageously provide an interlocking mechanism that prevents simultaneous operation of the humidification component and the vaporizer(s). This may desirably prevent delivery of volatile anesthetic agents to the patient during high-flow respiratory assistance. Additionally, the respiratory apparatus may also include a switching mechanism configured to enable selective operation of the humidification component and at least one vaporizer. The switching mechanism may be coupled with the interlocking mechanism to provide easy switching and safe transition between anesthesia ventilation and high-flow modes of the respiratory apparatus during medical procedures requiring both forms of respiratory assistance.

[0391] It should be understood that various modifications, additions and / or substitutions can be made to the elements described above without departing from the scope of the present invention as defined in the claims appended hereto.

[0392] The invention can also be broadly described as consisting in any or all combinations of two or more of the parts, elements and features referred to or shown individually or collectively in the specification of this application. Where in the above description wholes or components having known equivalents are referred to, those wholes are incorporated herein as if individually set forth.

[0393] When any or all of the terms "comprise", "comprises", "comprised" or "comprising" are used in this specification (including the claims), they should be interpreted as specifying the presence of stated features, integers, steps or components, but not as excluding the presence of one or more other features, integers, steps or components or groups thereof.

[0394] It should be understood that the following claims are provided by way of example only and are not intended to limit the scope of what may be claimed in the future. Features may be added to or omitted from the claims at a later date so as to further define or redefine the invention.

Claims

1. 1. A multi-lumen assembly for use with a respiratory assistance system, comprising: (a) a first inhalation conduit having a first conduit inlet end connectable to a first gas outlet of the respiratory assistance system; (b) a second inhalation conduit having a second conduit inlet end connectable to a second gas outlet of the respiratory assistance system; (c) an expiratory conduit having an expiratory conduit outlet end connectable to an expiratory gas inlet of the respiratory assistance system; A multi-lumen assembly having a plurality of conduits including:

2. 2. The multi-lumen assembly of claim 1, wherein the first inhalation conduit has a first conduit outlet end connectable to a first patient interface configured for sealing engagement with and directing flow into a patient's airway.

3. 3. The multi-lumen assembly of claim 1 or 2, wherein the second inhalation conduit has a second conduit outlet end connectable to a second patient interface configured to direct flow into the patient's airway, the second patient interface being a non-sealing interface.

4. The multi-lumen assembly according to any one of claims 1 to 3, wherein at least some of the plurality of conduits are arranged coaxially.

5. The multi-lumen assembly of claim 4 , wherein an outer wall of the inner lumen defines an inner wall of an adjacent lumen.

6. A multi-lumen assembly according to any preceding claim, including a mechanism for holding at least a portion of the plurality of conduits in a mass.

7. The multi-lumen assembly of claim 6 , wherein the mechanism comprises webbing disposed between at least pairs of the plurality of conduits, either spaced apart or continuously along at least a portion of the plurality of conduits.

8. The multi-lumen assembly of claim 7 , wherein the webbing is breakable to facilitate separation of at least a portion of one or more of the plurality of conduits from the mass.

9. A multi-lumen assembly according to any one of claims 6 to 8, wherein the mechanism comprises a sheath applied around the plurality of conduits.

10. A multi-lumen assembly according to any preceding claim, wherein the second inhalation conduit is configured to deliver breathing gas to a patient at a flow rate of between 20 L / min and 90 L / min.

11. A multi-lumen assembly according to any preceding claim, including a flow switching mechanism operable to direct a flow of breathing gas into the first inhalation conduit or into the second inhalation conduit.

12. The multi-lumen assembly of claim 11 , wherein the flow switching mechanism is operatively coupled to a respiratory assistance system controller.

13. 13. The multi-lumen assembly of claim 12, wherein the respiratory assistance system controller controls the respiratory assistance system to deliver respiratory gas to the multi-lumen assembly in accordance with operation of the flow switching mechanism by a user.

14. The multi-lumen assembly of claim 12 , wherein the respiratory assistance system controller controls operation of the flow switching mechanism.

15. 15. A multi-lumen assembly according to any one of claims 1 to 14, wherein the outflow end of the first inhalation conduit and the inflow end of the expiratory conduit form a common gas flow path defined by a single gas exchange conduit connectable to a first patient interface.

16. The multi-lumen assembly comprises: (a) connecting an outlet end of the first inhalation conduit to a first patient interface; (b) connecting the outlet end of the second inhalation conduit to a second patient interface. A multi-lumen assembly according to any preceding claim, including a patient end connector.

17. 17. The multi-lumen assembly of claim 16, wherein the patient-end connector includes a switching element operable to switch the patient-end connector between a first mode of operation in which the patient-end connector directs respiratory gas to the first patient interface and a second mode of operation in which the patient-end connector directs respiratory gas to the second patient interface.

18. 20. The multi-lumen assembly of claim 17, wherein the switching element is operatively connectable to a respiratory assistance system controller, the respiratory assistance system controller controlling operation of the switching element.

19. 20. The multi-lumen assembly of claim 18, wherein the switching element is operable by a user, and the respiratory assistance system controller controls operation of the respiratory assistance system in accordance with manipulation of the switching element by the user.

20. A multi-lumen assembly according to any preceding claim, further comprising a gas sampling conduit for monitoring one or more properties of the gas.

21. A multi-lumen assembly as described in claim 20, which relies on any one of claims 16 to 19, wherein the characteristic is used by a respiratory assistance system controller to determine whether the patient end connector is delivering respiratory gas to the patient in the first inhalation conduit or the second inhalation conduit, and the respiratory assistance system controller operates the respiratory assistance system to automatically select a corresponding operating mode of the respiratory assistance system.

22. A multi-lumen assembly according to any preceding claim, wherein the first inlet conduit is configured to deliver breathing gas containing an anaesthetic agent to a patient.

23. A multi-lumen assembly according to any preceding claim, wherein the expiratory conduit is configured to return exhaled gases from a patient to the respiratory assistance system.

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