Respiratory assist device

Abstract

A device for providing respiratory assistance to a patient includes a first gas flow path, a second gas flow path, and a first gas port configured to receive gas from either the first gas flow path or the second gas flow path. The device includes a switching mechanism operable to switch the flow of the first gas port between the first gas flow path and the second gas flow path. The gas from the first gas port is provided to the patient for respiratory assistance.

Description

Technical Field

[0001] The present disclosure relates to devices and systems that provide respiratory assistance to a patient and switch between modes of respiratory assistance provided to the patient. In particular, but not exclusively, it relates to an apparatus that switches between modes of respiratory assistance that provide ease of use in a clinical setting.

Background Art

[0002] A patient may lose respiratory function during anesthesia or sedation, or more generally during some medical procedures. Prior to a medical procedure, a patient may be pre-oxygenated by a medical professional to provide an oxygen saturation reservoir. Pre-oxygenation and CO2 flushing / washes may be performed with high-flow respiratory assistance via a nasal cannula or other patient interface.

[0003] There may be a high-flow system in an operating room for use during anesthetic or sedation procedures, or other medical procedures. High-flow respiratory assistance has been found to be effective in promoting a patient's oxygenation, reducing the work of breathing, and performing transnasal humidified rapid-insufflation ventilation exchange (THRIVE) by meeting or exceeding the patient's normal inspiratory demand. By performing pre-oxygenation using a high-flow system before administering an anesthetic or sedative, an oxygen reservoir is provided and the safe apnea time is extended. Furthermore, a flushing effect can be generated in the nasopharynx so that it is flushed by a high-flow gas stream that enters the anatomic dead space of the upper airway. This results in a reservoir of fresh gas available for each breath while minimizing rebreathing of carbon dioxide, nitrogen, etc. THRIVE is to provide a patient with a high-flow respiratory gas when the patient is apneic, and is performed before the anesthetic takes effect and before the patient is successfully intubated and mechanically ventilated. High-flow respiratory assistance refers to delivering heated and humidified respiratory gas to a patient via a non-airtight patient interface (such as a nasal cannula) at a high flow rate generally intended to meet or exceed the patient's inspiratory demand when the patient is breathing spontaneously.

[0004] When pre-oxygenation is performed, an anesthetic agent is delivered to the patient to sedate the patient prior to intubation. Even after intubation, an anesthetic agent is delivered to maintain the patient's anesthetic state during medical procedures. This delivery of the anesthetic agent can be performed intravenously or by inhalation of aerosol / vapor, and the latter can be achieved by using an anesthesia apparatus. A system configured for anesthetic procedures typically includes an anesthesia apparatus, and the anesthesia apparatus includes a rebreathing system in which exhaled gas from the patient is returned to the anesthesia apparatus. The anesthesia apparatus provides an anesthetic agent for sedating and / or maintaining the patient in a sedated state via a sealed mask placed over the patient. When sedated, the patient is intubated and mechanically ventilated (anesthetic ventilation) by an anesthesia apparatus that assists or replaces spontaneous breathing.

[0005] The provision of various respiratory assistance modes is rarely performed in a simple continuous manner. In the clinical setting, it is often necessary to switch the assistance mode, for example, to ensure appropriate oxygenation during anesthesia induction and intubation. Different patient interfaces may be required depending on the mode of respiratory assistance, such as non-sealed, sealed face masks, endotracheal tubes, etc., and this may require multiple gas sources and / or multiple inspiratory gas flow conduits for providing a gas flow from a respiratory assistance system. It may be desirable to simplify the clinical setting by reducing the number of tubes and / or connections (and / or connection / disconnection operations), while at the same time enabling the clinician to switch between various modes of respiratory assistance that may be appropriate for achieving a desirable clinical outcome for the patient.

[0006] Any reference in this specification to a patent document or any other matter identified as prior art shall not be construed as an admission that the document or other matter was known or that the information contained therein was part of common general knowledge. SUMMARY OF THE INVENTION MEANS FOR SOLVING THE PROBLEM

[0007] In one aspect, the present disclosure provides a device for providing respiratory assistance to a patient, the device comprising: (a) a first gas flow path; (b) a second gas flow path; (c) a first gas port configured to receive gas from either the first gas flow path or the second gas flow path; and (d) a switching mechanism operable to switch the flow to the first gas port between the first gas flow path and the second gas flow path, wherein gas from the first gas port is provided to the patient for respiratory assistance.

[0008] In some embodiments, when the switching mechanism operates to allow flow to the first gas port from one of the gas flow paths, flow to the first gas port from the other gas flow path is blocked.

[0009] In some embodiments, the first gas port is connectable to a first conduit that provides gas to the patient through a second patient interface.

[0010] In some embodiments, the device includes a second gas port that is connectable to a second conduit configured to receive exhaled gas from the patient. The device may include a first patient interface, such as a face mask, configured to receive exhaled gas from the patient and return it to the device through the second conduit.

[0011] In some embodiments, application of the first patient interface to the patient causes the switching mechanism to allow flow from the first flow path to the first gas port. In some embodiments, application of the first patient interface to the patient may be identified by detecting an increase in one or more parameters of the gas in the exhaled gas flow path between the second patient interface and the device, the parameters being selected from the group including gas pressure, CO2, O2, flow rate, temperature, humidity. In some embodiments, the first patient interface is a face mask including a sealing cuff having a sensor for identifying the pressure within the cuff, and application of the face mask to the patient is identified by an increase in cuff pressure.

[0012] In some embodiments, the first patient interface includes one or more sensors configured to identify that the second patient interface has been applied to the patient. In some embodiments, the one or more sensors of the first patient interface include one or more of an optical sensor, a proximity sensor, and a temperature sensor.

[0013] In some embodiments, the device is connectable to the first and second conduits via a Y-piece connector and includes an endotracheal tube (ETT) or a laryngeal mask airway (LMA) that functions as both the first and second patient interfaces. In some embodiments, the device may be configured to be used as a ventilator.

[0014] In some embodiments, when the first patient interface is removed from the patient, the switching mechanism enables flow from the second gas flow path to the first gas port.

[0015] In some embodiments, when gas flows from the second gas flow path to the first gas port, the device is operable to provide gas to the patient through the second patient interface, which is an unsealed patient interface such as a nasal cannula.

[0016] In some embodiments, the switching mechanism includes a switching element configured to block flow from the flow source to the other gas flow path when the switching mechanism is operative to enable flow from one of the gas flow paths to the first gas port.

[0017] In some embodiments, the switching mechanism includes one or more valves upstream of the confluence point between the first and second gas flow paths, configured to prevent backflow in the other gas flow path when the switching mechanism is operative to enable flow from one of the gas flow paths to the first gas port.

[0018] In some embodiments, the switching mechanism can be operably coupled to one or more flow meters configured to stop the gas flow to the gas flow path that does not provide the gas flow to the first gas port in response to the operation of the switching mechanism.

[0019] In some embodiments, the switching mechanism is operably coupled to one or more flow meters operable to control the gas flow to the gas flow path that provides the gas flow to the first gas port in response to the operation of the switching mechanism.

[0020] In some embodiments, the switching mechanism is operably coupled to one or more flow meters operable to control the gas flow to the gas flow path that provides the gas flow to the first gas port in response to the operation of the switching mechanism, and the one or more fixed flow meters control the gas flow to one or more preset gas flow rates.

[0021] In some embodiments, the device includes a controller that communicates operably with the switching mechanism and is operable with respect to the device to deliver respiratory assistance to a patient. In some embodiments, the controller can receive input from one or more sensors and identify whether the first patient interface has been applied to the patient.

[0022] In some embodiments, when it is identified that the first patient interface has been applied to the patient, the controller automatically controls the device to provide respiratory assistance in a first mode, and when it is identified that the first patient interface has been removed from the patient, the controller automatically controls the device to provide respiratory assistance in a second mode.

[0023] In some embodiments, the controller may receive input from one or more sensors at one or more locations selected from the group including within the breathing flow path that provides gas to the patient, between the first gas port within the device and the confluence point within the device where the returned gas meets the fresh gas supply, within the expiratory flow path that returns gas from the patient to the device, between the second gas port within the device that receives the gas returned from the patient and the confluence point, and within the gas flow downstream of the flow generator or flow mixer of the device. The one or more sensors can be of a sensor type selected from the group including, but not limited to, pressure sensors, flow sensors, and O2 sensors.

[0024] In some embodiments, the controller may receive input from one or more CO2 sensors at one or more locations selected from the group including between the second gas port within the device that receives the gas returned from the patient and the CO2 absorber within the device having an expiratory flow path that returns gas from the patient to the device, a rebreathing circuit, and a CO2 absorber. In some embodiments, the controller identifies that one or more locations where the CO2 concentration is higher than ambient air are associated with the patient interface applied to the patient.

[0025] In some embodiments, the controller may receive input from multiple sensors to identify whether the first patient interface has been applied to the patient, thereby reducing incorrect switching between the first mode and the second mode.

[0026] In some embodiments, the controller may be able to control the device to provide a signature flow element for respiratory assistance, and the controller searches for the signature flow element in the returned gas and identifies that the first patient interface is applied to the patient. The signature flow element can include, for example, variations in one or more of the frequency, amplitude, and profile of one or more of the pressure, flow rate, and O2 concentration of the gas provided to the patient.

[0027] In some embodiments, the controller may receive sensor signals from one or more sensors including one or more pressure and / or flow rate and / or gas concentration sensors in the intake flow path and / or the exhalation flow path, control the switching from the second mode to the first mode, and optionally, one or more of the same or different sensor signals may be received by the controller to control the switching from the first mode to the second mode. The controller may be configured such that more sensor conditions must be satisfied to switch from the first mode to the second mode or vice versa. This may be configurable according to the user's preference.

[0028] In some embodiments, the controller may control the device to provide a residual gas flow in one or both of the first gas flow path and the second gas flow path for continuous or regular monitoring of the gas. In some embodiments, the residual gas flow may be from about 0.5 L / min to about 5 L / min.

[0029] In some embodiments, the device may include one or more sensors that detect one or more characteristics of the gas selected from the group including pressure, flow rate, and gas species concentration.

[0030] In some embodiments, the controller may apply timing control and, when a state to trigger a mode switch is detected, the controller may apply a delay before controlling the switching element to perform the mode switch. In some embodiments, the controller may control the user interface to provide one or more of an auditory and a visual countdown indicator when the controller switches the control of the device between the first mode and the second mode. In some embodiments, the controller may be configured to abort the automatic switching between modes when a user input to cancel is received during the delay.

[0031] In some embodiments, the controller may control a user interface that provides one or both of an auditory and a visual mode display representing the current operating mode of the device. In some embodiments, the controller may position the user interface on, at, or near the gas conduit or patient interface, and the user interface may include one or more auditory and / or visual output elements that provide the mode display.

[0032] In some embodiments, the device includes a user interface that is operatively communicable with the controller and is configured to receive input from a user corresponding to one or more parameters of respiratory assistance to be provided to the patient. The parameters may include one or more parameters for a rebreathing mode of respiratory assistance and / or a high-flow mode of respiratory assistance. The parameters may include one or more of the flow rate, composition, pressure, temperature, and humidity of the gas provided to the patient.

[0033] In some embodiments, the controller may be configured to receive a user input that causes a switching mechanism to switch the flow to the first gas port between a first gas flow path and a second gas flow path. The user input may be received from one or more of (a) a touch screen display, (b) a wired or wirelessly connected remote unit, (c) a foot-operated pedal or switch, and (d) a physical switch provided on the device.

[0034] In some embodiments, the first gas flow path includes a rebreathing gas flow path that receives and processes the exhaled gas returned from the patient. Processing the exhaled gas returned from the patient may include recirculating the exhaled gas within the first gas flow path. In some embodiments, the device may be operable to provide one or both of anesthesia and ventilatory respiratory assistance via the recirculation gas flow path.

[0035] In some embodiments, the second gas flow path includes a high-flow gas flow path. In some embodiments, the device includes a flow source configured to generate a flow of gas within the second gas flow path.

[0036] In some embodiments, the first gas port is a common gas outlet port connectable to a first conduit for delivering gas from either the first gas flow path or the second gas flow path to the patient.

[0037] In some embodiments, a housing in which the first gas flow path and the second gas flow path are provided, the housing providing a first gas coupling defining the first gas port to which the first conduit is connectable.

[0038] In some embodiments, the device includes a humidifier configured to adjust the gas to a predetermined temperature and / or humidity before delivering the gas to the patient through one or both of the first and second gas flow paths.

[0039] In some embodiments, the device may be operable to provide a gas flow within the second gas flow path at a flow rate selectable from a range of available flow rates of about 20 L / min to about 100 L / min. Alternatively, the device may be operable to provide a gas flow within the second flow path at a flow rate selectable from a plurality of available fixed flow rates including at least 0 L / min, 40 L / min, and 70 L / min.

[0040] In some embodiments having a second gas port configured to receive exhaled breath from the patient, the device may include a CO2 absorber configured to process the exhaled gas returned from the patient within the first gas flow path. This may be provided before recirculating the gas to the patient within the first gas flow path.

[0041] In some embodiments, the device includes one or more of the following functions within the first gas flow path: (a) a pressure limiting valve configured to maintain a substantially stable pressure within the first gas flow path, (b) a variable volume section for replacement of the gas within the first gas flow path, (c) a replenishment gas flow for replenishing the anesthetic gas delivered to the patient within the first gas flow path, (d) a gas mixer, (e) a vaporizer for vaporizing a volatile anesthetic agent into the gas within the first gas flow path, and (f) a flow limiter configured to limit the flow rate within the first gas flow path to approximately 15 L / min.

[0042] In some embodiments, the device may include one or more gas supply ports configured to receive a supply of one or both of (a) breathing gas delivered to the patient by the first or second gas flow path, and (b) anesthetic gas delivered to the patient by the first gas flow path.

[0043] In some embodiments, the device may be configured to couple to a power source including a general-purpose power outlet or a battery.

[0044] In some embodiments having a second gas port configured to receive exhaled gas from the patient, the device may be configured to operate in (a) a rebreathing mode in which gas flows from the first gas flow path to the first gas port, is provided to the patient, and the exhaled patient gas is returned to the device via the second gas port, and (b) a high-flow mode in which gas flows from the second gas flow path to the first gas port and the exhaled patient gas is provided to the patient without being returned to the device. In some embodiments, the rebreathing mode may include an anesthetic rebreathing mode for providing anesthesia to the patient. Alternatively or additionally, the device may be configured for use in a ventilatory rebreathing mode, in which case gas flows from the first gas flow path to the first gas port, is provided to the patient via an ETT or LMA, and the exhaled patient gas is returned to the device via the second gas port. The device may be operable to provide, for example, automatic rebreathing by use of bellows of the device, or manual rebreathing by use of a manual bag-valve-mask.

[0045] Viewed from another aspect, the present disclosure provides a device for providing respiratory assistance to a patient, the device comprising a first gas flow path, a second gas flow path, a first gas port configured to receive gas from either the first gas flow path or the second gas flow path, a switching mechanism operable to switch the flow to the first gas port between the first gas flow path and the second gas flow path, wherein the gas from the first gas port is provided to the patient for respiratory assistance, the device further comprising a controller configured to receive an input from one or more sensors to identify whether there is a condition that triggers a switch between the first gas flow path and the second gas flow path for the flow to the first gas port, the one or more sensors being provided at one or more locations selected from the group consisting of within the inspiratory flow path that provides gas to the patient, within the device, between the first gas port and the confluence point where the gas returned within the device meets the fresh gas supply, within the expiratory flow path that returns gas from the patient to the device, between the second gas port that receives the gas returned from the patient within the device and the confluence point, and within the gas flow downstream of the flow generator or flow mixer of the device.

[0046] In some embodiments, the device includes a second gas port configured to receive gas returned from the patient, and the condition includes the controller identifying whether a sealed patient interface in fluid communication with the second gas port is applied to the patient or not.

[0047] Viewed from another aspect, the present disclosure provides a device for providing respiratory assistance to a patient, the device comprising a first gas flow path, a second gas flow path, a first gas port configured to receive gas from either the first gas flow path or the second gas flow path, a switching mechanism configured to switch the flow to the first gas port between the first gas flow path and the second gas flow path, wherein the gas from the first gas port is provided to the patient for respiratory assistance, the device further comprising a controller configured to control the device to provide a signature flow element for respiratory assistance, the controller searching for a signature flow element in the gas returned from the patient to the device and identifying whether the patient interface is applied to the patient or not.

[0048] In some embodiments, the signature flow element may include variations in one or more of the frequencies, amplitudes, profiles of one or more of the pressure, flow rate, and O2 concentration of the gas provided to the patient.

[0049] It should be understood that each of the various aspects described herein may incorporate one or more features, modifications, alternatives described with respect to one or more other aspects, and may appropriately include one or more features, modifications, and alternatives of any of the embodiments described below. For efficiency, these features, modifications, and alternatives are not repeatedly disclosed for each individual aspect, but those skilled in the art will recognize that such combinations of features, modifications, and alternatives disclosed for some aspects and embodiments will equally apply to other aspects and are within the scope of the present disclosure and form part of its gist.

[0050] Here, the present invention will be described in more detail with reference to the accompanying drawings in which like features are represented by like numerals. It should be understood that the illustrated embodiments are merely examples and should not be construed as limiting the scope of the invention defined in the provisional patent claims appended hereto.

Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0052] In this specification, embodiments of the present invention will be considered with reference to the drawings, which are not drawn to an exact scale and are merely intended to assist in the description of the present invention.

[0053] Components of an anesthetic device FIG. 1 is a schematic diagram showing the components of an anesthetic device 10, which can be configured to receive a gas supply unit 1060 that delivers respiratory assistance to a patient 300 via a piping connection known in the art. The gas supply unit 1060 can include one or more of anesthetic gas (e.g., nitrous oxide (NO)), oxygen (O2), and supply air. The supply air can be ambient air. A flow meter can be incorporated into the gas supply unit 1060, or placed upstream of the anesthetic device 10, or incorporated into the anesthetic device 10 to control the flow of gas through the anesthetic device. The flow meter can be manually controlled and / or precisely controlled by a controller of the anesthetic device in some cases.

[0054] The breathing circuit delivers gas to patient 300 and returns exhaled gas to the rebreathing component 140. The breathing circuit may include a corrugated tube, a valve, and one or more patient interfaces that direct gas to the patient's airway and remove exhaled gas. In the schematic of FIG. 1, the breathing circuit is shown as being simplified and including an inspiratory conduit 110 that directs gas to the airway 310 of patient 300 (but not limited to), a first patient interface 120, and an expiratory conduit 130 that collects exhaled gas. Thus, the first patient interface 120 may be a sealed interface such as a sealed mask or an endotracheal tube, and may be configured to direct exhaled gas from patient 300 toward an expiratory flow path 130 that returns the exhaled gas to the rebreathing component 140 of the anesthesia machine 10. The inspiratory conduit and the expiratory conduit may be connected to the patient interface by a Y-piece connector.

[0055] One or more vaporizers 150 convert volatile anesthetics such as isoflurane and sevoflurane from liquid to vapor and control the introduction of these drugs into the breathing circuit at precisely controlled concentrations and dosages in response to the requirements of a user, such as an anesthesiologist. The vaporizer 150 may be manually controlled and / or may be precisely controlled by a controller of the breathing apparatus in some cases. In some embodiments, the vaporizer 150 supplies the drug to the rebreathing component 140.

[0056] The anesthesia machine 10 incorporates a ventilation system that ventilates the patient 300 during induction and after administration of anesthetic agents to achieve continuous anesthesia. For example, during introduction when a volatile substance is being delivered (dashed line within the rebreathing component 140) and before the patient is intubated, the manual ventilation bag 142 can be used by the clinician. Due to the compliance of the ventilation bag 142, the patient can inhale and exhale a certain volume of gas through the sealed first patient interface 120 in the form of a face mask. Once intubated, the ventilation mode changes from manual to mechanical, and the manual ventilation bag 142 and associated pressure relief valve 143 are effectively isolated from the rebreathing component 140, and ventilation occurs via the mechanical system (dashed line within the rebreathing component 140). This may include a collapsible bellows 145 and / or an electric differential valve (controlled by the controller of the anesthesia machine 10) that controls the tidal volume and timing of respiration delivered to the patient through the sealed first patient interface 120 in the form of an endotracheal tube or a sealed face mask. The gas provided to the patient can have its pressure and / or volume controlled and / or its flow rate controlled by the mechanical system. The pressure relief valves 143, 146 provide for the release of excess gas from the rebreathing component 140 (resulting from the fresh gas flow from the vaporizer 150 and the returned exhaled patient gas) while preventing ambient air from entering the breathing circuit. After intubation, manual ventilation via the ventilation bag 142 can also be used if desired.

[0057] The rebreathing component 140 provides a gas recirculation system in which exhaled gas from the patient is processed as it flows through the circuit and then re-inhaled. This provides the advantage of recycling the oxygen and volatile substances present in the exhaled gas stream from the patient, reducing the presence of anesthetic agents in the atmosphere and reducing costs. The exhaled gas within the rebreathing component 140 is passed through a CO2 absorber 141 which can include a canister containing soda lime (or another CO2 absorbing substance). Soda lime (a mixture of NaOH and Ca(OH)2) acts as a CO2 scrubber to remove CO2 before the gas within the rebreathing component 140 re-enters the inspiratory conduit 110. Further, the gas from the pressure relief valves 143, 146 is directed via an exhaust (not shown) to an external scavenger system 144 which filters and recovers anesthetic gas from the gas stream.

[0058] As part of the anesthetic machine 10, it should be understood that additional functions can be provided, such as patient monitoring, suction, pressure gauges, regulators, and "pop-off" valves for protecting the components of the patient and the machine from high-pressure gas, as are known in the art. For simplicity, these are not included in the illustrated example.

[0059] Figure 2 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 active humidification by a humidifier 420 configured to heat and humidify the gas delivered to the patient's airway 310, often with gas from a gas supply unit 1060. The humidifier 420 is shown in Figure 2 as part of the ventilator 20, but this is not necessary. The gas from the ventilator 20 can be humidified by a humidifier provided separately from the ventilator and that humidifies the gas from the ventilator before they reach the first and second patient interfaces 120. The ventilator 20 can assist or replace the patient's own breathing by delivering respiratory gas controlled to reproduce the respiratory phases of "normal" inhalation and exhalation to the patient. The mechanical ventilator 184 can include a flow regulator and / or a blower and controls the pressure, volume, and respiratory rate of the respiratory gas delivered to the patient through an inhalation conduit 110 and delivered by a sealed first patient interface 120. The sealed first patient interface can be invasive (e.g., an endotracheal tube or a laryngeal mask airway (LMA)) or non-invasive (e.g., a sealed face mask). The exhaled gas leaves the patient via the first patient interface and an exhalation conduit 130, where it is processed, for example, by a filter 182 and released to the atmosphere. In some non-invasive ventilation systems, the exhaled gas exits through a vent or exhaust port of the patient interface 120 or the exhalation conduit, whereby the exhaled gas can exit into the atmosphere without returning to the ventilator device 20.

[0060] Components of a high-flow system FIG. 3 is a schematic diagram of components of a high-flow system 30 configured to receive gas from a gas supply unit 1060 to deliver high-flow respiratory assistance to a patient 300. The gas supply unit 1060 can be one or more of anesthetic gas (e.g., nitrous 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, and the gas flow 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 include a gas supply unit 1060 or a flow source such as a fan or blower as described below. The humidified high-flow gas flow is delivered to the patient 300 by a second intake conduit 210 and an open second patient interface 220. This can include a nasal cannula that 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 intake conduit 210 and the second patient interface 220, whereby components of the respiratory circuit upstream of the filter can be reused without the risk of contamination by exhaled gas inadvertently trapped by the second patient interface 220. In this regard, the filter 230 can also be provided at other locations within the flow path, such as between the humidifier 420 and the intake conduit 210. In some examples, the filter can be associated with the cannula of the open second patient interface 220 and / or be within the expiratory flow path 130.

[0061] In some configurations, the flow regulator 250 is configured to deliver gas to a patient through the high-flow system 30. In some embodiments, the flow regulator comprises gas generating means, such as a blower, adapted to receive gas from the external environment outside the high-flow system 30 and to propel the gas through the high-flow system 30. In some configurations, the flow regulator 250 can comprise a source of supply (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 from the one or more containers. In some configurations, the flow regulator 250 can comprise an oxygen concentrator.

[0062] As used herein, "high-flow" means any gas flow having a flow rate that is higher than normal / usual, 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 can be provided, for example, by a non-closed breathing system with substantial leakage, such as occurs at the inlet of a patient's airway. This can also be provided with humidification to improve patient comfort, compliance and safety. "High-flow" can mean any gas flow rate that is higher than some other threshold flow rate relevant to the situation. For example, when providing a gas flow to a patient at a flow rate that meets the inspiratory demand, the flow rate may be considered "high-flow" because it is higher than the nominal flow rate that might otherwise be provided. Thus, "high-flow" is situation-dependent, and what constitutes "high-flow" is determined by many factors such as the patient's health status, the type of treatment / therapy / support 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 indicative values of high-flow can be as follows.

[0063] In some configurations, the high-flow delivery of gas to a patient at a therapeutic flow rate can be at or higher than a flow rate of about 5 or 10 liters per minute (5 or 10 LPM or L / min). The therapeutic flow rate can be time-varying (e.g., fluctuating). That is, the therapeutic flow rate can have a time-varying (e.g., fluctuating) flow rate component. This time-varying flow rate can assist in respiratory assistance by providing improved oxygenation and / or CO2 clearance, and / or can reduce the risk of atelectasis, thereby potentially distributing the patient's pressure more evenly throughout the lungs.

[0064] In some configurations, high-flow delivery of gas to a 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 the various embodiments and configurations described herein, the flow rate of gas supplied by an embodiment of the disclosed system can include, but is not limited to, 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 assistance" may refer to delivering 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.

[0065] In "High Flow", the gas to be delivered is selected according to the intended use, for example, for therapy or assistance. The delivered gas can contain a certain percentage of oxygen. In some configurations, the percentage of oxygen in the delivered gas can be from about 15% to about 100%, from 20% to about 100%, or from about 30% to about 100%, or from about 40% to about 100%, or from about 50% to about 100%, or from about 60% to about 100%, or from about 70% to about 100%, or from about 80% to about 100%, or from about 90% to about 100%, or about 100%, or 100%.

[0066] (For premature infants / infants / children (with a body weight in the range of about 1 to about 30 kg)) The flow rate of "High Flow" can vary. The flow rate can be set from a minimum of about 0.5 LPM to a maximum of about 70 LPM, from about 0.4 LPM / kg to about 8 LPM / kg. For patients weighing less than 2 kg, the maximum flow rate can be set to 8 LPM. The varying flow rate can be set to 0.05 to 2 L / min / kg, a preferred range is 0.1 to 1 L / min / kg, and another preferred range is 0.2 to 0.8 L / min / kg.

[0067] High Flow can be used as a means to promote gas exchange and / or respiratory assistance through the delivery of oxygen and / or other gases and through the removal of CO2 from the patient's airway. High Flow can be particularly useful before, during, or after a medical procedure. Further advantages of a high flow gas stream include that the high flow gas increases the pressure within the patient's airway, thereby providing an open-lung assist to open the airway, trachea, lungs / alveoli, and bronchi. The opening of these structures promotes oxygenation and to some extent aids in the removal of CO2.

[0068] When the pressure increases, it can also prevent structures such as the larynx from obscuring the vocal cords during intubation. When humidified, the high flow gas stream can prevent the airway from drying out, relieve mucosal damage, and reduce the risks associated with airway dryness such as the risk of laryngeal spasm, and epistaxis, aspiration (as a result of epistaxis), and airway obstruction, swelling, and bleeding.

[0069] In this specification, the terms subject and patient are used synonymously. The subject or patient may refer to a human or animal subject or patient.

[0070] In this specification, references to numerical ranges disclosed herein (e.g., 1 to 10) are intended to incorporate references 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 to 8, 1.5 to 5.5, and 3.1 to 4.7), such that all sub-ranges of all ranges explicitly disclosed herein are thereby explicitly disclosed. These are merely examples of what is specifically intended, and all possible combinations of numerical values between the recited minimum and maximum values should be considered to be equally explicitly recited in this application.

[0071] Summary Embodiments of the present disclosure relate to a device for providing respiratory assistance to a patient that provides switching between different forms or modes of respiratory assistance provided by one device. Such a device may be desirable and / or beneficial for a clinician who may desire to switch between different forms of respiratory assistance delivered to a patient.

[0072] FIG. 4 is a schematic diagram showing the components of a device 1000 for providing respiratory assistance to a patient. The device includes a first gas flow path 1100, a second gas flow path 1200, and a first gas port 1300 configured to receive gas from either the first gas flow path or the second gas flow path. The device further includes a switching mechanism 1370 operable to switch the flow to the first gas port between the first gas flow path 1100 and the second gas flow path 1200. In an application where the first gas port 1300 is the port from which inspiratory gas is provided to the patient, the first gas port may be considered a common gas port for delivering inspiratory gas to the patient.

[0073] In some embodiments, device 1000 includes controller 1010, and the operation of switching mechanism 1370 can be triggered by the controller detecting one or more operating conditions of the device and / or by the controller receiving user input, as described below. Accordingly, in some embodiments, device 1000 includes user interface 1094, which can include, for example, a touch screen and / or a display device and / or monitoring including a keyboard and / or other input actuators (buttons, knobs, dials, etc.) that communicate operatively with controller 1010.

[0074] In this specification, the operation of switching mechanism 1370 that enables flow from one of the gas flow paths to first gas port 1300 may be referred to as “enabling” that flow path, meaning that switching allows flow to occur between the enabled flow path and first gas port 1300. In some embodiments, the operation of switching mechanism 1370 that enables flow from one of the gas flow paths to first gas port 1300 also blocks flow from the other gas flow path to the first gas port. The gas flow path from which flow to first gas port 1300 is blocked may be referred to in this specification as “disabled,” meaning that switching prevents or does not allow flow to occur between the disabled flow path and first gas port 1300.

[0075] FIG. 4 also shows one gas supply 1060 that supplies gas to first gas flow path 1100 and / or second gas flow path 1200, but it should be understood that multiple gas supplies may be provided in many embodiments. The gas supply 1060 shown in FIG. 4 is provided only by way of example and only with respect to showing that at least one gas is provided to the device to provide respiratory assistance to patient 300.

[0076] In some embodiments, the first gas port 1300 may be regarded as a gas outlet port, to which a first conduit, such as an intake conduit, may be connected to provide gas to a patient via a second patient interface, as described below. FIG. 4 also shows a second gas port 1400, which is configured to be connectable to a second conduit, such as an exhalation conduit, configured to receive exhaled gas from the patient 300 via the first patient interface. The exhaled gas received at the second gas port 1400 is returned to the first gas flow path 1100, as described below.

[0077] However, depending on the application, the direction of flow through the first gas port 1300 may change when the switch is made. For example, to provide high-flow respiratory assistance, the second gas flow path 1200 is initially enabled and the gas flow is provided to the patient via an unsealed second patient interface (e.g., a cannula). When the flow path to the first gas port 1300 is switched to enable the first gas flow path 1100, the unsealed second patient interface may receive exhaled gas from the patient and the intake flow is provided from the second gas port 1400 and delivered through a sealed first patient interface (e.g., a face mask). In this arrangement, the direction of flow external to the device 1000 is reversed, with the unsealed second patient interface and conduit 210 providing the exhalation flow path and the sealed first patient interface and conduit 130 providing the intake flow path.

[0078] The switching mechanism 1370 may be provided by one or more components or combinations of components that switch the flow paths of the device that provide gas flow to the first gas port 1300. In the embodiment shown in FIG. 4, the switching mechanism 1370 includes a switching element that operates to provide flow between the first gas flow path 1100 and the first gas port 1300. The dashed lines indicate an alternative “post-switch” operation in which the switching element provides flow between the second flow path 1200 and the first gas port 1300. The switching mechanism 1370 may include a switching element, such as a mechanical or pneumatic actuator, diverter, valve, or the like, and may be operated by a user of the device 1000 directly triggering the switching mechanism.

[0079] Although the switching mechanism 1370 is shown as one switch in FIG. 4, it should be understood that the switching mechanism may include one or more switching elements 1370A and 1370B shown in the schematic diagram of FIG. 5. Here, the first switching element 1370A is provided for the first flow path 1100, and the second switching element 1370B is provided for the second flow path 1200. The switching element may include a shut-off valve or other valve operable under the control of a controller 1010 such as an electronic controller which may be a sensor-driven automatic controller. In some embodiments, the switching elements 1370A, B may include an actuator operable by the user as described herein with respect to the actuator for the switching mechanism 1370.

[0080] The positions of the switching mechanism 1370 in FIGS. 4 and 5 are merely representative, and as will be apparent by reference to other examples provided herein, the switching mechanism may be located anywhere upstream of the junction between the first and second flow paths 1100, 1200 supplying the first gas port 1300, for example upstream of the components of the first and second gas flow paths 1100, 1200, and / or one or more switching elements provided downstream of the elements of the first and second gas flow paths 1100, 1200.

[0081] The switching mechanism (and associated switching elements) may be operated directly by the user or indirectly via a controller 1010 such as an electronic controller. Therefore, the switching mechanism 1370 may include an actuator operable by the user such that the user can manually select an operating mode, and as a result, enable or disable the gas flow path to the first gas port 1300 by the operation of the switching mechanism, and / or a sensor-driven automatic controller that operates the switching mechanism 1370 (and other components of the device) as described below. The various switching elements may be operatively connected to operate substantially simultaneously, or in response to other switching elements or actuators, or under the control of the controller 1010, which will be apparent by reference to the non-limiting examples provided herein.

[0082] In some embodiments, the first gas flow path 1100 can be configured to deliver breathing gas containing one or more anesthetics to a patient, and the second gas flow path 1200 can be configured to deliver breathing gas to the patient at a desired flow rate. Therefore, the first gas flow path 1100 can incorporate one or more components of the anesthesia device 10 (FIG. 1) and / or the ventilation system 20 (FIG. 2), and the second gas flow path 1200 can incorporate one or more components of the high-flow system 30 (FIG. 3). For simplicity, the same numbers are used throughout this disclosure to refer to such components.

[0083] In some embodiments, the operation of the switching mechanism 1370 is performed to configure the device 1000 in different operating modes to provide different forms of respiratory assistance to the patient. For example, when the switching mechanism 1370 is operated to enable the first gas flow path 1100, the device 1000 can be configured to operate in a first operating mode that includes a rebreathing mode in which exhaled gas from the patient is returned to the first gas flow path, and when the switching mechanism 1370 is operated to enable the second gas flow path 1200, the device can be configured to operate in a second operating mode that can be a flow control mode without rebreathing. The second operating mode can include a high-flow mode. In some embodiments, when the switching mechanism 1370 is operated to enable the first gas flow path 1100, the device 1000 can be configured to operate in a first mode that is an anesthesia rebreathing mode or a third mode that is a ventilation rebreathing mode, as described above with respect to FIG. 1. Therefore, references to operation in the first mode are also to be construed as referring to the third mode, which is also a rebreathing mode. The gas provided to the patient in this operating mode can have its pressure and / or volume controlled and / or its flow rate controlled. Ventilation can be triggered by the patient's movement or at a respiratory rate set by a ventilation device (e.g., an anesthesia machine).

[0084] This specification discloses various embodiments for preventing the delivery of anesthetic agents to a patient when a second flow path is enabled. However, it should be understood that as an alternative to, or in addition to, the examples provided, another approach may be employed. For example, to avoid harm caused by the release of anesthetic agents when the second gas flow path is enabled, device 1000 may disable the delivery of anesthetic agents to the patient by stopping the vaporizer or reducing its function to a non-functional level. Alternatively or additionally, device 1000 may invalidate the delivery of anesthetic agents. For example, the device may stop the vaporizer or reduce its function to a non-functional level within the first gas flow path 1100. Alternatively or additionally, the device may use a neutralizer within the first gas flow path that activates when the device is operated with the gas flow path 1200 enabled to inactivate anesthetic agents within the gas flow delivered from the first gas flow path 1100, thereby rendering any anesthetic agents that may be flowing through the system ineffective. Although wasteful, this can be an important safety measure.

[0085] When the first gas flow path 1100 is enabled, device 1000 enables the flow of gas from the first gas flow path to the first gas port 1300 for operation of the device in a first mode. From here, the first conduit 210 provides gas from the first gas port 1300 to the second patient interface 220 (which is an inspiratory patient interface), which directs the gas into the airway of patient 300. In this arrangement, the second patient interface 220 that provides gas to the patient may be a non-sealed interface such as a nasal cannula. The first patient interface, which is a sealed interface such as a face mask, is configured to direct exhaled gas from the patient to the second conduit 130, which returns the exhaled gas to the first gas flow path 1100 via the second gas port 1400. The returned exhaled gas may be processed by the rebreathing component 140 within the first gas flow path 1100 as described with respect to FIG. 1. When the first gas flow path 1100 is enabled, device 1000 also blocks the flow from the second gas flow path 1200 to the first gas port 1300, thereby "disabling" the second gas flow path.

[0086] When the second gas flow path 1200 is enabled, the device 1000 allows gas to flow from the second gas flow path to the first gas port 1300. Additionally, the device 1000 blocks the flow of gas from the first gas flow path 1100 to the first gas port 1300. Therefore, the first gas flow path 1100 is "disabled" to prevent the delivery of NO and anesthetic gas that may include vaporized anesthetic to the patient 300. The first conduit 210 supplies gas from the first gas port 1300 to the second patient interface 220 (which is an inspiratory patient interface), and it directs the gas into the airway of the patient 300. In this arrangement, the second patient interface 120 is a non-closed interface such as a nasal cannula having one or more nasal prongs that direct gas to one or both nostrils of the patient. When the second gas flow path is enabled and the device is configured to operate in the second mode, there is no need for the first patient interface or the second conduit to return exhaled gas to the device.

[0087] The device 1000 may be configured to receive a supply of gas including NO, O2, and / or air from the gas supply unit 1060. One or more flow meters may be provided to control the flow rate of gas within the device 1000 to achieve a desired respiratory assistance. One or more gas mixing elements may also be provided to combine the gases. The control of the flow meters may be achieved by direct control by the user (e.g., actuating an actuator such as a rotary or linear switch that directly changes the flow in the flow meter), or by the user providing an input to a controller 1010 configured to provide precise control over, for example, an electronically controlled flow meter within the device 1000.

[0088] The flowmeter can be incorporated into the gas supply unit 1060 or installed downstream of the gas supply unit to control the ratio of the gas entering the first gas flow path 1100 and the second gas flow path 1200. Alternatively, the flowmeter can be provided within the device 1000 (see FIGS. 6 and 7). Such a flowmeter can be manually controlled, for example, by a proportional valve having a rotary actuator, or can be controlled by the controller 1010 of the device 1000. To limit the gas flow rate and ratio within safe limits, for example, to ensure that the gas flow rate exiting the first gas flow path 1100 does not exceed 15 L / min in some embodiments and / or that the FiO2 does not fall below 0.21, safety functions can be built.

[0089] In some embodiments, the device 1000 can include a humidifier 420 (FIGS. 4A - 7) configured to adjust the gas to a predetermined temperature and / or humidity before being delivered to the patient. Preferably, such conditioned gas is provided within the second gas flow path 1200, although it is also envisioned that the humidifier 420 can be configured to adjust the gas to a predetermined temperature and / or humidity before being delivered to the patient via the first gas flow path 1100 when used in the ventilatory rebreathing mode. By providing the humidifier 420 within the device 1000, the advantage is obtained that the setup of the humidifier can be rationalized by incorporating it into the daily routine of setting up the device 1000 to provide respiratory assistance to the patient. However, the humidifier 420 need not be provided within the device 1000. In some embodiments, the device 1000 can be configured to cooperate with a humidifier 420 that is another component or device as shown in FIGS. 7 and 8. Similar modifications can be made to the embodiments of FIGS. 5 - 7 to provide the humidifier 420 external to the device, but for simplicity, these are not shown separately in the figures.

[0090] In FIGS. 7 and 8, device 1000 includes a housing shown by solid line 1050, in which elements of a first gas flow path 1100 and a second gas flow path 1200 as shown in FIG. 6 are stored. However, humidifier 420 is shown outside the device housing and represents another component or device. A third gas port 1210 is provided downstream of flow source 250 and is configured to enable a fluid connection between a first section 1200A of the second gas flow path and a third conduit 240 that supplies gas to humidifier 420.

[0091] In the arrangement of FIG. 7, the humidified gas is returned to device 1000 via a fourth gas port 1220 configured to enable a fluid connection between a fourth conduit 260 that houses the humidified gas from humidifier 420 and a second section 1200B of the second gas flow path. In the arrangement of FIG. 8, fourth conduit 260 is not connected to a gas port inside device 1000. Instead, the humidified gas in fourth conduit 260 flows into first conduit 210 via a junction or connector 600 such as a T-piece connector. Connector 600 may form part of or be incorporated in a first gas port 1300 or may be provided downstream of the first gas port as shown in FIG. 8. Note that in the arrangement of FIG. 8, check valve 149A may be positioned upstream of humidifier 420 within device housing 1050. Installing check valve 149A upstream with respect to humidifier 420 is also possible in FIG. 7 and in embodiments where the humidifier is provided within device housing 1050. Check valves 149A, 149B may be provided to prevent backflow in a disabled flow path as described below.

[0092] The humidifier 420 can be directly controlled by the user by providing manual input to a control interface provided separately from or on top of the device 1000, along with or on the humidifier when provided separately from the device. Alternatively / additionally, an external humidifier can be operatively coupled to the device's controller 1010, whereby the operation of the device 1000 controls the performance of the humidifier 420 when provided as part of the device or as another component external to the device. Therefore, when the switching mechanism is operated to enable the second gas flow path, the controller 1010 can increase the temperature and humidity of the gas flowing in the second gas flow path 1200 to a preset target value. The target temperature and humidity can be programmed into the controller or selected by the user through the user interface 1094. In this sense, the controller 1010 can be regarded as a master controller that operates to control all elements of the respiratory assistance provided to the patient.

[0093] When the switching mechanism is operated to switch the flow to the first gas port 1300 from the second gas flow path 1200 to the first gas flow path 1100, the controller can put the humidifier 420 into standby mode, during which time the temperature is lowered below the target temperature, but the humidifier is not completely stopped. This can improve performance by allowing the humidified gas to reach the target temperature and humidity more quickly when the control is switched back to enable the second gas flow path. However, shutting down the operation can also be considered as a control executable during the operation of the device when the first gas flow path is enabled (and the second gas flow path is disabled).

[0094] Figures 6-8 are schematic diagrams of a device 1000 in which a switching mechanism is positioned between a gas source 1060 and first and second gas flow paths 1100, 1200. The switching mechanism includes a first switching element 710 operable to direct the flow of O2 to the first gas flow path 1100 (which also receives a supply of air and NO) for operation of the device in a first mode, and to the second gas flow path 1200 for operation of the device in a second mode. Figures 6-8 provide schematic diagrams showing the operation of such a switching mechanism to enable the first gas flow path 1100 for operating the device 1000 in the first mode. In particular, in the first mode of operation, the second switching element may also be operable, in a preferred embodiment, such that the first gas flow path 1100 can operate in either a manual (147) or automatic / mechanical (148) ventilation / rebreather mode. In the embodiment shown in Figures 6-8, the manual first mode is selected. In some embodiments, the switching mechanism may also include one or more switching elements (not shown) operable to control the flow of air and / or NO to the first gas flow path 1100.

[0095] The second switching element 720 may respond to the first switching element 710. Thus, when the first switching element 710 is switched to enable the second gas flow path 1200 for operation of the device in the second mode, O2 is directed to the second gas flow path 1200 (represented by flow regulator 250 and humidifier 420), and the second switching element 720 moves to its lowest position 722 to turn off both manual and automatic ventilation / rebreather and prevent the exhaled gas returning from the patient to the second gas port 1400 from entering the rebreather component 140 of the first gas flow path 1100 and then flowing to the first gas port 1300. When the first switching element 710 is switched to enable the second gas flow path, O2 is directed to the second gas flow path 1200. In the example of Figure 8, the gas from the second flow path 1200 enters the intake conduit 210 downstream of the first gas port 1300. Thus, the operation of the first switching element 710 to enable the second gas flow path 1200 prevents O2 from entering the gas mixing element 1042 of the first gas flow path 1100 and, at the same time, also prevents the flow of fresh gas to the patient 300 through the first gas outlet 1300.

[0096] In addition to the switching mechanism that may include the switching elements 710 / 730 of FIGS. 6-9, the device 1000 may include one or more check valves or other one-way valves that prevent or control backflow within the system, for example, from a "disabled" gas flow path to the first gas port 1300. In the example shown in FIGS. 6-9, when the switching mechanism is operated to switch the gas to the first gas port 1400 from the first gas flow path 1100 to the second gas flow path 1200, the check valve 149B prevents backflow from the first gas port to the first gas flow path. Conversely, when the switching mechanism is operated to switch the flow to the first gas port 1300 from the second gas flow path 1200 to the first gas flow path 1100, the check valve 149A prevents backflow from the first gas port 1400 to the second gas flow path 1200. Additional check valves may be implemented at any location in the flow path of the device 1000, as is common in gas flow systems, particularly in rebreathing circuits.

[0097] In some embodiments, including those related to the foregoing example, the desired flow rate of the gas delivered from the second gas flow path 1200 to the first gas port 1300 can be selected by the user through the user interface 1094 of the controller 1010 or by manually operating a component of the switching mechanism or a flow controller of the device, and can be selectable from a range of about 20 LPM to about 100 LPM. However, in some cases, such as for pediatric or neonatal patients, a lower range may be desirable. In some embodiments, the desired flow rate can be selectable by the user from a plurality of available flow rates, such as 0 LPM, 40 LPM, 70 LPM, etc., but it should be understood that additional and / or different flow rates can be selectable within the high flow rate ranges disclosed herein.

[0098] The selection of the desired flow rate includes, in some embodiments, a flow rate selector in the form of, for example, a knob, a slide switch, a touch screen, or other actuator that allows the user to select the desired flow rate from a plurality of available flow rates or ranges thereof.

[0099] In some embodiments, the flow selector may include a flow switching element 730, as schematically shown in FIG. 9. In some examples, the flow switching element 730 can replace the first switching element 710, but in some embodiments, it may be desirable to provide the flow switching element 730 in addition to the first switching element 710 to avoid the problem of delay in the increase of gas flow rate when the second gas flow path 1200 is enabled. Preferably, the flow switching element 730 is operatively coupled to the second switching element 720, whereby the operation of the flow selector 730 that enables flow to the first gas port 1300 within the second gas flow path 1200 (including that through the humidifier 420 as shown in the figure) also prevents the exhaled gas returned from the patient to the second gas port 1400 from entering the rebreathing component 140 of the first gas flow path 1100 and then flowing to the first gas port 1300.

[0100] In the arrangement configuration of FIG. 9, the switching element 730 controls the flow of O2 to the first and second gas flow paths 1100, 1200. Therefore, when the flow rate switching element 730 is operated to select one of two predetermined flow rates associated with the flow rate controller 250A (for example, corresponding to 40 LPM) or the flow rate controller 250B (for example, corresponding to 70 LPM), O2 flows into the second gas flow path 1200, and the device 1000 is configured to operate in the second mode. Also, when the flow rate switching element 730 is operated to select the uppermost position shown in the figure, the flow from the O2 supply unit is directed to the first gas flow path 1100, and the device is configured to operate in the first mode. The flow rate switching element 730 and the second switching element 720 can be operatively connected. Thereby, the operation of the flow rate selector 730 that enables the second gas flow path 1200 activates the switching to the lowermost position 722 of the switching element 720, preventing the exhaled gas returned from the patient to the second gas port 1400 from entering the rebreathing component 140 of the first gas flow path 1100 and then flowing to the first gas port 1300. The operation of the flow rate switching element 730 that enables the second gas flow path 1200 blocks the entry of O2 into the gas mixing element 1042 of the first gas flow path 1100, so there is also no flow of fresh gas from the first gas flow path 1100 to the patient through the first gas port 1300. In some embodiments, the operation of the switching element 730 can also stop the supply of NO / air to the second gas flow path 1200. This can be achieved, for example, by one or more operatively connected shut-off valves provided in the NO and / or air gas flow paths. In some embodiments, the switching mechanism can also include one or more switching elements (not shown) operable to control the flow of air and / or NO to the first and / or second gas flow paths 1100, 1200.

[0101] In some embodiments, the switching mechanism may include one or more flow selectors / flow meters 190A, 190B, 190C, as shown in the schematic diagram of FIG. 10. In this example, one set of the flow meters 190A, 190B, 190C is provided to control the flow of each of O2, air, and NO to a common gas mixing element 1042, from which both the first gas flow path 1100 and the second gas flow path 1200 receive gas. In this arrangement, there is an operative connection between the flow meters 190A, 190B, 190C and the switching mechanism including the switching element 710, as indicated by the dashed lines. As described above, the switching element 710 is operable to switch the flow of gas to the first gas outlet 1300 between the first gas flow path 1100 and the second gas flow path 1200. In the arrangement of FIG. 10, when the switching element 710 is operated to enable the first gas flow path 1100 (as in the configuration of the figure), the operative connection between the switching element 710 and the flow meters 190A, 190B, 190C causes the flow meters to operate to deliver gas at a flow rate suitable for realizing respiratory assistance in the first operation mode. Conversely, when the switching element 710 is operated to enable the second gas flow path 1200, the operative connection between the switching element 710 and the flow meters 190A, 190B, 190C causes the flow meters to operate to deliver gas at a flow rate suitable for realizing respiratory assistance in the second operation mode. The required flow rate for each of the flow meters 190A, 190B, 190C can be preset for operation in a specific operation mode. For example, when the first gas flow path 1100 is enabled, the flow meters 190A, 190B, 190C may be configured to deliver a flow rate (e.g., 15 L / min at the first gas outlet 1300) for the mixed gas suitable for providing respiratory assistance in the first operation mode. When the second gas flow path 1200 is enabled, the flow meters 190A, 190B, 190C may be configured to deliver a flow rate (e.g., 40 L / min or 70 L / min at the first gas outlet 1300) for the mixed gas suitable for providing respiratory assistance in the second operation mode. The flow rate provided by the flow meters 190A, 190B, 190C can be specified according to the desired O2 and / or NO concentration.For example, to achieve an O2 concentration of 100% at a flow rate of 15 L / min, flow meter 190A can be set to 15 L / min and the flow through flow meters 190B and 190C is zero. Alternatively or additionally, the NO source can be disabled as an additional safety mechanism if the flow of NO needs to be zero, for example when providing respiratory assistance in the second operating mode. To achieve an O2:air ratio of 50:50 in the mixed gas at 15 L / min, each of flow meters 190A and 190B can be set to provide 7.5 L / min. The flow from flow meter 190C can be adjusted according to the proportion of NO required in the mixed gas flow to the patient according to the clinician's decision, and the flow from one or both of flow meters 190A and B is adjusted accordingly according to clinical needs. Alternatively or additionally, flow meters 190A, 190B, and 190C can be adjustable manually through their operation or, in an arrangement where the flow meters are operatively communicating with controller 1010, via user interface 1094.

[0102] FIG. 11 provides a variant of the embodiment of FIG. 10, which provides separate sets of flow meters 190A, 190B, 190C and 190D, 190E, 190F and separate gas mixing elements 1042A, 1042B. The first set of flow meters 190A, 190B, 190C controls the flow of each of O2, air, and NO to a first gas mixing element 1042A from which a first gas flow path 1100 receives gas. The second set of flow meters 190D, 190E, 190F controls the flow of each of O2, air, and NO to a second gas mixing element 1042B from which a second gas flow path 1200 receives gas. FIG. 11 shows separate gas sources 1060A and 1060B, but this is for ease of representation of the flows in the figure. In the illustrated embodiment, it should be understood that separate gas sources 1060A and 1060B are not required to supply each of the first and second gas flow paths 1100 and 1200. It is contemplated and noted that each of the first and second gas flow paths 1100 and 1200 can receive gas from one source of each of one or more gases provided to the patient into the respective sets of flow meters. If the first and second gas flow paths 1100 and 1200 receive gas from a single source, it should be understood that in some embodiments, NO may not be supplied to the second gas flow path 1200. Further, although a vaporizer 150 is shown downstream of the gas mixing element 1042A, it should be understood that the positions of these elements can be reversed, including configurations where the first and second gas flow paths 1100 and 1200 receive gas from a single source.

[0103] In FIG. 11, there is an operative connection, as indicated by the dashed line, between each of the flow meters 190A, 190B, 190C of the first set and the flow meters 190D, 190E, 190F of the second set and a switching mechanism including a switching element 710. As described above, the switching element 710 is operable to switch the gas flow to the first gas outlet 1300 between the first gas flow path 1100 and the second gas flow path 1200. In the arrangement of FIG. 11, when the switching element 710 is operated to enable the first gas flow path 1100 (as in the configuration of the figure), due to the operative connection between the switching element 710 and the flow meters, the flow meters 190A, 190B, 190C of the first set operate to deliver gas at a flow rate suitable for realizing respiratory assistance in the first operation mode, and block the flow from the flow meters 190D, 190E, 190F of the second set. Conversely, when the switching element 710 is operated to enable the second gas flow path 1200, due to the operative connection between the switching element 710 and the flow meters, the flow meters 190D, 190E, 190F of the second set operate to deliver gas at a flow rate suitable for realizing respiratory assistance in the second operation mode, and block the flow from the flow meters 190A, 190B, 190C of the first set. The required flow rate for each flow meter can be preset for the operation of supplying the designated gas flow path, similar to the description in FIG. 10. For example, when the first gas flow path 1100 is enabled, the flow meters 190A, 190B, 190C can be configured to deliver a flow rate for the mixed gas suitable for providing respiratory assistance in the first operation mode (e.g., 15 L / min at the first gas outlet 1300). When the second gas flow path 1200 is enabled, the flow meters 190D, 190E, 190F can be configured to deliver a flow rate for the mixed gas suitable for providing respiratory assistance in the second operation mode (e.g., 40 L / min or 70 L / min at the first gas outlet 1300). In some embodiments, when the second gas flow path 1200 is enabled, the gas flow meter can be configured such that only the O2 gas flow meter 190D provides a gas flow to the gas mixing element 1042B, and the air and NO flow meters 190E, 190F are disabled or do not provide a flow. In other cases, it may be desirable for one or both of the gas flow meters 190DE, 190E to provide a flow to the gas mixing element 1042B.Alternatively / Further, the flow meters 190A, 190B, 190C, 190D, 190E, 190F may be adjustable manually or via the user interface 1094 in an arrangement where the flow meters communicate operatively with the controller 1010.

[0104] The examples of FIGS. 6 and 7 provide the switching element 710 as part of the switching mechanism of the device 1000. The switching element 710 may include an actuator, a knob switch, or an input interface 1094 that can be operated by a user to select an operating mode. Alternatively / Further, the switching mechanism may include the operation of the controller 1010 of the device 1000 that switches the operating mode in response to a change in the operating state determined by a sensor that provides an input to the controller (e.g., application of a sealed patient interface to the patient or removal thereof from the patient).

[0105] Advantageously, in the embodiments of FIGS. 4 - 7, there is no need to set up an additional oxygen supply source, because both the first gas flow path 1100 that enables the operation of the device in the first operating mode and the second gas flow path 1200 that enables the operation of the device in the second operating mode can receive oxygen from a common gas supply source 1060. Further, in this arrangement, it is easy to switch both the first gas flow path 1100 and the second gas flow path 1200 simultaneously, such that when the second mode is selected, the first gas flow path 1100 stops delivering gas to the patient 300. This prevents the delivery of NO and anesthetic agents including volatile anesthetics vaporized in the first gas flow path 1100 in the gas flow to the first gas port, enhancing safety. Further, the anesthetic agents cannot enter the environment, inhalation of these anesthetic agents by caregivers attending to the patient is avoided, and at the same time waste is reduced.

[0106] In some embodiments that include the controller 1010 and the user interface 1094, the device may provide an auditory, visual, or tactile prompt, etc., to prompt the user about when to switch to enable the second gas flow path 1200, and prompt the user to continue using the first patient interface 120 until the amount of anesthetic in the exhaled gas returned to the device at the second gas port 1400 becomes extremely small or zero. Such a warning provides a safety function to reduce or eliminate the risk of anesthetic leakage into the medical environment. Alternatively / Additionally, the controller 1010 may be configured to provide a prompt (e.g., a second prompt) to inform the user that the first patient interface can be safely removed from the patient. The controller 1010 has a timer and may be configured to provide a second prompt that the amount of anesthetic in the exhaled gas returned to the patient becomes extremely small or zero after a sufficient time has elapsed after the switch. In some examples, the user interface 1094 provides a visual and / or auditory countdown timer that provides a guide to the user about when the elapsed time ends, indicating that the amount of anesthetic in the exhaled gas becomes extremely small or zero and it may be okay to remove the first patient interface 120. Alternatively or additionally, the device 1000 may include one or more sensors in the exhaled gas flow path for detecting the presence of anesthetic gas, and the controller 1010 may be configured to provide the second prompt only when the sensor indicates that no anesthetic gas is detected or the amount of detected anesthetic gas is less than a predetermined safety threshold.

[0107] Make the electronically usable switching element 710 physically attachable to one or both of the first or second patient interfaces 120, 220, so that when the patient interface is exchanged, for example, when moving from before intubation to intubation, or when disconnecting the patient from sedation, rapid switching between gas flow paths for the operation of the device 1000 in different modes can be enabled. For example, the switching element 710 may include a button or an electronic switch positioned on the patient interface, which can be activated to cause the device 1000 to switch to an operating mode of safely delivering gas to the patient through that interface. Alternatively, a foot pedal or a foot-operated switch or voice control may be utilized. Each of these has the potential to improve the feasibility of gas flow path / mode selection while the user is away from the control unit on the device itself.

[0108] In some embodiments of the present disclosure, the switching of the enabled gas flow paths (and operating modes) of the device 1000 is performed based on manual input by the user to the switching element or through the user interface. However, in some embodiments, the device 1000 includes a controller 1010 that receives input from one or more sensors configured to detect an operating state of the device, such as whether the first patient interface 120 is applied to the patient and receiving exhaled gas. This is because it is used only when the first gas flow path 1100 is enabled. Therefore, when the first patient interface 120 is applied to the patient, the controller 1010 ensures that the first gas flow path 1100 is enabled and the device is configured to operate in a first mode (anesthesia rebreathing) that can be considered as a "rebreathing" mode in general or a third mode (ventilation rebreathing) that can be considered as a specific example of the first mode. Conversely, when the sensor detects that the first patient interface 120 is not applied to the patient, the controller 1010 ensures that the second gas flow path 1200 is enabled and the device is configured to operate in a second mode of delivering nasal high-flow (NHF) respiratory assistance.

[0109] Various different methods or combinations of methods for detection can be used as means for providing a gas flow path and / or mode switching in a device 1000 that delivers gas to a patient. In one example, the pressure within the mask cavity is monitored by a pressure sensor and can be used to detect that the mask is applied to the patient. Detection of the mask applied to the patient can be achieved by detecting that the mask pressure has risen from the pressure expected during delivery of high-flow respiratory assistance (which is consistent with the mask being attached on the cannula), whereby the switching mechanism disables the second gas flow path 1200 and enables the first flow path 1100, and the configuration of the device is switched from the second operation (high-flow) mode to the first (rebreathing) mode. Further, or alternatively, an optical sensor can be provided within the mask, which can be configured to monitor changes in emitted / detected light that occur when the patient's skin is present and can be used to detect the placement of the mask on the patient. In some embodiments, this can be used in conjunction with a pressure sensor (e.g., detecting an increase in pressure within the cuff of the mask or within the mask cavity), which detects the increase in pressure when the mask is applied to the patient, whereby the switching mechanism disables the second flow path and enables the first flow path, and a switch from the second mode of operation to the first mode is made. In some embodiments, the pressure sensor within the cuff of the mask can be used independently of the optical sensor. Similarly, if the opposite change in these measurements is detected, this can be consistent with the mask being removed from the patient, whereby the switching mechanism disables the first flow path and enables the second flow path, and a switch from the first mode of operation to the second mode is made. Further, or alternatively, one or more pressure sensors can be provided on the outer surface of the nasal cannula. For example, a certain pressure sensor can be provided in the region of the cannula where the mask cuff is attached to a part thereof for operation of the device in the first mode and / or in the region of the cannula that is positioned inside the sealed face mask when attached to the patient. An increase in cannula pressure indicates that the mask is attached to the cannula, whereby the switching mechanism disables the second flow path 1200 for operation in the first (rebreathing) mode and enables the first flow path 1100.

[0110] Alternatively or additionally, the sensor may include a pressure sensor arranged to measure the pressure of one or both of the first gas flow path 1100 and the second gas flow path 1200. The device 1000 may provide an intermittent or discontinuous flow of gas through the first gas flow path 1100 and / or the second gas flow path 1200 to enable measurement of the pressure within the device. In some embodiments, this intermittent or discontinuous gas flow includes a flow rate, pressure, and / or volume that is less than the gas flow provided to the patient in the first and / or second modes. The difference in the resistance values to the flow is associated with the first (sealed) patient interface 120 and the second (unsealed) patient interface 220 when connected to the patient 300, which are used in the first and second modes respectively. When the measured pressure indicates that exhaled air has been returned from the patient by a sealed patient interface that is substantially sealed against the patient, the controller 1010 enables the second gas flow path 1100 in the switching mechanism and operates the device in the first mode in which a gas that may contain anesthetic is delivered to the patient 300, and the exhaled gas is returned to the rebreathing component 140 of the first gas flow path 1100. Alternatively, when the measured pressure indicates that the breathing gas is delivered to the patient by an unsealed patient interface (i.e., there is no mask to return the exhaled gas), the controller 1010 enables the second gas flow path in the switching mechanism and operates the device 1000 in the second mode in which a gas that does not contain anesthetic is delivered to the patient at a desired (high flow) rate. In some embodiments, the pressure sensor may be positioned downstream of the flow regulator 250 of the device 1000 or at any convenient location between the patient's airway in the gas flow path and the flow regulator 250.

[0111] Alternatively or additionally, one or more sensors may include a CO2 sensor associated with an inspiratory gas flow path (e.g., in one or more of the first gas port 1300, the first conduit 210, the first patient interface 120, and / or the second patient interface 220, depending on the interface configuration) and / or an expiratory gas flow path (e.g., in one or more of the second gas port 1400, the second conduit 130, and the first patient interface 120). In such an embodiment, the controller 1010 identifies that a gas flow path containing a higher concentration of CO2 than ambient air is associated with a patient interface connected to the patient's airway. If the CO2 concentration in both flow paths is higher than ambient air, the controller determines that the flow path with the higher CO2 concentration is associated with the patient interface receiving the expiratory gas, and thus identifies that it is connected to the patient's airway, enabling the first gas flow path 1100 in the device 1000, whereby the device operates in the first (or third) mode and the second gas flow path 1200 is disabled.

[0112] Alternatively or additionally, one or more sensors may include an O2 sensor that measures a characteristic (e.g., gas concentration) of O2 in the expiratory flow path. Knowing the characteristics of the O2 supplied to the patient during respiratory assistance, the controller 1010 compares the detected O2 characteristics with the supplied O2 characteristics and can identify that the first patient interface 120 is attached to the patient when it is equal to, close to, or within the range of the supplied value. Alternatively, if the detected O2 characteristic (e.g., concentration) is higher than the O2 concentration in the atmosphere (e.g., higher than 22% or higher than 25%), the controller 1010 can identify that the first patient interface is attached to the patient. Alternatively or additionally, a trace gas (e.g., nitrous oxide or other inert gas) or a flow pattern of the trace gas (e.g., including a flow rate or pressure fluctuation of a known frequency or behavior) may be provided in the first conduit 210 in addition to respiratory assistance. If the controller identifies that the trace gas or the flow pattern of the trace gas is present in the expiratory gas, it can be identified that the first patient interface is applied to the patient.

[0113] Alternatively or additionally, detection within the expiratory flow path can be utilized to identify that the first patient interface 120 (e.g., a sealed mask) has been applied to the patient and trigger a switch to the first (rebreathing) mode. One or more parameters in the expiratory flow path, such as flow rate, pressure, temperature, or humidity, can be identified using a suitable sensor. An increase in one or more of these parameters (e.g., when the sensor identifies that the temperature within the expiratory flow path has increased or is higher than the ambient temperature) indicates that the mask has been applied to the patient, triggers a switch to enable the first gas flow path, and configures the device 1000 to operate in the first (or third) mode.

[0114] FIG. 12 is a schematic diagram showing two exemplary positions S1 and S2 for sensors that detect characteristics of the gas in the intake flow path 210 and the exhalation flow path 130, respectively. The sensors can be provided at one or both of the positions S1, S2 to identify, for example, whether the first patient interface 120 is applied to the patient. The sensors at S1 and / or S2 can detect characteristics of the gas, such as, but not limited to, pressure, flow rate, and gas species concentration (e.g., O2, CO2 concentration). These sensors can be main stream sensors (where the sensing component is disposed within the intake or exhalation gas flow path) or side stream sensors that receive a sample gas withdrawn from the intake or exhalation gas flow path. Each of the positions S1, S2 can be without sensors or can include one or more sensors, and the type of sensor can be selected according to one or more characteristics of the gas to be detected. The position S1 between the confluence point 145 of the flow path connecting the rebreathing component 140 within the intake flow path 210 and / or within the device 1000 and the gas outlet port 1300 can be advantageous for sensor-driven identification of the enabled flow path because one sensor at S1 can be used to measure the flows in both the first gas flow path 1100 and the second gas flow path 1200. The gas pressure sensor at S1 can be used to identify whether the first patient interface is applied to the patient, because the pressure measured at S1 can be compared with an expected pressure value corresponding to the mode of respiratory assistance provided. In one example, the first mode can be a rebreathing mode when the first (sealed) patient interface is applied to the patient, and the second mode can be a high flow mode when the first patient interface is not applied to the patient.

[0115] Alternatively or additionally, a sensor may be provided at S2 to identify characteristics of the exhaled gas within the exhalation conduit 130. The sensor provided at S2 may be used to identify whether the first (sealed) patient interface 120 has been applied to the patient. In one example, when the device is operating in the second mode, detection of gas flow at S2 may be used to trigger a switch to the first (rebreathing) mode of operation. Conversely, when the device is operating in the first mode, detection of no gas flow at S2 may be used to trigger a switch to the second mode of operation. By optionally using multiple sensors at both sensor positions S1 and S2, redundancy in sensor-driven automatic switching between the operating modes of the device is provided. Thereby, for example, spurious triggering of mode switching that may result from room ventilation or other sources of flow can be reduced. Additionally, when multiple sensors provide an input to the controller 1010 to identify when a mode switch should be made, the safe operation of the device is not compromised by inaccurate performance or failure of only one sensor.

[0116] It should be understood that the sensor positions S1 and S2 in FIG. 12 are merely exemplary. A flow sensor for detecting flow within the second gas flow path 1200 may be positioned anywhere downstream of the flow regulator 250 or the flow meter 190. For detecting flow in the first mode of operation, the flow sensor may be positioned anywhere downstream of the gas mixer 1042. For detecting flow in any mode of operation, the flow sensor may be positioned anywhere downstream of the check valves 149A, B and / or anywhere downstream of the first gas port 1300. Alternatively or additionally, a flow sensor for detecting flow within the exhalation flow path 130 may be positioned anywhere within the flow path between the patient 300 and the junction 145. This may include positions between the patient 300 and the second gas port 1400 and / or within the device 1000, between the second gas port 1400 and the junction 145 and / or between the second gas port 1400 and the check valve 149C. A pressure sensor may be positioned at the same location as, in addition to, or instead of the flow sensor.

[0117] The O2 sensor that detects the O2 concentration in the intake air passage 210 can be positioned at any location downstream of the flow source 1060 in any operating mode, including downstream of the check valves 149A, B and / or downstream of the first gas port 1300. Alternatively or additionally, the O2 sensor that detects the O2 concentration in the exhalation air passage 130 can be positioned at any location between the patient 300 and the confluence point 145 in the passage. This can include the position between the patient 300 and the second gas port 1400 and / or the position between the second gas port 1400 and the confluence point 145 and / or between the second gas port 1400 and the check valve 149C inside the device 1000. The CO2 sensor that detects the flow in the exhalation air passage 130 can be provided at any location in the passage between the patient 300 and, if provided, the CO2 absorber 141. This can include the position between the patient 300 and the second gas port 1400 and / or the position between the second gas port 1400 and the check valve 149C and / or between the check valve 149C and the CO2 absorber 141 inside the device 1000.

[0118] In some examples, it may be advantageous to position the sensor on the device side of the first and / or second gas ports 1300, 1400 to avoid the sensor being incorporated into the disposable / consumable components of the system, thereby reducing costs. However, in some examples, it may be advantageous to detect the characteristics of the gas closer to the patient, for example, within the patient interface or in a conduit connected to the patient interface, to increase accuracy and reduce misreadings (and the possibility of mode switching) resulting from accidental crushing of the conduit and other movements that can affect the sensor's measurements.

[0119] Sensor-driven automatic switching between gas flow paths for the operation of device 1000 in different modes can be achieved by the controller 1010 receiving sensor inputs and, based on these inputs, controlling the operation of the switching element of the device when certain pre-defined conditions are met. In one example, one or more sensors capable of detecting one or more of pressure, flow rate, and gas concentration within the exhalation flow path 130 provide inputs to the controller 1010. When the flow rate or pressure or gas concentration meets a predetermined condition, for example, is higher than a predetermined threshold, for example, the flow rate is greater than 0, for example, is between about 0.5 and about 2 L / min, and / or the pressure is higher than ambient air, and / or the CO2 concentration is higher than ambient air (when the patient is breathing), and / or the O2 concentration is higher than ambient air (when the O2 provided to the patient exceeds 21%), the controller determines that the sealed mask is applied to the patient and the system is operable in the first (rebreather) mode.

[0120] Conversely, if the detected parameter meets a predetermined condition, for example, if it is lower than a predetermined threshold, the controller determines that the sealed mask is not applied to the patient and the system is operable in the second (high flow) mode. In some examples of detecting the gas concentration parameter, the predetermined condition may include that the detected gas concentration is at or near a predetermined threshold when the threshold corresponds to the gas concentration value corresponding to the ambient air. If the device 100 is not yet operating in the appropriate mode, the controller operates the switching element to provide respiratory assistance in the appropriate mode. Therefore, if the device is providing respiratory assistance in the first mode and the controller determines that the sensor input is lower than the threshold, the control is switched to providing respiratory assistance in the second mode. Conversely, if the device is providing respiratory assistance in the second mode and the controller determines that the sensor input is higher than the threshold, the control is switched to providing respiratory assistance in the first mode. It may be desirable to set the thresholds for CO2 and O2 concentrations slightly higher than the ambient values to reduce false threshold detection due to, for example, indoor ventilation or environmental flow from other sources. The thresholds used by the controller 1010 in sensor-driven automatic switching may be adjustable, for example, by the user or a service technician. In some examples, the threshold triggering the switch from the first mode to the second mode may be the same as the threshold triggering the switch from the second mode to the first mode. Alternatively, these switching conditions may be triggered by different thresholds so that the tolerance and certainty of the switch are obtained and / or the undesirable fluctuations between modes, for example, when one threshold is used, can be reduced.

[0121] In other examples, one or more sensors may detect the pressure within the intake air passage 210. While the device is operating in the second mode, the controller 1010 may receive continuous or periodic inputs from the pressure sensor and compare them to a threshold or range of high flow pressure values known to be consistent with the provision of respiratory assistance in the second (high flow) mode. When the controller detects a pressure increase exceeding the threshold or range of high flow pressure values, the controller identifies that the sealed mask is applied to the patient and controls the switching element of the device to provide respiratory assistance in the first mode. Similarly, while the device is operating in the first mode, the controller 1010 may receive continuous or periodic inputs from the pressure sensor and compare them to a threshold or range of rebreathing pressure values known to be consistent with the provision of respiratory assistance in the first mode. When the controller detects a pressure decrease below the threshold or range of rebreathing pressure values, the controller identifies that the sealed mask is not applied to the patient and controls the device switching element to provide respiratory assistance in the second mode.

[0122] In other examples, one or more sensors may detect pressure and / or flow rate and / or gas concentration within the exhalation path 130 and provide an input to the controller 1010. If the controller 1010 determines that the time-averaged flow rate or O2 concentration of the gas within the exhalation flow path 130 is approximately equal to, close to, or within a certain percentage (e.g., within 90+%) of the flow rate or O2 concentration provided as part of the respiratory assistance, the controller identifies that the mask is applied to the patient and, if the respiratory assistance is in the second mode, controls the switching element of the device to switch the respiratory assistance to the first mode. Conversely, if the controller 1010 determines that the time-averaged flow rate or O2 concentration of the gas within the exhalation flow path 130 is not equal to, not close to, or not within a certain percentage (e.g., within 90%) of the flow rate or O2 concentration provided as part of the respiratory assistance, the controller identifies that the mask is not applied to the patient and, if the respiratory hold is in the first mode, controls the switching element of the device to switch the respiratory assistance to the second mode. In some examples, one or more sensors may also detect pressure and / or flow rate and / or gas concentration within the inhalation path 210 to identify characteristics of the respiratory assistance provided to the patient. It is appropriate to note that characteristics such as the flow rate, O2 concentration, and gas flow pressure provided as part of the respiratory assistance may vary depending on the mode of respiratory assistance provided. It may be preferable to time-average the values of pressure and / or flow rate and / or gas concentration over at least one respiratory cycle (when the patient is breathing spontaneously) to allow for measurement delays.

[0123] Alternatively or additionally, the respiratory assistance provided to the patient may include a controlled component that provides a "signature" in the gas flow that can be used by the controller to confirm whether the mask is applied to the patient. The signature may include variations in characteristics such as the frequency, amplitude, or profile of the pressure and / or flow rate and / or O2 concentration of the gas provided to the patient. The variations may be realized, for example, by a valve such as a proportional valve in the flow path. During the provision of respiratory assistance, when the controller identifies the presence of a signature in the gas received in the expiratory flow path 130, the controller identifies that the mask is applied to the patient and controls the switching element of the device to switch the respiratory assistance to the first mode if the respiratory assistance is in the second mode. Conversely, when the controller identifies the absence of a signature in the gas received in the expiratory flow path 130, the controller identifies that the mask is not applied to the patient and controls the switching element of the device to switch the respiratory assistance to the second mode if the respiratory assistance is in the first mode. In some embodiments, the signature may be provided in only one mode, or different signatures may be provided for different modes of respiratory assistance.

[0124] In an example where the controller 1010 compares the detected flow rate with a reference value or threshold value, the controller may calculate the difference as an absolute value and / or the percentage of the threshold value or the provided respiratory assistance. The controller 1010 may further be configured to display the calculated difference on the user interface 1094. When the controller identifies the difference between the provided value and the detected value, the display of the difference may provide useful data that can indicate the presence of a leak in the system. When the sealed mask is used in the first mode, this display may indicate that the seal of the mask on the patient's face is insufficient.

[0125] The controller 1010 can use and / or combine any one or more of the above-described detection examples to increase the certainty that the conditions for switching are met, thereby reducing the possibility of false detection that could cause incorrect switching. Merely by way of example, one such combination can include the flow rate in the expiratory flow path 130 and CO2 detection, or the flow rate detection in the inspiratory flow path 210 and the gas concentration detection in the expiratory flow path 130. Other combinations can include the pressure detection in the inspiratory flow path 210 and the pressure detection in the expiratory flow path 130, to which the CO2 detection in the expiratory flow path 130 is optionally added.

[0126] For example, any one or more of the pressure, flow rate, or gas concentration detection in the expiratory flow path 130, the pressure detection in the inspiratory flow path 210, and the pressure, flow rate, and / or gas concentration detection in the expiratory or inspiratory flow paths 210, 130 can be used by the controller to control the switching from the second mode to the first mode, and the same or different one or more sensor inputs can be used by the controller to control the switching from the first mode to the second mode in addition. In some cases, it may be desirable for the controller to have higher redundancy or certainty (therefore, more conditions must be met before switching) when switching from the second mode to the first mode due to the release of volatile substances. However, in some cases, it may be desirable to have higher certainty when switching from the first mode to the second mode to ensure that it is safely and / or appropriately stopped before stopping the ventilation or providing the volatile substances in the inspiratory gas flow path.

[0127] In another example, schematically shown in FIG. 13, even when it is inactive (not enabled), a small amount of residual flow is provided in the first and / or second flow paths 1100, 1200, and one or more sensors can be provided at positions S3 and / or S4 upstream of the check valve 149. The residual flow can be on the order of, for example, about 0.5 L / min to about 5 L / min (e.g., if there are check valves 149A, 149B in the flow path, the residual flow keeps these valves open) so that the sensors at positions S3 and / or S4 are in reliable fluid communication with the first gas port 1300. The residual flow can include air instead of O2 to reduce O2 consumption and / or waste.

[0128] In one example, when the device is providing respiratory assistance in the second mode, the residual flow can be maintained to pass over S3 through the rebreathing component 140 to keep the flow path open. The pressure at S3 can be detected periodically / continuously, and the controller 1010 receives the input from the pressure sensor and compares them with a threshold or range of values known to be consistent with the provision of respiratory assistance in the second mode at a specific flow rate. When a pressure increase is detected at S3, the controller identifies that the mask has been applied to the patient and controls the switching element of the device to provide respiratory assistance in the first mode.

[0129] During operation in the first mode, the residual flow held in the second gas flow path 1200 keeps the flow path open. The pressure at S4 is detected periodically / continuously, and the controller 1010 receives the input from the pressure sensor and compares them with a threshold or range of values known to be consistent with the provision of respiratory assistance in the first mode. When a pressure decrease is detected at S4, the controller identifies that the mask has not been applied to the patient and controls the switching element of the device to provide respiratory assistance in the second mode at a flow rate higher than the residual flow rate. The controller can identify an increase or decrease in pressure at S3 and / or S4 by referring to a threshold or range of values that can be an absolute value (e.g., 1 cmH2) or a percentage of the expected pressure for a specific operating mode (e.g., a change from the expected of 20+%).

[0130] In the figure, check valves 149A and B are shown as separate valves upstream of the confluence point between the intake air flows from the first gas flow path 1100 and the second gas flow path 1200. However, the functionality of these valves can be combined into one check valve provided downstream of the confluence point between the intake air flows from the first gas flow path 1100 and the second gas flow path 1200. Alternatively, a valve for preventing reverse flow can be additionally installed at this position downstream of the confluence point. In such an arrangement configuration, in order to prevent reverse flow from exiting into the environment in the first (rebreathing) mode, a check valve may be desirable, for example, downstream or upstream of the humidifier 420 and / or at the switching element 710.

[0131] Alternatively or additionally, the sensor can include one or more proximity sensors such as acoustic (including audible and / or ultrasonic), optical (including infrared), high frequency, pressure (in the intake / exhaust conduit and / or mask cuff), flow rate, electrical conductivity, resistance, temperature, or other sensors, for example, to determine which of the breathing circuits is connected to the patient's airway by the first or second patient interface. Such proximity sensors are described in more detail in International Publication No. WO 2016 / 157105, the content of which is incorporated herein by reference.

[0132] In some examples of automatic (sensor-driven) switching between breathing assistance modes, the controller 1010 may apply timing control to the switching control and apply a delay before controlling the switching element to perform a mode switch when a state to trigger a mode switch is detected. This can avoid false switching resulting from, for example, accidental collapse of the conduit or other movements that are resolved after a few seconds, such as detection errors or transient states. The user interface 1094 may provide a visual and / or other audible countdown timer that provides the user with an indication of when the mode switch will occur. It may also be desirable for the user interface 1094 to provide the user with an option to cancel a mode switch provided by the controller within a predetermined time, for example, if the user becomes aware that an incorrect switching condition has been met. For example, when switching from the first mode to the second mode, the controller may control the operation of one or more of the gas sources 1060, 1600A, 1060B and the flow meters 190C, 190F to stop the supply of the volatile substance provided in the first gas flow path 1100 and / or reduce its flow rate, but otherwise the treatment through the first gas flow path may continue until a predetermined time has elapsed. If the proposed switch is cancelled by the user within the predetermined time, the controller resumes the supply of the volatile substance and the flow from the first gas flow path 1100 to the patient is not stopped.

[0133] The switching mechanism 1370 may include one or more actuators operable by a user, which may be, for example, buttons, switches, knobs, foot-operated switches, or pedals, but are not limited thereto. Alternatively or additionally, the switching mechanism 1370 may include or operatively communicate with one or more of an electronic input device, a touch screen, a voice activation sensor, or the like that is operable with the electronic controller 1010 of the device 1000. One or more actuators of the switching mechanism 1370 may be positioned on or near the first or second patient interface 120, 220 through which exhaled gas is removed or breathing gas is delivered to the patient. By positioning one or more of the actuators at or near the patient end of the breathing conduit that delivers gas to the patient's airway, convenience is provided to the clinician treating the patient throughout an anesthesia phase where it is often necessary to switch the operating mode of the device 1000 and the form of respiratory assistance delivered. Merely positioning the actuator enabling mode selection on the patient side can be more convenient for the clinician and other persons in the vicinity and can lead to time savings. In other arrangements, the device 1000 may be configured to detect that the first patient interface, which is an exhalation patient interface configured to receive exhaled gas from the patient for return to the device, has been attached to the patient and to change the operating mode and flow path selection accordingly.

[0134] In some embodiments, the user interface 1094 may provide an auditory and / or visual output (e.g., a display on a display screen and / or an auditory voice or message) to the user indicating the operating mode in which the device 1000 is operating. Alternatively or additionally, other components of the respiratory assistance system, such as, for example, the gas conduit of the breathing circuit or the patient interface, may include an auditory or visual output element (e.g., a speaker and / or an LED or other lighting element) operable by the controller 1010 to provide an output to the user indicating the operating mode in which the device 1000 is operating. In one example, a predetermined color and / or voice and / or symbol on the output element may be associated with the operation of the device 1000 in a first mode, and a different predetermined color and / or voice and / or symbol may be associated with the operation in a second mode. One or more predetermined colors and / or voices and / or symbols may be selectable and / or definable by the user. By positioning one or more of the output elements at or near the patient end of the breathing circuit that delivers gas to the patient's airway, convenience is provided for the clinician treating the patient to always know the mode in which the device is operating throughout the anesthesia phase.

[0135] It should be understood that the switching mechanism 1370 may include a mechanical, electronic, electromechanical, electromagnetic, pneumatic, or any other suitable switching mechanism to implement the functionality described herein. Further, one or more switching elements may be connectable to the switching mechanism 1370 via wired and / or wireless couplings using techniques that are readily understood and verifiable by those skilled in the art. The switching element may include an actuator with an operating function for the user of the device 1000 to select the required operating mode (and the flow path to be enabled), and may include or consist of any of the described switching elements. In some embodiments, the switching element may include an electronic input device that communicates wirelessly with the controller 1010 of the device 1000 and is positionable to move to another location with respect to the patient 300 and / or the device 1000 and / or the patient interface 120 / 220.

[0136] In some embodiments, one or more switching elements of the switching mechanism 1370 may be operable to control one or more characteristics of the 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.

[0137] For the sake of brevity, the specific functions of the first gas flow path 1100 are not always shown in the figures. However, in a preferred embodiment, the first gas flow path 1100 performs the functions of the anesthesia machine 10 and / or the ventilator 20, and includes a CO2 absorber 141 configured to process the exhaled gas returned in the first mode before recirculating it to the patient, a pressure limiting valve 146 configured to maintain a substantially stable pressure in the device in the first mode, a variable volume section 145 (e.g., using a bellows or bag ventilator) for gas replacement in the first mode, a replenishing gas flow for replenishing the anesthetic gas delivered to the patient in the first mode, and a vaporizer 150 for vaporizing volatile anesthetics into the gas delivered to the patient in the first mode.

[0138] Similarly, for the sake of brevity, the specific functions of the second gas flow path 1200 are not always shown in the figures. However, in a preferred embodiment, the second gas flow path 1200 provides high-flow respiratory assistance as described herein and includes one or more of a flow source 250 or a regulator configured to generate a gas flow through the second gas flow path 1200 in the second mode. A humidifier 420 configured to adjust the gas to a predetermined temperature and / or humidity before delivering it to the first gas port 1300 may also be provided, although this may be omitted in some cases.

[0139] In some embodiments, the switching mechanism can be provided by using the first and second patient interfaces 120, 220 simultaneously. Therefore, when the first (expiratory) and second (inspiratory) patient interfaces are applied to the patient simultaneously, the first gas flow path 1100 is enabled and the device 1000 is configured to operate in the first mode, and when only the second (inspiratory) patient interface is applied to the patient, the second gas flow path 1200 is enabled and the device 1000 is configured to operate in the second mode. In one arrangement, the first patient interface 120 is a mask that can seal over the second patient interface 220, which is a nasal cannula, without obstructing the flow through the cannula. The inspiratory flow is delivered via the cannula and the expiratory gas is returned via the face mask. This arrangement can be deployed to deliver anesthesia in a closed system that utilizes a cannula for delivering anesthetic to the patient and a mask for returning the expiratory gas. A pressure sensor can be used to identify that the mask is applied to the patient and sealed over the cannula, and when the target pressure is detected at the mask (e.g., inside the mask or in the mask cuff, or by a pressure sensor on the cannula body), the switching mechanism 1370 is triggered, thereby enabling the first gas flow path 1100 to provide anesthetic through the nasal cannula. International Publication No. WO 2015 / 145390, owned by the applicant of the present application, discloses a mask suitable for such a situation, which is incorporated herein by reference.

[0140] Figures 14-16 show an example of how to switch between the flow paths within device 1000 disclosed in the present application to configure a device that is used in different modes of respiratory assistance by using the first and second patient interfaces 120, 220 simultaneously or separately. Device 1000 provides a first gas port 1300 configured to be coupled to a first (inspiratory) conduit 210. A second gas port 1400 is provided and coupled to a second (expiratory) conduit 130 to return exhaled gas from the patient through the first patient interface 120. When any flow path of device 1000 is enabled, gas is provided to the patient's airway through conduit 210 and the second patient interface 220. When the first flow path 1100 is enabled, device 1000 operates in a first mode to provide gas to the patient using first flow parameters and return exhaled gas from the patient to the second gas port 1400 through the first patient interface 120 and the second conduit 130. When the second gas flow path 1200 is enabled, device 1000 operates in a second mode to provide gas to the patient using second flow parameters. The first and second flow parameters each include or correspond to a first and a second flow rate. In some embodiments, the first flow rate is less than 15 L / min and the second flow rate is higher 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. However, it should be understood that the first flow parameter may alternatively or additionally include pressure and / or volume parameters.

[0141] As shown in FIG. 14, the second patient interface 220 is an unsealed patient interface shown as a nasal cannula 224 in fluid communication with the first conduit 210, and the first patient interface is a sealed patient interface shown as a mask 124. In FIG. 15, the nasal cannula 224 and the mask 124 are applied to the patient simultaneously, whereby the device 1000 is operable in a first mode to provide anesthesia ventilation, and the mask 124 is configured to seal over the nasal cannula 224 and the patient 300. In this arrangement, gas is delivered to the patient via the first conduit 210, and exhaled gas from the patient is returned from the patient to the device 1000 via the mask 124 and the second conduit 130. In FIG. 14, only the unsealed patient interface, e.g., the nasal cannula 224, is applied to the patient to provide gas in a second mode that provides high-flow respiratory assistance to the patient's airway. In some embodiments, the second conduit 130 is unnecessary or does not operate in the second mode.

[0142] In an alternative embodiment, gas may be delivered to the patient via the second conduit 130 and the mask 124, and exhaled breath from the patient is returned from the patient to the device 1000 via the nasal cannula 224 and the first conduit 210. In such an embodiment, the second conduit 130 is an inspiratory conduit and the first conduit 210 is an expiratory conduit.

[0143] Advantageously, when the sealed mask 124 is physically applied to the unsealed cannula 224 as illustrated in FIG. 14, the patient's own airway is utilized to provide a gas flow path between the cannula and the mask. This enables respiratory gas to be provided via the inspiratory conduit and exhaled gas to be removed via the expiratory conduit, and a Y-piece connector, such as is commonly used in a rebreathing patient circuit to connect the inspiratory and expiratory limbs, is not used. Further, when the mask 124 is removed, the cannula 224 remains in place and can provide respiratory assistance in the second operating mode without the need to apply another patient interface to the patient. The reduction in components by eliminating the Y-piece connector and the simplification of components and patient intervention steps results in cost and time savings and simplifies the manner of the anesthesia procedure.

[0144] FIG. 16 provides an arrangement configuration for the operation of the device 1000 in the third mode. In the third mode, ventilatory rebreathing is delivered by the endotracheal tube 126. Here, the first conduit 210 is disconnected from the nasal cannula 224 and connected to the inlet of the coupling 620. Similarly, the second conduit 130 is disconnected from the mask 124 and connected to the outlet of the coupling 620. The patient end of the coupling 620 is connected to the endotracheal tube 126 and provides the functions of both the first and second patient interfaces in the third mode. In some embodiments, the endotracheal tube 126 can be other types of patient interfaces, such as a laryngeal mask or a tracheostomy interface or a mask, etc. In the third mode, gas containing a third flow parameter that may include one or more of a flow rate, a pressure, or a volume parameter can be delivered to the patient. Although not shown, during the operation of the device in the third mode using an endotracheal tube, a laryngeal mask, or a tracheostomy interface, the second patient interface 220 including the nasal cannula 224 can remain in place above the patient but is disconnected from the first conduit 210. This can be advantageous in that it allows the user to easily switch between the third and first modes and / or the third and second modes of respiratory assistance.

[0145] The advantage of mode switching according to the example described in connection with FIGS. 14 - 16 is that it is possible to provide a plurality of modes of respiratory assistance to the patient using a single inspiratory conduit and a single expiratory conduit. This reduces the cost and complexity of the respiratory circuit utilized in the treatment of the patient.

[0146] FIG. 17 is a schematic view of a novel connector 1700 that can be used to facilitate the exchange of components for delivering respiratory assistance in a first mode and a second mode, as described in connection with the embodiments of FIGS. 14-16. The connector 1700 is configured to couple with a standard Y-piece connector 1750. In normal use, the Y-piece connector 1750 is configured at port 1755 to couple with a conduit that provides a flow of breathing gas to a mask 124 of the type shown in FIGS. 14 and 15. The Y-piece connector 1750 receives the flow of gas from the first conduit 210 and provides an outflow path for exhaled gas from the patient via the second conduit 130. When used as shown in FIG. 15, the mask 124 forms a sealed interface with the patient's airway, delivers gas that may contain anesthetic via the nasal cannula 224, and returns exhaled gas to the device 1000 via the mask 124 and the second conduit 130.

[0147] To facilitate interoperability between different patient interfaces, a novel connector 1700 can be used that provides a wall 1720 configured to project within a Y-piece connector 1750. When connected, the wall 1720 separates the flow into separate limbs 1710 and 1730. In use, the connector 1700 is configured to couple the first limb 1710 to a conduit attached to a nasal cannula 224 and the second limb 1730 to a conduit attached to a face mask 124. By the separating wall 1720, the inspiratory flow to the cannula 224 (see FIGS. 14 and 15) remains separated from the expiratory flow received from the mask 124 (when used in the configuration of FIG. 15). To quickly switch to the patient interface required to deliver assistance in a third mode, the connector 1700 can be removed from the Y-piece connector 1750, and the Y-piece connector 1750 is instead coupled to an endotracheal tube 126. Advantageously, the connector 1700 is used to simultaneously couple the Y-piece connector 1750 to the nasal cannula 224 and the mask 124 with fewer component separations / reconnections and less room for error for quick connection of the endotracheal tube 126 and can be connected and disconnected. When switching back to the first support mode with the mask 124 configured to seal over the nasal cannula 224 (as in FIG. 15), the endotracheal tube 126 is disconnected from the Y-piece connector 1750 and the connector 1700 is reconnected to simultaneously reconnect the first conduit 210 and the second conduit 130 to the cannula 224 and the mask 124.

[0148] Figure 18 is a schematic view of another connector 1800 that serves as an alternative to the standard Y-piece connector 1750 provided for use in the arrangement shown in Figure 15. By using connector 1800, mask 124 can be used to remove exhaled gas via the second conduit 130. To operate in the first mode (Figure 15), connector 1800 remains connected in place between mask 124 and the second conduit 130, but is disconnected from the first conduit 210 that is coupled to nasal cannula 224 instead. The one-way valve 1810 biases the exhalation flow in the first conduit 210 toward mask 124 and operates to prevent exhaled gas from the mask from exiting into the atmosphere, which is because no intake conduit is attached to connector 1800 in this mode of operation. To operate in the third mode (Figure 16), the first conduit 210 can be reconnected to connector 1800, and mask 124 can be disconnected and replaced with a connection to the endotracheal tube 126. The advantage of this arrangement is that connector 1800 can be used in delivering respiratory assistance in both modes shown in Figures 9 and 10, while, on the one hand, eliminating the need to cut and reconnect to the second conduit 130 required to remove gas as in the case of a standard Y-piece connector.

[0149] FIG. 19 is a schematic diagram of another novel connector 1900 configured to be used in an embodiment where nasal cannula 224 is used to deliver different modes of respiratory assistance. Connector 1900 is connectable with three conduits each providing fluid communication with a first inspiratory gas flow path 210A configured to provide a gas flow for delivery of nasal high flow respiratory assistance, a second inspiratory gas flow path 210B configured to provide a gas flow for delivery of anesthesia ventilation, and an expiratory gas flow path 130 for exhaling exhaled gas from the patient. A switch 1910 (such as a switching valve, solenoid, etc.) is provided for changing the internal flow path of connector 1900 when different assistance modes are selected. When nasal cannula 224 is used for delivery of anesthesia rebreathing, switch 1910 is in the position shown by the solid line, enabling delivery of respiratory gas (including anesthetic) from the second inspiratory gas flow path 210B and providing a path for expiratory gas 130. During manual rebreathing, a bag mask is applied over nasal cannula 124 and sufficient pressure (e.g., by attachment) can be applied such that the cannula can provide both an inspiratory and an expiratory flow path. For high flow respiratory assistance, switch 1910 is in the position (diagonal position) shown by the dashed line. Switch 1910 can be operatively coupled with other switching elements operable by a user (or device controller 1010 using user interface 1094) to configure the device to operate in different assistance modes within device 1000.

[0150] Figures 20 and 21 are schematic views of connectors 1950A and 1950B, which are modified forms of the connector of FIG. 19, and are connected to both the nasal cannula 224 and the mask 124. These connectors 1950A and 1950B deliver nasal high flow when the switch 1910 is in the dashed (diagonal) position. When the switch 1910 is in the solid (vertical) position, anesthesia rebreathing can be provided by the cannula 224, the exhaled gas is removed by the application of the face mask 124, and the device is arranged as shown in FIG. 15. FIG. 20 shows the connector 1950A in which all flow paths are within a single connector piece. FIG. 21 shows the connector 1950B that includes an intake flow path having a connection for the nasal cannula 124 and another conduit used to provide a second (exhalation) conduit 130 attached to the mask 124.

[0151] Device 1000 that can use the patient interface shown in FIGS. 14 - 16 can include a controller 1010 that communicates with a flow source / regulator 250, and one or more sensors and / or user interfaces that communicate with the controller and provide an input to the controller to control the flow source / regulator to provide a gas flow in a first or second mode. The sensors and / or user interfaces can also be configured to provide an input to the controller to control the flow source / regulator to provide a gas flow in a third mode.

[0152] The terms "first", "second", and "third" are merely labels for designating functions of the present disclosure and are not to be considered explanatory. Thus, reference to the "second" function does not require the provision of the "first" such function, and reference to the "third" function does not require the provision of the "first" and "second" such functions. For example, the provision of a second patient interface (which can be a high flow patient interface) in the present disclosure does not require the provision of a first patient interface (which can be a rebreathing patient interface).

[0153] Advantages Embodiments of the present disclosure provide a device that can deliver high-flow respiratory assistance and rebreathing respiratory assistance for the delivery of anesthesia and / or ventilation, and can easily switch between these respiratory assistance modes. That is, according to embodiments of the present disclosure, a clinician can easily switch between high-flow respiratory assistance and the deployment of rebreathing respiratory assistance for patient intubation / ventilation. This reduces the total number of components, simplifies the work environment, and makes it easier for an anesthesiologist to perform tasks required during procedures that include high-flow therapy or respiratory assistance in addition to the administration of anesthesia. This can be advantageous, for example, when preparing a patient for intubation or when withdrawing a patient from sedation. In this arrangement, the functions for user control for delivering high-flow respiratory assistance can be conveniently arranged together with the functions for user control for delivering sedation or deeper anesthesia. Embodiments disclosed herein can also simplify and reduce the number of facilities and conduits that occupy valuable space in a clinical setting.

[0154] When switching from the rebreathing mode to the high-flow mode, for safety reasons, it is desirable that the transition stops the delivery of anesthetic gas. (For example, when the mask is removed from the patient) If O2 is delivered uncontrollably outside the first gas flow path, there is a risk of fire, there may be a waste of anesthetic gas, and the anesthetic gas may be unintentionally released into the surgical environment, contaminating the high-flow respiratory assistance gas and potentially affecting the ability of people in the surgical environment. Embodiments of the present invention can address one or more of these problems.

[0155] This specification also describes various embodiments, devices, connectors, assemblies, accessories, devices, etc. that achieve switching of the respiratory assistance mode. Some of these provide the convenience of controlling mode selection and / or displaying the operating mode when the user is not located at the "machine". Some embodiments provide automatic selection of the operating mode by monitoring gas characteristics such as gas pressure, O2 and CO2 concentrations in the exhaled gas. These features not only improve the convenience and operability of the devices providing these respiratory assistance modes, but also have the ability to improve patient safety.

[0156] It should be understood that various changes, additions and / or substitutions can be made to the above-described members without departing from the scope of the invention as defined in the provisional patent claims appended hereto.

[0157] The present invention can also be broadly described as existing in any or all combinations of two or more of the parts, elements and features individually or collectively mentioned or shown in the specification of this application. In the above description, when referring to a whole or component having known equivalents, those wholes are incorporated herein as if individually shown.

[0158] In this specification (including the provisional patent claims), when any or all of the terms "comprise", "comprises", "comprised" or "comprising" are used, they should be construed as specifying the presence of the recited features, wholes, steps or components, but not as precluding the presence of one or more other features, wholes, steps or components, or groups thereof.

[0159] Future patent applications may be made based on this application or claiming its priority. The following patent claims are provided by way of example only and are not to be understood as limiting the scope of what may be claimed in future applications. Features may be added or deleted from the provisional patent claims at a later date so as to further define or redefine the invention.

Claims

1. In a device for providing respiratory support to a patient, (a) First gas flow path and (b) Second gas flow path and (c) A first gas port configured to receive gas from either the first gas passage or the second gas passage, (d) A switching mechanism that can be operated to switch the flow to the first gas port between the first gas flow path and the second gas flow path, A device comprising the gas from the first gas port being provided to the patient for respiratory support.

2. The device according to claim 1, wherein when the switching mechanism operates to allow flow from one of the gas passages to the first gas port, flow from the other of the gas passages to the first gas port is blocked.

3. The device according to claim 1, wherein the switching mechanism includes one or more valves configured to prevent backflow in the other gas passage when the switching mechanism is operating to allow flow from one of the gas passages to the first gas port, upstream of the confluence point between the first gas passage and the second gas passage.

4. The device according to claim 1, wherein the switching mechanism is operatively connected to one or more flow meters configured to stop the gas flow to the gas passage that does not provide gas flow to the first gas port in accordance with the operation of the switching mechanism.

5. The device according to claim 1, wherein the switching mechanism is operatively coupled to one or more flow meters that are operable to control the gas flow to the gas channel that provides the gas flow to the first gas port in accordance with the operation of the switching mechanism.

6. The device according to any one of claims 1 to 5, comprising a controller that operates to communicate operationally with the switching mechanism and to control the device in order to deliver respiratory support to the patient.

7. The device according to claim 6, wherein the controller receives input from one or more sensors and determines whether the first patient interface has been applied to the patient.

8. The device according to claim 7, wherein when it is determined that the first patient interface has been applied to the patient, the controller automatically controls the device to provide respiratory support in a first mode, and when it is determined that the first patient interface has been removed from the patient, the controller automatically controls the device to provide respiratory support in a second mode.

9. The aforementioned controller, In the respiratory pathway that delivers gas to the patient, Between the first gas port in the device and the confluence point where the returned gas in the device meets the fresh gas supply, In the exhalation channel that returns gas from the patient to the device, Between the second gas port that receives the gas returned from the patient and the confluence point within the device, In the gas flow downstream of the flow generator or flow mixer of the aforementioned device The device according to claim 7, which receives input from one or more sensors at one or more locations selected from the group including the following:

10. The device according to claim 9, wherein the one or more sensors are of a sensor type selected from the group including pressure sensors, flow sensors, and O2 sensors.

11. The aforementioned controller, An exhalation channel for returning gas from the patient to the device, and In a device having a rebreathing circuit and a CO2 absorber, between the second gas port that receives the gas returned from the patient and the CO2 absorber within the device The device according to claim 7, which receives input from one or more CO2 sensors at one or more locations selected from the group including the following.

12. The device according to claim 8, wherein the controller receives inputs from a plurality of sensors and determines whether or not the first patient interface has been applied to the patient, thereby reducing erroneous switching between the first mode and the second mode.

13. The device according to claim 8, wherein the controller controls the device to provide a residual gas flow in one or both of the first gas flow path and the second gas flow path for continuous or regular monitoring of the gas, and optionally the residual gas flow is about 0.5 L / min to about 5 L / min.

14. The device according to claim 6, wherein the controller controls a user interface that provides either an auditory or visual mode indicator representing the current operating mode of the device.

15. The device according to claim 6, comprising a user interface configured to communicate operationally with the controller and to receive user input corresponding to one or more parameters of the respiratory support to be provided to the patient.

16. The device according to claim 6, wherein the controller is configured to receive a user input that causes the switching mechanism to switch the flow to the first gas port between the first gas flow path and the second gas flow path.

17. The device according to any one of claims 1 to 5, wherein the first gas port is a common gas outlet port connectable to a first conduit for delivering gas to a patient from either the first gas flow path or the second gas flow path.

18. The device according to any one of claims 1 to 5, comprising a humidifier configured to adjust the gas to a predetermined temperature and / or humidity before delivering it to the patient through one or both of the first and second gas channels.

19. The device according to any one of claims 1 to 5, wherein the device is operable to provide a gas flow in the second gas flow path at a flow rate selectable from an available range of about 20 L / min to about 100 L / min.

20. The first gas channel includes a rebreathing gas channel that receives and processes exhaled gas returned from the patient, and / or The second gas flow path includes a high-flow gas flow path. The device according to any one of claims 1 to 5.

21. (a) A rebreathing mode in which gas flows from the rebreathing gas channel to the first gas port and is supplied to the patient, and the exhaled patient gas is returned to the device via a second gas port that can be connected to a second conduit configured to receive exhaled gas from the patient, (b) The device according to claim 20, configured to operate in a high-flow mode, wherein the discharged patient gas is not returned to the device, and the gas flows from the high-flow gas channel to the first gas port and is provided to the patient.

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