Patent Description:
Altitude effects can influence athletic performance. Some athletes have found it advantageous to spend time, such as live and/or train, at relatively high altitudes to gain a competitive edge, commonly known as altitude training. Not to be limited by theory, altitude training has several beneficial potential physiological effects. At high altitude the partial pressure of oxygen is reduced due to the reduced barometric pressure, even though the actual concentration of oxygen remains relatively constant. Over the course of multiple weeks, a person's body may adapt to this relatively low oxygen environment by increasing mass of red blood cells and hemoglobin, and/or by altering muscle metabolism. These physiological changes can be shown to have follow up positive effects, particularly in terms of a raised VO<NUM> max, which is the maximum rate at which oxygen can be used be consumed by the body. VO<NUM> max is strongly linked to aerobic capacity, and in turn has effects on speed, strength, endurance and recovery.

There can be a large number of variables associated with altitude training, not limited to types of exercise, levels of altitude/oxygen concentration, length of therapy sessions, total length of therapy regime, length of time since leaving altitude, whether or not to remain at altitude for training sessions, whether or not to remain at altitude outside of training sessions, efficacy of simulated altitude, optimum ways to deliver simulated altitude, whether to control to inspired oxygen or blood oxygen saturation, as well as determining the exact underlying mechanism behind the physiological changes. As actually being at altitude poses multiple challenges in terms of cost, inconvenience and difficulty to alter the exact altitude as noted above, methods of generating an artificial high altitude environment have been investigated. As one theory for the effects of altitude training is the reduced partial pressure of oxygen, this could be accurately mimicked by adding one, two, or more hypoxic gases, such as nitrogen or other gases to ambient air, resulting in a gas with a reduced oxygen concentration. Generating a hypoxic environment can be shown to artificially replicate the effects of being at altitude. Systems and methods that can more efficiently, effectively, safely, and conveniently replicate such altitude and other effects are needed.

<CIT> discloses a system and a method for oxygenating a patient in relation to anesthesia using high flow gas delivery, wherein the oxygenation requirements of the patient are determined before or during anesthesia. <CIT> discloses an apparatus for the delivery of hypoxic air to a user comprising a biofeedback means of control wherein at least one physiologically measurable parameter of the user is constantly measured. <CIT> discloses a system, device, and method for automatically inducing, maintaining, or controlling hypoxia in a patient, wherein at least one physiological parameter of the patient is monitored and the delivery of the hypoxic gas mixture is automatically controlled based on a value of the physiological parameter.

The present invention is directed to a nasal high flow system according to claim <NUM>. Additional features and embodiments of the invention are defined in the dependent claims.

SUMMARY OF THE DISCLOSURE In a first aspect, there is provided a nasal high flow system configured for providing a hypoxic flow of gases to a user includes an apparatus comprising a gas flow path, an ambient air inlet, and a hypoxic gas source inlet configured to connect to a hypoxic gas source and configured to create a hypoxic gas composition upon mixing of ambient air and the hypoxic gas; a user interface comprising a nasal cannula comprising nasal prongs; a gas flow generation element configured to deliver the hypoxic gas composition to nares of the user at a predetermined high flow rate of at least about <NUM> liters/minute; a sensor configured to measure a physiological parameter of the user, wherein the physiological parameter is blood oxygen saturation; and a controller configured to automatically control the delivery of the hypoxic gas composition based on the measured physiological parameter; wherein the nasal cannula is non-sealed.

In some configurations, the gas flow generation element can comprise one or more of a blower, a compressor, a pressurized tank, or a gas source in the wall.

In some configurations, the system can further include the hypoxic gas source.

In some configurations, the hypoxic gas source can comprise a hypoxic gas reservoir.

In some configurations, the hypoxic gas can comprise enriched nitrogen.

In some configurations, the gas flow generation element can be configured to deliver the hypoxic gas composition sufficient to meet the peak inspiratory demand of the user.

In some configurations, the system can further include a heating element configured to heat the hypoxic gas composition prior to reaching the nares of the user. In some configurations, the heating element can comprise a heater plate. In some configurations, the heating element can comprise a heater wire.

In some configurations, the system can further include a humidification element configured to humidify the hypoxic gas composition prior to reaching the nares of the user. The humidification element may be a humidification chamber.

In some configurations, the humidification element can be configured to humidify the hypoxic gas composition to a relative humidity of at least about <NUM>%. The humidification element can be configured to humidify the hypoxic gas composition to a relative humidity of at least about <NUM>%. The humidification element can be configured to humidify the hypoxic gas composition to a relative humidity of at least about <NUM>%. The humidification element can be configured to humidify the hypoxic gas composition to a relative humidity of at least about <NUM>%. The humidification element can be configured to humidify the hypoxic gas composition to a relative humidity of at least about <NUM>%.

In some configurations, the system can further include a sensor configured to measure a peak inspiratory demand of the user; and the system can be configured to adjust the flow rate based upon the measured peak inspiratory demand.

In some configurations, the system can be configured to deliver the hypoxic gas in an oxygen concentration of between about <NUM>% and about <NUM>%. The system can be configured to deliver the hypoxic gas in an oxygen concentration of between about <NUM>% and about <NUM>%. The system can be configured to deliver the hypoxic gas in an oxygen concentration of between about <NUM>% and about <NUM>%. The system can be configured to deliver the hypoxic gas in an oxygen concentration of between about <NUM>% and about <NUM>%. The system can be configured to deliver the hypoxic gas in an oxygen concentration of between about <NUM>% and about <NUM>%. The system can be configured to deliver the hypoxic gas in an oxygen concentration of between about <NUM>% and about <NUM>%.

In some configurations, the controller can be configured to automatically control the delivery of the hypoxic gas composition by adjusting an amount of hypoxic gas mixed into the hypoxic gas composition. In some configurations, the controller can be configured to automatically controlling the delivery of the hypoxic gas composition by adjusting an amount of enriched nitrogen mixed into the hypoxic gas composition.

In some configurations, the physiological parameter can further comprise at least one selected from the group consisting of: heart rate, respiratory rate, heart rate variability, and blood pressure.

In some configurations, the system can further include an alarm configured to notify the user when the physiological parameter deviates from a pre-selected range for at least a pre-determined period of time.

In some configurations, the alarm can comprise one of a visual, auditory, or tactile alarm.

In some configurations, the controller can be configured to titrate the composition of the hypoxic gas composition to achieve a blood oxygen saturation of the user of less than about <NUM>%. The controller can be configured to titrate the composition of the hypoxic gas composition to achieve a blood oxygen saturation of the user of between about <NUM>% and about <NUM>%. The controller can be configured to titrate the composition of the hypoxic gas composition to achieve a blood oxygen saturation of the user of between about <NUM>% and about <NUM>%. The controller can be configured to titrate the composition of the hypoxic gas composition to achieve a blood oxygen saturation of the user of between about <NUM>% and about <NUM>%. The controller can be configured to titrate the composition of the hypoxic gas composition to achieve a blood oxygen saturation of the user of between about <NUM>% and about <NUM>%.

In some configurations, the system can further include a sensor configured to sense the oxygen concentration of the hypoxic gas composition.

In some configurations, the system can further include a display, wherein the system is configured to output the sensed oxygen concentration in real time to the display.

In some configurations, the system can be further configured to correlate the sensed oxygen concentration to an altitude equivalent using a processor, and outputting the altitude equivalent in real time to the display.

In some configurations, the system can be further configured to obtain a target oxygen concentration of the hypoxic gas composition based on the blood oxygen saturation.

In some configurations, the system can be further configured to achieve the target oxygen concentration based on the sensed oxygen concentration.

In some configurations, the controller can be configured to achieve the target oxygen concentration by controlling a hypoxic gas inlet valve.

In some configurations, the controller can be configured to alter a flow rate of the hypoxic gas into the hypoxic gas composition.

In some configurations, the gas flow generation element can be configured to deliver the hypoxic gas composition to the nares of the user at a predetermined flow rate of at least about <NUM> liters/minute. The gas flow generation element can be configured to deliver the hypoxic gas composition to the nares of the user at a predetermined flow rate of at least about <NUM> liters/minute. The gas flow generation element can be configured to deliver the hypoxic gas composition to the nares of the user at a predetermined flow rate of at least about <NUM> liters/minute. The gas flow generation element can be configured to deliver the hypoxic gas composition to the nares of the user at a predetermined flow rate of at least about <NUM> liters/minute. The gas flow generation element can be configured to deliver the hypoxic gas composition to the nares of the user at a predetermined flow rate of at least about <NUM> liters/minute. The gas flow generation element can be configured to deliver the hypoxic gas composition to the nares of the user at a predetermined flow rate of at least about <NUM> liters/minute.

In some configurations, the nasal high flow system can be a high flow device.

In some configurations, the high flow device can be portable.

In some configurations, the hypoxic gas composition can comprise at least one physiologically inert gas. In some configurations, the hypoxic gas composition can comprise nitrogen.

In some configurations, heating the hypoxic gas composition can be sufficient to inactivate a pathogen of interest.

In some configurations, the pathogen of interest can be a human rhinovirus or influenza.

In some configurations, humidifying and heating the hypoxic gas composition can comprise humidifying and heating the hypoxic gas composition to a dew point temperature of between about <NUM> and about <NUM>. Humidifying and heating the hypoxic gas composition can comprise humidifying and heating the hypoxic gas composition to a dew point temperature of between about <NUM> and about <NUM>. Humidifying and heating the hypoxic gas composition can comprise humidifying and heating the hypoxic gas composition to a dew point temperature of between about <NUM> and about <NUM>. Humidifying and heating the hypoxic gas composition can comprise humidifying and heating the hypoxic gas composition to a dew point temperature of between about <NUM> and about <NUM>. Humidifying and heating the hypoxic gas composition can comprise humidifying and heating the hypoxic gas composition to a dew point temperature of about <NUM>.

In some configurations, humidifying the hypoxic gas composition can comprise humidifying the hypoxic gas composition to a relative humidity of at least about <NUM>%. Humidifying the hypoxic gas composition can comprise humidifying the hypoxic gas composition to a relative humidity of at least about <NUM>%. Humidifying the hypoxic gas composition can comprise humidifying the hypoxic gas composition to a relative humidity of at least about <NUM>%. Humidifying the hypoxic gas composition can comprise humidifying the hypoxic gas composition to a relative humidity of at least about <NUM>%. Humidifying the hypoxic gas composition can comprise humidifying the hypoxic gas composition to a relative humidity of at least about <NUM>%.

In some configurations, an oxygen concentration of the hypoxic gas composition can be between about <NUM>% and about <NUM>%. An oxygen concentration of the hypoxic gas composition can be between about <NUM>% and about <NUM>%. An oxygen concentration of the hypoxic gas composition can be between about <NUM>% and about <NUM>%. An oxygen concentration of the hypoxic gas composition can be between about <NUM>% and about <NUM>%. An oxygen concentration of the hypoxic gas composition can be between about <NUM>% and about <NUM>%. An oxygen concentration of the hypoxic gas composition can be between about <NUM>% and about <NUM>%.

In some configurations, the measured physiological parameter can further comprise at least one selected from the group consisting of: heart rate, respiratory rate, heart rate variability, and blood pressure.

In some configurations, automatically controlling the delivery of the hypoxic gas composition can comprise adjusting an amount of hypoxic gas mixed into the hypoxic gas composition.

In some configurations, notifying the user can comprise activating a visual, auditory, or tactile alarm.

In some configurations, automatically controlling the delivery of the hypoxic gas can comprise titrating the composition of the hypoxic gas composition to achieve a blood oxygen saturation of less than about <NUM>%. Automatically controlling the delivery of the hypoxic gas can comprise titrating the composition of the hypoxic gas composition to achieve a blood oxygen saturation of between about <NUM>% and about <NUM>%. Automatically controlling the delivery of the hypoxic gas can comprise titrating the composition of the hypoxic gas composition to achieve a blood oxygen saturation of between about <NUM>% and about <NUM>%. Automatically controlling the delivery of the hypoxic gas can comprise titrating the composition of the hypoxic gas composition to achieve a blood oxygen saturation of between about <NUM>% and about <NUM>%. Automatically controlling the delivery of the hypoxic gas can comprise titrating the composition of the hypoxic gas composition to achieve a blood oxygen saturation of between about <NUM>% and about <NUM>%.

In some configurations, titrating the composition of the hypoxic gas composition can comprise altering a flow rate of nitrogen into the hypoxic gas composition.

In some configurations, the hypoxic gas composition can be delivered to the user at a flow rate of at least about <NUM> liters/minute. The hypoxic gas composition can be delivered to the user at a flow rate of at least about <NUM> liters/minute. The hypoxic gas composition can be delivered to the user at a flow rate of at least about <NUM> liters/minute. The hypoxic gas composition can be delivered to the user at a flow rate of at least about <NUM> liters/minute. The hypoxic gas composition can be delivered to the user at a flow rate of at least about <NUM> liters/minute. The hypoxic gas composition can be delivered to the user at a flow rate of at least about <NUM> liters/minute.

In some configurations, the hypoxic gas source can comprise a reservoir.

In some configurations, the hypoxic gas comprises a physiologically inert gas. The hypoxic gas can comprise enriched nitrogen.

In some configurations, the heating element and the humidification element can be configured to heat and humidify the hypoxic gas composition to a dew point temperature of between about <NUM> and about <NUM>. The heating element and the humidification element can be configured to heat and humidify the hypoxic gas composition to a dew point temperature of between about <NUM> and about <NUM>. The heating element and the humidification element can be configured to heat and humidify the hypoxic gas composition to a dew point temperature of between about <NUM> and about <NUM>. The heating element and the humidification element can be configured to heat and humidify the hypoxic gas composition to a dew point temperature of between about <NUM> and about <NUM>. The heating element and the humidification element can be configured to heat and humidify the hypoxic gas composition to a dew point temperature of about <NUM>.

In some configurations, the system can further include a sensor configured to measure a physiological parameter of the user; and a controller configured to automatically control the delivery of the hypoxic gas composition based on the measured physiological parameter.

In some configurations, the system can be further configured to achieve the target oxygen concentration by controlling a hypoxic gas inlet valve.

In some configurations, delivering the hypoxic gas can be sufficient to meet peak inspiratory demand of the user.

In some configurations, heating the hypoxic gas composition can comprise heating the hypoxic gas composition to a temperature of between about <NUM> and about <NUM>. Heating the hypoxic gas composition can comprise heating the hypoxic gas composition to between about <NUM> and about <NUM>. Heating the hypoxic gas composition can comprise heating the hypoxic gas composition to about <NUM>.

In some configurations, the user interface can comprise a mask.

In some configurations, the heating element can be configured to heat the hypoxic gas composition to a temperature of between about <NUM> and about <NUM>. The heating element can be configured to heat the hypoxic gas composition to between about <NUM> and about <NUM>. The heating element can be configured to heat the hypoxic gas composition to between about <NUM> and about <NUM>. The heating element can be configured to heat the hypoxic gas composition to about <NUM>.

In some configurations, the heating element and the humidification element can be configured to heat and humidify the hypoxic gas composition to a dew point temperature of between about <NUM> and about <NUM>. The heating element and the humidification element can be configured to heat and humidify the hypoxic gas composition to a dew point temperature of between about <NUM> and about <NUM>. The heating element and the humidification element can be configured to heat and humidify the hypoxic gas composition to a dew point temperature of between about <NUM> and about <NUM>. The heating element and the humidification element can be configured to heat and humidify the hypoxic gas composition to a dew point temperature of about <NUM>.

In some configurations, providing can comprise simulating a first altitude.

In some configurations, the system can include a screen configured to display an altitude equivalent of the altitude or fitness training.

In some configurations, the system can include a screen configured to display an SpO<NUM> of the user.

In some configurations, the screen can comprise a touchscreen.

In some configurations, the system can include user input devices for the user to select an altitude equivalent of the altitude or fitness training.

In some configurations, the altitude equivalent can be based on an oxygen concentration.

In some configurations, the oxygen concentration can be an FdO<NUM> set point or a sensed oxygen concentration.

In some configurations, the user input devices can comprise one or more buttons.

In some configurations, the user input devices can comprise a touchscreen.

In some configurations, the controller can be configured to vary the oxygen concentration of the hypoxic gas composition gradually. The controller can be configured to vary the oxygen concentration of the hypoxic gas composition in a series of step changes. The controller can be configured to vary the oxygen concentration of the hypoxic gas composition in a step change.

In some configurations, the controller can be configured to provide the hypoxic gas composition to simulate a first altitude.

In some configurations, the controller can be configured to vary the oxygen concentration of the hypoxic gas composition to simulate a second altitude lower than the first altitude.

In some configurations, the controller can be configured to provide a gas composition substantially the same as ambient air prior to providing the hypoxic gas composition.

In some configurations, the controller can be configured to vary the oxygen concentration of the hypoxic gas composition responsive to a change in the user's SpO<NUM>.

In some configurations, they system can comprise a sensor configured to measure the user's SpO<NUM>.

In some configurations, the system can comprise a humidification chamber.

In some configurations, the system can comprise a heating element.

In some configurations, the controller can be configured to automatically control the delivery of the hypoxic gas composition by adjusting an amount of hypoxic gas mixed into the hypoxic gas composition. In some configurations, the system further comprises a sensor configured to sense the oxygen concentration of the hypoxic gas composition. In some configurations, the system can be further configured to obtain a target oxygen concentration of the hypoxic gas composition based on the blood oxygen saturation.

These and other features, aspects, and advantages of the present disclosure are described with reference to the drawings of certain embodiments, which are intended to schematically illustrate certain embodiments and not to limit the disclosure.

Although certain examples are described below, those of skill in the art will appreciate that the present disclosure extends beyond the specifically disclosed examples and/or uses and obvious modifications and equivalents thereof. Thus, it is intended that the scope of protection of the present invention herein disclosed should not be limited by any particular examples described below but rather limited by the scope of the appended claims.

In some configurations, systems and methods can reduce the oxygen content of inspired air as a mechanism of simulating being at a higher altitude, improving athletic performance, and other medical and/or wellness benefits. One objective of this is to stimulate the body to produce more red blood cells, and thus oxygen carrying capacity as a way of increasing cardiovascular endurance. In some cases, the systems and methods can be used for a time period sufficient to stimulate erythropoiesis such that the user's hemoglobin level increases by about or at least about <NUM>%, <NUM>%, <NUM>%, <NUM>%, or more compared with prior to initiation of therapy, or ranges including any two of the aforementioned values.

Conventional devices that provide a hypoxic atmosphere within an enclosure can suffer from several disadvantages. Such conventional setups can be quite costly due to the volume of gas that needs to be altered. Many systems are not portable, and the ones that are (such as a tent) can be both difficult to transport as well as quite small, limiting what a user can do while using it. The user can also be prevented/restricted from leaving the enclosure, and others who do not wish to use the device are unable to enter it, thus limiting the ability for interaction between participants and non-participants, especially during extended use. If the user needs to suddenly end the therapy they need to leave the enclosure, which would take significantly longer than simply removing a patient interface, such as a cannula (some devices provide a breathing device with normoxic air for use in an emergency, but this can just further add to the cost). The use of a room would also prevent individually adjusted therapy when used with others, as everyone would be required to breathe the same gas composition. The volume of the room would also make it difficult to make any quick changes to the composition of the gas. As such, it would be advantageous to limit the hypoxic atmosphere to a user interface proximate to, or directly attachable to a user.

Devices that use a mask can be disadvantageous in some cases by their obstructive nature. Using a nasal cannula (e.g., as the only conduit to the user) instead of and without using a mask means the user can still talk, eat and drink while the device is attached, making it more viable for longer therapy sessions, as the user would not need to remove it for such tasks. The portability of the cannula can also allow the user to move the device with them as they do various activities throughout the day. These factors combined allow such devices to advantageously implement a wide range of therapy regimes. The user could have a nasal cannula attached and connected to high flow systems as disclosed herein during a majority of day to day tasks, while sleeping, and while exercising on a spot (such as with a treadmill or weight training). The cannula could also be removed and reattached fairly easily, which could be useful if the therapy regime required regularly stopping and starting the administration of the hypoxic gases. The cannula can also be far more comfortable, and does not run the risk of the user developing pressure sores. Users may also in some cases find a mask somewhat claustrophobic due to the amount of their face it covers. A cannula can also be safer than a mask in some cases, as it would not obstruct breathing if the device were to fail, and can be removed more easily if needed.

Examples of systems and methods as disclosed herein advantageously deliver high flow rates (e.g., greater than about <NUM> liters per minute in adults and/or in excess of peak inspiratory demand in some cases). Some conventional devices deliver a small dose of pure nitrogen upon inspiration that can mix with additional inspired air through the user's mouth and/or around the cannula to create the required hypoxic mixture. This method can have several disadvantages in some cases. One disadvantage is that as conventional devices deliver a fixed dose or low flow of nitrogen, the total fraction of inspired oxygen (FiO<NUM>) would change as the inspiratory flow rate changes, and would depend on the user's inspiratory tidal volume, meaning that a change in breath rate or volume would alter the composition being delivered. This could make targeting a specific FiO<NUM> or SpO<NUM> very challenging. In contrast, systems and methods as disclosed herein can deliver flow rates in excess of the user's inspiratory demand, which can advantageously provide a more consistent and controlled hypoxic composition regardless of changes in the user's breathing. At least two parameters can be used to determine oxygen delivery to the user, FiO<NUM> and FdO<NUM>. FiO<NUM> is the fraction of inspired oxygen, which is the oxygen concentration of the gas that the user is actually breathing in. FdO<NUM> is the fraction of delivered oxygen, which is the oxygen concentration of the gas flowing out of the cannula. FdO<NUM> can be directly measured by the flow therapy system, such as by measuring the oxygen concentration of the gas flowing through the system. FiO<NUM> is dependent on FdO<NUM> as well as the proportion of ambient air, if any, that is entrained when the user breathes in. While FiO<NUM> can be a preferred parameter in some cases in assessing the effect of the gas on the user, control of FdO<NUM> can allow the target FiO<NUM> be achieved, for example, due to the assumption that those two parameters have the same or substantially the same value in a high flow therapy system. During a high flow therapy session, the oxygen concentration measured in the system, FdO<NUM>, can be substantially the same as the oxygen concentration the user is breathing, FiO<NUM>, when the flow rate of gas delivered meets or exceeds the peak inspiratory demand of the user. That is, the volume of gas delivered by the system to the user during inspiration meets, or is in excess of, the volume of gas inspired by the user during inspiration. In that situation, no ambient air is entrained (e.g., around a non-sealed nasal cannula) and hence the value of FdO<NUM> is equal to the value of FiO<NUM>. Accordingly, high flow therapies can help to prevent entrainment of ambient air when the user breathes in, as well as to flush the user's airways of expired gas. Further, systems and methods as disclosed herein can also provide a closed loop control to provide hypoxic composition, such as based on monitoring of the user's oxygen saturation, SpO<NUM>, when the flow rate is not meeting the user's inspiratory demand such that FdO<NUM> is not equal to FiO<NUM> due to entrainment of ambient air.

While nitrogen is a common hypoxic gas that can be utilized in creating a hypoxic gas mixture, the use of other hypoxic gases are possible in addition to, or instead of nitrogen. In some examples, the hypoxic gas composition can include, or consist entirely of or substantially entirely of physiologically inert gases. Some examples include, but are not limited to nitrogen, heliox, nitric oxide, carbon dioxide, argon, helium, methane, sulfur hexafluoride, and combinations thereof.

In some cases, systems and methods as disclosed herein can advantageously not require or perform any detection of when the user breathes in, as a fixed flow rate of gas can be delivered at all times. Systems and methods can also provide a safe, predictable, precise, hypoxic gas composition that avoids the risk of pooling large quantities of nitrogen, such as in situations where the user temporarily breathes through their mouth or the breath synchronization is not used.

Conventional systems can also suffer from the disadvantage of at best only being able to control the composition of gas up to the user's face. The actual composition of gas in the airways of the user would vary based on respiratory volume, respiratory rate, gas exchange rates of the lung, among other factors. Due to the high flow of gas being delivered by some examples as disclosed herein, the user's airways can be constantly flushed of old expired gas, so when the user inspires, the gas in user's upper airways would match that being delivered from the device or system, regardless of the aforementioned factors. Nasal high-flow gas delivery systems have been disclosed to enhance oxygen delivery to patients, but not to provide the opposite effect of delivering a hypoxic gas composition for various indications.

In some configurations, the use of a nasal system (with or without high flow delivery) to deliver warm and/or humidified hypoxic gas compositions could be beneficial in recovery from physical activity. One current criticism of altitude training is that the hypoxic conditions lead to lower intensity during training and poorer recovery after training, and that these factors have the potential to counteract out the benefits of the body's acclimatization to altitude. By combining the hot and/or humidified gas delivery of the nasal high flow system with an altitude training program, a user could potentially gain the benefits of natural acclimatization with reduced negative side effects that would otherwise impede performance and reduce overall benefits. In some cases, heated and/or humidified air can prevent or treat infections by various pathogens as discussed elsewhere herein, including via raising the temperature, or creating enough heat energy in the nasal passage, to kill some or all of the pathogens.

A schematic representation of a respiratory system or flow therapy apparatus <NUM> is provided in <FIG>. The apparatus <NUM> can include a main housing <NUM>. The main housing <NUM> can contain a flow generator <NUM> that can be in the form of a motor/impeller arrangement, an optional humidifier or humidification chamber <NUM>, a controller <NUM>, and a user interface <NUM>. The apparatus <NUM> can include any suitable gas flow generation element. The gas flow generation element can be used to generate a flow of gas and can include one or more flow generators and/or sources of pressurized gas. Examples of flow generators can include a blower or a compressor. Examples of sources of pressurized gas can include a pressurized tank or a gas source in the wall. The user interface <NUM> can include a display and input device(s) such as button(s), a touch screen, a combination of a touch screen and button(s), or the like. The controller <NUM> can include a hardware processor and can be configured or programmed to control the components of the apparatus, including but not limited to operating the flow generator <NUM> to create a flow of gases (e.g., hypoxic gases) for delivery to a user, operating the humidifier <NUM> (if present) to humidify and/or heat the gases flow, receiving user input from the user interface <NUM> for reconfiguration and/or user-defined operation of the apparatus <NUM>, and outputting information (for example on the display) to the user or healthcare professional or anyone else viewing the apparatus.

With continued reference to <FIG>, a user breathing conduit <NUM> can be coupled to a gases flow outlet <NUM> in the housing <NUM> of the flow therapy apparatus <NUM>, and be coupled to a user interface <NUM>, which can be a non-sealing interface such as a nasal cannula with a manifold <NUM> and nasal prongs <NUM>. The term "non-sealing interface" as used herein can refer to an interface providing a pneumatic link between an airway of a user and a gases flow source (such as from flow generator <NUM>) that does not completely occlude the airway of the user. A non-sealed pneumatic link can comprise an occlusion of less than about <NUM>% of the airway of the user. The non-sealed pneumatic link can comprise an occlusion of less than about <NUM>% of the airway of the user. The non-sealed pneumatic link can comprise an occlusion of between about <NUM>% and about <NUM>% of the airway of the user. The airway can include one or more of a nare or mouth of the user. Additionally, or alternatively, the user breathing conduit <NUM> can be coupled to a face mask, or a tracheostomy interface. The gases flow that is generated by the flow therapy apparatus <NUM>, and which may be humidified, is delivered to the user via the inspiratory conduit <NUM> through the cannula <NUM>. The inspiratory conduit <NUM> can have a heater wire 16a to heat gases flow passing through to the user. The heater wire 16a can be under the control of the controller <NUM>. In some embodiments, the device could include a gas heating mode in which the heater wire 16a or another heating element can be utilized to heat the hypoxic gases above the temperature of gases in the user's airway, and/or provide heat energy sufficient to kill or otherwise inactivate pathogens (e.g. viruses, including human rhinoviruses, influenza, and the like; fungi; and/or bacteria) from the gases flow, and/or pathogens already in the airways or elsewhere within the user. In some embodiments, a heating element can be present within or otherwise associated with a humidifier to raise the actual temperature and/or dew point temperature of the humidified gases stream to create a heated, humidified hypoxic gas composition, as discussed further below. Killing pathogens as both a therapeutic and/or preventative measure could be beneficial especially to athletes, where illness could severely undermine any training regime or competition performance. In some configurations, the gas heating mode can raise the temperature in the user's nasal passage high enough to provide heat energy for killing some or all of the pathogens, but not to the extent that the gases are too hot and cause other discomfort, airway damage, and other adverse effects. The hypoxic gases delivered could, in some configurations, be heated to at least about <NUM>, but not more than about <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, such as about <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or ranges incorporating any two of the aforementioned values. In some configurations, the gases can be heated to between about <NUM> and about <NUM>, between about <NUM> and about <NUM>, between about <NUM> and about <NUM>, between about <NUM> and about <NUM>, between about <NUM> and about <NUM>, between about <NUM> and about <NUM>, or about <NUM>. In some configurations, the hypoxic gases are delivered at room temperature, such as between about <NUM> and about <NUM>, or other higher or lower temperatures, such as between about <NUM> and about <NUM>. The gases can also be humidified in some embodiments to prevent evaporation of moisture in the user's nasal passage and subsequently cool down too much to be effective. Humidified gases, for example, in the temperature ranges specified can in some embodiments carry enough latent heat to not only kill infections and reduce sickness times, but also act as a preventative measure, something which can be advantageous to athletes, among others. The hypoxic gases delivered could, in some configurations, have a dew point temperature of at least about <NUM>, but not more than about <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, such as about <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or ranges incorporating any two of the aforementioned values. In some configurations, the gases can have a dew point temperature of between about <NUM> and about <NUM>, between about <NUM> and about <NUM>, between about <NUM> and about <NUM>, between about <NUM> and about <NUM>, between about <NUM> and about <NUM>, between about <NUM> and about <NUM>, or about <NUM>. In some configurations, the hypoxic gases can have a dew point temperature at room temperature, such as between about <NUM> and about <NUM>, or other higher or lower temperatures, such as between about <NUM> and about <NUM>. In some embodiments, the relative humidity of the hypoxic gas flow can be, for example, about or at least about <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or more, such as <NUM>% or ranges incorporating any two of the aforementioned values. In some embodiments, the heating and/or humidification is not in an open room setup or configuration, and as such the heating and/or humidification is delivered through the discrete breathing conduit <NUM> directly connected to the user's nose and/or mouth.

The inspiratory conduit <NUM> and/or user interface <NUM> can be considered part of the flow therapy apparatus <NUM>, or alternatively peripheral to it. The flow therapy apparatus <NUM>, breathing conduit <NUM>, and user interface <NUM> together can form a flow therapy system.

General operation of a flow therapy breathing apparatus <NUM> will now be described. The controller <NUM> can control the flow generator <NUM> to generate a gases flow of a desired flow rate, one or more valves to control mixing (e.g., hypoxic mixing) of air and nitrogen or other breathable gas, and/or the humidifier <NUM>, if present, to humidify the gases flow to an appropriate temperature and/or humidity. In some embodiments, humidification can advantageously prevent the user's airways from drying out, which can be particularly advantageous during concomitant exercise due to fluid loss from sweating. The flow delivered could be at any desired flow rate. In some embodiments, the flow rate is about or at least about <NUM> liters/minute. In some embodiments, the flow rate is about, or less than about <NUM> liters/minute, such as <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> liter/minute, or ranges incorporating any two of the aforementioned values.

As will be described in greater detail below, the apparatus <NUM> can use ultrasonic or other types of sensing to monitor characteristics of the gases in the flow. For example, the characteristics of the gases flow can include gases concentration, flow rate, or the like. The apparatus <NUM> can include additional sensors that can be in communication with the hardware processor. These sensors can include a flow rate sensor, a temperature sensor, a humidity sensor, a pressure sensor, or the like. Output of the additional sensors can be used for determining the characteristics of the gases flow, such as temperature, pressure, humidity, and the like. Output of the additional sensors can be used for correcting measurement of the characteristics of the gases flow by ultrasonic sensing. The gases flow can be directed out through the inspiratory conduit <NUM> and cannula <NUM> to the user. The cannula <NUM> may instead be any other user interface, such as a full face mask, nasal mask, nasal pillows mask, tracheostomy interface, or endotracheal tube. The controller <NUM> can also control a heating element in the humidifier <NUM> and/or the heating element 16a in the inspiratory conduit <NUM> to heat the gas to a desired temperature that achieves a desired level of therapy and/or level of comfort for the user. The controller <NUM> can be programmed with or can determine a suitable target temperature of the gases flow using one or more temperature sensors.

Additional sensors 3a, 3b, 3c, <NUM>, <NUM>, such as flow, temperature, humidity, and/or pressure sensors, can be placed in various locations in the flow therapy apparatus <NUM> and/or the inspiratory conduit <NUM> and/or cannula <NUM>. The controller <NUM> can receive output from the sensors to assist it in operating the flow therapy apparatus <NUM> in a manner that provides suitable therapy. Providing suitable therapy can include meeting a user's peak inspiratory demand in some cases. The apparatus <NUM> can include a wireless data transmitter and/or receiver, or a transceiver <NUM> to enable the controller <NUM> to receive data signals <NUM> in a wireless manner from the operation sensors and/or to control the various components of the flow therapy apparatus <NUM>. Additionally, or alternatively, the data transmitter and/or receiver <NUM> may deliver data to a remote server or enable remote control of the apparatus <NUM>. The apparatus <NUM> can include a wired connection, for example, using cables or wires, to enable the controller <NUM> to receive data signals <NUM> from the operation sensors and/or to control the various components of the flow therapy apparatus <NUM>. The transmitter can connect with a mobile device, such as a phone. The display, such as a graphic user interface (GUI) can be replicated on the mobile device's screen. Once connected to the apparatus <NUM>, the mobile device can be used to control the device. The apparatus <NUM> can connect to the mobile device via a wireless connection, such as Bluetooth, WiFi, near field communication (NFC), <NUM>/<NUM>/<NUM>/<NUM>, or other suitable wireless communications networks. The apparatus <NUM> can additionally or alternatively connect via a wired connection, such as USB, Ethernet, FireWire, serial port interface, or other suitable data transmission wires.

In some embodiments, one or more sensors (e.g., ultrasonic transducers as described herein) can be utilized to measure/verify the hypoxic gas composition (e.g., oxygen concentration) after, for example, nitrogen and ambient air have finished mixing. In some embodiments, at least one sensor on at least two of the ambient air inlet conduit, the nitrogen inlet conduit, and the final delivery conduit can be utilized to determine the flow rate of at least two gases. By inputting the flow rate of both inlet gases or one inlet gas and one total flow rate, along with the assumed oxygen concentrations of the inlet gases (e.g., <NUM>% for ambient air, <NUM>% for <NUM>% pure enriched nitrogen), the oxygen concentration of the final gas composition can be calculated. As such, the hypoxic gas composition could include, for example, nitrogen enriched with between about <NUM>% and about <NUM>% oxygen (e.g., FdO<NUM>), between about <NUM>% and about <NUM>% of oxygen, between about <NUM>% and about <NUM>% of oxygen, about <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>% of oxygen, or ranges incorporating any of the aforementioned values. If inspiratory demand is met by the flow rate delivered to the user, FiO<NUM> can also be any of the aforementioned values. If inspiratory demand is not met, FiO<NUM> may be somewhat closer to the oxygen concentration in ambient air, as ambient air would be entrained around the cannula, which may reduce the nitrogen concentration in the gases inspired by the user.

In some embodiments, the hypoxic gas source itself could be made of a hypoxic gas of less than <NUM>% purity. For example, the hypoxic gas source (e.g., enriched nitrogen and/or other hypoxic gases) could be at a purity of, for example, between about <NUM>% and about <NUM>%, such as between about <NUM>% and about <NUM>%, or about <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or ranges incorporating any of the aforementioned values. The oxygen concentration of the hypoxic gas source could be in some cases between about <NUM>% and about <NUM>% oxygen, between about <NUM>% and about <NUM>% of oxygen, between about <NUM>% and about <NUM>% of oxygen, about <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>% of oxygen, or ranges incorporating any of the aforementioned values. Enriched nitrogen or another hypoxic gas at less than about <NUM>% purity, such as <NUM>% purity (with <NUM>% oxygen), for example, can be advantageous from a safety perspective in preventing the FiO<NUM> from dipping below <NUM>% (or another desired floor percentage), even in the event of a malfunction when mixing the nitrogen-enriched gas with ambient air.

In some embodiments, flow rate sensors can be placed at each location to allow for redundancy and testing that each sensor is working correctly by checking for consistency of readings. Any combination of the above methods, for example, could be implemented together to further allow for checking of consistency of results, along with failsafes if one or more sensors are not working correctly. Further sensors could be included (such as temperature and ambient pressure sensors) as disclosed herein to allow for correction of flow rate and/or gas concentration readings based on other factors.

Still referring to <FIG>, one, two, or more physiological sensors <NUM> can communicate with the data transmitter and/or receiver <NUM> to communicate data regarding physiological information of the user. The sensors <NUM> could be, for example, a pulse oximeter for measuring the oxygen saturation of a user's arterial blood, a heart rate sensor, blood pressure sensor, respiratory rate sensor, tidal volume sensor, ECG, heart rate variability sensor, and the like. Data received from the sensors <NUM> can also communicate with the controller <NUM> to be displayed on the user interface <NUM>. Data from the sensors <NUM> can also be used by the controller <NUM> to provide closed loop feedback to modify various parameters of the device including oxygen concentration of the hypoxic gas concentration, flow rate, humidity, temperature, and the like as described in detail elsewhere herein.

The flow therapy apparatus may be any suitable type of apparatus, but in some configurations may deliver a high gases flow or high flow therapy (of e.g., air, nitrogen, a hypoxic gas mixture, or some combination thereof) to a user for altitude training, enhanced athletic performance, or other indications such as those discussed elsewhere herein. The gas can be or comprise nitrogen. The gas can comprise ambient air. The gas can comprise a blend of nitrogen and ambient air to create hypoxic gas compositions as noted elsewhere herein. The gas source could be a less than <NUM>% pure enriched hypoxic gas such as a hypoxic mix of nitrogen and oxygen that is mixed with ambient air in the system that can be advantageous from a safety perspective in some cases as mentioned elsewhere herein. "High flow therapy" as used in this disclosure may refer to delivery of gases to a user at a flow rate of greater than or equal to about <NUM> liters/minute (<NUM> LPM). In some configurations, "high flow" therapy refers to administration of gas to the airways of a patient at a relatively high flow rate. In some configurations, the relatively high flow rate meets or exceeds the peak inspiratory demand of the user. In other configurations, the high flow rate may not meet or exceed the peak inspiratory demand of the user. The flow rates used to achieve "high flow" may be any of the flow rates listed below. For example, in some configurations, for an adult patient "high flow therapy" may refer to the delivery of gases to a user at a flow rate of greater than or equal to about <NUM> litres per minute (<NUM> LPM), such as between about <NUM> LPM and about <NUM> LPM, or between about <NUM> LPM and about <NUM> LPM, or between about <NUM> LPM and about <NUM> LPM, or between about <NUM> LPM and about <NUM> LPM, or between about <NUM> LPM and about <NUM> LPM, or between about <NUM> LPM and about <NUM> LPM, or between about <NUM> LPM and about <NUM> LPM, or between about <NUM> LPM and about <NUM> LPM, or between about <NUM> LPM and about <NUM> LPM. Gases delivered may comprise a percentage of nitrogen and oxygen. In some configurations, such as when the system is implementing a closed loop control algorithm as disclosed herein, delivery of hypoxic gases may not be limited to a high flow therapy and/or the inspiratory demand of the user may or may not be met by the flow rate.

In some embodiments, the device or system can allow for the user to change the flow rate during use, such as through interaction with a control, e.g., a user interface on the device. The flow rate may be varied, for example, by the controller varying the speed of the blower. This could be beneficial as the device could be used in different scenarios that require different flow rates. In some cases, flow rate could also oscillate in synchrony with breathing as long as a peak inspiratory demand of the user is being met. For example, if the user was to use the device while exercising then they could have an increased minute ventilation by way of an increased respiratory rate and/or increased tidal volume, so the flow rate could optionally be raised compared with when using the device at rest in order to meet increased peak inspiratory demand. In some embodiments, the device can allow for the user to change the oxygen concentration of the gases delivered via a control that modulates the flow of a hypoxic gas other than air, such as enriched nitrogen, from a hypoxic gas source into a conduit directly connected to the user, such as the nasal cannula.

The percentage of oxygen in the gases delivered may be, in embodiments where hypoxia is desired, such that the percentage of oxygen in the gas composition delivered to the user is less than that of typical room air (e.g., less than about <NUM>%). In some embodiments, the percentage of oxygen in the gas composition is between about <NUM>% and about <NUM>%, or between about <NUM>% and about <NUM>%, or between about <NUM>% and about <NUM>%, or between about <NUM>% and about <NUM>%, or between about <NUM>% and about <NUM>%, or between about <NUM>% and about <NUM>%, or about or no more than about <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or <NUM>%, or any ranges incorporating two of the aforementioned values. The percentage of oxygen in the inspired gas would be the same or greater than the aforementioned values, depending on whether inspiratory demand is met. In some embodiments, the percentage of nitrogen in the hypoxic gas composition is about or at least about <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or more, or any ranges incorporating two of the aforementioned values. The percentage of nitrogen in the inspired gas would be the same or less than the aforementioned values, depending on whether inspiratory demand is met. In some embodiments, the percentage of inspired or delivered nitrogen, oxygen, and/or other gases could be any of the preceding values or ranges, or others as disclosed elsewhere herein.

High flow hypoxic gas therapy can be effective in meeting or exceeding the user's peak inspiratory demand, delivering nitrogen enriched air (and therefore O<NUM> diminished air) and using a nasal high flow system configured for a variety of medical and non-medical applications, including but not limited to simulated altitude training, enhanced athletic performance, or other indications. Not to be limited by theory, in some embodiments systems and methods as disclosed herein could be used to treat or prevent hypertension, obesity, hyperlipidemia, prediabetes or impaired glucose tolerance, diabetes mellitus type I or type II, metabolic syndrome, mitochondrial regeneration, aging, fatigue, inflammatory diseases, anemia, or other conditions. Additionally, high flow therapy may generate a flushing effect in the nasopharynx such that the anatomical dead space of the upper airways is flushed completely or substantially completely by the high incoming gases flow. This can create a reservoir of fresh gas available of each and every breath of the exact desired composition (e.g., hypoxic composition), and prevent entrainment of ambient air that would alter the composition of the gas as well as minimizing re-breathing of carbon dioxide. These aforementioned features can work together to give increased consistency and control of the hypoxic solution that the user breathes, regardless of factors such as breath rate and volume.

The user interface may be in some embodiments a non-sealing interface, which advantageously prevents barotrauma (e.g. tissue damage to the lungs or other organs of the respiratory system due to difference in pressure relative to the atmosphere). The user interface may be a nasal cannula with a manifold and nasal prongs, and/or a face mask, and/or a nasal pillows mask, and/or a nasal mask, and/or a tracheostomy interface, or any other suitable type of user interface.

Some examples of the flow therapy apparatus are described herein. <FIG> show an example flow therapy apparatus <NUM> having a main housing <NUM>. The main housing <NUM> has a main housing upper chassis <NUM> and a main housing lower chassis <NUM>.

The main housing upper chassis <NUM> has a peripheral wall arrangement <NUM> (see <FIG>). The peripheral wall arrangement defines a humidifier or humidification chamber bay <NUM> for receipt of a removable humidification chamber <NUM>. The removable humidification chamber <NUM> contains a suitable liquid such as water for humidifying gases that can be delivered to a user.

In the form shown, the peripheral wall arrangement <NUM> of the main housing upper chassis <NUM> can include a substantially vertical left side outer wall <NUM> that is oriented in a front-to-rear direction of the main housing <NUM>, a substantially vertical left side inner wall <NUM> that is oriented in a front-to-rear direction of the main housing <NUM>, and an interconnecting wall <NUM> that extends between and interconnects the upper ends of the left side inner and outer walls <NUM>, <NUM>. The main housing upper chassis <NUM> can further include a substantially vertical right side outer wall <NUM> that is oriented in a front-to-rear direction of the main housing <NUM>, a substantially vertical right side inner wall <NUM> that is oriented in a front-to-rear direction of the main housing <NUM>, and an interconnecting wall <NUM> that extends between and interconnects the upper ends of the right side inner and outer walls <NUM>, <NUM>. The interconnecting walls <NUM>, <NUM> are angled towards respective outer edges of the main housing <NUM>, but can alternatively be substantially horizontal or inwardly angled.

The main housing upper chassis <NUM> can further include a substantially vertical rear outer wall <NUM>. An upper part of the main housing upper chassis <NUM> can include a forwardly angled surface <NUM>. The surface <NUM> can have a recess <NUM> for receipt of a display and user interface module <NUM>. The display can be configured to display characteristics of sensed gas(es) in real time, such as the oxygen concentration, temperature, humidity, and/or other characteristics. In some embodiments, the oxygen concentration could be displayed as an altitude above sea level (e.g., in meters or feet) that would result in an equivalent partial pressure of oxygen. Conversions between FiO<NUM> and equivalent altitude could be done by the device by assuming an ambient oxygen concentration of, for example, about <NUM>%. An interconnecting wall <NUM> can extend between and interconnect the upper end of the rear outer wall <NUM> and the rear edge of the surface <NUM>.

A substantially vertical wall portion <NUM> can extend downwardly from a front end of the surface <NUM>. A substantially horizontal wall portion <NUM> can extend forwardly from a lower end of the wall portion <NUM> to form a ledge. A substantially vertical wall portion <NUM> can extend downwardly from a front end of the wall portion <NUM> and terminate at a substantially horizontal floor portion <NUM> of the humidification chamber bay <NUM>. The left side inner wall <NUM>, right side inner wall <NUM>, wall portion <NUM>, and floor portion <NUM> together can define the humidification chamber bay <NUM>. The floor portion <NUM> of the humidification chamber bay <NUM> can have a recess <NUM> to receive a heater arrangement such as a heater plate <NUM> or other suitable heating element(s) for heating liquid in the humidification chamber <NUM> for use during a humidification process.

The main housing lower chassis <NUM> can be attachable to the upper chassis <NUM>, either by suitable fasteners or integrated attachment features such as clips for example. The main housing lower chassis <NUM> can include a substantially vertical left side outer wall <NUM> that is oriented in a front-to-rear direction of the main housing <NUM> and is contiguous with the left side outer wall <NUM> of the upper chassis <NUM>, and a substantially vertical right side outer wall <NUM> that is oriented in a front-to-rear direction of the main housing <NUM> and is contiguous with the right side outer wall <NUM> of the upper chassis <NUM>. The main housing lower chassis <NUM> can further include a substantially vertical rear outer wall <NUM> that is contiguous with the rear outer wall <NUM> of the upper chassis <NUM>.

The lower housing chassis <NUM> can have a lip <NUM> that is contiguous with the lip <NUM> of the upper housing chassis <NUM>, and also forms part of the recess for receiving the handle portion <NUM> of the lever <NUM>. The lower lip <NUM> can include a forwardly directed protrusion <NUM> that acts as a retainer for the handle portion <NUM> of the lever <NUM>.

An underside of the lower housing chassis <NUM> can include a bottom wall <NUM>. Respective interconnecting walls <NUM>, <NUM>, <NUM> can extend between and interconnect the substantially vertical walls <NUM>, <NUM>, <NUM> and the bottom wall <NUM>. The bottom wall <NUM> can include a grill <NUM> comprising a plurality of apertures to enable drainage of liquid in case of leakage from the humidification chamber <NUM> (e.g. from spills). The bottom wall <NUM> additionally can include elongated forward-rearward oriented slots <NUM>. The slots <NUM> can additionally enable drainage of liquid in case of leakage from the humidification chamber <NUM>, without the liquid entering the electronics housing. In the illustrated configuration, the slots <NUM> can be wide and elongate relative to the apertures of the grill <NUM> to maximize the drainage of liquid.

As shown in <FIG>, the lower chassis <NUM> can have a motor recess <NUM> for receipt of a motor/sensor module. The motor/sensor module may be non-removable from the main housing <NUM>. The motor/sensor module may be removable from the main housing <NUM>, as illustrated in <FIG>. A recess opening <NUM> can be provided in the bottom wall <NUM> adjacent a rear edge thereof, for receipt of a removable motor/sensor module. A continuous, gas impermeable, unbroken peripheral wall <NUM> can be integrally formed with the bottom wall <NUM> of the lower chassis <NUM> and extend upwardly from the periphery of the opening <NUM>. A rearward portion <NUM> of the peripheral wall <NUM> has a first height, and a forward portion <NUM> of the peripheral wall <NUM> has a second height that is greater than the first height. The rearward portion <NUM> of the peripheral wall <NUM> terminates at a substantially horizontal step <NUM>, which in turn terminates at an upper auxiliary rearward portion <NUM> of the peripheral wall <NUM>. The forward portion <NUM> and upper auxiliary rearward portion <NUM> of the peripheral wall <NUM> terminate at a ceiling <NUM>. All of the walls and the ceiling <NUM> can be continuous, gas impermeable, and unbroken other than the gases flow passage. Therefore, the entire motor recess <NUM> can be gas impermeable and unbroken, other than the gases flow passage.

The motor/sensor module may be insertable into the recess <NUM> and attachable to the lower chassis <NUM>. Upon insertion of the motor/sensor module into the lower chassis <NUM>, the gases flow passage tube <NUM> can extend through the downward extension tube <NUM> and be sealed by the soft seal.

The humidification chamber <NUM> can be fluidly coupled to the apparatus <NUM> in a linear slide-on motion in a rearward direction of the humidification chamber <NUM> into the chamber bay <NUM>, from a position at the front of the housing <NUM> in a direction toward the rear of the housing <NUM>. A gases outlet port <NUM> can be in fluid communication with the motor.

A gases inlet port <NUM> (humidified gases return) as shown in <FIG> can include a removable L-shaped elbow. The removable elbow can further include a user outlet port <NUM> for coupling to the inspiratory conduit <NUM> to deliver gases to the user interface <NUM>. The gases outlet port <NUM>, gases inlet port <NUM>, and user outlet port <NUM> each can have soft seals such as O-ring seals or T-seals to provide a sealed gases passageway between the apparatus <NUM>, the humidification chamber <NUM>, and the inspiratory conduit <NUM>.

The humidification chamber gases inlet port <NUM> can be complementary with the gases outlet port <NUM>, and the humidification chamber gases outlet port <NUM> can be complementary with the gases inlet port <NUM>. The axes of those ports can be parallel to each other to enable the humidification chamber <NUM> to be inserted into the chamber bay <NUM> in a linear movement.

The apparatus <NUM> can have air and nitrogen (or alternative auxiliary gas) inlets in fluid communication with the motor to enable the motor to deliver air, nitrogen-enhanced air to form a hypoxic mixture, or a suitable mixture thereof to the humidification chamber <NUM> and thereby to the user. As shown in <FIG>, the apparatus <NUM> may have a combined air/nitrogen (or alternative auxiliary gas) inlet arrangement <NUM>. This arrangement can include a combined air/nitrogen port <NUM> into the housing <NUM>, a filter <NUM>, and a cover <NUM> with a hinge <NUM>. In other embodiments, a gases tube can extend laterally or in another appropriate direction and be in fluid communication with a nitrogen source. The port <NUM> can be fluidly coupled with the motor <NUM>. For example, the port <NUM> may be coupled with the motor/sensor module <NUM> via a gases flow passage between the port <NUM> and an inlet aperture or port in the motor/sensor module <NUM>, which in turn would lead to the motor.

The apparatus <NUM> may have the arrangement shown in <FIG> to enable the motor to deliver air, nitrogen (or alternative auxiliary gas), or a suitable mixture thereof to the humidification chamber <NUM> and thereby to the user. This arrangement can include an air inlet <NUM>' in the rear wall <NUM> of the lower chassis <NUM> of the housing <NUM>. The air inlet <NUM>' comprises a rigid plate with a suitable grill arrangement of apertures and/or slots. Sound dampening foam may be provided adjacent the plate on the interior side of the plate. An air filter box <NUM>' can be positioned adjacent the air inlet <NUM>' internally in the main housing <NUM>, and include an air outlet port <NUM> to deliver filtered air to the motor via an air inlet port <NUM> in the motor/sensor module <NUM>. The air filter box <NUM>' may include a filter configured to remove particulates (e.g. dust) and/or pathogens (e.g. viruses, fungi, or bacteria) from the gases flow. A soft seal such as an O-ring seal can be provided between the air outlet port <NUM> and air inlet port <NUM> to seal between the components. The apparatus <NUM> can include a separate nitrogen inlet port <NUM>' positioned adjacent one side of the housing <NUM> at a rear end thereof, the nitrogen port <NUM>' for receipt of nitrogen from a nitrogen source such as a tank or source of piped nitrogen. The nitrogen inlet port <NUM>' can optionally be in fluid communication with a valve <NUM>. The valve <NUM> can suitably be a solenoid valve that enables the control of the amount of nitrogen that is added to the gases flow that is delivered to the humidification chamber <NUM>. The nitrogen port <NUM>' and valve <NUM> may be used with other (e.g., other than nitrogen) auxiliary gases to control the addition of other auxiliary gases to the gases flow. The other auxiliary gases may include any one or more of a number of gases useful for gas therapy, including but not limited to heliox, oxygen, nitrogen, nitric oxide, carbon dioxide, argon, helium, methane, sulfur hexafluoride, and combinations thereof. In some embodiments a valve need not be present, and nitrogen flow can be manually controlled at the nitrogen source. The oxygen concentration of the hypoxic gases flow can be read from the user interface, and the amount of nitrogen titrated at the nitrogen source accordingly depending on the desired result.

As shown in <FIG>, the lower housing chassis <NUM> can include suitable electronics boards <NUM>, such as sensing circuit boards. The electronics boards can be positioned adjacent respective outer side walls <NUM>, <NUM> of the lower housing chassis <NUM>. The electronics boards <NUM> can contain, or can be in electrical communication with, suitable electrical or electronics components, such as but not limited to microprocessors, capacitors, resistors, diodes, operational amplifiers, comparators, and switches. Sensors may be used with the electronic boards <NUM>. Components of the electronics boards <NUM> (such as but not limited to one or more microprocessors) can act as the controller <NUM> of the apparatus.

One or both of the electronics boards <NUM> can be in electrical communication with the electrical components of the apparatus <NUM>, including the display unit and user interface <NUM>, motor, valve <NUM>, and the heater plate <NUM> to operate the motor to provide the desired flow rate of gases, operate the humidifier <NUM> to humidify and heat the gases flow to an appropriate level, and supply appropriate quantities of nitrogen (or quantities of an alternative auxiliary gas) to the gases flow.

The electronics boards <NUM> can be in electrical communication with a connector arrangement <NUM> projecting from the rear wall <NUM> of the upper housing chassis <NUM>. The connector arrangement <NUM> may be coupled to an audible, visual, tactile, or other alarm, pulse oximetry port, and/or other suitable accessories. The electronics boards <NUM> can also be in electrical communication with an electrical connector <NUM> that can also be provided in the rear wall <NUM> of the upper housing chassis <NUM> to provide mains or battery power to the components of the apparatus <NUM>.

As mentioned above, operation sensors, such as flow, temperature, humidity, and/or pressure sensors can be placed in various locations in the flow therapy apparatus <NUM> and/or the inspiratory conduit <NUM> and/or cannula <NUM>. The electronics boards <NUM> can be in electrical communication with those sensors. Output from the sensors can be received by the controller <NUM>, to assist the controller <NUM> to operate the flow therapy apparatus <NUM> in a manner that provides optimal therapy, including optionally meeting peak inspiratory demand.

As outlined above, the electronics boards <NUM> and other electrical and electronic components can be pneumatically isolated from the gases flow path to improve safety. The sealing also prevents water ingress.

<FIG> illustrate another flow therapy apparatus <NUM> including a main housing having a main housing upper chassis <NUM> and a main housing lower chassis <NUM>. The flow therapy apparatus <NUM> can further include a humidification chamber bay <NUM> for receipt of a removable humidification chamber. The flow therapy apparatus <NUM> may have any of the features and/or functionality described herein in relation to the flow therapy apparatus <NUM>, but those features are not repeated here for simplicity. Similarly, the features and/or functionality of the flow therapy apparatus <NUM> may be used in the other apparatus described herein.

The flow therapy apparatus <NUM> can have a single-sided handle/lever <NUM>. That is, only one side of the handle/lever <NUM> is movably connected relative to the main housing of the flow therapy apparatus <NUM>, whereas there is no pivot connection of the other side of the handle/lever <NUM> to the main housing. As shown in <FIG>, a left side of the handle/lever <NUM> is pivotally connected relative to the main housing. However, it is possible to have only the right side pivotally connected to the main housing. The handle/lever <NUM> is pivotally and translationally connected to the main housing, so that the handle/lever <NUM> moves on a path having a varying radius relative to the main housing.

A terminal part of the handle/lever <NUM> can have a cross-member handle portion <NUM> that interconnects forward ends of a left side arm <NUM> and a right side member <NUM> and forms an engagement region for grasping by a user's fingers. When the handle <NUM> is in the raised position as shown in <FIG> for example, the cross-member <NUM> can act as a carrying handle for the flow therapy apparatus <NUM>. When the handle is in the fully raised position, the cross member <NUM> can be positioned generally above and generally in line with the centre of gravity of the flow therapy apparatus <NUM> (including the liquid chamber). The liquid chamber can be inserted into or removed from the humidification chamber bay <NUM> when the handle/lever <NUM> is raised. When the handle/lever <NUM> is in the lowered position, it can inhibit or prevent removal of the liquid chamber from the humidification chamber bay <NUM>.

<FIG> illustrates the flow therapy apparatus <NUM> without the handle/lever. As shown in <FIG>, a removable gases flow tube in the form of a removable elbow <NUM> can be used in the flow therapy apparatus <NUM>. The elbow <NUM> can receive humidified gases from the liquid chamber at an inlet port <NUM> and direct the humidified gases to an outlet port <NUM> toward the user interface through the user breathing conduit.

Similar to the flow therapy apparatus <NUM>, the lower chassis <NUM> of the flow therapy apparatus <NUM> can have a motor recess for receiving a motor/sensor module. The motor/sensor module can include a blower, which entrains room air to deliver to a user. The gases can be mixed prior to entering the sensor module. The blower can be a mixer for mixing the gases before the gases enter a sensing chamber of the sensor module. The apparatus can include an integrated or separate gas mixer in some cases. The separate gas mixer can be positioned before or after the blower. Nitrogen can be entrained after the blower and the separate gas mixer can be used to mix the nitrogen and air following entrainment. The controller can increase or decrease a flow rate of the gases flowing through the flow therapy apparatus by controlling a motor speed of the blower.

<FIG> illustrates a block diagram <NUM> of an example control system <NUM> that can detect user conditions and control operation of the flow therapy apparatus including the gas source. The control system <NUM> can manage a flow rate of the gas flowing through the flow therapy apparatus as it is delivered to a user. For example, the control system <NUM> can increase or decrease the flow rate by controlling an output of a motor speed of the blower (hereinafter also referred to as a "blower motor") <NUM> or an output of a valve <NUM> in a blender. The control system <NUM> can automatically determine a set value or a personalized value of the flow rate for a particular user as discussed below. The flow rate can be optimized by the control system <NUM> to improve user comfort and therapy.

The control system <NUM> can also generate audio and/or display/visual outputs <NUM>, <NUM>. For example, the flow therapy apparatus can include a display and/or a speaker. The display can indicate to the user, physician, trainer, or other party any warnings or alarms generated by the control system <NUM>. The display can also indicate control parameters that can be adjusted by the user or other individual. For example, the control system <NUM> can automatically recommend a flow rate for a particular user. The control system <NUM> can also determine a respiratory state of the user, including but not limited to generating a respiratory rate of the user, and send it to the display.

In some embodiments, a physiological parameter, such as SpO<NUM> of a user for example, could additionally or alternatively be fed into an alarm system. The alarm system could monitor the user's SpO<NUM>, and have set responses if it were to fall below a certain level. The device could additionally or alternatively have alarms for FiO<NUM> values, assuming that the user's inspiratory demand is met, and that FdO<NUM> is equal to FiO<NUM>. As described above, if the user's inspiratory demand is not met, the actual FiO<NUM> value would be higher than the assumed value. The alarms would be on the basis of the measured oxygen concentration in the unit, which is FdO<NUM>. The device would alarm on the basis of FdO<NUM> and assume that the parameter being measured is FiO<NUM>. This could affect therapy, but not affect safety. Responses from the system could include visual and/or audible alarms, reducing the nitrogen being supplied, setting the nitrogen flow to a predetermined value, setting the nitrogen flow to achieve a specific FiO<NUM> or SpO<NUM>, completely shutting off the nitrogen supply, shutting off all flow completely or any combination of these responses.

The system could have multiple thresholds, where different responses or sets of responses are triggered at different SpO<NUM> and/or FiO<NUM> readings. As subsequent thresholds are crossed, different responses could occur in place of the previous responses, in addition to the previous responses, and/or act as a variation of a previous response (e.g. an audible alarm changes in volume or tone).

In some embodiments, the device could alarm for at least the FiO<NUM> when controlling SpO<NUM>, and vice versa, as this could mean the user is prevented from reaching dangerous levels of both SpO<NUM> and FiO<NUM>, as one is bound by the control limits of the device and the other is bound by alarm limits. It would also have added safety through redundancy in the event of a faulty reading of one of the SpO<NUM> or FiO<NUM> sensors.

Alarm thresholds could include time factors. These would allow for the device to not be triggered by brief false readings, such as requiring a threshold to be about or at least about <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or more seconds for example. They could also allow for escalation in response of the device based on length of time at a certain value (for example, going from a visual to audible alarm, or a louder or more prominent alarm). They could also allow for alarms to be set off after a set amount of time (for example, alarming at SpO<NUM> readings that are safe for a short exposure but become dangerous after a longer duration of exposure, such as, for example, at about or at least about <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> seconds, or more).

Some non-limiting examples of values at which an SpO<NUM> reading could trigger an alarm could include below about <NUM>% (as this is the lower limit of what is considered a healthy SpO<NUM> reading at sea level), and/or below about <NUM>% (as this is typically the value below which negative side effects begin to occur), and/or below about <NUM>% (as this is the value that is typically regarded as the point where altitude training becomes dangerous), and/or below about <NUM>% (as this is the point where therapy should be stopped immediately), and/or below about <NUM>% (as this is the point where the user would likely have impaired mental function and judgement), and/or below about <NUM>% (as this is the point where the user would likely lose consciousness).

Some values at which FiO<NUM>/equivalent altitude readings could trigger a response from the system could include about <NUM>% (that is, about <NUM>) as this is typically the upper altitude limit of an extended exposure therapy program, and/or about <NUM>% (that is, about <NUM>) as this is typically the upper altitude limit of any therapy program, and/or about <NUM>% (that is, about <NUM>) as this is the limit of what is typically considered safe without medical supervision, and/or about <NUM>% (that is, about <NUM>) as this represents the highest recorded permanently tolerable altitude, and/or about <NUM>% (that is, about <NUM>) as this is commonly referred to as the "death zone" where the oxygen concentration is insufficient to sustain human life.

The device could additionally or alternatively have one or more alarm limits for SpO<NUM> and/or FiO<NUM> that change in response to one or more inputs. The one or more inputs could include an FiO<NUM> reading, an SpO<NUM> reading, a heart rate measurement, a respiratory rate measurement, an input by the user of their desired therapy program, a sensed or user input indication that the user is exercising, an amount of time the user has been using the device, and/or one or more user characteristics (this could include age, height, weight, gender, activity/fitness level, experience with altitude training). The indication of user exercise in particular could come from one or a combination of the other inputs listed, and could be transmitted as qualitative signal (e.g., either exercising or not exercising) or as a quantitative signal (e.g., exercise intensity level).

The relationship between one or more alarm limits and one or more inputs could be one that changes dynamically (e.g., as age increases the alarm trigger threshold for FiO<NUM> steadily increases). Additionally, or alternatively, one or more alarm limits could change by a set amount in response to one or more inputs. The change in one or more limits could occur at one or more thresholds of a quantitative signal (e.g., the alarm threshold for SpO<NUM> increases by a certain amount after a specific amount of time that user has been using the device) and/or in response to a qualitative signal (e.g., the FiO<NUM> alarm threshold jumps to a higher value when the user indicates that they are beginning exercise).

Having alarm limits that vary on a range of conditions can allow the user to safely employ a training regime that allows them to reach their maximum potential. While alarm limits can be applied in a blanket "one fit all" approach in some embodiments, this may not be desirable in some implementations because in order for the system to be safe for all or most users in all or most scenarios the device may become overly safe (or not challenging enough) for others, to the point where certain users are not able to gain maximum benefit from the device. The system would also be able to provide alarms for readings, particularly SpO<NUM> readings, that while potentially safe are abnormal given the current parameters provided. For example, if a user had an SpO<NUM> reading of less than <NUM>% while at rest and breathing normoxic gas, then the device could alarm to tell the user that his or her resting SpO<NUM> is abnormally low, and the user should consult a medical professional before commencing with an altitude training program.

In some embodiments, any alarms that are capable of changing based off various inputs would be coupled with one or more fixed alarms (such as the ones listed above) that provide absolute limits regardless of any input.

A similar methodology to the above could be additionally or alternatively applied in a similar way to the ranges for FiO<NUM> and/or SpO<NUM> that the user can attempt to control to. As above, this could allow the user to use the device in a way that is individually tailored to be both optimally effective and safe based on the parameters provided. It could allow for access to a greater range of training levels while avoiding potentially dangerous misuse by the user. Optionally, a fixed upper limit for the device could be coupled with a variable lower limit, or vice versa. The device could have one or more variable limits paired with a fixed limit that the variable limit could not exceed.

Table <NUM> below lists various non-limiting flow rates of nitrogen to illustrate what would roughly be required to achieve various oxygen concentrations. Preferably a value for total flow would be selected, and this would remain constant regardless of changes to nitrogen flow rate and/or FiO<NUM>, unless a new total flow rate is selected. If the total flow rate in the device is adjusted, a proportional change in the nitrogen flow rate would be required to maintain the same FiO<NUM>.

The control system <NUM> can change heater control outputs to control one or more of the heating elements (for example, to maintain a temperature set point of the gas delivered to the user). The control system <NUM> can also change the operation or duty cycle of the heating elements. The heater control outputs can include heater plate control output(s) <NUM> and heated breathing tube control output(s) <NUM>.

The control system <NUM> can determine the outputs <NUM>-<NUM> based on one or more received inputs <NUM>-<NUM>. The inputs <NUM>-<NUM> can correspond to sensor measurements received automatically by the controller <NUM> (shown in <FIG>). The control system <NUM> can receive sensor inputs including but not limited to temperature sensor(s) inputs <NUM>, flow rate sensor(s) inputs <NUM>, motor speed inputs <NUM>, pressure sensor(s) inputs <NUM>, gas(s) fraction sensor(s) inputs <NUM>, humidity sensor(s) inputs <NUM>, pulse oximeter (for example, SpO<NUM>) sensor(s) inputs <NUM>, stored or user parameter(s) <NUM>, duty cycle or pulse width modulation (PWM) inputs <NUM>, voltage(s) inputs <NUM>, current(s) inputs <NUM>, acoustic sensor(s) inputs <NUM>, power(s) inputs <NUM>, resistance(s) inputs <NUM>, CO<NUM> sensor(s) inputs <NUM>, and/or spirometer inputs <NUM>. The control system <NUM> can receive inputs from the user or stored parameter values in a memory <NUM> (shown in <FIG>). The control system <NUM> can dynamically adjust flow rate for a user over the time of their therapy. The control system <NUM> can continuously detect system parameters and user parameters. A person of ordinary skill in the art will appreciate based on the disclosure herein that any other suitable inputs and/or outputs can be used with the control system <NUM>.

In some embodiments, a target oxygen concentration could be selected, and the difference between this and the measured oxygen concentration could be fed into a controller for the valve, which would open and close to alter the supply of nitrogen until the measured oxygen concentration matches the target oxygen concentration. In some embodiments, the target oxygen concentration and/or the measured oxygen concentration could be displayed on the device and/or an ancillary device, such as the user's smartphone, smartwatch, or the like. Alternatively, the device could control to the user's blood oxygen saturation (SpO<NUM>) instead of inspired oxygen concentration (FiO<NUM>). This could utilize at least one sensor (such as a pulse oximeter) to measure SpO<NUM> at a point on the user's body (for example, their finger). This reading could then be displayed somewhere, potentially on the device or the sensor. The user, or the control system could then alter the FiO<NUM> being delivered using any of the above methods to reach a target SpO<NUM>. In some setups, the FiO<NUM> or equivalent altitude could be displayed. Additionally, the display could display the altitude equivalent of the current FiO<NUM>. The user may be able to change the target altitude via controls on the display or elsewhere. This target altitude would be converted to a target FiO<NUM> value by the device controller, which can be used to control the valve. The ability of allowing users to vary the altitude would be desirable for a user who wishes to simulate specific altitudes, instead of targeting specific FiO<NUM> values.

With reference to <FIG>, a schematic diagram of the closed loop control system is illustrated. The closed loop control system may utilize two control loops. The first control loop may be implemented by the SpO<NUM> controller. The SpO<NUM> controller can determine a target oxygen concentration, such as FdO<NUM>. Where the gases flow is being delivered as nasal high flow through a non-sealed cannula, assuming the user's inspiratory demand is met, FdO<NUM> would be substantially equivalent to FiO<NUM>. The determined target oxygen concentration is based at least in part on the target SpO<NUM> and/or the measured SpO<NUM>. The target SpO<NUM> value can be a single value or a range of acceptable values. The value(s) could be pre-set, chosen by a user, or determined automatically based on user characteristics. Generally, target SpO<NUM> values are received or determined before or at the beginning of a therapy session, though target SpO<NUM> values may be received at any time during the therapy session. During a therapy session, the SpO<NUM> controller can also receive as inputs: measured FdO<NUM> reading(s) from a gases composition sensor, and measured SpO<NUM> reading(s) and a signal quality reading(s) from the physiological sensor. In some configurations, the SpO<NUM> controller can receive target FdO<NUM> as an input. In such a case, the output of the SpO<NUM> controller may be provided directly back to the SpO<NUM> controller as the input. Based at least in part on the inputs, the SpO<NUM> controller can output a target FdO<NUM> to the second control loop.

The second control loop may be implemented by the FdO<NUM> controller. The FdO<NUM> controller can receive inputs of measured FdO<NUM> and target FdO<NUM>. The FdO<NUM> controller can then output a hypoxic gas inlet valve control signal to control the operation of the hypoxic gas valve based on a difference between these measured FdO<NUM> and target FdO<NUM> values. The FdO<NUM> controller may receive the target FdO<NUM> value that is output from the first control loop when the flow therapy apparatus is controlling to a target SpO<NUM>. In some configurations, the control signal of the FdO<NUM> controller may set the current of the hypoxic gas valve in order to control operation of the hypoxic gas valve. Additionally, or alternatively, the FdO<NUM> controller could detect changes to the measured FdO<NUM> and alter the position of the valve accordingly. In some configurations, the user manually sets a target SpO<NUM> or oxygen concentration, and the second control loop can operate independently without receiving the target FdO<NUM> from the first control loop. Rather, the target FdO<NUM> can be received from user input or a default value.

The FiO<NUM> could be controlled within a set of limits, such as pre-determined limits programmed into a memory of device that can be user-customizable in some cases. If the device allows for the supply of nitrogen to be suddenly blocked such that the device returns to delivery of normoxic gas, then such a function could be considered separate and unrestricted by any of the following limits. With each set of limits, an altitude e.g., in meters or feet, can be provided that roughly corresponds to an equivalent partial pressure of oxygen, as this could be displayed alternatively or in addition to the FiO<NUM> reading. The following FiO<NUM> limits serve as examples of possible ranges, but the FiO<NUM> range could be between any two values, including a lower limit from one range and an upper limit from another.

In some embodiments, the device could operate based upon a target SpO<NUM> measurement. One advantage of controlling the hypoxic gas delivery based on SpO<NUM> is that it allows the device to adjust the FiO<NUM> (and equivalent altitude) with the exercise intensity. For example, if the user begins exercising at a higher level of intensity, the user's SpO<NUM> may begin to drop. In response, the device would increase the FiO<NUM> in order to maintain the target SpO<NUM>. In this situation, the device would effectively be raising the FiO<NUM> in response to increased exercise intensity. The target SpO<NUM> could be a pre-set value, a selected value, a pre-set range, a selected range, or a value that changes over time based on a selected therapy program. The SpO<NUM> reading could be directly fed into the device, and the difference between the target SpO<NUM> and measured SpO<NUM> could be used to control a proportional valve on the nitrogen inlet, and therefore the oxygen content of the gas delivered (FiO<NUM>), similar to the one discussed above. As described above, the device controls FiO<NUM> by changing FdO<NUM>, and assumes inspiratory demand is met, and therefore in such a scenario FiO<NUM> is equal to FdO<NUM>. If inspiratory demand is not met, the device can still control FdO<NUM> according to a target SpO<NUM>, as the controller would continue to change FdO<NUM> (and in turn assumed FiO<NUM>) until the target SpO<NUM> is achieved. By constantly using feedback from the SpO<NUM> sensor to control the nitrogen inflow, the target SpO<NUM> can be reached by altering the oxygen content of the gas. In some embodiments, the measured SpO<NUM>, target SpO<NUM>, and/or FiO<NUM> can be displayed. The device could include limits on the amount of nitrogen that the valve can allow through and/or a valve position so that an overly dangerous hypoxic composition is not delivered. Additionally, the device could be configured to allow for control of SpO<NUM> when an SpO<NUM> sensor is used, but to then default back to one of the earlier FiO<NUM> control methods when the SpO<NUM> is not present. Additionally or alternatively, the system can use feedback from other proxy measurements of exertion, such as heart rate, blood pressure, respiratory rate, or heart rate variability to adjust the FiO<NUM> (and equivalent altitude).

SpO<NUM> can in some embodiments be controlled between a set of pre-set or other limits. The following are a few non-limiting examples of possible limits, in practice SpO<NUM> could be limited between any two values, including any reasonable combination of a lower value from one range and an upper value from another.

The device could be for extended use, for example, all the time (e.g., <NUM> hours a day); using the device only when awake; using the device only when sleeping; using the device only when exercising; using the device only when not exercising; using the device for a set amount of time, e.g., about, at least about, or no more than about <NUM> minutes, <NUM> minutes, <NUM> hour, <NUM> hours, <NUM> hours, <NUM> hours, <NUM> hours, <NUM> hours, <NUM> hours, <NUM> hours, <NUM> hours, <NUM> hours, <NUM> hours, <NUM> hours, <NUM> hours, <NUM> hours, or <NUM> hours a day; or any logical combination of the above (e.g., only when awake and not exercising).

Intermittent use could entail using the device for a set amount of time, such as for example, shorter than about <NUM>, <NUM>, <NUM>, or <NUM> hour, or using the device for short bursts of about or less than about <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> minute interspaced with similar short recovery periods of about or less than about <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> minute, or only using the device while exercising, or any logical combination of the above (e.g., short bursts with interspaced recovery only during exercise).

In some embodiments, the use can be done once a week, or for <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> days out of a week, <NUM> weeks, or month for example.

In some embodiments, the use can be continued for a total period of time depending on the desired clinical result. The device can be used over a time period of, for example, about, at least about, or no more than about <NUM> week, <NUM> weeks, <NUM> weeks, <NUM> month, <NUM> months, <NUM> months, <NUM> months, <NUM> months, <NUM> months, <NUM> months, <NUM> months, or more or less.

The device could be used in a therapy program that contains treatment periods that could be considered extended use as well as other periods that could be considered intermittent use, and could use different SpO<NUM> target ranges appropriate for both. For example, the device could be used in a lower SpO<NUM> target range while exercising, as well as a higher SpO<NUM> target range when not exercising for the rest of the day.

In some embodiments, personalized training methods and altitude equivalent oxygen concentrations for therapy can determined by observing how different individuals acclimatize at different rates. In general, less than about <NUM> meters above sea level is commonly described as "low altitude", as noticeable effects generally begin to take place at about <NUM> meters. From about <NUM> meters to about <NUM> meters is often referred to as the "high altitude" region, with regions over about <NUM> meters being the "very high altitude", and can be potentially dangerous to train at in some cases, especially if not given the proper time to acclimatize. High altitude training tends to occur in the region about <NUM> meters to about <NUM> meters, although this varies with training regimes, particularly the activity performed in the high altitude region and the length of time spent there. Some activity regimes include:.

<FIG> illustrates a block diagram of an embodiment of a controller <NUM>. The controller <NUM> can include programming instructions for detection of input conditions and control of output conditions. The programming instructions can be stored in a memory <NUM> of the controller <NUM>. The programming instructions can correspond to the methods, processes and functions described herein. The programming instructions can be executed by one or more hardware processors <NUM> of the controller <NUM>. The programming instructions can be implemented in C, C++, JAVA, or any other suitable programming languages. Some or all of the portions of the programming instructions can be implemented in application specific circuitry <NUM> such as ASICs and FPGAs.

The controller <NUM> can also include circuits <NUM> for receiving sensor signals. The controller <NUM> can further include a display <NUM> for transmitting status of the user and the respiratory assistance system. The display <NUM> can also show warnings. The display <NUM> can be configured to display characteristics of sensed gas(es) in real time. The controller <NUM> can also receive user inputs via the user interface such as display <NUM>. The user interface may alternatively or additionally comprise buttons or a dial. The user interface may alternatively or additionally comprise a touch screen.

Any of the features of the flow therapy apparatus described herein, including but not limited to the humidifier, the flow generator, the user interface, the controller, and the user breathing conduit configured to couple the gases flow outlet of the respiratory system to the user interface, can be combined with any of the sensor modules described herein.

<FIG> illustrates a block diagram of the motor/sensor module <NUM>, which is received by the recess <NUM> in the flow therapy apparatus (shown in <FIG> and <FIG>). The motor/sensor module can include a blower <NUM>, which entrains room air to deliver to a user. The blower <NUM> can be a centrifugal blower.

Room air can enter an ambient/room air inlet <NUM>, which enters the blower <NUM> through an inlet port <NUM>. The inlet port <NUM> can include a valve <NUM> through which a pressurized gas may enter the blower <NUM>. The valve <NUM> can control a flow of nitrogen or other auxiliary gas into the blower <NUM>. The valve <NUM> can be any type of valve, including a proportional valve or a binary valve. In some embodiments, the valve can be on the nitrogen supply line, e.g., a nitrogen source bottle or other reservoir, and manually or automatically adjusted to alter the amount of nitrogen being delivered. In some embodiments, the inlet port does not include a valve.

The blower <NUM> can operate at a motor speed of greater than <NUM>,<NUM> RPM (revolutions per minute) and less than <NUM>,<NUM> RPM, greater than <NUM>,<NUM> RPM and less than <NUM>,<NUM> RPM, or between any of the foregoing values. Operation of the blower <NUM> mixes the gases entering the blower <NUM> through the inlet port <NUM>. Using the blower <NUM> as the mixer can decrease the pressure drop that would otherwise occur in a system with a separate mixer, such as a static mixer comprising baffles, because mixing requires energy.

The mixed air can exit the blower <NUM> through a conduit <NUM> and enters the flow path <NUM> in the sensor chamber <NUM>. A sensing circuit board with sensors <NUM> can positioned in the sensor chamber <NUM> such that the sensing circuit board is at least partially immersed in the gases flow. At least some of the sensors <NUM> on the sensing circuit board can be positioned within the gases flow to measure gas properties within the flow. After passing through the flow path <NUM> in the sensor chamber <NUM>, the gases can exit <NUM> to the humidification chamber.

Positioning sensors <NUM> downstream of the combined blower and mixer <NUM> can increase accuracy of measurements, such as the measurement of gases fraction concentration, including nitrogen and/or oxygen concentration, over systems that position the sensors upstream of the blower and/or the mixer. Such a positioning can give a repeatable flow profile. Further, positioning the sensors downstream of the combined blower and mixer avoids the pressure drop that would otherwise occur, as where sensing occurs prior to the blower, a separate mixer, such as a static mixer with baffles, is required between the inlet and the sensing system. The mixer can introduce a pressure drop across the mixer. Positioning the sensing after the blower can allow the blower to be a mixer, and while a static mixer would lower pressure, in contrast, a blower increases pressure. Also, immersing at least part of the sensing circuit board and sensors <NUM> in the flow path can increase the accuracy of measurements because the sensors being immersed in the flow means they are more likely to be user to the same conditions, such as temperature and pressure, as the gases flow and therefore provide a better representation of the gas characteristics.

Turning to <FIG>, the gases exiting the blower can enter a flow path <NUM> in the sensor chamber <NUM>, which can be positioned within the motor and/or sensor module. The flow path <NUM> can have a curved shape. The flow path <NUM> can be configured to have a curved shape with no sharp turns. The flow path <NUM> can have curved ends with a straighter section between the curved ends. A curved flow path shape can reduce pressure drop in a gases flow without reducing the sensitivity of flow measurements by partially coinciding a measuring region with the flow path to form a measurement portion of the flow path.

A sensing circuit board <NUM> with sensors, such as ultrasonic transmitters, receivers, humidity sensor, temperature sensor, flow rate sensor, and the like, can be positioned in the sensor chamber <NUM> such that the sensing circuit board <NUM> is at least partially immersed in the flow path <NUM>. Immersing at least part of the sensing circuit board and sensors in the flow path can increase the accuracy of measurements because the sensors immersed in the flow are more likely to be user to the same conditions, such as temperature and pressure, as the gases flow, and therefore provide a better representation of the characteristics of the gases flow. After passing through the flow path <NUM> in the sensor chamber <NUM>, the gases can exit to the humidification chamber.

With continued reference to <FIG>, openings <NUM> of the sensor chamber <NUM> can hold acoustic transmitters, such as ultrasonic transducers which form an acoustic axis along at least a portion of the flow path <NUM> to measure properties or characteristics of the gases within the flow. The ultrasonic transducers can act as both transmitters and receivers.

A human user performed a <NUM> trial run on a gravel track and recorded a time of <NUM> minutes and <NUM> seconds. The user's best time over recent years has been <NUM> minutes and <NUM> seconds. <NUM> weeks later, the user commenced use of a high flow device, such as a high flow device coupled to a nasal cannula patient interface as disclosed herein with delivery of a hypoxic gas composition including enriched nitrogen at an altitude equivalent of about <NUM>,<NUM> (about <NUM>% oxygen concentration in the hypoxic gas composition) for <NUM>-<NUM> hours a night, <NUM> days a week, for a total of three weeks. During this time, the user typically maintained the hypoxic gas flow rate at between about <NUM> liters/minute and about <NUM> liters/minute, and occasionally raised the hypoxic gas flow rate to at least <NUM> liters/minute for a couple minutes to verify its effects on his blood saturation, and using a pulse oximeter was able to observe his blood oxygen saturation dropping below <NUM>%. After three weeks of the therapy, the user took a week off with no therapy, and then ran a <NUM> trial run on a grass track (which typically produces much slower times than gravel) and recorded a much faster time of <NUM> minutes and <NUM> seconds. The user attributed the surprising and unexpected improvement in his run time to use of the high flow device disclosed herein.

Features, materials, characteristics, or groups described in conjunction with a particular aspect, embodiment, or example are to be understood to be applicable to any other aspect, embodiment or example described in this section or elsewhere in this specification unless incompatible therewith. The protection is not restricted to the details of any foregoing embodiments. The protection extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Furthermore, certain features that are described in this disclosure in the context of separate implementations can also be implemented in combination in a single implementation.

Claim 1:
A nasal high flow system (<NUM>) configured for providing a hypoxic flow of gases to a user, comprising:
an apparatus comprising a gas flow path, an ambient air inlet (<NUM>'), and a hypoxic gas source inlet (<NUM>') configured to connect to a hypoxic gas source and configured to create a hypoxic gas composition upon mixing of ambient air and hypoxic gas;
a user interface (<NUM>) comprising a nasal cannula comprising nasal prongs (<NUM>);
a gas flow generation element (<NUM>) configured to deliver the hypoxic gas composition to nares of the user at a predetermined high flow rate of at least about <NUM> liters/minute;
a sensor (<NUM>) configured to measure a physiological parameter of the user, wherein the physiological parameter is blood oxygen saturation; and
a controller (<NUM>) configured to automatically control the delivery of the hypoxic gas composition based on the measured physiological parameter;
wherein the nasal cannula is non-sealed.