Breathing apparatus and control method

Abstract

A respiratory device configured to deliver a flow of gas to a user for respiratory therapy. The flow generator is operable to generate a flow of gas. The controller is operable to control one or more characteristics of the flow of gas provided to the user by controlling a motor speed of the flow generator. The controller is configured to receive one or more input treatment settings representing one or more characteristics desired for the flow of gas generated during a treatment session. The controller predicts whether a steady state temperature of the device will exceed a high temperature condition threshold based at least in part on the input treatment settings and a thermal model of the device. The controller may generate an alarm and / or initiate alarm responsiveness countermeasure control actions in response to the prediction to reduce a risk of the device exceeding the high temperature condition threshold.

Description

[Technical field]

[0001] The present disclosure relates to devices and control methods for providing respiratory assistance and / or therapy using a flow of gas. [Background technology]

[0002] Respiratory devices are used to deliver a flow of gas to a user or patient in a variety of environments, such as hospitals, medical facilities, home care, or domestic environments. Respiratory devices, such as flow therapy apparatuses, may include an oxygen inlet to allow for the delivery of supplemental oxygen along with the flow of gas, and / or a humidification device to deliver heated and humidified gas. Flow therapy apparatuses may allow for the adjustment and control of characteristics of the gas flow, including flow rate, temperature, gas concentration such as oxygen concentration, humidity, pressure, etc. Summary of the Invention [Means for solving the problem]

[0003] In a first aspect, the present disclosure relates to a respiratory assistance device configured to provide a flow of gas to a user for respiratory therapy, comprising: a flow generator operable to generate a flow of gas; and a controller operatively connected to the flow generator and operable to control a flow rate of the flow of gas by controlling a motor speed of the flow generator, the controller being configured to receive an input representing a set flow rate at which the device will generate the flow of gas for a desired therapy session, predict whether a steady state temperature of the device will exceed a high temperature condition threshold based at least in part on the motor speed required to generate the set flow rate, and generate a predicted high temperature condition signal if the high temperature condition threshold is exceeded based on the prediction.

[0004] In one configuration, predicting whether the steady state temperature will exceed the hot condition threshold is based on determining whether the required motor speed exceeds a maximum allowable motor speed, the maximum allowable motor speed representing the highest motor speed that the device can maintain for a set flow rate without causing the steady state temperature to exceed the hot condition threshold.

[0005] In one configuration, the maximum allowable motor speed is based on or is a function of a predetermined thermal model.

[0006] In one configuration, a thermal model represents the heat generated by the flow generator as a function of flow rate and motor speed.

[0007] In one configuration, a thermal model represents the heat generated by the flow generator and one or more non-flow generator heat sources, where the heat generated by the flow generator is a function of flow rate and motor speed.

[0008] In one configuration, a thermal model is configured to represent one or more non-flow generator heat sources with respective preset values ​​that represent an estimate of the maximum amount of heat that can be generated by each of the one or more non-flow generator heat sources during operation.

[0009] In one configuration, the thermal model is configured to represent one or more non-flow generator heat sources with one or more respective preset or configurable safety values ​​that represent the maximum amount of heat predicted to be generated by each heat source in a desired treatment session.

[0010] In one configuration, the maximum allowable motor speed for a flow range is represented or defined by a predetermined threshold line plotted on a motor speed versus flow graph, with the area above the threshold line representing a hot condition zone.

[0011] In one configuration, the prediction of whether the steady state temperature will exceed the hot condition threshold is based on determining whether the combination of required motor speed and set flow rate is in the hot condition zone.

[0012] In one configuration, predicting whether the steady state temperature will exceed the high temperature threshold is based on predicting the steady state temperature as a function of the required motor speed and the set flow rate, and determining whether the predicted steady state temperature will exceed the high temperature threshold.

[0013] In one configuration, predicting the steady state temperature includes determining an estimate from a predetermined thermal model.

[0014] In one configuration, a thermal model represents the heat generated by the flow generator as a function of flow rate and motor speed.

[0015] In one configuration, a thermal model represents the heat generated by the flow generator and one or more non-flow generator heat sources, where the heat generated by the flow generator is a function of flow rate and motor speed.

[0016] In one configuration, a thermal model is configured to represent one or more non-flow generator heat sources with respective preset values ​​that represent an estimate of the maximum amount of heat that can be generated by each of the one or more non-flow generator heat sources during operation.

[0017] In one configuration, the thermal model is configured to represent one or more non-flow generator heat sources with one or more respective preset or configurable safety values ​​that represent the maximum amount of heat predicted to be generated by each heat source in a desired treatment session.

[0018] In one configuration, the controller is configured to predict whether the steady state temperature of the device will exceed a high temperature condition threshold by determining whether the required motor speed exceeds a maximum allowable motor speed for a set flow rate, the maximum allowable motor speed representing the high temperature condition threshold.

[0019] In one configuration, the maximum allowable motor speed for a set flow rate is determined based on or is a function of a predetermined thermal model.

[0020] In one configuration, the thermal model is a function or threshold line representing a maximum allowable motor speed for a range of set flow rates, the thermal model being generated based at least in part on a high temperature condition threshold.

[0021] In one configuration, the controller is configured to predict whether a steady state temperature of the device will exceed a high temperature threshold by predicting the steady state temperature based on, or as a function of, a predetermined thermal model, a set flow rate, and a required motor speed, and determining whether the predicted steady state temperature exceeds the high temperature threshold.

[0022] In one configuration, the thermal model generates a temperature variable representing a predicted steady state temperature based at least on the set flow rate and the required motor speed such that the thermal model is based at least on the heat generated by the flow generator.

[0023] In one configuration, a thermal model generates a temperature variable representing a predicted steady-state temperature based at least on the set flow rate, the required motor speed, and one or more other parameters representing non-flow generator heat sources of or associated with the apparatus that contribute to the steady-state temperature of the apparatus.

[0024] In one configuration, the controller is configured to determine whether a temperature variable representing a predicted steady state temperature exceeds a high temperature condition threshold.

[0025] In one configuration, a thermal model represents one or more heat sources of or associated with the apparatus, including at least representing the heat generated by the flow generator as a function of motor speed and flow rate.

[0026] In one configuration, the thermal model further represents heat generated by one or more non-flow generator heat sources of or associated with the apparatus that contribute to the steady state temperature of the apparatus.

[0027] In one configuration, the thermal model is based at least in part on a theoretical thermal model of the device.

[0028] In one configuration, the thermal model is based at least in part on empirical thermal data associated with the operation of the device.

[0029] In one configuration, the thermal model is based at least in part on one or more pre-set or configurable safety values.

[0030] In one configuration, the controller is configured to determine a required motor speed of the flow generator to generate a set flow rate.

[0031] In one configuration, the controller is configured to determine the motor speed required to produce the set flow rate by increasing or varying the motor speed until the set flow rate is produced by the flow generator.

[0032] In one configuration, the controller is configured to receive a set flow rate input for a desired treatment session when the device is in a start-up or standby state with the flow generator stopped or idling at a non-therapeutic speed before the desired treatment session is initiated.

[0033] In one configuration, the controller is configured to receive a set flow rate input while the device is already operating in a current treatment session at a first flow rate, the set flow rate input being a different second flow rate associated with a new desired treatment session.

[0034] In one configuration, the controller is configured to predict whether the steady state temperature of the apparatus will exceed the high temperature condition threshold based at least in part on the required motor speed by: estimating a first amount of heat representative of heat contributed to the steady state temperature by one or more non-flow generator heat sources; estimating a maximum allowable motor speed of the flow generator corresponding to a second amount of heat representative of heat contributed to the steady state temperature by the flow generator such that the sum of the first amount of heat and the second amount of heat does not cause the steady state temperature to exceed the high temperature condition threshold; determining a motor speed required for a set flow rate by increasing or changing the motor speed of the flow generator to a motor speed required for the flow generator to generate the set flow rate; and predicting that the steady state temperature of the apparatus will exceed the high temperature condition threshold if the determined required motor speed exceeds the estimated maximum allowable motor speed.

[0035] In one configuration, the controller is configured to predict whether a steady state temperature of the apparatus will exceed a high temperature threshold based at least in part on the required motor speed by: increasing or varying a motor speed of the flow generator to a motor speed required for the flow generator to produce a set flow rate, thereby determining a motor speed required for the set flow rate; estimating a first steady state temperature value representative of heat contributed to the steady state temperature by the flow generator; estimating a second steady state temperature value representative of heat contributed to the steady state temperature by one or more non-flow generator heat sources; predicting a steady state temperature of the apparatus by summing the first steady state temperature value and the second steady state temperature value; and evaluating whether the predicted steady state temperature exceeds a high temperature threshold.

[0036] In one configuration, the one or more non-flow generator heat sources include any one or more of the following non-flow generator components or variables of, connected to, or associated with the device: ambient temperature of the environment surrounding the device, a battery or power source, a heater plate of a humidifier, heater wires of a patient interface conduit, electronic circuits or components, a printed circuit board (PCB), a graphical user interface, and / or a display screen.

[0037] In one configuration, the steady state temperature can be configured to represent any predictable temperature of interest of, within, or associated with the device.

[0038] In one configuration, steady state temperature refers to a sustained and / or stable temperature parameter, as opposed to a transient temperature parameter.

[0039] In one configuration, the steady state temperature represents a predicted temperature parameter after the device has been operated in a desired treatment session at a set flow rate for at least a predetermined minimum time such that the steady state temperature represents a sustained and / or stable temperature parameter.

[0040] In one configuration, the steady state temperature of the device represents a predicted temperature of the gas flow within the device at a particular region or location within the gas flow path of the device.

[0041] In one configuration, the steady state temperature of the device represents the predicted temperature within a particular location or region of the main housing of the device.

[0042] In one arrangement, the steady state temperature of the apparatus represents a predicted temperature at or within a particular component or part of the respiratory assistance apparatus.

[0043] In one configuration, the steady state temperature of the device represents a predicted general overall temperature parameter associated with the device based on a thermal model of the device and / or one or more heat sources of interest of or associated with the device.

[0044] In one configuration, the high temperature threshold is a configurable temperature parameter.

[0045] In one configuration, the overtemperature threshold is a temperature value.

[0046] In one configuration, the hot condition threshold is a temperature parameter that is predetermined or selected based on the characteristics of the device and / or the particular type of steady state temperature expected.

[0047] In one configuration, the steady state temperature represents a predicted temperature parameter related to the temperature of the gas flow at a particular region or location within the device, and the high temperature threshold represents a gas temperature safety threshold or value beyond which malfunction, damage to the device, and / or increased safety risk to the user may occur.

[0048] In one configuration, the steady state temperature represents a predicted temperature parameter for a particular location or area of ​​the main housing of the device, and the high temperature threshold is configured to represent a housing temperature safety threshold or value beyond which malfunction, damage to the device, and / or increased safety risk to the user may occur.

[0049] In one configuration, the controller is configured to issue an alarm if a predicted high temperature condition signal is generated.

[0050] In one configuration, the alarm comprises one or more types of alarm: audible, visual, tactile, and / or haptic.

[0051] In one configuration, the alarm comprises an alarm message or indication on a display screen or user interface of the device.

[0052] In one configuration, the controller is configured to overrule the set flow rate and disable the motor or slow the motor to idle speed if an alarm is generated.

[0053] In one configuration, the controller is configured to limit the motor speed to a maximum allowable motor speed if an alarm is issued and generate an alarm message or indication on a display screen or user interface of the device, the maximum allowable motor speed indicating the highest motor speed that the device can maintain for the set flow rate without the steady state temperature exceeding the high condition threshold.

[0054] In one configuration, the controller is configured to reduce the power applied to one or more non-flow generator components of the device or disable operation of one or more non-flow generator components to reduce their thermal output when an alarm is issued.

[0055] In one configuration, the controller is configured to reduce power applied to a heater plate of the humidifier and / or heater wires of the patient interface conduit and / or disable the heater plate and / or heater wires if an alarm is issued.

[0056] In one configuration, the controller is configured to reduce or disable charging circuitry associated with the device's battery if the alarm is activated.

[0057] In one configuration, the steady state temperature and the hot state threshold are expressed and determined with reference to a temperature metric or a heat or thermal energy metric.

[0058] In one configuration, the flow generator includes one or more thermistors disposed within the flow generator housing or in thermal communication with the flow generator or the flow generator motor, the thermistors configured to sense a temperature of the flow generator and / or the flow generator motor or to sense a temperature associated with the flow generator and / or the flow generator motor and generate a representative temperature signal.

[0059] In one configuration, the apparatus further comprises a humidifier.

[0060] In one configuration, the humidifier comprises a humidification chamber (e.g. a humidified water chamber). In one configuration, the humidification chamber may be removable from the device.

[0061] In one configuration, the humidifier comprises a heater plate or heater component or element configured to heat the water in the chamber.

[0062] In one configuration, the device further comprises a main housing. In one configuration, the main housing comprises the flow generator and the humidifier. In one example, the flow generator and the humidifier may be integrated into or provided within the same or a common main housing. For example, the humidifier may comprise a humidification chamber and a heater plate.

[0063] In one configuration, a main housing of the device contains the flow generator and humidifier (e.g., humidification chamber and heater plate) and one or more other heat sources of the device. For example, the one or more other heat sources may include any one or more or all of a battery or power source, heater wires, electronic circuitry or components, one or more printer circuit boards (PCBs), a graphical user interface, and / or a display system. In one configuration, the main housing contains or provides the flow generator, humidifier, battery or power source, and all other heat sources of the device. For example, all heat generating components may be provided in or integrated into a common main housing.

[0064] In a second aspect, the disclosure relates to a method of controlling a respiratory assistance device configured to provide a flow of gas to a user for respiratory therapy, the device comprising a flow generator operable to generate a flow of gas, and a controller operatively connected to the flow generator and operable to control a rate of the flow of gas by controlling a motor speed of the flow generator, the method being executable or implementable by the controller and including receiving an input representing a set flow rate at which the device will generate the flow of gas for a desired therapy session; predicting whether a steady state temperature of the device will exceed a high temperature condition threshold based at least in part on the motor speed required to generate the set flow rate; and generating a predicted high temperature condition signal if the high temperature condition threshold will be exceeded based on the prediction.

[0065] In a third aspect, the present disclosure relates to a respiratory assistance device configured to provide a flow of gas to a user for respiratory therapy, comprising a flow generator operable to generate a flow of gas, and a controller operably connected to the flow generator and operable to control one or more characteristics of the flow of gas provided to the user by controlling a motor speed of the flow generator, wherein the controller is configured to receive one or more input treatment settings representing one or more characteristics desired for the generated flow of gas provided to the user during a treatment session; predict, based at least in part on the one or more inputs or treatment settings and a thermal model of the device, one or more motor speed limits that prevent a steady state temperature of the device from exceeding a high temperature condition threshold; and control the flow generator to provide a flow of gas in accordance with or based on the input treatment settings, to the extent possible, while operating within the motor speed limits.

[0066] In one configuration, the input treatment settings include a set flow rate indicating a desired flow rate of gas delivered to a user for a flow treatment session.

[0067] In one configuration, the input treatment settings include one or more pressure settings related to a desired pressure of the flow of gas delivered to a user for a positive airway pressure treatment session.

[0068] In one configuration, a controller controls the flow generator to deliver a flow of gas in full compliance with the treatment settings while operating within the motor speed limits.

[0069] In one configuration, the controller controls the flow generator to deliver gas flow to a reduced level relative to the input treatment setting by operating within the motor speed limits.

[0070] In a fourth aspect, the disclosure provides a method of controlling a respiratory assistance device configured to provide a flow of gas to a user for respiratory therapy, the device comprising a flow generator operable to generate a flow of gas, and a controller operably connected to the flow generator and operable to control one or more characteristics of the flow of gas provided to the user by controlling a motor speed of the flow generator, the method being executable or implementable by the controller, the method including: receiving one or more input treatment settings representing one or more characteristics desired for the generated flow of gas provided to the user during a treatment session; predicting, based at least in part on the one or more input or treatment settings and a thermal model of the device, one or more motor speed limits that will prevent a steady state temperature of the device from exceeding a high temperature condition threshold; and controlling the flow generator to the extent possible toward providing a flow of gas in accordance with or based on the input treatment settings while operating within the motor speed limits.

[0071] In a fifth aspect, the present disclosure relates to a respiratory assistance device configured to provide a flow of gas to a user for respiratory therapy, comprising a flow generator operable to generate a flow of gas; and a controller operably connected to the flow generator and operable to control one or more characteristics of the flow of gas provided to the user by controlling a motor speed of the flow generator, wherein the controller is configured to: receive one or more input treatment settings representing one or more characteristics desired for the generated flow of gas provided to the user during a treatment session; predict one or more motor speed limits that prevent a steady state temperature of the device from exceeding a high temperature condition threshold based at least in part on the one or more inputs or treatment settings and a thermal model of the device; control the flow generator to provide the flow of gas in accordance with the input treatment settings; and issue an alarm and / or initiate alarm responsiveness control actions if the motor speed of the flow generator is operating outside the motor speed limits for a predetermined time to avoid or reduce a risk of the device exceeding the high temperature condition threshold.

[0072] In a sixth aspect, the disclosure relates to a method of controlling a respiratory assistance device configured to provide a flow of gas to a user for respiratory therapy, the device comprising a flow generator operable to generate a flow of gas, and a controller operatively connected to the flow generator and operable to control one or more characteristics of the flow of gas provided to the user by controlling a motor speed of the flow generator, the method being executable or implementable by the controller, the method including: receiving one or more input treatment settings representing one or more characteristics desired for the generated flow of gas provided to the user during a treatment session; predicting one or more motor speed limit values ​​that will prevent a steady state temperature of the device from exceeding a high temperature condition threshold based at least in part on the one or more inputs or treatment settings and a thermal model of the device; controlling the flow generator to provide the flow of gas in accordance with the input treatment settings; and issuing an alarm and / or initiating alarm responsiveness countermeasure control actions if the motor speed of the flow generator is operating outside of the motor speed limit values ​​for a predetermined time to avoid or reduce a risk of the device exceeding the high temperature condition threshold.

[0073] In a seventh aspect, the present disclosure relates to a respiratory assistance device configured to provide a flow of gas to a user for respiratory therapy, comprising a flow generator operable to generate a flow of gas, and a controller operably connected to the flow generator and operable to control one or more characteristics of the flow of gas provided to the user by controlling a motor speed of the flow generator, wherein the controller is configured to receive one or more input treatment settings representing one or more characteristics desired for the generated flow of gas provided to the user during a treatment session; predict whether a steady state temperature of the device will exceed a high temperature condition threshold based at least in part on the one or more of the input treatment settings and a thermal model of the device; and issue an alarm and / or initiate alarm responsiveness control measures in response to the prediction to avoid or reduce a risk of the device exceeding the high temperature condition threshold.

[0074] In one configuration, the input treatment settings include a set flow rate indicating a desired flow rate of gas provided to a user for a flow treatment session.

[0075] In one configuration, the input treatment settings include one or more pressure settings related to a desired pressure of the flow of gas delivered to a user for a positive airway pressure treatment session.

[0076] In an eighth aspect, the disclosure relates to a method of controlling a respiratory assistance device configured to provide a flow of gas to a user for respiratory therapy, the device comprising a flow generator operable to generate a flow of gas, and a controller operatively connected to the flow generator and operable to control one or more characteristics of the flow of gas provided to the user by controlling a motor speed of the flow generator, the method being executable or implementable by the controller, the method including receiving one or more input treatment settings representative of one or more characteristics desired for the generated flow of gas provided to the user during a treatment session; predicting whether a steady state temperature of the device will exceed a high temperature condition threshold based at least in part on the one or more of the input treatment settings and a thermal model of the device; and issuing an alarm and / or initiating alarm responsiveness control actions in response to the prediction to avoid or reduce a risk of the device exceeding the high temperature condition threshold.

[0077] In a ninth aspect, the present disclosure relates to a respiratory assistance device configured to provide a flow of gas to a user for respiratory therapy comprising a flow generator operable to generate a flow of gas and a controller configured to control the flow generator by controlling a motor speed of the flow generator, wherein the controller is configured to receive an input representing a set flow rate at which the device will generate a flow of gas for a therapy session; determine a motor speed of the flow generator corresponding to achievement of the set flow rate; and activate a visual and / or audible alarm if the determined motor speed of the flow generator for the set flow rate is predicted to cause a steady state temperature of the device to exceed a predetermined high temperature threshold.

[0078] In one configuration, a visual alarm is presented as an alarm notification or message on a display screen of the device.

[0079] In one configuration, the steady state temperature is a prediction of the temperature of or within the device in the future, the steady state temperature being calculated or predicted based at least in part on the determined motor speed.

[0080] In one configuration, the steady state temperature is predicted based on the determined motor speed and a thermal model of the device.

[0081] In one configuration, a thermal model defines a predicted temperature rise relative to a steady state temperature of the apparatus caused by one or more selected non-flow generator heat source components operating within the apparatus.

[0082] In one configuration, a thermal model defines a predicted temperature rise relative to the steady state temperature of the apparatus caused by the flow generator operating at a determined motor speed and one or more selected non-flow generator heat source components operating within the apparatus.

[0083] In a tenth aspect, the disclosure relates to a method of controlling a respiratory assistance device configured to provide a flow of gas to a user for respiratory therapy, the device comprising a flow generator operable to generate a flow of gas and a controller configured to control the flow generator by controlling a motor speed of the flow generator, the method being executable or implementable by the controller, the method including receiving an input representing a set flow rate at which the device will generate a flow of gas for a therapy session; determining a motor speed of the flow generator corresponding to achieving the set flow rate; and activating a visual and / or audible alarm if the determined motor speed of the flow generator for the set flow rate is predicted to cause a steady state temperature of the device to exceed a predetermined high temperature condition threshold.

[0084] In an eleventh aspect, the present disclosure relates to a respiratory assistance device configured to provide a flow of gas to a user for respiratory therapy, comprising a flow generator operable to generate a flow of gas, and a controller operably connected to the flow generator and operable to control a flow rate of the flow of gas by controlling a motor speed of the flow generator, wherein the controller is configured to receive an input representing a set flow rate at which the device will generate the flow of gas for a desired therapy session; determine a motor speed of the flow generator required to generate the set flow rate; and generate an alarm related to a potential future high temperature condition of the device, the alarm being generated within a predetermined time and / or before the actual steady state temperature of the device exceeds a temperature threshold or limit for the set flow rate.

[0085] In one configuration, the predetermined time is less than the duration of the treatment session.

[0086] In one configuration, the predetermined time is less than 30 minutes from the start of the treatment session.

[0087] In one configuration, the predetermined time is less than 15 minutes from the start of the treatment session.

[0088] In one configuration, the predetermined time is less than multiple seconds from the start of the treatment session.

[0089] In one configuration, the predetermined time includes a time a preset period of time before the actual steady state temperature of the device exceeds a temperature threshold or limit value, such that the controller is configured to issue the alarm at a time that is at least a preset period of time before the actual steady state temperature of the device exceeds a temperature threshold or limit value.

[0090] In one configuration, the controller is configured to ramp or increase the flow generator motor speed towards a set motor speed at the start of a treatment session, and the predetermined time for issuing an alarm includes a period of time during which the motor speed is ramping up to the set motor speed or a period of time after the motor speed reaches the set motor speed.

[0091] In one configuration, the controller is configured to issue an alarm if the actual steady state temperature of the device increases in a manner that causes a future potential high temperature condition of the device.

[0092] In one configuration, the controller is configured to predict whether a steady state temperature of the device will exceed a temperature threshold or limit based at least in part on the motor speed required to generate a set flow rate; and to issue an alarm if the predicted steady state temperature of the device exceeds the temperature threshold or limit.

[0093] In one configuration, the controller is configured to present an alarm notification or message on a display of the device when an alarm is triggered.

[0094] In one configuration, the alarm notification includes a message indicating that the current set flow rate will cause the actual steady state temperature of the device to exceed a temperature threshold or limit.

[0095] In one configuration, the controller is configured to predict a maximum steady state temperature of the device based on a thermal model and at least a motor speed required for a set flow rate; compare the predicted maximum steady state temperature of the device to a temperature threshold or limit; and issue an alarm if the predicted maximum steady state temperature exceeds the temperature threshold or limit.

[0096] In one configuration, a thermal model represents the heat generated by the flow generator as a function of flow rate and motor speed.

[0097] In one configuration, a thermal model represents the heat generated by the flow generator and one or more non-flow generator heat sources, where the heat generated by the flow generator is a function of flow rate and motor speed.

[0098] In one configuration, the controller is configured to predict a maximum steady state temperature of the device within a predetermined time period.

[0099] In one configuration, if an alarm is issued, the controller is configured to do one or more of the following: switch off the flow generator; reduce power applied to the heater plate of the humidifier of the device; reduce power applied to heater wires of the device or of a patient circuit conduit connected to the device; reduce power applied to the heater plate and heater wires; and / or present an audible and / or alphanumeric or visual message on a display of the device.

[0100] In a twelfth aspect, the present disclosure relates to a method of controlling a respiratory assistance device configured to provide a flow of gas to a user for respiratory therapy, the device comprising a flow generator operable to generate a flow of gas, and a controller operatively connected to the flow generator and operable to control a rate of the flow of gas by controlling a motor speed of the flow generator, the method being executable or performable by the controller, the method comprising: receiving an input representing a set flow rate at which the device will generate the flow of gas for a desired therapy session; determining a motor speed of the flow generator required to generate the set flow rate; and issuing an alarm related to a potential future high temperature condition of the device, the alarm being issued within a predetermined time and / or before an actual steady state temperature of the device exceeds a temperature threshold or limit for the set flow rate.

[0101] In a thirteenth aspect, the present disclosure relates to a non-transitory computer-readable medium having stored thereon computer-executable instructions that, when executed on one or more processing devices, cause the one or more processing devices to perform the method of any one of the previous aspects of the present disclosure.

[0102] Any one or more of the features and / or configurations mentioned with respect to one aspect of the present disclosure above may be applied to any one or more of the other aspects of the present disclosure above.

[0103] Definition or term or phrase The phrase "computer-readable medium" should be construed to include a single medium or multiple media. Examples of multiple media include centralized or distributed databases and / or associated caches. These multiple media store one or more sets of computer-executable instructions. The phrase "computer-readable medium" should also be interpreted to include any medium capable of storing, encoding or carrying a set of instructions for execution by a processor of a computing device, causing the processor to perform any one or more of the methods described herein. A computer-readable medium may also store, encode or carry data structures used by or associated with these sets of instructions. The phrase "computer-readable medium" includes solid-state memories, optical media, and magnetic media.

[0104] The term "comprising" as used in this specification and the claims means "consisting at least in part of." When interpreting each statement in this specification and the claims that contains the term "comprising," there may be features other than those preceded by the term. Related terms such as "comprise" and "comprises" are to be interpreted in the same manner.

[0105] The term "respiratory apparatus" as used herein and in the claims, unless the context indicates otherwise, is intended to mean any type or form of apparatus, machine, system, or device configured to provide and / or generate a flow of gas to a user for the purpose of respiratory assistance, respiratory therapy, including apparatus that provide one or more different modes of operation and types of assistance or treatment, whether flow-controlled, pressure-controlled, or otherwise, and including apparatus configured or operable to provide flow therapy, high-flow therapy, oxygen therapy, positive airway pressure (PAP) therapy, such as, but not limited to, continuous positive airway pressure (CPAP) therapy or bilevel CPAP (BiPAP) therapy, and the terms "flow therapy apparatus," "respiratory therapy apparatus," "respiratory support apparatus," and "respiratory support apparatus" may be used to refer to types of "respiratory apparatus," depending on the context.

[0106] The phrase "flow generator," as used in this specification and claims, unless the context indicates otherwise, is intended to mean any device, system, component, or arrangement configured to generate a flow of pressurized gas, including, but not limited to, a blower having an impeller driven by a motor, compressor, or other source of pressurized gas.

[0107] The term "temperature" as used herein and in the claims, unless the context suggests otherwise, is intended to mean a measure or parameter representing heat or thermal energy, which may be expressed in Celsius (C), Fahrenheit (F), or Kelvin (K), or any equivalent, and is also intended to capture indirect related measures or metrics related to temperature, such as direct measures of heat or thermal energy in metrics such as British Thermal Units (Btu) or Joules, such that references to "temperature" in the context of the claimed predictive alarms of this disclosure are intended to encompass direct temperature metrics, and / or heat or thermal energy metrics. For example, references to temperatures exceeding a threshold value may be determined based on a temperature metric or a heat or thermal energy metric, such that predictive alarms may be implemented in the temperature metric domain or energy metric domain. Furthermore, in this context, references to a "thermal model" are not necessarily limited to models based on heat or thermal energy, but may also include or be considered equivalent to a "temperature model" based on a temperature metric or the like. Likewise, the terms "overtemperature" and "overheating," or variations thereof, may be used interchangeably.

[0108] The phrase "treatment session" as used herein and in the claims is intended to mean a period of operation of the respiratory device that may have a beginning and an end, unless the context suggests otherwise. A treatment session may have or be defined by a preset or predetermined duration, or may have a configurable duration defined by a time metric. Each period may be defined, for example, in hours and / or minutes. A treatment session may additionally or alternatively have a beginning and / or end defined by a target goal or metric that is measured or evaluated by sensed operating parameters of the device or sensed physiological parameters of the user. A treatment session may also be a random or ad-hoc session of any duration. A "treatment session" is intended to generally mean a session of use of the respiratory device for a specific, designated, or prescribed respiratory therapy, and / or a session of use of the device for general respiratory assistance or other general use.

[0109] The term "predict" as used herein and in the claims, unless the context indicates otherwise, is intended to mean determining or calculating, whether directly or indirectly, estimates or expectations relating to future states, conditions, and / or values ​​of or relating to parameters, variables, and / or aspects of the device. The phrases, terms, and / or descriptors "predictive," "forecast," and "projected" are used with the same general meaning unless the context indicates otherwise.

[0110] prior art References herein to patents, other external documents, or other sources of information are generally for the purpose of providing a context for discussing features of the present invention, and unless specifically noted otherwise, references to such external documents should not be construed as an admission that such documents or such sources are prior art or form part of the general knowledge in the art in any jurisdiction.

[0111] Number range Reference to a numerical range disclosed herein (e.g., 1-10) also includes reference to every rational number within that range (e.g., 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9, and 10) and every range of rational numbers within that range (e.g., 2-8, 1.5-5.5, and 3.1-4.7), and therefore every subdivision of every range explicitly disclosed herein is intended to be expressly disclosed thereby. These are merely examples of what is specifically intended, and all possible combinations of numerical values ​​between the lowest and highest values ​​recited shall be considered to be expressly disclosed in this application as well.

[0112] As used herein, the term "and / or" means "and" or "or," or both.

[0113] As used herein, "(s)" following a noun refers to the plural and / or singular form of that noun.

[0114] This disclosure contemplates the above-mentioned and the following configurations, by way of example only. [Brief description of the drawings]

[0115] [Figure 1A] 1 illustrates in diagrammatic form a flow therapy device; [Figure 1B] 1 illustrates a sensing circuit board including a flow sensor that may be used in a flow therapy device. [Diagram 2] FIG. 1 is a flow diagram illustrating the general process for predictive over-temperature alarm of the present disclosure. [Diagram 3] FIG. 2 is a flow diagram outlining a process for predictive over-temperature alarm of the present disclosure in accordance with a first embodiment. [Figure 4A] 1 is a graph of motor speed versus flow rate showing a maximum allowable motor speed curve for a first embodiment based on a blower-only thermal model. [Figure 4B]4A shows the graph of FIG. 4A with an alternative maximum allowable motor speed curve for the first embodiment based on an alternative, more complete thermal model that takes into account the blower heat source and one or more other non-blower heat sources. [Figure 4C] FIG. 4 is a flow diagram illustrating a decision tree implemented by the predictive over-temperature alarm of the first embodiment. [Diagram 5] FIG. 11 is a flow diagram outlining a process for predictive over-temperature alarm of the present disclosure in accordance with a second embodiment. [Figure 6A] 11 is a graph of motor speed versus flow rate showing steady state temperatures for motor speed-flow rate combinations compared to threshold curves for a thermal model used in a second embodiment; [Figure 6B] FIG. 11 is a flow diagram illustrating a decision tree implemented by the predictive over-temperature alarm of the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0116] In the following description, specific details are given to provide a thorough understanding of the embodiments. However, it will be understood by those skilled in the art that the embodiments may be practiced without these specific details. For example, software modules, functions, circuits, etc. may be shown in block diagrams in order to avoid obscuring the embodiments in unnecessary detail. In other instances, well-known modules, structures and techniques may not be shown in detail in order to avoid obscuring the embodiments.

[0117] It should also be noted that the embodiments may be described as a process that is depicted as a flowchart, a flow diagram, a structure diagram, or a block diagram. Although a flowchart may describe operations as a sequential process, many of the operations may be performed in parallel or simultaneously. Additionally, the order of operations may be rearranged. A process ends when its operations are completed. A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, etc. in a computer program. When a process corresponds to a function, its end corresponds to a return of the function to the calling function or to the main function.

[0118] 1. Overview Respiratory apparatus and devices may overheat under certain conditions. This overheating may be caused by heat generated by components within the apparatus or device, such as, but not limited to, the flow generator (e.g., blower), a power source such as a battery, a heating element or heater plate of a humidifier, heater wires of a patient interface conduit, electronic circuits and / or components including those provided on a printed circuit board (PCB), a display screen and / or graphical user interface, and other such components. Alternatively or additionally, overheating of a respiratory device may result from other heat sources, such as the surrounding environment, heated and / or humidified gas flowing through the device.

[0119] Some respiratory devices include temperature sensors that sense the temperature of one or more components. If the sensed or measured temperature of one or more components or the temperature of the gas delivered to the patient exceeds a threshold, the device will sound an alarm. One problem with such existing temperature alarms relates to the time it takes for the device to sound an alarm after a treatment session has begun. In a typical use case, a nurse (or patient or other user) connects a specific interface (e.g., mask or cannula) to the patient and the device, enters certain device settings, and starts a treatment session. In a hospital, the nurse then moves on to other tasks, but after some time (e.g., after a few minutes or even an hour or more), a temperature alarm goes off. The nurse must then return to the patient, change the device settings, and restart the treatment session. Having to return to a patient who has already completed part of the treatment session can be frustrating for both the nurse (who is often time-poor) and the patient who has experienced an interruption in respiratory therapy or support. Similar problems exist in home care. For example, a patient or user may begin or begin a therapy session with a respiratory device at home, and then generally begin or continue other activities, such as reading, watching media on the device, and / or other recreational or homework activities. If a temperature alarm is then activated several minutes or an hour or more later, the user's or patient's therapy and recreational or other activities are interrupted and the therapy session must be reconfigured and resumed, which can be frustrating. Furthermore, if a temperature alarm is activated in either a hospital or home care setting, the nurse and / or patient must wait for the device to cool down to allow acceptable operation again, which can cause additional delays to re-starting respiratory therapy or support. Another problem with existing temperature alarms is that the alarm does not activate until the sensed temperature exceeds a threshold temperature, which allows the device and / or certain components of the device to be exposed to a certain degree of high temperature or heating, which can damage the components and / or shorten their usable lifespan and / or affect their accuracy or operational capabilities.

[0120] The present disclosure provides a respiratory device with a control system and method that implements a predictive maximum device temperature alarm (also referred to herein as a "predictive over-temperature alarm") that activates if inputs or operational therapy settings to the device for the initiation of a therapy session are likely to cause the steady state temperature of the device to exceed the overheat condition threshold. The predictive maximum device temperature alarm may also operate periodically, continuously, or may be initiated in response to a change in operational conditions during a therapy session (e.g., a user or patient or nurse or clinician changes an input or operational setting) to recheck or confirm whether a current, new, or changed input or operational setting is likely to cause the steady state temperature of the device to exceed the overheat condition threshold.

[0121] In a hospital or hospice environment, a predictive alarm can be configured to activate at or shortly after the start of a treatment session, which is likely to occur before the nurse leaves the patient and / or before the user or patient begins recreational activities or other tasks as described above. Thus, by using a predictive alarm, the nurse does not have to wait for the device to actually exceed a maximum steady-state temperature before issuing an alarm, thereby reducing the likelihood that the nurse will have to return to a patient who has already completed part of the treatment session. In a home care environment, where a user or patient uses a respiratory device at home, a predictive alarm can alarm early in the treatment session (e.g., seconds or minutes after a treatment setting is selected) to alert the user that the selected treatment setting or operating conditions will cause the respiratory device to exceed a high temperature threshold (i.e., an overheating condition). The user or home care patient can change or modify the treatment setting in response to the predictive alarm to minimize potential future interruptions or overheating alarms during a treatment session due to overheating of the device.

[0122] Additionally, the predictive alarms of the present disclosure further protect the device and / or its components from excessive temperatures or overheating because the alarm is triggered based on a predicted future steady state temperature associated with the device or devices exceeding a high temperature threshold, thus triggering the alarm before the device and / or components are exposed to undesirable high temperatures or overheating.

[0123] The presently disclosed predictive over-temperature alarm embodiments are described primarily in the context of a respiratory device in the form of a flow therapy device of the type described further below. The predictive over-temperature alarm embodiments are also described in the context of a pressure therapy device. However, it will be appreciated that the predictive over-temperature alarm may be adapted and implemented for any suitable respiratory device configured to deliver a flow of gas to a user for respiratory therapy or support, where the device includes or is exposed to a heat source that may cause an unsafe over-temperature condition. The predictive alarm may be applied to any respiratory device providing any one or more types of respiratory therapy and / or support, including, but not limited to, flow therapy, high flow therapy, oxygen therapy, positive airway pressure (PAP) therapy such as continuous positive airway pressure (CPAP) or bi-level positive airway pressure (BiPAP), and the like. Such respiratory devices typically include a controllable flow generator (e.g., a blower or compressor) and optionally a humidifier. Depending on the particular respiratory therapy or assistance being provided, the respiratory device may deliver a flow of gas via a sealed or unsealed interface (e.g., full face mask, nasal mask, oral mask, nasal cannula, etc.) according to set input flow or pressure values ​​or settings. For example, a predictive over-temperature alarm may be adapted to predict an over-temperature condition based on or in response to input or treatment settings applicable to the particular type of respiratory therapy or assistance being provided, whether flow rate settings, pressure level settings, and / or other relevant treatment settings (e.g., but not limited to, therapy duration, humidification settings, gas temperature settings, oxygen concentration settings, etc.).

[0124] It will be appreciated that the predictive over-temperature alarm is applicable to respiratory devices capable of providing multiple types of respiratory therapy and / or operating in multiple therapy modes. In one example, the respiratory device may be operable to provide flow therapy (e.g., high flow therapy) or pressure therapy (e.g., bi-level pressure therapy or CPAP therapy) depending on the mode of operation initiated. As will be appreciated, a controller of such a respiratory device may control the flow rate of the gas stream when providing flow therapy or support, and may control the pressure when providing pressure therapy or support. For flow therapy, the generated gas stream is typically delivered to the patient by a patient circuit comprising a conduit or tube and a non-sealed interface (e.g., a nasal cannula). For pressure therapy, the gas stream is typically delivered to the patient by a patient circuit comprising a conduit or tube and a sealed interface (e.g., a full face mask or nasal mask). In some configurations, the same type of conduit or tube may be used in both flow and pressure therapy modes. The patient circuit may be connected to the respiratory device or may be part of the respiratory device.

[0125] 2.Respirator By way of example only, various embodiments of the predictive over-temperature alarm are described in the context of a flow therapy device below, although application of the alarm is not limited to such configurations and devices, as explained above. The flow therapy device described below provides a context for further understanding the implementation and operation of the predictive over-temperature alarm. It will be understood that a flow therapy device is one type or form of respiratory device to which a predictive alarm may be applied, and is described by way of example only.

[0126] 1A illustrates a flow therapy device 10. The device 10 may comprise a main housing 100 including a flow generator 11 in the form of a motor / impeller arrangement (e.g., a blower), an optional humidifier 12, a controller 13, and a user interface 14 (e.g., comprising a display and input devices such as buttons, a touch screen, etc.). The controller 13 may be configured or programmed to control the operation of the device. For example, the controller may control the components of the device including, but not limited to, operating the flow generator 11 to generate a flow of gas (gas flow) for delivery to the patient, operating the humidifier 12 (if present) to humidify and / or heat the generated gas flow, controlling the flow of oxygen to the flow generator blower, receiving user input from the user interface 14 for reconfiguration of the device 10 and / or user defined operation, and outputting information to the user (e.g., on a display). The user may be a hospital patient, a home care patient or user, a medical professional (e.g., nurse, clinician, doctor), or anyone else interested in the use or operation of the device. As used herein, unless the context suggests otherwise, a "gas flow" may refer to any flow of gas that may be used in a respiratory assistance or breathing apparatus, such as a flow of ambient air, a flow containing substantially 100% oxygen, a flow containing some combination of ambient air and oxygen, and / or the like.

[0127] As explained above, a humidifier in the device is preferred but not required. Adding humidity to the gas stream increases comfort with therapy, improves patient compliance with therapy, and prevents or minimizes drying of the patient's airways. In high-flow therapy, a humidifier may be particularly advantageous, as high flow rates without humidity can dry out the airways and reduce lung function, e.g., reduced mucociliary transport. Humidity helps increase comfort by keeping the lungs warm and moist, and improves / maintains healthy mucociliary transport. Humidity may also help maintain physiological stability of compromised airways, which may aid in compliance with therapy.

[0128] The patient breathing conduit 16 is coupled at one end to a gas flow outlet 21 in the housing 100 of the flow therapy device 10. As an example, the patient breathing conduit may include a conduit connector at one end that mates to an electrical / pneumatic connector on the housing 100 of the flow therapy device. The conduit connector of the patient breathing tube has a pneumatic coupling that facilitates the flow of gas from the device to the conduit and an electrical connector. The electrical connector couples the heater wire of the breathing conduit to the electrical circuitry and / or controller of the flow therapy device. At another end, the patient breathing conduit 16 is coupled to a patient interface 17, such as a non-sealing nasal cannula having a manifold 19 and nasal prongs 18. Additionally or alternatively, the patient breathing conduit 16 may be coupled to a face mask, nasal mask, nasal pillow mask, endotracheal tube, tracheostomy interface, or the like. The gas flow generated by the flow therapy device 10 may be humidified and delivered to the patient via the patient conduit 16 through the cannula 17. The patient conduit 16 may have a heater wire 16a for heating the gas flow to the patient. The heater wire 16a may be under the control of the controller 13. The patient conduit 16 and / or the patient interface 17 may be considered part of the flow therapy device 10, or alternatively may be considered peripheral thereto. The flow therapy device 10, the respiratory conduit 16, and the patient interface 17 together may form a flow therapy system.

[0129] The controller 13 can control the flow generator 11 to generate a flow of gas at a desired flow rate. As an example, in one configuration, the controller is configured to control the desired flow rate by controlling the motor speed of the blower. In this configuration, the controller receives a target or set flow rate. The controller then calculates a set motor speed corresponding to the target flow rate. In one configuration, the set motor speed can be calculated based on the target or set flow rate and a model or formula / function or look-up table. As an example, the model or formula / function or look-up table can relate the flow generation to a set motor speed. In another configuration, the set motor speed may be calculated based on the input of the function, model, or formula, and one or more sensor inputs (e.g., a motor speed sensor and / or a flow sensor and / or other sensors). The controller 13 can also control the supplemental oxygen inlet to enable delivery of supplemental oxygen, and the humidifier 12 (if present) can humidify the flow of gas and / or heat the flow of gas to an appropriate level and / or the like. In this configuration, the humidifier 12 comprises a water or humidification chamber component through which the gas flows and a heater plate or heater component configured to heat the water in the chamber. The gas flow is conducted to the patient through a patient conduit 16 and a cannula 17. The controller 13 can also control a heating element in the humidifier 12 (e.g., a heater plate in the water or humidification chamber through which the gas flows) and / or a heating element 16a in the patient conduit 16 to heat the gas to a desired temperature for a desired level of therapy and / or comfort for the patient. The controller 13 can be programmed with or can determine an appropriate target temperature for the gas flow.

[0130] The oxygen inlet port 28 may include a valve that allows pressurized gas to enter the flow generator or blower. The valve may control the flow of oxygen to the flow generator (e.g., blower). The valve may be any type of valve, including a proportional valve or a binary valve. In one configuration, the valve is preferably a proportional type valve so that the device can control different concentrations of oxygen. The oxygen supply through the valve may be a high pressure oxygen source. Optionally, the device may include an additional oxygen inlet to allow low pressure oxygen to be introduced into the breathing device. The high pressure and / or low pressure oxygen is mixed with the ambient air inlet or inlets drawn into the device before the oxygen air humidity is humidified. The oxygen source may be an oxygen tank or a hospital oxygen supply. Medical oxygen is typically 95-100% pure. Less pure oxygen sources may also be used. In other configurations, ambient air may be augmented with any other suitable supplemental gas, such as, but not limited to, nitrogen, heliox, nitrous oxide, etc. Again, the auxiliary gas inlet port may be provided with a controllable valve to control the flow rate or supply of auxiliary gas, thereby controlling the concentration and / or composition of gas in the gas stream or flow delivered to the end user or patient.

[0131] The flow therapy device 10 can measure and control the oxygen content of the gas delivered to the patient and therefore the oxygen content of the gas inhaled by the patient. During high flow therapy, the high flow rate of the delivered gas typically approaches, is, or exceeds the patient's peak inspiratory demand. That is, the amount of gas delivered by the device to the patient during inspiration will match or exceed the amount of gas inhaled by the patient during inspiration. Thus, high flow therapy not only clears exhaled gases from the patient's airway, but also helps to prevent entrainment of ambient air as the patient inhales. As long as the flow rate of the delivered gas meets or exceeds the patient's peak inspiratory demand, entrainment of ambient air is prevented and the gas delivered by the device will be substantially the same as the gas inhaled by the patient. Therefore, the oxygen concentration measured in the device (fraction of delivered oxygen, FdO2) is substantially the same as the oxygen concentration the user is inhaling (fraction of inspired oxygen, FiO2), and therefore these terms can be considered equivalent.

[0132] Operational sensors 3a, 3b, 3c, such as flow, temperature, humidity, and / or pressure sensors, can be located at various locations within the flow therapy device 10. Additional sensors (e.g., sensors 20, 25) can be located at various locations on the patient conduit 16 and / or cannula 17 (e.g., there may be a temperature sensor 29 at or near the end of the inspiratory tube). Output from the sensors can be received by the controller 13 to assist the controller in operating the flow therapy device 10 to provide an appropriate therapy. In some configurations, providing an appropriate therapy includes meeting (e.g., delivering gas at a flow rate close to, at, or above) the patient's peak inspiratory demand. The device 10 can have a transmitter and / or receiver 15, or a communication module, to enable the controller 13 to receive signals 8 from the sensors and / or control various components of the flow therapy device 10, including, but not limited to, the flow generator 11, the humidifier 12, and the heater wires 16a, or accessories or peripherals associated with the flow therapy device 10. Additionally or alternatively, the transmitter and / or receiver 15, or communication module, may deliver data to a remote server, enable remote control of the device 10, or transmit data to other remote devices or systems, such as, but not limited to, external monitoring devices or systems. In some configurations, the transmitter and / or receiver 15 may be or include any one or more of the following: a modem, a Wifi module, a Bluetooth module, an infrared module, and / or an NFC module. In one exemplary configuration, the respiratory device comprises at least one or more of a modem, a Wifi module, a Bluetooth module, an infrared module, an NFC module, and / or any other wireless communication module to enable communication of data, such as, but not limited to, usage data, compliance data, and / or device-related data (e.g., via a wireless communication link or wireless data link).By way of example, the device-related data may include, but is not limited to, alarm data associated with triggered alarms, sensor data, or other data that may be used to perform diagnostics on the device. This device-related data may be sent or transmitted to an external server or processing system that may process the data to identify faults or perform other diagnostics based on the device-related data. This processing may allow repairs and / or maintenance of the device to be performed based on the output data from the diagnostic analysis.

[0133] Oxygen can be measured by placing one or more gas composition sensors (such as an ultrasonic transducer system (also referred to as an ultrasonic sensor system)) after mixing of the oxygen with the ambient air is complete. Measurements can occur within the device, in the delivery conduit, at the patient interface, or at any other suitable location. By way of example, a gas composition sensor (e.g., an oxygen concentration sensor) can be positioned between the blower and the humidifier. The blower mixes the incoming oxygen supply with the ambient air to generate or form an oxygen-enriched gas stream. The oxygen concentration sensor can be positioned in the bulk gas flow path of the device (i.e., the main gas flow path from the inlet through the blower to the humidifier to the outlet), or the sensor may be located adjacent to or separate from the bulk gas flow path, such as in a sampling passage or pathway that branches off from or is otherwise pneumatically connected or in fluid communication with the bulk gas flow path.

[0134] The flow therapy device 10 may include a patient sensor 26, such as a pulse oximeter or patient monitoring system, to measure one or more physiological parameters of the patient, such as the patient's blood oxygen saturation (SpO2), heart rate, respiratory rate, perfusion index, etc., and provide a measure of signal quality. The sensor 26 may communicate with the controller 13 via a wired connection or by communication via a wireless transmitter on the sensor 26. The sensor 26 may be a disposable adhesive sensor designed to be connected to the patient's finger. The sensor 26 may be a non-disposable sensor. Sensors designed for different age groups and to be connected to different locations on the patient are available and may be used with the flow therapy device. The pulse oximeter may be worn by the user, typically on the finger, although other locations such as the earlobe are also an option. The pulse oximeter is connected to a processor within the device and constantly provides a signal indicative of the patient's blood oxygen saturation. The patient sensor 26 may be a hot-swappable device and may be worn or replaced while the flow therapy device 10 is in operation. For example, the patient sensor 26 may be connected to the flow therapy device 10 using a USB interface or using a wireless communication protocol (e.g., Near Field Communication (NFC), WiFi, or Bluetooth). If the patient sensor 26 is disconnected during operation, the flow therapy device 10 may continue to operate in a previous operating state for a prescribed time period. After the prescribed time period, the flow therapy device 10 may trigger an alarm, transition from an automatic mode to a manual mode, and / or exit a control mode (e.g., automatic or manual mode) entirely. The patient sensor 26 may be a bedside monitoring system or other patient monitoring system that communicates with the flow therapy device 10 through a physical or wireless interface.

[0135] The flow therapy device 10 may include a high flow therapy device. Unless the context suggests otherwise, high flow therapy as discussed herein shall be given its typical and ordinary meaning as understood by those skilled in the art, which generally refers to a respiratory assistance system that delivers a target flow of humidified respiratory gas through an intentionally non-sealed patient interface, generally at a flow rate intended to meet or exceed the patient's inspiratory flow. Exemplary patient interfaces are non-sealed interfaces, including, but not limited to, nasal interfaces (e.g., cannula), tracheal interfaces, or oral interfaces. Typical flow rates for adults are often in the range of about 15 liters per minute (LPM) to about 70 liters per minute or more. Typical flow rates for pediatric patients (e.g., neonates, infants, children) are often in the range of about 1 liter per minute per kilogram of patient body weight to about 3 liters per minute per kilogram of patient body weight or more, but not limited to, high flow therapy may also include administration of a gas mixture composition including supplemental oxygen and / or a therapeutic drug.

[0136] By way of example only, high flow therapy is often referred to as nasal high flow (NHF), humidified high flow nasal cannula (HHFNC), high flow nasal oxygen (HFNO), hifh flow therapy (HFT), or tracheal high flow (THF), among other common names. By way of example only, the flow rates used to achieve "high flow" may be any of the following flow rates: For example, in some configurations, "high flow therapy" for an adult patient may refer to delivering gas to the patient at a flow rate of about 10 liters per minute (10 LPM) or greater, such as between about 10 LPM and about 100 LPM, or between about 15 LPM and about 95 LPM, or between about 20 LPM and about 90 LPM, or between about 25 LPM and about 75 LPM, or between about 25 LPM and about 85 LPM, between about 30 LPM and about 80 LPM, between about 35 LPM and about 75 LPM, or between about 40 LPM and about 70 LPM, or between about 45 LPM and about 65 LPM, or between about 50 LPM and about 60 LPM, etc. In some configurations, "high flow therapy" for neonatal, infant, or pediatric patients may refer to delivering gas to the patient at a flow rate greater than 1 LPM, such as between about 1 LPM and about 25 LPM, or between about 2 LPM and about 25 LPM, or between about 2 LPM and about 5 LPM, or between about 5 LPM and about 25 LPM, or between about 5 LPM and about 10 LPM, or between about 10 LPM and about 25 LPM, or between about 10 LPM and about 20 LPM, or between about 10 LPM and about 15 LPM, or between about 20 LPM and about 25 LPM. High flow therapy devices intended for adult, neonatal, infant, or pediatric patients may deliver gas to the patient at a flow rate between about 1 LPM and about 100 LPM, or any of the subranges above.

[0137] The flow therapy device 10 can deliver any concentration of oxygen (e.g., FdO2) up to 100% at any flow rate between about 1 LPM and about 100 LPM. In some configurations, any of the flow rates can be combined with oxygen concentrations (FdO2) of about 20%-30%, 21%-30%, 21%-40%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, and 90%-100%. In some combinations, the flow rate can be between about 25 LPM and 75 LPM combined with an oxygen concentration (FdO2) of about 20%-30%, 21%-30%, 21%-40%, 30%-40%, 40%-50%, 50%-60%, 60%-70%, 70%-80%, 80%-90%, 90%-100%. In some configurations, the flow therapy device 10 can include a safety threshold during manual mode operation that prevents a user from delivering too much oxygen to the patient.

[0138] High flow therapy can be administered to the user's nares and / or orally or via a tracheostomy interface. High flow therapy can deliver gas to the user at a flow rate that is equal to or greater than the peak inspiratory flow requirement of the intended user. High flow therapy can create a flushing effect in the nasopharynx such that the anatomical dead space in the upper airway is flushed by the high inflow gas flow. This can create a reservoir of fresh gas available for each breath while minimizing rebreathing of nitrogen and carbon dioxide. Meeting inspiratory demand and flushing the airway is also important when attempting to control the patient's FdO2. High flow therapy can be performed using a non-occlusive patient interface, such as a nasal cannula. A nasal cannula can be configured to deliver respiratory gas to the user's nares at a flow rate that is greater than the peak inspiratory flow requirement of the intended user.

[0139] As used herein, the term "non-sealing patient interface" or "unsealed interface" may refer to an interface that provides a pneumatic link between the patient's airway and a source of gas flow (such as from the flow generator 11) that does not completely occlude the patient's airway, unless the context suggests otherwise. In one configuration, the non-sealing pneumatic link may constitute an occlusion of less than about 95% of the patient's airway. In another configuration, the non-sealing pneumatic link may constitute an occlusion of less than about 90% of the patient's airway. In another configuration, the non-sealing pneumatic link may constitute an occlusion of between about 40% and about 80% of the patient's airway. The airway may include one or more of the patient's nostrils or mouth. In the case of a nasal cannula, the airway is through the nares.

[0140] The flow generator or blower 11 may include an ambient air inlet port 27 for drawing ambient room air into the blower. The flow therapy device 10 may also include an oxygen inlet port 28 that leads to a valve through which pressurized gas may enter the flow generator or blower 11. The valve may control the flow of oxygen to the flow generator blower 11. The valve may be any type of valve including a proportional valve or a binary valve.

[0141] The blower may operate at a motor speed of greater than about 1,000 RPM and less than about 30,000 RPM, greater than about 2,000 RPM and less than about 21,000 RPM, greater than about 4,000 RPM and less than about 19,000 RPM, or between any of the aforementioned values. The operation of the blower may mix the gas entering the blower through the inlet port. Because mixing requires energy, using the blower as a mixer may reduce pressure losses that may occur in systems with separate mixers, such as static mixers with baffles. The use of a static mixer also increases the volume of the gas flow path between the valve and the gas composition sensor, which may further increase the delay between when the valve current is changed and when a corresponding change in oxygen concentration is measured.

[0142] Based on user input and the therapy delivered by a particular device, the controller can determine target output parameters for the blower. The controller can receive measurements of the target output parameters, and based on the difference between the determined flow rate and the measured flow rate, the controller can adjust the speed of the blower.

[0143] The target output parameter may be a flow rate. The target flow rate may be a constant value (e.g., nasal high flow). The target flow rate may be a varying value. In some configurations, the controller may control the blower motor speed based on the target flow rate and may further increase or decrease the motor speed based on the patient's breathing cycle. The target flow rate does not necessarily change, but the controller may be configured to control the motor speed to vary in order to impart oscillations to the instantaneous flow rate so that the flow rate is synchronized with the patient's breathing. Such a system is described in PCT Publication WO 2017 / 200394, an international application entitled "Flow Path Sensing for Flow Therapy Apparatus," which is hereby incorporated by reference in its entirety.

[0144] The target output parameter may alternatively be a pressure. The target pressure may be a constant value, e.g., Continuous Positive Airway Pressure (CPAP). Alternatively, the target pressure may be a value that potentially varies with breathing, e.g., bi-level pressure therapy. In both of these scenarios, the total flow is unlikely to be constant.

[0145] With further reference to FIG. 1B, a sensing circuit board 2200 is shown that can be implemented in the flow therapy device 10. The sensing circuit board 2200 can be positioned in the sensor chamber such that the sensing circuit board 2200 is at least partially immersed in the gas flow. The gas flow can exit the blower 11, pass through a conduit, and enter a flow path in the sensor chamber. At least some of the sensors on the sensing circuit board 2200 can be positioned in the gas flow to measure gas properties within the flow. After the gas passes through the flow path in the sensor chamber, it can exit to the humidifier 12 as described above.

[0146] The sensing circuit board 2200 can be a printed sensing circuit board (PCB). Alternatively, the circuit on the board 2200 can be constructed with electrical wires connecting electronic components instead of being printed on a circuit board. At least a portion of the sensing circuit board 2200 can be mounted outside the gas flow. The gas flow can be generated by the flow generator 11 described above. The sensing circuit board 2200 can include an ultrasonic transducer 2204. The sensing circuit board 2200 can include one or more of thermistors 2205. The thermistor 2205 can be configured to measure the temperature of the gas flow. The sensing circuit board 2200 can include a thermistor flow sensor 2206. The sensing circuit board 2200 can include humidity sensors, including humidity-only sensors used with separate temperature sensors, and other types of sensors, such as combined humidity and temperature sensors, sensors for measuring air pressure, sensors for measuring differential pressure, and / or sensors for measuring gauge pressure. The thermistor flow sensor 2206 may comprise a hot wire anemometer, such as a platinum wire, and / or a thermistor, such as a negative temperature coefficient (NTC) or positive temperature coefficient (PTC) thermistor. Other non-limiting examples of heated temperature sensing elements include glass or epoxy encapsulated or unencapsulated thermistors. The thermistor flow sensor 2206 may be configured to measure the flow rate of the gas by being supplied with a constant power, or to be maintained at a constant sensor temperature or a constant temperature difference between the sensor and the gas flow. In one configuration of the respiratory apparatus, the sensing circuit board is positioned or disposed between the blower and the humidifier (i.e., near, partially within, or adjacent to the gas flow path extending between the blower and the humidifier). This is advantageous because a parameter or characteristic of the gas in the gas stream is sensed by one or more sensors on the sensing circuit board after the inlet gas (e.g., ambient air and oxygen and / or other auxiliary gas) is mixed. Additionally, sensing the parameter or property of the gas in front of the humidifier ensures that the humidified gas does not contact or interact with the sensor, thereby reducing the chance of condensation on or within the sensor.Additionally, sensing the gas stream prior to humidification may allow for more accurate and / or reliable sensor measurements.

[0147] The sensing circuit board 2200 can include a first portion 2201 and a second portion 2202. The first portion 2201 can be positioned to be in the gas flow path, while the second portion 2202 can be positioned to be outside the gas flow path. The direction of gas flow is indicated by arrow 2203 in FIG. 1B. The direction of gas flow can be straight or curved as shown in FIG. 1B.

[0148] Placing one or more of the thermistor 2205 and / or thermistor flow sensor 2206 downstream of the combined blower and mixer can account for heat provided to the gas flow from the blower. Also, immersing a temperature-based flow sensor in the flow path can increase the accuracy of the measurement because a sensor immersed in the flow is more likely to be exposed to the same conditions, such as temperature, as the gas flow, and therefore provides a better representation of the gas properties.

[0149] The sensing circuit board 2200 may include an ultrasonic transducer, transceiver, or sensor for measuring gas properties of the gas stream, such as the gas composition or concentration of one or more gases in the gas stream. Any suitable transducer, transceiver, or sensor may be attached to the sensing circuit board 2200, as will be appreciated. In this configuration, the sensing circuit board includes an ultrasonic transducer system (also referred to as an ultrasonic sensor system) that uses ultrasonic or acoustic waves to determine gas concentration. As will be appreciated, ultrasonic transducers may be used in gas composition sensing systems to sense the speed of sound through a gas stream by transmitting and receiving ultrasonic beams or pulses.

[0150] The ultrasonic transducer system may determine the relative gas concentrations of two or more gases in a gas stream. The ultrasonic transducer system may be configured to measure the oxygen fraction in a bulk gas stream consisting of atmospheric air supplemented with supplemental oxygen, which is essentially a binary gas mixture of nitrogen (N2) and oxygen (O2). It will be appreciated that the ultrasonic transducer system may also be configured to measure the gas concentrations of other supplemental gases blended with atmospheric air in the gas stream, including nitrogen (N2) and carbon dioxide (CO2). The ultrasonic transducer may determine the gas concentrations of the gases in the gas stream at relatively high frequencies. For example, the ultrasonic transducer may output FdO2 values ​​measured at the maximum sample rate of the sensor or at frequencies lower than the maximum sample rate, for example, between about 1 Hz and 200 Hz, between about 1 Hz and 100 Hz, between about 1 Hz and 50 Hz, and between about 1 Hz and 25 Hz.

[0151] In some configurations, the flow therapy device may also include a humidity sensor disposed in the flow path and configured to generate a humidity signal indicative of the humidity of the gas stream flowing through the sensor assembly. In such embodiments, the gas composition may be determined by the sensed speed of sound and the sensed temperature and / or sensed humidity of the gas stream. The humidity sensor may be a relative humidity sensor or an absolute humidity sensor. In some embodiments, the gas composition may be determined based on the sensed speed of sound and the sensed humidity without the need for a temperature sensor.

[0152] Ultrasonic transducer systems can be used to measure the respective ratios of any two known gases in a gas composition. Ultrasonic transducer systems can measure the relative gas concentrations in a mixture of air blended with supplemental oxygen, which is substantially equivalent to a nitrogen / oxygen mixture. In such a binary gas mixture, by monitoring the speed of sound and taking into account the temperature, the average molecular weight of the gases can be determined, and therefore the relative concentrations of the two gases. From this ratio, the oxygen or nitrogen fraction of the gas stream can be derived.

[0153] In some configurations, the flow therapy device can use flow beads to measure the total flow rate of the gas, as described in International Application Publication WO 2018 / 052320, entitled “Thermistor Flow Sensor Having Multiple Temperature Points,” which is incorporated herein by reference in its entirety. Flow beads may have the advantage of providing a more accurate measurement of flow rate, but may be slower to respond to sudden changes in flow (such as high frequency vibrations). Ultrasound transducers can measure sudden changes in flow, but may provide a less accurate overall measurement. In some configurations, the controller can generate a final measurement of the total flow rate by combining inputs from the flow beads and the ultrasound transducer, thereby enabling a measurement of flow rate that is both accurate and capable of detecting sudden changes in flow.

[0154] Some examples of flow therapy devices are disclosed in International Application Publication No. WO 2017 / 095241, entitled "Flow Path Sensing for Flow Therapy Apparatus," and International Application Publication No. WO 2016 / 207838, entitled "Breathing Assistance Apparatus," which are incorporated by reference in their entireties.

[0155] 3. Overview of predictive overheating alarm and control method Some exemplary embodiments of the predictive over-temperature alarm will now be described more specifically, by way of example only, in the context of a respiratory device in the form of a flow therapy device of the type described above, which provides high flow therapy and thereby respiratory assistance. As previously described, the alarm may also be adapted to other types of respiratory devices, including those capable of operating in multiple modes and / or providing multiple therapies. In one example, the alarm may be applied to a respiratory device capable of delivering both high flow therapy and pressure therapy depending on the selected mode of operation, and the alarm may function in both therapies or modes or operations. In one configuration, the controller of the device may be configured with different variations and / or versions of the alarm algorithm appropriate for each different mode of operation or therapy provided by the device, and may automatically apply or implement the version of the alarm algorithm appropriate for the current or selected mode of operation or therapy provided by the device.

[0156] A predictive over-temperature alarm is an algorithm, method or process implemented or executed by a main controller or sub-controller of the respiratory apparatus during operation of the respiratory apparatus. The predictive over-temperature alarm may be configured to predict whether at least one of the input settings or parameters applied to the respiratory apparatus for a therapy session can be applied or maintained without the steady state temperature of the apparatus exceeding a pre-defined elevated temperature condition (which may be for example a maximum temperature or a threshold parameter). As will be appreciated, a therapy session is typically a session or period of operation of the apparatus during which a user receives a flow of gas (e.g. typically humidified gas) from the apparatus having one or more particular flow characteristics.

[0157] In this example, the respiratory device is a flow therapy device and the primary input setting or parameter is a flow setting that determines the flow rate of the flow of gas delivered to the user during a therapy session. In this configuration example, the predictive over-temperature alarm is configured to predict whether a desired, current, or new therapy session set flow rate can be achieved and maintained without causing the steady state temperature of the device to exceed a predetermined maximum temperature or threshold. More specifically, the set flow rate corresponds to a blower motor speed and the controller determines whether the required motor speed (for the set flow rate) will raise the steady state temperature above a pre-set high temperature threshold.

[0158] In this exemplary configuration, in addition to the predictive overheat alarm, the device may have a device internal high temperature alarm. If the device internal temperature exceeds a threshold as measured by one or more internal temperature sensors, the high temperature alarm is triggered or issued. The one or more temperature sensors may include a temperature sensor on the sensing circuit board, or may be a temperature sensor located elsewhere in the housing of the device, such as, but not limited to, a temperature sensor at the outlet of the device, or a temperature sensor adjacent or proximate to the display screen of the user interface. If the device internal high temperature alarm is triggered based on the sensed temperature, this indicates that the device internal temperature is dangerous as it may damage other sensors, electronics, or other components.

[0159] The controller can be configured to automatically perform one or more actions or alarm responses when a device internal high temperature alarm is triggered. Below are various examples of one or more actions or alarm responses. When a device internal high temperature alarm is triggered, any combination of one or more of the following actions or alarm responses may be triggered or performed by the controller: The controller may automatically reduce the blower motor speed (and therefore the delivered or generated flow rate) to a level that reduces the internal device temperature. The controller may prompt or inform the user to change the size of the patient interface. For example, if the interface is a cannula or tracheal interface, the controller may prompt or inform the user to change to a larger cannula or larger tracheal interface because the current cannula or tracheal interface size provides too much resistance to flow, causing the motor speed to be too high for the set flow rate, resulting in an over-temperature condition. The controller may be configured to clear or reset a device internal high temperature alarm when the sensed temperature of the apparatus cools below a threshold value (which may be the same as or different from the alarm threshold temperature). The controller may be configured to reduce the heater plate temperature setpoint of the humidifier. This alarm response may reduce the humidity output of the gas stream, but may also generally reduce the thermal energy output from the heater plate to the device, thereby assisting in reducing the thermal energy and resulting temperature within the device. The controller presents a message or notification to the user via the user interface display to check for blockages in the gas flow circuit that may contribute to or cause an over-temperature condition. - The controller reverses the rotation of the blower to extract hot gases and expel them outside the unit to cool it down. - The controller will present the user with a general message or notification on the device's display indicating that the device internal high temperature alarm has been triggered. - The controller may shut down the device and stop the current operation or therapy.

[0160] With reference to FIG. 2, an overview of a predictive over-temperature alarm process flow or predictive alarm method 200 implemented by a controller of a respiratory device is described. The predictive alarm method 200 begins by receiving input data representing one or more input settings or parameters for a desired or new therapy session to be initiated, as shown at 202. By way of example, the input setting may be a set flow rate indicating a desired flow rate of gas flow delivered to a user of the device during a therapy session. The predictive alarm method 200 then predicts whether a steady state temperature of the respiratory device will exceed a high temperature condition threshold, as shown at 204, based on the input setting and / or one or more relevant operating parameters associated with the input setting. As an example, the controller may be configured to predict whether a steady state temperature of the respiratory device will exceed a high temperature condition threshold, based on a set flow rate input and / or a blower motor speed required to generate the set flow rate. If the predicted steady state temperature exceeds a pre-defined high temperature condition threshold, a predicted high temperature alarm or alarm signal is generated or triggered based on the prediction, as shown at 206. Optionally, in response to a generated alarm or alarm signal, the controller may be configured to initiate or activate one or more alarm responses, as indicated at 208 .

[0161] At step 204, the predictive alarm method 200 includes predicting a steady state temperature of or associated with the device based at least in part on a predetermined or dynamic thermal model. The thermal model represents one or more heat sources of or associated with the device. More specifically, the thermal model may represent heat generated by one or more components (heat sources) of the device in terms of thermal energy generated by the components that contribute to or cause an increase in the steady state temperature of the device as determined by the predictive over-temperature alarm. In one configuration, the thermal model represents at least heat generated by a blower of the flow therapy device as a function of motor speed and flow rate. In another configuration, the thermal model further represents heat generated by one or more non-blower heat sources of or associated with the device that contribute to the steady state temperature of the device. By way of example only, the one or more non-blower heat sources may include, but are not limited to, one or more of the following non-blower components or environmental variables of, connected to, or associated with the device: a battery or power source, a heater plate of a humidifier, a heater wire of a patient interface conduit, an electronic circuit or component, a printed circuit board (PCB), a graphical user interface, a display screen, and / or ambient conditions of the environment surrounding the device (such as, but not limited to, ambient temperature and / or ambient humidity).As will be appreciated, the thermal model may be configured to model heat sources in terms of a measure of temperature (such as, but not limited to, Celsius or Fahrenheit) and / or a measure of thermal energy (such as, but not limited to, Joules or other SI units of energy).

[0162] In a first form, the thermal model may be based, at least in part, on a theoretical thermal model of the device. For example, the theoretical thermal model may be a computer or mathematical or scientific model or calculation of how one or more heat sources in or associated with the device may contribute to the steady state temperature of the device. In a second form, the thermal model may be based, at least in part, on an empirical thermal model of the device based on empirical thermal data associated with the operation of the device, for example, through experimental testing. The empirical thermal data may be based on recorded or stored temperature data measured or sensed, for example, over one or more operating ranges, conditions, and / or treatment sessions during use of the device or during experimental testing. In a third form, the thermal model may be based, at least in part, on one or more predetermined or configurable safety values. For example, the thermal model may take into account one or more heat sources, such as the ambient temperature or heat generated by a heater element or such component, and may assign those parameters or components a safe heat value that represents a likely or realistic upper limit on the maximum heat that they may each contribute to the steady state temperature of the device during operation. Any of the above thermal models may be stored or preserved in a memory of the controller of the device. As will be appreciated, the thermal model may be represented as a mathematical function, a look-up table, or any other suitable computable format.

[0163] Predicting a steady state temperature of or associated with the device based on the thermal model in step 204 includes the control determining a blower motor speed required to generate an input set flow rate target for the treatment session and using the determined motor speed as an input or variable into the thermal model to generate a predicted steady state temperature of the device. In some device configurations, the controller is configured to determine the motor speed required to generate the set flow rate based on a stored known relationship or model or function of motor speed and flow rate, or by extracting or extrapolating that data from it.

[0164] In other configurations, the controller is configured to determine the motor speed required to produce the input set flow rate by increasing or varying the blower motor speed until the set flow rate is produced, such that the required motor speed is determined in real-time or dynamically for the particular device and current operating variables. Determining the required motor speed in real-time or dynamically in this manner allows the controller to take into account current device configuration characteristics and / or parameters for an individual user, such as the type and configuration of the patient interface being used, the type and characteristics of the patient interface conduit being used, and / or other parameters or characteristics of the device being operated that may affect the relationship between motor speed and the flow rate produced.

[0165] The predictive alarm method 200 is executed by the controller whenever a new set flow rate input is received by a user, which typically occurs when a new treatment session is initiated for a user or when the set flow rate is changed or modified during a treatment session. The flow therapy device may initiate a new treatment session from a start-up or standby mode where the blower is stopped or idling at a non-therapeutic speed, or the device may be switched to a new desired treatment session or a changed or new set flow rate while the device is already operating in a current treatment session. In either scenario, the predictive alarm method 200 is executed by the controller in response to receiving an input of a new or updated set flow rate associated with the desired treatment session and determines whether the predicted steady state temperature of the device will exceed the high condition threshold based on those new or updated input settings and / or parameters associated with the new desired treatment session.

[0166] The predictive alarm method 200 may be configured to predict or determine future steady state temperatures of interest of, in, or associated with a device. The type or nature of the steady state temperatures of interest may depend on the required purpose or goal of the alarm. A predictive alarm is configured to predict steady state temperatures that represent sustained and / or stable temperature parameters, as opposed to transient temperature parameters. For example, a predictive alarm is directed to predicting whether temperature aspects of a device will remain in an undesirable and / or unsafe over-temperature zone for an undesirable and / or unsafe period of time, as opposed to predicting whether temperature aspects will temporarily spike into an unsafe zone in the future. A predictive alarm is primarily directed to raising an alarm when, depending on the particular steady state temperature of interest, a device, an area within a device, a component of a device, or a parameter associated with the device or its operation is predicted to experience a sustained period of high heat (e.g., an overheated or over-temperature condition) that is in some way harmful to the device and / or a user.

[0167] As an example, in one configuration, the predictive alarm can be configured such that the steady state temperature predicted by the alarm method represents a predicted temperature parameter of the device after operating at the set flow rate for at least a predetermined minimum period of time. In other words, in one configuration, the predicted steady state temperature determined by the alarm method represents a likely settled or long-term average temperature of the device. This period of time can be such that the steady state temperature represents a sustained and / or stable temperature parameter, e.g., once the device has settled into a relatively stable operating condition, as opposed to being in a "start-up" state where at least some components may not have reached a long-term operating temperature and / or condition for a therapy session.

[0168] As mentioned above, the predictive alarm may be configured such that the steady state temperature for which the alarm is directed may be any desired temperature parameter of, within or associated with the respiratory apparatus.

[0169] In one configuration, the steady state temperature for the predictive alarm can be configured to represent a predicted temperature of the gas stream in the device at a specified region or location within the gas flow path of the device. For example, in this configuration, the steady state temperature may represent a predicted temperature of the gas stream after the humidifier and / or at or near the outlet of the device that connects to the patient interface conduit, or may represent a predicted temperature of the gas stream in the region of one or more sensors and / or sensing circuits or PCBs of the device.

[0170] In another configuration, the steady state temperature of the predictive alarm can be configured to represent a predicted temperature in a particular location or area of ​​the main housing of the device, or in a region or areas of a particular component or component of the device. By way of example only, the device may be configured such that the steady state temperature represents a predicted temperature in any one of the following selected locations or areas: - in a central area or zone of the housing of the device, - Places or areas close to the equipment blowers, - Locations or areas close to electronic circuits or PCBs of the device; - Locations or areas near a display screen or user interface components of the device; - Locations or areas near the humidifier or humidifier components of the device; or - A location or area proximate to a particular component, such as a sensor or sensing circuit. By way of example, the sensor or sensing circuit may comprise any one or more of a flow sensor, a temperature sensor, a pressure sensor, a humidity sensor, an ultrasonic sensor, etc., which may be temperature sensitive in their accuracy or sensitivity or may only operate reliably within a particular operating temperature range.

[0171] In another configuration, the steady state temperature of the predictive alarm can be configured to represent a predicted general overall temperature parameter associated with the apparatus based on a thermal model of the apparatus and / or one or more heat sources of interest or associated with the apparatus. For example, in this configuration, the steady state temperature can represent a theoretical or overall temperature parameter that is not specific to a particular location, area, or component of the apparatus, but is a general temperature parameter that represents the total temperature or heat within or associated with the apparatus or device.

[0172] In general, the purpose of a predictive over-temperature alarm is to predict (i.e., predetermine a future condition) of a high temperature condition that will cause a temperature rise (or high fever) in the device. In other words, the predictive alarm is configured to predict whether a desired operation (e.g., treatment setting) of the device will cause the steady state temperature of the device to exceed a high temperature threshold in the future. If the high temperature condition persists, it may cause errors, malfunctions, or damage to the sensor. Additionally or alternatively, high temperatures may cause an increase in the temperature or enthalpy of the gas stream, which may be unsafe for the end user. In some cases, a temperature that is too high may damage components of the device. For example, a sustained high temperature may damage the blower or the gas flow path through the device (i.e., pipes, connections, couplings, and / or seals).

[0173] The predictive alarm method 200 compares the predicted steady state temperature to a predefined high temperature threshold. The high temperature threshold may be a data value or variable stored in a memory associated with the controller. The high temperature threshold may be a configurable temperature parameter, such as a temperature value. The high temperature threshold may be a temperature parameter that is pre-determined or selected based on the characteristics of the device and / or the particular type of steady state temperature predicted for the alarm. For example, the high temperature threshold may depend on the particular temperature parameter that the predicted steady state temperature represents. For example, a threshold for a predicted steady state temperature representing the temperature of a gas flow may be different (higher or lower) compared to a threshold for a predicted steady state temperature representing the temperature of a particular location of the housing of the device.

[0174] As a further example, in one configuration, the steady state temperature represents a predicted temperature parameter related to the temperature of the gas flow at a specified region or location within the device. In this configuration, the high temperature threshold can be configured to represent a gas temperature safety threshold or value beyond which there is increased risk of malfunction, device damage, and / or safety to the user associated with or caused by overheating of that gas flow. In another configuration, the steady state temperature can be configured to represent a predicted temperature parameter for a particular location or region within a main housing of the device, and the high temperature threshold can be configured to represent a housing temperature safety threshold or value beyond which there is increased risk of malfunction, device damage, and / or safety to the user associated with or caused by overheating of that location or region of the main housing.

[0175] At step 206, the predictive alarm method 200 is configured to generate an alarm signal or a predicted high temperature condition signal if the predicted steady state temperature exceeds the high temperature condition threshold. At step 208, the predictive alarm method 200 is configured to trigger or initiate one or more alarms or alarm responses in response to the alarm signal or high temperature condition signal.

[0176] In one configuration, the alarm response may include generating an alarm notification, which may be any one or more of an audible, visual, tactile, and / or haptic alarm. As an example, the alarm notification may include the controller displaying an alarm message, notification, or indication on a display screen or user interface of the device.

[0177] In some configurations, the controller is configured to overrule the set flow rate and disable the motor or slow the motor to idle speed if an alarm occurs.

[0178] In some configurations, the controller is configured to limit or reduce the motor speed to a maximum allowable motor speed if an alarm occurs and generate an alarm message, notice, or indication on a display screen or user interface of the device. In such configurations, the maximum allowable motor speed may represent the highest motor speed that the device can maintain for a set flow rate without causing the steady state temperature to exceed the high condition threshold.

[0179] In some configurations, the controller is configured to reduce or disable the power applied to or operation of one or more non-blower components of the device to reduce their heat output if an alarm occurs. In one example, the controller may be configured to reduce the power applied to and / or disable a heater plate of a humidifier and / or a heater wire of a patient interface conduit (e.g., a respiratory tube) if an alarm occurs. In another example, the controller is configured to reduce or disable a charging circuit associated with a battery of the device if an alarm occurs.

[0180] It will be appreciated that the controller may actuate any one or more of the exemplary alarm responses listed above in response to the alarm signal. As will be appreciated, an alarm response does not necessarily always have to trigger an alarm notification (such as a visual, tactile, and / or audible alarm). As noted above, an alarm response performed by the controller may be to control an apparatus in a particular manner to address and / or avoid a predicted future over-temperature condition, such as by changing or modifying an operating setting or parameter, as described above. This may be done alone or in combination with generating an alarm notification.

[0181] The above general description of the predictive over-temperature alarm 200 algorithm or process steps is generally applicable to the following first and second exemplary embodiments, which provide example implementations and / or configurations of the overall alarm method 200. The first and second exemplary embodiments illustrate direct and indirect implementation methods of assessing or predicting whether the steady state temperature of a device will exceed a predetermined overtemperature threshold.

[0182] As will be appreciated, the predictive overheat alarm algorithm and / or process is executed by a controller or processor of the device. The alarm algorithm and / or process can be programmed as software or computer readable instructions executable by the controller or processor of the device. As will be appreciated, the necessary input signals and / or data (e.g., sensor signals and / or operational or treatment settings and / or user control inputs to the device) used by the alarm algorithm can be acquired or received by the controller. Similarly, the output or alarm response generated by the alarm algorithm can be executed by the controller via control signals, etc. It will also be appreciated that the associated thermal model utilized by the alarm algorithm can be stored in, retrieved from, and / or coded in the software algorithm, electronic memory accessible by the controller.

[0183] 4. First Exemplary Embodiment - Predictive Over-Temperature Alarm Based on Motor Speed ​​Estimation overview 3-4C, a first exemplary embodiment of a predictive over-temperature alarm 300 is described in further detail. The predictive over-temperature alarm 300 in this first embodiment utilizes an indirect alarm prediction based on comparing the motor speed required for the set flow input of a treatment session with an estimated maximum allowable motor speed representing a speed at which there is a significant risk of the steady state temperature of the device exceeding a predetermined high temperature condition. Briefly, a controller or processor determines a maximum allowable motor speed value (for the current set flow rate) above which there is a significant risk of the steady state temperature of the device exceeding a predetermined maximum value.

[0184] In one configuration, the alarm algorithm determines or extracts the motor speed required for the set flow rate by allowing the device controller to control the blower motor speed to generate the set flow rate using the closed loop feedback control described above. Once the motor speed required to generate the set flow rate is known, it is then compared to a predicted maximum allowable value. If the required motor speed exceeds this maximum allowable value (to achieve the current set flow rate), the processor immediately initiates an alarm response without waiting for the device to actually heat up and exceed a predetermined maximum steady state temperature. In one embodiment, the alarm response initiated is for the controller to return the motor speed to the maximum allowable motor speed limit as determined by the predictive overheating alarm algorithm. This limits the flow rate of the gas flow below the target set flow rate, which may trigger a "flow rate below target" alarm. In other embodiments, the alarm algorithm may implement any one or more of the other alarm responses described above.

[0185] In another configuration, the predictive over-temperature alarm is configured to determine or predict a maximum allowable motor speed value for a set flow rate input for a treatment session, above which it is predicted that there is a significant risk of the steady state temperature of the device exceeding a predetermined maximum value or threshold. In this configuration, rather than determining a required motor speed for a set flow rate and comparing it to a predicted limit value, the predictive over-temperature alarm operates the controller to set or limit the motor speed of the blower during a treatment session for a set flow rate input setting to a predicted maximum allowable motor speed limit value such that the motor speed does not exceed the limit value during closed loop feedback control of the blower. In this configuration, the predictive over-temperature alarm operates as a control algorithm or provides a limit input to the blower control so that the maximum allowable motor speed cannot be exceeded.

[0186] In this embodiment, the controller is configured to predict whether the steady state temperature will exceed the hot condition threshold based on a determination of whether the motor speed required for the set flow rate input exceeds the maximum allowable motor speed. The controller determines a maximum allowable motor speed, which indicates the highest motor speed that the device can maintain for the set flow rate without causing the steady state temperature to exceed the hot condition threshold. In this embodiment, the maximum allowable motor speed is based on or is a function of a predetermined thermal model. In effect, the maximum allowable motor speed for the set flow rate represents the hot condition threshold.

[0187] In this embodiment, the thermal model is a function or threshold representing the maximum allowable motor speed for a range of set flow rates, the thermal model being generated based at least in part on the high temperature condition threshold. As will be appreciated, the threshold may be defined by an equation or function that defines a limit or threshold as a function or function of the motor speed and / or flow rate, and the threshold may be encoded in software code in the controller or memory accessible by the controller. The threshold may be represented graphically as a line (straight or curved) on a plot or graph, such as those depicted in Figures 4A and 4B and described below.

[0188] In one configuration, the thermal model represents heat generated by the blower, which is a function of flow rate and motor speed. In another configuration, the thermal model represents heat generated by the blower, which is a function of flow rate and motor speed, and one or more non-blower heat sources. In one form, the thermal model can be configured to represent one or more non-blower heat sources with respective preset values ​​representing the maximum amount of heat that can realistically be generated by each of the one or more non-blower heat sources during operation. In another form, the thermal model can be configured to represent one or more non-blower heat sources with one or more respective preset or configurable safety values ​​representing the maximum amount of heat predicted to be generated by each of the heat sources in a desired treatment session.

[0189] In one configuration, the thermal model is configured to model the heat (energy) and / or temperature rise caused by one or more heat sources in the device. In particular, the thermal model is configured to model the heat generated by one or more heat sources in the device, and then models the temperature rise that occurs or may occur in the device as a result of this heat being present and / or flowing through the device. The determination of the maximum allowable motor speed for a set flow rate input from the thermal model can be considered a reordering of the thermal model. In one configuration, the thermal model involves or includes calculating the temperature rise based on modeling the thermal energy of one or more heat sources in the device.

[0190] In one configuration of this embodiment, the maximum allowable motor speed for a flow range is represented or defined by a predetermined threshold line plotted on a motor speed versus flow graph. The area above the threshold line represents the hot condition zone. In this configuration, the controller is configured to predict whether the steady state temperature will exceed the hot condition threshold by determining whether a combination of the required motor speed and set flow rate is in the hot condition zone.

[0191] Exemplary Implementation Process Next, a more detailed implementation of the predictive over-temperature alarm 300 of the first embodiment will be described.

[0192] 3, the predictive alarm process performed by the controller of the device begins by receiving or obtaining a set flow rate input for a new or desired treatment session, or receiving an updated or changed set flow rate input or setting for a current treatment session, as shown at 302. As previously mentioned, in this embodiment the predictive alarm algorithm is implemented as software code, such as computer readable instructions executable by a processor within the controller or device.

[0193] The controller then estimates a first amount of heat representing the heat contributed to the steady state temperature by one or more non-blower heat sources, as shown at 304. As an example, the controller estimates the heat that may be added to the device if the temperature of one or more predetermined or selected non-blower components (e.g., backup battery, heater plate of humidifier) ​​in the device were to rise to their realistic maximum value and / or if heat from environmental sources (e.g., ambient air) were to rise to their realistic maximum value. In one form, the alarm algorithm stores fixed individual maximum heat or temperature rise values ​​associated with one or more non-blower components for use in the thermal model. In some configurations, the predictive alarm 300 may be configured to account for all or at least a majority of the non-blower heat sources in and / or associated with the device. It will be appreciated that the predictive alarm 300 need not necessarily account for heat energy from all non-blower components and / or environmental variables, but may account for at least one or more of the significant non-blower heat sources that contribute a majority of heat to the device during operation.

[0194] In alternative embodiments, instead of using fixed, predetermined realistic maximum values, the algorithm may use real-time determined temperature and / or operating values ​​for some non-blower heat sources, for those that are deemed stable over a treatment session. For example, any one or more of the following real-time values ​​may be used to represent the non-blower heat sources in the thermal model: real-time temperature sensor values ​​of the device, humidifier heater plate power or current, heated breathing tube power or current, and / or battery power or current, depending on which non-blower components are used in the thermal model. To further explain, the device may have one or more temperature sensors, such as an ambient temperature sensor, and some of the non-blower components (e.g., humidifier heater plate, heated breathing tube, battery) may have temperature sensors associated with them to sense their temperatures. In some configurations, these sensed temperatures may be provided in real-time to the predictive alarm algorithm as an alternative to a thermal model using predetermined maximum temperature values ​​of one or more non-blower components in the thermal model.

[0195] The controller then estimates a maximum allowable motor speed for the blower corresponding to a second amount of heat representing the heat contributed by the blower to the steady state temperature such that the sum of the first amount of heat and the second amount of heat does not cause the steady state temperature to exceed the high temperature threshold, as shown at 306. As an example, in one configuration, the relationship between the motor speed-flow rate combination and the heat likely to be generated by the blower is known for the device and stored in the controller's memory or accessible by the controller. In general, the higher the motor speed required to achieve a given set flow rate, the more heat will be generated by the blower. Using this known and stored relationship, the controller estimates the maximum motor speed that can be maintained (for the current set flow rate) without causing the steady state device temperature to exceed a maximum value (the predefined high temperature threshold) due to the sum of the heat generated by the blower (the second amount of heat) and the heat generated by non-blower components and environmental variables (the first amount of heat).

[0196] In another configuration, steps 304 and 306 may be combined. In particular, the alarm algorithm may use a stored thermal model (e.g., an equation or function) that represents a merged or combined model of the heat energy and / or temperature rise caused by one or more non-blower components and the blower, relative to the set flow input. As noted above, maximum heat or temperature rise may be estimated in the model of the non-blower components, and they may be expressed as individual or composite variables that vary the heat generation or temperature rise based on the set flow input.

[0197] Once the maximum motor speed is determined, the controller is configured to increase or vary the blower motor speed to the motor speed required for the blower to produce or achieve the set flow rate, as shown at 308. In particular, the controller uses a closed loop control that uses a flow rate sensor and / or a motor speed sensor to vary the motor speed to achieve the set flow rate. This allows the controller to dynamically determine the motor speed required for a set flow rate input. As will be appreciated, depending on the configuration of the device and / or the components used (e.g., type of patient interface), the specific motor speed required to produce a set flow rate may vary from device to device or user to user, and is therefore more accurately determined dynamically in real time. In another configuration, a model or estimate of the relationship between motor speed and flow rate may be stored in the controller, and this model may be used to derive the required motor speed for a set flow rate input, rather than dynamically determining the required motor speed, although it will be appreciated that the model output will be an estimate.

[0198] Once the required motor speed is determined (whether dynamically determined or estimated), the controller then predicts whether the steady state temperature of the device will exceed an over-temperature threshold based on the determined maximum allowable motor speed and the determined required motor speed, as shown at 308. In particular, if the required motor speed exceeds the maximum allowable motor speed, it is predicted that the steady state temperature of the device will at some stage exceed a pre-defined over-temperature threshold and an alarm is triggered at 310. As previously described, in response to the alarm being triggered, the controller may initiate one or more alarm responses to combat or avoid the predicted over-temperature condition.

[0199] Thermal Model 4A-4C, an example thermal model configuration utilized in the predictive over-temperature alarm 300 of the first embodiment will now be described in further detail.

[0200] As described, at the start of a new treatment session, or if the set flow rate is changed during a treatment session, or if the device is stopped and then restarted during a treatment session, the controller runs a predictive overtemperature algorithm to predict whether the new or updated set flow rate can be achieved and maintained without causing the steady state temperature of the device to exceed a predetermined maximum (the overtemperature threshold).

[0201] The predictive alarm 300 algorithm enables the controller to predict the

number

number

number

[0202] As mentioned above, the steady-state temperature of the device is T max Heat from the blower is not the only factor that can contribute to exceeding T. For example, heat from the battery power source and from the surrounding environment can also contribute, as well as other heat sources selected as important to be included in the thermal model. As the temperature of the battery, the surrounding environment, and other selected heat sources increases, T max Therefore, less heat can be generated by the blower before ω max An example of a more complete formula or thermal model for determining is as follows:

number

[0203] Referring to FIG. 4C, the predictive alarm algorithm implemented by the controller is based on, or as a function of, the thermal model, and determines the ω max The algorithm then determines whether the required or current motor speed for that set flow rate is equal to ω max Determine whether the required motor speed is beyond the ω max If the temperature exceeds the T curve, the controller determines whether the steady state temperature of the device exceeds T during the treatment session, as shown at 322. max If the required motor speed exceeds ω, an alarm is triggered. max If the temperature is below the curve, the controller determines whether the steady state temperature of the device will reach T during the treatment session, as shown at 324. max is not expected to exceed this threshold and will not trigger an alarm.

[0204] It will be appreciated that the values ​​of the non-blower heat sources included in the more complete thermal model (2) may be fixed, predetermined values, as described above, or in other configurations may be dynamic variables that are determined in real time to update the thermal model during operation. For example, in some configurations some components and / or variables may be determined in real time, particularly those that are deemed likely to remain stable throughout a treatment session. For example, T ambient The value of may be determined by an ambient temperature sensor on the device or an ambient temperature sensor operatively connected to the device, and the sensed ambient temperature may be used in the thermal model when this ambient temperature is likely to be relatively stable throughout a treatment session, which may be the case in a usage scenario where the device is used in a climate-controlled room or environment. Similarly, other non-air-blowing heat source components of the device in the thermal model may be determined in real time by temperature sensors associated with the components of the device, and the thermal model may be updated during operation of the device.

[0205] The more complete thermal model (2) described above, which considers not only the blower heat source but also one or more other non-blower heat sources of or associated with the device, is provided solely by way of example. It will be appreciated that the thermal model can be configured to consider any desired one or more of the non-blower heat sources or components of or associated with the device. In one configuration, the thermal model can be configured to model all or at least a majority of the significant heat sources associated with the steady state temperature of interest for predictive alarms, and in other configurations, the thermal model can be configured to consider one or more selected heat sources. The thermal model can be customized and / or configured based on a variety of factors, including, but not limited to, one or more of the specific configuration and characteristics of the device, the operating mode of the device, peripheral components connected to the device such as patient interface conduits and / or interfaces (cannulas, masks, etc.), and / or the desired sensitivity and / or safety factor desired for the predictive alarms.

[0206] 5. Second Exemplary Embodiment - Determining Whether the Predicted Steady State Temperature of the Device Exceeds the High Condition Threshold overview A second exemplary embodiment of the predictive over-temperature alarm 400 is described in further detail with reference to Figures 5-6B. The predictive over-temperature alarm 400 in this second embodiment utilizes direct alarm prediction where the steady state temperature of the device is predicted and compared to a maximum device temperature (overheat threshold). In this second embodiment, the controller or processor predicts the highest steady state temperature the device can reach given the current set flow rate and the motor speed required to achieve it. If this predicted steady state temperature exceeds a predetermined maximum temperature (overheat threshold), the controller immediately activates the alarm without waiting for the device to actually heat up and exceed its maximum steady state temperature.

[0207] In this embodiment, the controller is configured to predict whether the steady state temperature will exceed the high temperature threshold based on predicting the steady state temperature as a function of the required motor speed and the set flow rate, and determines whether the predicted steady state temperature exceeds the high temperature threshold.

[0208] In this embodiment, predicting the steady state temperature includes extracting an estimate from a predefined thermal model. In one configuration, the thermal model represents heat generated by the blower, which is a function of flow rate and motor speed. In another configuration, the thermal model represents heat generated by the blower, which is a function of flow rate and motor speed, and one or more non-blower heat sources. In one form, the thermal model can be configured to represent one or more non-blower heat sources with respective preset values ​​representing a maximum amount of heat that can realistically be generated by each of the one or more non-blower heat sources during operation. In another form, the thermal model can be configured to represent one or more non-blower heat sources with one or more respective preset or configurable safety values ​​representing a maximum amount of heat predicted to be generated by each of the heat sources in a desired treatment session.

[0209] In this embodiment, the controller is configured to predict whether the steady state temperature of the device will exceed the high temperature threshold by predicting the steady state temperature based on or as a function of a predetermined thermal model, a set flow rate, and a required motor speed. The controller then determines whether the predicted steady state temperature exceeds the high temperature threshold. In one configuration, the thermal model can generate a temperature variable representing the predicted steady state temperature based at least on the set flow rate and the required motor speed, such that the thermal model is based at least on heat generated by the blower. In another configuration, the thermal model generates a temperature variable representing the predicted steady state temperature based at least on the set flow rate, the required motor speed, and one or more other parameters representing non-blower heat sources of the device or associated with the device that contribute to the steady state temperature of the device. In either configuration, the controller is configured to determine whether the temperature variable representing the predicted steady state temperature exceeds the high temperature threshold and generates an alarm if the threshold is exceeded.

[0210] Exemplary Implementation Process A more detailed example of the implementation of the predictive over-temperature alarm 400 of the second embodiment will now be described.

[0211] Referring to FIG. 5, the predictive alarm process executed by the device's controller begins, as shown at 402, by receiving or obtaining a set flow rate input for a new or desired therapy session.

[0212] The controller then increases or changes the blower motor speed to the motor speed required for the blower to produce or achieve the set flow rate, as shown at 404. This step is similar to that described in 308 with respect to the first embodiment, and the same options and configurations are applicable to this embodiment.

[0213] Once the required motor speed for the set flow rate is determined, the controller is then configured to estimate a first steady state temperature value or component representing the heat contributed to the steady state temperature by the blower alone, as shown at 406. As an example, a relationship between the motor speed-flow rate combination and the heat likely to be generated by the blower is known for the device and stored in memory or accessible by the controller. In general, the higher the motor speed required to achieve a given set flow rate, the more heat will be generated by the blower. Using this known and stored relationship and the current motor speed-flow rate combination, the controller estimates the steady state temperature that the device would reach if the blower was the only heat source.

[0214] The controller is then configured to estimate a second steady state temperature value or component, as shown at 408, representing heat contributed to the steady state temperature by one or more non-blower heat sources. As an example, the controller estimates how far the steady state temperature of the device could increase (above the temperature estimated from the first steady state temperature value at 406) if one or more non-blower heat sources (e.g., humidifier heater plate, backup battery, ambient air) were increased to a realistic maximum value. It will be appreciated that the predictive alarm 400 does not necessarily need to consider heat energy from all non-blower components and / or environmental variables, but may consider at least one or more of the significant non-blower heat sources that contribute a majority of heat to the device during operation. In an alternative embodiment, instead of using a fixed predetermined realistic maximum value, the algorithm can use real-time determined temperature values ​​for some non-blower heat sources that are considered to be stable over a treatment session.

[0215] The controller predicts a steady state temperature of the device by aggregating or summing the first steady state temperature value and the second steady state temperature value, as shown at 410. The controller then triggers a predictive alarm if the predicted steady state temperature exceeds an overheating condition threshold, as shown at 412. As previously described, in response to the alarm being triggered, the controller can initiate one or more alarm responses to combat or avoid the predicted overheating condition.

[0216] Thermal Model 6A and 6B, the thermal model configuration utilized in the predictive over-temperature alarm 400 of the second embodiment will now be described in further detail by way of example.

[0217] flow rate

number

number

[0218] Referring to FIG. 6A, the set flow rate

number

number

[0219] The predictive alarm 400 allows the controller to predict how much the steady state temperature of the device may rise above a first steady state temperature T1 during a therapy session (without changes in flow rate or motor speed). This temperature rise (ΔT) may be caused by other non-blower heat sources, such as but not limited to the battery and ambient air, or any of the other non-blower heat sources mentioned above. Thus, the thermal model may express this second steady state temperature value associated with the non-blower heat source as: ΔT = f(T ambient , T battery , ...T other heat sources )

[0220] In one configuration, as described above, the predictive alarm algorithm 400 is ambient , T battery , ...T other heat sources We preset the value of to a realistic maximum value to obtain a conservative worst-case scenario value for ΔT.

[0221] Once T1 and ΔT have been determined, the algorithm allows the controller to calculate their sum, which represents the predicted highest steady-state temperature the device may reach during a treatment session (taking into account all possible heat sources considered in the thermal model), as the maximum allowable device temperature, T max 6B, the predictive alarm algorithm 400 can be used to compare the steady state temperature prediction, represented by the sum of T1 and ΔT, with the high temperature threshold T maxIf the controller determines that the predicted steady state temperature is greater than the threshold, then the controller triggers an alarm, as shown at 432. If the controller determines that the predicted steady state temperature does not exceed the threshold, then no alarm is triggered, as shown at 434.

[0222] 6. Third Exemplary Embodiment - Pressure Therapy Device with Predictive Over-Temperature Alarm The above embodiments describe the implementation of a predictive over-temperature alarm in the context of a respiratory device that is a flow therapy device or is operable in a flow therapy mode. As previously mentioned, the principles of predictive over-temperature alarms can also be implemented in other types of respiratory devices or in different therapy modes.

[0223] By way of example, implementation of a predictive over-temperature alarm will now be described in the context of a respiratory device in the form of a pressure therapy device or a respiratory device operating in a pressure therapy mode. By way of example, such pressure therapy modes include, but are not limited to, continuous positive airway pressure (CPAP), bilevel positive airway pressure (BiPAP), bubble CPAP (BCPAP), and non-invasive ventilation (NIV). It will be appreciated that the theory and operating principles described from the previous embodiments may be applied and adapted to a pressure therapy device, as will be further described below.

[0224] In a pressure therapy device (or when a respiratory device is operating in a pressure therapy mode), the user selects or inputs one or more target pressure settings for the pressure of the gas stream delivered to the user in a therapy session via a sealed patient interface, such as a full face mask. The one or more pressure settings may be, for example, a single pressure setting for CPAP therapy, or an inspiratory pressure setting and an expiratory pressure setting for BiPAP therapy. A controller implementing a predictive over-temperature alarm determines the blower motor speed or range of motor speeds required to achieve one or more set pressure levels. Using any of the thermal models described above in the former embodiment, the predictive alarm algorithm then predicts whether an over-temperature condition will occur in which the steady state temperature of the device will exceed a high temperature threshold condition, and initiates one or more alarm responses if the current pressure or operating setting is predicted to exceed the threshold at some point in the future.

[0225] In one configuration, the predictive over-temperature alarm calculates a maximum allowable motor speed or motor speed range based on the thermal model and pressure setting that, if exceeded, would predict that the steady state temperature of the device would exceed a high temperature threshold condition. The controller then treats the determined allowable motor speed or motor speed range as a threshold or limit and limits the blower motor speed from exceeding the allowable motor speed threshold or limit during a pressure therapy session to avoid an over-temperature condition of the device.

[0226] In another configuration, the predictive over-temperature alarm may calculate a maximum allowable motor speed or motor speed range based on the thermal model and pressure settings as described above, and may issue an alarm or initiate an alarm response if the measured or sensed blower motor speed exceeds the maximum allowable motor speed limit for a predetermined period of time. The predetermined period of time may be selected or determined to correspond to when the steady state temperature is about to exceed an overtemperature threshold condition.

[0227] It will be appreciated that a respiratory device may be configured and operable in one or more therapy modes. For example, a respiratory device may be selectively operable to provide flow therapy, such as nasal high flow therapy, and / or pressure therapy, such as CPAP, BiPAP, BPAP, etc. In such devices, a predictive over-temperature alarm may be implemented in any one or more or all of these therapy modes.

[0228] 7.Overheating detection system for breathing apparatus In any of the exemplary embodiments of the respiratory apparatus described above, whether flow therapy, pressure therapy, or both, the apparatus may also be configured with a system for detecting an actual over-temperature condition during operation, this actual over-temperature detection system being in addition to and independent of the predictive over-temperature alarm algorithm.

[0229] As an example, an over-temperature detection system for a respiratory device is configured to monitor the device's internal temperature via one or more temperature sensors in the device. If any one or more of the temperature sensors exceed an associated over-temperature threshold, an alarm is triggered or activated. In one configuration, the alarm generates a notification or message and displays it on a display screen of the device. For a flow therapy session, the alarm notification may indicate that the target flow rate is too high, indicating that operation of the device at the current flow setting has caused the device's internal temperature to exceed a safety threshold or high temperature condition. As an example, an alarm may be triggered if the temperature is sensed to be equal to or greater than a first temperature threshold during a first time period, or equal to or greater than a second temperature threshold during a second time period, where the first temperature threshold is lower than the second temperature threshold and the first time period is longer than the second time period. For example, an alarm may be configured to be triggered if the sensed temperature is 70° C. for 60 seconds, or greater than 85° C. for 10 seconds. It will be appreciated that there may be multiple cascading temperature thresholds and corresponding time periods, with higher thresholds having shorter time periods.

[0230] In one configuration, if an alarm is triggered, an alarm message may be presented to the user indicating that the flow rate setting should be reduced, and / or the power to the humidifier heater plate should be reduced, and / or the power to the heated breathing tube should be reduced. Alternatively, the controller may automatically reduce or control the flow rate and / or the power to the humidifier heater plate and / or the heated breathing tube to cool the device. The over-temperature alarm may be cleared or reset once the device has cooled sufficiently as sensed or measured by one or more temperature sensors.

[0231] In some configurations, the breathing apparatus may include one or more temperature sensors, such as a thermistor, in the blower module. The thermistor in the blower module monitors the blower temperature. In such configurations, if the sensed blower temperature exceeds a temperature threshold, the blower motor speed is reduced to a low speed or the blower motor is stopped for a period of time until the blower temperature has sufficiently decreased to an acceptable level based on the threshold. In this configuration, the blower thermistor is used as a safety feature to ensure that the blower motor speed is reduced, stopped or switched off to prevent damage to the blower if the actual blower temperature exceeds the threshold.

[0232] 8. General Furthermore, the embodiments may be implemented by hardware, software, firmware, middleware, microcode, or any combination thereof. When implemented in software, firmware, middleware, or microcode, the program code or code segments to perform the necessary tasks may be stored in a machine-readable medium, such as a storage medium or other storage. A processor may perform the necessary tasks. A code segment may represent a procedure, a function, a subprogram, a program, a routine, a subroutine, a module, a software package, a class, or any combination of instructions, data structures, program statements. A code segment may be coupled to another code segment or a hardware circuit by passing information, data, arguments, parameters, or memory contents. Information, arguments, parameters, data, etc. may be passed, forwarded, or transmitted via any suitable means including memory sharing, message passing, token passing, network transmission, etc.

[0233] In the foregoing, a storage medium may represent one or more devices for storing data, including read-only memory (ROM), random access memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, and / or other machine-readable media for storing information. The terms "machine-readable medium" and "computer-readable medium" include, but are not limited to, portable or non-removable storage devices, optical storage devices, and / or various other media that may store, store, or carry instructions and / or data, including non-transitory media.

[0234] The various illustrative logic blocks, modules, circuits, elements, and / or components described in connection with the examples disclosed herein may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic component, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, microcontroller, circuit, and / or state machine. A processor may also be implemented as a combination of computing components, e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in combination with a DSP core, or any other such configuration.

[0235] The methods or algorithms described in connection with the examples disclosed herein may be embodied directly in hardware, in software modules executable by a processor, or in a combination of both in the form of a processing unit, programming instructions, or other instructions, whether contained in a single device or distributed across multiple devices. The software modules may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art. The storage medium may be coupled to the processor such that the processor can read information from, and write information to, the storage medium. Alternatively, the storage medium may be integral to the processor.

[0236] One or more of the illustrated components and functions may be rearranged and / or combined into a single component or embodied in multiple components without departing from the invention. Also, additional elements or components may be added without departing from the invention. Furthermore, the features described herein may be implemented in software, firmware, hardware, and / or any combination thereof.

[0237] In its various aspects, the invention may be embodied in a computer-implemented process, a machine (such as an electronic device, or a general-purpose computer or other device that provides a platform on which a computer program may be executed), a process performed by such a machine, or an article of manufacture. Such articles may include computer program products or digital information products having stored thereon a computer-readable storage medium containing computer program instructions or computer readable data, as well as processes and machines for producing and using these articles of manufacture.

[0238] The foregoing description of the exemplary embodiments includes example configurations and configurations. Modifications may be made without departing from the scope of this disclosure and / or the appended claims.

Claims

1. 1. A respiratory assistance device configured to provide a flow of gas to a user for respiratory therapy, comprising: a flow generator operable to generate a flow of gas; a controller operatively connected to the flow generator and operable to control a motor speed of the flow generator to thereby control a flow rate of the gas flow; The controller: receiving an input representing a set flow rate at which the device will generate the flow of gas for a desired treatment session; predicting whether a steady state temperature of the device will exceed a high temperature threshold based at least in part on a motor speed required to generate the set flow rate; generating a predicted high temperature condition signal if the high temperature condition threshold is exceeded based on the prediction; The respiratory support device is configured to:

2. 2. The respiratory assistance device of claim 1, wherein predicting whether the steady state temperature will exceed the hot condition threshold is based on determining whether the required motor speed exceeds a maximum allowable motor speed, the maximum allowable motor speed representing a highest motor speed that the device can maintain for the set flow rate without the steady state temperature exceeding the hot condition threshold.

3. the maximum allowable motor speed is based on or a function of a predetermined thermal model; and optionally the thermal model represents the heat generated by the flow generator as a function of the flow rate and the motor speed; or 3. The respiratory assistance device of claim 2, wherein the thermal model represents heat generated by the flow generator and one or more non-flow generator heat sources, the heat generated by the flow generator being a function of the flow rate and the motor speed.

4. 4. The respiratory assistance device of claim 3, wherein the thermal model is configured to represent the one or more non-flow generator heat sources with respective preset values ​​that represent an estimate of a maximum amount of heat that may be generated by each of the one or more non-flow generator heat sources during operation.

5. predicting whether the steady state temperature will exceed the high temperature threshold; predicting the steady state temperature as a function of the required motor speed and set flow rate; and determining whether the predicted steady state temperature exceeds the high temperature threshold; Based on this, optionally, The respiratory assistance device of claim 1 , wherein predicting the steady state temperature includes determining an estimate from a predetermined thermal model.

6. The controller: determining whether the required motor speed exceeds a maximum allowable motor speed for the set flow rate; wherein the maximum allowable motor speed represents the high temperature threshold; and optionally, 2. The respiratory assistance device of claim 1, wherein the maximum allowable motor speed for the set flow rate is determined based on or is a function of a predetermined thermal model.

7. The controller: predicting the steady state temperature based on or as a function of a predetermined thermal model, the set flow rate, and the required motor speed; and determining whether the predicted steady state temperature exceeds the high temperature threshold; 2. The respiratory assistance device of claim 1, configured to predict whether the steady state temperature of the device will exceed the high condition threshold by:

8. 8. The respiratory assistance device of claim 7, wherein the thermal model generates a temperature variable representing the predicted steady state temperature based at least on the set flow rate, the required motor speed, and one or more other parameters representing non-flow generator heat sources of or associated with the device that contribute to the steady state temperature of the device.

9. the thermal model represents one or more heat sources of or associated with the apparatus, including at least representing heat generated by the flow generator as a function of motor speed and flow rate; and optionally 9. A respiratory assistance device according to any one of claims 3 to 8, wherein the thermal model further represents heat generated by one or more non-flow generator heat sources of or associated with the device that contribute to the steady state temperature of the device.

10. the controller is configured to receive a set flow rate input for a desired treatment session when the device is in a start-up or standby state with the flow generator stopped or idling at a non-therapeutic rate before a desired treatment session is initiated; and / or 10. A respiratory assistance device according to any one of claims 1 to 9, wherein the controller is configured to receive the set flow rate input while the device is already operating in a current treatment session at a first flow rate, the set flow rate input being a different second flow rate associated with a new desired treatment session.

11. The controller: estimating a first heat quantity representing heat contributed to the steady state temperature by one or more non-flow generator heat sources; estimating a maximum allowable motor speed of the flow generator corresponding to the second amount of heat representing heat contributed by the flow generator to the steady state temperature such that the sum of the first amount of heat and the second amount of heat does not cause the steady state temperature to exceed the high temperature threshold; determining the motor speed required for the set flow rate by increasing or varying the motor speed of the flow generator to the motor speed required for the flow generator to generate the set flow rate; and predicting that the steady-state temperature of the device will exceed the high temperature threshold if the determined required motor speed exceeds the estimated maximum allowable motor speed; 2. The respiratory assistance device of claim 1, configured to predict whether the steady state temperature of the device will exceed the high condition threshold based at least in part on a required motor speed by:

12. The controller: increasing or varying a motor speed of the flow generator to a motor speed required for the flow generator to produce the set flow rate, thereby determining the motor speed required for the set flow rate; estimating a first steady state temperature value representative of heat contributed to the steady state temperature by the flow generator; estimating a second steady state temperature value representative of heat contributed to said steady state temperature by one or more non-flow generator heat sources; predicting the steady state temperature of the device by summing the first steady state temperature value and the second steady state temperature value; and evaluating whether the predicted steady state temperature exceeds the high temperature threshold; 2. The respiratory assistance device of claim 1, configured to predict whether the steady state temperature of the device will exceed the high condition threshold based at least in part on a required motor speed by:

13. 13. The respiratory assistance device of claim 3, 4, 8, 9, 11, or 12, wherein the one or more non-flow generator heat sources include any one or more of the following non-flow generator components or variables of, connected to, or associated with the device: ambient temperature of the environment surrounding the device, a battery or power source, a heater plate of a humidifier, heater wires of a patient interface conduit, electronic circuits or components, a printed circuit board (PCB), a graphical user interface, and / or a display screen.

14. the steady state temperature is configurable to represent any predictable temperature of interest at, within or associated with the device; and / or the steady state temperature represents a sustained and / or stable temperature parameter, as opposed to a transient temperature parameter; and / or 14. A respiratory assistance device as claimed in any preceding claim, wherein the steady state temperature represents a predicted temperature parameter after the device has operated in a desired treatment session at the set flow rate for at least a predetermined minimum time such that the steady state temperature represents a sustained and / or stable temperature parameter.

15. the steady state temperature of the device represents a predicted temperature of the gas flow in the device at a particular region or location within the gas flow path of the device; and / or the steady state temperature of the device represents a predicted temperature within a particular location or area of ​​a main housing of the device; and / or the steady state temperature of the apparatus represents a predicted temperature at or within a region of a particular component or part of the respiratory assistance apparatus; and / or A respiratory assistance device according to any one of claims 1 to 14, wherein the steady state temperature of the device represents a predicted general overall temperature parameter associated with the device based on a thermal model of the device and / or one or more heat sources of interest of or associated with the device.

16. the high temperature threshold is a temperature parameter that is predetermined or selected based on the characteristics of the device and / or a particular type of expected steady state temperature; and optionally the steady state temperature represents a predicted temperature parameter related to the temperature of the gas flow at a particular area or location within the device, and the high temperature threshold represents a gas temperature safety threshold or value beyond which malfunction, damage to the device, and / or increased safety risk to users may occur; and / or 16. A respiratory assistance device as claimed in any one of claims 1 to 15, wherein the steady state temperature represents a predicted temperature parameter for a particular location or area of ​​a main housing of the device, and the high temperature threshold is configured to represent a housing temperature safety threshold or value beyond which malfunction, damage to the device and / or increased safety risk to a user may occur.

17. the controller is configured to issue an alarm when a predicted high temperature condition signal is generated; and optionally the alarm comprises one or more types of alarm: audible, visual, tactile, and / or haptic; and / or Respiratory assistance device according to any preceding claim, wherein the alarm comprises an alarm message or indication on a display screen or user interface of the device.

18. the controller is configured to overrule the set flow rate and disable the motor or slow the motor to an idle speed if the alarm is activated; or 18. The respiratory assistance device of claim 17, wherein the controller is configured to, if the alarm is issued, limit the motor speed to a maximum allowable motor speed and generate an alarm message or indication on a display screen or user interface of the device, the maximum allowable motor speed indicating a highest motor speed that the device can maintain for the set flow rate without the steady state temperature exceeding the high condition threshold.

19. 19. A respiratory assistance device as claimed in any one of claims 1 to 18, wherein the flow generator comprises one or more thermistors arranged within the flow generator housing or in thermal communication with the flow generator or the flow generator motor, the thermistors being configured to sense a temperature of the flow generator and / or the flow generator motor or to sense a temperature associated with the flow generator and / or the flow generator motor and generate a representative temperature signal.

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