Method for determining if a high flow therapy device is being used by a patient, a method for a remote processor thereof, a device for delivering high flow therapy to a patient, and a high flow therapy system - Patents.com

Abstract

A method is provided for use in a regulator or the like associated with a respiratory therapy device. A method for determining whether high-flow therapy is being used by a patient may include determining whether characteristics of airflow being delivered from a respiratory therapy device along an air circuit to an unsealed patient interface include significant variations in respiratory rate. The method may also include generating a notification of whether high-flow therapy is being used by the patient in response to the determination.

Description

[Technical field]

[0001] 1 CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of Australian Provisional Application No. 2015900907, filed March 13, 2015, the disclosure of which is incorporated herein by reference in its entirety.

[0002] 2 STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT Not applicable

[0003] 3. Name of organization for joint research and development Not applicable

[0004] 4. Sequence Listing Not applicable

[0005] [Field of the Invention] The present technology relates to one or more of the detection, diagnosis, treatment, prevention and amelioration of respiratory related disorders. The present technology also relates to medical devices or apparatus or uses thereof. [Background technology]

[0006] 5.2.1 The human respiratory system and its diseases The body's respiratory system facilitates gas exchange. The nose and oral cavity form the entrance to a patient's airways.

[0007] These airways contain a series of branching tubes that become narrower, shorter and more numerous the deeper they go into the lungs. The primary function of the lungs is gas exchange, allowing oxygen to enter the venous blood from the air and carbon dioxide to leave. The trachea divides into the right and left main bronchi, which further divide into the terminal bronchioles. The bronchi constitute the conducting airways and do not participate in gas exchange. The airways further divide into the respiratory bronchioles and finally into the alveoli. Gas exchange occurs in the alveolar region of the lungs, which is called the respiratory zone. See: "Respiratory Physiology", by John B. West, Lippincott Williams & Wilkins, 9th edition published 2011.

[0008] A range of respiratory disorders exists. Particular disorders may be characterized by particular manifestations such as apnea, hypopnea and hyperpnea.

[0009] Obstructive sleep apnea (OSA) is a form of sleep-disordered breathing (SDB) characterized by episodes such as closure or obstruction of the upper airway during sleep. It results from a combination of an abnormally small upper airway and normal loss of muscle tone in the tongue region, soft palate, and posterior oropharyngeal wall during sleep. The condition causes patients to pause in breathing, typically for 30-120 seconds, sometimes as many as 200-300 times per night. The result is excessive daytime sleepiness, which can lead to cardiovascular disease and brain damage. The condition is common, especially in middle-aged, overweight men, but patients are asymptomatic. See U.S. Pat. No. 4,944,310 (Sullivan).

[0010] Cheyne-Stokes respiration (CSR) is another form of sleep-disordered breathing. CSR is a disease of the patient's respiratory control that is followed by alternating periods of waxing and waning ventilation, known as the CSR cycle. CSR is characterized by repeated deoxygenation and reaeration of arterial blood. CSR can become harmful due to repeated hypoxia. Some patients experience repeated awakenings from sleep associated with CSR, leading to increased insomnia, increased sympathetic activity, and increased afterload. See U.S. Patent No. 6,532,959 (Berthon-Jones).

[0011] Chronic obstructive pulmonary disease (COPD) encompasses any of a group of lower airway diseases that share certain common characteristics, including increased resistance to air movement, increased expiratory phase of breathing, and loss of normal elasticity of the lungs. Examples of COPD include emphysema and chronic bronchitis. Causes of COPD include chronic smoking (primary risk factor), occupational exposure, air pollution, and genetic factors. Symptoms include dyspnea on exertion, chronic cough, and sputum production.

[0012] A range of treatments are available to treat or ameliorate such conditions, and otherwise healthy individuals may also benefit from preventative treatments for respiratory disease, but these suffer from a number of deficiencies.

[0013] 5.2.2 Respiratory treatment Respiratory pressure therapy (e.g., nasal continuous positive airway pressure (CPAP) therapy) is used in the treatment of obstructive sleep apnea (OSA). Its mechanism of action is that nasal continuous positive airway pressure acts as a pneumatic splint, for example by pushing the soft palate and tongue forward or backward against the posterior oropharyngeal wall, thereby preventing the upper airway from closing.

[0014] In comparison to respiratory pressure therapy, high-flow therapy (HFT) may rely not on positive airway pressure delivered to a sealed patient interface, but rather on delivery of air at a therapeutic flow rate to adjacent the entrance(s) to the patient's airway via an unsealed patient interface that is open to the atmosphere. High-flow therapy is used in the treatment of OSA, CSR, and COPD. The hypothesized mechanism of action is that air delivered to the airway at a high flow rate bleeds out of the patient's anatomical dead space, increasing the amount of rebreathed CO2. 2 This reduces the amount of erythrocyte secretion, thereby increasing the efficiency of gas exchange.

[0015] The range of high flow rates delivered is about 0 to 120 liters / minute, preferably about 0 to 75 liters / minute, and more preferably about 0 to about 50 liters / minute to provide comfort and effectiveness and reduce rebreathing, with a preferred range of about 10 to about 35 liters / minute.

[0016] The delivery air temperature may range from about 0°C to about 50°C, more preferably from about +4°C to about +45°C, even more preferably at room temperature up to 40°C, with the most preferred range being 30°C to 37°C for comfort and efficacy.

[0017] The delivered relative humidity of the air may be up to 100% room humidity (e.g., in the range of about 50% to about 100%, or in the range of about 70% to about 100%, or in the range of about 80% to about 95%), with a preferred range of 80% to 90% for comfort and efficacy. The absolute humidity range may be from about 0 to about 82 mg / L, or more preferably from about 27 to about 44 mg / L.

[0018] High flow therapy is described in U.S. Patent Application Publication No. 2011-0253136, filed as International Patent Application PCT / AU09 / 00671 on May 28, 2009, which is incorporated by reference in its entirety. High flow therapy may be used in conjunction with respiratory pressure therapy.

[0019] 5.2.3 Treatment system Respiratory therapy may be provided by a therapy system or apparatus, which may include a respiratory therapy device (RT device), an air circuit, a humidifier, a patient interface, and data management.

[0020] 5.2.3.1 Patient interface The patient interface may be used to provide a wearer with an interface to a respiratory appliance, for example by providing airflow to an airway inlet. The airflow may be provided via a mask to the nose and / or mouth, a tube to the mouth, or a tracheotomy tube to the patient's trachea. Depending on the therapy being applied, the patient interface may form a seal with, for example, an area of ​​the patient's face, thereby providing a pressure at which there is sufficient dispersion with atmospheric pressure for therapy to be performed (e.g., approximately 10 cmH above atmospheric pressure). 2 The patient interface may also have one or more vents to provide gas exhaust to atmosphere. In other forms of therapy (e.g., high-flow therapy), the patient interface may not be sealed (i.e., may not form a seal with the airway inlet). Airflow may be provided via a cannula to the nose, a tube to the oral cavity, or a tracheotomy tube to the patient's trachea. When such non-sealed patient interfaces are used in conjunction with high-flow therapy, atmosphere escapes through gaps between the interface and the patient's nares, essentially allowing significant therapeutic airflow. Under such escape conditions, the lack of a pressure-controlled environment (e.g., between the patient and the cannula interface) may be somewhat disruptive to the use of the patient's therapy and / or sensing or detection conditions related to the patient's breathing. Thus, embodiments of the present technology may be implemented to eliminate the difficulty of obtaining metrology for such therapy while using conventional sensors.

[0021] 5.2.3.2 Respiratory Therapy (RT) Devices Air pressure generators are known for a range of applications (industrial-scale ventilation systems). However, air pressure generators for medical applications have specific requirements that cannot be met by more common air pressure generators (e.g., reliability, size and weight requirements of medical devices). In addition, even devices designed for medical applications may have shortcomings in one or more of the following: comfort, noise, ease of use, effectiveness, size, weight, manufacturability, cost and reliability.

[0022] One known RT device used to treat sleep-disordered breathing is the S9 Sleep Therapy System manufactured by ResMed Limited. Another example of an RT device is a ventilator. Ventilators, such as the ResMed Stellar® series of adult and pediatric ventilators, can provide invasive and non-invasive independent ventilation support for a range of patients for the treatment of multiple conditions, including but not limited to CSR and COPD.

[0023] The RT device typically includes a pressure generator (e.g., a motor-driven blower or compressed gas reservoir) and is configured to deliver a flow of air to the patient airway. The outlet of the RT device is connected via an air circuit to a patient interface as described above.

[0024] 5.2.3.3 Humidifier Delivery of the air flow without humidification can cause drying of the airway. The use of a humidifier in conjunction with the RT device and patient interface produces humidified gas, minimizing drying of the nasal and / or throat mucosa and increasing comfort of the patient airway. Additionally, in cooler weather, the application of warm air to the face at and around the patient interface is often more comfortable than cool air. A range of artificial humidification devices and systems are known, but do not meet the specialized demands of medical humidification.

[0025] 5.2.3.4 Data Management There may be clinical reasons for obtaining data to determine whether a patient prescribed respiratory therapy is "compliant" (e.g., whether the patient is using their RT device in accordance with certain "compliance rules" associated with the prescribed respiratory therapy). An example of a compliance rule for CPAP therapy requires that the patient use the RT device for at least 4 hours per night for at least 21-30 consecutive days to be considered compliant. Similar compliance rules may be implemented for high-flow therapy. To determine patient compliance, a provider of the RT device (e.g., a health care provider) may manually obtain therapy data describing the patient's respiratory therapy using the RT device, extrapolate / calculate usage over a period of time, and compare it to the compliance rules. After the health care provider determines that the patient has used the RT device in accordance with the compliance rules, the health care provider may notify a third party (e.g., an insurance provider) that the patient is compliant. There may be other aspects of the patient's therapy that benefit from communication of therapy data to a third party or external system.

[0026] Conventional methods exist for analyzing therapy data to determine when a patient is using their RT device to deliver CPAP therapy or other respiratory pressure therapy. However, due to the different air pressures of high-flow therapy due to its usually unsealed character, such methods produce inaccurate results when used to determine whether the RT device is being used to deliver high-flow therapy. Therefore, there is a need for a method and apparatus for determining when an RT device is being or has been used for high-flow therapy. Summary of the Invention

[0027] 6. Brief summary of the technology The present technology relates to the provision of medical devices for use in the diagnosis, amelioration, treatment or prevention of respiratory disorders, which medical devices have one or more of improved comfort, cost, effectiveness, ease of use and manufacturability.

[0028] Generally, the present technology relates to devices and methods used in the diagnosis, amelioration, treatment or prevention of respiratory disorders.

[0029] One form of the present technology includes devices and methods for determining whether a patient is using or has used high-flow therapy based on flow and / or pressure signals. These devices and methods may look for significant variations in the band of respiratory rates per unit time in one or more of these signals to determine whether a patient is using high-flow therapy.

[0030] According to one aspect of the present technology, a method for determining whether high flow therapy is being used by a patient is provided. The method may include determining, by evaluation of the one or more signals in a controller associated with a respiratory therapy device, one or more signals from one or more sensors and determining whether a characteristic of the flow of air being delivered from the respiratory therapy device along the air circuit to a non-sealed patient interface includes significant variation within a band of breath rates per unit time. The method may also include generating an output indication in the controller based on the determining whether high flow therapy is being used by the patient.

[0031] According to another aspect of the present technology, there is provided an apparatus for delivering high flow therapy to a patient. The apparatus may include a servo-controlled blower configured to generate an airflow along an air circuit to an unsealed patient interface at a predetermined therapeutic flow rate. The apparatus may include one or more transducers configured to generate respective signals of respective characteristics of the airflow being generated. The apparatus may include a central controller configured to control the servo-controlled blower. The apparatus may include a processor. The processor may be configured to receive the one or more signals. The processor may be configured to control a determination of whether the characteristic of the airflow indicated by one of the one or more signals includes significant variation within a band of respiratory rates per unit time. The processor may be configured to generate an indication of whether high flow therapy is being used by the patient in response to the determination.

[0032] In accordance with another aspect of the present technology, there is provided an apparatus for delivering high flow therapy to a patient. The apparatus may include flow means for generating an air flow along an air circuit to an unsealed patient interface. The apparatus may include means for controlling the flow means. The apparatus may include means for generating one or more signals indicative of respective characteristics of the air flows being generated. The apparatus may include means for receiving the one or more signals. The apparatus may include means for determining whether the characteristic of the air flow indicated by one of the one or more signals includes significant variation within a band of respiratory rates per unit time. The apparatus may include means for generating an indication of whether high flow therapy is being used by the patient in response to the determination.

[0033] According to another aspect of the present technology, a high flow therapy system is provided. The high flow therapy system may include a non-sealed patient interface. The system may include an air circuit configured to connect to the non-sealed patient interface. The system may include a servo-controlled blower configured to generate an air flow along the air circuit. The system may include a central controller configured to control the servo-controlled blower. The system may include one or more transducers configured to generate one or more signals indicative of respective characteristics of the air flows being generated. The system may include a processor. The processor may be configured to receive the one or more signals. The processor may be configured to control a determination as to whether the characteristic of the air flow indicated by one of the one or more signals includes significant variation within a band of breath rates per unit time. The processor may be configured to generate an indication of whether high flow therapy is being used by the patient in response to the determination.

[0034] Of course, some of the above aspects may form sub-aspects of the present technology, and various ones of the sub-aspects and / or aspects may be combined in various ways to form further aspects or sub-aspects of the present technology.

[0035] Other features of the present technology will become apparent in light of the information contained in the following detailed description, drawings, and claims.

[0036] The present technology is illustrated by way of example and not by way of limitation in the accompanying drawings in which like reference numbers include similar elements as follows: [Brief description of the drawings]

[0037] [Figure 1]7.1 Treatment System Figure 1 shows a system including a patient 1000 wearing a patient interface 3000. The patient interface 3000 takes the form of nasal pillows and receives air at positive pressure from a RT device 4000. Air from the RT device is humidified in a humidifier 5000 and travels along an air circuit 4170 to the patient 1000. A sleep companion 1100 is also shown. [Diagram 2] [7.2 Respiratory System and Facial Anatomy] Figure 2 shows an overview of the human respiratory system, including the nose and oral cavity, larynx, vocal folds, esophagus, trachea, bronchi, lungs, alveolar sacs, heart and diaphragm. [Figure 3a] 7.3 Patient Interface FIG. 3a shows a sealed patient interface 3000 suitable for respiratory pressure therapy. [Figure 3b] 3b shows a non-sealed patient interface 3800 that is suitable for high flow therapy and is used on the patient 1000. [Figure 4a] 7.4 Respiratory Therapy Device FIG. 4a shows a RT device 4000 in accordance with one form of the present technology. [Figure 4b] 4b is a schematic diagram of the pneumatic pathway of a RT device in accordance with one form of the present technology, with upstream and downstream directions shown. [Figure 4c] FIG. 4c is a schematic diagram of electrical components of an RT device in accordance with one form of the present technology. [Figure 5a] 7.5 Humidifier FIG. 5a shows an isometric view of a humidifier 5000. [Figure 5b] FIG. 5b is an isometric view of the humidifier showing the humidifier reservoir 5110 removed from the humidifier reservoir dock 5130. [Figure 6a] 7.6 Therapy Usage Determination FIG. 6a is a schematic diagram of an electrical circuit that forms a simple model of an RT device that delivers high-flow therapy to a breathing patient through an unsealed patient interface. [Figure 6b]FIG. 6b is a schematic diagram of an electrical circuit that forms a more sophisticated model of an RT device that delivers high-flow therapy to a breathing patient. [Figure 6c] FIG. 6c is a schematic diagram of the electrical circuitry forming a two-nostril model of an RT device for delivering high-flow therapy to a breathing patient. [Figure 7a] FIG. 7a is a flow chart illustrating a method for determining if a patient is using high-flow therapy in accordance with one form of the present technology. [Figure 7b] FIG. 7b is a flowchart illustrating a method of monitoring high flow therapy for a patient in accordance with one form of the present technology. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] Before describing the present technology in more detail, it should be understood that the present technology is not limited to the specific examples described herein, which may vary. It should also be understood that the terms used in the present disclosure are for the purpose of describing the specific examples described herein, and are not limiting.

[0039] The following description is provided in conjunction with various examples that may share one or more common characteristics and / or features. It should be understood that one or more features of any one example may be combined with one or more features of another example or the other examples. In addition, any single feature or combination of features in any of these examples may constitute an additional example.

[0040] 8.1 Therapy In one form, the present technology includes a method of treating a respiratory disorder comprising delivering a flow of air at a high flow rate adjacent the entrance to the airways of a patient 1000.

[0041] In a particular example of the present technology, a flow of air is delivered at a high flow rate to the patient's nasal passages via one or both nostrils.

[0042] 8.2 Treatment Systems In one form, the present technology includes an apparatus or device for the treatment of respiratory disorders. The apparatus or device may include a RT device 4000 that delivers air to a patient 1000 at a high flow rate to a non-sealed patient interface 3800 via an air circuit 4170.

[0043] 8.3 Patient Interface A non-invasive sealed patient interface 3000 in accordance with one aspect of the present technology includes the following functional aspects: a seal forming structure 3100, a cavity chamber 3200, a positioning and stabilizing structure 3300, an air vent 3400, a form of connection port 3600 for connection to an air circuit 4170, and a forehead support 3700. In use, the seal forming structure 3100 is positioned to surround an entrance to the patient's airways to facilitate the delivery of air at positive pressure to the airways.

[0044] The non-sealed patient interface 3800 takes the form of a nasal cannula and includes nasal prongs 3810a and 3810b. The nasal prongs 3810a and 3810b can deliver air to each nostril of the patient 1000. Such nasal prongs often do not form a seal with the skin surface inside or outside the nostril. Air to the nasal prongs can be delivered by one or more air supply lumens 3820a and 3820b connected by a nasal cannula configuration to the non-sealed patient interface 3800. The lumens 3820a and 3820b extend from the non-sealed patient interface 3800 in the nasal cannula configuration to a RT device that generates a high flow rate of air flow.

[0045] Another example of a non-sealed patient interface 3800 is a transtracheal interface.

[0046] 8.4 Respiratory Therapy Devices The RT device 4000 according to an aspect of the present technology includes mechanical and pneumatic components 4100, electrical components 4200, and is configured to execute one or more algorithms 4300. The RT device may have an external housing 4010. The external housing 4010 is formed in two parts, an upper section 4012 and a lower section 4014. Further, the external housing 4010 may include one or more panel(s) 4015. The RT device 4000 includes a chassis 4016 that supports one or more internal components of the RT device 4000. The RT device 4000 may include a handle 4018.

[0047] The air pressure path of the RT device 4000 may include one or more air path items (e.g., an inlet air filter 4112), an inlet muffler 4122, a pressure generator 4140 capable of delivering air at high flow rates (e.g., a blower 4142), an outlet muffler 4124 and one or more transducers 4270 (e.g., a pressure sensor 4272 and a flow sensor 4274).

[0048] One or more of the pneumatic path items may be disposed within a moveable integral structure referred to as a pneumatic block 4020. The pneumatic block 4020 may be disposed within the outer housing 4010. In one form, the pneumatic block 4020 is supported by or formed as part of the chassis 4016.

[0049] The RT device 4000 may have a power supply 4210, one or more input devices 4220, a central controller 4230, a therapy device controller 4240, a pressure generator 4140, one or more protection circuits 4250, a memory 4260, a transducer 4270, a data communication interface 4280, and one or more output devices 4290. The electrical components 4200 may be mounted on a single printed circuit board assembly (PCBA) 4202. In another form, the RT device 4000 may include more than one PCBA 4202.

[0050] 8.4.1 RT Device Mechanical & Pneumatic Components An RT device may include one or more of the following components as an integral unit: In the alternative, one or more of the following components may be disposed as separate units.

[0051] 8.4.1.1 Air filter(s) An RT device in accordance with one form of the present technology may include an air filter 4110 or multiple air filters 4110.

[0052] In one form, the inlet air filter 4112 is positioned at the beginning of the air pressure path upstream of the pressure generator 4140 .

[0053] In one form, an outlet air filter 4114, such as an antibacterial filter, is positioned between the outlet of the pneumatic block 4020 and the patient interface.

[0054] 8.4.1.2 Muffler(s) In one form of the present technology, an inlet muffler 4122 is placed in the pneumatic path upstream of a pressure generator 4140 .

[0055] In one form of the present technology, the outlet muffler 4124 is placed in the pneumatic path between the pressure generator 4140 and the patient interface.

[0056] 8.4.1.3 Pressure generator In one form of the present technology, the pressure generator 4140 that generates the airflow at a high flow rate is a servo-controlled blower 4142. For example, the blower 4142 may include a brushless DC motor 4144 with one or more impellers housed in a volute. The blower 4142 may be servo-controlled to deliver the airflow at a therapeutic flow rate Qth. In such an implementation, the total flow rate Qt of the airflow is monitored by the flow transducer and the speed of the blower 4142 as follows, whereby the pressure Pd of the airflow at the output of the blower 4142 is adjusted to maintain the total flow rate Qt at or near the therapeutic flow rate Qth. The therapeutic flow rate Qth may be as high as about 120 liters / min, but more typically in the range of 20-30 liters / min.

[0057] The blower 4142 may be described in any one of the following patents or patent applications, the entireties of which are incorporated by reference herein: U.S. Patent No. 7,866,944, U.S. Patent No. 8,638,014, U.S. Patent No. 8,636,479; and PCT Patent Application Publication No. WO2013 / 020167.

[0058] The pressure generator 4140 is under the control of the therapy device controller 4240 .

[0059] In other forms, pressure generator 4140 can be a piston-driven pump, a pressure regulator connected to a high pressure source (eg, a compressed air reservoir), or a bellows.

[0060] 8.4.1.4 Transducer(s) The transducer 4270 may be internal to the RT device or external to the RT device. An external transducer may be located on the air circuit or form part of it (e.g., the patient interface). An external transducer may take the form of a non-contact sensor (e.g., a Doppler radar motion sensor with data transmission or forwarding to the device).

[0061] In one form of the present technology, one or more transducers 4270 are positioned upstream and / or downstream of the pressure generator 4140. The one or more transducers 4270 may be constructed and arranged to measure a property (e.g., flow rate, pressure, absolute or relative humidity, or temperature at a point in the pneumatic path). The transducers 4270 generate signals indicative of those properties and transmit those signals to the central controller 4230.

[0062] In one form of the present technology, one or more transducers 4270 may be placed near the patient interface. In another form of the present technology, one or more transducers 4270 may be placed near the air outlet of the RT device 4000. External transducers may be used to measure ambient conditions (e.g., ambient pressure, temperature, or relative or absolute humidity).

[0063] In one form, the signal from the transducer 4270 may be filtered (eg, by low-pass, high-pass or band-pass filtering).

[0064] 8.4.1.4.1 Flow Transducers The flow transducer 4274 according to the present technology may be based on a differential pressure transducer (eg, an SDP600 series differential pressure transducer from SENSIRION).

[0065] In one form, the flow transducer 4274 generates a signal indicative of the total flow rate, Qt, of the airflow being delivered from the RT device 4000 .

[0066] 8.4.1.4.2 Pressure transducers A pressure transducer 4272 according to the present technology is placed in fluid communication with the pneumatic path. One example of a suitable pressure transducer is a sensor from the HONEYWELL ASDX series. Another suitable pressure transducer is a sensor from the NPA series from GENERAL ELECTRIC.

[0067] In one form, the pressure transducer 4272 generates a signal indicative of the pressure Pd of the airflow at the outlet of the RT device 4000 .

[0068] 8.4.1.4.3 Motor Speed ​​Transducers In one form of the present technology, the motor speed transducer 4276 can be used to determine the rotational speed of the motor 4144 and / or the blower 4142. A motor speed signal from the motor speed transducer 4276 can be provided to the therapy device controller 4240. The motor speed transducer 4276 can be a speed sensor, such as, for example, a Hall effect sensor.

[0069] 8.4.1.4.4 Other transducers One or more humidity / temperature sensors, such as the Sensirion SHT75, may be used to determine the humidity and temperature of the treatment air stream as well as the ambient humidity and temperature.

[0070] The one or more electrical sensors may be configured to sense the current consumed by the motor 4144 or the humidifier 5000 or its respective power supply unit. The sensed current may be used to determine the instantaneous or average power consumed by the treatment system or its components.

[0071] 8.4.1.5 Spill-back prevention valves In one form of the present technology, an anti-spillback valve is located between the humidifier 5000 and the pneumatic block 4020. The anti-spillback valve is constructed and positioned to reduce the risk of water flowing upstream of the humidifier 5000, for example to the motor 4144.

[0072] 8.4.1.6 Air circuits An air circuit 4170 in accordance with aspects of the present technology is a conduit or tube constructed and arranged in use to allow the transfer of air flow between two components (eg, the pneumatic block 4020 and the patient interface).

[0073] In particular, the air circuit 4170 may be fluidly connected to the outlet of the pneumatic block and the patient interface. This air circuit may be referred to as the air delivery tube. In some cases, there may be separate prongs of the circuit for inhalation and exhalation. In other cases, a single prong is used.

[0074] In some forms, the air circuit 4170 may include one or more heating elements configured to heat the air in the air circuit (e.g., maintain or increase the air temperature). The heating elements may take the form of a heated wire circuit and may include one or more transducers (e.g., temperature sensors). In one form, the heated wire circuit may be spirally wound around the axis of the air circuit 4170. The heating elements may be in communication with a controller (e.g., the central controller 4230 or the humidifier controller 5250). One example of an air circuit 4170 including a heated wire circuit is described in U.S. Patent Application Publication No. US / 2011 / 0023874, which is incorporated by reference in its entirety.

[0075] 8.4.1.7 Oxygen Delivery In one form of the present technology, supplemental oxygen 4180 is delivered to one or more points in the pneumatic pathway (eg, upstream of the pneumatic block 4020), the pneumatic circuit 4170, and / or the patient interface.

[0076] 8.4.2 RT Device Electrical Components 8.4.2.1 Power supply The power supply 4210 can be located inside or outside the external housing 4010 of the RT device 4000.

[0077] In one form of the present technology, the power supply 4210 provides power only to the RT device 4000. In another form of the present technology, the power supply 4210 provides power to both the RT device 4000 and the humidifier 5000.

[0078] 8.4.2.2 Input Devices In one form of the present technology, the RT device 4000 includes one or more input devices 4220 in the form of buttons, switches, or dials to allow human interaction with the device. The buttons, switches, or dials may be physical devices or software devices accessible via a touch screen. The buttons, switches, or dials may be physically connected to the external housing 4010 in one form, or may communicate wirelessly with a receiver electrically connected to the central controller 4230 in another form.

[0079] In one form, the input device 4220 may be constructed and arranged to allow a person to select values ​​and / or menu options.

[0080] 8.4.2.3 Central Controller In one form of the present technology, the central controller 4230 is one or more processors suitable for controlling the RT device 4000 .

[0081] Suitable processors may include x86 INTEL processors, such as processors based on the ARM® Cortex®-M processor from ARM Holdings (e.g., the STM32 series microcontrollers from ST MICROELECTRONIC). In certain alternative forms of the present technology, 32-bit RISC CPUs (e.g., 16-bit RISC CPUs such as the STR9 series microcontrollers from ST MICROELECTRONICS or processors from the MSP430 family of microcontrollers manufactured by TEXAS INSTRUMENTS) may also be suitable.

[0082] In one form of the present technology, the central controller 4230 is a dedicated electronic circuit.

[0083] In one form, the central controller 4230 is an application specific integrated circuit. In another form, the central controller 4230 is a discrete electronic component.

[0084] The central controller 4230 may be configured to receive input signal(s) from one or more transducers 4270 and one or more input devices 4220.

[0085] The central controller 4230 may be configured to provide output signal(s) to one or more of the output device 4290, the therapy device controller 4240, the data communication interface 4280, and the humidifier controller 5250.

[0086] In some forms of the present technology, the central controller 4230 is configured to execute one or more methods described herein (e.g., one or more algorithms 4300 expressed as a computer program stored in a non-transitory computer-readable storage medium (e.g., memory 4260)). In some forms of the present technology, the central controller 4230 may be integrated with the RT device 4000. However, in some forms of the present technology, some methods may be performed by a remotely located device. For example, the remotely located device may determine ventilator control settings or detect a respiratory-related episode by analysis of stored data (e.g., from any of the sensors described herein).

[0087] 8.4.2.4 Clock The RT device 4000 may include a clock 4232 connected to the central controller 4230 .

[0088] 8.4.2.5 Therapy Device Controller In one form of the present technology, the therapy device controller 4240 is a control module 4330 that forms part of the algorithm 4300 executed by the central controller 4230.

[0089] In one form of the present technology, the therapy device controller 4240 is a dedicated motor control integrated circuit. For example, in one form, the MC33035 brushless DC motor controller manufactured by ONSEMI is used.

[0090] 8.4.2.6 Protection circuit The one or more protection circuits 4250 in accordance with the present technology may include electrical protection circuits, temperature and / or pressure safety circuits.

[0091] 8.4.2.7 Memory In accordance with one aspect of the present technology, the RT device 4000 includes memory 4260 (e.g., non-volatile memory). In some forms, the memory 4260 may include battery-powered static RAM. In some forms, the memory 4260 may include volatile RAM.

[0092] The memory 4260 may be located on the PCBA 4202. The memory 4260 may take the form of an EEPROM or a NAND flash.

[0093] Additionally or alternatively, the RT device 4000 includes memory 4260 in a removable form (eg, a memory card made according to the Secure Digital (SD) standard).

[0094] In one form of the present technology, the memory 4260 functions as a non-transitory computer-readable storage medium having stored thereon computer program instructions that represent one or more of the methods (e.g., one or more algorithms 4300) described herein.

[0095] 8.4.2.8 Data communication systems In one form of the present technology, a data communications interface 4280 is provided and connected to a central controller 4230. The data communications interface 4280 may be connectable to a remote external communications network 4282 and / or a local external communications network 4284. The remote external communications network 4282 may be connectable to a remote external device 4286. The local external communications network 4284 may be connectable to a local external device 4288.

[0096] In one form, the data communications interface 4280 is part of the central controller 4230. In another form, the data communications interface 4280 is separate from the central controller 4230 and may include an integrated circuit or processor.

[0097] In one form, the remote external communications network 4282 is the Internet. The data communications interface 4280 may use wired communications (e.g., via Ethernet or fiber optics) or may use wireless protocols (e.g., CDMA, GSM, LTE) to connect to the Internet.

[0098] In one form, the local external communications network 4284 uses one or more communications standards (eg, Bluetooth® or consumer infrared protocol, or power line communications).

[0099] In one form, the remote external device 4286 is one or more computers (e.g., a cluster of networked computers). In one form, the remote external device 4286 may be a virtual computer rather than a physical computer. In either case, such a remote external device 4286 may be accessible to appropriately authorized personnel, such as a clinician.

[0100] The local external device 4288 may be a personal computer, a cell phone, a tablet or a remote control.

[0101] 8.4.2.9 Output Devices Output devices 4290 according to the present technology may take the form of one or more of visual, audio and tactile units. The visual display may be a Liquid Crystal Display (LCD) or a Light Emitting Diode (LED) display.

[0102] 8.4.2.9.1 Display Drivers The display driver 4292 receives as input characters, symbols or images to be displayed on the display 4294 and converts them into commands that cause the display 4294 to display those characters, symbols or images.

[0103] 8.4.2.9.2 Display The display 4294 is configured to visually display characters, symbols, or images in response to commands received from the display driver 4292. For example, the display 4294 may be an eight-segment display, in which case the display driver 4292 converts each character or symbol (e.g., the number "0") into eight logic signals indicating which of the eight respective segments to activate to display the particular character or symbol.

[0104] 8.4.2.9.3 Warning The output device 4290 may take the form of an alert generator. The alert may take the form of a visual indicator (e.g., a flashing light) or an audio signal (e.g., a beep).

[0105] 8.4.3 RT Device Algorithms 8.4.3.1 Determining the Use of High-Flow Therapy The present technology provides improvement(s) in the art of respiratory therapy, particularly with respiratory therapy devices. For example, the present technology may enable a device to automatically determine conditions associated with a patient's use of high-flow therapy when an unsealed patient interface is used. Such determination(s) may be made in a processor, thus providing improvement(s) in controller or processor functionality. For example, in one form of the present technology, an algorithm for determining high-flow therapy usage receives as inputs a signal indicative of the pressure at the RT device outlet, Pd, and a signal indicative of the total flow rate, Qt, of air being delivered from the RT device 4000. The algorithm for determining high-flow therapy usage generates as output a time series of Boolean usage indications of whether high-flow therapy is being used by the patient 1000 at successive times.

[0106] In one form of the present technology, a central controller 4230 of the RT device 4000 can execute an algorithm that determines the usage of high flow therapy.

[0107] In other forms of the present technology, the algorithm for determining the use of high flow therapy may be executed by a processor of a remote external computing device 4286 configured to communicate with the RT device 4000 via a remote external communications network 4282. In such forms, the RT device 4000 may transmit signals indicative of the device pressure Pd and the total flow Qt to the remote external computing device 4286 via the remote external communications network 4282. The remote external computing device 4286 then executes the algorithm for determining the use of high flow therapy.

[0108] In yet other forms, the algorithms for determining high flow therapy usage may be executed by the central controller 4230 of the RT device 4000 and partially executed by the processor of the remote external computing device 4286. For example, the central controller 4230 may process device pressure and total flow signals to generate intermediate outputs and output these intermediate outputs to the processor of the remote external computing device 4286, which then are processed to generate a time-series usage indication.

[0109] In either case, the algorithm for determining high-flow therapy usage may be performed in "real-time" or as a post-process (i.e., on stored data indicating device pressure Pd and total flow Qt after a therapy session is completed). For post-processing runs, the device pressure and flow data may be stored on the memory 4260 of the RT device 4000 and / or on the memory of the remote external computing device 4286 as a time series of samples at a predefined sampling rate.

[0110] The device pressure and total flow signals are generated by appropriately positioned pressure transducer 4272 and flow transducer 4274, respectively. In another form of the present technology, an algorithm for determining use of high flow therapy receives as an input a signal indicative of the pressure in the patient interface Pm. The patient interface pressure Pm may be generated directly by an appropriately positioned pressure transducer 4272, or may be formed from the device pressure Pd by a pressure compensation algorithm that also takes the total flow Qt as an input. The pressure compensation algorithm estimates the pressure drop through the air circuit 4170 using the total flow Qt and subtracts the estimated pressure drop from the device pressure Pd to calculate the patient interface pressure Pm.

[0111] The RT device 4000 may accumulate usage indications generated by an algorithm that determines usage of the high-flow therapy into a record of the patient's 1000 usage of the high-flow therapy over time. The RT device 4000 may take different actions based on such usage record. One example of such an action is to generate a compliance report summarizing the patient's 1000 usage of the high-flow therapy over a given interval. Such a report may be forwarded via a remote external communications network 4282 to a remote external computing device 4286 associated with, for example, a healthcare provider.

[0112] In another example, the therapy control module 4330 of the RT device 4000 may adjust one or more parameters of the high-flow therapy (e.g., therapy flow rate Qth) in response to a record of usage of the high-flow therapy. For example, if the usage record indicates that usage over time is declining, the therapy flow rate Qth may be decreased to encourage use of the high-flow therapy. Thus, in some cases, usage indications or accumulated records may be evaluated in the controller to act as a trigger for a change in the operation of the controller of the RT device 4000. As a further example, the controller may discontinue therapy (e.g., reduce or stop flow generation, for example by changing the control operation of the blower motor) when sufficient usage indications are met (e.g., when a certain time threshold is met) or when usage indications indicate that the device is not being used at all.

[0113] The RT device 4000 may generate an alert (through the output device 4290) based on the usage indications or its accumulated records. For example, if the accumulated records indicate that the patient 1000 has discontinued use of high-flow therapy for more than a predetermined interval, the RT device 4000 may generate an alert. Such an alert may be, for example, an output of the RT device 4000 (e.g., activation of an audio generator or speaker of the RT device 4000 or other audio generator or speaker of a device in communication with the RT device 4000, or activation of an output alert light on the display 4294 of the RT device 4000, or other display of a local or remote external device 4288 or 4286 in communication with the RT device 4000).

[0114] 6a is a circuit diagram of the electrical circuit model 6000. The electrical circuit model 6000 is a simple model of a RT device 4000 that delivers high flow therapy to a breathing patient 1000 through a non-sealed patient interface (e.g., non-sealed patient interface 3800). In the electrical circuit model 6000, voltage models pressure and current models flow. The RT device 4000 is modeled by a controlled voltage source 6010. The air circuit 4170 is modeled by a resistance 6030. The total flow Qt is modeled by the current in the air circuit resistance 6030, and the device pressure Pd is modeled by the voltage at the output of the voltage source 6010. The pressure Pm in the non-sealed patient interface 3800 is modeled by the voltage at the end of the air circuit resistance 6030. If the air circuit 4170 is occluded, the air circuit resistance 6030 becomes infinite (i.e., an open circuit). The resistance between the inside of the unsealed patient interface 3800 and the inside of the patient's nose is modeled by an interface resistance 6050. The pressure in the patient's nose, Pnose, is modeled by the voltage at the ends of the interface resistance 6050.

[0115] The respiratory system of patient 1000 is modeled by an airway resistance 6025 in series with a capacitance 6035 and an AC voltage source 6020. Capacitance 6035 models the air pressure compliance of the patient's lungs. AC voltage source 6020 models the breathing of patient 1000 by oscillating between a small negative voltage during the inspiration portion of the breathing cycle and a small positive voltage during the expiration portion of the breathing cycle.

[0116] 6b is a circuit diagram of an electrical circuit model 6100. The electrical circuit model 6100 is a more advanced model of the RT device 4000 that delivers high flow therapy to a breathing patient 1000 through an unsealed patient interface 3800 rather than the electrical circuit model 6000 of FIG. 6a. The electrical circuit model 6100 includes elements 6110, 6120, 6125, 6130, 6135, and 6150. These elements are the same as their respective counterparts 6010, 6020, 6025, 6030, 6035, and 6050 in the electrical circuit model 6000. The circuit model 6100 also includes an additional "leakage resistor" 6140 to ground in parallel with the model 6025 / 6010 of the patient 1000. The leak resistance 6140 models a leak path from inside the patient's nose to atmosphere due to a gap between the unsealed patient interface 3800 and the inlet(s) to the patient's 1000 airway(s) that interface with the unsealed patient interface 3800. Because the leak resistance 6140 is lower than the patient airway resistance 6125, the total flow Qt is significantly different from the patient respiratory flow Qr, which is modeled as a current in the airway resistance 6125. This is in contrast to more conventional sealed or pressurized systems used to deliver respiratory pressure therapy, where instead of a leak resistance 6140, a much higher impedance was used that modeled the flow of air through the vent 3400 to atmosphere with the interface properly positioned on the patient's face. In such a system, the significant drop in impedance to atmosphere creates a large difference in static pressure in the system between when the patient is using respiratory pressure therapy and when the interface is disconnected from the patient. Therefore, it is straightforward to detect when the patient is using respiratory pressure therapy from the static pressure.

[0117] The leak resistance 6140 depends on the position of the unsealed patient interface 3800 relative to the airway inlet(s). Since this cannot be predicted with a high degree of accuracy, the leak resistance 6140 is modeled as a variable. If the unsealed patient interface 3800 is disconnected from the patient's airway inlet, the leak resistance will be very low (i.e. close to a short circuit).

[0118] In one implementation, the controlled voltage source 6110 is servo-controlled to maintain a total flow Qt at or around a therapeutic flow Qth as the output voltage of the AC voltage source 6120 varies over a respiratory cycle (modeling a patient breath). In one implementation of servo control, the device pressure Pd varies around a steady (DC) pressure at the patient's 1000 respiratory rate per unit time in phase with the output of the AC voltage source 6120 (i.e., it drops during the inhalation portion and rises during the exhalation portion, and the total flow Qt remains constant at the therapeutic flow Qth throughout the respiratory cycle). This implementation can be modeled by replacing the controlled voltage source 6110 with a constant current source that supplies a current Qth. In another implementation of servo control, the device pressure Pd remains constant throughout the respiratory cycle, and the total flow Qt fluctuates around the therapeutic flow Qth in opposite phase with the output of the AC voltage source 6120 at the patient's 1000 respiratory rate per unit time (i.e., higher than the therapeutic flow Qth during the inhalation portion (when the AC voltage is negative) and lower than the therapeutic flow Qth during the exhalation portion (when the AC voltage is positive)). In another intermediate implementation of servo control, the total flow Qt fluctuates slightly in opposite phase with the output of the AC voltage source 6120 around the therapeutic flow Qth at the patient's 1000 respiratory rate per unit time (i.e., slightly higher than the therapeutic flow Qth during the inhalation portion and slightly lower than the therapeutic flow Qth during the exhalation portion). Meanwhile, the device pressure Pd fluctuates slightly in phase with the output of the AC voltage source 6120 around the steady pressure (i.e., slightly lower during the inhalation portion and slightly higher during the exhalation portion). In reality, regardless of implementation, the transducers 4270 used in the servo control implementation are imperfect, so there will be some but non-zero variation in breath rate per unit time in both device pressure Pd and total flow Qt. The servo control implementation will determine whether device pressure Pd predominates, total flow Qt predominates, or both signals predominate.

[0119] One objective of the disclosed algorithm for determining how to use high-flow therapy is to The number of breaths per unit time generated by 1000 patients using the device is within the band These variations in pressure Pd and / or total flow Qt may be detected. It is advantageous to make the implementation of the servo control substantially independent, since this implementation is carried out in accordance with the present invention. This is because the indicated high flow rate is not necessarily known to the algorithm that determines how to use it. Such fluctuations may occur if the patient 1000 is not using high flow therapy (e.g., an air circuit 4170 is blocked or disconnected from the patient's airway inlet. do not have.

[0120] 7a is a flow chart illustrating a method 7000 that may be used to implement an algorithm for determining high-flow therapy usage in accordance with one form of the present technology. Method 7000 is described below using a device pressure Pd. However, if appropriate thresholds are set, method 7000 will function effectively using a patient interface pressure Pm.

[0121] The method 7000 begins with step 7010. Step 7010 determines whether the total flow rate Qt exceeds a flow rate threshold. In one implementation, the flow rate threshold is 10 liters / min. Step 7010 is intended to determine whether the RT device 4000 is delivering air flow at a high flow rate. Reasons why a high flow rate may not be delivered include a condition in which the pressure generator 4140 is not working or has failed, or a condition in which the air circuit 4170 or the non-sealed patient interface 3800 is obstructed or blocked. If the total flow rate Qt does not exceed the flow rate threshold ("N"), the method 7000 proceeds to step 7070. Step 7070 returns a value of "false" to indicate that the patient 1000 is not using high flow therapy.

[0122] If the total flow Qt exceeds the flow threshold ("Y"), the method 7000 proceeds to step 7020. In step 7020, both the total flow Qt and the device pressure Pd are bandpass filtered to a respiratory rate variation or frequency range (breath rate band) that encompasses the limits of human respiratory rates. Step 7020 is intended to remove components of short-term variations in pressure and flow (i.e., variations at respiratory rates or frequencies above a typical respiratory rate). Such components are "noise" in the sense that they are not relevant to determining whether high-flow therapy is being used by the patient 1000. In one implementation, the upper cutoff frequency or frequency of the bandpass filter is 0.5 Hz (i.e., 0.5 breaths per second), which is approximately the upper limit of a human respiratory rate at rest. Step 7020 is also intended to remove all components of long-term variations (i.e., variations at rates or frequencies below a typical respiratory rate). In one implementation, the lower cutoff rate or frequency of the bandpass filter is 0.1 Hz, which is approximately the lower limit of the respiratory rate per unit time for humans at rest. The bandpass filtering of step 7020 is configured such that the average or steady-state values ​​of the bandpass filtered total flow Qt' and device pressure Pd' are unchanged from the respective values ​​of the total flow Qt and device pressure Pd.

[0123] As an alternative to using fixed upper and lower cutoff times or frequencies, the patient's breath rate per unit time may first be estimated in the bandpass filtering step 7020. This may be done, for example, by searching for the location of the highest peak in, for example, a Fourier transform (e.g., as determined by a fast Fourier transform algorithm) of the total flow Qt, the device pressure Pd, or the ratio of the total flow Qt to the device pressure Pd. This ratio is useful because it has a significant component in the breath rate per unit time regardless of servo control implementation. The location of the highest peak is an estimate of the patient's breath rate per unit time. The upper and lower cutoff times or frequencies of the bandpass filtering step 7020 may then be derived from the estimate of the breath rate per unit time. For example, the lower cutoff time or frequency may be half the estimate of the breath rate per unit time and the upper cutoff time or frequency may be twice the estimate of the breath rate per unit time.

[0124] As a further alternative to using fixed upper and lower cutoff times or frequencies in step 7020, patient height is used to determine appropriate upper and lower cutoff times or frequencies because patient height is related to the number of breaths per unit time of a person at rest by a well-known physiological relationship. Patient height may be input as a setting of the RT device 4000 via the input device 4220.

[0125] After step 7020, the only components of variation remaining in the bandpass filtered total flow Qt' and device pressure Pd' are those that lie within the band of breath rates defined by the cutoff frequency or frequency of the bandpass filter applied in step 7020 (equal to [0.1 Hz, 0.5 Hz] in one implementation described above). These components of variation within the band of breath rates are superimposed on the (positive) steady (average) values ​​of the total flow Qt and device pressure Pd.

[0126] In the next step 7030, the resistance to flow in the air circuit 4170 is calculated by dividing the bandpass filtered device pressure Pd' by the bandpass filtered total flow Qt'. Since the resistance to flow is calculated from the two bandpass filtered signals, the resistance to flow can also be considered as a bandpass filtered signal, even though it is not a direct result of the bandpass filtering.

[0127] Next, step 7035 determines whether the resistance to flow is within a predetermined range that is characteristic of a patient 1000 using high flow therapy. In one implementation, the predetermined range is 0.4 cmH 2 O / L / min ~ 0.9cmH 20 / liters / minute. If step 7035 determines that the resistance to flow is not within the predetermined range ("N"), method 7000 proceeds to step 7070 and returns a value of "false". The resistance to flow is substantially independent of the execution of the servo control being applied to the device pressure Pd from the RT device 4000. As described above, in one execution of the servo control, the total variation in the band of the respiratory rate is that of the device pressure Pd. In another execution of the servo control, the total variation in the band of the respiratory rate is that of the total flow Qt. In either execution, in all intermediate executions, the ratio of the device pressure Pd to the total flow Qt (resistance to flow) falls within the predetermined range as long as the patient 1000 is using high-flow therapy. However, this is not a sufficient condition for determining that high-flow therapy is being used, so if step 7035 determines that the resistance to flow is not within the predetermined range ("Y"), method 7000 proceeds to step 7040.

[0128] Steps 7040 and 7045 aim to determine whether the characteristics of the delivered airflow contain significant variation within the band of human breathing rates defined by the cutoff rate or frequency of step 7020. To do so, step 7040 calculates the magnitude of variation of one of the bandpass filtered signals over a sliding window of a given duration. In one implementation, step 7040 calculates the standard deviation of the bandpass filtered signal over a sliding window of one minute duration. This standard deviation is usable as it is insensitive to the average value over this window, and therefore encompasses the total variation within the window. Other implementations of step 7040 are listed below: Calculating the magnitude of fluctuations using the number of zero crossings of the mean-subtracted bandpass filtered signal over a sliding window; Calculating the power of the Fourier transform spectrum of the (unfiltered) signal in the band of respiratory rates per unit time calculated over a sliding window; Calculate the power of the Fourier transform spectrum of the (unfiltered) signal at harmonics of the band of breathing rates per unit time calculated over a window of predetermined duration, so that the harmonics (indicating, for example, the presence of snoring) are also indicative of the breathing of the patient 1000.

[0129] In one implementation of step 7040, suitable for an implementation in which the device pressure Pd remains constant throughout the respiratory cycle, the bandpass filtered signal is the bandpass filtered total flow Qt'. In another implementation of step 7045, suitable for an implementation in which the total flow Qt remains constant throughout the respiratory cycle, the bandpass filtered signal is the bandpass filtered device pressure Pd'. In yet another implementation of step 7045, suitable for an intermediate implementation of servo control, the bandpass filtered signal is the resistance to flow calculated in step 7030.

[0130] Then, step 7045 determines whether the magnitude of the variation in the bandpass filtered signal exceeds a magnitude threshold. In one implementation where the bandpass filtered signal is the bandpass filtered total flow rate Qt', the magnitude threshold is 10 liters / minute. If step 7045 determines that the magnitude of the variation in the bandpass filtered signal does not exceed the magnitude threshold ("N"), method 7000 proceeds to step 7070 and returns a value of "false."

[0131] If not ("Y" at step 7045), method 7000 proceeds to determine whether the magnitude of variation of the bandpass filtered signal itself (e.g., bandpass filtered total flow Qt') varies significantly as the sliding window over which the magnitude is calculated slides forward. Because respiratory demand typically changes slowly over time, the presence of such variation in the magnitude of variation of the bandpass filtered signal tends to confirm that high-flow therapy is being used by patient 1000. Therefore, step 7050 calculates the degree of the magnitude of variation of the bandpass filtered signal over a further sliding window of a predetermined duration. In one implementation, the further sliding window may be of the same duration as the sliding window over which the magnitude of variation of the bandpass filtered signal is calculated at step 7040. Step 7055 then determines whether the degree of variation of the magnitude of variation of the bandpass filtered signal exceeds a magnitude variation threshold. The magnitude variation threshold may be selected depending on the duration of the further sliding window. The longer the sliding window, the smaller the magnitude variation threshold should be selected. In one implementation, where the bandpass filtered signal is the bandpass filtered total flow Qt', a further sliding window is 1 minute in duration and has a spread of magnitude fluctuation degrees, and the flow magnitude fluctuation threshold is 0.002.

[0132] If step 7055 determines that the degree of variability in the variability magnitude of the bandpass filtered signal does not exceed the magnitude variability threshold ("N"), method 7000 proceeds to step 7070 and returns a value of "false" indicating that high flow therapy is not being used by patient 1000. Otherwise ("Y"), method 7000 proceeds to step 7060 and returns a value of "true" indicating that high flow therapy is being used by patient 1000.

[0133] In another implementation of the algorithm for determining high flow therapy usage, steps 7050 and 7055 may be omitted, and thus step 7060 is performed immediately following a "Y" response from step 7045. Thus, steps 7050 and 7055 may be optional.

[0134] In another implementation of the algorithm for determining high-flow therapy usage, steps 7040 and 7045 (and optionally 7050 and 7055) may be performed with respect to the device pressure Pd or resistance to flow calculated in step 7030, rather than with respect to the total flow Qt. In such an implementation, different thresholds are applied in step 7045 (and 7055, if present).

[0135] 8.4.3.2 High-Flow Therapy Monitoring In one form of the present technology, a high flow therapy monitoring algorithm receives as input a signal indicative of the pressure at the RT device outlet, Pd, and a signal indicative of the total flow rate of air delivered from the RT device 4000, Qt. The high flow therapy monitoring algorithm generates as output a time series of indications of the status of the high flow therapy at successive times. The status indication at any time may take one of several values, each of which indicates a different status of the high flow therapy (e.g., "in use", "not in use", "device inoperative", "air circuit occluded", and "air circuit disconnected"). Such status indication(s) may be stored in memory 426 or output for display on a user interface or display of the controller 4230 of the RT device 4000 that determines the indicator, or may be output for display on a user interface or display in communication with the controller 4230 of the RT device 4000 that determines the indicator.

[0136] As described above in connection with the algorithm for determining high-flow therapy usage, the high-flow therapy monitoring algorithm may be executed by the central controller 4230 of the RT device 4000, a processor of the remote external computing device 4286, or some combination of the two in “real-time” or as a post-process. Similarly, as described above in connection with the algorithm for determining high-flow therapy usage, the high-flow therapy monitoring algorithm may accumulate status readings as a chronological record of high-flow therapy status. The RT device 4000 may take different actions based on such status records. For example, in some cases, the status readings or accumulated records of status readings may be evaluated in the controller and serve as triggers for changes in operation of the controller 4230 of the RT device 4000. For illustrative purposes, if a sufficient number (e.g., a series) of status readings indicate non-use, occlusion, and / or disconnection, the controller 4230 may interrupt therapy (e.g., reduce or stop flow generation), for example, by altering the control operation of the blower motor 4144. Optionally, for example, if a sufficient number (e.g., a series) of status readings indicate an occlusion, the controller 4230 may increase therapy (e.g., increase flow generation, for example, by modifying the control operation of the blower motor).

[0137] 7b is a flow chart illustrating a method 7100 that may be used to implement a high-flow therapy monitoring algorithm in accordance with one form of the present technology. Method 7100 is described below using a device pressure Pd. However, if appropriate thresholds are set, method 7100 may function effectively using a patient interface pressure Pm.

[0138] Method 7100 is similar to method 7000 in that the steps in method 7100 and the relatively numbered steps in method 7000 (e.g., 7130 and 7030) are generally the same as the relatively numbered steps in method 7000, except as follows.

[0139] The first step 7110 determines whether the device pressure Pd is below a threshold value. A situation where the device pressure Pd is below the threshold value may occur when the pressure generator 4140 is not operating or has failed. In that case ("Y"), the method 7100 proceeds to step 7115, concludes the method 7100, and returns an indication value of the "device inoperative" state. Otherwise ("N"), the method 7100 proceeds to steps 7120 and 7130. Steps 7120 and 7130 are the same as steps 7020 and 7030 as described above.

[0140] After step 7130, step 7133 checks whether the resistance to flow is too low (i.e., lower than the lower end of the range used in step 7035, which is equal to 0.4 cmH 2 O / liter / min) in one run. If so ("Y"), the method 7100 proceeds to step 7137, concludes the method 7100, and returns an indication value of the "connection disconnected" state for the indicator. This value indicates that the unsealed patient interface 3800 is disconnected from the airway of the patient 1000, thereby reducing the leakage resistance 6140 in the circuit model 6100.

[0141] Otherwise (in step 7133, "N"), the method 7100 proceeds to step 7138 and checks whether the resistance to flow is too high (i.e., higher than the upper end of the range used in step 7035, which is equal to 0.9 cmH 2 O / liter / min) in one run. If so ("Y"), the method 7100 proceeds to step 7139, concludes the method 7100, and returns an indication value of the "obstruction" state for the indicator. This value indicates the possibility that the air circuit 4170 is blocked. Otherwise ("N"), the method 7100 proceeds to step 7140. Step 7140 is the same as step 7040 as described above.

[0142] In a variation of method 7100, after test 7138, a second test (not shown) of the value of the resistance to flow is performed. If this value is above the "high" threshold and below the threshold used in step 7138, a further step may return an indication value of "cannula too big", thereby indicating that the cannula projection is close to sealing inside the patient's 1000 nose.

[0143] Step 7170 may be reached if the test at step 7145 or the test at step 7155 fails (which may occur, for example, if patient 1000 is choking for an extended period of time or has blocked nasal passages). Step 7170 returns a value of "Not in Use" for the status indication to indicate that patient 1000 is not using high-flow therapy. Step 7160 is reached if the test at step 7155 passes and returns a value of "In Use" for the status indication to indicate that patient 1000 is using high-flow therapy.

[0144] In a variation of the method 7100 for monitoring high flow therapy, instead of the "return" steps 7115, 7137 and 7139 returning "device not operational", "disconnected" and "occluded", respectively, a test may be performed for each of its status indications. For example, step 7137 may initiate a separate test to disconnect the unsealed patient interface 3800 from the patient 1000 instead of returning a status indication of "disconnected".

[0145] 8.4.3.3 Calibration of the circuit model The circuit model 6100 may be generalized so that the air circuits, interfaces and leak paths are not modeled by linear resistances 6130, 6150 and leakage resistances 6140 respectively, but by respective non-linear impedances whose pressure drop depends non-linearly on the flow rate of air passing therethrough. To characterize each of these impedances, a multi-stage calibration may be taken. In each stage, at least two different values ​​of steady-state device pressure Pd are applied and corresponding measurements of total flow Qt are made. The applied values ​​and measurements are used to adjust a polynomial relating the pressure drop over the impedance to the flow rate passing therethrough. The following series of calibration stages may be used, each of which lists the configurations of the air circuits and the corresponding impedances that may be characterized thereby. The impedances characterized by each stage allow the next stage of calibration / characterization. Interface disconnected from air circuit: air circuit impedance corresponding to resistive element 6130. Interface connected to the air circuit and disconnected from the patient: interface impedance corresponding to resistive element 6150. · Interface connected to air circuit and patient, patient "self-occlusion": leakage impedance corresponding to resistive element 6140.

[0146] 8.4.3.4 Estimation of patient parameters It may be of diagnostic interest to infer parameters of the patient 1000 (e.g., airway resistance 6125, lung compliance 6135, airway "inertance" modeled by the circuit model 6100) from inductors (not shown) in series with these elements and parameters derivable from these values ​​(e.g., lung resonant frequency (equal to the inverse of the square root of the product of inertance and compliance divided by 2π) and damping (equal to resistance divided by inertance divided by 2π). To infer such parameters, the source 6110 may have a more "active" component superimposed on its servo control value, whether the servo control value is constant or varies in number of breaths per unit time as described above. This active component may include, for example, impulses, slopes, variations at specific frequencies or broadband noise. The resulting response of the total flow Qt together with the active component of the device pressure Pd is analyzed to generate an estimate of one or more of the above patient parameters. This process is greatly aided if the non-patient elements (6130, 6150 and 6140) of the circuit model 6100 have been characterized by calibration as described above.

[0147] 8.4.3.5 Two-nostril model 6c is a circuit diagram of an electrical circuit model 6200 that forms a more advanced model of a RT device that delivers high flow therapy to a breathing patient 1000 via an unsealed patient interface 3800. The electrical circuit model 6200 includes elements 6210, 6220, 6225, 6230, and 6235 that are the same as their respective counterparts 6110, 6120, 6120, 6125, 6130, and 6135 in the electrical circuit model 6100. However, the circuit model 6200 splits the interface resistance 6150 into two separate resistances 6250a and 6250b that model the left and right nasal protuberances, respectively, of the unsealed patient interface 3800. The leakage resistance 6140 is also split into left and right nostril leakage resistances 6240a and 6240b, respectively. The variations in resistances 6260a and 6260b model the resistances of the left and right nasal passages, respectively. The total flow Qt is divided into a flow Qa through the left lobe and a flow Qb through the right lobe.

[0148] If the nasal passage resistances 6260a and 6260b are very small, the model 6200 is simplified to the model 6100 with an interface resistance 6150 equal to the parallel resistances 6250a and 6250b, and a leakage resistance 6140 equal to the parallel left and right nostril leakage resistances 6240a and 6240b. However, the above does not apply if any of the nasal passage resistances 6260a and 6260b are not negligible, for example due to nasal circulation. The above-described method of usage determination and monitoring is also applicable to the two-nostril model 6200 for determining usage and status indications at a given time, but can be implemented with different thresholds than those described above. However, to characterize the individual nostrils and leakage resistances at any given time, the above-described multi-step calibration process needs to be refined: Interface disconnected from air circuit: air circuit impedance corresponding to resistive element 6230. Interface connected to air circuit and disconnected from patient, right leg occlusion: left leg impedance corresponding to resistive element 6250a. Interface connected to air circuit and disconnected from patient, left prong occlusion: right prong impedance corresponding to resistive element 6250b. · Air circuit and interface connected to patient, patient with right nostril "self-occluded", : leakage impedance of left nostril corresponding to resistive element 6240a. · Air circuit and interface connected to patient, patient with left nostril "self-occluded": leakage impedance of right nostril corresponding to resistive element 6240b.

[0149] After adding an "active" component to the source 6110 with each nostril self-occluded, analysis of the active component and the resulting total flow Qt allows one to infer the left and right nasal passage impedances corresponding to resistive element 6260a and resistive element 6260b, respectively, along with other patient parameters at any given time.

[0150] 8.5 Humidifier In one form of the present technology, a humidifier 5000 (e.g., as shown in FIG. 5a) is provided to change the absolute humidity relative to atmospheric air of air or gas for delivery to a patient. Typically, the humidifier 5000 is used to increase the absolute humidity and increase the temperature (relative to atmospheric air) of the air stream prior to delivery to the patient's airways.

[0151] The humidifier 5000 may include a humidifier reservoir 5110, a humidifier inlet 5002 for receiving a flow of air, and a humidifier outlet 5004 for delivering a flow of humidified air. In some forms, the inlet and outlet of the humidifier reservoir 5110 may be the humidifier inlet 5002 and the humidifier outlet 5004, respectively, as shown in FIG. 5a and FIG. 5b. The humidifier 5000 may further include a humidifier base 5006. The humidifier base 5006 may be adapted to receive the humidifier reservoir 5110 and include a heating element 5240. The humidifier reservoir 5110 may include an electrically conductive region 5120. The electrically conductive region 5120 is configured to allow effective heat transfer from the heating element 5240 to the volume of liquid in the reservoir 5110. The humidifier reservoir 5110 may include a water level indicator 5150.

[0152] In one form, the humidifier 5000 may include a humidifier reservoir dock 5130 configured to receive the humidifier reservoir 5110. In some arrangements, the humidifier reservoir dock 5130 may include a locking feature, such as a locking lever 5135 configured to retain the reservoir 5110 within the humidifier reservoir dock 5130.

[0153] 8.6 Glossary For purposes of this disclosure, in certain aspects of the present technology, one or more of the following definitions may apply. In other aspects of the present technology, other definitions may apply.

[0154] 8.6.1 General Air: In certain forms of the present technology, air may refer to atmospheric air, while in other forms of the present technology, air may refer to combinations of other breathable gases (e.g., oxygen-rich atmospheric air).

[0155] Respiratory pressure therapy: the delivery of air to the entrance to the airways at a therapeutic pressure that is continuously positive relative to atmosphere.

[0156] Nasal Continuous Positive Airway Pressure (CPAP) Therapy: Respiratory pressure therapy in which the therapeutic pressure is approximately constant throughout the patient's respiratory cycle. In some forms, the pressure at the entrance to the airway increases slightly during expiration and decreases slightly during inspiration. In some forms, the pressure varies during different respiratory cycles of the patient (e.g., increased in response to the detection of an indication of partial upper airway obstruction and decreased in the absence of an indication of partial upper airway obstruction).

[0157] Patient: A person with or without a respiratory disease.

[0158] Automatic positive airway pressure (APAP) therapy: In response to the presence or absence of indications of SDB episodes For example, CPAP therapy, which allows the therapeutic pressure to be continuously adjusted between minimum and maximum limits between breaths.

[0159] 8.6.2 Phases of the Respiratory Cycle Asphyxiation: According to some definitions, asphyxiation is said to occur when flow below a certain threshold continues for a duration of, for example, 10 seconds. Obstructive asphyxiation is said to refer to a condition in which the airway is obstructed and air cannot flow despite the patient's efforts. Central apnea is said to refer to a condition in which asphyxiation is detected due to a reduced or absent effort to breathe despite a patent airway. Mixed asphyxiation is said to refer to a condition in which a reduced or absent effort to breathe occurs simultaneously with an obstructed airway.

[0160] Breaths per unit time: The number of spontaneous breaths a patient takes per unit of time, usually measured in breaths per minute.

[0161] Duty cycle: The ratio of inhalation time Ti to total breathing time Ttot.

[0162] Effort (respiratory): Respiratory effort is said to refer to the movement made by a person's spontaneous breathing as they try to breathe.

[0163] Expiratory portion of the respiratory cycle: the period from the start of the expiratory flow to the start of the inspiratory flow.

[0164] Flow limitation: Flow limitation refers to a condition in a patient's breathing when an increase in the patient's effort does not result in a corresponding increase in flow. If flow limitation occurs during the inspiratory portion of the respiratory cycle, it may be described as inspiratory flow limitation. If flow limitation occurs during the expiratory portion of the respiratory cycle, it may be described as expiratory flow limitation.

[0165] Hypopnea: Preferably, hypopnea refers to a reduction in flow, rather than an interruption of flow. In one form, hypopnea is said to occur when there is a sustained period of reduced flow below a threshold rate. When hypopnea is detected due to a reduction in respiratory effort, central hypopnea is said to occur. In one form in adults, hypopnea may be considered when any of the following occur: (i) A 30% decrease in patient respiration for at least 10 seconds plus associated 4% desaturation, or; (ii) A reduction in patient respiration (less than 50%) lasting for at least 10 seconds and associated with at least 3% desaturation or arousal occurs.

[0166] Hyperventilation: An increase in flow to a level higher than normal.

[0167] Inspiration portion of the respiratory cycle: The period from the start of the inspiratory flow to the start of the inspiratory flow is taken as the inspiration portion of the respiratory cycle.

[0168] Patency (Airway): The degree to which the airway is open or the extent to which the airway is open. A patent airway is open. Airway patency may be quantified by one of the following values: (1) open, a value of zero (0), closed (obstructed).

[0169] Positive End-Expiratory Pressure (PEEP): The pressure above atmosphere in the lungs that exists at the end of expiration.

[0170] Peak flow (Q peak): The maximum value of flow during the inspiratory portion of the respiratory flow waveform.

[0171] Respiratory flow, airflow, patient airflow, respiratory airflow (Qr): These synonymous terms may be understood to refer to the RT device's estimate of the respiratory airflow and are used in contrast to "true respiratory flow" or "true respiratory airflow," which is the patient's actual respiratory flow, usually expressed in liters / minute.

[0172] Tidal Volume (Vt): The volume of air inhaled or exhaled during normal breathing without extra effort.

[0173] (Inhalation) Time (Ti): The duration of the inspiratory portion of the respiratory flow waveform.

[0174] (Expiratory) Time (Te): The duration of the expiratory portion of the respiratory flow waveform.

[0175] (Total) Time (Ttot): The total duration between the start of the inspiratory portion of one respiratory flow waveform and the start of the inspiratory portion of the next respiratory flow waveform.

[0176] Typical Recent Ventilation: Ventilation values ​​over a given time scale tend to cluster together (i.e., the degree to which recent values ​​of ventilation tend to be central).

[0177] Upper Airway Obstruction (UAO): Includes both partial and total upper airway obstruction. May be associated with a state of flow limitation in which flow levels may increase or decrease slightly with increasing pressure differential over the upper airway (Starling resistor behavior).

[0178] Ventilation: The measure of the total amount of gas exchanged by a patient's respiratory system. The measure of ventilation may include one or both of the inhalation and exhalation flows per unit time. When expressed as a volume per minute, this quantity is often called "minute ventilation." Minute ventilation is sometimes given simply as volume, but is understood as volume per minute.

[0179] 8.6.3 RT Deviceparameters Flow Rate: The instantaneous volume (or mass) of air delivered per unit time. ("Flow rate" is sometimes simply referred to as "flow"). Flow rate and ventilation have the same dimensional volume or mass per unit time, but flow rate is measured over a much shorter period of time. In some cases, when referring to flow rate, it refers to a scalar quantity (i.e., a quantity that has only magnitude). In other cases, when referring to flow rate, it refers to a vector quantity (i.e., a quantity that has both magnitude and direction). When referred to as a signed quantity, flow rate can be nominally positive for the inhalation portion of the patient's respiratory cycle, and negative for the exhalation portion of the patient's respiratory cycle. Total flow rate Qt is the flow rate of air delivered from the RT device.

[0180] Pressure: force per unit area. Pressure can be measured in a range of units (e.g., cmH 2 O, gf / cm 2 , hectopascal. 1cmH 2 O is 1g-f / cm 2 (Equivalent to approximately 0.98 hectopascals). In this specification, unless otherwise specified, pressure is expressed in cmH 2 The pressure in the patient interface (patient interface pressure) is given by the symbol Pm and the pressure at the outlet of the RT device (device pressure) is given by the symbol Pd.

[0181] 8.7 Other Considerations A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the reproduction by any person of this patent document or the patent disclosure by facsimile, for purposes of disclosure in the Patent and Trademark Office patent file or records, but reserves all copyright rights thereto for all other purposes.

[0182] Unless otherwise clearly indicated from the context and unless a range of values ​​is provided, it is understood that each intervening value between the upper and lower limits of the range, the unit of the lower limit, and any other stated or intervening value of the stated range is encompassed by the technology. The upper and lower limits of these intervening ranges, which are independently included in the intervening range, are also encompassed by the technology if they specifically exceed the limits in the stated range. If the stated range includes one or both of these limits, then ranges exceeding either or both of these stated limits are also encompassed by the technology.

[0183] Furthermore, where a value or values ​​are presented herein as part of the present technology, unless otherwise indicated, it is understood that such values ​​may be approximated and may be used to any appropriate significant figures to the extent practical technical practice permits or requires.

[0184] Unless otherwise specified, all technical and scientific terms herein have the same meaning as commonly understood by one of ordinary skill in the art to which this technology belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of this technology, a limited number of exemplary methods and materials are described herein.

[0185] Although particular materials are described as being preferred for use in the construction of components, obvious alternative materials having similar properties may be substituted. Further, unless stated to the contrary, any and all components described herein are understood to be manufacturable and therefore may be manufactured collectively or separately.

[0186] It should be noted that, as used herein, in the appended claims, the singular forms "a," "an," and "the" include their plural equivalents unless the context clearly indicates otherwise.

[0187] All publications mentioned herein are incorporated by reference to disclose and describe the methods and / or materials that are the subject of these publications. Publications mentioned herein are provided solely for their disclosure prior to the filing date of this application. Nothing herein should be construed as an admission that the present technology does not antedate such publications by virtue of prior patents. Furthermore, the dates of publications mentioned may differ from the actual publication dates, which may require independent confirmation.

[0188] Moreover, in interpreting this disclosure, all terms should be interpreted in the broadest reasonable manner under the context. In particular, the terms "comprises" and "comprising" should be interpreted as referring to elements, components, or steps in an exclusive sense, indicating that a described element, component, or step may be present in, utilized with, or combined with other elements, components, or steps not specifically recited.

[0189] The headings used in the detailed description are for the convenience of the reader and should not be used to limit the content found in the disclosure or claims as a whole. These headings should not be used in interpreting the scope of the claims or the limitations of the claims.

[0190] Although the technology herein has been described with reference to certain embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the technology. In some cases, terms and symbols may indicate specific details that are not necessary for the implementation of the technology. For example, the terms "first" and "second" are used, but unless otherwise specified, these terms are not intended to indicate any order, but are used to distinguish separate elements. Furthermore, although the description or illustration of the process steps in the method may be described in an order, such order is not necessary. Those skilled in the art will recognize that such order can be changed and / or the aspects can be performed simultaneously or even synchronously.

[0191] It is therefore to be understood that numerous modifications are possible in the illustrative examples and that other arrangements may be devised without departing from the spirit and scope of the present technology. The claims as originally filed are as follows: Claim 1: 1. A method for determining whether high flow therapy is being used by a patient, the method comprising: evaluating one or more signals in a controller associated with a respiratory therapy device to determine whether a characteristic of a flow of air being delivered from the respiratory therapy device along a pneumatic circuit to a non-sealed patient interface includes significant variation within a band of respiratory rates per unit time; and generating an output indication in the controller based on said determining whether high flow therapy is being used by the patient. Claim 2: 2. The method of claim 1, wherein the generating step generates the output indication that high flow therapy is being used by the patient when a determination is made that the characteristic includes significant variation within a band of respiratory rates per unit time. Claim 3: Said determining: calculating a magnitude of variation within said respiratory rate band of said characteristic signal over a window of predetermined duration; and determining whether the magnitude of the variation is greater than a magnitude threshold. Claim 4: The method of claim 3, wherein the calculating step includes applying a bandpass filter to the signal having cutoff rates that are approximately upper and lower limits of a human's respiratory rate per unit time at rest. Claim 5: The method of claim 4 , wherein the magnitude of the variation is the standard deviation of the window. Claim 6: 4. The method of claim 3, wherein the calculating comprises calculating a power of a Fourier transform spectrum of the signal over the window within a band of the respiratory rate per unit time. Claim 7: 4. The method of claim 3, further comprising determining whether a magnitude of the variation in the signal varies significantly as the window slides forward, and wherein said generating is further based on said determining. Claim 8: The method of claim 7, wherein when it is determined that the magnitude of the variation has changed significantly as the window slides forward, the generating generates the output indication indicating that high flow therapy is being used by the patient. Claim 9: Said determining: calculating a degree of variation of the magnitude of the variation over a further window of predetermined duration; and determining whether the degree of variation is greater than a magnitude variation threshold. Claim 10: The method of claim 9 , wherein the measure of variation is variance. Claim 11: 11. The method according to claim 1, wherein the characteristic of the air flow is a total flow rate of the air flow. Claim 12: 11. The method of claim 1, further comprising calculating a resistance to flow from a total flow rate of the air stream and a pressure of the air stream. Claim 13: The method of claim 12 , wherein the characteristic of the air flow is a resistance to the flow. Claim 14: determining whether the resistance to flow is within a predetermined range; The method of claim 12 , wherein the generating is further based on the determining. Claim 15: 15. The method of claim 14, wherein if the resistance to flow is determined not to be within the predetermined range, the generating generates the output indication indicating that high flow therapy is not being used by the patient. Claim 16: 15. The method of claim 14, wherein said generating comprises generating the output indication that the air circuit is disconnected if the resistance to flow is determined to be below a lower limit of the predetermined range. Claim 17: 15. The method of claim 14, wherein said generating comprises generating the output indication that the air circuit is occluded if the resistance to flow is determined to be above an upper limit of the predetermined range. Claim 18: 15. The method of claim 14, further comprising, if the resistance to flow is determined to be above an upper limit of the predetermined range, generating, at the controller, an output indication that the patient interface is too large based on the determination. Claim 19: The calculation includes: applying a bandpass filter to the total flow and the pressure having cutoff rates that are approximately upper and lower limits of the respiratory rate of a human at rest to generate a bandpass filtered device pressure and a bandpass filtered total flow; and dividing the bandpass filtered device pressure by the bandpass filtered total flow. Claim 20: 20. The method of claim 19, wherein the pressure is a pressure at an outlet of the respiratory therapy device. Claim 21: repeating said generating output readings to generate a plurality of generated output readings of usage of high flow therapy; 21. The method of claim 1, further comprising accumulating the generated output indications of the high flow therapy usage over time into a record of the high flow therapy usage over time for the patient. Claim 22: 22. The method of claim 21, further comprising generating a compliance report based on the record of usage of the high flow therapy. Claim 23: 22. The method of claim 21, further comprising adjusting parameters of the high-flow therapy based on the record of usage of the high-flow therapy. Claim 24: 24. The method of claim 23, wherein the parameter is a therapeutic flow rate. Claim 25: 22. The method of claim 21, further comprising generating an alert based on the record of usage of the high flow therapy. Claim 26: 26. The method of claim 1, further comprising comparing the airflow characteristic to a threshold, and wherein said generating is further based on said determining. Claim 27: 27. The method of claim 26, wherein the characteristic is a total flow rate of the airflow, and wherein generating generates the output indication that high flow therapy is not being used by the patient if the total flow rate is determined to be below a flow rate threshold. Claim 28: 27. The method of claim 26, wherein the characteristic is a pressure of the airflow, and wherein generating comprises generating the output indication that the respiratory therapy device is not operating if the pressure is determined to be below a pressure threshold. Claim 29: 29. The method of claim 1, further comprising estimating the number of breaths per unit time from the signal indicative of said characteristic. Claim 30: 2. The method of claim 1, further comprising controlling, by the controller, a change in operation of the respiratory therapy device based on the output indication of whether high flow therapy is being used by the patient. 29. The method according to any one of claims 29 to 30. Claim 31: 31. The method of claim 30, wherein a change in operation of the respiratory therapy device changes a characteristic of the airflow delivered from the respiratory therapy device. Claim 32: 1. An apparatus for delivering high flow therapy to a patient, the apparatus comprising: a servo-controlled blower configured to generate a flow of air along the air circuit to the unsealed patient interface; a central controller configured to control the servo-controlled blowers; one or more transducers configured to generate one or more signals indicative of respective characteristics of the generated airflow; A processor comprising: receiving said one or more signals; controlling a determination whether the airflow characteristic indicated by one of the one or more signals includes significant variation within a band of breathing rates per unit time; and and a processor configured to generate an indication of whether high flow therapy is being used by the patient in response to the determination. Claim 33: The method of claim 32 , wherein the processor is the central controller. Claim 34: The method of claim 32 , wherein the processor is located in a remote external computing device configured to communicate with the central controller. Claim 35: 1. An apparatus for delivering high flow therapy to a patient, the apparatus comprising: flow means for generating a flow of air along the air circuit to the unsealed patient interface; means for controlling said flow means; means for generating one or more signals indicative of respective characteristics of said air flows being generated; means for receiving said one or more signals; means for determining whether the airflow characteristic indicated by one of the one or more signals includes significant variation within a band of respiratory rates per unit time; and means for generating an indication of whether high flow therapy is being used by said patient in response to said determining. Claim 36: 1. A high flow therapy system comprising: with an unsealed patient interface; an air circuit configured to be connected to the unsealed patient interface; a servo-controlled blower configured to generate a flow of air along the air circuit; a central controller configured to control the servo-controlled blowers; one or more transducers configured to generate one or more signals indicative of respective characteristics of the generated airflow; A processor comprising: receiving said one or more signals; controlling a determination whether the airflow characteristic indicated by one of the one or more signals includes significant variation within a band of breathing rates per unit time; and and a processor configured to generate an indication of whether high flow therapy is being used by the patient in response to the determination. [Explanation of symbols]

[0192] patient 1000 Bedmate 1100 Patient Interface 3000 Closed formation structure 3100 Cavity room 3200 Structure 3300 Ventilation hole 3400 Connection port 3600 Forehead support part 3700 Unsealed Patient Interface 3800 nasal protrusion 3810 nasal protrusion 3810 Lumens 3820 Lumens 3820 RT Device 4000 External housing 4010 Upper part 4012 Part 4014 Panel 4015 Chassis 4016 Handle 4018 Pneumatic Block 4020 Pneumatic Components 4100 Air Filter 4110 Inlet Air Filter 4112 Outlet Air Filter 4114 Inlet muffler 4122 Exit muffler 4124 Pressure Generator 4140 Blower 4142 Motor 4144 Air Circuit 4170 Extra oxygen 4180 Electrical Components 4200 Printed Circuit Board Assembly 4202 power supply 4210 Input Devices 4220 Central Controller 4230 Clock 4232 Therapy device controller 4240 Protection circuit 4250 Memory 4260 Transducer 4270 Pressure Sensor 4272 Flow Transducer 4274 Motor Speed ​​Transducer 4276 Data communication interface 4280 Remote external communication network 4282 Local external communication network 4284 Remote External Computing Device 4286 Local Foreign Device 4288 Output device 4290 Display driver 4292 Display 4294 Algorithm 4300 Therapy control module 4330 Humidifier 5000 Humidifier inlet 5002 Humidifier outlet 5004 Humidifier Base 5006 Humidifier Reservoir 5110 Conductive part 5120 Humidifier Reservoir Dock 5130 Lock lever 5135 Water Level Indicator 5150 heating element 5240 Humidifier Controller 5250 Electrical Circuit Model 6000 Voltage Source 6010 AC Voltage Source 6020 Airway Resistance 6025 Air circuit resistance 6030 Pulmonary Compliance 6035 Interface resistance 6050 Electrical Circuit 6100 Voltage Source 6110 AC Voltage Source 6120 Airway Resistance 6125 Air circuit resistance 6130 Pulmonary Compliance 6135 Leakage resistance 6140 Interface resistance 6150 Electrical Circuit 6200 Voltage Source 6210 AC Voltage Source 6220 Airway Resistance 6225 Air circuit resistance 6230 Pulmonary Compliance 6235 Left nostril leakage impedance 6240a Right nostril leakage impedance 6240b Left protrusion impedance 6250a Right protrusion impedance 6250b Left nasal passage impedance 6260a Right nasal passage impedance 6260b method 7000 Step 7010 Step 7020 Step 7030 Step 7035 Step 7040 Step 7045 Step 7050 Step 7055 Step 7060 Step 7070 Method 7100 Step 7110 Step 7115 Step 7120 Step 7130 Step 7133 Step 7137 Step 7138 Step 7139 Step 7140 Step 7145 Step 7155 Step 7160 Step 7170

Claims

1. 1. A method of a remote processor for determining whether high flow therapy from a high flow therapy device is being used by a patient, comprising: receiving data generated by the high flow therapy device via remote communication, the data being pressure information and total flow information; calculating a resistance to flow of a flow of air being delivered by the high flow therapy device along an air circuit to an unsealed patient interface based on the pressure information and the total flow information, and determining whether a characteristic of the flow of air being delivered by the high flow therapy device along the air circuit to the unsealed patient interface includes significant variation within a band of respiratory rates per unit time, wherein the characteristic of the flow of air is the calculated resistance to flow; generating an output indication of whether high flow therapy is being used by the patient based on said determining; Including, The method, wherein the generating step generates an output indication indicating that high flow therapy is being used by the patient when a determination is made that the characteristic includes significant variation within the band of respiratory rate per unit time.

2. The determining step comprises: calculating a magnitude of variation within said respiratory rate band of said characteristic signal over a window of predetermined duration; determining whether the magnitude of the variation is greater than a magnitude threshold; The method of claim 1 , comprising:

3. 3. The method of claim 2, wherein calculating the magnitude of the fluctuations comprises applying a bandpass filter to the signal having cutoff rates that are approximately upper and lower limits of the respiratory rate per unit time of a human at rest.

4. The method of claim 3 , wherein the magnitude of the variation is the standard deviation of the window.

5. 3. The method of claim 2, wherein calculating the magnitude of the fluctuations comprises calculating the power of a Fourier transform spectrum of the signal over the window within the band of the respiratory rate per unit time.

6. The method of claim 2 , further comprising determining whether a magnitude of the variation in the signal varies significantly as the window slides forward, and wherein said generating is further based on said determining.

7. The method of claim 6, wherein if it is determined that the magnitude of the variation has changed significantly as the window slides forward, the generating generates the output indication indicating that high flow therapy is being used by the patient.

8. The determining step comprises: calculating a degree of variation of the magnitude of the variation over a further window of predetermined duration; determining whether the degree of variability is greater than a magnitude variability threshold; The method of claim 6, comprising:

9. The method of claim 8 , wherein the measure of variation is a variance.

10. The method of any one of claims 1 to 9, wherein said total flow information is a total flow of said air stream and said pressure information is a pressure of said air stream.

11. determining whether the resistance to flow is within a predetermined range; The method of any one of claims 1 to 10, wherein said generating is further based on said determining.

12. 12. The method of claim 11, wherein if the resistance to flow is determined not to be within the predetermined range, the generating generates the output indication indicating that high flow therapy is not being used by the patient.

13. 12. The method of claim 11, wherein said generating comprises generating the output indication that the air circuit is disconnected if the resistance to flow is determined to be below a lower limit of the predetermined range.

14. The method of claim 11 , wherein said generating comprises generating the output indication that the air circuit is occluded if the resistance to flow is determined to be above an upper limit of the predetermined range.

15. 12. The method of claim 11, further comprising, if the resistance to flow is determined to be above an upper limit of the predetermined range, generating an output indication that the patient interface is too large based on the determination.

16. The calculating step comprises: applying a bandpass filter to the total flow and the pressure having cutoff rates that are approximately upper and lower limits of the respiratory rate of a human at rest to generate a bandpass filtered device pressure and a bandpass filtered total flow; Dividing the bandpass filtered device pressure by the bandpass filtered total flow rate; The method of claim 10, comprising:

17. 17. The method of claim 16, wherein the pressure is the pressure at the outlet of the high flow therapy device.

18. repeating said generating output readings to generate a plurality of generated output readings of usage of high flow therapy; storing the generated output indications of the high flow therapy usage over time in a record of the high flow therapy usage over time for the patient; The method of any one of claims 1 to 9, further comprising:

19. 20. The method of claim 18, further comprising generating a compliance report based on the record of usage of the high flow therapy.

20. 20. The method of claim 18, further comprising adjusting parameters of the high-flow therapy based on the record of usage of the high-flow therapy.

21. The method of claim 20, wherein the parameter is a therapeutic flow rate.

22. 20. The method of claim 18, further comprising generating an alert based on the record of usage of the high flow therapy.

23. The method of any one of claims 1 to 9, further comprising comparing a characteristic of the air flow to a threshold, and wherein said generating is further based on said determining.

24. 24. The method of claim 23, wherein the characteristic is a total flow rate of the airflow, and wherein generating generates the output indication that high flow therapy is not being used by the patient if the total flow rate is determined to be below a flow rate threshold.

25. 25. The method of claim 24, wherein the characteristic is a pressure of the air flow, and wherein generating generates the output indication that the high flow therapy device is not operating if the pressure is determined to be below a pressure threshold.

26. The method of any one of claims 1 to 9, further comprising inferring the number of breaths per unit time from the signal indicative of said characteristic.

27. The method of any one of claims 1 to 9, wherein the output indications include a generated time series of usage indications of whether high flow therapy is being used by the patient at successive times.

28. 30. The method of claim 27, further comprising determining usage of high flow therapy by accumulating the usage indications.

29. 1. An apparatus for determining whether high flow therapy from a high flow therapy device is being used by a patient, comprising: receiving data generated by the high flow therapy device via remote communication, the data being pressure information and total flow information; controlling a calculation of a resistance to flow of an air flow being delivered by the high flow therapy device along an air circuit to an unsealed patient interface based on the pressure information and the total flow information; and controlling a determination whether a characteristic of the air flow being delivered by the high flow therapy device along the air circuit to the unsealed patient interface includes significant variation within a band of respiratory rates per unit time, wherein the characteristic of the air flow is the calculated resistance to flow; generating an output indication of whether high flow therapy is being used by the patient in response to said determining. a processor configured to: The output reading indicates that high flow therapy is being used by the patient when a determination is made that the characteristic includes significant variation within the band of respiratory rate per unit time.

30. 1. A system for delivering high flow therapy to a patient, comprising: flow means for generating a flow of air along the air circuit to the unsealed patient interface; means for controlling said flow means; means for generating a plurality of signals indicative of respective characteristics of the air streams being generated, said plurality of signals including a signal indicative of a total flow rate of the air streams and a signal indicative of a pressure of the air streams; means for receiving said plurality of signals via remote communication; means for calculating a resistance to flow of the air stream based on the signal indicative of the total flow rate of the air stream and the signal indicative of a pressure of the air stream, and determining whether the characteristic of the air stream includes significant variation within a band of respiratory rates per unit time, wherein the characteristic of the air stream is the calculated resistance to flow; means for generating an indication of whether high flow therapy is being used by said patient in response to said determining. Including, The indication is indicative that high flow therapy is being used by the patient when a determination is made that the characteristic includes significant variation within the band of respiratory rate per unit time.

31. 1. A high flow therapy system comprising: a non-sealed patient interface; an air circuit configured to be connected to the unsealed patient interface; a servo-controlled blower configured to generate a flow of air along the air circuit; a central controller configured to control the servo-controlled blowers; one or more transducers configured to generate a plurality of signals indicative of respective characteristics of the airflow being generated, wherein the plurality of signals includes a signal indicative of a total flow rate of the airflow and a signal indicative of a pressure of the airflow; a processor configured to receive the signals via remote communication; control a calculation of a resistance to flow of the air flow based on the signal indicative of the total flow rate of the air flow and the signal indicative of a pressure of the air flow; and control a determination of whether the characteristic of the air flow includes significant variation within a band of respiratory rates per unit time, where the characteristic of the air flow is the calculated resistance to flow, and in response to the determination, generate an indication of whether high flow therapy is being used by the patient. Including, the indication being indicative of high flow therapy being used by the patient when a determination is made that the characteristic includes significant variation within the band of respiratory rate per unit time; The system, wherein the processor is located in a remote external computing device configured to communicate with the central controller.

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