Acoustic component identification for respiratory therapy systems

Abstract

A processor associated with a respiratory treatment device (7040) applies acoustic techniques, e.g., for airway component identification. The device can include a pressure generator configured to generate a supply of pressurized air from an outlet along an air circuit to a patient interface. The device can include a sensor configured to generate a sound signal representative of sound of the pressure generator in the air circuit. The device can include a sound absorbing structure configured to reduce reflections of sound from the pressure generator along the air circuit. A processor, e.g., of a controller, can be configured to process the sound signal to identify the patient interface and / or the air circuit. The processing can detect and combine acoustic signatures, e.g., by aligning and averaging, and / or can flatten a spectrum of the sound signal.

Description

[0001] 1 Cross-reference to related applications

[0002] This application claims the benefit of Australian Provisional Application No. 2019901502 filed on 2 May 2019, the entire disclosure of which is incorporated herein by reference. 2 Background Technology 2.1 Technical Field

[0005] The present technology relates to one or more of the detection, diagnosis, treatment, prevention, and improvement of respiratory-related conditions. The present technology also relates to medical devices or equipment and their uses. For example, devices of the present technology may implement acoustic technology, such as for component identification and / or control of such devices to produce treatment.

[0006] 2.2 Description of Related Technology

[0007] 2.2.1 Human respiratory system and its disorders

[0008] The body's respiratory system facilitates gas exchange. The nose and mouth form the entrances to a person's airways.

[0009] The airway comprises a series of branch tubes, and when the branch trachea penetrates deeper into the lungs, it becomes narrower, shorter and more numerous. The main function of the lungs is gas exchange, thereby allowing oxygen to enter the venous blood from the inhaled air and to expel carbon dioxide in the opposite direction. The trachea is divided into the left main bronchus and the right main bronchus, which are eventually divided into terminal bronchioles. The bronchi constitute the conducting airways and do not participate in gas exchange. Further branches of the airway lead to the respiratory bronchioles and eventually to the alveoli. The alveolar region of the lungs is the area where gas exchange occurs and is called the respiratory zone. Referring to " Respiratory Physiology (Respiratory Physiology)" published by John B.West, Lippincott Williams & Wilkins in 2012, the 9th edition.

[0010] There are a range of respiratory disorders. Some disorders can be characterized by specific events such as apnea, hypopnea, and hyperpnea.

[0011] Obstructive sleep apnea (OSA) is a sleep-disordered breathing (SDB) characterized by events including occlusion or obstruction of the upper airway during sleep. This is caused by the abnormally small upper airway in the tongue, soft palate, and posterior oropharyngeal wall area during sleep, coupled with the normal loss of muscle tone. The disease causes the affected patient to stop breathing, typically for periods of 30 to 120 seconds, sometimes 200 to 300 times per night. It often leads to excessive daytime sleepiness and may cause cardiovascular disease and brain damage. Although the affected person may not be aware of the problem, the syndrome is a disorder that is particularly common in middle-aged overweight men. Referring to U.S. Patent No. 4,944,310 (Sullivan).

[0012] A range of treatments have been used to treat or ameliorate these conditions. Furthermore, such treatments can be used to prevent breathing problems in otherwise healthy individuals. However, these have a number of drawbacks.

[0013] 2.2.2 Treatment

[0014] Various therapies, such as continuous positive airway pressure (CPAP) therapy, high flow therapy (HFT), non-invasive ventilation (NIV), and invasive ventilation (IV) have been used to treat one or more of the above-mentioned breathing disorders.

[0015] 2.2.3 Treatment system

[0016] These respiratory therapies can be provided by a therapy system or device.Such systems and devices can also be used to diagnose a condition without treating it.

[0017] A respiratory therapy system may include a respiratory therapy device (RT device), an air circuit, a humidifier, a patient interface, and data management.

[0018] 2.2.3.1 Patient interface

[0019] The patient interface can be used to couple the respiratory apparatus to its wearer, for example by providing an air flow to the entrance of the airway. The air flow can be provided to the patient's nose and / or mouth via a mask, to the patient's mouth via a tube, or to the patient's trachea via a tracheostomy tube. Depending on the treatment to be applied, the patient interface can form a seal with an area of ​​the patient's face, for example, to facilitate the delivery of gas at a pressure that is sufficiently different from the ambient pressure (e.g., a positive pressure of approximately 10 cmH2O relative to the ambient pressure) to achieve the treatment. For other forms of treatment, such as oxygen delivery, the patient interface may not include a seal sufficient to facilitate the delivery of a gas supply at a positive pressure of approximately 10 cmH2O to the airway.

[0020] 2.2.3.2 Respiratory therapy (RT) devices

[0021] Respiratory therapy (RT) devices, such as respiratory pressure therapy (RPT) devices, can be used to deliver one or more of the various therapies described above, such as by generating an air flow for delivery to an airway entrance. The air flow can be pressurized. Examples of RPT devices include CPAP devices and ventilators. In some cases, the respiratory therapy (RT) device can be a high flow therapy (HFT) device that provides high flow respiratory therapy.

[0022] Air pressure generators are known in the field of applications such as industrial-scale ventilation systems. However, air pressure generators for medical applications have specific requirements that are not met by more general air pressure generators, such as reliability, size and weight requirements for medical devices.

[0023] Examples of RPT devices include the S9 sleep therapy system manufactured by ResMed Limited, ventilators such as the ResMed Stellar TM A series of adult and pediatric ventilators and ResMed Astral TM 150 ventilators.

[0024] 2.2.3.3 Humidifier

[0025] Delivering an air stream without humidification can lead to airway drying. Using a humidifier with an RT device and patient interface to generate humidified gas minimizes drying of the nasal mucosa and increases patient airway comfort. Additionally, in colder climates, warm air, typically applied to the facial area in and around the patient interface, is more comfortable than cold air.

[0026] 2.2.3.4 Vent Technology

[0027] Some forms of respiratory therapy systems may include a vent to allow removal of exhaled carbon dioxide. The vent may allow gas to flow from the interior space of the patient interface (eg, a plenum) to the exterior of the patient interface (eg, to the surrounding environment).

[0028] 2.2.3.5 Sensing and Data Management

[0029] Patients, caregivers, clinicians, insurance companies, or technicians may wish to collect data related to respiratory therapy, whether it is related to the patient, the individual components used for therapy, or the therapy system as a whole. There are many situations during the provision of respiratory therapy to a patient where one or more of the parties involved can benefit from collecting therapy-related data and utilizing the collected data.

[0030] In particular, some components of a respiratory therapy system need to be replaced at a higher frequency than other components to provide effective treatment. For example, some patients may replace a patient interface that includes a silicone seal forming part every few months (e.g., 3 months), while the RT device may be replaced or upgraded every few years (e.g., 3 years). For those components that will be replaced at relatively frequent intervals (e.g., the patient interface), patients or caregivers often face challenges in obtaining reliable and accurate notification at low cost when their components are about to be replaced. When a new component is replaced, the new component may require the patient or caregiver to change one or more settings in the treatment system (e.g., software settings in the RT device) to ensure that the system takes full advantage of the new component. Therefore, the ability to identify components of a respiratory therapy system is important for both optimizing treatment and keeping patients and caregivers informed of replacement schedules.

[0031] In the past, a range of solutions have been employed or proposed in the field of respiratory therapy related to component identification. For example, sensors / transducers have been used and proposed in various forms to collect data related to environmental conditions, patient identification, component identification, treatment operating conditions, and the like. In practice, many RT devices include one or more sensors, such as flow sensors, pressure sensors, humidity sensors, temperature sensors, and the like. The signals generated by such sensors can be analyzed to generate treatment-related data, such as the identity of a specific component (e.g., a patient interface) within a respiratory therapy system.

[0032] However, sensors / transducers often require a suite of additional components, which can hinder their adoption in many forms. For example, data collected by the sensors / transducers must then be transferred for storage and / or analysis, such as from the sensor to a memory device and / or processor. This and the aforementioned sensors can further increase design, testing, and / or manufacturing costs for medical device manufacturers and / or can increase costs and complexity for patients.

[0033] Furthermore, integrating expensive electrical and / or mechanical features into frequently replaced components (eg, a patient interface) may not be conducive to providing the most cost-effective treatment and may be environmentally unsustainable due to increased waste.

[0034] Furthermore, many proposed solutions related to sensors and / or transducers may be limited because, if the proposed sensors are located remotely from where their data is to be stored and / or analyzed, this may generally further increase implementation complexity and / or cost. For example, where the patient interface includes a sensor, electrical connections to the RT device may be required, which may further increase implementation complexity and / or cost.

[0035] Furthermore, designers of RT devices face numerous choices, often resulting in different solutions compared to other devices on the market (e.g., competitors', or those manufactured by the same manufacturer but at different times). Consequently, the associated electrical connectors provided may only be capable of connecting to a specific RT device. This can create unintended incompatibilities, potentially adversely impacting specific consumer segments, and / or reduce consumer choice. 3 Summary of the invention

[0037] The present technology is directed to providing medical devices for diagnosing, ameliorating, treating, or preventing breathing disorders with improved one or more of comfort, cost, efficacy, ease of use, patient management, and manufacturability.

[0038] A first aspect of the present technology relates to an apparatus for diagnosing, ameliorating, treating or preventing a respiratory disorder.

[0039] Another aspect of the present technology relates to methods for diagnosing, ameliorating, treating or preventing breathing disorders.

[0040] One aspect of the present technology relates to an improved respiratory therapy device that is configured to acoustically identify components of a respiratory therapy system of which it is a part. In particular, the disclosed device includes structures and processes configured to analyze acoustic reflections from system components to identify those components based on their "acoustic signatures" in a more accurate manner than previously known. This improvement can be achieved at least in part by implementing one or more structures that reduce back reflections of sound from the device end of an air circuit, which can, for example, improve the distinguishability of acoustic signatures of different patient interface types. This improvement can also be achieved at least in part by signal processing that "flattens" the frequency spectrum (e.g., the logarithmic spectrum) of the acoustic signal, for example, before conversion to an acoustic signature.

[0041] Some implementations of the present technology may include a device for generating respiratory therapy. The device may include a pressure generator configured to generate a supply of pressurized air from an outlet along an air circuit to a patient interface. The device may include a sensor configured to generate an acoustic signal representative of the sound of the pressure generator in the air circuit. The device may include a sound absorbing structure configured to reduce reflections of sound from the pressure generator along the air circuit. The device may include a controller. The controller may be configured to process the acoustic signal to identify the patient interface and / or the air circuit.

[0042] In some implementations, the sound-absorbing structure can be formed by a through-hole sound-absorbing conduit configured to change the acoustic impedance between the air circuit and the cavity of the pressure generator's housing. The sound-absorbing structure defines or can be defined by a cross-section of a passage through the through-hole sound-absorbing conduit, such that the cross-section expands along the path of the passage due to the contour of the inner surface of the through-hole sound-absorbing conduit. The cross-section can gradually expand as it moves further away from the patient interface end of the air circuit. The device can include a waveguide formed by at least the outlet and the air circuit, wherein the sound-absorbing structure can be located along the waveguide between the sensor and the outlet, and wherein the sensor can be located along the waveguide between the sound-absorbing structure and the air circuit. The sound-absorbing structure can be formed by a horn. The horn can have a conical profile.

[0043] Some implementations of the present technology may include a method, in a processor associated with a respiratory therapy device, for identifying a component of an air path coupled to the respiratory therapy device. The method may include processing an acoustic signal representing sound in the air path to obtain a cepstrum. The processing may include flattening the spectrum of the acoustic signal. The processing may include separating an acoustic signature from the cepstrum. The processing may include comparing the acoustic signature to a set of predetermined acoustic signatures corresponding to each component. The processing may include identifying the component based on the comparison of the acoustic signature to the set.

[0044] In some implementations, flattening can include removing a low-pass filtered version of the logarithmic spectrum of the sound signal from the logarithmic spectrum of the sound signal. The removal can include subtraction. The method can also include repeating the processing and separation at least once to produce a plurality of acoustic signatures. The method can also include combining the plurality of acoustic signatures into a combined acoustic signature. The comparison can compare the combined acoustic signature to a combination of predetermined acoustic signatures. The combining can include aligning one or more of the plurality of acoustic signatures with the combined acoustic signature. The combining can include averaging the plurality of acoustic signatures. The component can be a patient interface, and the repetitions can be synchronized with the respiratory cycle of a patient wearing the patient interface. The combining can be robust to small variations in delays between the plurality of acoustic signatures. The method can include adjusting control parameters for the operation of a pressure generator of the respiratory therapy device based on the identification.

[0045] Some implementations of the present technology may include a device for generating respiratory therapy. The device may include a pressure generator configured to generate a pressurized air supply from an outlet along an air circuit to a patient interface. The device may include a sensor configured to generate an acoustic signal representing the sound of the pressure generator in the air circuit. The device may include a controller. The controller may be configured to process the acoustic signal to obtain a cepstrum. The processing may include flattening the spectrum of the acoustic signal. The controller may be configured to separate an acoustic signature from the cepstrum. The controller may be configured to compare the acoustic signature with a set of predetermined acoustic signatures corresponding to each component. The controller may be configured to identify the patient interface and / or the air circuit based on the comparison of the acoustic signature with the set.

[0046] In some implementations, the device can include a sound-absorbing structure configured to reduce reflections of sound from the pressure generator along the air circuit. The sound-absorbing structure can be formed by a through-going sound-absorbing conduit configured to change the acoustic impedance between the air circuit and the cavity of the housing of the pressure generator. The sound-absorbing structure can be formed by a horn. The horn can have a conical profile. The controller can also be configured to adjust control parameters of the pressure generator's operation based on the identified patient interface and / or air circuit.

[0047] Some implementations of the present technology may include a method, in a processor associated with a respiratory therapy device, for identifying a component of an air path coupled to the respiratory therapy device. The method may include processing an acoustic signal representing sound in the air path to obtain a cepstrum. The method may include separating an acoustic signature from the cepstrum. The method may include repeating the processing and separation at least once to produce a plurality of acoustic signatures. The method may include combining the plurality of acoustic signatures into a combined acoustic signature. The method may include comparing the combined acoustic signature to a combination of predetermined acoustic signatures corresponding to the components. The method may include identifying the component based on the comparison of the acoustic signature to the set.

[0048] In some implementations, combining can include aligning one or more of the plurality of acoustic signatures with the combined acoustic signature. Combining can include averaging the plurality of acoustic signatures. The component can be a patient interface. The repetition can be synchronized with a breathing cycle of a patient wearing the patient interface. Combining can be robust to variations in delays between the plurality of acoustic signatures. Processing can include flattening the spectrum of the acoustic signal. Flattening can include subtracting a low-pass filtered version of the logarithmic spectrum of the acoustic signal from the logarithmic spectrum of the acoustic signal. The method can include adjusting a control parameter of an operation of a pressure generator of the respiratory therapy device based on the identification.

[0049] Some implementations of the present technology may include a computer-readable medium having encoded thereon computer-readable instructions that, when executed by a processor of a controller of a respiratory therapy device, cause the processor to perform a method as described herein, or any one or more aspects thereof.

[0050] Some implementations of the present technology may include a device for generating respiratory therapy. The device may include a pressure generator configured to generate a pressurized air supply from an outlet along an air circuit to a patient interface. The device may include a sensor configured to generate an acoustic signal representing the sound of the pressure generator in the air circuit. The device may include a controller. The controller may be configured to process the acoustic signal to obtain a cepstrum. The controller may be configured to separate an acoustic signature from the cepstrum. The controller may be configured to repeat the processing and separation at least once to generate a plurality of acoustic signatures. The controller may be configured to combine the plurality of acoustic signatures into a combined acoustic signature. The controller may be configured to compare the combined acoustic signature with a combination of predetermined acoustic signatures corresponding to the components. The controller may be configured to identify the patient interface and / or the air circuit based on the comparison of the acoustic signature with the set.

[0051] In some implementations, the device can include a sound absorbing structure configured to reduce reflections of sound from the pressure generator along the air circuit. The sound absorbing structure can be formed by a through-going sound absorbing conduit configured to change the acoustic impedance between the air circuit and the cavity of the housing of the pressure generator. The sound absorbing structure can be formed by a horn. The horn can have a conical profile. To combine the multiple acoustic signatures, the controller can be configured to align one or more of the multiple acoustic signatures with the combined acoustic signature. To combine the multiple acoustic signatures, the controller can be configured to average the multiple acoustic signatures. The controller can also be configured to adjust control parameters of the operation of the pressure generator based on the identified patient interface and / or air circuit.

[0052] The methods, systems, devices, and apparatus described herein can provide improved functionality in processors, such as dedicated computers, respiratory monitors, and / or respiratory therapy devices. Furthermore, the methods, systems, devices, and apparatus described herein can provide improvements in the art of automated management, monitoring, and / or treatment of respiratory conditions, including, for example, sleep-disordered breathing.

[0053] Of course, a portion of these aspects may form sub-aspects of the present technology. Sub-aspects and / or various aspects of an aspect may be combined in various ways and also constitute other aspects or sub-aspects of the present technology.

[0054] Other features of the technology will become apparent upon consideration of the information contained in the following detailed description, abstract, drawings, and claims. 4 Description of the accompanying drawings

[0056] The present technology is illustrated by way of example and not limitation in the figures of the accompanying drawings in which like reference numerals refer to like elements, including:

[0057] 4.1 Treatment System

[0058] Figure 1A A system is shown that includes a patient 1000 wearing a patient interface 3000 in the form of nasal pillows and receiving a supply of air at positive pressure from an RPT device 4000. The air from the RPT device 4000 is humidified in a humidifier 5000 and flows along an air circuit 4170 to the patient 1000. A bed partner 1100 is also shown. The patient sleeps in a supine position.

[0059] Figure 1B A system is shown that includes a patient 1000 wearing a patient interface 3000 in the form of a nasal mask receiving a supply of air at positive pressure from an RPT device 4000. The air from the RPT device is humidified in a humidifier 5000 and delivered to the patient 1000 along an air circuit 4170.

[0060] Figure 1C A system is shown that includes a patient 1000 wearing a patient interface 3000 in the form of a full face mask, receiving a supply of air at positive pressure from an RPT device 4000. The air from the RPT device is humidified in a humidifier 5000 and delivered along an air circuit 4170 to the patient 1000. The patient sleeps in a side-lying position.

[0061] 4.2 Respiratory system and facial anatomy

[0062] Figure 2 Shown is a schematic diagram of the human respiratory system including the nasal and oral cavities, larynx, vocal cords, esophagus, trachea, bronchi, lungs, alveolar sacs, heart, and diaphragm.

[0063] 4.3 Patient Interface

[0064] Figure 3 An example of a patient interface in the form of a nasal mask in accordance with one form of the present technology is shown.

[0065] 4.4RPT device

[0066] Figure 4A Shown is an exploded view of an exemplary respiratory pressure therapy (RPT) device 4000 in accordance with one form of the present technology.

[0067] Figure 4Bis a schematic diagram of a pneumatic path of an RPT device according to one form of the technology. Upstream and downstream directions are indicated.

[0068] 4.5 Humidifier

[0069] Figure 5A is an isometric view of a humidifier according to one form of the technology.

[0070] Figure 5B shows an isometric view of a humidifier according to one form of the technology showing a humidifier reservoir 5110 removed from a humidifier reservoir base 5130.

[0071] 4.6 Breathing Waveform

[0072] Figure 6 A model typical breathing waveform of a human at rest is shown. The horizontal axis is time and the vertical axis is respiratory flow rate. While the parameter values can vary, a typical breath can have the following approximate values: tidal volume, Vt, 0.5 L, inspiration time, Ti, 1.6 s, peak inspiratory flow rate, Q 峰值 , 0.4 L / s, expiration time, Te, 2.4 s, peak expiratory flow rate, Q 峰值 , -0.5 L / s. The total duration of the breath, T 总 , is approximately 4 s. A human typically breathes at a rate of approximately 15 breaths per minute (BPM), and the minute ventilation, Vent, is approximately 7.5 L / min. The typical duty cycle, Ti to T 总 , is approximately 40%.

[0073] 4.7 Acoustic Analysis

[0074] Figure 7 is a schematic diagram of a respiratory therapy system according to one aspect of the technology.

[0075] Figure 8 is a plot of an example of a pulse response function of a respiratory therapy system including Figure 7 ;

[0076] Figure 9 is a plot of cepstrums of different example masks in a respiratory therapy system including Figure 7 ;

[0077] Figure 10 is a plot of a cepstrum including a back-reflection component;

[0078] Figure 11 is a schematic diagram of a respiratory therapy system according to one aspect of the technology;

[0079] Figure 11A and Figure 11Bshows an outline of an exemplary through-going sound absorbing duct for use in some implementations of the present technology;

[0080] Figure 12 is a flow chart illustrating a method for identifying components of an air path of a respiratory therapy system according to one aspect of the present technology;

[0081] Figure 13 Contains two graphs showing the acoustic signature before and after alignment. 5. Specific Implementation Methods

[0083] Before describing the present technology in further 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 terminology used in this disclosure is for the purpose of describing the specific examples described herein only and is not intended to be limiting.

[0084] The following description is provided for various examples that may share one or more common characteristics and / or features. It should be understood that one or more features of any example may be combined with one or more features of other examples. Additionally, in any instance, any single feature or combination of features may constitute a further example.

[0085] 5.1 Treatment

[0086] In one form, the present technology comprises a method for treating a breathing disorder comprising the step of applying positive pressure to an airway entrance of a patient 1000 .

[0087] 5.2 Treatment System

[0088] In one form, the present technology includes a system for treating a respiratory disorder.A respiratory therapy (RT) system may include an RPT device 4000 for delivering a supply of air at positive pressure to a patient 1000 via a humidifier 5000, an air circuit 4170, and a patient interface 3000.

[0089] 5.3 Patient Interface

[0090] like Figure 3 The exemplary non-invasive patient interface 3000 shown includes the following functional aspects: a seal-forming structure 3100, an inflatable chamber 3200, a positioning and stabilizing structure 3300, a vent 3400, a connection port 3600 for connecting to a form of air circuit 4170, and a forehead support 3700. In some forms, the functional aspects may be provided by one or more physical components. In some forms, one physical component may provide one or more functional aspects. In use, the seal-forming structure 3100 is arranged to surround the entrance to the patient's airway to facilitate the supply of positive pressure air to the airway.

[0091] A patient interface 3000 according to one form of the present technology is constructed and arranged to provide a supply of air at a positive pressure of, for example, at least 4 cmH2O, or at least 10 cmH2O, or at least 20 cmH2O, or at least 25 cmH2O relative to ambient.

[0092] 5.3.1 Sealing structure

[0093] In one form of the present technology, the seal-forming structure 3100 provides a target seal-forming area and may additionally provide a cushioning function. The target seal-forming area is the area on the seal-forming structure 3100 where sealing is likely to occur. The area where sealing actually occurs—the actual sealing surface—can vary within a given treatment session, from day to day, and from patient to patient, depending on a number of factors, including, for example, where the patient interface is placed on the face, the tension in the positioning and stabilizing structure, and the shape of the patient's face.

[0094] 5.3.2 Inflatable chamber

[0095] In the area where the seal is formed when in use, the inflatable chamber 3200 has a periphery that is shaped to complement the surface contour of the average person's face. When in use, the boundary edge of the inflatable chamber 3200 is positioned so as to be in close proximity to the adjacent surface of the face. The seal-forming structure 3100 provides actual contact with the face. The seal-forming structure 3100 can extend around the entire periphery of the inflatable chamber 3200 when in use. In some forms, the inflatable chamber 3200 and the seal-forming structure 3100 are formed from a single homogeneous piece of material. The acoustic generator 8500 can be formed as part of the inflatable chamber 3200 or pass through the housing of the inflatable chamber 3200.

[0096] 5.3.3 Positioning and stabilizing the structure

[0097] The seal-forming structure 3100 of the patient interface 3000 of the present technology may be maintained in a sealed state during use by the positioning and stabilizing structure 3300 .

[0098] 5.3.4 Ventilation

[0099] In one form, the patient interface 3000 includes a vent 3400 constructed and arranged to allow clearance of exhaled gases, such as carbon dioxide.

[0100] In certain forms, the vent 3400 is configured to allow continuous ventilation flow from the interior of the plenum chamber 3200 to the surrounding environment while the pressure within the plenum chamber is positive relative to the surrounding environment. The vent 3400 is configured so that the vent flow rate has a sufficient amplitude to reduce the patient's rebreathing of exhaled CO2 while maintaining a therapeutic pressure in the plenum chamber during use. One form of the vent 3400 according to the present technology includes a plurality of holes, for example, about 20 to about 80 holes, or about 40 to about 60 holes, or about 45 to about 55 holes.

[0101] The vent 3400 may be located in the plenum 3200. Alternatively, the vent 3400 is located in a decoupling structure, such as a swivel.

[0102] 5.3.5 Connection Port

[0103] The connection port 3600 allows connection to the air circuit 4170 and may optionally include an integrated acoustic generator 8500 .

[0104] 5.4RPT device

[0105] A respiratory pressure therapy (RPT) device 4000 according to one aspect of the present technology is Figure 4A 4300. The RPT device 4000 is shown in an exploded view, includes mechanical, pneumatic, and / or electronic components, and is configured to execute one or more algorithms 4300. The RPT device 4000 can be configured to generate a flow of air for delivery to the airway of a patient, such as for treating one or more respiratory conditions described elsewhere in this document.

[0106] In one form, the RPT device 4000 is constructed and arranged to deliver air flow in the range of -20 L / min to +150 L / min while maintaining a positive pressure of at least 4 cmH2O, or at least 10 cmH2O, or at least 20 cmH2O, or at least 25 cmH2O.

[0107] The RPT device 4000 can have an outer housing 4010 comprised of two parts: an upper portion 4012 and a lower portion 4014. Furthermore, the outer housing 4010 can include one or more panels 4015. The RPT device 4000 can include a chassis 4016 that supports one or more internal components of the RPT device 4000. The RPT device 4000 can include a handle 4018.

[0108] The pneumatic path of the RPT device 4000 may include one or more air path items, such as an inlet air filter 4112, an inlet muffler 4122, a pressure generator 4140 capable of supplying positive pressure air (e.g., a blower 4142), an outlet muffler 4124, and one or more transducers 4270, such as a pressure sensor and a flow sensor.

[0109] One or more air path items may be disposed within a removable, separate structure, which will be referred to as an aerodynamic block 4020. The aerodynamic block 4020 may be disposed within the outer housing 4010. In one form, the aerodynamic block 4020 is supported by, or forms part of, the chassis 4016.

[0110] The RPT 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 converter 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 an alternative form, the RPT device 4000 may include more than one PCBA 4202.

[0111] 5.4.1 Mechanical and pneumatic components of the RPT device

[0112] The RPT device may comprise one or more of the following components in an integral unit. In an alternative form, one or more of the following components may be provided as separate units.

[0113] 5.4.1.1 Pressure generator

[0114] In one form of the present technology, the pressure generator 4140 for generating a downstream air flow, such as an air flow or air supply under positive pressure, is a controllable blower 4142. The blower can be capable of supplying air at a positive pressure of about 4 cmH2O to about 20 cmH2O, or in other forms at a positive pressure of up to about 30 cmH2O, for example, at a rate of up to about 120 liters / minute. The blower can be as described in any of the following patents or patent applications, which are incorporated herein by reference in their entirety: U.S. Patent No. 7,866,944; U.S. Patent No. 8,638,014; U.S. Patent No. 8,636,479; and PCT Patent Publication No. WO 2013 / 020167.

[0115] The pressure generator 4140 is controlled by the treatment device controller 4240.

[0116] In other words, the pressure generator 4140 can be a piston-driven pump, a pressure regulator connected to a high pressure source (e.g., a compressed air reservoir), or a bellows.

[0117] 5.4.1.2 Memory

[0118] According to one form of the present technology, the RPT device 4000 includes memory 4260, such as 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.

[0119] Memory 4260 may be located on PCBA 4202. Memory 4260 may be in the form of EEPROM or NAND flash memory.

[0120] Additionally or alternatively, the RPT device 4000 includes memory 4260 in a removable form, such as a memory card made in accordance with the Secure Digital (SD) standard.

[0121] In one form of the present technology, the memory 4260 acts as a non-transitory computer-readable storage medium on which are stored computer program instructions or processor control instructions expressing one or more methods described herein, such as one or more algorithms 4300.

[0122] 5.4.1.3 Data Communication System

[0123] In one form of the present technology, a data communication interface 4280 is provided and connected to the central controller 4230. The data communication interface 4280 can be connected to a remote external communication network 4282 and / or a local external communication network 4284. The remote external communication network 4282 can be connected to a remote external device 4286. The local external communication network 4284 can be connected to a local external device 4288.

[0124] 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 comprise an integrated circuit or processor.

[0125] In one form, remote external communication network 4282 is the Internet. Data communication interface 4280 may connect to the Internet using wired communication (eg, via Ethernet or fiber optics) or wireless protocols (eg, CDMA, GSM, LTE).

[0126] In one form, the local external communication network 4284 utilizes one or more communication standards, such as Bluetooth or consumer infrared protocols.

[0127] In one form, the remote external device 4286 is one or more computers, such as a cluster of network computers. In another form, the remote external device 4286 can be a virtual computer rather than a physical computer. In either case, such a remote external device 4286 can be accessed by appropriately authorized individuals, such as clinicians.

[0128] The local external device 4288 may be a personal computer, a mobile computing device such as a smart phone or tablet device, or a remote control.

[0129] 5.4.2RPT device algorithm

[0130] As noted above, in some forms of the present technology, central controller 4230 may be configured to implement one or more algorithms 4300 represented as computer programs stored in a non-transitory computer-readable storage medium such as memory 4260. Algorithms 4300 are generally grouped into groups called modules.

[0131] 5.5 Humidifier

[0132] 5.5.1 Humidifier Overview

[0133] In one form of the present technology, the RT system includes a circuit located between the RPT device 4000 and the air circuit 4170 (e.g., Figure 4A ) between the humidifier 5000 to change the absolute humidity of the air delivered to the patient relative to the absolute humidity of the surrounding air. Typically, the humidifier 5000 is used to increase the absolute humidity and increase the temperature of the air flow (relative to the ambient air) before delivery to the patient's airway.

[0134] Humidifier 5000 (e.g., Figure 5A ) may include a humidifier reservoir 5110, a humidifier inlet 5002 for receiving an air flow, and a humidifier outlet 5004 for delivering a humidified air flow. In some forms, such as Figure 5A and 5B As shown, the inlet and outlet of the humidifier reservoir 5110 can be respectively a humidifier inlet 5002 and a humidifier outlet 5004. The humidifier 5000 can also include a humidifier base 5006, which can be adapted to receive the humidifier reservoir 5110 and include a heating element 5240.

[0135] 5.5.2 Humidifier components

[0136] 5.5.2.1 Water reservoir

[0137] According to one arrangement, the humidifier 5000 may include a water reservoir 5110 configured to hold or retain a volume of liquid (e.g., water) to be evaporated for humidifying the air flow. The water reservoir 5110 may be configured to hold a predetermined maximum volume of water to provide adequate humidification for at least the duration of a respiratory therapy session, such as one night of sleep. Typically, the reservoir 5110 is configured to hold several hundred milliliters of water, for example, 300 milliliters (ml), 325 ml, 350 ml, or 400 ml. In other forms, the humidifier 5000 may be configured to receive a water supply from an external water source, such as a building water supply.

[0138] According to one aspect, water reservoir 5110 is configured to add humidity to the airflow from RPT device 4000 as the airflow travels therethrough. In one form, water reservoir 5110 may be configured to force the airflow to travel in a tortuous path through reservoir 5110 while in contact with the water content therein.

[0139] According to one form, the reservoir 5110 may be arranged, for example, along Figure 5A and Figure 5B Sideways orientation shown for removal from humidifier 5000.

[0140] The reservoir 5110 can also be configured to prevent liquid from flowing out of it, such as through any holes and / or between its subcomponents, such as when the reservoir 5110 is displaced and / or rotated from its normal operating orientation. Since the air flow to be humidified by the humidifier 5000 is generally pressurized, the reservoir 5110 can also be configured to avoid aerodynamic pressure loss through leakage and / or flow resistance.

[0141] 5.5.2.2 Conductive part

[0142] According to one arrangement, the reservoir 5110 includes a conductive portion 5120 that is configured to allow efficient transfer of heat from the heating element 5240 to the liquid volume in the reservoir 5110. In one form, the conductive portion 5120 can be configured as a plate, but other shapes are also suitable. All or a portion of the conductive portion 5120 can be made of a thermally conductive material, such as aluminum (e.g., having a thickness of approximately 2 mm, such as 1 mm, 1.5 mm, 2.5 mm, or 3 mm), another thermally conductive metal, or some plastics. In some cases, suitable thermal conductivity can be achieved using a material with a suitable geometry that has a lower conductivity.

[0143] 5.5.2.3 Humidifier reservoir dock

[0144] In one form, the humidifier 5000 may include a humidifier reservoir base 5130 (e.g., Figure 5B), which is configured to receive the humidifier reservoir 5110. In some arrangements, the humidifier reservoir base 5130 can include a locking feature, such as a locking lever 5135 configured to retain the reservoir 5110 in the humidifier reservoir base 5130.

[0145] 5.5.2.4 Water level indicator

[0146] The humidifier reservoir 5110 may include Figures 5A to 5B Water level indicator 5150 is shown. In some forms, water level indicator 5150 can provide a user (e.g., patient 1000 or a caregiver) with one or more indications regarding the amount of water contained in humidifier reservoir 5110. The one or more indications provided by water level indicator 5150 can include an indication of a maximum predetermined capacity of water, any fraction thereof, such as 25%, 50%, 75%, or a capacity such as 200 ml, 300 ml, or 400 ml.

[0147] 5.5.2.5 Humidifier Converter

[0148] The humidifier 5000 may include one or more humidifier transducers (sensors) 5210 instead of or in addition to the transducer 4270 described above. The humidifier transducer 5210 may include one or more of an air pressure sensor 5212, an air flow transducer 5214, a temperature sensor 5216, or a humidity sensor 5218. The humidifier transducer 5210 may generate one or more output signals that may be communicated to a controller (such as the central controller 4230 and / or the humidifier controller 5250). In some embodiments, the humidifier transducer may be provided externally to the humidifier 5000 (such as in the air circuit 4170) while communicating the output signals to the controller 5250.

[0149] 5.6 Air circuit

[0150] The air circuit 4170 according to one aspect of the present technology is a conduit or tube that is constructed and arranged to allow a flow of pressurized air to travel between two components, such as a humidifier 5000 and a patient interface 3000 , in use.

[0151] Specifically, the air circuit 4170 can be fluidly connected to the outlet 5004 of the humidifier 5000 and the plenum 3200 of the patient interface 3000 .

[0152] 5.7 Converter

[0153] The RT system may include one or more transducers (sensors) 4270 configured to measure one or more of any number of parameters related to the RT system, its patient, and / or its environment. The transducers may be configured to generate output signals representing the one or more parameters that the transducers are configured to measure.

[0154] The output signal may be one or more of an electrical signal, a magnetic signal, a mechanical signal, a visual signal, an optical signal, an acoustic signal, or any number of other signals known in the art.

[0155] The converter may be integrated with another component of the RT system, with an exemplary arrangement being that the converter is internal to the RPT device.The converter may be essentially a 'stand-alone' component of the RT system, with an exemplary arrangement being that the converter is external to the RPT device.

[0156] The converter can be configured to transmit its output signal to one or more components of the RT system, such as an RPT device, a local external device, or a remote external device. The external converter can be located, for example, on a patient interface, or in an external computing device such as a smart phone. The external converter can be located, for example, on an air circuit (e.g., a patient interface) or form part of an air circuit (e.g., a patient interface).

[0157] One or more transducers 4270 can be constructed and arranged to generate signals representing properties of air, such as flow, pressure, or temperature. The air can be airflow from the RPT device to the patient, airflow from the patient to the atmosphere, ambient air, or any other air. These signals can represent properties of the airflow at a particular point, such as airflow in the pneumatic path between the RPT device and the patient. In one form of the present technology, one or more transducers 4270 are located in the pneumatic path of the RPT device, such as downstream of the humidifier 5000.

[0158] 5.7.1 Pressure Sensor

[0159] According to one aspect of the present technology, one or more transducers 4270 include a pressure sensor in fluid communication with the pneumatic path. An example of a suitable pressure sensor is a transducer from the Honeywell ASDX series. Another suitable pressure sensor is a transducer from the General Electric NPA series. In one implementation, the pressure sensor is located in the air circuit 4170 adjacent to the outlet 5004 of the humidifier 5000.

[0160] Pressure sensor (microphone) 4270 is configured to generate an acoustic signal representing pressure changes within air circuit 4170. The acoustic signal from microphone 4270 can be received by central controller 4230 for sound processing and analysis configured by one or more algorithms 4300 described below. Microphone 4270 can be directly exposed to the air path to be more sensitive to sound, or can be encapsulated behind a thin layer of flexible membrane material. The membrane can be used to protect microphone 4270 from heat and / or moisture.

[0161] 5.8 Acoustic Analysis

[0162] In accordance with one or more aspects of the present technique, acoustic analysis may be used to determine one or more parameters associated with a breathing disorder or a system for treating a breathing disorder.

[0163] Acoustic analysis according to aspects of the present technology may provide one or more advantages over existing technologies, such as reducing the cost of care, providing higher quality treatment, improving ease of use of treatment systems, reducing waste, and providing digital connectivity at low cost.

[0164] As will be apparent from the context of the remainder of this document, the terms "acoustics," "sound," or "noise" in this document are generally intended to include airborne vibrations, whether audible or inaudible. Thus, unless specifically stated otherwise, the terms "acoustics," "sound," or "noise" herein are intended to include airborne vibrations in the ultrasonic or subsonic range.

[0165] Some implementations of the disclosed acoustic analysis techniques can implement cepstrum analysis. The cepstrum can be considered as the inverse Fourier transform of the logarithmic spectrum of the forward Fourier transform of the decibel spectrum, etc. This operation can basically convert the convolution of the impulse response function (IRF) and the sound source into an addition operation, making it easier to then consider or remove the sound source in order to separate the IRF data for analysis. The technique of cepstrum analysis is described in detail in "The Cepstrum: A Guide to Processing" (Childers et al., Proceedings of the IEEE, Vol. 65, No. 10, October 1977) and Randall RB, Frequency Analysis, Copenhagen: Bruel & Kjaer, p. 344 (1977, revised in 1987). The application of cepstrum analysis to respiratory therapy system component identification is described in detail in PCT Publication No. WO 2010 / 091462, entitled “Acoustic Detection for Respiratory Treatment Apparatus,” the entire contents of which are incorporated herein by reference.

[0166] Cepstrum analysis can be understood in terms of the properties of convolution. The convolution of f and g can be written as f*g. This operation can be considered the integral of the product of two functions (f and g) after a function inverse shift. Therefore, it is an integral transform, as follows:

[0167]

[0168] Although the symbol t is used above, it does not necessarily represent the time domain. However, in this context, the convolution formula can be described as a weighted average of the function f(τ) at time t, where the weights are given by a simple translation g(-τ) by t. As t changes, the weighting function emphasizes different parts of the input function.

[0169] A mathematical model capable of relating the output to the input of a time-invariant linear acoustic system (e.g., the pneumatic path of a respiratory therapy system) can be based on convolution. The sound signal generated by the microphone 4270 in the air circuit 4170 can be considered as the input sound signal "convolved" with the system impulse response function (IRF) as a function of time (t).

[0170] y(t)=s1(t)*h1(t) (2)

[0171] Where y(t) is the output sound signal generated by microphone 4270; s1(t) is the input sound signal, such as the sound generated in or by pressure generator 4140 of respiratory therapy device 4000, and h1(t) is the system IRF from the sound source to microphone 4270. The system IRF h1(t) can be thought of as the system response to a unit pulse input.

[0172] By converting Equation (2) to the frequency domain through Fourier transformation (e.g., discrete Fourier transform ("DFT") or fast Fourier transform ("FFT")) of the sound signal y(t) and considering the convolution theorem, the following equation is produced:

[0173] Y(f)=S1(f)H1(f) (3)

[0174] where Y(f) is the Fourier transform (spectrum) of y(t); S1(f) is the Fourier transform of s1(t); and H1(f) is the Fourier transform of h1(t). In other words, convolution in the time domain becomes multiplication in the frequency domain.

[0175] We can apply logarithm operation to equation (3) to convert the multiplication into addition:

[0176] Log{Y(f)}=Log{S1(f)}+Log{H1(f)} (4)

[0177] Equation (4) can then be converted back to the time domain by an inverse Fourier transform (IFT) (e.g. inverse DFT or inverse FFT), which results in the complex-valued "cepstrum" - the inverse Fourier transform of the log of the spectrum Y(f):

[0178]

[0179] The abscissa τ is a real-valued variable, called the cepstrum, measured in seconds. Thus, the convolution in the time domain becomes additive in the log of the spectrum, and so does in the cepstrum or inverse frequency domain. In particular, the output cepstrum is composed of two additive components: the cepstrum of the input signal s1(t) and the cepstrum of the system IRF h1(t)

[0180] Considering data from the cepstrum analysis, e.g. inspecting the data values in the cepstrum domain, can provide information about the RT system. For example, by comparing the cepstrum data of a system with a previous or known baseline of the cepstrum data of that system, the comparison (e.g. difference) can be used to identify differences or similarities in the system, which can then be used to implement automatic control for changing functionality or purpose.

[0181] 5.8.1 Component identification

[0182] As mentioned previously, a respiratory therapy system can typically comprise an RPT device, a humidifier, an air delivery conduit and a patient interface. Various different forms of patient interface can be used with a given RPT device, such as a nasal pillow, a nasal prong, a nasal mask, a nasal and oral (bipap) mask, or a full face mask. Furthermore, different forms of air delivery conduit can be used. Furthermore, even for a common form, such as a nasal mask, there can be differences in design specifications, such as size and / or shape, for different models (e.g. different nasal masks) of patient interface form. In order to improve control of therapy delivered to the patient interface, it can be advantageous to measure or estimate therapy parameters, such as pressure and vent flow in the patient interface. In a system using therapy pressure estimation, knowing the type of component used by the patient can improve the accuracy of the therapy pressure estimation, and hence the efficacy of the therapy. In order to obtain this knowledge, some RPT devices include a menu system that enables the patient to select the type of system component used, including the patient interface, such as the brand, form, model, etc. Once the patient inputs the type of component, the RPT device controller can select appropriate operating parameters for the RPT device that best coordinate with the selected component.

[0183] The present technology can improve known equipment to identify components of an RT system based on acoustic analysis, thereby facilitating coordination between the RPT device and peripheral components of the RT system. In this specification, "identification" of a component means identification of the type of that component in order to distinguish that component from other different (e.g., pneumatically different) component types that the RT system may use. Such identification can then allow access to data associated with the identification, such as pneumatic characteristics, which can then be applied by a controller of the RT device in its pneumatic control (e.g., therapy control). In the following, for the sake of brevity, "mask" is used synonymously with "patient interface", even though there is a patient interface that is not generally described as a "mask".

[0184] A first embodiment of the present technology includes an apparatus, device, and / or method for identifying components in a respiratory therapy system. The components may be masks and catheters. This embodiment can identify the length of catheter in use, as well as the mask connected to the catheter. The technology can identify the mask and catheter regardless of whether the patient is wearing a mask at the time of identification.

[0185] The present technology may enable analysis of sound signals generated by the microphone 4270 positioned as described above.

[0186] The present technology includes an analysis method that is able to separate acoustic mask reflections from other system noises and responses (including but not limited to blower sounds). This makes it possible to identify differences between the acoustic reflections of different masks (typically determined by mask shape, construction, and materials) and can allow different masks to be identified, for example without requiring user or patient intervention.

[0187] An exemplary method of identifying a mask is to sample the output sound signal y(t) generated by microphone 4270 at a desired sampling rate (e.g., at least the Nyquist rate, e.g., 20 kHz). The cepstrum can be calculated from the sampled output signal The reflected component of the cepstral spectrum can then be separated from the input signal component of the cepstral spectrum. The reflected component of the cepstral spectrum includes the acoustic reflections of the mask from the input sound signal and is therefore referred to as the "acoustic signature" or "mask signature" of the mask. The acoustic signature can then be compared to a predefined or predetermined database (e.g., any suitable type of data storage structure) of previously measured acoustic signatures obtained from a system containing known masks. Optionally, some criteria can be set to determine appropriate similarity. In an exemplary embodiment, the comparison can be done based on a single maximum data peak in the cross-correlation between the measured and stored acoustic signatures. However, the method can be improved by comparing over several data peaks, or alternatively, where the comparison is done over a set of extracted unique cepstral features.

[0188] Alternatively, the same method can also be used to determine the length of the conduit by finding the delay between the sound received from the RPT device and its reception of the reflection from the mask; the delay can be proportional to the length of the tube. Additionally, changes in the diameter of the tubing can increase or decrease the amplitude of the reflected signal and can therefore also be identifiable. This assessment can be made by comparing the current reflection data to previous reflection data. The change in diameter can be considered to be a certain proportion of the change in amplitude from the reflected signal (i.e. the reflection data).

[0189] Figure 7 is a schematic diagram of an RT system 7000 in accordance with one aspect of the technology. In this example embodiment, as shown in Figure 7 the conduit 7010 (length L) effectively acts as a waveguide for the sound produced by the RPT device 7040, for example including the sound from the loudspeaker, or alternatively, just the operating noise of the blower (e.g. the motor and / or impeller). In this example embodiment, the input signal is the sound emitted by the RPT device 7040 (i.e. without the sound from the loudspeaker). The input signal (e.g. a pulse) enters the microphone 7050 located at one end of the conduit 7010, travels along the air path in the conduit 7010 to the mask 7020, and is reflected back along the conduit 7010 by the features in the air path (including the conduit and the mask) to enter the microphone 7050 again. Thus, the system IRF (the output signal produced by the input pulse) contains an input signal component and a reflection component. The key feature of the RT system 7000 is the time it takes for the sound to travel from one end of the air path to the opposite end. This interval is manifested in the system IRF because the microphone 7050 receives the input signal from the RPT device 7040 and then receives the input signal filtered by the conduit 7010 and reflected and filtered by the mask 7020 (and any other system 7030 connected to the mask, for example the human respiratory system when the mask 7020 is placed on a patient) some time later. This means that the component of the system IRF associated with the reflection from the mask end of the conduit 7010 (the reflection component) is delayed relative to the component of the system IRF associated with the input signal (the input signal component), which arrives at the microphone 7050 after a relatively short delay. (In practice, this short delay can be neglected and the zero time approximated to the time at which the microphone 7050 first responds to the input signal.) This delay is equal to 2L / c (where L is the length of the conduit and c is the speed of sound in the conduit).

[0190] Another feature of the system 7000 is that, due to the losses easily incurred by the air path, if the conduit is long enough, the input signal component of the system IRF will have decayed to a negligible amount by the time the reflection component of the system IRF begins. If this is the case, the input signal component can be separated from the reflection component of the system IRF. As an example, Figure 8An example of one such system IRF from an exemplary treatment system is shown, where the input signal may originate from the RPT device's blower 4142. Alternatively, the input signal may include sound originating from a speaker at the device end of the air path (with or without sound generated by the RPT device 7040). Figure 8 It is shown that the reflected component 8020 of the system IRF is delayed relative to the input signal component 8010 in the system IRF, and the delay is equal to 2L / c.

[0191] The cepstrum of the system IRF associated with equations (2), (4) and (5) described previously is It usually has the same characteristics as the system IRF h1(t). That is, the inverse spectrum The cepstrum analysis includes the reflection component concentrated around the cepstrum of 2L / c and the input signal component concentrated around the cepstrum of 0. In the present technology, the cepstrum analysis is configured to convert the output cepstrum into the input signal by, for example, checking the position and amplitude of the output cepstrum data. The reflected components and other system artifacts (including but not limited to input signal components ) separation.

[0192] If the input signal s1(t) is transient (e.g., an impulse) or stationary random, this means that the input signal component of the cepstrum is This separation can be achieved by focusing the input signal around the cepstrum 0. For example, the input signal could be a sound produced by an RPT device running at a constant speed during the time period measured by the microphone. This sound can be described as "cyclostationary". That is, it is stationary and random and statistically periodic. This means that the input signal component and the reflected component of the system IRF can be "smeared out" over all measurement times of the output signal y(t) because at any point in time the output signal y(t) is a function of all previous values ​​of the input signal and the system IRF (see equation (2)). However, the cepstrum analysis described above can be implemented to convert the output cepstrum The reflected component of is separated from this convolution mixture.

[0193] Figure 9 Describes the Figure 7 7050 ).

[0194] exist Figure 9In Figure 1, the reflected component can be clearly seen in all six cepstra, starting at a frequency of approximately 12 milliseconds (12ms). This location is the same as expected (2L / c) because in the exemplary treatment system, a two-meter catheter was used and the speed of sound was 343m / s. Figure 9 , the graph shows the cepstrum from the mask in the following order from top to bottom:

[0195] -ResMed Ultra Mirage TM , 10krpm;

[0196] -ResMed Ultra Mirage TM , 15krpm;

[0197] -ResMed Mirage Quattro TM , 10krpm;

[0198] -ResMed Mirage Quattro TM , 15krpm;

[0199] -ResMed Swift II TM , 10krpm; and

[0200] -ResMed Swift II TM , 15krpm

[0201] By increasing the catheter length, the arrival delay of the reflection from the mask can also be significantly increased. Figure 9 When compared, the increase in delay is based on the above calculations which yield an approximate value for the catheter length.

[0202] According to the present technology, data related to the reflection component, e.g. Figure 9 The data shown collectively in the cepstrum of the image can then be compared with similar data from a set of previously identified mask reflection components or a set of predetermined acoustic signatures, such as data contained in a memory or database of mask reflection components. Such a set can contain data from one or more such previously identified mask reflection components.

[0203] For example, the reflected component of the mask being tested (the "mask signature") can be separated from the inverse spectrum of the output signal generated by the microphone. This mask signature can be compared with previous or predetermined mask signatures of known masks stored as data templates of the device in order to confirm the identification of the known mask. One way of doing this is to calculate the cross-correlation between the mask signature of the mask being tested and the mask signatures of all previously stored known masks or data templates. The probability that the cross-correlation with the highest peak corresponds to the mask being tested is high, and the position of the peak should be proportional to the length of the catheter.

[0204] However, more relevant points can also increase the accuracy of the identification step of the present technology. Therefore, additional data points can be utilized. Optionally, a least squares algorithm with test data and a known data set can be implemented in component identification. In addition, in some embodiments, additional feature extraction and recognition techniques can be utilized, which can be based on artificial intelligence / machine learning structures and strategies, such as neural networks or support vector machines. Other information sources can also be included as input to such structures and strategies to improve the accuracy of component identification. Examples are patient characteristics, treatment data, historical information (e.g., previously identified components), geographic location, and associated market data (e.g., sales figures for various components).

[0205] One complicating factor in acoustic component identification is acoustic "back reflections" from the device end of the conduit 7010. These back reflections occur from the device end of the conduit 7010 after sound reflected from the mask 7020 propagates backward along the conduit 7010, due to variations in acoustic impedance between the conduit 7010 and the internal cavity of the RPT device / humidifier 7040 to which it is connected. Such back reflections can have a blurring effect on the acoustic signature of the mask. For example, if the physical dimensions of the component being identified are similar to the distance between the microphone 7050 and any discontinuities in the cross-section of the RPT device / humidifier 7040, then reflections from the component may be superimposed on the output signal corresponding to the back reflections.

[0206] Figure 10 A graph illustrating this effect is included. Trace 1050 is the output cepstrum, which contains clear peaks 1060 at frequencies associated with sound propagating from the microphone to the component to be identified and reflected from the component back to the microphone. Cepstrum trace 1050 also contains clear troughs 1070 at frequencies commonly associated with (a) sound propagating from the microphone to the component, (b) reflections from the component back down the duct to the blower device end of the duct, and (c) back reflections from the blower device end to the microphone.

[0207] In some cases, component identification can be made more precise by characterizing backreflections and deconvolving them from the reflected components. Alternatively, component identification can be made more precise if backreflections can be reduced or minimized by design. The latter case is complicated by the need to maintain an open channel from the blower end to the patient interface so that treatment pressure can be delivered into the waveguide formed by the treatment catheter.

[0208] In one such implementation 1105, Figure 11As shown, the end of the conduit 1110 closest to the microphone 1150 and away from the patient's respiratory airway 1130 includes a sound absorbing structure 1160, which is configured to reduce back reflections. The structure of such a sound absorbing structure can be generally open, so that it has a channel that allows airflow (for treatment) and sound to pass through, and can therefore be considered a through (acoustic) sound absorbing conduit. Such a through sound absorbing conduit can be a transition conduit channel, the inner surface of which defines the cross-section of the channel through the structure, wherein the cross-section expands, for example, in a linear manner along the acoustic or airflow path of the conduit channel due to the contour of the inner surface. As shown, the structure 1160 can be located along the conduit between the microphone and the blower, so that the microphone is located along the conduit between the structure and the patient interface. Figure 11 An example of structure 1160 is shown as a horn extending from the device end of the catheter 1110 into the internal cavity of the RPT device / humidifier 1140, the diameter of the horn at the device end of the catheter 1110 can be the same as the diameter of the catheter 1110 and have a gradually increasing cross-sectional or transverse dimension (e.g., diameter), such as in a direction away from the component to be identified. In this regard, the cross-section of the structure 1160 expands as the cross-section moves further away from the patient interface end of the patient circuit due to its inner surface profile. Because the acoustic impedance of an acoustic waveguide is related to the internal transverse dimension (e.g., diameter) of the waveguide, unlike an absorptive material, the horn structure 1160 minimizes back reflections by gradually varying the acoustic impedance between the catheter 1110 and the cavity of the RPT device / humidifier 1140. The horn structure 1160 can have a shape such as Figure 11 and 11A The conical profile shown, or the profile of the horn can be changed to something like Figure 11B The structure 1160 is curved in the manner of the bell of a brass instrument in the example of FIG. The structure 1160 serves to reduce the back reflection component in the acoustic signature of the system component 1120, thereby increasing the identifiability of the system component.

[0209] The cepstrum can be calculated over a finite time window of the sampled output signal y(t). A longer window can produce a clearer separation between the acoustic signature and the input signal components. However, due to factors such as changes in pressure and / or flow and / or humidity during the respiratory cycle, the acoustic properties of the air path may change over time. For example, if the evaluation is being performed while the patient is in use, the window should not be made too long so that the air path properties do not change significantly during the window. In one example, the window duration is 200 ms.

[0210] When performing the IFT in equation (5) to calculate the cepstrum Previously, subtracting a low-pass filtered version of the log spectrum Log{Y(f)} from the log spectrum Log{Y(f)} itself, for example by subtracting a moving average of the log spectrum Log{Y(f)} from the log spectrum Log{Y(f)}, could flatten the overall shape of the log spectrum and reduce the sensitivity of the acoustic signature separation to the randomness of the input signal s1(t). That is, even if the input signal s1(t) is not particularly random, this flattening would still reduce the randomness of the input signal components. The output cepstrum is concentrated near the origin (τ=0) For a given input signal, the output cepstrum is added to the The input signal components of the system IRF (acoustic wave signature) in Separability from the reflected components. The filter needs to be set carefully so that the duct resonance frequencies are not removed during the flattening process. For example, the filter cutoff point should be low enough (or the moving average window long enough) so that the duct resonances are significantly eliminated by the filter and thus retained by the flattening process. In an alternative implementation, the logarithmic spectrum Log{Y(f)} can be high-pass filtered before performing the IFT in equation (5) to calculate the cepstrum

[0211] Multiple output cepstra can be calculated over multiple windows The acoustic signatures extracted from the individual cepstra can be combined together into a single combined acoustic signature before being compared with previously measured acoustic signatures (e.g., template data). In some implementations, the combination is an averaging of multiple acoustic signatures. This combination tends to reduce the effects of noise on the combined acoustic signature.

[0212] To minimize the impact of respiratory cycle variations on airway acoustic properties, and therefore minimize variations in the acoustic signature between windows, the windows can be timed to coincide with (synchronize with) specific points in the respiratory cycle, such as the peak of inspiratory flow or the pause at the end of expiration. In a similar manner, the windows can be synchronized with specific shaft rotation speeds of the RT device to reduce or highlight the effects of rotating machinery on the signature. In some embodiments, the acoustic analysis can include diagnosis or prognosis of machinery conditions (e.g., bearing failure).

[0213] Even in this "breath synchronization" implementation, other sources of variability in the air path between windows can affect the relative delay of each acoustic signature in the cepstral time domain. Depending on how the acoustic signatures are combined, this can cause the combined acoustic signature to be smeared or blurred, affecting its distinctiveness.

[0214] Therefore, in some implementations, a combining method can be selected that is robust to small variations in the delays (relative offsets along the quasi-frequency axis) between multiple acoustic signatures. In one such implementation, newly calculated acoustic signatures are incorporated into the combined acoustic signature one by one so that the combined acoustic signature is progressively constructed from each newly calculated acoustic signature. To achieve the merging, each newly calculated acoustic signature can be compared with the combined acoustic signature to estimate its delay relative to the combined acoustic signature. Before incorporating the newly calculated acoustic signature into the combined acoustic signature, the estimated relative delay can be compensated by shifting the acoustic signature by its estimated delay. In one such implementation, the delay can be estimated by finding the location of a prominent feature in the acoustic signature, such as its largest negative peak. In an alternative implementation, the delay can be estimated by correlating the acoustic signature with the combined acoustic signature and locating the correlation peak. Delay estimation and compensation of the acoustic signatures can be referred to as alignment of the acoustic signatures. In the case of combining by averaging, each shifted acoustic signature may be averaged with the combined waveform.

[0215] Other combining techniques can produce a combined acoustic signature that is robust to small variations in delay, such as combining based on wavelet transforms.

[0216] Figure 12 is a flow chart illustrating a method 1200 for identifying components of an air path of a respiratory therapy system according to one aspect of the present technology. The method 1200 may begin at step 1210 by computing an output cepstrum from an output signal y(t). For example during the respiratory synchronization window as described above with respect to equation (5). Optionally, before calculating the output cepstrum as described above Step 1210 flattens the logarithmic spectrum Log{Y(f)}.

[0217] Next is step 1220, in which the reflection component (acoustic signature) is separated from the cepstral spectrum calculated in step 1210. In the next step 1230, the acoustic signature is merged into a combined acoustic signature in a manner that is robust to small shifts in the cepstral domain, as described above. (On the first iteration, step 1230 simply designates the acoustic signature as the combined acoustic signature.)

[0218] Then, step 1240 checks whether enough acoustic signatures have been combined to form a combined acoustic signature. If not ("No"), method 11000 proceeds to step 1260, which waits for the next respiratory synchronization window before returning to step 1210 to calculate a new cepstrum. If so ("Yes"), step 1250 compares the combined acoustic signature with a predefined or predetermined waveform data set to identify the current component, such as a database of previously measured acoustic signatures obtained from a system containing known components. Then, method 1200 ends.

[0219] Figure 13 Two graphs are included. Top graph 1300 includes a collection of acoustic signatures without alignment as the tube length varies between windows. Bottom graph 1350 includes a collection of the same acoustic signatures after alignment, as achieved based on the maximum negative peak described above. As can be seen, the collection of acoustic signatures produced after alignment produces a more clearly defined combined acoustic signature than the collection of acoustic signatures without alignment.

[0220] about Figure 12 The signal processing analysis described can be implemented by a controller or processor, for example using firmware, hardware, and / or software as previously described. Such a controller can identify the mask and catheter. This identification information or data related to the identity of the patient interface can then be relayed to another controller, processor, system, or computer, or used by the controller. This information can then be used to adjust therapy or other settings used to control the RPT device in the delivery of respiratory therapy by the respiratory therapy system.

[0221] For example, the above-described technology may be implemented as part of a controller for a respiratory therapy system, such as a CPAP device. Such an implementation may help reduce the need for a user of the CPAP device or a clinician to manually enter or adjust the device's settings for a particular mask. Thus, some embodiments of the present technology may even allow a user to change masks without requiring user input or setup of the CPAP device, as such a system may automatically setup the device with the settings adjusted based on the automatically identified patient interface or mask configuration. In some cases, it may simplify setup by prompting the user with the identification from the above-described automatic process so that the user can simply enter confirmation of the identification, thereby avoiding or reducing the need for the user to scroll through many possible patient interface entries on the user interface of the RT device to make the setup.

[0222] Additionally, in some embodiments, information related to the identity of a particular mask can be selectively transmitted to the manufacturer, physician, or clinician so that the information can be used to assist the patient with troubleshooting. TMand / or WiFi TM wireless communication protocols to send this data.

[0223] Additionally, in some embodiments, information related to the identity of a particular mask can be used to trigger an action, such as manually or automatically deploying personalized coaching or training content relevant to the particular mask, such as a guide to adjusting the mask. Such material can be delivered to the user via the therapy device screen or a supported mobile device application, or other communication means such as email or SMS messages.

[0224] Alternatively, in some embodiments of the present technology, the controller can be configured to detect whether the patient is currently wearing the mask based on the properties of the acoustic reflection, for example by comparing the test cepstral data with template cepstral data recorded during patient use. Similarly, the present technology can be implemented to determine whether there are technical problems with the mask, including leaks and / or kinks in the system. This can also be detected by comparing the current test cepstral data with cepstral data recorded when the mask was in good working order and properly seated on the patient's face (e.g., without leaks).

[0225] In some embodiments, blower speeds greater than those described above may be achieved during component identification. For example, some ducts use materials with properties that reduce noise. In such systems, the acoustic loss of the system may fluctuate. If an increase in loss (e.g., a decrease in amplitude) is detected by the measurement signal, the decibel level of the sound or noise source may be increased to overcome the effects of the acoustic loss. This can be achieved by increasing the speed of the blower during the test measurement. In addition, other elements included in the air path may increase acoustic losses. These elements may include: humidifiers, noise baffles, and valves. Similarly, losses that may be caused by these components may also be overcome by increasing the noise source level or amplitude. Typically, a suitable sound level for the input signal may be approximately 20 dBa or greater.

[0226] The frequency range of microphone 4270 can be selected based on the geometric resolution required for component identification. Resolving information about small dimensions generally requires high frequency content in the generated sound signal. A typical air circuit used for respiratory therapy may exhibit tube resonances with a fundamental frequency of less than 100 Hz, but higher harmonics appear in the spectrum at integer multiples of the fundamental frequency, up to and including 10 kHz. The frequency range of microphone 4270 can be selected to be large enough to allow sensing of enough resonant harmonics so that periods associated with the harmonic spacing are present in the inverse Fourier transform of the logarithmic spectrum. Therefore, in one implementation, microphone 4270 has an upper frequency limit of at least 10 kHz.

[0227] As previously mentioned, some embodiments can utilize a sound source such as a speaker to generate sound pulses or white noise. This is particularly useful for respiratory therapy systems that have very quiet blowers that do not generate a lot of noise. For example, when using ResMed at speeds typically less than 6krpm TM When an RPT device is used, the blower is very quiet. In this case, using only the sound of the blower as a sound source to generate an input signal may not be sufficient to identify certain components. This can be overcome by including an additional sound source in the air path. This can be activated during the measured time period, such as when the mask is initially attached to the catheter. Although the additional sound source can be a speaker, other sound emitters can also be used. For example, a simple acoustic generator can be configured to vibrate in response to the air flow from the RPT device, such as a reed that can be selectively activated and paused (e.g., mechanically applied to and removed from the system's air path). This can be used to selectively generate sound pulses. Alternatively, the actuating valve of the RPT device can be used as an additional sound source.

[0228] Additionally, a sound source, such as a speaker, can be used to fill in gaps in the sound spectrum produced by the blower. For example, the speaker can be used to generate a signal designed to have a specific frequency spectrum, such that the addition of the blower noise and the speaker sound creates a white spectrum. This can improve the system's detection accuracy and enhance the perceived quality of the sound experienced by the user of the treatment device.

[0229] In some embodiments, the masks can be designed to have unique acoustic response characteristics. For example, unique acoustic resonators or unique characteristic dimensions can be designed into the mask or conduit to allow for easier differentiation of the acoustic reflection data from each mask.

[0230] In some embodiments, autocorrelation (ie, inverse Fourier transform of the power spectrum) may be implemented instead of cepstrum analysis.

[0231] In other embodiments of the present technology, in addition to identifying the type, acoustic reflections can also be analyzed to identify specific characteristics of the mask. For example, system response data can be used to identify characteristics of the mask and catheter. Characteristics may include: diameter, construction material, air cavity volume, overall mask and catheter construction, etc.

[0232] 5.9 Glossary

[0233] For purposes of this technical disclosure, in some forms of the technology, one or more of the following definitions may apply. In other forms of the technology, alternative definitions may apply.

[0234] 5.9.1 Overview

[0235] Air: In some forms of the present technology, air may be considered to refer to atmospheric air, and in other forms of the present technology, air may be considered to refer to some other combination of breathable gases, such as atmospheric air enriched with oxygen.

[0236] Environment: In certain forms of the present technology, the term environment can have the meaning of (i) external to a respiratory therapy system or patient, and (ii) immediately surrounding a respiratory therapy system or patient.

[0237] For example, the ambient humidity relative to the humidifier can be the humidity of the air directly surrounding the humidifier, such as the humidity inside the room that the patient is sleeping in. This ambient humidity can be different from the humidity outside the room that the patient is sleeping in.

[0238] Automatic Positive Airway Pressure (APAP) Therapy: CPAP therapy in which the therapy pressure is automatically adjusted between a minimum and a maximum limit, eg, varying with each breath, depending on whether there is an indication of an SBD event.

[0239] Continuous Positive Airway Pressure (CPAP) therapy: A respiratory pressure therapy in which the therapy pressure can be approximately constant throughout the patient's breathing cycle. In some forms, the pressure at the airway entrance will be slightly higher during exhalation and slightly lower during inspiration. In some forms, the pressure will vary between different breathing cycles of the patient, for example, increasing in response to detecting an indication of partial upper airway obstruction and decreasing in the absence of an indication of partial upper airway obstruction.

[0240] Flow rate: The volume (or mass) of air delivered per unit time. Flow rate can refer to an instantaneous quantity. In some cases, references to flow rate will be to a scalar quantity, i.e., a quantity having only magnitude. In other cases, references to flow rate will be to a vector quantity, i.e., a quantity having both magnitude and direction. Flow rate can be given by the symbol Q. 'Flow rate' is sometimes simply abbreviated to 'flow' or 'air flow'.

[0241] Leakage: The word leakage is to be considered as undesirable air flow. In one example, a leak may occur due to an incomplete seal between the mask and the patient's face. In another example, a leak may occur in the swivel elbow to the surrounding environment.

[0242] Patient: A person, whether or not they have a respiratory condition.

[0243] Pressure: force per unit area. Pressure can be expressed in a range of units, including cmH2O, gf / cm 2 , hectopascal. 1cmH2O equals 1g-f / cm 2 And is about 0.98 hectopascal.In this specification, unless otherwise specified, pressure is given in cmH2O.

[0244] Respiratory Pressure Therapy (RPT): The application of a supply of air to the airway entrance at a therapeutic pressure that is typically positive relative to atmosphere.

[0245] Seal: can be a noun referring to a structure (seal) or a verb referring to that effect (seal). Two elements can be constructed and / or arranged to 'seal' or achieve a 'seal' between them without the need for a separate 'seal' element itself.

[0246] 5.9.2 Patient Interface

[0247] Plenum: A mask plenum will be taken to mean a portion of the patient interface having walls at least partially enclosing a volume of space which, in use, has air pressurized therein to above atmospheric pressure. The housing may form part of a wall of the mask plenum.

[0248] Shell: Shell will be understood to mean a curved, relatively thin structure with bendable, stretchable, and compressible stiffness. For example, the curved structural wall of a mask may be the shell. In some forms, the shell may be multi-faceted. In some forms, the shell may be airtight. In some forms, the shell may not be airtight.

[0249] Vent: (noun): A structure that allows air flow from the interior of a mask or tube to the ambient air for clinically effective clearance of exhaled gases. For example, clinically effective clearance may involve a flow rate of about 10 liters per minute to about 100 liters per minute, depending on the mask design and the treatment pressure.

[0250] 5.10 Other Notes

[0251] 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 facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent Office file or records, but otherwise reserves all copyright rights whatsoever.

[0252] Unless the context clearly indicates otherwise and a numerical range is provided, it is understood that each intervening value between the upper and lower limits of that range, to the tenth of the unit of the lower limit, and any other stated or intervening value in that stated range, is broadly encompassed within the present technology. The upper and lower limits of these intermediate ranges may independently be included in the intermediate ranges and are also encompassed within the present technology, subject to any specifically excluded limit in the stated range. Where the range includes one or both of the limits, ranges excluding either or both of those included limits are also encompassed within the present technology.

[0253] Furthermore, where a value or values ​​are described herein for implementation as part of the present technology, it should be understood that such values ​​may be approximate unless otherwise indicated, and that such values ​​may be used to any appropriate number of significant digits to the extent permitted or required by practical technical implementation.

[0254] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention, a limited number of exemplary methods and materials are described herein.

[0255] When a particular material is identified as being used to construct a component, obvious alternative materials having similar properties may be used as substitutes. Furthermore, unless otherwise specified, any and all components described herein are understood to be capable of being manufactured and thus may be manufactured together or separately.

[0256] It must be noted that, as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural equivalents unless the context clearly dictates otherwise.

[0257] As used herein, the term "about" refers to an amount that varies by up to 30%, preferably up to 20%, and more preferably up to 10% relative to a reference amount. The use of the word "about" to qualify a number is simply a clear indication that the number should not be interpreted as an exact value.

[0258] All publications mentioned herein are incorporated herein by reference in their entirety, to disclose and describe the method and / or material as the subject of those publications. Providing the publication discussed herein is only for the disclosure before the date of submission of the present application. Anything herein should not be construed as admitting that the technology is not entitled to the priority of these publications due to prior art. In addition, the publication date provided may be different from the actual publication date, and it may need to be confirmed separately.

[0259] The terms "comprises" and "comprising" should be understood to refer to each element, component or step in a non-exclusive manner, indicating that the marked elements, components or steps may be present or utilized, or in combination with other elements, components or steps that are not marked. Therefore, throughout this specification, unless the context requires otherwise, the words "comprise", "comprises" and "comprising" will be understood to imply the inclusion of the stated step or element or group of steps or elements, but not the exclusion of any other step or element or group of steps or elements. Any of the following terms: "including" or "which includes" or "that includes" as used herein are also open terms, which also mean to include at least the elements / features following the term, but not to exclude other elements / features. Therefore, "comprising" is synonymous with "comprising" and means "including".

[0260] The various methods or processes outlined herein may be encoded as software that can be executed on one or more processors using any of a variety of operating systems or platforms. In addition, such software may be written using any of a variety of suitable programming languages ​​and / or programming or scripting tools, and may also be compiled into executable machine language code or intermediate code that is executed on a framework or virtual machine.

[0261] In this regard, various inventive concepts may be embodied as a processor-readable medium or computer-readable storage medium (or multiple such storage media) (e.g., computer memory, one or more floppy disks, compact disks, optical disks, magnetic tape, flash memory, circuit configurations in field programmable gate arrays or other semiconductor devices, or other non-transitory media or tangible computer storage media) encoded with one or more programs or processor control instructions that, when executed on one or more computers or other processors, perform methods that implement various embodiments of the technology described above. The one or more computer-readable media may be transportable so that the one or more programs stored thereon can be loaded onto one or more different computers or other processors to implement various aspects of the technology as described above.

[0262] The terms "program" or "software" are used herein in a general sense to refer to any type of computer code or set of computer-executable instructions that can be used to program a computer or other processor to implement various aspects of the embodiments discussed above. Furthermore, it should be understood that, according to one aspect, one or more computer programs that, when executed, perform the methods of the present technology need not reside on a single computer or processor, but can be distributed in a modular manner across multiple different computers or processors to implement various aspects of the present technology. For example, some versions of the present technology may include a server that can access any computer-readable or processor-readable medium described herein. The server can be configured to receive a request to download processor-control instructions or processor-executable instructions from the medium to an electronic device, such as a smartphone or smart speaker, via a network, such as a communications network, the internet, or the Internet. Thus, the electronic device can also include a medium that executes the instructions from the medium. Similarly, the present technology can be implemented as a method for a server accessing any of the media described herein. The method can include receiving a request at a server to download processor-executable instructions from the medium to an electronic device via a network; and, in response to the request, sending the instructions from the medium to the electronic device. Alternatively, the server can access the medium to execute the instructions from the medium.

[0263] Computer-executable instructions can be in various forms, such as program modules, that are executed by one or more computers or other devices. Generally speaking, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. In general, the functionality of program modules can be combined or distributed as needed in various embodiments.

[0264] Furthermore, the data structure can be stored in a computer-readable medium in any suitable form. To simplify the description, the data structure can be shown as having fields that are related by position in the data structure. This relationship can also be achieved by assigning memory in the computer-readable medium to the fields with locations that convey the relationship between the fields. However, any suitable mechanism can be used to establish the relationship between the information in the fields of the data structure, including through the use of pointers, tags, or other mechanisms that establish relationships between data elements.

[0265] Although the present technology has been described herein with reference to specific examples, it should be understood that these examples are merely illustrative of the principles and applications of the present technology. For example, although an acoustic generator and acoustic monitoring technology are described herein in specific examples of the use and components of an RPT device, it should be understood that such an acoustic generator and acoustic monitoring technology can be implemented similarly to components of any respiratory therapy (RT) device, such as a high flow therapy (HFT) device that provides a controlled airflow at a therapeutic flow level through a patient interface. Thus, an HFT device is similar to a pressure-controlled RPT device, but is configured with a controller suitable for flow control. In such an example, the acoustic generator can be configured to measure gas characteristics associated with the high flow therapy produced by the HFT device and can be integrated to sample the airflow of the patient circuit of the HFT device, its catheter connector and / or patient interface. Thus, the HFT device can optionally include an acoustic receiver, and the processing techniques for acoustic analysis described herein, for receiving the acoustic / sound signals generated by the acoustic generator implementing the HFT device.

[0266] In some cases, terms and symbols may imply specific details that are not required for practicing the present technology. For example, although the terms "first" and "second" may be used, unless otherwise indicated, they are not intended to represent an arbitrary order, but rather may be used to distinguish between different elements. Furthermore, although the process steps in the method may be described or illustrated in a certain order, this order is not required. Those skilled in the art will recognize that this order may be modified, and / or aspects of the order may be performed simultaneously or even synchronously.

[0267] It is therefore to be understood that numerous modifications may be made to the illustrative examples, and that other arrangements may be devised without departing from the spirit and scope of the present technology.

[0268] 5.11 Reference Symbols

[0269]

[0270]

[0271]

Claims

1. An apparatus for producing respiratory therapy, the apparatus comprising: a pressure generator configured to generate a pressurized air supply along a pneumatic path of the device including an outlet, wherein the pressurized air supply is generated from the outlet along an air circuit to a patient interface; a sensor configured to generate an acoustic signal representative of the sound of the pressure generator in the air circuit; a sound absorbing structure configured to reduce reflection of sound from the pressure generator along the air circuit, wherein the sound absorbing structure is trumpet-shaped and has a cross-section that gradually increases on a side away from the sensor, wherein the sound absorbing structure is arranged in the pneumatic path of the device, and wherein the sound absorbing structure is located between the pressure generator and the sensor; and A controller, wherein the controller is configured as: The acoustic signal is processed to identify the patient interface and / or the air circuit.

2. The device according to claim 1, wherein The sound absorbing structure is formed by a through-going sound absorbing duct configured to change the acoustic impedance between the air circuit and the cavity of the housing of the pressure generator.

3. The device according to claim 2, wherein The sound absorbing structure defines a cross-section of a passage through the through-going sound absorbing duct such that the cross-section expands along the path of the passage due to the contour of the inner surface of the through-going sound absorbing duct.

4. The device according to claim 3, wherein The cross section gradually expands as the cross section moves further away from the patient interface end of the air circuit.

5. The device according to any one of claims 1 to 4, wherein The device comprises a waveguide formed by at least the outlet and the air loop, and wherein the sound absorbing structure is located along the waveguide between the sensor and the outlet, and wherein the sensor is located along the waveguide between the sound absorbing structure and the air loop.

6. The device according to claim 1, wherein The horn has a conical profile.

Images