Characterization system for respiratory therapy

Abstract

Apparatus and methods that provide characterization of a system, such as the operation of a respiratory therapy device. Pressure and flow signals from a therapy session, such as where the system includes a patient interface having a delivery conduit and a vent, can be analyzed to determine a curve representative of the pressure and flow characteristics of the system. A pressure drop parameter can be derived to characterize the pressure drop from a sensor in the therapy generator to the patient interface, the parameter being based on a first function that characterizes the curve and a second function that characterizes a curve representative of the pressure and flow characteristics of a component of the system. A parameter can be derived from a difference between the first and second functions. A signal(s) can be generated to control the therapy generator to adjust attributes of the delivered airflow based on the pressure drop parameter.

Description

[Background technology]

[0001] 1 CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 249,864, filed September 29, 2021, the entire disclosure of which is incorporated herein by reference. [Technical field]

[0002] 2 Background technology 2.1 Technical Field The present technology relates to one or more of screening, diagnosis, monitoring, treatment, prevention, and amelioration of respiratory related disorders. The present technology also relates to medical devices or apparatus and their uses.

[0003] 2.2 Description of Related Art 2.2.1 The human respiratory system and its disorders The body's respiratory system facilitates gas exchange. The nose and mouth form the entrance to a patient's airways.

[0004] The airways have a series of branching tubes that become narrower, shorter and more numerous as they reach deeper into the lungs. The primary function of the lungs is gas exchange, allowing oxygen to move from inspired air to venous blood and carbon dioxide to move in the opposite direction. The trachea divides into the left and right main bronchi, which further divide eventually into the terminal bronchioles. The bronchi constitute the conducting airways and do not participate in gas exchange. Further division of the airways leads to the respiratory bronchioles and ultimately to the alveoli. The alveolar region of the lungs is where gas exchange takes place and is called the respiratory zone. Refer to Respiratory Physiology, 9th Edition, by John B. West, Lippincott Williams & Wilkins, 2012.

[0005] A variety of respiratory disorders exist, and particular disorders may be characterized by particular events, e.g., apnea, hypopnea, hyperpnea.

[0006] Examples of respiratory diseases include obstructive sleep apnea (OSA), Cheyne-Stokes respiration (CSR), respiratory failure, obesity hyperventilation syndrome (OHS), chronic obstructive pulmonary disease (COPD), neuromuscular diseases (NMD) and chest wall disorders.

[0007] Obstructive sleep apnea (OSA), a type of sleep-disordered breathing (SDB), is characterized by phenomena such as the occlusion or obstruction of the upper airway during sleep. It is caused by a combination of an abnormally small upper airway and a decrease in normal muscle tone in the area of ​​the tongue, soft palate, and posterior oropharynx wall during sleep. In this case, affected patients are forced to stop breathing for periods of time, usually 30 to 120 seconds, and sometimes 200 to 300 times each night. It often causes excessive daytime sleepiness, which can lead to cardiovascular disease and brain disorders. The syndrome is a common disorder, especially in middle-aged, overweight men, although the affected person may not be aware of the problem. See U.S. Patent No. 4,944,310 (Sullivan).

[0008] Cheyne-Stokes respiration (CSR) is another form of sleep-disordered breathing. CSR is a disorder of the patient's respiratory control system that results in rhythmic alternating increases and decreases in ventilation, known as CSR cycles. CSR is characterized by repeated deoxygenation and reoxygenation of arterial blood. By causing repeated oxygen deprivation, CSR can be harmful. In some patients, CSR is associated with repeated awakenings from sleep that cause severe insomnia, increased sympathetic activity, and increased afterload. See U.S. Patent No. 6,532, 959 (Berthon-Jones).

[0009] A range of therapies have been used to treat or ameliorate this condition, and healthy individuals can use them to prevent the onset of respiratory disease, but they have several drawbacks.

[0010] 2.2.2 Therapy A variety of respiratory therapies, such as continuous positive airway pressure (CPAP) therapy, non-invasive ventilation (NIV) and invasive ventilation (IV), are used to treat one or more of the above respiratory disorders.

[0011] 2.2.2.1 Respiratory pressure therapy Respiratory pressure therapy involves the delivery of air to the entrance of the airway at a controlled target pressure that is nominally positive relative to atmosphere throughout the patient's respiratory cycle (as opposed to negative pressure therapies such as tank ventilators or cuirasses).

[0012] Continuous positive airway pressure (CPAP) therapy is used to treat obstructive sleep apnea (OSA). Its mechanism of action is that the continuous positive airway pressure acts as a pneumatic splint, pushing the soft palate and tongue forward and away from the posterior oropharyngeal wall, thus preventing upper airway obstruction. Because treatment of OSA with CPAP therapy may be voluntary, patients may choose not to comply with the therapy if they find one or more of the devices used to deliver this therapy to be uncomfortable, difficult to use, expensive, or unattractive.

[0013] Noninvasive ventilation (NIV) provides ventilatory support to a patient through the upper airway to help the patient breathe and / or maintain sufficient oxygen levels in the body by completing some or all of the work of breathing. Ventilatory support is provided through a noninvasive patient interface. NIV is used to treat respiratory failures such as CSR and OHS, chronic obstructive pulmonary disease, NMD, and chest wall disease. The comfort and efficacy of these therapies can be improved in several forms.

[0014] Invasive ventilation (IV) provides ventilatory support to patients who can no longer breathe effectively on their own, and may be provided using a tracheostomy tube. The comfort and effectiveness of these treatments can be improved in several ways.

[0015] 2.2.3 Respiratory Therapy Systems These respiratory therapies may be provided by respiratory therapy systems or devices. Such systems and devices may also be used to screen, diagnose, or monitor disease without providing treatment.

[0016] The respiratory therapy system can include a respiratory pressure therapy device (RPT device), an air circuit, a humidifier, a patient interface, an oxygen source, and data management.

[0017] 2.2.3.1 Patient Interface The patient interface may be used to connect a respiratory device to a wearer, for example, by supplying an airflow to an airway inlet. The airflow may be provided to the patient's nose and / or mouth via a mask, to the mouth via a tube, or to the patient's trachea via a tracheotomy tube. Depending on the treatment being applied, the patient interface may, for example, form a seal with an area of ​​the patient's face to facilitate delivery of gas at a pressure sufficiently different from ambient pressure, thereby allowing treatment at a positive pressure of, for example, about 10 cmH2O relative to ambient pressure.

[0018] 2.2.3.2 Respiratory Pressure Therapy (RPT) Devices Respiratory pressure therapy (RPT) devices can be used alone or as part of a system to deliver one or more of the above therapies, for example by operating the device to generate and deliver airflow to an airway interface. The airflow can be pressure controlled (for respiratory pressure therapy) or flow controlled (for flow therapy such as HFT). Thus, RPT devices may also be configured to function as flow therapy devices. Examples of RPT devices include CPAP devices and mechanical ventilators.

[0019] 2.2.3.3 Air Circuit An air circuit is a conduit or tube constructed and arranged to allow airflow between two components of a respiratory therapy system (e.g., an RPT device and a patient interface) in use. In some cases, there may be separate branches of the air circuit for inspiration and expiration. In other cases, a single limb air circuit is used for both inspiration and expiration.

[0020] 2.2.3.4 Humidifier Delivering airflow without humidification can cause drying of the airway. The use of a humidifier with the RPT device and patient interface produces humidified gas, minimizing drying of the nasal mucosa and improving airway comfort for the patient. Additionally, in cooler climates, warm air, which is typically applied to the facial area in and around the patient interface, is more comfortable than cool air. Thus, humidifiers often have the ability to both heat the airflow and humidify the airflow.

[0021] 2.2.4 Component Identification As previously mentioned, respiratory therapy systems generally include components such as an RPT device, a humidifier, an air circuit, and a patient interface. A variety of different types of patient interfaces can be used with a given RPT device, such as nasal pillows, nasal prongs, a nasal mask, a nose and mouth (oronasal) mask, or a full face mask. Also, air circuits of different lengths and diameters can be used. To provide improved control of the therapy delivered to the patient interface, it can be advantageous to estimate therapy parameters such as pressure, leak flow rate, and ventilation flow rate at the patient interface. In systems that use therapy parameter estimation, knowing the type of components the patient is using can improve the accuracy of the therapy parameter estimation and improve the effectiveness of the therapy.

[0022] To gain knowledge of component types, some RPT devices include a patient interface that includes a menu system that allows the patient to input or select the type of system component being used, e.g., brand, form, model, etc. Once the patient inputs the component type, the RPT device can select the appropriate operating parameters of the flow generator that are optimally tuned for the selected component, allowing therapy parameters to be more accurately monitored during treatment. However, it is possible for the patient to select the component type incorrectly or not select the component type at all, causing the RPT device to encounter errors or to be unaware of the type of component being used.

[0023] A range of solutions associated with component identification have been adopted or proposed in the past in the field of respiratory therapy. However, integrating expensive electrical and / or mechanical features into frequently replaced component(s) (e.g., patient interfaces) can be detrimental to providing cost-effective therapy and environmentally unsustainable due to increased waste.

[0024] Furthermore, many of the proposed solutions regarding sensors and / or transducers may be limited if the proposed sensor is located far away from the location that stores and / or analyzes its data, as this may generally further increase the complexity and / or cost of implementation. For example, if the patient interface includes a sensor, it may require an electrical connection to the RPT device, which may further increase the complexity and / or cost of implementation.

[0025] Additionally, designers of RPT devices are faced with many choices, which often result in different solutions when compared to other devices on the market (e.g., devices manufactured by competitors or, indeed, devices manufactured by the same manufacturer at different times). As a result, the associated electrical connectors provided may only be compatible with certain RPT devices. This may have the unforeseen effect of creating ill-fitting that may disadvantage certain subsections of consumers and / or reduce consumer choice.

[0026] Therefore, improved devices and methods are needed to characterize components within respiratory therapy systems, for example to automatically identify components within respiratory therapy systems and to more accurately estimate therapy parameters such as leak flow rates. Summary of the Invention

[0027] 3. Overview of Technology The present technology aims to provide medical devices having one or more of improved comfort, cost, effectiveness, ease of use, and manufacturability for use in screening, diagnosing, monitoring, ameliorating, treating, or preventing respiratory diseases.

[0028] A first aspect of the present technology relates to a device for use in screening, diagnosing, monitoring, ameliorating, treating or preventing respiratory disease.

[0029] Another aspect of the technology relates to methods used to screen for, diagnose, monitor, ameliorate, treat or prevent respiratory disease.

[0030] The disclosed technology relates to an apparatus and method for automatic characterization of a respiratory therapy system, such as by statistical analysis of sensor signals over a therapy period, in a leak-tolerant manner. Additionally, the apparatus and method may be configured to determine a pressure drop during a therapy period based on the characterization of the therapy system. Additionally, the apparatus and method may be configured to determine an actual patient interface pressure based on the pressure drop during a therapy period and / or the characterization of the therapy system. Additionally, the apparatus and method may be configured to estimate a leak flow rate during a therapy period based on the characterization of the therapy system. A characteristic of the respiratory therapy may be adjusted based on the characteristic and / or the estimated leak flow rate. One or more operations of the respiratory device, such as a characteristic of the respiratory therapy or control of the therapy, may be altered by the controller based on the pressure drop and / or the determined actual patient interface pressure. Additionally, the therapy user may be given feedback regarding the user's experience or preference for one or other particular settings by a connectivity application operating within another interface of the device or system, such as a remote computing device (e.g., a smartphone or tablet) that may communicate directly or indirectly with the respiratory device over a network. For example, at some point after a setting has been changed, the user may be allowed to select whether the new setting is more comfortable or uncomfortable than the previous setting. User preferences may be factored into the algorithm to determine preferred settings for therapy. Other factors may also be factored into the algorithm, such as time of use, number or speed of respiratory vents, or other modes or parameters of use.

[0031] Some implementations of the technology may include a respiratory therapy device. The device may include a pressure generator configured to generate an airflow for delivery to a patient interface via a delivery conduit for respiratory therapy of the patient. The patient interface may include a vent. The device may include a pressure transducer configured to generate a signal representative of a pressure of the airflow at the pressure generator. The device may include a flow transducer configured to generate a signal representative of a flow rate of the airflow. The device may include a controller. The controller may be configured to receive the pressure signal and the flow signal from the transducer. The controller may be configured to analyze the pressure signal and the flow signal to determine a system curve representative of pressure and flow characteristics of a respiratory therapy system that may include the device, the delivery conduit, and the patient interface. The controller may be configured to access data associated with a component curve representative of pressure and flow characteristics of at least one component of the system. The controller may be configured to derive a pressure drop parameter that is characteristic of a pressure drop across a vent of the patient interface and / or a pressure drop to the patient interface (e.g., from a sensor of the flow generator) based on a first function characterizing the system curve and a second function representative of the component curve. The controller may be configured to provide an output based on the derived pressure drop parameter.

[0032] In some implementations, the output includes storing data indicative of the derived pressure drop parameter in a storage device of the remote server, generating one or more signals to control operation of a pressure generator to adjust an attribute of the airflow based on the pressure drop parameter, displaying information indicative of the derived pressure drop parameter on a display of the respiratory therapy device, and transmitting information indicative of the derived pressure drop parameter to the remote server. The second function may characterize a curve representing pressure and flow characteristics of the vent of the patient interface. The first function may be a quadratic function. The first function may include a lookup table associated with pressure values ​​and flow values. The second function may include a quadratic function. The second function may include a lookup table associated with pressure values ​​and flow values.

[0033] In some implementations, to derive the pressure drop parameter, the controller may be configured to determine a difference between the first function and the second function. The difference may include a difference between a first reference pressure drop parameter that is characteristic of the pressure drop from the pressure generator to atmosphere through the system and a second reference pressure drop parameter that is characteristic of the pressure drop from the vent to atmosphere. The controller may be configured to determine the first reference pressure drop parameter by applying a measurement of flow rate from the flow transducer to the first function. The controller may be configured to determine the second reference pressure drop parameter by applying a measurement of flow rate from the flow transducer to the second function. The controller may be configured to subtract the second reference pressure drop parameter from the first reference pressure drop parameter to derive the pressure drop parameter that is characteristic of the pressure drop from the pressure generator to the patient interface.

[0034] In some implementations, the controller may be configured to generate one or more signals for controlling operation of the pressure generator to control the pressure in the patient interface by adding a pressure drop parameter derived as a characteristic of the pressure drop from the pressure generator to the patient interface to a target therapy pressure parameter, (a) comparing the result of the addition to a measurement of device pressure from a pressure transducer, and controlling one or more blower drive parameters based on the comparison, or (b) using the result of the addition to control one or more of the blower drive parameters. The controller may be configured to generate one or more signals for controlling operation of the pressure generator to control the pressure in the patient interface by subtracting a pressure drop parameter derived as a characteristic of the pressure drop from the pressure generator to the patient interface from a target therapy pressure parameter, and comparing the result of the subtraction to a measurement of pressure from a pressure transducer. The controller may be configured to generate one or more signals for controlling operation of the pressure generator to control the pressure in the patient interface by adding a pressure drop parameter derived as a characteristic of the pressure drop from the pressure generator to the patient interface to a measurement of pressure from a pressure transducer, and comparing the result of the addition to the target therapy pressure parameter.

[0035] The controller may be configured to detect one or more vents for sleep disordered breathing by evaluating one or more signals received from a pressure transducer and / or a flow transducer, and modify a target therapy pressure parameter based on the evaluation. The one or more vents may include vents from a group of apnea, hypopnea, snoring, and inspiratory flow limitation. The controller may be configured to determine an actual pressure in the patient interface by subtracting (a) a pressure drop parameter characteristic of the pressure drop from the pressure generator to the patient interface from (b) a pressure drop parameter derived from a measurement of pressure determined from a signal received from the pressure transducer.

[0036] In some implementations, analysis of the pressure and flow signals to determine a curve representative of the pressure and flow characteristics of the system may select a value of the curve corresponding to therapy use when mask leak is substantially zero. The analysis may include determining parameters for best fitting a template curve to a plurality of points, each of the points may include (a) a pressure value, and (b) a flow value at the pressure value. The controller may be a central controller of the pressure generator. The central controller may be configured to determine an identification of a patient interface based on the template curve. The curve representative of the pressure and flow characteristics of the system may include (a) a pressure value including a value of a low-pass filtered version of a measured pressure from the pressure signal, and (b) a flow value including a value of a low-pass filtered version of a measured flow from the flow signal at the pressure value. The controller may be configured to use and analyze the pressure and flow signals generated by the pressure and flow transducers during a therapy session including an automatic positive airway pressure (APAP) therapy.

[0037] Some implementations of the present technology may include a method of operating a respiratory treatment device that may include a pressure generator configured to generate an airflow for delivery to a patient interface via a delivery conduit used for respiratory therapy of the patient. The patient interface may include a vent. The method may include receiving a pressure signal generated by a pressure transducer. The pressure signal may represent a pressure of the airflow at the pressure generator. The method may include receiving a flow signal generated by a flow transducer. The flow signal may represent a flow rate of the airflow. The method may include analyzing the pressure signal and the flow signal to determine a system curve representing pressure and flow characteristics of a respiratory therapy system that may include a device, a delivery conduit, and a patient interface. The method may include accessing data associated with a component curve representing pressure and flow characteristics of at least one component of the system. The method may include deriving a pressure drop parameter across a vent of the patient interface and / or a pressure drop that is characteristic of the pressure drop to the patient interface based on a first function characterizing the system curve and a second function representative of the component curve. The method may include implementing an output based on the derived pressure drop parameter.

[0038] In some implementations, the output may include storing data indicative of the derived pressure drop parameter in a storage device of a remote server. The output may include displaying information indicative of the derived pressure drop parameter on a display of the respiratory therapy device. The output may include generating one or more signals to control operation of a pressure generator to adjust an attribute of the airflow based on the pressure drop parameter. The output may include transmitting information indicative of the derived pressure drop parameter to a remote server.

[0039] In some implementations, the second function characterizes a curve representing pressure and flow characteristics of a vent of the patient interface. The first function may be a quadratic function. The first function may include a lookup table associated with pressure values ​​and flow values. The second function may include a quadratic function. The second function may include a lookup table associated with pressure values ​​and flow values. In some implementations, deriving the pressure drop parameter may include determining a difference between the first function and the second function. The difference may include a difference between a first reference pressure drop parameter that is characteristic of a pressure drop from a pressure generator through the system to atmosphere and a second reference pressure drop parameter that is characteristic of a pressure drop from the vent to atmosphere. The method may include determining the first reference pressure drop parameter by applying a measurement of flow of a flow transducer to the first function. The method may include determining the second reference pressure drop parameter by applying a measurement of flow of a flow transducer to the second function. The method may include subtracting a second reference pressure drop parameter from a first reference pressure drop parameter to derive a pressure drop parameter characteristic of the pressure drop from the pressure generator to the patient interface. The method may include adding the derived pressure drop parameter characteristic of the pressure drop from the pressure generator to the patient interface to a target therapy pressure parameter, and (a) comparing a result of the addition with a measurement of the device pressure from a pressure transducer and controlling one or more blower drive parameters based on the comparison, or (b) using the result of the addition to generate one or more signals for controlling operation of the pressure generator to control the pressure at the patient interface by controlling one or more of the blower drive parameters. The method may include subtracting the derived pressure drop parameter characteristic of the pressure drop from the pressure generator to the patient interface from the target therapy pressure parameter and comparing a result of the subtraction with a measurement of the pressure from the pressure transducer to generate one or more signals for controlling operation of the pressure generator to control the pressure at the patient interface.The method may include a step of controlling operation of the pressure generator to generate one or more signals for controlling the pressure at the patient interface by adding a pressure drop parameter derived as a characteristic of the pressure drop from the pressure generator to the patient interface to a pressure measurement from the pressure transducer and comparing the result of the addition with a target therapy pressure parameter.

[0040] In some implementations, the method may include detecting one or more vents for sleep disordered breathing by evaluating one or more signals received from a pressure transducer and / or a flow transducer, and modifying a target therapy pressure parameter based on the evaluation. The one or more vents may include vents from a group of apnea, hypopnea, snoring, and inspiratory flow limitation. The method may further include determining an actual pressure in the patient interface by subtracting (a) a pressure drop parameter characteristic of the pressure drop from the pressure generator to the patient interface from (b) a pressure drop parameter derived from a pressure measurement determined from a signal received from the pressure transducer. In some implementations, an analysis of the pressure and flow signals to determine a curve representative of pressure and flow characteristics of the system selects a value of the curve corresponding to a therapy use when mask leak is substantially zero. The analysis includes determining parameters for best fitting a template curve to a plurality of points. Each of the plurality of points includes (a) a pressure value and (b) a flow value at the pressure value. In some implementations, a controller of a pressure generator may perform the method. The controller may determine an identification of the patient interface based on a template curve. The curve representing the pressure and flow characteristics of the system may include (a) pressure values ​​including values ​​of a low-pass filtered version of a measured pressure from the pressure signal, and (b) flow values ​​including values ​​of a low-pass filtered version of a measured flow from the flow signal at the pressure values. The analysis may use pressure and flow signals generated by the pressure and flow transducers during a therapy session including automatic positive airway pressure (APAP) therapy.

[0041] In some implementations, the analysis and / or derivation may be performed by one or more remote servers configured to communicate with the respiratory treatment device to receive data for analysis and / or derivation (e.g., curves and / or pressure and flow signal data) from the respiratory treatment device. The one or more remote servers may be configured to communicate output with the respiratory treatment device, where the communicated output may include data based on the analysis and / or derivation (e.g., system or component curve(s)), derived pressure drop parameter(s), and / or setting(s) of operation of the respiratory treatment device based on the derived pressure drop parameters (e.g., including one or more of therapy settings).

[0042] Some implementations of the present technology may include a processor-readable medium configured with program instructions for controlling one or more processors to execute a method of operating a respiratory treatment device. The respiratory treatment device may include a pressure generator configured to generate an airflow through a delivery conduit to a patient interface for respiratory therapy for the patient. The patient interface may include a vent. The method may include any one or more aspects of the methods described herein.

[0043] Some implementations of the present technology may include a respiratory treatment device. The respiratory treatment device may include a pressure generator configured to generate an airflow for delivery to a patient interface via a delivery conduit for respiratory therapy of the patient. The patient interface may include a vent. The respiratory treatment device may include a pressure transducer configured to generate a signal representative of a pressure of the airflow. The respiratory treatment device may include a flow transducer configured to generate a signal representative of a flow rate of the airflow. The respiratory treatment device may include a controller, which may include one or more processors having any processor-readable medium described herein.

[0044] Some implementations of the present technology may include a system for controlling a respiratory therapy. The system may include means for delivering an airflow to a patient interface as a respiratory therapy. The system may include means for generating a flow signal representative of the flow rate of the airflow. The system may include means for generating a pressure signal representative of the pressure of the airflow. The system may include means for analyzing the pressure and flow signals to determine a system curve representative of the pressure and flow characteristics of a system that may include a delivery conduit and a patient interface. The system may include means for deriving a pressure drop parameter that is characteristic of the pressure drop across a vent of the patient interface and / or to the patient interface based on a first function characterizing the system curve and a second function representative of a component curve representative of the pressure and flow characteristics of at least one component of the system. The system may include means for generating an output based on the pressure drop parameter.

[0045] Some implementations of the present technology may include an apparatus for respiratory therapy. The apparatus may include a pressure generator configured to generate an airflow for delivery to a patient interface for respiratory therapy of the patient. The apparatus may include a pressure transducer configured to generate a signal representative of a pressure of the airflow. The apparatus may include a flow transducer configured to generate a signal representative of a flow rate of the airflow. The apparatus may include a controller. The controller may be configured to receive a pressure signal and a flow signal from the transducer. The controller may be configured to analyze the pressure signal and the flow signal to identify the patient interface. The apparatus may include a central controller of the pressure generator. The central controller may be configured to receive the identification of the patient interface. The central controller may be configured to control the pressure generator to adjust attributes of the airflow based on the identification. The analysis may include determining parameters for optimally fitting a template curve to a plurality of points. Each of the plurality of points may include (a) a pressure value and (b) a flow value at the pressure value.

[0046] In some implementations, the controller may be a central controller of the pressure generator. The controller may be a processor of a remote external device in communication with the central controller of the pressure generator. The central controller may be configured to determine an identification of the patient interface based on the determination of the parameter. The central controller may be configured to determine a control parameter for adjusting an attribute of the airflow. The central controller may be configured to adjust the control parameter based on the determination of the parameter. The pressure value may be a flow value including a value of a low pass filtered version of a measured flow rate from the flow signal at said pressure value. The flow value may be a mode of a histogram of measured flow rates from the flow signal at the pressure value. The controller may be configured to determine a mode of the histogram of values, and the histogram of values ​​may be a histogram of a low pass filtered version of a measured flow rate from the flow signal at the pressure value. The controller may be configured to analyze the pressure signal by subtracting a pressure drop from a measured pressure. The pressure drop may be a pressure drop in an air circuit connecting the device to the patient interface at the measured flow rate from the flow signal.

[0047] In some implementations, the controller may be configured to determine a plurality of points during a therapy session that may include an automated positive airway pressure ventilation (APAP) therapy. The controller may be configured to adjust the analysis in checking the duration of therapy use and / or the range of the delivered therapy pressure of the therapy session. The controller may be configured to estimate a leak flow rate from a measured pressure from the pressure signal, a measured flow rate from the flow signal, and the determined parameters. The controller may be configured to determine a bias flow rate based on a pressure-flow curve defined by the determined parameters. The controller may be configured to determine a leak flow rate estimate by subtracting the bias flow rate from the measured flow rate, where the measured flow rate may be the total flow rate. The pressure-flow curve defined by the determined parameters may include a quadratic function. The controller may be configured to determine the bias flow rate by inverting the pressure-flow curve defined by the determined parameters. The controller may be configured to estimate a patient's respiratory flow rate from the measured flow rate, the measured pressure, the determined parameters, and the estimated leak flow rate. To control the adjustment of the airflow characteristics, the central controller may be configured to detect an event from the patient's estimated respiratory flow and to adjust the treatment pressure of the airflow in response to the detected event, which may be an event from the group consisting of apnea, hypopnea, snoring, and inspiratory flow limitation.

[0048] In some implementations, the analysis of the device may further include comparing the determined parameters to a plurality of parameter sets in a database. The analysis of the device may further include identifying a patient interface based on a comparison of the determined parameters. The template curve may be a quadratic function. The controller may be configured to determine a vent obstructed vent based on the determined parameters. The controller may be configured to determine a vent obstructed vent based on comparing a measurement of average total flow at a given device pressure to a flow rate according to a function including the determined parameters. The controller may be configured to generate an indication of a vent obstructed vent, for example, when the measurement of average total flow is less than the flow rate according to the function.

[0049] Some implementations of the present technology may include a method of operating a respiratory treatment device that may be configured to generate an airflow for delivery to a patient interface for respiratory therapy for the patient. The method may include accessing data representative of a measured pressure of the airflow generated with a pressure transducer. The method may include accessing data representative of a measured flow rate of the airflow generated with a flow transducer. The method may include analyzing the measured pressure and measured flow rate in a controller to identify the patient interface. The analysis may include determining parameters for best fitting a template curve to a plurality of points. Each of the plurality of points may include (a) a pressure value and (b) a flow rate value at the pressure value.

[0050] In some implementations, the controller may determine an identification of the patient interface based on the determination of the parameter. The method may further include controlling a determination of a value of a control parameter for operating a pressure generator of the respiratory treatment device based on the identification of the patient interface. The method may further include deriving a pressure value by low-pass filtering the measured pressure. The method may further include determining a flow value by deriving a histogram of the measured flow rate at the pressure values, and determining a mode of the histogram. Deriving the histogram may include determining a value of a low-pass filtered version of the measured flow rate at the pressure values. The method may further include subtracting a pressure drop value from the measured pressure to analyze. The pressure drop value may represent a pressure drop in an air circuit connecting the respiratory treatment device to the patient interface at the measured flow rate. The controller may determine values ​​of the multiple points utilizing data from a therapy session, which may include automatic positive airway pressure (APAP) therapy. The method may further include adjusting the analysis based on a check of the duration of therapy use and / or a range of delivered therapy pressures of the therapy session. The method may further include estimating a leak flow rate from the measured pressure, the measured flow rate, and the determined parameters. The method may further include determining a bias flow rate based on a pressure-flow curve defined by the determined parameters. Determining the leak flow rate estimate may include subtracting the bias flow rate from the measured flow rate. The measured flow rate may be a total flow rate.

[0051] In some implementations, the pressure-flow curve defined by the determined parameters may include a quadratic function. The method may further include determining a bias flow rate by inverting the pressure-flow curve defined by the determined parameters. The method may further include estimating a patient's respiratory flow rate from the measured flow rate, the measured pressure, the determined parameters, and the estimated leak flow rate. The method may further include detecting a vent based on the patient's estimated respiratory flow rate. The method may further include adjusting a therapeutic pressure of the airflow in response to the detected vent. The vent may be a vent from the group consisting of apnea, hypopnea, snoring, limited inhalation, and the like. The analysis may further include comparing the determined parameters to a plurality of parameter sets in a database. The analysis may further include identifying a patient interface based on the determined parameters. The template curve may be a quadratic function. The method may further include determining a vent obstructed vent based on the determined parameters. Determining a vent obstructed vent may include comparing a measurement of the average total flow rate at a given device pressure to the flow rate according to a function including the determined parameters. The method may include generating an indication of a blocked vent, such as whether the measured average total flow is less than the flow according to this function.

[0052] Some implementations of the present technology include a communications system. A processor-readable medium comprising program instructions for controlling one or more processors to perform a method of operating a respiratory treatment device. The method may include any one or more step(s) of the method operations described herein.

[0053] Some implementations of the present technology may include a respiratory treatment device. The respiratory treatment device may include a pressure generator configured to generate an airflow for delivery to a patient interface for respiratory therapy of the patient. The respiratory treatment device may include a pressure transducer configured to generate a signal representative of the pressure of the airflow. The respiratory treatment device may include a flow transducer configured to generate a signal representative of the flow rate of the airflow. The respiratory treatment device may include a controller. The controller may include one or more processors having any of the processor-readable media described herein.

[0054] Some implementations of the present technology may include a system for controlling respiratory therapy. The system may include means for delivering an airflow to a patient interface as a respiratory therapy. The system may include means for generating a flow signal representative of the flow rate of the airflow. The system may include means for generating a pressure signal representative of the pressure of the airflow. The system may include means for analyzing the flow signal and the pressure signal to identify a patient interface. The system may include means for adjusting the airflow attributes based on the identified patient interface. The analysis of the device used for the analysis may include determining parameters that best fit a template curve to a plurality of points, each point may include (a) a pressure value and (b) a flow value at that pressure value.

[0055] The described methods, systems, devices, and apparatus may be implemented to improve the functionality of a processor, such as a processor of a special purpose computer, a respiratory monitor, and / or a respiratory therapy device. Additionally, the described methods, systems, devices, and apparatus may provide improvements in the art of automatically managing, monitoring, and / or treating respiratory conditions (including, for example, sleep-disordered breathing).

[0056] Of course, some of these aspects may form sub-aspects of the present technology. Furthermore, each of the sub-aspects and / or aspects may be combined in various ways and may form additional aspects or sub-aspects of the present technology.

[0057] Other features of the technology will become apparent from consideration of the information contained in the following detailed description, abstract, drawings, and claims. [Brief description of the drawings]

[0058] 4. Brief Description of the Drawings The present technology is illustrated by way of example, and not by way of limitation, in the accompanying figures of the accompanying drawings, in which similar elements are designated by the same reference numerals, including:

[0059] 4.1 Respiratory Therapy Systems [Figure 1A] The system is shown including a patient 1000 wearing a patient interface 3000 in the form of nasal pillows that receives a positive pressure air supply from an RPT device 4000. Air from the RPT device 4000 is conditioned in a humidifier 5000 and transmitted along an air circuit 4170 to the patient 1000. A bed partner 1100 is also shown.

[0060] [Figure 1B] The system is shown to include a patient 1000 wearing a patient interface 3000 in the form of a nasal mask that receives air at positive pressure supplied from an RPT device 4000. Air from the RPT device is humidified in a humidifier 5000 and transmitted along an air circuit 4170 to the patient 1000.

[0061] [Figure 1C] The system is shown to include a patient 1000 wearing a patient interface 3000 in the form of a full face mask that receives air at positive pressure supplied from an RPT device 4000. The air from the RPT device is humidified in a humidifier 5000 and transmitted along an air circuit 4170 to the patient 1000.

[0062] 4.2 Respiratory System and Facial Anatomy [Diagram 2] Outline of the human respiratory system including the nasal and oral cavities, larynx, vocal folds, esophagus, trachea, bronchiolungs, alveolar sacs, heart and diaphragm.

[0063] 4.3 Patient Interface [Diagram 3] 1 shows a patient interface in the form of a nasal mask in accordance with one form of the present technology.

[0064] 4.4 RPT Devices [Figure 4A] FIG. 1 illustrates an RPT device in accordance with one form of the present technology.

[0065] [Figure 4B] 1 is a schematic diagram of an air pressure path of an RPT device in accordance with one form of the present technology. The upstream and downstream directions are indicated with reference to the blower and the patient interface. Regardless of the actual flow direction at a particular moment, the blower is defined to be upstream of the patient interface, and the patient interface is defined to be downstream of the blower. Items located in the air pressure path between the blower and the patient interface are located downstream of the blower and upstream of the patient interface.

[0066] [Figure 4C] FIG. 1 is a schematic diagram of electrical components of an RPT device in accordance with one form of the present technology.

[0067] [Figure 4D] FIG. 1 is a schematic diagram of an algorithm implemented within an RPT device in accordance with one form of the present technology.

[0068] [Figure 4E] 4D in accordance with one form of the present technology.

[0069] 4.5 Humidifier [Figure 5A] FIG. 1 shows an isometric view of a humidifier in accordance with one form of the present technology.

[0070] [Figure 5B] FIG. 1 shows an isometric view of a humidifier in accordance with one form of the present technology, showing the humidifier reservoir 5110 removed from the humidifier reservoir dock 5130.

[0071] 4.6 Respiratory waveform [Figure 6A] 1 shows a model of a typical breathing waveform for a sleeping human.

[0072] [Figure 6B] Selected polysomnography channels (pulse oximetry, flow, chest motion, and abdominal motion) of a patient during approximately 90 seconds of normal non-REM sleep breathing are shown.

[0073] [Figure 6C] 1 shows a polysomnography of a patient before treatment.

[0074] [Figure 6D] 1 shows flow data for a patient as the patient experiences a series of total obstructive apneas.

[0075] [Figure 7] 1 is a schematic diagram of an air circuit, a patient interface, and a model of a patient in a respiratory pressure therapy system.

[0076] [Figure 8] 1 includes an exemplary diagram of a curve relating average device pressure to average total flow rate in the absence of leak flow.

[0077] [Figure 8B] 1 includes a pressure-flow curve for an example vent of an example of the present technology.

[0078] [Figure 9]Included is a graph with plotted points representing average device pressure and average total flow over the duration of APAP therapy.

[0079] [Figure 10] A histogram of average total flow values ​​for a given device pressure over the duration of respiratory pressure therapy.

[0080] [Figure 11] 1 includes a flowchart illustrating a method for characterizing a respiratory therapy system in accordance with one form of the present technology.

[0081] [Figure 12] 13 is a flowchart illustrating a method for estimating a leak flow rate in accordance with one aspect of the present technology.

[0082] [Figure 13] 13A and 13B include a flow chart illustrating an exemplary method for dynamically determining the pressure drop ΔPdd-mask across the patient interface. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0083] 5 Detailed description of examples of the present technology Before describing the present technology in more detail, it is to be understood that the present technology is not limited to the specific examples described herein, as these examples may vary, and it should be understood that the terminology used in this disclosure is used only to describe the specific examples described herein, and is not intended to be limiting.

[0084] The following description is provided in conjunction with various examples that may share one or more common characteristics and / or features. It should be understood that one or more characteristics of any example may be combined with one or more characteristics of another example or the other examples. In addition, any single feature or combination of features in any example may constitute an additional example.

[0085] 5.1 Therapy The technology may be applied, for example, to methods for treating respiratory disorders, such as controlling the application of positive pressure to the entrance of the patient's 1000 airways.

[0086] 5.2 Respiratory Therapy Systems The present invention can be applied to a respiratory therapy system for treating respiratory disorders. The respiratory therapy system can include an RPT device 4000 that provides airflow to a patient 1000 via an air circuit 4170 and a patient interface 3000.

[0087] 5.3 Patient Interface A non-invasive patient interface 3000 according to one aspect of the present technology includes as functional aspects a seal-forming structure 3100, a plenum chamber 3200, a positioning and stabilizing structure 3300, a vent 3400, a form of connection port 3600 for connection to an 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 can provide one or more functional aspects. In use, the seal-forming structure 3100 is positioned to surround the entrance(s) of the patient's airway 1000 to maintain positive pressure at the entrance of the patient's airway 1000. The sealed patient interface 3000 is thus suitable for delivery of positive pressure therapy.

[0088] 5.3.1 Vents In one form, the patient interface 3000 includes a vent 3400 constructed and arranged to allow the exhalation of exhaled gases, for example carbon dioxide.

[0089] In certain forms, the vent 3400 is configured to allow continuous ventilation flow from the interior of the plenum chamber 3200 to the ambient while the pressure within the plenum chamber is positive relative to the ambient. The vent 3400 is configured to have a ventilation flow rate large enough to reduce rebreathing of CO2 inhaled by the patient while maintaining a therapeutic pressure within the plenum chamber during use.

[0090] A vent 3400 in accordance with one form of 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.

[0091] The vent 3400 may be located on the plenum chamber 3200. Alternatively, the vent 3400 is located in a separate structure, such as a swivel.

[0092] 5.4 Air Circuit The air circuit 4170 according to one aspect of the present technology is a conduit or tube constructed and arranged to allow air flow to travel between two elements of a respiratory therapy system (e.g., the RPT device 4000 and the patient interface 3000 or 3800) when in use.

[0093] In particular, the air circuit 4170 may be fluidly connected to an outlet of the pneumatic block 4020 and the patient interface 3000. The air circuit may be referred to as a delivery tube (supply tube).

[0094] 5.4.1 Auxiliary gas supply In one form of the present technology, an auxiliary gas, for example oxygen 4180, is delivered to one or more points in the pneumatic pathway, such as upstream of the pneumatic block 4020, the pneumatic circuit 4170, and / or the patient interface 3000 or 3800.

[0095] 5.5 RPT Devices An RPT device 4000 according to one aspect of the present technology includes mechanical, pneumatic, and / or electrical components and is configured to execute one or more algorithms 4300, such as any of the methods described in whole or in part herein. The RPT device 4000 may be configured to generate an airflow for delivery to a patient's airway, such as for the treatment of one or more respiratory disorders described elsewhere herein.

[0096] In one form, the RPT device 4000 is constructed and arranged to be capable of delivering airflow in the range of -20 L / min to +150 L / min while maintaining a positive pressure of at least 6 cmH2O, or at least 10 cmH2O, or at least 20 cmH2O.

[0097] The RPT device may have an outer housing 4010 formed in two portions, an upper portion 4012 and a lower portion 4014. Further, the outer housing 4010 may include one or more panel(s) 4015. The RPT device 4000 includes a chassis 4016 that supports one or more internal components of the RPT device 4000. The RPT device 4000 may include a handle 4018.

[0098] The air pressure path of the RPT device 4000 may include one or more air pressure path items such as an inlet air filter 4112, an inlet muffler 4122, a pressure generator 4140 (e.g., a blower 4142) capable of supplying air at positive pressure, an outlet muffler 4124, and one or more transducers 4270, such as a pressure sensor 4272 and a flow sensor 4274.

[0099] One or more pneumatic path items may be disposed within a movable unitary structure referred to as a pneumatic block 4020. The pneumatic block 4020 may be disposed within the external housing 4010. In one form, the pneumatic block 4020 is supported by or formed as part of the chassis 4016.

[0100] 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 transducer 4270, a data communication interface 4280, and one or more output devices 4290. The electrical components 4200 may be implemented on a single printed circuit board assembly (PCBA) 4202. In the alternative, the RPT device 4000 may include one or more PCBAs 4202.

[0101] 5.5.1 Mechanical and Pneumatic Elements of RPT Devices An RPT device may include one or more of the following components in one overall unit: In the alternative, one or more of the following components may be located as separate units.

[0102] 5.5.1.1 Air filters An RPT device in accordance with one form of the present technology may include an air filter 4110 or multiple air filters 4110.

[0103] In one form, the inlet air filter 4112 is located at the beginning of the air pressure path upstream of the pressure generator 4140 .

[0104] In one form, the outlet air filter 4114, for example an antibacterial filter, is located between the outlet of the pneumatic block 4020 and the patient interface 3000.

[0105] 5.5.1.2 Mufflers An RPT device in accordance with one form of the present technology may include a muffler 4120 or multiple mufflers 4120.

[0106] In one form of the present technology, an inlet muffler4122 is positioned in the pneumatic path upstream of a pressure generator4140.

[0107] In one form of the present technology, the outlet muffler 4124 is placed in the pneumatic path between the pressure generator 4140 and the patient interface 3000.

[0108] 5.5.1.3 Pressure generator In one form of the present technology, the pressure generator 4140 for generating a positive pressure air flow or supply is a controllable blower 4142. For example, the blower 4142 may include a brushless DC motor 4144 having one or more impellers. The impellers may be disposed in a volute. In delivering respiratory pressure therapy, the blower may deliver an air supply at a positive pressure ranging from about 4 cmH2O to about 20 cmH2O, at a rate of, for example, up to about 120 L / min, or in other forms up to about 30 cmH2O. Blowers are described in any one of the following patents or patent applications: U.S. Pat. No. 7,866,944; U.S. Pat. No. 8,638,014; U.S. Pat. No. 8,636,479; and PCT Patent Application No. WO 2013 / 020167, the contents of which are incorporated herein by reference in their entirety.

[0109] The pressure generator 4140 is under the control of the therapy device controller 4240 .

[0110] In other forms, the pressure generator 4140 may be a piston-driven pump, a pressure regulator connected to a high pressure source (eg, a compressed air reservoir), or a bellows.

[0111] 5.5.1.4 Transducers The transducer may be internal to the RPT device or external to the RPT device. An external transducer may, for example, be located on the air circuit or may form part of the air circuit, such as a patient interface. An external transducer may be in the form of a non-contact sensor, such as a Doppler radar motion sensor, that transmits or transfers data to the RPT device.

[0112] In one form of the present technology, one or more transducers 4270 are positioned upstream and / or downstream of the pressure generator 4140. The one or more transducers 4270 may be constructed and arranged to generate a signal representative of a characteristic of the airflow, for example, flow rate, pressure or temperature, at that point in the pneumatic path.

[0113] In one form of the present technology, one or more transducers 4270 may be located proximate to the patient interface 3000.

[0114] In one form, the signal from the transducer 4270 may be filtered, for example, by low pass, high pass, or band pass.

[0115] 5.5.1.4.1 Flow Sensors A flow sensor 4274 according to the present technology may be based on a differential pressure transducer, for example, SENSIRION's SDP600 series differential pressure transducer.

[0116] In one form, a signal representative of the airflow rate generated by the flow sensor 4274 is received by the central controller 4230.

[0117] 5.5.1.4.2 Pressure Sensors A pressure sensor 4272 according to the present technology is positioned in fluid communication with the air pressure path. An example of a suitable pressure sensor is a transducer from the HONEYWELL ASDX series. Another suitable pressure sensor is the NPA series sensor from GE.

[0118] In one form, a signal representative of the pressure of the airflow generated by the pressure sensor 4272 is received by the central controller 4230.

[0119] 5.5.1.4.3 Motor Speed ​​Transducers In one form of the present technology, the motor speed transducer 4276 is used to determine the rotational speed of the motor 4144 and / or the blower 4142. The motor speed signal from the motor speed transducer 4276 may be provided to the therapy device controller 4240. The motor speed transducer 4276 may be a speed sensor, such as, for example, a Hall effect sensor.

[0120] 5.5.1.5 Anti-spillback valves In one form of the present technology, the anti-spillback valve 4160 is located between the humidifier 5000 and the pneumatic block 4020. The anti-spillback valve is constructed and arranged to reduce the risk of water flowing upstream from the humidifier 5000, for example to the motor 4144.

[0121] 5.5.2 Electrical Elements of RPT Devices 5.5.2.1 Power supply The power supply 4210 may be located inside or outside the external housing 4010 of the RPT device 4000.

[0122] In one form of the present technology, the power supply 4210 powers only the RPT device 4000. In another form of the present technology, the power supply 4210 powers both the RPT device 4000 and the humidifier 5000.

[0123] 5.5.2.2 Input Devices In one form of the present technology, the RPT device 4000 includes one or more input devices 4220 in the form of buttons, switches, or turntables that allow a person to interact with the device. The buttons, switches, or dials may be physical devices or software devices accessible via a touch screen. The buttons, switches, or turntables may be physically connected to the external housing 4010 in one form, or may communicate wirelessly with a receiver electrically connected to the central controller 4230 in another form.

[0124] In one form, the input device 4220 may be constructed and arranged to allow a human to select values ​​and / or menu options.

[0125] 5.5.2.3 Central Controller In one form of the present technology, the central controller 4230 is one or more processors suitable for controlling the RPT device 4000.

[0126] Suitable processors may include x86 Intel processors, processors based on the ARM® Cortex®-M processor from ARM Holdings, such as the STM32 series microcontrollers from STMicroelectronics. In certain alternative forms of the present technology, 32-bit RISC CPUs such as the ST MICROELECTRONICS STR9 series microcontrollers manufactured by TEXAS INSTRUMENTS, or 16-bit RISC CPUs such as processors from the MSP430 family of microcontrollers may also be suitable.

[0127] In one form of the present technology, the central controller 4230 is a dedicated electronic circuit.

[0128] In one form, the central controller 4230 is an application specific integrated circuit. In another form, the central controller 4230 includes discrete electronic components.

[0129] The central controller 4230 may be configured to receive input signal(s) from one or more transducers 4270, one or more input devices 4220, and the humidifier 5000.

[0130] The central controller 4230 may be configured to provide output signal(s) to one or more of the output device 4290, the therapy device controller 4240, the data communication interface 4280, and the humidifier 5000.

[0131] In some forms of the present technology, the central controller 4230 is configured to implement one or more methodologies described herein (e.g., one or more algorithms 4300 expressed as a computer program stored in a non-transitory computer-readable storage medium such as memory 4260). In some forms of the present technology, the central controller 4230 may be integrated with the RPT device 4000. However, in some forms of the present technology, some methods may be performed by a remote device. For example, a remotely located device may determine ventilator control settings or detect respiratory-related ventilation by analysis of stored data such as from any of the sensors described herein.

[0132] 5.5.2.4 Clock The RPT device 4000 may include a clock 4232 connected to the central controller 4230 .

[0133] 5.5.2.5 Therapy Device Controllers In one form of the present technology, the therapy device controller 4240 is a therapy control module 4330 that forms part of the algorithm 4300 executed by the central controller 4230.

[0134] In one form of the present technology, the therapy device controller 4240 is a dedicated motor control integrated circuit. For example, in one form, the MC33035 brushless DC motor controller manufactured by ONSEMI is used.

[0135] 5.5.2.6 Protection circuit The one or more protection circuits 4250 in accordance with the present technology may include electrical protection circuits, temperature and / or pressure safety circuits.

[0136] 5.5.2.7 Memory In accordance with one form of the present technology, the RPT device 4000 includes a memory 4260, such as a 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.

[0137] The memory 4260 may be located on the PCBA 4202. The memory 4260 may be in the form of an EEPROM or NAND flash memory.

[0138] Additionally or alternatively, the RPT device 4000 includes a removable form of memory 4260, such as a memory card made in accordance with the Secure Digital (SD) standard.

[0139] In one form of the present technology, the memory 4260 operates as a non-transitory computer-readable storage medium that stores computer program instructions, such as one or more algorithms 4300, that represent one or more methods described herein.

[0140] 5.5.2.8 Data communication systems In one form of the present technology, a data communications interface 4280 is provided and connected to a central controller 4230. The data communications interface 4280 may be connected to a remote external communications network 4282 and / or a local external communications network 4284. The remote external communications network 4282 may be connected to a remote external device 4286. The local external communications network 4284 may be connected to a local external device 4288.

[0141] In one form, the data communication interface 4280 is part of the central controller 4230. In another form, the data communication interface 4280 may be separate from the central controller 4230 and include an integrated circuit or processor.

[0142] In one form, the remote external communications network 4282 is the Internet. The data communications interface 4280 may be connected to the Internet using wired communications (e.g., via Ethernet or optical fiber) or wireless protocols (e.g., CDMA, GSM, LTE).

[0143] In one form, the local external communications network 4284 utilizes one or more communications standards such as Bluetooth or consumer infrared protocols.

[0144] In one form, the remote external device 4286 is one or more computers, such as a cluster of computers connected to a network. In one form, the remote external device 4286 may be a virtual computer rather than a physical computer. In either case, such a remote external device 4286 may be accessible to appropriately authorized personnel, such as a clinician.

[0145] The local external device 4288 may be a personal computer, a mobile phone, a tablet, or a remote control.

[0146] 5.5.2.9 Output devices, including displays and alarms as appropriate. The output device 4290 according to the present technology may take the form of one or more of a visual, auditory and tactile unit. The visual display may be a liquid crystal display (LCD) or a light emitting diode (LED) display.

[0147] 5.5.2.9.1 Display Drivers The display driver 4292 receives as input characters, symbols or images intended to be displayed on the display 4294 and converts them into commands that cause the display 4294 to display them.

[0148] 5.5.2.9.2 Display The display 4294 is configured to visually display characters, symbols, or images in response to commands received from the display driver 4292. For example, the display 4294 may be an eight-segment display, in which case the display driver 4292 converts each character or symbol (e.g., the number "0") into eight logical signals indicating whether eight corresponding segments are activated to display the particular character or symbol.

[0149] 5.5.3 RPT Device Algorithms As mentioned above, in some forms of the present technology, the 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 the memory 4260. The algorithms 4300 may be grouped into groups generally referred to as modules.

[0150] In other forms of the present technology, some or all of the algorithm 4300 may be implemented by a controller of an external device, such as a local external device 4288 or a remote external device 4286. In this form, input signals and / or intermediate algorithm output data required to represent the portion of the algorithm 4300 executed on the external device may be transmitted to the external device via a local external communications network 4284 or a remote external communications network 4282. In such forms, the portion of the algorithm 4300 executed on the external device may be represented as a computer program stored on a non-transitory computer-readable storage medium accessible to the controller of the external device. Such a program configures the controller of the external device to execute the portion of the algorithm 4300.

[0151] In this form, therapy parameters generated by the external device via the therapy engine module 4320 (if such parameters form part of the algorithm 4300 executed by the external device) may be transmitted to the central controller 4230 for transmission to the therapy control module 4330.

[0152] 5.5.3.1 Characterization of the Therapy System In one form of the present technology, a therapy system characterization algorithm (therapy system characterization algorithm) 4305 includes: A signal from a pressure sensor 4272 representing the pressure in the pneumatic path near the outlet of the pneumatic block (the device pressure Pd); a signal from flow sensor 4274 representing the airflow rate (device flow rate Qd) exiting the RPT device 4000; The system receives as input data representing the pressure-flow curve that is characteristic of the respiratory therapy system.

[0153] The therapy system characterization algorithm 4305 is configured to operate on data accumulated from the transducer 4270 during therapy (e.g., an APAP therapy session) during which the pressure delivered may vary. This period should be long enough to encompass a fairly large range of device pressures, such as a range of at least 3 cmH2O. In some implementations, this period is a complete therapy session, while in other implementations, one or two hours may be long enough to accumulate enough data. In some implementations, the early part of the therapy period is discarded. In some implementations, data corresponding to the lower part of the pressure range has more weight in the analysis since leaks are more likely to occur under higher pressures. Thus, in some implementations, the system can perform checks, such as using time and / or measured pressure, to ensure that a sufficient desired range of pressure values ​​have been accumulated to calculate a pressure-flow characteristic curve (e.g., best fit calculation of one or more curve parameters). In one exemplary implementation, the controller of the RPT may control a process at the beginning of therapy that may slowly increase the pressure between relatively low therapy pressures (e.g., between 4 and 7 cmH2O) or for a period of time until enough data is collected to learn the system characteristics described herein. In some implementations, sleep state estimation is performed as described in U.S. Pat. No. 10,874,328 and / or U.S. Patent Application Publication No. 021 / 0205559, the entire disclosures of which are incorporated herein by reference, and data corresponding to arousals may be discarded because the user is likely adjusting the interface causing a leak or blockage. In yet another implementation, multiple learning periods may be used. For example, there may be a rapid learning period to learn the system parameters for a short period of time, such as 5-20 minutes, 60-100 breaths, or until a therapy pressure range is reached, such as 1-3 cmH2O. After the rapid learning period, the estimation accuracy of system parameters such as pressure drop and ventilation-flow curve is expected to be less than optimal, but the results are quickly compensated for.In addition, there may be a slower learning period, such as tens of minutes to multiple therapy sessions, a wider pressure range, or increased respiratory rate, which can be used to learn more accurate estimates of the system parameters and further update the control and reporting algorithms. For example, the process can learn the system ventilation curve during therapy or after a therapy session (during post-processing), so no changes to the therapy process are required (e.g., no special learning circuit mode is required). As described in more detail herein, this process may be based on the assumption that a minimum average flow generator flow at each pressure will be reached in the absence of blockages and leaks in the system. In general, the pressure loss along the path from the pressure and flow sensors to the atmosphere is described by a quadratic relationship between pressure and flow.

[0154] Thus, the therapy system characterization algorithm 4305 may optionally iterate one or more times, in which case, in each iteration, the therapy system characterization algorithm 4305 may refine an estimate of the characteristic pressure-flow curve of the respiratory therapy system.

[0155] Although the methods of learning flow curves described herein may not apply to the relatively small percentage of patients for whom a reasonable mask seal is not achieved at any point during therapy, algorithms may be implemented to detect these marginal situations and generate warnings or messages indicating this potentially more significant problem. Similarly, such learning processes may be programmed to rely on data from during therapy (e.g., using typical seal detection methods) where a seal condition (or a reasonable seal condition) between the mask and the patient is detected, and such data may be used to learn / calculate the system curve. However, for this method, it is possible to learn curves for more than 90% of cases. For patients who experience excessive leak, this method may not be successful.

[0156] 7 is a schematic diagram of a model 7000 of the air circuit 4170, the patient interface 3000, and the patient 1000 downstream of the supplemental gas delivery point 4180. Impedance Z1 represents the air circuit 4170, causing a pressure drop ΔP that is a function of the total flow Qt. The interface pressure Pm is the device pressure Pd minus the pressure drop ΔP through the air circuit.

number

[0157] where ΔP(Qt) is characteristic of the pressure drop in the air circuit 4170.

[0158] Impedance Z2 represents the vent 3400. The ventilation flow Qv is related to the interface pressure Pm by the ventilation characteristic f.

number

[0159] Combining (1) and (2), the device pressure Pd may be written as:

number

[0160] As discussed herein, a sign convention can be adopted such that the flow in the tube to the patient (Qt) is positive and the ventilation flow out of the mask (Qv) is positive. If Qt is positive, then ΔP is defined as positive, and also Pd>Pm.

[0161] Impedance Z3 represents a leak, which is unknown and unpredictable. Impedance Z4, capacitance Clung, and variable pressure source Plung represent the patient's characteristics. As can be seen from the Model 7000, the total flow Qt is equal to the sum of the ventilation flow Qv, the leak flow Qleak and the respiratory flow Qr.

number

[0162] Since the average flow rate in or out of the lungs must be zero, the respiratory flow rate Qr can be approximated by taking the average of the flows over many respiratory cycles.

number

[0163] where the tilde (~) denotes an average value over multiple respiratory cycles. Averaging may be accomplished by low pass filtering with a time constant long enough to include a large number of respiratory cycles. In some implementations, the time constant is 10 seconds, but other time constants may be considered. In some implementations, the time constant may be variable and synchronized to an integer number of respiratory cycles, or to a period of constant pressure. Also, the data may be buffered and the variable time constant may be selected in a post-processing step based on determining the time constant that produces the minimum flow rate corresponding to a particular pressure Pd. In this way, the characterization algorithm may be less susceptible to errors due to unintended leaks.

[0164] Combining equations (3) and (5), the average device pressure

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[0165] When there is no leak flow (Q リーク ==0), average total flow

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[0166] This relationship is called the flow curve, which is the pressure of the system and is determined by the flow characteristic f(Q) and the pressure drop characteristic ΔP(Q) of the air circuit. Figure 8 shows the average total flow rate when there is no leak.

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number

number

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[0167] In one implementation, the pressure-flow curve for a respiratory pressure therapy system can be approximated by a function such as a quadratic function.

number

[0168] In this quadratic implementation, the pressure-flow curve parameters k1 and k2 characterize the series of the flow characteristic f and the air circuit pressure drop characteristic ΔP.

[0169] If the air circuit pressure drop characteristic ΔP(Q) is known, for example because the type of conduit making up the air circuit 4170 is known or through a previous calibration operation, the parameters of the pressure-flow curve effectively characterize the vent 3400, which is indicative of the type of patient interface 3000. Thus, in these cases, the therapy system characterization algorithm 4305 can be used to identify the patient interface 3000. In one implementation, this can be accomplished by comparing the calculated curve parameters (e.g., k1 and k2) to a data structure (e.g., parameters associated with known patient interface types when used with known conduits (e.g., parameter pair (k1, k2)). The patient interface type associated with the stored parameters (e.g., k1 and k2) that most closely match the calculated parameters (e.g., k1, k2) can be considered the type of patient interface 3000. Alternatively, the average device pressure (e.g., k1, k2) can be calculated using a function (e.g., a quadratic function) before fitting the resulting mask pressure-flow curve.

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[0170] Figure 9 shows the points during APAP therapy.

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[0171] As another example, FIG. 10 shows the average device pressure delivered during respiratory pressure therapy.

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[0172] 11 includes a flow diagram illustrating an example method 11000 that may be performed to implement the therapy system characterization algorithm 4305. The method 11000 applies a filter, such as a low pass filter having a time constant having a number of respiratory cycles, to data representing a signal from the pressure sensor 4272, which represents the device pressure Pd, to generate a filtered device pressure Pd.

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[0173] Step 11020 calculates the filtered device pressure.

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[0174] The next step 11030 is to plot the pressure-flow curve.

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[0175] In an optional final step 11040, the method 11000 may compare the determined parameters of the best fitting curve with a set of parameters stored in a database or other suitable data structure, at least some of which may each be associated with a different or specific patient interface. By way of example, the comparison may be performed by a correlation function. Each set of parameters in the database / data structure may be associated with a specific type of patient interface. Optionally, to mitigate the effects of pressure drop through the tubing, the data sets of the various masks may include information of the corresponding tubing or may be collected with the same type of tubing. This comparison identifies the set of parameters that most closely matches the parameters calculated in step 11030. The patient interface type in the database / data structure associated with the parameter set that is closest to the matching calculated parameters may be considered the identification type of the patient interface 3000. Application of such a method may be enhanced by tight control of manufacturing tolerances of the vents, masks and tubing, which may result in tight control of each of the flows through these components (e.g., consistency of performance and / or different values ​​for different models).

[0176] Optionally, an operating parameter(s) of the RPT device may be adjusted by a controller of the RPT device based on the accessed data associated with the most closely matching set of parameters, as described herein. For example, a flow or pressure therapy control parameter, such as the operation of a blower, may be adjusted based on the identification. Optionally, this adjusted control parameter may then be applied by the RPT device to operate the blower to provide any respiratory therapy described herein based on the adjusted control parameter.

[0177] For example, point

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[0178] The application of such a function representing a learning curve may benefit from structural modifications of the patient interface designed to improve the learning that determines the curve function, such as the process of FIG. 11. In this regard, the ventilation structure and / or patient interface may be designed and / or manufactured to promote greater predictability of the ventilation curve characteristics and their influence on the learning curve. For example, such a design may facilitate a more stable or consistent relationship between the pressure through the vent and the flow through the vent, e.g., such that the tolerance of the relationship is unique for different masks or consistent for the same type of mask. Similarly, this stability may be improved by designing the patient interface such that the vent is positioned relative to the plenum chamber of the patient interface such that the pressure difference through the vent through which the airflow passes is substantially equal to the pressure difference between the mask therapy pressure and atmospheric pressure (e.g., the vent drive pressure).

[0179] The stability of the function determining the learning curve representing the system including the vent can also be improved by protecting the vent from external blockages, for example by protecting the vent from being blocked by bedding or fingers (while the patient is adjusting the mask). This may be achieved, for example, by implementing a structural cover of the high flow impedance portion of the vent. Such a cover can be a protective screen, grid or shroud with a distribution or multiple low flow impedance paths to the atmosphere, or multiple high impedance paths. In this respect, the cover can allow smooth passage through the holes of the vent itself, in relation to its designed flow characteristics, while at the same time keeping external obstacles (fingers, pillows) at a sufficient distance to not affect (e.g., restrict) the flow through the holes or to make it less likely that these obstacles will otherwise impede the flow through the holes. Optionally, the patient interface may comprise adjustable vents configured to operate to avoid such blockages by automatically opening some vents or vents and closing other vents or vents that may be subject to such blockages. Such vents are disclosed in U.S. Patent Application Serial No. 17 / 247,272, the entire disclosure of which is incorporated herein by reference. Additionally, in some implementations, the vent structure may be configured to enhance this stability by having a design that reduces the risk of clogging or exposure to humidity (e.g., condensation or other moisture) or other contaminants (e.g., slime) in the system.

[0180] The performance of the technology can benefit from ensuring there is a means to determine if the mask being used has the proper construction with respect to pressure drop and flow characteristics. For example, if the flow characteristics are known and the ventilation driving pressure corresponds to the mask therapy pressure, the system can rely on learned system characteristics as described above and compensate for the mask pressure drop with such dynamic pressure drop determination. There are several architectures that can achieve this, including: This allows for the accurate target mask pressure to be predictably and consistently delivered to the user.

[0181] 1. The use of a lock and key system may be implemented with a checking mechanism to ensure that the therapy device 4000 is only connected to a patient interface that is designed to support the aforementioned methods.

[0182] 2. Use of product marking and user input: In this implementation, the patient interface is clearly marked (e.g., marked on the mask) so that the user is informed to manually enable the aforementioned characterization features of the therapy device 4000 via the input interface.

[0183] 3. Use of Automatic Interface Detection (e.g., Acoustic Detection) - In this implementation, when a patient interface compatible with the functionality is detected, the therapy device 4000 includes an automatic process for detecting the patient interface and can enable any one or more of the characterization detection functions (e.g., determining a template curve and / or parameters determined therefrom, such as dynamic pressure drop, etc.) accordingly. Such automatic detection methodologies may be any of the methodologies disclosed in International PCT Application No. PCT / AU2020 / 050435 and U.S. Patent Application Publication No. US / 2020 / 0114100 / A1, the entire disclosures of which are incorporated herein by reference.

[0184] In some implementations, if the flow characteristics are reasonably constant, the method may be performed to track changes in pressure drop, for example, by comparing dynamic pressure drop parameters derived before and after. Evaluation of such changes may be performed (e.g., by comparing the difference between such parameters to one or more thresholds) to identify changes in the patient's circuit, such as the insertion of an in-line filter, a change in the water level in the humidifier, the insertion, removal or clogging of an in-line humidity exchanger, a clogged or partially clogged conduit. In this regard, different change values ​​may be associated with such changes in the patient interface and detected by comparison. Any or each of the above vents may be associated with a particular predefined parameter change, which may be cataloged and maintained in the memory of the system. Comparing the observed change to each of a set of cataloged possible changes may indicate a high probability of one or more of the above vents. Identifying one or more of the above vents may trigger a response, which may include sending a notification to a user and / or a third party, changing a parameter of the RPT device, etc.

[0185] In some implementations, if the blower characteristics (e.g., the relationship between the blower pressure, flow rate, and angular velocity) are known, a similar method can be implemented to identify changes in inlet impedance, such as the insertion, removal, or clogging of an inlet filter. For example, after using the methods described to determine the pressure-flow relationship of the circuit at the blower outlet, the characteristic fan curve of the blower can be used to approximate the pressure-flow relationship through the blower to determine the expected inlet pressure of the blower, and thus the relationship between the inlet pressure and the flow through the blower can describe the inlet impedance of the flow generator, which changes in response to the presence of a component such as an inlet filter, or changes gradually as the inlet filter becomes clogged. In some implementations, it may be desirable to respond to the estimate of the inlet impedance, for example by prompting the user to check or replace the inlet filter.

[0186] The characterization process based on therapy system characteristics, including leak determination and / or dynamic pressure drop determination as described herein and / or as described in more detail above or below, may be performed entirely by the RPT device, such as utilizing a controller and / or processor(s) as described in more detail herein. However, other configurations are also implementable. For example, the therapy system characterization process may be performed by one or more servers in communication(s) with or receiving(s) or accessing(s) data provided by the RPT device (e.g., pressure and / or flow data). Thus, the learning calculations (e.g., curves) may be realized by the processor(s) of such remote, network, or cloud server. Additionally, the learned functions or other data based thereon (e.g., modified therapy settings, pressure drop, and / or leak data) may be optionally sent back to the RPT device for use / operation of the RPT device. In such an example, the RPT device may be implemented to send blower pressure values ​​and blower flow values ​​to one or more servers. In such cases, pressure and flow average signals (e.g., 1 minute averages or other average(s)) may be sufficient to generate an average leak signal (e.g., .., 1 minute average leak signal or other average). Such improved leak data in such one or more servers, whether determined by such server(s) or determined by the RPT device and transmitted to the server(s), may then improve other leak-based determinations that may be made by such server(s) or RPT device. For example, intra-oral leaks are a specialized leak and may be particularly problematic.As described in U.S. Patent No. 10,328, 219, analysis of data available on such server(s) or RPT devices, such as minute ventilation and determined leaks as described herein, may then be used to determine the type of leak, such as an intraoral leak, the entire disclosure of which is incorporated herein by reference. Such improved leaks as described herein may improve intraoral leak detection. Additionally, leak analysis based on leak determination as described herein may also improve detection of patient problems, and interventions may be initiated based on such improvements.

[0187] 5.5.3.2 Pre-processing module A pre-processing module 4310, according to one form of the present technology, receives as inputs signals from a transducer 4270 (e.g., flow sensor 4274 or pressure sensor 4272) and, optionally, pressure-flow curve parameters estimated by a system characterization algorithm 4305, and performs one or more processing steps to calculate one or more output values ​​that are used as inputs to other modules (e.g., therapy engine module 4320). Thus, the pre-processing module 4310 runs with minimal latency between input and output signals during therapy.

[0188] In one implementation of the present technology, the output values ​​include interface pressure Pm, ventilation flow Qv, respiratory flow Qr, and leak flow Ql.

[0189] In various implementations of the present technology, the pre-processing module 4310 includes one or more algorithms for dynamic pressure drop determination 4311, interface pressure estimation 4312, ventilation flow estimation 4314, leak flow estimation 4316, and respiratory flow estimation 4318.

[0190] 5.5.3.2.1 Dynamic Pressure Drop Determination 4311 As previously mentioned, the pressure drop ΔP of the air flow through the air circuit may be a parameter used by the processor or controller to determine and / or control the pressure in the patient interface. In this regard, such pressure drop ΔP is generally a static characteristic of the patient circuit 4170 that is generally known, as input into the system or determined by a controlled calibration process. In this regard, it is determined in advance (prior to use of the therapy apparatus) and can be used for therapy with the therapy device. Such pressure drop ΔP may be characterized by a pressure-flow curve and is generally maintained constant while the patient circuit is in use with the RPT. However, in some versions of the present technology, the pressure drop in the patient circuit may be determined more dynamically (e.g., using therapy-related data values ​​determined (e.g., calculated) during therapy of the patient, in conjunction with the method of FIG. 11), and the pressure drop may be determined in accordance with the previously discussed points.

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[0191] In one such example, the dynamically determined pressure drop △Pd to the patient interface d-マスクcan be derived from a function that represents the learning curve. This derivation can be considered in conjunction with the model in Figure 7. In the system, the device pressure (Pd) is the pressure from the blower to the atmosphere (P 周囲 ) Pressure drop △P デバイス The patient interface pressure (Pm) can be understood as the pressure drop ΔP through the vent (Z2) to the atmosphere (Pa). Furthermore, the pressure drop to the patient interface (Z1 in FIG. 1) ΔP マスク is the air (P 周囲 ) Pressure drop △P デバイス From there, the atmosphere (P 周囲 ) Pressure drop △P 換気口 From these relationships, the blower pressure or device pressure Pd can be understood as the patient interface ΔP マスク Pressure drop △P at (Z1) 換気口 is understood to be equal to the pressure drop through the vent (Z2) to atmosphere (P ambient). Thus, if it is desired to provide therapy to a patient such that the pressure in the patient interface (e.g., mask) is controlled to a target therapy pressure and the pressure is measured at a distal device that generates the pressure (e.g., a pressure sensor located at the pressure generator), the pressure set by the pressure controller at the pressure generator is the target therapy pressure plus the pressure drop to the patient interface, ΔP マスク In the following example, the patient interface ΔP マスク The pressure drop to the patient interface (Z1) is determined as described herein by the patient interface ΔPd d-マスク The pressure drop may be a dynamically determined pressure drop to

[0192] Pressure drop to the patient interface △PD d-マスクAn example of a method 13000 for enabling dynamic determination of may be considered in connection with the exemplary flow charts of Figures 13A and 13B. The method may be executed by any of the processor(s) or controller(s) of the RPT device 4000 described herein, for example, during a respiratory therapy session that provides therapy to a user wearing a patient interface. Several steps may be performed as prerequisites for executing the method shown in Figure 13B. Method 13000A, which refers to the flow chart of Figure 13A, illustrates such step(s).

[0193] One such example is step 13001, which includes identifying the patient interface to be used with the system. For example, the present technology may utilize any known technology for identifying a patient interface connected to a positive airway pressure ventilation device, such as acoustic, optical, or radio (e.g., NFC) or electrical methods for identifying the patient interface. Alternatively, some embodiments may rely on user input to a user interface of the system, such as a device menu or a connected application, to identify the patient interface being used. For example, a user may select the patient interface to be used from a list of patient interfaces in an application settings menu. In some embodiments, this first step may be negated by design, for example, in the case of a system designed to operate with only one type of interface, or with multiple types of interfaces having the same ventilation flow characteristics.

[0194] Once an interface is identified, the next step may be to determine whether the interface is suitable for process 13000, for example, by determining that it meets the requirements or criteria of the process of method 13000. For example, if the interface model is known to the algorithm, and it is known that the relationship between therapy pressure and ventilation flow has already been characterized or can be characterized, and for a high percentage of samples (e.g., 90%) of this interface model, there is a tight tolerance on the associated therapy pressure for a particular ventilation flow rate, this process may provide a useful output. For example, if the ventilation flow rate is 30 LPM, the associated therapy pressure should be within 5% of 10 cmH2O, or within 2% of 10 cmH2O, for example. According to the design of the interface, the relationship between therapy pressure and ventilation flow rate may be described as a second order polynomial. In other cases, other functions may be more appropriate, or in either case, a lookup table may be used to determine the relationship between therapy pressure and ventilation flow.

[0195] Once the system configuration is determined to be suitable for process 13000, such as by method 13000A, the illustrated method may begin at 13010 measuring or receiving / accessing pressure and flow of the RPT device. The pressure and / or flow may be generated by a sensor(s), such as a device pressure transducer or flow transducer described herein. At 13020, the pressure and flow signals may be analyzed to determine a curve representing the pressure and flow characteristics of the system (e.g., the combination of the device, delivery conduit, and patient interface including vent) and any additional components that may increase the pressure drop between the sensor and the atmosphere, such as an online filter, humidifier, or other system component. Such a process may be similar to, for example, step 11030 of method 11000 described above. Thus, as shown in the bias (no leak) curve of FIG. 8 and FIG. 8B, the curve may be represented by data representing curve 8000 (e.g., a lookup table that functionally relates pressure values ​​to flow values) or a quadratic function. Such a quadratic function may be Equation 8 or a form thereof. This curve can be understood as characterizing the device pressure (the pressure drop from the therapy generator (e.g., a pressure transducer in the pressure generator) to atmosphere or ambient). Optionally, instead of measuring pressure and flow values ​​and deriving the pressure / flow characteristics of the system (e.g., in the form of a curve or equation), at this step the process can simply access data from a previously derived curve for such a system.

[0196] In 13030, a dynamic pressure drop parameter can be derived that characterizes the pressure drop from the therapy generator (e.g., a pressure sensor in the pressure generator) to the patient interface based on a first function that characterizes the learning curve and a second function that characterizes a curve that represents the pressure and flow characteristics of a system component (e.g., a vent). The difference between the two curves can be used to generate a pressure drop as a function of the system flow rate from the sensor to the mask. For example, the first function can be a quadratic function or its data (e.g., the learning curve lookup table described above). See previous references (e.g., WO / 2021 / 072486 or U.S. Patent Application No. 2010 / 0233662) that allow for determining ventilation flow as a function of device pressure. 1716972919781_0 and the disclosures of which are incorporated herein by reference), one can determine the ventilation flow rate for any flow generator pressure. One problem is that without prior knowledge of the system components one cannot use this method to determine how much pressure is being lost at each component. However, for a given system flow rate, if one has determined the ventilation pressure / flow characteristics (based on knowledge of the mask), one can estimate how much pressure is being lost at the vent based on a given ventilation flow rate (which is the same as the given system flow rate estimate without leak locations). Once one knows how much pressure is being lost at the vent for a particular ventilation flow rate, and knows that the atmospheric side of the vent is at atmospheric pressure, one can infer that the pressure in the mask relative to atmospheric pressure is the pressure being lost at the vent. Now one can determine a / the pressure in the mask and b / the pressure drop across the rest of the system (from sensor to mask), i.e. the pressure across the entire system (pressure measured at the sensor) minus the pressure in the mask. Optionally, at 13040, the mask pressure and "to the mask" pressure drop (from sensor to mask) as a function of flow rate in the FG can be learned and this pressure drop can be compensated for to control the mask pressure without relying on prior knowledge of at least some system components such as tube type, online filters, etc. As a result, an output can be generated. Such output may include a / generating one or more signals to control the operation of the therapy generator (e.g., adjusting attributes of the airflow based on the dynamic pressure drop parameters), b / storing and / or displaying the received / derived / calculated data, and forwarding the data to a remote server, etc. Method 13000 can optionally be repeated after any of the processes of 13030 and / or 13040 by returning to 13010.

[0197] Thus, as previously described, the process at 13030 can also be considered to include a second function representing a curve defining the pressure and flow characteristics of a component of the system (e.g., a vent of the patient interface). An example of such a curve is shown in FIG. 8B and relates to the flow rate through the ventilation gas at different ventilation driving pressures (where the ventilation driving pressure corresponds to the pressure of the patient interface). Like the first function, the second function can be a quadratic function or a curve defined by its data (e.g., a look-up table relating pressure to flow rate). Thus, the method can determine a difference between one or more parameters associated with the first and second functions in determining the dynamic pressure drop parameter. This difference can be considered as a difference between the first and second pressure drop parameters. The first pressure drop parameter can be characteristic of the pressure loss from the pressure generator to atmosphere through the system (e.g., from a pressure sensor in the pressure generator, through a delivery conduit of the patient circuit, into the patient interface, through the vent to atmosphere). The second pressure drop parameter can be considered as a pressure loss that is characteristic of the pressure drop from the vent to atmosphere. The first pressure drop parameter can be determined by applying the measurement of flow from the flow transducer to a first function. The first function can thus generate a pressure value associated with the measurement of flow from the flow transducer according to a system-dependent template curve (curve 8000 or 9010). Similarly, the second pressure drop parameter can be determined by applying the measurement of flow from the flow transducer to a second function. The second function can thus generate a pressure value associated with the measurement of flow from the flow transducer according to a ventilation correlation curve (curve 8001). The measurement of flow from the flow transducer used with the first and second functions can optionally be a measurement of average flow (e.g., low-pass filtered flow) or an instantaneous measurement of flow from the flow transducer. This measurement of flow can be the total flow Qt.

[0198] In some implementations, the above dynamic pressure drop parameter resulting from subtracting the second pressure drop parameter from the first pressure drop parameter can be characteristic of the pressure drop from the pressure generator (e.g., a pressure sensor included therein) to the patient interface.

[0199] In some implementations of the process in 13040, the dynamic pressure drop parameter ΔPd d-マスク may be utilized within the controller to control the pressure within the patient interface, such as, for example, compensating for pressure swings or achieving a target pressure control. In some such control methods, which may include a closed-loop controller, the control may include subtracting a dynamic pressure drop parameter derived as a characteristic of the pressure drop from the pressure generator to the patient interface from a target therapy force parameter (e.g., a therapy pressure Pt) and comparing the result of the subtraction to a measurement of pressure from a pressure transducer. Alternatively, in some such control methods, which may include a closed-loop controller, the control may include adding the derived pressure drop parameter (characteristic of the pressure drop from the pressure generator to the patient interface) to a measurement of pressure from a pressure transducer and comparing the result of the addition to a target therapy pressure parameter (e.g., the therapy parameter is a therapy pressure Pt). Other examples of such dynamically derived pressure drop based control, such as control based on the patient interface pressure Pm, may involve the decision to use such dynamically derived pressure drop and may be considered in connection with additional disclosures herein. For example, in some such control methods, which may include a closed-loop controller, the control may include adding a dynamically derived pressure drop parameter (characteristic of the pressure drop from the pressure generator to the patient interface) to a target therapy pressure parameter and / or comparing the result of the addition with a measurement of the device pressure from a pressure transducer and controlling one or more blower drive parameters based on the comparison, or using the result of the addition to control one or more of the blower drive parameters.

[0200] In some examples of the present technology, the patient interface device may be designed to generate a specific function relating therapy pressure to flow rate, unlike other typical components in the system, e.g., non-quadratic, such as valve-like devices, which may be designed, for example, as a valve-like device that generates a step change in flow rate at the intersection of a therapy pressure threshold when the valve is open or closed. In this case, by determining the device sensor pressure at which the characteristic flow rate appears at the mask, the system can estimate the mask pressure associated with the characteristic vent, and then determine the pressure drop between the sensor and interface at the characteristic pressure as the difference between the sensor pressure and the mask pressure.

[0201] 5.5.3.2.2 Interface Pressure Estimation In one implementation of the present technology, the interface pressure estimation algorithm 4312 receives as input a signal from a pressure sensor 4272 representing the pressure in the pneumatic path near the pneumatic block outlet (device pressure Pd), receives a signal from a flow sensor 4274 representing the flow rate of airflow leaving the RPT device 4000 (device flow Qd), and provides as output to the patient interface 3000 an estimated pressure Pm that the system can consider to be the actual mask therapy pressure.

[0202] In one implementation, the interface pressure estimation algorithm 4312 first calculates the total flow Qd as the device flow Qt plus any supplemental gas 4180. The interface pressure estimation algorithm 4312 then uses the pressure drop characteristic ΔP(Q) of the air circuit 4170 or a dynamically determined pressure drop ΔPd to the patient interface as a function of the measured flow or total flow Qt. d-マスク Using this, equation (1) is applied to estimate the interface pressure Pm as the device pressure Pd minus the air circuit pressure drop ΔP at the total flow rate Qt.

[0203] Optionally, such an estimate can be used by a controller thereof to adjust an operating parameter(s) of the RPT device based on the estimate. For example, a flow or pressure therapy control parameter, such as the operation of a blower, can be adjusted based on the estimate. Optionally, this adjusted control parameter can then be applied by the RPT device to operate the blower to provide any of the respiratory therapies described herein based on the adjusted control parameter.

[0204] 5.5.3.2.3 Ventilation flow estimation In one implementation of the present technology, a ventilation flow estimation algorithm 4314 takes as input the estimated pressure Pm in the patient interface 3000 from the interface pressure estimation algorithm 4312 and estimates the air ventilation flow Qv from the ventilation 3400 in the patient interface 3000. The relationship between the ventilation flow Qv and the interface pressure Pm of the particular vent 3400 in use is modeled by the ventilation characteristic f in equation (2), which the system characterization algorithm 4305 can provide based on knowledge of the patient interface 3000 type in use.

[0205] Optionally, such an estimate can be used by a controller thereof to adjust an operating parameter(s) of the RPT device based on the estimate. For example, a flow or pressure therapy control parameter, such as the operation of a blower, can be adjusted based on the estimate. Optionally, this adjusted control parameter can then be applied by the RPT device to operate the blower to provide any of the respiratory therapies described herein based on the adjusted control parameter.

[0206] 5.5.3.2.4 Leak flow rate estimation In one implementation of the present technology, the leak flow estimation algorithm 4316 receives as input the total flow Qt from the interface pressure estimation algorithm 4312 and the ventilation flow Qv from the ventilation flow estimation algorithm 4314 and provides as output an estimate of the leak flow Ql.

[0207] In one implementation, the leak flow estimation algorithm 4316 estimates the leak flow Ql by calculating a filtered version (e.g., a low-pass filtered version) of the non-ventilation flow (equal to the difference between the total flow Qt from the ventilation flow estimation algorithm 4314 and the ventilation flow Qv). The time constant of the low-pass filter is long enough to include several respiratory cycles.

[0208] In one implementation, the leak flow estimation algorithm 4316 receives as input the total flow Qt, ventilation flow Qv, and estimated pressure Pm in the patient interface 3000 from the interface pressure estimation algorithm 4312, calculates the leak conductance, and provides as output the leak flow Ql by determining that the leak flow Ql is a function of the leak conductance and the interface pressure Pm. The leak conductance can be calculated as the quotient of the low pass filter non-ventilation flow and the square root of the low pass filter interface pressure Pm, where the low pass filter time constant has a value long enough to include several respiratory cycles. The leak flow Ql can be estimated as the product of the leak conductance and a function (e.g., the square root) of the interface pressure Pm.

[0209] In one implementation, the leak flow estimation algorithm 4316 receives the total flow Qt and the device pressure Pd as inputs and provides an estimate of the leak flow Ql as output. Figure 12 includes a flow diagram illustrating a method 12000 for estimating the leak flow Ql according to this implementation. The method 12000 can be used to implement the leak flow estimation algorithm 4316 in one implementation of the present technology.

[0210] The method 12000 applies a filter, such as a low pass filter having a time constant of a number of respiratory cycles, to the device pressure Pd to obtain a filtered device pressure Pd.

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[0211] The next step 12020 is to calculate the current filtered device pressure using pressure-flow curve parameters or a lookup table provided by the system characterization algorithm 4305.

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[0212] Next, in step 12030, the filtered total flow rate is

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[0213] Optionally, such an estimate can be used to generate an output. The output can take a variety of forms. In one form, an operating parameter(s) of the RPT device may be adjusted by its controller based on the estimate. For example, a flow or pressure therapy control parameter, such as the operation of a blower, can be adjusted based on the estimate. Optionally, this adjusted control parameter can then be applied by the RPT device to operate the blower to provide any respiratory therapy described herein based on the adjusted control parameter. Alternatively, the output can include generating a message (e.g., notification of a leak or a suggestion of a particular action to be taken) and sending the message to a user or a third party, sending data to a remote server, etc.

[0214] 5.5.3.2.5 Respiratory flow estimation In one implementation of the present technology, the respiratory flow estimation algorithm 4318 receives the total flow Qt, the ventilation flow Qv and the leak flow Ql as inputs and estimates the respiratory flow Qr by subtracting the ventilation flow Qv and the leak flow Ql from the total flow Qt.

[0215] Accurate knowledge of the therapy system pressure-flow characteristic curve provided by the therapy system characterization algorithm 4305, coupled with accurate estimation of leak flow, ventilation flow and respiratory flow by the algorithms of the pre-processing module 4310, proves beneficial to the effectiveness of respiratory therapy. The therapy engine module 4320 particularly benefits from an accurate estimation of respiratory flow Qr.

[0216] For example, using such an estimate, an operating parameter(s) of the RPT device may be adjusted by a controller of the RPT device based on the estimate. For example, a flow or pressure therapy control parameter, such as the operation of a blower, may be adjusted based on the estimate. Optionally, this adjusted control parameter may then be applied by the RPT device to operate the blower to provide any of the respiratory therapies described herein based on the adjusted control parameter.

[0217] 5.5.3.3 Therapy Engine Module In one form of the present technology, the therapy engine module 4320 receives as inputs one or more of the pressure Pm in the patient interface 3000 and the air breathing flow Qr to the patient and provides one or more therapy parameters as outputs.

[0218] In one form of the present technology, the therapy parameter is a treatment pressure, Pt.

[0219] In one form of the present technology, the therapy parameters are one or more of: amplitude of pressure fluctuations, base pressure, and target ventilation.

[0220] In various forms, the therapy engine module 4320 includes one or more algorithms for phase determination 4321, waveform determination 4322, ventilation determination 4323, inspiratory flow limitation determination 4324, apnea / hypopnea determination 4325, snoring determination 4326, airway patency determination 4327, target ventilation determination 4328, and therapy parameter determination 4329.

[0221] 5.5.3.3.1 Phase determination In one form of the present technology, the RPT device 4000 does not determine phase.

[0222] In one form of the present technology, the phase determination algorithm 4321 receives as an input a signal representative of respiratory flow Qr and provides as an output the phase Φ of the patient's 1000 current respiratory cycle.

[0223] In some forms, referred to as discrete phase determination, the phase output Φ is a discrete variable. One implementation of discrete phase determination provides a binary phase output Φ with a value of inspiration or expiration, e.g., a value represented by 0 and 0.5 revolutions, respectively, upon detecting the start of spontaneous inspiration and expiration, respectively. The "trigger" and "loop" RPT device 4000 can perform discrete phase determination efficiently because the trigger and loop points are the moments when the phase changes from expiration to inspiration and from inspiration to expiration, respectively. In one implementation of binary phase determination, if the respiratory flow Qr has a value above a positive threshold, the phase output Φ is determined to a discrete value of 0 (thus "triggers" the RPT device 4000), and if the respiratory flow Qr has a value more negative than a negative threshold, the phase output is determined to a discrete value of 0.5 revolutions (thus "cycles" the RPT device 4000). The inspiration time Ti and expiration time Te can be estimated as typical values ​​for many respiratory cycles of the time spent in phase Φ equal to 0 (representing inspiration) and 0.5 (representing expiration), respectively.

[0224] Another implementation of the discrete phase determination provides a ternary phase output Φ having one of the following values: inspiration, inspiration pause, expiration.

[0225] In other forms, called continuous phase determination, the phase output Φ is a continuous variable, such as 0 to 1 revolution or 0 to 2π radian change. An RPT device 4000 with continuous phase determination can trigger and loop when the continuous phase reaches 0 revolutions or 0.5 revolutions, respectively. In one implementation of continuous phase determination, the phase Φ is first discretely estimated from the respiratory flow Qr described above, as well as the inspiration time Ti and expiration time Te. The continuous phase Φ at any time can be half the percentage of the inspiration time Ti that has elapsed since the previous trigger time, or half the percentage of the expiration time Te that has elapsed since the previous cycle time, plus 0.5 revolutions (whichever is closer).

[0226] 5.5.3.3.2 Waveform determination In one form of the present technology, the therapy parameter determination algorithm 4329 provides a nearly constant therapy pressure throughout the patient's respiratory cycle.

[0227] In another form of the present technology, the therapy control module 4330 controls the pressure generator 4140 to provide a therapy pressure Pt that varies as a function of the phase Φ of the patient's respiratory cycle according to a waveform template Π(Φ).

[0228] In one form of the present technology, the waveform determination algorithm 4322 provides a value within the range [0,1] on the defined domain of phase values ​​Φ provided by the phase determination algorithm 4321 for a waveform template Π(Φ) used by the therapy parameter determination algorithm 4329.

[0229] In one form, applied to discrete or continuous value phases, the waveform template Π(Φ) is a square wave template with a value of 1 for phase values ​​less than 0.5 revolutions and a value of 0 for phase values ​​greater than or equal to 0.5 revolutions. In a form suitable for continuous value phases, the waveform template Π(Φ) is based on two smoothly curved sections, a smoothly curved section (e.g., a rising cosine) where the phase values ​​rise from 0 to 1 up to 0.5 revolutions, and a smoothly bend (e.g., exponentially for phase values ​​greater than 0.5 revolutions) that decays from 1 to 0. In a form suitable for continuous value phases, the waveform template Π(Φ) is based on a square wave, but with phase values ​​smoothly rising from 0 to a "rise time" less than 0.5 revolutions and smoothly falling from 1 to 0 during a "fall time" after 0.5 revolutions, the "fall time" being less than 0.5 revolutions.

[0230] In some forms of the present technology, the waveform determination algorithm 4322 selects a waveform template Π(Φ) from a waveform template library according to the settings of the RPT device. Each waveform template Π(Φ) in the library may be provided as a look-up table of values ​​Π versus phase value Φ. In other forms, the waveform determination algorithm 4322 uses a predefined functional form (which may be parameterized by one or more parameters (e.g., time constant of the exponential curve portion)) to "dynamically" calculate the waveform template Π(Φ). The parameters of the functional form may be predefined or may be dependent on the current state of the patient 1000.

[0231] In some forms of the present technology, applied to a discrete binary phase of inspiration (Φ=0 revolutions) or expiration (Φ=0.5 revolutions), the waveform determination algorithm 4322 calculates a waveform template Π "dynamic" as a function of the discrete phase Φ and time t measured since the most recent trigger instant. In one such form, the waveform determination algorithm 4322 calculates the waveform template Π(Φ,t) in two parts: inspiration and expiration.

number

[0232] Here, Π i (t), and Π e (t) is the inhalation-exhalation portion of the waveform template Π(Φ,t). In one such configuration, i (t) is a smooth rise from 0 to 1 parameterized by the rise time, and the expiratory portion of the waveform template, Π e (t) is a smooth rise from 1 to 0 parameterized by the rise time.

[0233] 5.5.3.3.3 Determining Inspiratory Flow Limitations In one form of the present technology, the central controller 4230 executes an inspiratory flow limitation determination algorithm 4324 to determine the degree of inspiratory flow limitation.

[0234] In one form, the inspiration flow limitation determination algorithm 4324 receives as an input the inspiration flow signal Qr and provides as an output a measure of the extent to which the inspiration portion of the breath exhibits inspiration flow limitation.

[0235] In one form of the technology, the inspiration portion of each breath is identified by a zero-crossing detector. A number of equally spaced points (e.g., 65) representative of each time point are interpolated along the inspiratory flow-time curve of each breath with an interpolator. The curve described by the points is then scaled with a scalar to be of uniform length (duration / cycle) and uniform area to eliminate the effects of changes in respiratory rate and depth. The scaled breaths are then compared in a comparator to a pre-stored template representing a normal open breath, similar to the inspiration portion of the breath shown in FIG. 6A. Breaths (coughs, sighs, swallows, hiccups, etc.) that deviate during inspiration from this template by more than a specified threshold (usually one scale unit) are determined by a test element and rejected. For data that is not rejected, a running average of the first such scaled points of the first few inspiratory vents is calculated by the central controller 4230. This is repeated with the second point, etc. for the same inspiration event. Thus, for example, 65 scaled data points are generated by the central controller 4230 to represent a moving average of the first few inlet vents (e.g., 3 vents). The moving average of the (e.g., 65) points of successive updates is referred to hereinafter as the "scaled flow rate" and defined as Qs(t). Alternatively, instead of a moving average, a single inlet vent can be utilized.

[0236] From the scaled flow rates, two shape factors associated with determining partial occlusion can be calculated.

[0237] A shape factor of 1 is the ratio of the average of the middle (e.g., 32) scaled flow points to the average of the total (e.g., 65) scaled flow points. If this ratio exceeds 1, the breath is considered normal. If the ratio is less than or equal to 1, the breath is considered obstructed. A ratio of approximately 1.17 is used as the threshold between partial obstruction and unobstructed breaths, and is equivalent to a degree of obstruction that allows adequate oxygenation to be maintained in a typical patient.

[0238] The shape factor 2 is calculated as the root mean square deviation from unity scaling flow and is taken to be above a midpoint (e.g., 32). A root mean square deviation of about 0.2 units is considered normal. A root mean square deviation of zero is considered to be a completely flow-limited breath. The closer the root mean square deviation is to zero, the more flow-limited the breath is.

[0239] Shape factors 1 and 2 may be used alternatively or in combination. In other forms of the present technology, the number of sampling points, breathing points, and midpoints may be different from those described above. Also, the thresholds may be different from those described.

[0240] 5.5.3.3.4 Determination of apnea and hypopnea In one form of the present technology, the central controller 4230 executes an apnea / hypopnea determination algorithm 4325 to determine the presence of apnea and / or hypopnea.

[0241] In one form, the apnea / hypopnea decision algorithm 4325 receives as an input the respiratory flow signal Qr and provides as an output a flag indicating that an apnea or hypopnea has been detected.

[0242] In one form, apnea is detected when a function of respiratory flow Qr falls below a flow threshold for a predetermined period of time. The function can be a peak flow, a relative short-term average flow, or a flow intermediate the relative short-term average and peak flow, e.g., RMS flow. The flow threshold can be a relatively long-term measure of flow.

[0243] In one embodiment, hypopnea is detected when a function of respiratory flow Qr falls below a second flow threshold for a predetermined period of time. The function may determine a peak flow, a relative short-term average flow, or a flow intermediate the relative short-term average and peak flow, e.g., RMS flow. The second flow threshold may be a relatively long-term measure of flow. The second flow threshold is greater than the flow threshold for detecting apnea.

[0244] 5.5.3.3.5 Snoring determination In one form of the present technology, the central controller 4230 executes one or more snore determination algorithms 4326 to determine the degree of snoring.

[0245] In one form, the snore determination algorithm 4326 receives as an input the respiratory flow signal Qr and provides as an output a measure of the degree of the presence of snoring.

[0246] The snore determination algorithm 4326 may include determining the strength of the flow signal in the range of 30-300 Hz. Additionally, the snore determination algorithm 4326 may include filtering the respiratory flow signal Qr to reduce background noise, for example the sound of air flow in the system from a blower.

[0247] 5.5.3.3.6 Determination of airway patency In one form of the present technology, the central controller 4230 executes one or more airway patency determination algorithms 4327 to determine the degree of patency of the airway.

[0248] In one form, the airway patency determination algorithm 4327 receives as input the respiratory flow signal Qr and determines the power of the signal in the frequency ranges of about 0.75 Hz and about 3 Hz. The appearance of peaks in this frequency range indicates an open airway. The absence of peaks is considered to indicate airway closure.

[0249] In one form, the frequency range for which the peak is sought is the frequency of a small forced oscillation in the treatment pressure Pt. In one implementation, the forced oscillation has a frequency of 2 Hz and an amplitude of approximately 1 cmH2O.

[0250] In one form, the airway patency determination algorithm 4327 receives as input the respiratory flow signal Qr and determines the presence or absence of a cardiogenic signal, the absence of which is considered an indication of airway obstruction.

[0251] 5.5.3.3.7 Determination of Therapy Parameters In some forms of the present technology, the central controller 4230 executes one or more therapy parameter determination algorithms 4329 to determine one or more therapy parameters using values ​​returned by one or more other algorithms in the therapy engine module 4320.

[0252] In one form of the present technology, the therapy parameter is the instantaneous therapy pressure Pt. In one implementation of this form, the therapy parameter determination algorithm 4329 determines the therapy pressure Pt using the formula:

number

[0253] Where: A is the amplitude, Π(Φ,t) is the waveform template value (range 0 to 1) at the current value of the phase Φ and time t, P0 is the base pressure.

[0254] If the waveform determination algorithm 4322 provides the waveform template Π(Φ,t) as a lookup table of values ​​Π indexed by the phase Φ, the therapy parameter determination algorithm 4329 applies equation (1) by locating the lookup table entry closest to the current value Φ of the phase returned by the phase determination algorithm 4321, or by interpolating between two entries that intersect the current value Φ of the phase. The therapy parameter determination algorithm 4329 may set the values ​​of amplitude A and base pressure P0 depending on the selected respiratory pressure therapy mode as follows:

[0255] 5.5.3.4 Therapy Control Module A therapy control module 4330 according to one aspect of the present technology receives therapy parameters as input from a therapy parameter determination algorithm 4329 of the therapy engine module 4320 and controls the pressure generator 4140 to deliver airflow in accordance with the therapy parameters.

[0256] In one form of the present technology, the therapy parameter is a therapy pressure Pt, and the therapy control module 4330 controls the pressure generator 4140 to deliver an airflow such that the interface pressure Pm at the patient interface 3000 is equal to the therapy pressure Pt.

[0257] 5.5.3.5 Detecting Fault Conditions In one form of the present technology, the central controller 4230 executes one or more methods 4340 to detect a fault condition. The fault condition detected by the one or more methods 4340 may include at least one of the following: Power failure (power off or insufficient power) Transducer Fault Detection Inability to detect the presence of parts Operating parameters outside the recommended range (pressure, flow, temperature, PaO2, etc.) The test alarm must not produce a detectable alarm signal.

[0258] When a fault condition is detected, the corresponding algorithm 4340 signals the presence of a fault by one or more of the following signals: Initiate audio, visual and / or dynamic (e.g. vibration) alarms Sending messages to external devices Incident Recording

[0259] 5.6 Humidifier 5.6.1 Humidifier Overview In one form of the present technology, a humidifier 5000 (e.g., as shown in FIG. 5A) is provided to vary the absolute humidity of the air or gas delivered to the patient relative to the surrounding air. Typically, the humidifier 5000 is used to increase the absolute humidity and raise the temperature of the air stream (relative to the surrounding air) before it is delivered to the patient's airways.

[0260] The humidifier 5000 may include a humidifier reservoir 5110, a humidifier inlet 5002 that receives an air flow, and a humidifier outlet 5004 that delivers a humidified air flow of air. In some forms, the inlet and outlet of the humidifier reservoir 5110 can be the humidifier inlet 5002 and the humidifier outlet 5004, respectively, as shown in Figures 5A and 5B. The humidifier 5000 may also include a humidifier base 5006 that is fitted to receive the humidifier reservoir 5110 and may include a heating element 5240.

[0261] 5.7 Respiratory waveform FIG. 6A shows a typical breathing waveform model of a sleeping human. The horizontal axis is time and the vertical axis is respiratory flow. Although parameter values ​​can vary, a typical breath can have approximate values ​​of ventilation Vt 0.5 L, inspiration time Ti 1.6 s, peak inspiratory flow Q peak 0.4 L / s, expiration time Te 2.4 s, peak expiratory flow Q peak -0.5 L / s. The total time of the breath Ttot is about 4 seconds. A person typically breathes at about 15 breaths per minute (BPM) with a ventilation Vent of about 7.5 liters per minute. A typical duty ratio, Ti to Ttot, is about 40%.

[0262] Figure 6B shows selected polysomnography channels (pulse oximetry, flow, thoracic motion, abdominal motion) of a patient in non-REM sleep, breathing normally for approximately 90 seconds with approximately 34 breaths, being treated with auto-PAP therapy, with an interface pressure of approximately cmH2O. The top channel displays pulse oxygen saturation (oxygen saturation or SpO2), with the scale ranging from 90 to 99% saturation vertically. During the period shown, the patient maintained a saturation of approximately 95%. The second channel shows quantitative respiratory airflow, with the scale ranging from -1 to +1 LPS vertically, with inspiration being positive. Thoracic and abdominal motion are displayed in the third and fourth channels.

[0263] Figure 6C shows the polysomnography of the patient before treatment. From top to bottom there are 11 signal channels with a horizontal span of 6 minutes. The top two channels are EEG (electroencephalogram), each from a different scalp location. The periodic spikes in the second EEG represent cortical arousal and related activity. The third channel pointing downwards is the submental electromyogram (electromyogram). The increase in activity around arousal represents recruitment of the genioglossus muscle. The fourth and fifth channels are EOG (electrooculogram). The sixth channel is the electrocardiogram. The seventh channel shows pulse oximetry (SpO2) with repeated desaturations from approximately 90% to below 70%. The eighth channel is respiratory airflow using a nasal cannula connected to a differential pressure sensor. Repeated apneas of 25 to 35 seconds were alternated with bursts of recovery breathing of 10 to 15 seconds, which coincided with EEG arousals and increased EMG activity. The ninth channel shows thoracic movement and the tenth channel shows abdominal movement. During apnea that causes arousal, the abdomen shows gradually increasing movement. Both become messy during arousal due to the large body movements during recovery hyperpnea. Therefore, the apnea is obstructive and severe. The lowest channel is posture, which shows no change in this example.

[0264] FIG. 6D shows patient flow data as the patient experiences a series of total obstructive apneas. The duration of the recording is approximately 160 seconds. Flow rates range from approximately +1 L / sec to approximately -1.5 L / sec. Each apnea lasts approximately 10-15 seconds.

[0265] 5.8 Respiratory Therapy Mode The disclosed respiratory therapy system is capable of implementing a variety of respiratory therapy modes.

[0266] 5.8.1 CPAP therapy In some implementations of respiratory pressure therapy, the central controller 4230 sets the treatment pressure Pt according to the treatment pressure equation (1) as part of the therapy parameter determination algorithm 4329. In one such implementation, the amplitude A is zero as well, and therefore, in the entire respiratory cycle, the treatment pressure Pt (representing the target value to be achieved at the present time by the interface pressure Pm) is the same as the base pressure P0. Such implementations are often placed under the heading of CPAP therapy. In such implementations, the therapy engine module 4320 does not need to determine the phase Φ or the waveform template Π(Φ).

[0267] In CPAP therapy, the base pressure P0 may be a hard-coded constant value or may be a constant value manually entered into the RPT device 4000. Alternatively, the central controller 4230 may iteratively calculate the base pressure P0 as a function of indicators or measurements of sleep disordered breathing, such as one or more of flow limitation, apnea, hypopnea, patency, and snoring, returned by corresponding algorithms in the therapy engine module 4320. This alternative therapy may be referred to as APAP therapy.

[0268] FIG. 4E is a flow chart illustrating a method 4500 executed by the central controller 4230 to continuously calculate the base pressure P0 as part of the APAP therapy implementation of the therapy parameter determination algorithm 4329 when the pressure support A is also zero.

[0269] The method 4500 begins at step 4520 where the central controller 4230 compares the measured presence or absence of apnea / hypopnea to a first threshold to determine whether the measured presence or absence of apnea / hypopnea exceeds the first threshold for a predetermined time period indicating that apnea / hypopnea is occurring. If so, the method 4500 proceeds to step 4540, otherwise the method 4500 proceeds to step 4530. In step 4540, the central controller 4230 compares the measured airway patency to a second threshold. If the measured airway patency exceeds the second threshold indicating a patent airway, the detected apnea / hypopnea is deemed to be central and the method 4500 proceeds to step 4560, otherwise the apnea / hypopnea is deemed to be obstructive and the method 4500 proceeds to step 4550.

[0270] In step 4530, the central controller 4230 compares the measured flow limitation to a third threshold value. If the measured flow limitation exceeds the third threshold value, indicating that the inspiratory flow is limited, the method 4500 proceeds to step 4550; otherwise, the method 4500 proceeds to step 4560.

[0271] In step 4550, the central controller 4230 increases the base pressure P0 by a predetermined pressure increment ΔP as long as the therapeutic pressure Pt does not exceed the maximum therapeutic pressure Pmax. In one implementation, the predetermined pressure increment ΔP and the maximum therapeutic pressure Pmax are 1 cmH2O and 25 cmH2O, respectively. In other implementations, the pressure increment ΔP can be lowered to 0.1 cmH2O and 3 cmH2O, or to 0.5 cmH2O and 2 cmH2O. In other implementations, the maximum therapeutic pressure Pmax can be lowered to 15 cmH2O, 35 cmH2O, or 20 cmH2O, 30 cmH2O, and then the method 4500 returns to step 4520.

[0272] In step 4560, the central controller 4230 reduces the base pressure Pmin, provided that the reduced base pressure P0 does not fall below the minimum treatment pressure P0. The method 4500 then returns to step 4520. In one implementation, the amount of reduction is proportional to the value, such that the reduction of P0 to the minimum therapeutic pressure Pmin for P0-Pmin is exponential without a detected vent. In one implementation, the proportionality constant is set such that the time constant τ of the exponential reduction of P0 is 60 minutes and the minimum therapeutic pressure Pmin is 4 cmH2O. In other implementations, the time constant τ can be less than 1 minute, less than 300 minutes, or less than 5 minutes, less than 180 minutes. In other implementations, the minimum therapeutic pressure Pmin can be as low as 0 cmH2O and as low as 8 cmH2O, or as low as 2 cmH2O and as low as 6 cmH2O. Alternatively, the decrement of P0 can be predetermined such that, without a detected ventilation outlet, the reduction of P0 to the minimum therapeutic pressure Pmin is linear.

[0273] 5.8.2 Bilevel therapy In other implementations of such a form of the present technology, the value of the amplitude A in equation (1) may be positive. This implementation is called bilevel therapy because when using equation (1) with a positive amplitude A to determine the therapeutic pressure Pt, the therapy parameter determination algorithm 4329 oscillates the therapeutic pressure Pt between two values ​​or levels in synchronization with the spontaneous breathing efforts of the patient 1000. That is, based on the above exemplary waveform template Π(Φ,t), the therapy parameter determination algorithm 4329 increases the therapeutic pressure Pt to P0+A (called IPAP) at the start of inspiration or during inspiration, and decreases the therapeutic pressure Pt to the base pressure P0 (called EPAP) at the start of expiration or during expiration.

[0274] In one form of bilevel therapy, IPAP is a therapeutic pressure with the same purpose as the therapeutic pressure in CPAP therapy mode, and EPAP is IPAP minus amplitude A, which has a "small" value (several cmH2O) and is sometimes called expiratory pressure release (EPR). This form is sometimes called EPR CPAP therapy and is often more comfortable than direct CPAP therapy. In CPAP therapy with EPR, one or both of IPAP and EPAP may be constant values ​​that are hard-coded or manually entered into the RPT device 4000. Alternatively, the therapy parameter determination algorithm 4329 may iteratively calculate IPAP and / or EPAP during CPAP with EPR. In this alternative, the therapy parameter determination algorithm 4329 iteratively calculates EPAP and / or IPAP as a function of the sleep disordered breathing indicators or measurements returned from each algorithm in the therapy engine module 4320. This is done similarly to the calculation of base pressure P0 in APAP therapy described above.

[0275] 5.9 Terminology For purposes of this disclosure, in certain aspects of the technology, one or more of the following definitions may apply. In other aspects of the technology, alternative definitions may apply.

[0276] 5.9.1 General Air: In certain forms of the present technology, air is understood to mean atmospheric air, while in other forms of the present technology, air may be understood to mean other combinations of breathable gases, such as oxygen-rich atmospheric air.

[0277] Surrounding: In certain forms of the present technology, the term surroundings is understood as (i) outside the treatment system or patient, and (ii) immediately surrounding the treatment system or patient.

[0278] For example, the humidity surrounding the humidifier may be the humidity of the air surrounding the humidifier, such as the humidity of the room the patient is sleeping in. This ambient humidity may be different from the humidity outside the room the patient is sleeping in.

[0279] In another example, the ambient pressure may be the pressure surrounding the body or adjacent to the exterior of the body.

[0280] In certain embodiments, ambient (e.g., acoustic) noise is considered to be the background noise level in the room the patient is in, as opposed to, for example, noise generated by the RPT device or noise emanating from a mask or patient interface. Ambient noise may originate from outdoor sources.

[0281] Automated positive airway pressure ventilation (APAP) therapy: CPAP therapy in which the therapeutic pressure is automatically adjusted, varying between minimum and maximum values ​​from breath to breath, depending on the presence or absence of signs of an SDB event.

[0282] Continuous Positive Airway Pressure (CPAP) Therapy: Respiratory pressure therapy in which the therapeutic pressure is approximately constant over the patient's respiratory cycle. In some forms, the pressure at the airway inlet is somewhat higher during exhalation and somewhat lower during inhalation. In some forms, the pressure varies during different respiratory cycles of the patient (e.g., increased in response to detection of an indication of partial upper airway obstruction and decreased in the absence of notification of partial upper airway obstruction).

[0283] Flow Rate: The amount (or mass) of air expelled per unit time. Flow rate can refer to an instantaneous quantity. In some cases, references to flow rate are to scalars, that is, to a quantity with only size. In other cases, references to flow rate are to vectors, that is, to a quantity with both magnitude and direction. Flow rate can be represented by the sign of Q. "Flow rate" is sometimes simply called "flow" or "air flow".

[0284] In the example of a patient breathing, the flow rate may be nominally positive for the inhalation portion of the patient's breathing cycle and therefore negative for the exhalation portion of the patient's breathing cycle. The device flow rate Qd is the flow rate of air leaving the RPT device. The total flow rate Qt is the flow rate of air reaching the patient interface via the air circuit, plus any supplemental gas. The ventilation flow rate Qv is the flow rate of air leaving the ventilation port to expel exhaled gases. The leak flow rate Ql is the flow rate leaked from the patient interface system or elsewhere. The respiratory flow rate Qr is the flow rate of air received by the patient's respiratory system.

[0285] Humidifier: A humidifier is understood to mean a humidification device having a physical structure capable of providing a therapeutically beneficial amount of water (H2O) vapor to an air stream to improve a medical respiratory condition of a patient.

[0286] Leak: Unintended airflow. In one example, a leak can occur due to an imperfect seal between the mask and the patient's face. In another example, a leak can occur at a rotating elbow.

[0287] Patient: A person, whether or not they have a respiratory disease.

[0288] Pressure: force per unit area. Pressure is measured in cmH2O, gf / cm 2 1 cmH2O can be expressed in a variety of units, including 1 g-f / cm 2 which is approximately 0.98 hectopascals (1 hectopascal = 100 Pa = 100 N / m 2 = 1 mbar to 0.001 atm). In this specification, pressures are given in units of cmH2O unless otherwise stated.

[0289] The pressure at the patient interface, labeled Pm, and the treatment pressure, labeled Pt, which indicates the target value that the current interface pressure should reach, labeled Pm.

[0290] Respiratory Pressure Therapy (RPT): Delivery of air to the airway entrance, usually at a positive therapeutic pressure relative to the atmosphere.

[0291] Ventilator: a mechanical device that provides pressure support to a patient to complete some or all of the work of breathing.

[0292] 5.9.2 Breathing cycle Apnea: According to some definitions, apnea is said to occur when flow falls below a predefined threshold for a period of time, e.g., 10 seconds. Obstructive apnea is said to occur when some obstruction of the airway prevents air from flowing despite the patient's efforts. Central apnea occurs when apnea is detected due to reduced or absent respiratory effort despite a fluent airway. Mixed apnea occurs when reduced or absent respiratory effort occurs simultaneously with airway obstruction.

[0293] Respiratory rate: the patient's spontaneous breathing rate, usually measured in breaths per minute.

[0294] Duty cycle: The ratio of the inspiration time Ti to the total breathing time Ttot.

[0295] Effort (breathing): The effort made by a spontaneous breather to breathe.

[0296] Expiratory portion of the respiratory cycle: the period from the start of expiratory flow to the start of inspiratory flow.

[0297] Flow limitation: Flow limitation is considered to be a condition in a patient's breathing where an increase in the patient's effort does not result in a corresponding increase in flow. If the flow limitation occurs during the inspiration portion of the breathing cycle, it can be described as inspiratory flow limitation. If the flow limitation occurs during the expiration portion of the breathing cycle, it can be described as expiratory flow limitation.

[0298] Hypopnea: By some definitions, hypopnea is considered a reduction in flow but not a cessation of flow. In one form, hypoventilation occurs when blood flow falls below a threshold rate for a period of time. Central hypopnea occurs when hypopnea is detected due to a reduction in respiratory effort. In one form in adults, hypopnea may be considered when any of the following occur: (i) A 30% decrease in patient breathing for at least 10 seconds and an associated 4% desaturation; or (ii) A reduction in the patient's breathing (but less than 50%) for at least 10 seconds, accompanied by a desaturation or arousal of at least 3%.

[0299] Hyperventilation: An increase in airflow to a higher than normal level.

[0300] Inhalation portion of the respiratory cycle: The time from the start of the inhalation flow to the start of the exhalation flow is the inhalation portion of the respiratory cycle.

[0301] Patency (airway): The degree to which the airway is open, or the extent to which the airway is open. A patent airway is open. Airway patency can be quantified, for example, with a value of 1 being patent and a value of 0 being closed (obstructed).

[0302] Positive end-expiratory pressure (PEEP): The pressure in the lungs above atmosphere that exists at the end of expiration.

[0303] Peak flow rate (Q ピーク ): Maximum flow rate of the inspiratory portion of the respiratory flow waveform.

[0304] Respiratory flow, Patient airflow rate, Respiratory flow rate (Qr): These terms can be understood to refer to the estimation of respiratory flow by an RPT device. In contrast to "actual respiratory flow" or "actual respiratory flow", actual respiratory flow is the actual respiratory flow experienced by the patient, usually expressed in liters per minute.

[0305] Tidal ventilation (Vt): The volume of air inhaled or exhaled when no extra force is required for normal breathing. In principle, the inhalation volume Vi (volume of inhaled air) and the exhalation volume Ve (volume of exhaled air) are equal, so that an individual ventilation Vt can be defined as being equal to either volume. In practice, the tidal ventilation Vt is estimated as some combination, e.g., the average, of the inhalation volume Vi and the exhalation volume Ve.

[0306] (Inspiration) Time (Ti): The duration of the inspiratory portion of the respiratory flow waveform.

[0307] (Expiratory) Time (Te): The duration of the expiratory portion of the respiratory flow waveform.

[0308] (Total) Time (Ttot): The total time from the start of one inspiratory portion of the respiratory flow waveform to the start of the inspiratory portion of the next respiratory flow waveform.

[0309] Typical Recent Ventilation: The ventilation value around which ventilation recent values ​​over a given timescale tend to cluster, i.e., a measure of the central tendency of ventilation recent values.

[0310] Upper Airway Obstruction (UAO): Includes partial and total upper airway obstruction. This may be associated with a flow-limited state in which flow increases slightly or even decreases as the pressure difference across the upper airway increases (Starling resistor action).

[0311] Vent: A measure of the rate at which gas is exchanged by a patient's respiratory system. Measurements of ventilation may include either or both inspiratory and expiratory flows per unit time. When expressed as volume per minute, this amount is commonly referred to as "minute ventilation." Minute ventilation is sometimes expressed simply as volume, understood as volume per minute. 5.10 Other comments

[0312] A portion of the disclosure of this patent document contains material that 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 and Trademark Office patent file or records, but otherwise reserves all copyright rights.

[0313] Unless the context expressly dictates otherwise, where a range of values ​​is given, it is to be understood that the value of the tenth of the lower limit unit between the upper and lower limits of the range, and any other stated value or values ​​within that range, are included in the technology. The upper and lower limits of these intermediate ranges may independently be included in the intermediate ranges, or may be included in the technology subject to any of the limits specifically excluded from that range. Where a range includes one or two limits, ranges excluding one or two of the included limits are also included in the technology.

[0314] Additionally, when one or more values ​​are described herein as being implemented as part of the technology, it should be understood that these values ​​may be approximated unless otherwise noted and may be utilized to any suitable significant figures to the extent that the actual technical implementation may permit or require.

[0315] Unless otherwise defined, all technical and scientific terms used herein shall have the same meaning as commonly understood by those skilled in the art. Any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present technology, but only a limited number of exemplary methods and materials are described herein.

[0316] When a particular material is determined for constructing a part, obvious alternative materials having similar properties may be used as substitutes. Further, unless otherwise specified, any and all of the components described herein are understood to be manufacturable and therefore may be manufactured together or separately.

[0317] It should be noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the" include their complex equivalents unless the context clearly dictates otherwise.

[0318] All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and / or materials that are the subject of such publications. The publications mentioned herein are used solely for their disclosure prior to the filing date of the present application. Nothing contained herein should be construed as an admission that such art is not entitled to antedate such publication by virtue of prior invention. Additionally, the publication dates provided may be different from the actual publication dates which may need to be independently confirmed.

[0319] The terms "comprises" and "comprises" are to be construed as referring to elements, components, or steps in a non-exclusive manner, meaning that the referenced element, component, or step may be present, used, or combined with other elements, components, or steps that are not explicitly referenced.

[0320] The subject terms used in the detailed description are included solely for ease of reference to the reader and are not intended to limit the subject matter found in the disclosure or claims as a whole. The subject terms are not intended to interpret the scope of or limit the claims.

[0321] Although the 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 technology. In some cases, terms and symbols may imply specific details that are not necessary to practice the technology. For example, the terms "first" and "second" may be used, but unless otherwise stated, they are not intended to indicate any order and may be used to distinguish different elements. Furthermore, although process steps in the method may be interpreted or described in a sequence, this order is not required. Those skilled in the art will recognize that such ordering may be modified and / or aspects thereof may be performed simultaneously or synchronously.

[0322] It is therefore to be understood that numerous modifications may be made to the illustrative examples and other arrangements may be designed without departing from the spirit and scope of the technology. [Explanation of symbols]

[0323] 1000 patients 1100 Bed Partner 3000 Patient Interface 3100 Seal forming structure 3200 Plenum Chamber 3300 Structure 3400 Ventilation Vent 3600 Connection Port 3700 Support 4000 RPT Devices 4010 Outer Housing 4012 Upper 4014 parts 4015 Panel(s) 4016 Chassis 4018 Handle 4020 Pneumatic Block 4110 Air Filter 4112 Inlet Air Filter 4114 Outlet Air Filter 4120 Muffler 4122 Inlet muffler 4124 Exit muffler 4140 Pressure Generator 4142 Blower 4144 Motor 4160 Anti-spillback valve 4170 Air Circuit 4180 Refill Gas 4200 Electrical Components 4202 Printed Circuit Board Assembly 4210 Power supply 4220 Input Device 4230 Central Controller 4232 Clock 4240 Therapy Device Controller 4250 protection circuit 4260 Memory 4270 Transducer 4272 Pressure Transducer 4274 Flow Transducer 4276 Motor Speed ​​Transducer 4280 Data Communication Interface 4282 Remote External Communications Network 4284 local external communications network 4286 Remote External Device 4288 local foreign device 4290 output device 4292 Display Driver 4294 Display 4300 Algorithm 4305 System Characterization Algorithms 4310 Pre-processing module 4312 Interface Pressure Estimation Algorithm 4314 Ventilation Flow Estimation Algorithm 4316 Leak flow rate estimation algorithm 4318 Respiratory flow estimation algorithm 4320 Therapy Engine Module 4321 Phase Determination Algorithm 4322 Waveform Determination Algorithm 4323 Ventilation Decision 4324 Inspiratory Flow Limitation Decision Algorithm 4325 Apnea / Hypopnea Decision Algorithm 4326 Snoring Determination Algorithm 4327 Airway Patency Determination Algorithm 4328 Target ventilation determination 4329 Therapy Parameter Decision Algorithm 4330 Therapy Control Module 4340 method 4500 methods 4520 steps 4530 Steps 4540 Steps 4550 steps 4560 steps 5000 humidifier 5002 Humidifier inlet 5004 Humidifier outlet 5006 Humidifier Base 5110 Humidifier Reservoir 5130 Humidifier Reservoir Dock 5240 heating element 7000 Model 8000 Pressure-Flow Curve 8001 Pressure-Flow Curve 9000 curves 9010 Pressure-Flow Curve 9020 Bias 10000 Histogram 10010 Peak 11000 ways 11010 Step 11020 Step 11030 Step 11040 Step 12000 ways 12020 Steps 12020 Steps 12030 steps 13000 ways 13010 Step 13020 Step 13030 Steps 13040 Steps

Claims

1. 1. A respiratory therapy device comprising: a pressure generator for generating an airflow for delivery via a delivery conduit to a patient interface for respiratory therapy of the patient, the patient interface having a vent; a pressure transducer for generating a signal representative of the pressure generated by the pressure generator; a flow transducer for generating a signal representative of the flow rate of the air stream; receiving the pressure signal and the flow signal from the transducer; analyzing the pressure and flow signals to determine a system curve representing the pressure and flow characteristics of a respiratory therapy system including a device, a delivery conduit, and a patient interface; accessing data associated with a component curve representing pressure and flow characteristics of at least one component of the system; deriving a pressure drop parameter that is characteristic of either or both of the pressure drop at the vent of the patient interface and the pressure drop to the patient interface based on the first function that characterizes the system curve and the second function that represents the component curve; a controller that generates an output based on the derived pressure drop parameters; A respiratory therapy device having:

2. The output is storing data indicative of the derived pressure drop parameter on a storage device on the remote server; generating one or more signals to control operation of the pressure generator to adjust attributes of the airflow based on the pressure drop parameter; displaying information indicative of the derived pressure drop parameter on a display of the respiratory therapy device; transmitting information indicative of the derived pressure drop parameter to a remote server; The device according to claim 1 , comprising at least one of:

3. The apparatus of claim 1 , wherein the second function characterizes a component curve representing pressure and flow characteristics of a ventilation port of the patient interface.

4. The apparatus according to any one of claims 1 to 3, wherein the first function is the quadratic function.

5. The apparatus of claim 4 , wherein the first function comprises a look-up table associated with pressure and flow values.

6. The apparatus of claim 3 , wherein the second function comprises a quadratic function.

7. The apparatus of claim 3 , wherein the second function comprises a look-up table associated with pressure and flow values.

8. Apparatus according to any one of claims 1 to 3, wherein the controller is configured to determine the difference between the first function and the second function to derive the pressure drop parameter.

9. 9. The apparatus of claim 8, wherein the difference comprises a difference between a first reference pressure drop parameter characteristic of a pressure drop from the pressure generator to atmosphere through the system and a second reference pressure drop parameter characteristic of a pressure drop from the vent to atmosphere.

10. 10. The apparatus of claim 9, wherein the controller is configured to determine the first reference pressure drop parameter by applying a measurement of flow rate from the flow transducer to the first function.

11. 10. The apparatus of claim 9, wherein the controller is configured to determine the second reference pressure drop parameter by applying a measurement of flow rate from the flow transducer to the second function.

12. 12. The apparatus of claim 11, wherein the controller is configured to subtract the second reference pressure drop parameter from the first reference pressure drop parameter to derive a pressure drop parameter characteristic of the pressure drop from the pressure generator to the patient interface.

13. The controller adding a derived pressure drop parameter characteristic of the pressure drop from the pressure generator to the patient interface to a target therapy pressure parameter; (a) comparing the result of the addition with a measurement of device pressure from the pressure transducer and controlling one or more blower drive parameters based on the comparison; or (b) using the result of the addition to control one or more of the blower drive parameters; subtracting a pressure drop parameter derived as a characteristic of the pressure drop from the pressure generator to the patient interface from the target therapy pressure parameter and comparing the result of this subtraction with the pressure measurement from the pressure transducer; or 3. The device of claim 2, configured to generate one or more signals to control operation of the pressure generator to control the pressure in the patient interface by adding a pressure drop parameter derived as a characteristic of the pressure drop from the pressure generator to the patient interface to a pressure measurement from the pressure transducer and comparing the result of the addition with a target therapy pressure parameter.

14. 14. The device of claim 13, wherein the controller is configured to detect one or more vents for sleep disordered breathing by evaluating one or more of the signals received from the pressure transducer and / or the flow transducer, and to modify the target therapy pressure parameter based on this evaluation.

15. 15. The device of claim 14, wherein the one or more vents include vents from the group consisting of apnea, hypopnea, snoring, and inspiratory flow limitation.

16. 16. The apparatus of any one of claims 1-3 and 13-15, wherein the controller is configured to determine the actual pressure in the patient interface by subtracting (a) a pressure drop parameter characteristic of the pressure drop from the pressure generator to the patient interface, and (b) a pressure drop parameter derived from a measurement of pressure determined from a signal received from the pressure transducer.

17. 16. The device of any one of claims 1 to 3 and 13 to 15, wherein analysis of the pressure and flow signals to determine a curve representative of the pressure and flow characteristics of the system selects a value on the curve that corresponds to therapy use when mask leak is substantially zero.

18. 16. The apparatus of any one of claims 1 to 3 and 13 to 15, wherein the analysis includes determining parameters for optimally fitting a template curve to a plurality of points, each of the points including (a) a pressure value and (b) a flow value at the pressure value.

19. 16. The apparatus of any one of claims 1 to 3 and 13 to 15, wherein the controller is a central controller for the pressure generator.

20. 20. The apparatus of claim 19, wherein the central controller is configured to determine an identification of the patient interface based on the template curve.

21. The curves representing the pressure and flow characteristics of the system are: (a) a pressure value comprising a low-pass filtered version of the measured pressure from the pressure signal; (b) a flow value comprising a low pass filtered version of the measured flow rate from the flow signal at said pressure value.

22. 16. The device of any one of claims 1 to 3 and 13 to 15, wherein the controller is configured to use and analyze the pressure and flow signals generated by the pressure and flow transducers during a therapy session including automatic positive airway pressure (APAP) therapy.

23. 1. A method of operating a respiratory treatment device, the respiratory treatment device having a pressure generator that generates an airflow for delivery through a delivery conduit to a patient interface for respiratory therapy of a patient, the patient interface having a vent; receiving a pressure signal produced by the pressure transducer and representative of the pressure of the airflow at the pressure generator; receiving a flow signal produced by the flow transducer and representative of a flow rate of the air flow; analyzing the pressure and flow signals to determine a system curve representative of the pressure and flow characteristics of a respiratory therapy system comprising the device, the delivery conduit, and the patient interface, and accessing data associated with a component curve representative of the pressure and flow characteristics of at least one component of the system; deriving a pressure drop parameter that is characteristic of either or both of the pressure drop at the vent of the patient interface and the pressure drop to the patient interface based on a first function that characterizes the system curve and a second function that represents the component curve; generating an output based on the derived pressure drop parameters; A method comprising:

24. A processor-readable medium having program instructions for controlling one or more processors to perform a method of operating a respiratory treatment device having a pressure generator that generates an airflow through a delivery conduit to a patient interface for respiratory treatment of the patient, the method comprising: the patient interface having a vent; The method comprises: receiving a pressure signal generated by a pressure transducer and representative of the pressure of the airflow at the pressure generator; receiving a flow signal produced by a flow transducer and representative of a flow rate of the air flow; analyzing the pressure and flow signals to determine a system curve representative of the pressure and flow characteristics of a respiratory therapy system comprising the device, the delivery conduit, and the patient interface, and accessing data associated with a component curve representative of the pressure and flow characteristics of at least one component of the system; deriving a pressure drop parameter that is characteristic of either or both of the pressure drop at the vent of the patient interface and the pressure drop to the patient interface based on a first function that characterizes the system curve and a second function that represents the component curve; providing an output based on the derived pressure drop parameter; Including, A processor-readable medium.

25. The output is storing data indicative of the derived pressure drop parameter on a storage device of the remote server; displaying information indicative of the derived pressure drop parameter on a display of the respiratory therapy device; generating one or more signals to control operation of the pressure generator to adjust attributes of the airflow based on the pressure drop parameter; or 25. The processor-readable medium of claim 24, further comprising transmitting information indicative of the derived pressure drop parameter to a remote server.

26. 25. The processor-readable medium of claim 24, wherein the second function characterizes a component curve representing pressure and flow characteristics of a vent of the patient interface.

27. The processor-readable medium of any one of claims 24 to 26, wherein the first function is a quadratic function.

28. 28. The processor-readable medium of claim 27, wherein the first function comprises a look-up table associated with pressure and flow values.

29. 27. The processor-readable medium of claim 26, wherein the second function comprises a quadratic function.

30. 27. The processor-readable medium of claim 26, wherein the second function comprises a look-up table associated with pressure and flow values.

31. 27. The processor-readable medium of claim 26, wherein deriving the pressure drop parameter comprises determining a difference between the first function and the second function.

32. 32. The processor-readable medium of claim 31 , wherein the difference comprises a difference between a first reference pressure drop parameter characteristic of a pressure drop from the pressure generator to atmosphere through the system and a second reference pressure drop parameter characteristic of a pressure drop from the vent to atmosphere.

33. 33. The processor-readable medium of claim 32, further comprising determining the first reference pressure drop parameter by applying a measurement of flow rate from the flow transducer to the first function.

34. 34. The processor-readable medium of claim 32 or 33, further comprising determining the second reference pressure drop parameter by applying a measurement of flow rate from the flow transducer to the second function.

35. 35. The processor-readable medium of claim 34, further comprising subtracting the second reference pressure drop parameter from the first reference pressure drop parameter to derive a pressure drop parameter characteristic of the pressure drop from the pressure generator to a patient interface.

36. Adding a pressure drop parameter derived as a characteristic of the pressure drop from the pressure generator to the patient interface to the target therapy pressure parameter; (a) comparing the result of the addition with the device pressure from the pressure transducer and controlling one or more blower drive parameters based on the comparison; or (b) using the result of the addition to control one or more of the blower drive parameters; subtracting a pressure drop parameter derived as a characteristic of the pressure drop from the pressure generator to the patient interface from the target therapy pressure parameter and comparing the result of this subtraction with the pressure measurement from the pressure transducer; or 26. The processor-readable medium of claim 25, further comprising the step of generating one or more signals to control operation of the pressure generator to control the pressure in the patient interface by adding a pressure drop parameter derived as a characteristic of the pressure drop from the pressure generator to the patient interface to the pressure measurement from the pressure transducer and comparing the result of the addition with the target therapy pressure parameter.

37. 37. The processor-readable medium of claim 36, further comprising: detecting one or more vents for sleep disordered breathing by evaluating one or more signals received from the pressure transducer and / or the flow transducer; and altering the target therapy pressure parameters based on this evaluation.

38. 38. The processor-readable medium of claim 37, wherein the one or more vents include vents from the group consisting of apnea, hypopnea, snoring, and inspiratory flow limitation.

39. 39. The processor-readable medium of any one of claims 24-26, 29-33, and 36-38, further comprising: determining an actual pressure in the patient interface by subtracting (a) a pressure drop parameter characteristic of pressure drop from the pressure generator to the patient interface from (b) a pressure drop parameter derived from a pressure measurement determined from a signal received from the pressure transducer.

40. 39. The processor-readable medium of any one of claims 24-26, 29-33 and 36-38, wherein analysis of the pressure and flow signals to determine a curve representative of the pressure and flow characteristics of the system selects a value on the curve that corresponds to therapy use when mask leak is substantially zero.

41. 39. The processor-readable medium of any one of claims 24-26, 29-33, and 36-38, wherein the analysis includes determining parameters for optimally fitting a template curve to a plurality of points, each of the points including (a) a pressure value and (b) a flow value at the pressure value.

42. The processor-readable medium of any one of claims 24-26, 29-33 and 36-38, wherein a controller of a pressure generator performs the method.

43. 39. The processor-readable medium of any one of claims 24-26, 29-33 and 36-38, wherein the controller determines an identity of the patient interface based on the template curve.

44. The curves representing the pressure and flow characteristics of the system are: (a) a pressure value comprising a low-pass filtered version of the measured pressure from the pressure signal; (b) a flow value comprising a low-pass filtered version of a measured flow rate from the flow signal at the pressure value.

45. 39. The processor-readable medium of any one of claims 24-26, 29-33, and 36-38, wherein the analysis uses pressure and flow signals generated by the pressure and flow transducers during a therapy session including automatic positive airway pressure (APAP) therapy.

46. 39. The processor-readable medium of any one of claims 24-26, 29-33, and 36-38, wherein the analysis and / or derivation is performed by one or more remote servers configured to communicate with the respiratory treatment device to receive data for analysis and / or derivation from the respiratory treatment device.

47. 47. The processor-readable medium of claim 46, wherein the one or more remote servers are configured to communicate output with the respiratory treatment device, the communicated output including one or more of data based on the analysis and / or derivation, a derived pressure drop parameter, and / or settings for operation of the respiratory treatment device based on the derived pressure drop parameter.

48. 1. A respiratory treatment device comprising: a pressure generator for generating an airflow for delivery via a delivery conduit to a patient interface for respiratory therapy of the patient, the patient interface having a vent; a pressure transducer for generating a signal representative of the pressure of the air flow; a flow transducer for generating a signal representative of the flow rate of said air stream; a controller comprising one or more processors having a processor-readable medium according to any one of claims 23 to 26, 29 to 33 and 36 to 38; A respiratory treatment device comprising:

49. 1. A system for controlling respiratory therapy, comprising: means for supplying a flow of air to the patient interface as a respiratory therapy; means for generating a flow signal representative of the flow rate of said air stream; means for generating a pressure signal representative of the pressure of said air flow; means for analyzing the pressure and flow signals to determine a system curve representative of the pressure and flow characteristics of the system including the delivery conduit and the patient interface; means for deriving a pressure drop parameter that is characteristic of either or both the pressure drop at the vent of the patient interface and the pressure drop to the patient interface based on a first function that characterizes the system curve and a second function that represents a component curve that is indicative of the pressure and flow characteristics of at least one component of the system; means for generating an output based on the pressure drop parameter; A system comprising:

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