Methods and devices for treating hyperarousal disorders

Abstract

Methods and devices provide automated control for a respiratory pressure therapy device (such as a servo ventilator). For example, a controller of a respiratory pressure therapy device can control the application of pressure support ventilation therapy to a patient's airway. The controller can control the respiratory pressure therapy device to automatically titrate the expiratory positive airway pressure (EPAP) of the pressure support ventilation therapy, thereby maintaining the patient's airway patency. The EPAP can be based on a minimum pressure limit as a lower boundary. The controller can control the respiratory pressure therapy device to repeatedly adjust the minimum pressure limit according to events of interest during the automatic titration of the EPAP. Such a set of methods can improve the treatment of patients (such as those suffering from sleep-disordered breathing with hyperarousal symptoms).

Description

[0001] 1 Cross-reference to related applications

[0002] This application claims the benefit of Australian provisional application number 2014904281 filed on 27 October 2014, the entire disclosure of which is incorporated herein by reference.

[0003] 2 STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0004] not applicable

[0005] 3 Names of the parties involved in the joint research and development

[0006] not applicable

[0007] 4. Sequence Listing

[0008] not applicable 5 Technical Background 5.1 Technical Field

[0011] The present technology relates to one or more of the detection, diagnosis, treatment, prevention and improvement of respiratory-related diseases. Specifically, the present technology relates to medical devices or equipment and their uses.

[0012] 5.2 Related technical description

[0013] 5.2.1 Human respiratory system and its diseases

[0014] The body's respiratory system helps in the exchange of gases. The nose and mouth form the entrance to a person's airway.

[0015] The airways consist of a series of branching tubes that become narrower, shorter, and more numerous as they go deeper into the lungs. The main function of the lungs is gas exchange, allowing oxygen to enter the venous blood from the air and to move carbon dioxide out. The trachea is divided into the left and right main bronchi, and the left and right main bronchi are ultimately further divided into terminal bronchioles. The bronchi constitute the conducting airways and do not participate in gas exchange. The airways are further divided into respiratory bronchioles and ultimately into alveoli. Gas exchange occurs in the alveolar region of the lungs, which is called the respiratory zone. See Respiratory Physiology, John B. West, Lippincott Williams & Wilkins, 9th edition, 2011.

[0016] There is a range of respiratory disorders. Some disorders may present with specific events such as apnea, hypopnea and hyperpnea.

[0017] Obstructive sleep apnea (OSA) is a form of sleep disordered breathing (SDB) characterized by episodes of occlusion or obstruction of the upper air passages during sleep. It is caused by an abnormally small upper airway combined with a normal loss of muscle tone in the tongue, soft palate, and posterior oropharyngeal region during sleep. The condition causes patients with this disease to stop breathing for periods of time, usually 30 to 120 seconds, sometimes 200 to 300 times per night. This often leads to excessive daytime sleepiness and can lead to cardiovascular disease and brain damage. The syndrome is a common condition, especially in middle-aged overweight men, although patients may not be aware of the problem. See U.S. Patent 4,944,310 (Sullivan).

[0018] Cheyne-Stokes respiration (CSR) is another form of sleep-disordered breathing. CSR is a condition in which the patient's respiratory controller has rhythmic alternating cycles of increasing and decreasing ventilation (called CSR cycles). CSR is characterized by repeated deoxygenation and reoxygenation of arterial blood. CSR can be harmful due to repeated hypoxia. In some patients, CSR is associated with repeated arousals from sleep, resulting in severe sleep disruption, increased sympathetic activity, and increased afterload. See U.S. Patent 6,532,959 (Berthon-Jones). CSR is a form of periodic breathing.

[0019] Respiratory failure is an umbrella term for respiratory conditions in which the lungs cannot take in enough oxygen or exhale enough CO2 to meet the patient's needs. Respiratory failure can include some or all of the following conditions.

[0020] People with respiratory insufficiency (a form of respiratory failure) may become abnormally short of breath during exercise.

[0021] A range of therapies have been used to treat or improve this condition. In addition, healthy individuals can also take advantage of this therapy to prevent the onset of respiratory symptoms.

[0022] 5.2.1.1 Insomnia

[0023] Insomnia is defined as problems with falling asleep and staying asleep, or non-restorative sleep that lasts for more than one month and results in functional impairment. Two types of insomnia are defined: (i) sleep onset insomnia, which is difficulty falling asleep; and (ii) sleep maintenance insomnia, which is frequent awakenings during the night or early awakenings. Insomnia can be acute, intermittent, or chronic (lasting for more than six months). Chronic insomnia is a common disorder in the general population as well as in various subgroups (such as the elderly, the mentally ill, and shift workers) (prevalence may range from 6% to 18%). The current theory of insomnia is that, for a variety of reasons, insomniacs are in a state of physiological hyperarousal over a 24-hour period, and this hyperarousal leads to sleep disturbances. Insomnia may be a symptom of another condition, a condition in itself, or both. Insomnia that begins as a symptom of another condition (comorbid insomnia) can develop into a condition in itself.

[0024] Insomnia is often associated with psychological disorders. In Krakow's 2010 study, 87% of insomnia patients reported a history of at least one of the following: depression, anxiety, post-traumatic stress disorder (PTSD), panic disorder, schizophrenia, bipolar disorder, obsessive-compulsive disorder (OCD), trauma exposure, or claustrophobia.

[0025] Although subjects may not report excessive sleepiness, many (but not all) studies have shown higher-than-expected rates of concomitant SDB with hyperarousal disorders, particularly chronic insomnia.

[0026] 5.2.2 Therapy

[0027] Continuous positive airway pressure (CPAP) therapy has been used to treat obstructive sleep apnea (OSA). The mechanism of action is that continuous positive airway pressure acts as a pneumatic splint and can prevent upper airway occlusion (such as by pushing the soft palate and tongue forward and away from the posterior oropharyngeal wall). Treatment of OSA by CPAP therapy can be voluntary, so if a patient finds the device used to provide such therapy uncomfortable, difficult to use, expensive, or unsightly, they may choose not to comply with the therapy.

[0028] Non-invasive ventilation (NIV) provides ventilation support to patients through the upper airway to assist the patient's breathing and / or maintain adequate oxygen levels in the body by doing some or all of the work of breathing. Ventilatory support is provided through a non-invasive patient interface. NIV has been used to treat OSA, respiratory failure, and periodic breathing. In some forms, the comfort and effectiveness of these therapies can be improved.

[0029] A large body of evidence suggests that cognitive behavioral therapy (CBT) is an ideal first-line treatment for insomnia, but a shortage of behavioral sleep medicine specialists in sleep medicine centers and the medical community at large limits its use. In contrast, pharmacotherapy for insomnia is well established. Traditional criteria indicate prescription medications for acute, transient, or situational insomnia, and prescribing instructions may recommend nightly use for several weeks or several times a week at longer intervals.

[0030] However, despite continued use of nighttime prescription medications, a significant percentage of insomnia patients may still experience inadequate relief from their symptoms.

[0031] If SDB is suspected to be associated with insomnia, respiratory pressure therapy may be tried. Although there is controversy over whether SDB is a cause or consequence of insomnia, it has been shown that definitively addressing the associated SDB can improve insomnia. By treating SDB to assist the patient in achieving deeper REM sleep, respiratory pressure therapy may also alleviate any psychological complications.

[0032] In particular, CPAP therapy and more recently adaptive servoventilation (ASV) therapy have been proposed for acute and chronic SDB with insomnia. However, tolerance and adherence to conventional respiratory pressure therapy are often low in patients with insomnia. An obvious challenge facing respiratory pressure therapy in the setting of insomnia is that, at least during the initial phase of adaptation, respiratory pressure therapy itself can be a potential source of sleep disturbance both for sleep onset and for deep sleep throughout the night.

[0033] 5.2.3 Treatment system

[0034] Access to respiratory pressure therapy may include diagnostic systems to confirm the underlying condition, titration systems to titrate effective therapy settings, and treatment systems for individuals to use at home.

[0035] The therapy system may include a respiratory pressure therapy device (RPT device), air circuit, humidifier, patient interface, and data management.

[0036] 5.2.3.1 Patient interface

[0037] The patient interface can be used to interface the respiratory device with its user, for example by providing an air flow to the airway entrance. The air flow can be provided to the nose and / or mouth through a mask, to the mouth through a tube, or to the user's trachea through a tracheostomy tube. Depending on the therapy applied, the patient interface can form a seal (e.g., with the patient's facial area) to facilitate the delivery of gas at a pressure that is sufficiently different from the ambient pressure to achieve therapy, such as a positive pressure of about 10 cmH2O. For other forms of therapy (such as the delivery of oxygen), the patient interface may not include a seal sufficient to deliver gas to the airway at a positive pressure of about 10 cmH2O.

[0038] 5.2.3.2 Respiratory Pressure Therapy (RPT) Devices

[0039] One known RPT device for treating sleep disordered breathing is the S9 Sleep Therapy System manufactured by ResMed. Another example of an RPT device is a non-invasive ventilator.

[0040] The RPT device typically includes a pressure generator (such as a motor-driven blower or a compressed gas reservoir) and is configured to supply air flow to the patient's airway. In some cases, the air flow can be supplied to the patient's airway under positive pressure. The outlet of the RPT device is connected to a patient interface such as described above through an air circuit.

[0041] 5.2.3.3 Humidifier

[0042] Delivering an air stream without humidification can result in airway drying. Using a humidifier with an RPT device and a patient interface produces humidified gas that minimizes drying of the nasal mucosa and increases patient airway comfort. Additionally, in colder climates, warm air generally applied to the facial area in and around the patient interface is more comfortable than cold air. A range of artificial humidification devices and systems are known, however, they may not meet the special requirements of medical humidifiers.

[0043] 5.2.4 Diagnostic and monitoring systems

[0044] Diagnosis is the identification of a disease from its signs and symptoms. Diagnosis is often a one-time process, while monitoring the progression of a disease can continue indefinitely. Some diagnostic systems are only suitable for diagnosis, while some can also be used for monitoring.

[0045] Polysomnography (PSG) is a conventional system for diagnosis and prognosis of sleep disorders, and usually includes expert clinical staff who apply and / or interpret both. PSG usually includes placing 15 to 20 contact sensors on a person to record various body signals, such as electroencephalogram (EEG), electrocardiogram (ECG), electrooculogram (EOG), electromyogram (EMG), etc. PSG for sleep apnea includes two nights of observation of clinical patients, one night of simple diagnosis, and the second night of titration of treatment parameters by a clinician. However, although they are suitable for their conventional application in clinical settings, PSG systems are complex and quite expensive, and / or may be uncomfortable or impractical for patients (especially insomniacs) who are trying to sleep at home.

[0046] The differences in the reported incidence of SDB in patients with chronic insomnia may be related to diagnostic approaches, as comorbid SDB in this group of patients with insomnia is challenging to diagnose successfully: conventional scores based on the apnea-hypopnea index (AHI) may not be sensitive to SDB in this group (even under routine polysomnography).

[0047] 6 Technical content

[0048] The present technology is directed to providing medical devices for diagnosing, ameliorating, treating or preventing respiratory conditions with improved one or more of comfort, cost, efficacy, ease of use, and manufacturability.

[0049] The present technology generally relates to devices and methods for diagnosing, ameliorating, treating or preventing hyperarousal disorders.

[0050] Unless otherwise specified, in the following text, the term "insomnia" is used to represent all hyperarousal disorders including insomnia, anxiety disorders, and PTSD.

[0051] One aspect of the present technology includes methods and devices for adapting patients with SDB and insomnia to respiratory pressure therapy through paced breathing. The paced breathing can be combined with biofeedback. This adaptation method and device can also be used as a calming intervention, whether during the daytime, before entering sleep, or during nighttime awakenings.

[0052] Another aspect of the present technology includes methods and devices for effective treatment of insomnia associated with SDB, including pressure support ventilation with adaptive ventilation targets and automatic titration of expiratory pressure. The expiratory pressure of the pressure support ventilation is automatically titrated at a variable minimum pressure limit. During automatic titration, the minimum pressure limit can be repeatedly adjusted based on events of interest. Alternatively, the minimum pressure limit can be repeatedly adjusted based on the increment of expiratory pressure during a previous analysis interval. When the patient is awake, pressure support ventilation therapy can be replaced by adaptive therapy (e.g., paced breathing with biofeedback).

[0053] Another aspect of the present technology includes methods and apparatus for effective treatment of insomnia associated with SDB, including servo-ventilation, wherein a gain value of the servo-ventilation control is varied based on the patient's sleep state.

[0054] Some variations of the present technology relate to methods for determining a minimum pressure limit for the EPAP pressure of a respiratory pressure therapy device, such as for a patient with SDB associated with hyperarousal. The method may include monitoring pressure support ventilation therapy of a respiratory pressure therapy device that automatically titrates the EPAP of the pressure support ventilation therapy to maintain airway patency in the patient. The method may repeatedly include, in a controller, determining an adjusted minimum pressure limit based on an event of interest that occurs during EPAP automatic titration monitoring. Optionally, the method may further include delivering the EPAP so that it is greater than or equal to the adjusted minimum pressure limit.

[0055] Some variations of the present technology may include a method of controlling a respiratory pressure therapy device to treat a patient's SDB associated with hyperarousal disorder. The method may include controlling the application of pressure support ventilation therapy to the patient's airway through the respiratory pressure therapy device. The method may include controlling the respiratory pressure therapy device to automatically titrate the EPAP of the pressure support ventilation therapy to maintain the patient's airway patency so that the EPAP is bounded by a minimum pressure limit. The method may include controlling the respiratory pressure therapy device to repeatedly adjust the minimum pressure limit according to an event of interest during the automatic titration of the EPAP.

[0056] In some variations, the event of interest may be an increment of EPAP, and the repeated adjustment of the minimum pressure limit repeatedly includes: forming a distribution of EPAP values ​​of EPAP increments occurring within an analysis interval, and adjusting the minimum pressure limit based on a statistical analysis of the distribution. The adjustment of the minimum pressure limit may be based on a pattern of the distribution. The analysis interval may be a night of pressure support ventilation therapy with automatic titration of EPAP. The adjustment of the minimum pressure limit may depend on the current value of EPAP. The adjustment of the minimum pressure limit may depend on the number of events of interest occurring within a predetermined interval during the automatic titration of EPAP. If a predetermined number of events of interest occur within a predetermined interval, the adjustment of the minimum pressure limit may include incrementing the minimum pressure limit. The increment of the minimum pressure limit may include increasing the minimum pressure to the current value of EPAP.

[0057] In some variations, the event of interest may be an SDB event. The event of interest may be an increment of EPAP due to automatic titration of EPAP. The method may further include determining a sleep state of the patient in the respiratory pressure therapy device. When determining that the patient is in a deep sleep state, the automatic titration of EPAP may include not reducing EPAP.

[0058] Optionally, pressure support ventilation therapy may be applied depending on the patient's sleep state. When the patient is determined to be in a deep sleep state, the respiratory pressure therapy device may apply pressure support ventilation therapy, and when the patient is determined to be in an awake state, the respiratory pressure therapy device may apply adaptive therapy. The adaptive therapy may be paced breathing. The paced breathing may be combined with biofeedback that matches the temporary breathing rate target of the paced breathing. The biofeedback may be one or more of acoustic and visual forms.

[0059] In some cases, the method may include applying pressure support ventilation therapy via a respiratory pressure therapy device upon receiving a command from the patient. The command may be a manually controlled activation. The command may be a sound uttered by the patient. The command may be a voluntary breathing action of the patient.

[0060] Some variations of the present technology may include a method of controlling a servo-ventilator to treat a patient's SDB with hyperarousal condition. The method may include controlling a servo-ventilator to servo-ventilate the patient using a servo-ventilation control gain value. The method may include determining a sleep state of the patient. The servo-ventilation control gain value may vary based on the determined sleep state. In some cases, the servo-ventilation control gain value may be relatively low when the patient is determined to be awake, and may be relatively high when the patient is determined to be in a deep sleep state.

[0061] Some variations of the present technology may include a method of acclimating a patient to pressure support ventilation therapy. The method may include applying paced breathing to the patient's airway via a respiratory pressure therapy device. The method may include providing biofeedback to the patient, wherein the biofeedback matches a temporary respiratory rate target for the paced breathing.

[0062] In some variations, the biofeedback may be one or more of acoustic and visual forms. The method may include terminating the paced breathing upon receiving a command from the patient. The command may be a manually controlled activation. The command may be a sound uttered by the patient. The command may be a voluntary breathing action of the patient.

[0063] Some variations of the present technology may include a device for treating hyperarousal associated with SDB. The device may include a pressure generator configured to deliver an air flow to a patient's airway at a controllable treatment pressure above atmospheric pressure through a patient interface on an air circuit. The device may include a controller. The controller may be configured to control the treatment pressure of the air flow so as to apply pressure support ventilation therapy to the patient's airway. The controller may be configured to automatically titrate the EPAP of the pressure support ventilation therapy to maintain the patient's airway patency so that the EPAP is bounded below the minimum pressure limit. The controller may be configured to repeatedly adjust the minimum pressure limit according to events of interest during the automatic titration of the EPAP.

[0064] Some variations of the device may include a sensor configured to generate a signal representative of a physiological characteristic of the patient. The controller may be further configured to determine the patient's sleep state from the signal. The device may include a user input device including a manual control. The device may include an audio sensor. The device may include a data communication interface through which the controller is configured to communicate with a local external device. The controller may be configured to control the local external device to provide biofeedback to the patient. The controller may be configured to receive an audio signal from the local external device. The controller may be configured to receive a signal representative of the patient's physiological characteristic from the local external device. The controller may be further configured to determine the patient's sleep state from the signal.

[0065] Some variations of the present technology may include a device for treating hyperarousal associated with SDB. The device may include a pressure generator configured to deliver an air flow to a patient's airway at a controllable therapeutic pressure above atmospheric pressure through a patient interface on an air circuit. The device may include a controller configured to control the therapeutic pressure of the air flow so as to servo-ventilate the patient using a servo-ventilation control gain value. The controller may be configured to determine a sleep state of the patient. The servo-ventilation control gain value may vary based on the determined sleep state.

[0066] Some variations of the present technology may include a device. The device may include a pressure generator configured to deliver an air flow to a patient's airway at a controllable therapeutic pressure above atmospheric pressure through a patient interface on an air circuit. The device may include a controller configured to control the therapeutic pressure of the air flow so as to apply paced breathing to the patient's airway. The controller may be configured to control the provision of biofeedback to the patient. The biofeedback may be matched to a temporary breathing rate target for paced breathing. The device may include a user input device including a manual control. The controller may be further configured to terminate paced breathing and biofeedback activated by manual control. The device may include an audio sensor. The controller may be further configured to terminate paced breathing and biofeedback when the audio sensor detects a predetermined sound. The device may include a data communication interface, through which the controller may be configured to communicate with a local external device. The controller may be configured to control the local external device to provide biofeedback to the patient. The controller may be further configured to receive an audio signal from the local external device. The controller may be further configured to terminate paced breathing and biofeedback when a predetermined sound in the audio signal is detected.

[0067] The method / system / device / apparatus described herein can provide improved functionality in a processor (such as a processor of a special purpose computer), a respiratory monitor, and / or a respiratory pressure therapy device. In addition, the method / system / device / apparatus can provide improvements in the field of automated management, monitoring, and / or treatment of respiratory disorders (including, for example, SDB with insomnia).

[0068] Of course, some aspects may form sub-aspects of the present technology. Moreover, various sub-aspects and / or aspects may be combined in various ways and also constitute additional aspects or sub-aspects of the present technology.

[0069] Other features of the technology will be apparent from consideration of the information contained in the following detailed description, abstract, drawings, and claims. 7. Description of the drawings

[0071] The present technology is illustrated by way of example and not limitation in the figures of the accompanying drawings in which like reference numerals refer to like elements, including:

[0072] 7.1 Treatment System

[0073] Figure 1 A therapy system is shown including a patient 1000 wearing a patient interface 3000 in the form of a full face mask, receiving a positive pressure air supply from an RPT device 4000. Air from the RPT device 4000 is humidified in a humidifier 5000 and passed along an air circuit 4170 to the patient 1000.

[0074] 7.2 Respiratory system and facial anatomy

[0075] Figure 2 An overview of the human respiratory system including the nasal and oral cavities, larynx, vocal cords, esophagus, trachea, bronchi, lungs, alveolar sacs, heart, and diaphragm is shown.

[0076] 7.3 Patient Interface

[0077] Figure 3 A patient interface in the form of a nasal mask in accordance with one form of the present technology is shown.

[0078] 7.4RPT device

[0079] Figure 4A One form of RPT device according to the present technology is shown.

[0080] Figure 4B Schematic diagram of the pneumatic path of an RPT device according to one form of the present technology. The upstream and downstream directions are indicated.

[0081] Figure 4C is a schematic diagram of the electrical components of an RPT device according to one form of the present technology.

[0082] Figure 4D is a schematic diagram of an algorithm implemented in an RPT device according to one form of the present technology. In this figure, solid arrows indicate the actual information flow (eg, via electronic signals).

[0083] 7.5 Humidifier

[0084] Figure 5 An isometric view of a humidifier according to one form of the present technology is shown.

[0085] 7.6 Respiratory Waveform

[0086] Fig. 6A A typical breathing waveform of a person during sleep is shown.

[0087] Figure 6B A patient's normal breathing during non-REM sleep is shown for approximately ninety seconds.

[0088] Figure 6C Shown is a polysomnogram of the patient before treatment.

[0089] Fig.6D Shown is flow data for a patient while the patient was experiencing a series of total obstructive apneas.

[0090] Fig. 6E The inspiratory portion of a breath is shown scaled when the patient is experiencing low frequency inspiratory snoring.

[0091] Fig. 6F Shown is a zoomed inspiratory portion of a breath when the patient is experiencing an example of a normal or "table-shaped" plateau of inspiratory flow limitation.

[0092] Figure 6G Shown is a zoomed inspiratory portion of a breath where the patient is experiencing an example of "chair" inspiratory flow limitation.

[0093] Figure 6H Shown is a zoomed inspiratory portion of a breath where the patient is experiencing an example of "reverse chair" inspiratory flow limitation.

[0094] Fig.6I Shown is a zoomed inspiratory portion of a breath where the patient is experiencing an example of "M-shaped" inspiratory flow limitation.

[0095] Figure 6J Patient data from a Cheyne-Stokes breathing patient are shown.

[0096] 7.7 Breathing Pressure Therapy Mode

[0097] Figure 7 It is explained in Figure 4A A flow chart of a method for calculating a new value of EPAP in one form of an RPT device.

[0098] 7.8 Pressure waveform

[0099] Figure 8 An exemplary "smooth and comfortable" therapeutic pressure waveform template as a function of phase in accordance with one form of the present technology is illustrated.

[0100] Fig. 9 Contains a histogram of EPAP values ​​as EPAP is incremented during a 60 minute analysis interval of an EPAP automatic titration.

[0101] Fig.10 A control method (such as for an RPT device) is described that adjusts a servo-ventilation control gain value based on a determined sleep state.

[0102] Fig.11 An exemplary method of controlling paced breathing via an RPT device with biofeedback is described.

[0103] 8 Detailed description of technical examples

[0104] Before describing the present technology in further detail, it should be understood that the technology is not limited to the specific examples of possible variations described herein. It should also be understood that the terms used in the present disclosure are only used to describe the specific examples discussed herein, and are not limiting.

[0105] The following description is provided about various examples that can share one or more common features and / or characteristics. It should be understood that one or more characteristics of any one example can be combined with one or more characteristics of another example or other examples. In addition, any single characteristic or combination of characteristics in any example can constitute another example.

[0106] 8.1 Therapy

[0107] In one form, the present technology includes a method of treating insomnia comprising the step of applying positive pressure to an airway entrance of a patient 1000 .

[0108] 8.2 Treatment system

[0109] In one form, the present technology includes an apparatus or device for treating insomnia. The apparatus or device may include an RPT device 4000 for supplying pressurized air to a patient 1000 via an air circuit 4170 to a patient interface 3000 .

[0110] 8.3 Patient Interface

[0111] A non-invasive patient interface 3000 according to one form of the present technology includes the following functional aspects: a seal-forming structure 3100, a plenum chamber 3200, a positioning and stabilizing structure 3300, an exhaust port 3400, a connection port 3600 for connecting to a form of air circuit 4170, and a forehead support 3700. In some forms, the functional aspects may be provided by one or more physical components. In some forms, one physical component may provide one or more functional aspects. In use, the seal-forming structure 3100 is arranged to surround the patient's airway entrance so as to facilitate the supply of positive pressure air to the airway.

[0112] 8.4 RPT device

[0113] An RPT device 4000 according to one form of the present technology includes mechanical and pneumatic components 4100, electrical components 4200, and is configured to execute one or more algorithms 4300. The RPT device has an outer housing 4010 that may be formed in two parts, an upper portion 4012 and a lower portion 4014. In addition, the outer housing 4010 may include one or more plates 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.

[0114] The pneumatic path of the RPT device 4000 may include one or more air path items, such as an inlet air filter 4112, an inlet muffler 4122, a pressure generator 4140 (e.g., a blower 4142) capable of supplying positive pressure air, an outlet muffler 4124, and one or more transducers 4270 (such as a pressure sensor 4272 and a flow sensor 4274).

[0115] One or more air path items may be located within a removable unitary structure referred to as a pneumatic block 4020. The pneumatic block 4020 may be located within the outer housing 4010. In one form, the pneumatic block 4020 is supported by or formed as part of the chassis 4016.

[0116] The RPT device 4000 may have a power source 4210, one or more input devices 4220, a central controller 4230, a therapy device controller 4240, a pressure generator 4140, one or more protection circuits 4250, a memory 4260, a transducer 4270, a data communication interface 4280, and one or more output devices 4290. The electrical components 4200 may be mounted on a single printed circuit board assembly (PCBA) 4202. In alternative forms, the RPT device 4000 may include more than one PCBA 4202.

[0117] 8.4.1 RPT device mechanical and pneumatic components

[0118] The RPT device may include one or more of the following components in an integral unit. In an alternative form, one or more of the following components may be located as respective separate units.

[0119] 8.4.1.1 Air filter

[0120] An RPT device according to one form of the present technology may include one air filter 4110 or multiple air filters 4110.

[0121] In one form, the inlet air filter 4112 is located at the beginning of the pneumatic path upstream of the pressure generator 4140 .

[0122] In one form, an outlet air filter 4114 (eg, an antimicrobial filter) is located between the outlet of the pneumatic block 4020 and the patient interface 3000 .

[0123] 8.4.1.2 Muffler

[0124] An RPT device according to one form of the present technology may include a muffler 4120 or a plurality of mufflers 4120 .

[0125] In one form of the present technology, the inlet muffler 4122 is located in the upstream pneumatic path of the pressure generator 4140 .

[0126] In one form of the present technology, an outlet muffler 4124 is located in the pneumatic path between the pressure generator 4140 and the patient interface 3000 .

[0127] 8.4.1.3 Pressure generator

[0128] In one form of the present technology, the pressure generator 4140 for generating a flow or supply of positive pressure air is a controllable blower 4142. For example, the blower 4142 may include a brushless DC motor 4144 with one or more impellers housed in a volute. The blower is capable of delivering a supply of air (e.g., at a rate of up to about 120 liters / minute, at a positive pressure in the range of about 4 cmH2O to about 20 cmH2O, or in other forms up to about 30 cmH2O). The blower may be as described in any of the following patents or patent applications, the contents of which are incorporated herein in their entirety: U.S. Patent No. 7,866,944; U.S. Patent No. 8,638,014; U.S. Patent No. 8,636,479; and PCT Patent Application Publication No. WO 2013 / 020167.

[0129] The pressure generator 4140 is controlled by the therapy device controller 4240.

[0130] In other forms, the pressure generator 4140 may be a piston driven pump, a pressure regulator connected to a high pressure source (e.g., a compressed air reservoir), or a bellows.

[0131] 8.4.1.4 Transducer

[0132] The transducer may be internal to the RPT device, or external to the RPT device. An external transducer may be located, for example, on or form part of an 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 movement sensor) that transmits or transfers data to the RPT device.

[0133] In one form of the present technology, one or more transducers 4270 are located upstream and / or downstream of the pressure generator 4140. The one or more transducers 4270 may be constructed and arranged to measure a property (such as flow rate, pressure, or temperature) at that point in the pneumatic path.

[0134] In one form of the present technology, one or more transducers 4270 may be located proximate to the patient interface 3000 .

[0135] In one form, the signal from transducer 4270 may be filtered (such as by low pass, high pass, or band pass filtering).

[0136] 8.4.1.4.1 Flow rate sensor

[0137] A flow rate sensor 4274 according to the present technology may be based on a differential pressure transducer (eg, the SDP600 series differential pressure transducer from SENSIRION).

[0138] In one form, a signal representing the flow rate (such as the total flow rate Qt) from the flow rate sensor 4274 is received by the central controller 4230.

[0139] 8.4.1.4.2 Pressure sensor

[0140] A pressure sensor 4272 according to the present technology is positioned in fluid communication with the pneumatic path. An example of a suitable pressure sensor is a transducer from the ASDX series of HONEYWELL. An alternative suitable pressure sensor is a transducer from the NPA series of GENERALELECTRIC.

[0141] In one form, signals from pressure sensor 4272 are received by central controller 4230.

[0142] 8.4.1.4.3 Motor speed transducer

[0143] In one form of the present technology, a motor speed transducer 4276 is used to determine the rotational speed of the motor 4144 and / or blower 4142. A 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, for example, a speed sensor such as a Hall Effect sensor.

[0144] 8.4.1.5 Anti-overflow check valve

[0145] In one form of the present technology, an anti-flood check valve 4160 is located between the humidifier 5000 and the pneumatic block 4020. The anti-flood check valve is constructed and arranged to reduce the risk of water flowing upstream from the humidifier 5000 to the motor 4144, for example.

[0146] 8.4.1.6 Air circuit

[0147] An air circuit 4170 in accordance with one form of the present technology is a conduit or tube constructed and arranged to allow air flow to travel between two components, such as a pneumatic block 4020 and a patient interface 3000 .

[0148] In particular, the air circuit 4170 can be fluidly connected to the pneumatic block outlet and the patient interface. The air circuit can be referred to as an air delivery tube. In some cases there may be separate branches for the inspiratory and expiratory circuits. In other cases a single branch is used.

[0149] 8.4.1.7 Oxygen delivery

[0150] In one form of the present technology, supplemental oxygen 4180 is delivered to one or more points in the pneumatic pathway (such as upstream of the pneumatic block 4020 ), the air circuit 4170 , and / or the patient interface 3000 .

[0151] 8.4.2 RPT device electrical components

[0152] 8.4.2.1 Power supply

[0153] The power source 4210 may be located inside or outside of the outer housing 4010 of the RPT device 4000 .

[0154] In one form of the present technology, the power supply 4210 provides power only to the RPT device 4000. In another form of the present technology, the power supply 4210 provides power to both the RPT device 4000 and the humidifier 5000.

[0155] 8.4.2.2 Input devices

[0156] 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 dials to allow a person to interact with the device. The buttons, switches, or dials may be physical devices or software devices accessible through a touch screen. The buttons, switches, or dials may be physically connected to the external housing 4010 in one form, or may be in another form to communicate wirelessly with a receiver electrically connected to the central controller 4230.

[0157] In one form, input device 4220 may be constructed and arranged to allow a person to select values ​​and / or menu options.

[0158] 8.4.2.3 Central Controller

[0159] In one form of the present technology, the central controller 4230 is one or more processors suitable for controlling the RPT device 4000.

[0160] Suitable processors may include x86 INTEL processors, processors based on ARM Holdings' ARM Cortex-M processors (such as the STM32 series microcontrollers from ST MICROELECTRONIC). In some alternative forms of the present technology, 32-bit RISC CPUs (such as the STR9 series microcontrollers of ST MICROELECTRONICS) or 16-bit RISC CPUs (such as processors of the MSP430 microcontroller series manufactured by TEXAS INSTRUMENTS) may also be suitable.

[0161] In one form of the present technology, the central controller 4230 is a dedicated electronic circuit.

[0162] In one form, the central controller 4230 is an application specific integrated circuit. In another form, the central controller 4230 includes discrete electronic components.

[0163] The central controller 4230 may be configured to receive input signals from one or more transducers 4270 and one or more input devices 4220 .

[0164] The central controller 4230 may be configured to provide output signals to one or more of the output device 4290 , the therapy device controller 4240 , the data communication interface 4280 , and the humidifier 5000 .

[0165] In some forms of the present technology, the central controller 4230 is configured to implement one or more methods described herein (such as one or more algorithms 4300 represented as computer programs 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 remotely located device. For example, the remotely located device may determine control settings for the ventilator or detect breathing-related events by analyzing stored data (such as from any of the sensors described herein).

[0166] 8.4.2.4 Clock

[0167] The RPT device 4000 may include a clock 4232 connected to a central controller 4230 .

[0168] 8.4.2.5 Therapy device controller

[0169] 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.

[0170] 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.

[0171] 8.4.2.6 Protection circuit

[0172] One or more protection circuits 4250 in accordance with the present technology may include electrical protection circuits, temperature and / or pressure safety circuits.

[0173] 8.4.2.7 Memory

[0174] According to one form of the present technology, the RPT device 4000 includes memory 4260, preferably 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.

[0175] The memory 4260 may be located on the PCBA 4202. The memory 4260 may be in the form of an EEPROM or a NAND flash memory.

[0176] Additionally or alternatively, the RPT device 4000 includes memory 4260 in a removable form, such as a memory card made in accordance with the Secure Digital (SD) standard.

[0177] In one form of the present technology, the memory 4260 serves as a non-transitory computer-readable storage medium on which are stored computer program instructions representing one or more of the methods described herein, such as one or more algorithms 4300 .

[0178] 8.4.2.8 Data Communication System

[0179] In a preferred form of the present technology, a data communication interface 4280 is provided and connected to the central controller 4230. The data communication interface 4280 can be connected to a remote external communication network 4282 and / or a local external communication network 4284. The remote external communication network 4282 can be connected to a remote external device 4286. The local external communication network 4284 can be connected to a local external device 4288.

[0180] In one form, the data communications interface 4280 is part of the central controller 4230. In another form, the data communications interface 4280 is separate from the central controller 4230 and may include an integrated circuit or processor.

[0181] In one form, remote external communication network 4282 is the Internet. Data communication interface 4280 may use wired communication (eg, via Ethernet or fiber optics) or wireless protocols (eg, CDMA, GSM, LTE) to connect to the Internet.

[0182] In one form, the local external communications network 4284 utilizes one or more communications standards (such as Bluetooth) or consumer infrared protocols.

[0183] In one form, the remote external device 4286 is one or more computers (e.g., a networked computer cluster). In one form, the remote external device 4286 can be a virtual computer rather than a physical computer. In either case, such a remote external device 4286 can be accessed by appropriately authorized personnel (such as a clinician).

[0184] The local external device 4288 may be a personal computer, a "smartphone", a tablet computer, a "smart watch" or a remote control.

[0185] 8.4.2.9 Output devices including optional display and alarm

[0186] Output devices 4290 according to the present technology may take the form of one or more of visual, audio, and tactile units. The visual display may be a liquid crystal display (LCD) or a light emitting diode (LED) display.

[0187] 8.4.2.9.1 Display Driver

[0188] The display driver 4292 receives characters, symbols, or images to be displayed on the display 4294 as input, and converts them into commands that cause the display 4294 to display the characters, symbols, or images.

[0189] 8.4.2.9.2 Display

[0190] 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 (such as the number "0") into eight logic signals indicating whether the eight corresponding segments are activated to display the particular character or symbol.

[0191] 8.4.3 RPT device algorithm

[0192] 8.4.3.1 Preprocessing Module

[0193] A pre-processing module 4310 according to one form of the present technology receives as input a signal from a transducer 4270 (e.g., a flow sensor 4274 or a pressure sensor 4272) and performs one or more processing steps to calculate one or more output values ​​to be used as input to another module (e.g., a therapy engine module 4320).

[0194] In one form of the present technology, the output values ​​include the interface or mask pressure Pm, the respiratory flow rate Qr, and the unintentional leak flow rate Ql.

[0195] In various forms of the present technology, the pre-processing module 4310 includes one or more of the following algorithms: pressure compensation 4312 , exhaust flow rate estimation 4314 , leakage flow rate estimation 4316 , respiratory flow rate estimation 4318 , and interference detection 4319 .

[0196] 8.4.3.1.1 Pressure compensation

[0197] In one form of the present technology, a pressure compensation algorithm 4312 receives as input a signal representing the pressure in the pneumatic path near the outlet of the pneumatic block. The pressure compensation algorithm 4312 estimates the pressure drop through the air circuit 4170 and provides as output an estimated pressure Pm in the patient interface 3000.

[0198] 8.4.3.1.2 Exhaust flow rate estimation

[0199] In one form of the present technology, the exhaust flow rate estimation algorithm 4314 receives as input an estimated pressure Pm in the patient interface 3000 and estimates an exhaust flow rate Qv of air from the exhaust port 3400 in the patient interface 3000 .

[0200] 8.4.3.1.3 Leakage flow rate estimation

[0201] In one form of the present technology, the leakage flow rate estimation algorithm 4316 receives the total flow rate Qt and the exhaust flow rate Qv as inputs and provides an estimate of the leakage flow rate Ql as output. In one form, the leakage flow rate estimation algorithm estimates the leakage flow rate by calculating the average value of the difference between the total flow rate Qt and the exhaust flow rate Qv over a period long enough to include several breathing cycles (e.g., about 10 seconds).

[0202] In one form, the leak flow rate estimation algorithm 4316 receives as inputs the total flow rate Qt, the exhaust flow rate Qv, and the estimated pressure Pm in the patient interface 3000, and provides as output the leak flow rate Ql by calculating the leak conductivity and determining the leak flow rate Ql as a function of the leak conductivity and the pressure Pm. The leak conductivity is calculated as the quotient of the low-pass filtered non-exhaust flow rate equal to the difference between the total flow rate Qt and the exhaust flow rate Qv and the low-pass filtered square root of the pressure Pm, where the low-pass filter time constant has a value long enough to include several breathing cycles (e.g., about 10 seconds). The leak flow rate Ql can be estimated as the product of the leak conductivity and the pressure Pm.

[0203] 8.4.3.1.4 Respiratory flow rate estimation

[0204] In one form of the present technology, the respiratory flow rate estimation algorithm 4318 receives as input the total flow rate Qt, the exhaust flow rate Qv and the leakage flow rate Ql and estimates the respiratory flow rate Qr to the patient by subtracting the exhaust flow rate Qv and the leakage flow rate Ql from the total flow rate Qt.

[0205] 8.4.3.1.5 Interference Detection

[0206] The state designated as "Jamming" occurs when the leak has recently changed and the leak flow estimation algorithm 4316 has not fully compensated for the change. In a jamming state, the respiratory flow baseline is typically incorrect to some extent, which distorts the flow shape and affects the detection of flow limitation. For example, if the respiratory flow baseline is higher than the true level, the respiratory flow of a late exhalation will be positive and can be considered as an early inspiratory flow; if this is an expiratory pause flow, the correct start of inspiration can be considered as an increase after the plateau portion of the reverse chair waveform. Therefore, a fuzzy truth variable, Recent Jamming, is calculated by the jamming detection algorithm 4319 to represent the degree of recent jamming (i.e., uncompensated leak).

[0207] In the disturbance detection algorithm 4319, the instantaneous disturbance fuzzy truth variable J is calculated as the absolute value of the respiratory flow rate Qr is always greater than the expected fuzziness. The time t from the last positive zero crossing of the respiratory flow rate Qr and the inspiratory duration Ti ZI , calculate the blur level A when the respiratory flow rate is positive for a longer time than expected I , using the following fuzzy membership function:

[0208] A I = fuzzy element (t ZI ,Ti,0,2*Ti,1) (1)

[0209] Calculate the blur level B when the airflow rate is large and positive according to the respiratory flow rate Qr I , using the following fuzzy membership function:

[0210] B I = fuzzy element (Qr, 0, 0, 0.5, 1) (2)

[0211] Leakage suddenly increases the blur level I I is calculated as the fuzzy truth variable A I and B I The fuzzy “and”.

[0212] An exact symmetric calculation of the exhalation yields I E As the fuzzy degree of leakage sudden reduction. Using the fuzzy membership function of equation (1), the time t of the last negative zero crossing of the respiratory flow rate Qr and the exhalation duration Te is ZI , calculate the blur level A where the airflow velocity is negative for longer than expected E Using the fuzzy membership function of equation (2), the fuzzy degree B of the negative value of the respiratory flow rate is calculated from the negative value of the respiratory flow rate. E , and I E Calculated as fuzzy truth variable A E and B EThe instantaneous interference index J is calculated as the fuzzy truth variable I I and I E The fuzzy “or”.

[0213] If the instantaneous jamming value J is greater than the recent peak value of J, RecentJamming is set to the instantaneous jamming value J. Otherwise, RecentJamming is set to the instantaneous jamming value J with a low-pass filter having a time constant of 10 seconds.

[0214] 8.4.3.2 Therapy Engine Module

[0215] In one form of the present technology, therapy engine module 4320 receives as input one or more of pressure Pm in patient interface 3000, and respiratory flow rate Qr of gas to the patient, and provides as output one or more therapy parameters.

[0216] In one form of the present technology, the therapy parameter is therapy pressure Pt.

[0217] In one form of the present technology, the therapy parameter is one or more of pressure amplitude, basal pressure, and target ventilation.

[0218] In various forms, the therapy engine module 4320 includes one or more of the following algorithms: phase determination 4321, waveform determination 4322, ventilation determination 4323, inspiratory flow limitation determination 4324, apnea / hypopnea determination 4325, snoring determination 4326, target ventilation determination 4327, sleep state determination 4328 and therapy parameter determination 4329.

[0219] 8.4.3.2.1 Phase determination

[0220] In one form of the present technology, the RPT device 4000 is phase indeterminate.

[0221] In one form of the present technology, the phase determination algorithm 4321 receives as input a signal representing the respiratory flow rate Qr and provides as output the phase Φ of the current respiratory cycle of the patient 1000.

[0222] In some forms, referred to as discrete phase determination, the phase output Φ is a discrete variable. One embodiment of discrete phase determination provides a two-value phase output having either an inspiratory or expiratory value, such as values ​​represented as 0 and 0.5 turns, respectively, based on the onset of spontaneous inspiration and expiration detected, respectively. The "triggered" and "cycled" RPT device 4000 effectively performs discrete phase determination because the trigger and cycle points are the intervals of phase change from exhalation to inspiration and from inspiration to exhalation, respectively. In one embodiment of two-value phase determination, the phase output Φ is determined to have a discrete value of 0 (thereby "triggering" the RPT device 4000) when the respiratory flow rate Qr has a value above a threshold, and a discrete value of 0.5 turns (thereby "cycling" the RPT device 4000) when the respiratory flow rate Qr has a value below the threshold. The inspiratory time Ti and the expiratory time Te can be obtained by subtracting the cycle time from the trigger time and subtracting the trigger time from the cycle time, respectively.

[0223] Another embodiment of discrete phase determination provides a three-valued phase output Φ having a value of one of inspiration, mid-inspiratory pause, and expiration.

[0224] In other forms, referred to as continuous phase determination, the phase output Φ is a continuous value, for example varying from 0 to 1 turn, or 0 to 2π radians. An RPT device 4000 performing continuous phase determination may trigger and loop when the continuous phase reaches 0 and 0.5 turns, respectively. In one embodiment of continuous phase determination, a fuzzy logic analysis of the respiratory flow rate Qr is used to determine the continuous values ​​of the phase Φ. The continuous values ​​of the phase determined in this embodiment are generally referred to as "fuzzy phase". In one embodiment of the fuzzy phase determination algorithm 4321, the following rules are applied to the respiratory flow rate Qr:

[0225] 1. If the respiratory flow is zero and increases rapidly, the phase is 0 turns.

[0226] 2. If the respiratory flow is large, positive and stable, the phase is 0.25 turns.

[0227] 3. If the respiratory flow is zero and decreases rapidly, the phase is 0.5 turns.

[0228] 4. If the respiratory flow is largely negative and stable, the phase is 0.75 turns.

[0229] 5. If the respiratory flow is zero, stable, and the absolute value of the 5-second low-pass filter of the respiratory flow is large, the phase is 0.9 turns.

[0230] 6. If the respiratory flow is positive and it is the exhalation phase, the phase is 0 revolutions.

[0231] 7. If the respiratory flow is negative and it is the inspiratory phase, the phase is 0.5 turns

[0232] 8. If the absolute value of a 5 second low pass filter of the respiratory flow is large and the phase increases at a steady rate equal to the patient's respiratory rate, then the low pass filter has a time constant of 20 seconds.

[0233] The output of each rule can be represented as a vector whose phase is the result of the rule, and whose magnitude is the ambiguity of the rule being true. The ambiguity of respiratory flow rate "large", "steady", etc. is determined using appropriate membership functions. The results of the rules, represented as vectors, are then combined by some function, such as taking the centroid. In such a combination, the rules can be weighted equally, or differently.

[0234] Once the phase Φ is estimated (either discretely or continuously), the inspiration time Ti and the expiration time Te are calculated as the respective durations of the intervals between when the phase reaches 0 and when it reaches 0.5, and when it reaches 0.5 and when it returns to 0.

[0235] In another embodiment of continuous phase determination, the inspiratory time Ti and the expiratory time Te are first estimated from the respiratory flow rate Qr, for example, by threshold comparison as described above. The phase Φ is then determined as half of the proportion of the inspiratory time Ti that has passed since the previous trigger moment, or 0.5 turns plus half of the proportion of the expiratory time Te that has passed since the previous cycle moment (whichever is newer).

[0236] 8.4.3.2.2 Waveform determination

[0237] In some forms of the present technology, the therapy parameter determination algorithm 4329 provides an approximately constant therapy pressure throughout the patient's breathing cycle.

[0238] In other forms 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 predetermined waveform template II (Φ).

[0239] In this form of the present technology, the waveform determination algorithm 4322 provides a waveform template II (Φ) with a value in the range [0, 1] from the phase value domain provided by the phase determination algorithm 4321. The waveform template II (Φ) is used by the therapy parameter determination algorithm 4329.

[0240] The waveform template II (Φ) can be used as a numerical lookup table of a function of the phase value Φ. This method is particularly suitable when the phase determination algorithm 4321 returns discrete values ​​of the phase, such as 0 for inspiration and 0.5 for expiration. This method can also be used when the phase determination algorithm 4321 returns a continuous value phase Φ.

[0241] In one form, applicable to discrete or continuous-valued phases, the waveform template II(Φ) is a square-wave template that has a value of 1 for phase values that are at maximum and include 0.5 revolutions, and a value of 0 for phase values that exceed 0.5 revolutions. In one form, applicable to continuous-valued phases, the waveform template II(Φ) includes two smoothly curved portions, namely, a smooth (such as a raised cosine) curve rising from 0 to 1 for phase values that are at maximum and include 0.5 revolutions, and a smooth (such as exponential) decay from 1 to 0 for phase values that exceed 0.5 revolutions. A typical waveform template II(Φ) in this "smooth and comfortable" form is as Figure 8 shown.

[0242] 8.4.3.2.3 Ventilation Volume Determination

[0243] In one form of the present technology, the ventilation volume determination algorithm 4323 receives the respiratory flow rate Qr as an input and determines a measured value, Vent, indicative of the current patient ventilation volume.

[0244] In some embodiments, the ventilation volume determination algorithm 4323 determines a measured value of the ventilation volume Vent, which is an estimate of the actual patient ventilation volume. Such an embodiment is to filter optionally half of the absolute value of the respiratory flow rate Qr by a low-pass filter (such as a second-order Bessel low-pass filter with an angular frequency of 0.11 Hz).

[0245] In other embodiments, the ventilation volume determination algorithm 4323 determines a measured value of the ventilation volume Vent, which is approximately proportional to the actual patient ventilation volume. Such an embodiment estimates the peak respiratory flow rate Qpeak during the inspiratory portion of the cycle. This and many other processes involving sampling the respiratory flow rate Qr produce measured values that are approximately proportional to the ventilation volume, as long as the flow rate waveform shape does not vary greatly (here, when the flow rate waveforms of normal breaths in terms of time and amplitude are similar, the shapes of two breaths are considered similar). Some simple examples include the median of the respiratory flow with a positive value, the median of the absolute value of the respiratory flow rate, and the standard deviation of the flow rate. Any linear combination of any order statistics of the absolute value of the respiratory flow rate using positive coefficients, and even some using both positive and negative coefficients, is approximately proportional to the ventilation volume. Another example is the average of the respiratory flow rate for the middle K proportion (by time) of the inspiratory portion, where 0 < K < 1. If the flow rate shape remains constant, there can be any number of measured values that are exactly proportional to the ventilation volume.

[0246] 8.4.3.2.4 Inspiratory Flow Limitation Determination

[0247] In one form of the present technology, the central controller 4230 executes an inspiratory flow limitation determination algorithm 4324 for determining the degree of inspiratory flow limitation.

[0248] In one form, the inspiratory flow limitation determination algorithm 4324 receives as input the respiratory flow rate signal Qr and provides as output a measure of the degree to which the inspiratory portion of the breath exhibits inspiratory flow limitation.

[0249] Algorithm 4324 may calculate a metric based on at least one of three types of inspiratory flow limitation: plateau, M-shaped, and "reverse chair" (see for examples of each). Fig. 6E , 6I and 6H).

[0250] One example of a method that may be used to implement the inspiratory flow limitation determination algorithm 4324 may be found in commonly owned PCT patent application PCT / AU2015 / 050496 filed on August 27, 2015, the entire contents of which are incorporated herein by reference.

[0251] 8.4.3.2.5 Determination of apnea and hypopnea

[0252] 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.

[0253] In one form, the apnea / hypopnea determination algorithm 4325 receives as input the respiratory flow rate signal Qr and provides as output a flag indicating that an apnea or hypopnea has been detected.

[0254] In one form, when the function of respiratory flow rate Qr is below a flow threshold for a predetermined period of time, apnea may be considered to have been detected. The function may determine a peak flow rate, a relatively short-term average flow rate, or an intermediate flow rate between a relatively short-term average and peak flow rate (e.g., RMS flow rate). The flow rate threshold may be a measure of relatively long-term flow rate.

[0255] In one form, when the function of the respiratory flow rate Qr is below a second flow rate threshold for a predetermined time period, hypopnea may be considered to have been detected. The function may determine a peak flow rate, a relatively short-term average flow rate, or an intermediate flow rate of a relatively short-term average and peak flow rate (e.g., RMS flow rate). The second flow rate threshold may be a measure of a relatively long-term flow rate. The second flow rate threshold is greater than a flow rate threshold for detecting apnea.

[0256] 8.4.3.2.6 Snoring Determination

[0257] In one form of the present technology, the central controller 4230 executes one or more snoring determination algorithms 4326 to determine the extent of snoring.

[0258] In one form, the snoring determination algorithm 4326 receives as input a signal of respiratory flow rate Qr and provides as output a measure of the degree to which snoring is present.

[0259] The snore determination algorithm 4326 may include a step of determining the flow rate signal strength in the range of 30-300 Hz. In addition, the snore determination algorithm 4326 may include a step of filtering the signal of the respiratory flow rate Qr to reduce background noise (eg, the sound of airflow from a blower system).

[0260] 8.4.3.2.7 Determination of target ventilation

[0261] In one form of the present technology, the central controller 4230 takes as input a measured value of the current ventilation Vent and executes one or more target ventilation determination algorithms 4327 to determine a target value Vtgt for the measured ventilation.

[0262] In some forms of the present technology, there is no target ventilation determination algorithm 4327 and the target value Vtgt is predetermined, for example by hard coding during configuration of the RPT device 4000 or by manual entry via the input device 4220.

[0263] In other forms of the present technology, such as adaptive servo-ventilation (ASV), the target ventilation determination algorithm 4327 calculates the target value Vtgt from a value Vtyp indicative of the patient's typical recent ventilation.

[0264] In some forms of adaptive servo-ventilation, the target ventilation Vtgt is calculated as a high ratio, but less than the typical recent ventilation Vtyp. These forms of high ratios may be in the range of (80%, 100%), or (85%, 95%), or (87%, 92%).

[0265] The typical recent ventilation Vtyp is the value around which the distribution of the measured values ​​of the current ventilation Vent for multiple time periods within some predetermined time range tends to cluster, that is, a measure of the central tendency of the measured values ​​of the current ventilation in the recent history. In one embodiment of the target ventilation determination algorithm 4327, the recent history is on the order of a few minutes, but in any case should be longer than the time scale of the tidal increase and decrease cycle. The target ventilation determination algorithm 4327 can use various known central tendency measures to determine the typical recent ventilation Vtyp of the current ventilation Vent. One such measurement is the output of a low-pass filter on the measured value of the current ventilation Vent, with a time constant equal to 100 seconds.

[0266] 8.4.3.2.8 Sleep state determination

[0267] In some forms of the present technology, the central controller 4230 executes one or more algorithms 4328 for determining a sleep state. The sleep state determination algorithm 4328 can monitor and analyze signals representing physiological parameters of the patient to determine the sleep state. In some embodiments, the physiological parameter is the respiratory flow rate Qr. In such an embodiment, it is first assumed that the patient is in a wakeful state. If one or all of the following conditions are detected in the respiratory flow rate Qr, the onset of sleep is detected, thereby determining that a sleep state has been entered:

[0268] Multiple occurrences of SDB events within a first predetermined interval, such as flow limitation, apnea, hypopnea, or snoring as detected above. For example, three or more obstructive apnea or hypopnea events within a two-minute interval; or 5 snoring within a 5-breath interval.

[0269] Absence of breathing disorder for the second predetermined interval. The second predetermined interval may range from 10 to 50 breaths, or 20 to 40 breaths, or 25 to 35 breaths, or from 1 to 10 minutes, 1 to 5 minutes, or 2, 3, 4, 5, 6, 7, 8, or 9 minutes, or other time limits. To detect the absence of breathing disorder, the sleep state determination algorithm 4328 may test for the absence of changes within the second predetermined interval in one or more of the following breathing variables:

[0270] ○ Tidal volume Vt;

[0271] ○ Inspiratory time Ti;

[0272] ○Respiratory rate;

[0273] ○ Peak inspiratory flow rate Qpeak;

[0274] ○ Peak expiratory flow rate position;

[0275] ○ Time since last breath.

[0276] Other methods may be employed to use the patient's respiratory flow rate Qr to implement the sleep state determination algorithm 4328. One example may be found in commonly owned PCT patent application PCT / AU2010 / 000894 entitled "Detection of Sleep Condition," published as WO 2011 / 006199, the entire contents of which are incorporated herein by reference.

[0277] In other embodiments, the physiological parameter that determines the sleep state is obtained from another sensor. The other sensor may form part of the RPT device transducer 4270, or may be a local external device 4288 that communicates with the RPT device via a local network 4284. In one example, the other sensor is a photoplethysmogram that provides a pulse oximetry signal. In another example, the other sensor is an actigraph (3D accelerometer) that provides a motion (activity) signal. In yet another example, the other sensor is an audio sensor.

[0278] 8.4.3.2.9 Determination of therapy parameters

[0279] 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.

[0280] In one form of the present technology, the therapy parameter is the immediate therapy pressure Pt. In one embodiment of this form, the therapy parameter determination algorithm 4329 uses the equation

[0281] Pt=AΠ(Φ)+P0 (3)

[0282] Determine the treatment pressure Pt.

[0283] in:

[0284] A is the amplitude,

[0285] II(Φ) is the waveform template value of the current phase value Φ (in the range of 0 to 1),

[0286] P0 is the base pressure.

[0287] If the waveform determination algorithm 4322 provides the waveform template II (Φ) as a numerical lookup table indexed by phase II, the therapy parameter determination algorithm 4329 applies equation (3) by locating the nearest lookup table entry to the current value of the phase returned by the phase determination algorithm 4321, or by interpolating between two entries spanning the current value of the phase.

[0288] Depending on the selected respiratory pressure therapy mode, the values ​​of amplitude A and basal pressure P0 can be predetermined or calculated by the therapy parameter determination algorithm 4329, as described below.

[0289] 8.4.3.3 Therapy Control Module

[0290] The therapy control module 4330 in accordance with one form of the present technology receives as input therapy parameters from a therapy parameter determination algorithm 4329 of the therapy engine module 4320 and controls the pressure generator 4140 to deliver air flow in accordance with the therapy parameters.

[0291] 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 air flow at a mask pressure Pm at the patient interface 3000 equal to the therapy pressure Pt.

[0292] 8.4.3.4 Fault status detection

[0293] In one form of the present technology, the central controller 4230 performs one or more methods for detecting a fault condition. The fault condition detected by the one or more methods may include at least one of the following:

[0294] Power failure (no power, or insufficient power)

[0295] Transducer fault detection

[0296] Unable to detect the presence of components

[0297] Operating parameters outside the recommended range (e.g., pressure, airflow, temperature, PaO2)

[0298] The test alarm fails to produce a detectable alarm signal.

[0299] After detecting a fault condition, the corresponding algorithm indicates the presence of a fault through one or more of the following signals:

[0300] Activate audible, visual and / or dynamic (e.g. vibration) alarms

[0301] Send messages to external devices

[0302] Recording events

[0303] 8.5 Humidifier

[0304] In one form of the present technology, a humidifier 5000 (e.g., Figure 5 ) to change the absolute humidity of air or gas relative to the surrounding air for delivery to the patient. Typically, the humidifier 5000 is used to increase the absolute humidity and increase the temperature of the air flow (relative to the surrounding air) before delivery to the patient's airway.

[0305] 8.6 Respiratory Waveform

[0306] Fig. 6AA typical breathing waveform of a person during sleep is shown. The horizontal axis is time and the vertical axis is respiratory flow rate. Parameter values ​​may vary, and a typical breath may have the following approximate values: tidal volume, Vt, 0.5L, inspiratory time, Ti, 1.6s, peak inspiratory flow rate, Qpeak, 0.4L / s, expiratory time, Te, 2.4s, peak expiratory flow rate, Qpeak, -0.5L / s. The total duration of the breath, Ttot, is about 4s. The human respiratory rate is typically 15 breaths / minute (BPM), and the ventilation volume, Vent, is about 7.5L / minute. For a typical duty cycle, the ratio of Ti to Ttot is about 40%.

[0307] Figure 6B A patient during non-REM sleep is shown taking about 34 breaths typically in about 90 seconds, treated with APAP at a mask pressure of about 11 cmH2O. The top channel shows blood oxygen (SpO2) with a scale having a saturation range of 90 to 99% in the vertical direction. The patient maintained about 95% saturation throughout the period shown. The second channel shows quantitative respiratory airflow with a vertical range of -1 to +1 LPS with inspiration being positive. Chest and abdominal movements are shown in the third and fourth channels.

[0308] Figure 6C The polysomnogram of the patient before treatment is shown. There are 11 signal channels from top to bottom, with a horizontal span of 6 minutes. The two channels at the top are EEG (electroencephalogram) from different scalp positions. The periodic spikes of the second EEG represent cortical awakening and related activities. The third channel is submental EMG (electromyogram). The increasing activity before and after awakening represents the recruitment of the genioglossus muscle. The fourth and fifth channels are EOG (electrooculogram). The sixth channel is an electrocardiogram. The seventh channel shows that the pulse oxygen (SpO2) of repeated desaturation drops from about 90% to below 70%. The eighth channel is the respiratory airflow using a nasal cannula connected to a differential pressure transducer. 25 to 35 seconds of repeated apnea alternates with 10 to 15 seconds of paroxysmal recovery breathing consistent with EEG awakening and increased EMG activity. The ninth channel shows chest movement, and the tenth channel shows abdominal movement. The abdomen shows a gradual strengthening of movement during the apnea period that causes awakening. During awakening, both become untidy due to the overall movement during the recovery of hyperpnea. Apnea is thus blocked and the condition is serious. The lowest channel is body position, and in this example, no changes are shown.

[0309] Fig.6D Flow data for a patient is shown while the patient is experiencing a series of total obstructive apneas. The duration of the recording is approximately 160 seconds. The flow range is approximately +1 L / s to approximately -1.5 L / s. Each apnea lasts approximately 10-15 seconds.

[0310] Fig. 6EA zoomed inspiratory portion of a breath is shown when the patient is experiencing low frequency inspiratory snoring.

[0311] Fig. 6F Shown is a zoomed inspiratory portion of a breath when the patient is experiencing an example of a normal or "table-shaped" plateau of inspiratory flow limitation.

[0312] Figure 6G Shown is a zoomed inspiratory portion of a breath where a patient is experiencing an example of "chair" inspiratory flow limitation.

[0313] Figure 6H Shown is a zoomed inspiratory portion of a breath where a patient is experiencing an example of "reverse chair" inspiratory flow limitation.

[0314] Fig.6I Shown is a zoomed inspiratory portion of a breath where a patient is experiencing an example of "M-shaped" inspiratory flow limitation.

[0315] Figure 6J Patient data from a Cheyne-Stokes patient is shown. There are three channels: blood oxygen saturation (SpO2); a signal indicating flow rate; and chest motion. The time span of the data is six minutes. The signal representing flow rate is measured using a pressure sensor connected to a nasal cannula. The patient exhibited approximately 22 seconds of apnea and approximately 38 seconds of hyperpnea. The higher frequency, low-amplitude oscillations during the apnea are of cardiogenic origin.

[0316] 8.7 Respiratory Pressure Therapy Mode

[0317] The RPT device 4000 may implement various respiratory pressure therapy modes based on the values ​​of parameters A and P in the therapy pressure equation (3) used by a therapy parameter determination algorithm 4329 of one form of the present technology.

[0318] 8.7.1 CPAP therapy

[0319] In some embodiments of this form of the present technology, the amplitude A is constant at zero, so that the treatment pressure Pt is constant with the base pressure P0 throughout the respiratory cycle. These embodiments are generally grouped under the CPAP therapy heading. In these embodiments, the therapy engine module 4320 does not need to determine the phase Φ or waveform template II (Φ).

[0320] In CPAP therapy mode, the basal pressure P0 can be a constant value that is hard-coded or manually entered into the RPT device 4000 during configuration. This alternative approach is sometimes referred to as constant CPAP therapy. A constant value for the basal pressure P0 can be selected for a given patient by a process known as titration. During titration, the clinician typically adjusts the treatment pressure Pt based on observations of flow limitation, apnea, hypopnea, and snoring. The titrated basal pressure P0 can then be calculated as a statistical summary of the treatment pressures Pt during the titration period.

[0321] Alternatively, the therapy parameter determination algorithm 4329 can repeatedly calculate the basal pressure P0 during CPAP therapy. In this alternative, the therapy parameter determination algorithm 4329 repeatedly calculates the basal pressure P0 as a function of an indicator or measurement of sleep breathing disorders returned by a corresponding algorithm in the therapy engine module 4320, such as one or more of flow limitation, apnea, hypopnea, and snoring. This alternative method is sometimes referred to as APAP therapy. Because the continuous calculation of the basal pressure P0 is similar to the manual adjustment of the treatment pressure Pt by the clinician during the titration process, APAP therapy is sometimes also referred to as auto-titration CPAP.

[0322] 8.7.2 Bi-level therapy

[0323] In other embodiments of this form of the present technology, the value of the amplitude A in equation (3) may be positive. These embodiments are referred to as bi-level therapy because when the therapy pressure Pt is determined using equation (3) with a positive amplitude A, the therapy parameter determination algorithm 4329 fluctuates the therapy pressure Pt between two values ​​or levels that are synchronized with the spontaneous breathing of the patient 1000. That is, based on the typical waveform template II (Φ) described above, the therapy parameter determination algorithm 4329 increases the therapy pressure Pt to P0+A (referred to as IPAP) at the beginning or during therapy or during inspiration, and reduces the therapy pressure Pt to the base pressure P0 at the beginning or during exhalation.

[0324] In some forms of bi-level therapy, IPAP is the therapy pressure, which has the same purpose as the therapy pressure in the CPAP therapy mode, and EPAP is IPAP minus amplitude A, which has a "small" value (a few cmH2O), sometimes referred to as expiratory pressure relief (EPR). These forms are sometimes referred to as CPAP therapy with EPR, which is generally considered to be more comfortable than straight CPAP therapy. In CPAP therapy with EPR, one or both of IPAP and EPAP can be constant values ​​that are hard-coded or manually entered into the RPT device 4000 during configuration. Alternatively, the therapy parameter determination algorithm 4329 can repeatedly calculate IPAP and / or EPAP during CPAP with EPR. In this alternative, the therapy parameter determination algorithm 4329 repeatedly calculates EPAP and / or IPAP as a function of an indicator or measurement of sleep disordered breathing returned by the corresponding algorithm in the therapy engine module 4320, which is similar to the calculation of the basal pressure P0 in the APAP therapy described above.

[0325] In other forms of bi-level therapy, Amplitude A is large enough that the RPT device 4000 performs some or all of the work of breathing for the patient 1000. In these forms, referred to as pressure support ventilation therapy, Amplitude A is referred to as pressure support, or switching. In pressure support ventilation therapy, IPAP is the base pressure P0 plus pressure support A, and EPAP is the base pressure P0.

[0326] In some forms of pressure support ventilation therapy, referred to as fixed pressure support ventilation therapy, pressure support A is fixed at a predetermined value, for example, 10 cmH 2 O. The predetermined pressure support value is a setting of the RPT device 4000 and may be set, for example, by hard coding during configuration of the RPT device 4000 or by manual entry through the input device 4220.

[0327] In some forms of pressure support ventilation therapy, referred to as servo-ventilation, the therapy parameter determination algorithm 4329 takes as input the current measured value of ventilation Vent and the target value Vtgt provided by the target ventilation determination algorithm 4327, and iteratively adjusts the parameters of equation (3) to move the current measured value of ventilation Vent toward the target value Vtgt. In a form of servo-ventilation referred to as adaptive servo-ventilation (ASV), which has been used to treat periodic breathing, particularly CSR, the target ventilation Vtgt is calculated by the target ventilation determination algorithm 4327 based on the typical recent ventilation Vtyp, as described above.

[0328] In some forms of servo-ventilation, the therapy parameter determination algorithm 4329 applies a control method to repeatedly calculate the pressure support A so that the current measurement of ventilation Vent reaches the target ventilation Vtgt. One such control method is proportional-integral (PI) control. In one embodiment of PI control, suitable for an ASV mode that sets the target ventilation Vtgt to be slightly less than the typical recent ventilation Vtyp, the pressure support A is calculated as follows:

[0329] A=G∫(Vent-Vtgt)dt (4)

[0330] Where G is the gain value of the PI control. Larger gain G values ​​may result in positive feedback in the therapy engine module 4320. Smaller gain G values ​​may allow some remaining untreated CSR or other periodic breathing. In some embodiments, the gain G is fixed to a predetermined value, such as 0.4 cmH2O / (L / min) / s.

[0331] In some embodiments of servo-ventilation, the value of the pressure support A calculated by equation (4) can be limited to a range defined as [Amin, Amax]. In these embodiments, the pressure support A is at the lowest pressure support Amin by default until the current ventilation measurement value Vent is lower than the target ventilation Vtgt, at which time the position A starts to increase, and only returns to Amin when Vent exceeds Vtgt again.

[0332] The pressure support limits Amin and Amax are settings of the RPT device 4000, such as by hard coding during configuration of the RPT device 4000 or by manual entry through the input device 4220. The minimum pressure support Amin of 3 cmH2O is approximately 50% of the pressure support required to perform all the work of a typical patient breathing in a steady state. The maximum pressure support Amax of 12 cmH2O is approximately twice the pressure support required to perform all the work of a typical patient breathing, and therefore is sufficient to support the patient's breathing if they cease to work, but not enough to make the patient uncomfortable or dangerous.

[0333] In pressure support ventilation therapy mode, EPAP is the basal pressure P0. Similar to the basal pressure P0 in CPAP therapy, EPAP can be a constant value that is specified or determined during a titration process. This type of constant EPAP can be set, for example, by hard coding the configuration of the RPT device 4000 or by manual input of the input device 4220. This alternative is sometimes referred to as fixed EPAP pressure support ventilation therapy. Titration of EPAP for a given patient can be performed by the clinician during the titration period with the goal of maintaining airway patency and thereby preventing obstructive apnea throughout the pressure support ventilation therapy, similar to the titration of the basal pressure P0 in conventional CPAP therapy.

[0334] Alternatively, the therapy parameter determination algorithm 4329 can repeatedly calculate EPAP during pressure support ventilation therapy. In these embodiments, the therapy parameter determination algorithm 4329 repeatedly calculates EPAP as a function of indicators or measurements of sleep-disordered breathing, such as flow limitation, apnea, hypopnea, and snoring, returned by the corresponding algorithm in the therapy engine module 4320. Because the continuous calculation of EPAP is similar to the manual adjustment of EPAP by the clinician during EPAP titration, this process is sometimes referred to as automatic titration of EPAP, and the therapy mode is referred to as automatically titrating EPAP pressure support ventilation therapy, or automatic EPAP pressure support ventilation therapy.

[0335] Automatic titration of EPAP for patients with SDB-associated insomnia on pressure support ventilation therapy appears particularly difficult because such patients can awaken in response to relatively minor SDB events. After being awakened, they may find it difficult to reestablish sleep. Therefore, occasional minor obstruction or respiratory event-related arousals (RERAs) may be acceptable in the general population but are disadvantageous in patients with sleep maintenance insomnia. Therefore, automatic titration of EPAP for these patients is more important to maintain airway patency than simply responding to obstructive events. The following section describes an algorithm for automatic titration of pressure support ventilation therapy that is applicable to patients with SDB-associated insomnia.

[0336] 8.7.2.1 Automatic titration of EPAP

[0337] In one embodiment of automatic titration of EPAP, a number of different features indicative of upper airway obstruction (UAO), if present, result in an increase in EPAP that is roughly proportional to the severity of the UAO. When no features indicative of UAO are present, EPAP gradually decays to a minimum pressure limit (sometimes referred to simply as "minimum pressure") or minimum minEPAP. This decay tends to minimize the transmission of EPAP. At any given time, EPAP is a balance between forces tending to increase it and forces tending to decay it. An approximate balance can be reached in which occasional indicators of mild UAO result in an upward movement in EPAP that is offset by the decay that occurs when there is no UAO indicator.

[0338] The EPAP response to the indication of flow limitation is gradual (i.e., a greater EPAP component resulting from a more severe flow limitation is greater than an EPAP component resulting from a less severe flow limitation) because flow limitation becomes progressively more severe, requiring a quick response to prevent apneas or increased arousals, and also because there is less uncertainty about the presence of flow limitation. Control systems with gradual responsiveness to signals are also almost always more stable and generally perform better than those that have larger changes in response to small changes in signal level. For example, in some variations, the gradual response may be a response that is proportional to the indication of flow limitation. However, in some variations, the gradual response need not be strictly related to a constant ratio or gain value relative to the indication of flow limitation.

[0339] When therapy parameter determination algorithm 4329 prescribes an increase in EPAP, the increase may not occur immediately. This rise in EPAP may be controlled by controller 4230 and timed to occur only during what the RPT device 4000 deems to be inspiration. It is believed that a rise in EPAP during exhalation is more likely to cause arousal than during inspiration, perhaps because a rise during inspiration reduces the work of inspiration, whereas a rise during exhalation tends to push the patient into the next inspiration. An example of this technique is disclosed in U.S. Patent Application Publication No. 2011 / 0203588A1, the entire contents of which are incorporated herein by reference.

[0340] Figure 7 is a flow chart showing a method 7000 for determining a new value of EPAP, CurrentEPAP, as a function of various measures of UAO calculated by algorithms 4324 (inspiratory flow limitation), 4325 (apnea and hypopnea), and 4326 (snoring). Method 7000 may be used repeatedly by therapy parameter determination algorithm 4329 to automatically titrate EPAP during pressure support ventilation therapy.

[0341] Method 7000 calculates five independent components of EPAP above the minimum pressure minEPAP: EPAP of step 7010 (1,2) (due to apnea and / or hypopnea), EPAP of step 7020 (3) (due to the stability of inspiratory flow), EPAP in step 7030 (4) (due to the M-shaped inspiratory flow), EPAP of step 7040 (5) (Reverse chair due to inspiratory flow), EPAP at step 7050 (6)(due to snoring). Step 7060 adds these five components to the minimum pressure minEPAP. Finally, at step 7070, method 7000 ensures that the resulting new value of CurrentEPAP does not exceed the maximum value maxEPAP. In other words, step 7070 caps the newly calculated value of CurrentEPAP to maxEPAP. Method 7000 then reaches a conclusion.

[0342] In addition to the corresponding measured values ​​of UAO, each of steps 7010 to 7050 takes as input one or more of the following RPT device variables or signals: respiratory flow rate Qr, leak flow rate Ql, current target ventilation Vtgt, current value of CurrentEPAP, amount of pressure support A, instantaneous treatment pressure Pt, and recent interference fuzzy truth variable RecentJamming.

[0343] Further details regarding steps 7010 to 7050 may be found in PCT patent application PCT / AU2013 / 000382, published as WO2013 / 152403, the entire contents of which are incorporated herein by reference.

[0344] In general, stronger evidence is needed to demonstrate that the EPAP is increased by the same magnitude compared to the current value of the EPAP because the potential adverse consequences of an increased EPAP increase with increasing EPAP values. These consequences are a decrease in the maximum possible pressure support for a given fixed maximum treatment pressure and a greater susceptibility to leaks. The confidence level in the accuracy of the calculated respiratory flow waveform decreases with increasing leak flow rates because the leak pattern tends to be less precise with increasing leak flow magnitude.

[0345] In a variation of method 7000, if the sleep state determination algorithm 4328 determines that the patient is in a sleep state, the EPAP, currentEPAP, may not be decreased from its current value. In such a variation, if the sleep state determination algorithm 4328 determines that the patient is in a sleep state, the new value of currentEPAP after step 7070 is compared with the previous value of currentEPAP, and if the new value is less than the previous value, the value of currentEPAP remains unchanged. In this variation, when it is determined that the patient is in a sleep state, the EPAP cannot be decreased, but only increased or remains unchanged, so as to minimize the chance of arousal of easily arousable people due to upper airway resistance.

[0346] 8.7.2.2 Minimum pressure limit adjustment

[0347] In pressure support ventilation therapy, the treatment pressure determined using equation (3) is always greater than or equal to EPAP. In some embodiments of pressure support ventilation therapy with automatic titration of EPAP, such as the one described above, EPAP may be limited to varying within a range with a minimum value or lowest pressure minEPAP as a lower boundary and a maximum value maxEPAP as an upper boundary. This means that the treatment pressure Pt is bounded below by the lowest pressure minEPAP used as the lower limit of the EPAP pressure. In some such embodiments of automatic titration of EPAP, the minimum pressure minEPAP and the maximum value maxEPAP may be constant values ​​that are hard-coded or manually entered into the RPT device 4000 during configuration. Typical constant values ​​of the minimum pressure minEPAP and the maximum value maxEPAP are 4 and 15 cmH2O, respectively.

[0348] In other embodiments of EPAP automatic titration, the minimum pressure minEPAP can be repeatedly adjusted according to events of interest during EPAP automatic titration. This method uses an optional minimum pressure minEPAP calculation process 7059 in Figure 7 4059. In some such embodiments, the therapy parameter determination algorithm 4329 may repeatedly adjust the minimum pressure minEPAP in parallel with the automatic titration of EPAP, such as through process 7059. In one such embodiment, the therapy parameter determination algorithm 4329 repeatedly adjusts the minimum pressure minEPAP according to the number of events of interest that occur in a predetermined interval Ta. That is, if Na or more events of interest occur within an interval of Ta seconds, minEPAP will be increased by an increment of ΔminEPAP. In one such embodiment, the event of interest is an SDB event, such as inspiratory flow limitation, apnea, hypopnea, or snoring determined by the measurements of these quantities obtained by the therapy engine module 4320 as described above. In one example of such an embodiment, ΔminEPAP is predetermined at 1 cmH2O, Na is 3, and Ta is 2 minutes. In other examples, ΔminEPAP is predetermined to other values ​​in the range of 0.2 to 4 cmH2O or 0.5 to 2 cmH2O. In other examples, Ta is predetermined to other values ​​in the range of 30 seconds to 10 minutes or 1 to 4 minutes.

[0349] In other of these embodiments, the increment ΔminEPAP is not predetermined but depends on the current value of EPAP. In one such embodiment, the increment ΔminEPAP is equal to the value of EPAP minus the current value of the minimum pressure minEPAP, such that the minimum pressure minEPAP is increased to the current value of EPAP.

[0350] In other embodiments of EPAP automatic titration, the minimum pressure minEPAP is repeatedly adjusted, and the event of interest is the recent increase in EPAP due to the automatic titration of EPAP. In these embodiments, if there have been a predetermined number of increases in EPAP within a specific time interval, it reflects that the EPAP value is lower than the current EPAP and is insufficient to maintain airway patency, so the minimum pressure minEPAP can be increased to the current EPAP. In an example of such an embodiment, at time t, the EPAP is 4 cmH2O, then after time t+3 minutes, the EPAP is 8.5 cmH2O, and the increase in EPAP within the 3 minute interval starting from time t is 10. If the threshold value of the number of increments is 9 and the threshold value of the time interval is 5 minutes, the minimum pressure minEPAP will be set to the current EPAP (8.5 cmH2O) because more than 9 increments have been exceeded in an interval of less than 5 minutes.

[0351] As an additional step to the above embodiment, the total increase in EPAP may also be taken into account. For example, if the total increase in EPAP between time t and t+3 is greater than a threshold, for example, 3 cmH2O, the minimum pressure minEPAP will be set as the current EPAP.

[0352] In other embodiments where the minimum pressure minEPAP is a variable EPAP auto-titration, the therapy parameter determination algorithm 4329 can form a distribution of EPAP values ​​where EPAP increments occur over analysis intervals that are longer (e.g., 60 minutes) than the typical interval between EPAP increments. Based on parametric or non-parametric statistical analysis of the distribution, the minimum pressure minEPAP can be adjusted. Fig. 9 An exemplary histogram 9000 is included that expresses the distribution of EPAP values ​​at which EPAP increments occur within an analysis interval (60 minutes in this example). In this example, the minimum pressure minEPAP can be set to 7 cmH2O, which is the mode (peak location) of the histogram. Other statistical extractions of the distribution can be used as the new value of the minimum pressure minEPAP, such as the mean, median, etc. Alternatively, the minimum pressure minEPAP can be "remembered" from a previous analysis interval, and the new minimum pressure minEPAP can be based on the remembered minimum pressure as well as the distribution.

[0353] The profile analysis and updating of minEPAP can be repeated at regular intervals throughout the period, for example every 60 minutes. For example, the analysis interval can be from 30 minutes to 300 minutes. The interval between the profile analysis and the adjustment of the minimum pressure minEPAP can be the same as the analysis interval, or longer, or shorter.

[0354] In one example, the distribution of EPAP increments is analyzed and the minimum pressure minEPAP is adjusted after each night of pressure support ventilation therapy. The analysis interval is a full night, or at least a portion of a full night, in which the patient is determined to be in a sleeping state by the sleep state determination algorithm 4328. Such an example is effectively a night-to-night learning of an "ideal" minimum pressure minEPAP for the patient. Such a longer analysis interval can provide benefits to the patient in the form of lower leak levels and increased comfort.

[0355] In some embodiments of EPAP automatic titration with an iteratively adjusted minimum pressure minEPAP, the therapeutic parameter determination algorithm 4329 ensures that the minimum pressure minEPAP is always less than or equal to an upper limit of minEPAP_max, such as 10 cmH 2 O. In other such embodiments, there is no such upper limit on the variable value of the minimum pressure minEPAP.

[0356] 8.7.2.3 Changes in PI gain value according to sleep state

[0357] Because patients with SDB and insomnia are often in a state of heightened anxiety and stress, they may be particularly vulnerable to being upset by any changes in therapy. Large stress swings may be undesirable while such patients are awake.

[0358] Therefore, in certain embodiments of pressure support ventilation therapy, the gain value G of the above PI control equation (4) may vary according to the sleep state determined by the sleep state determination algorithm 4328. Such a process 10000 is Fig.10 43. At 10010, a sleep state is determined, such as by a sleep state determination algorithm 4328. At 10020, a gain value, such as for controlling servo-ventilation, is adjusted based on the determined sleep state. This may be performed by a therapy parameter determination algorithm 4329. At 10030, the servo-ventilation is controlled to servo-ventilate the patient with a gain value, such as determined by a therapy control algorithm 4330. In one such embodiment, a fixed raw value of the controller gain value G0 is weighted according to the sleep state to produce an actual gain value G:

[0359] G=sleep state weight×G0(5).

[0360] If the sleep state determination algorithm 4328 determines that the patient is awake, the sleep state weight will be close to 0, so the gain value G of the servo control will be relatively low, and the servo control of pressure support A will be relatively slow to respond. On the other hand, if the sleep state determination algorithm 4328 determines that the patient is asleep, the sleep state weight will be close to 1, so the gain value G of the servo control will be relatively high, and the servo control of pressure support A will be relatively fast to respond. Vice versa, the transition of the sleep state weight from 0 to 1 can be instantaneous or gradual, such as via a linear or exponential function.

[0361] 8.7.2.4 Adaptation of pressure support ventilation therapy

[0362] As described above, patients with SDB and insomnia are often unable to tolerate conventional respiratory pressure therapy. This is partly because insomnia patients are often anxious about sleep or anxious in various aspects, and may not associate their condition with respiratory disorders. Therefore, a special "adaptation therapy" may be needed to help patients tolerate respiratory pressure therapy. Previous adaptation pathways for patients with SDB and insomnia include desensitization to the patient's interface and therapy pressure, behavioral therapy to overcome aversive emotional reactions, mental images that divert the patient's attention from the patient's interface or pressure perception, and physiological exposure to pressure support ventilation therapy during daytime sleep ("PAP-NAP").

[0363] In one form of the present technology, the adaptation therapy includes a period of "paced breathing". Paced breathing includes using pressure support ventilation to slow the patient's breathing towards an "optimal" breathing rate in a manner that the patient responds favorably so that the therapy is well tolerated. It is determined that slow paced breathing can be calming, especially in patients who are prone to hyperactivity, such as patients with SDB and insomnia.

[0364] This process 11000 Fig.11 At 11010, the RPT device controls the application of the patient's paced breathing. This can be performed by the therapy parameter determination algorithm 4329 and the therapy control algorithm 4330. At 11020, biofeedback is provided to the patient. This can also be performed by the therapy parameter determination algorithm 4329 and the therapy control algorithm 4330.

[0365] For example, a period of constant-rate breathing usually begins with the introduction phase of pressure support ventilation therapy as described above, during which the patient's spontaneous inspiratory time Ti and expiratory time Te are estimated from the respiratory flow rate Qras described above. This estimated phase Φ is used in equation (3) to calculate the phase of the patient's spontaneous inspiratory time Ti and expiratory time Te using a "smooth and comfortable" pressure waveform template II (Φ) (such as Figure 8 The treatment pressure Pt is calculated using the pressure waveform template shown in the figure.

[0366] After the introduction period, the therapy parameter determination algorithm 4329 sets the current temporary respiratory rate target. The inverse of this temporary respiratory rate target (target respiratory time tgtTtot) can be divided into a target inspiratory time tgtTi and a target expiratory time tgtTe in the same proportion as the spontaneous inspiratory time Ti and the expiratory time Te. Pressure support ventilation therapy is continued using the "smooth and comfortable" pressure waveform template II (Φ) using the phase Φ estimated as described above, via the elapsed time relative to the target inspiratory time tgtTi and the expiratory time tgtTe. This results in a "smooth and comfortable" treatment pressure Pt that promotes the patient's inspiratory time Ti and expiratory time Te to match the target inspiratory time tgtTi and the target expiratory time tgtTe. However, because the phase Φ is set to 0.5 (thereby causing the ventilator to cycle) when the respiratory flow drops below the cycle threshold, and the phase Φ is set to 0 (thereby triggering the ventilator) when the respiratory flow rises above the trigger threshold, the patient's spontaneous breathing effort sets the trigger and cycle moments. The cycle threshold is a generally increasing function of flow rate to time within one breath. Different temporary breathing rate targets have different cycling threshold functions, making cycling easier as the patient's breathing rate approaches the temporary breathing rate target. Similarly, the trigger threshold is a generally decreasing function of flow rate versus time within a breath. Different temporary breathing rate targets have different trigger threshold functions, making triggering easier as the patient's breathing rate approaches the temporary breathing rate target.

[0367] As an additional measure to extend the patient's breathing time Ttot and thereby slow the breathing rate, if the patient's breathing rate is greater than the temporary breathing rate target, the pressure support A is increased. This tends to result in an increase in tidal volume, thereby slowing the breathing rate in order to maintain constant ventilation. The magnitude of the increase in pressure support can be a function of the difference between the temporary breathing rate target and the patient's current breathing rate. The temporary breathing rate target can be periodically reduced in response to the patient's breathing rate slowing toward the current temporary breathing rate target until an optimal breathing rate is reached. An example of an optimal breathing rate is 6 breaths per minute. A sudden increase in the spontaneous breathing rate (such as occurs during arousal) will cause the process of reducing the temporary breathing rate target to be suspended, and will cause the paced breathing to begin again after a predetermined interval.

[0368] Some embodiments of paced breathing can provide a confirmation signal that indicates to the patient when the patient reaches an optimal breathing rate in a manner that does not disturb the bed partner. In such an embodiment, in order to help the patient enter or return to sleep, the accompanying non-disturbing partner confirmation signal can be non-visual and non-auditory, such as via a temporary modification to the treatment pressure Pt. In one instance, a barely discernible soft pressure "bump" is added to the treatment pressure Pt, the target inspiratory time tgtTi, and the target expiratory time tgtTe. Another example is pressure oscillations delivered within the patient interface 3000 via an air circuit at subsonic frequencies. Such pressure oscillations are delivered at an amplitude that can be sensed by facial mechanoreceptors but not heard.

[0369] Pace breathing can be combined with biofeedback matched to a temporary breathing rate target to further improve its effectiveness in slowing breathing. The biofeedback can take the form of visual or auditory, such as a calming scene visualization (e.g., a flower blooming or a backlight with color changes) or a quiet sound (e.g., waves), which can further promote the patient's breathing to slow to the temporary breathing rate target. The biofeedback can be provided via a local external device 4288, which communicates with the RPT device 4000 via a local network 4284. A local external device 4288 suitable for this purpose can be a personal computer, a "smart phone", a tablet computer, a projector, a "smart watch", a network television, or "smart glasses".

[0370] Effective adaptation therapy can also be used as a regular daytime "sedation" treatment for awake patients, while conditioning the patient and producing the benefits of sedation itself. Effective adaptation therapy can also serve as a relaxing prelude to pressure support ventilation therapy, and / or if awakening occurs during pressure support ventilation therapy, it may also be useful for SDB patients with insomnia as a sedation measure. In such an embodiment, adaptation therapy can be called for a predetermined duration (such as 30 minutes) that is long enough for the patient to enter or return to sleep. Alternatively, adaptation therapy can be terminated and pressure support ventilation therapy can be started once the sleep state algorithm 4328 determines that the patient has fallen asleep. Pressure support ventilation therapy can be terminated and adaptation therapy can be restarted once the sleep state algorithm 4328 determines that the patient has awakened.

[0371] A further alternative is for the RPT device 4000 to terminate the adaptation therapy and begin pressure support ventilation therapy upon receiving a command from the patient 1000. In one embodiment of this alternative, the command is issued by activating a manual control that forms part of the user input device 4220 of the RPT device 4000. In other embodiments of this alternative, the command may be a sound uttered by the patient, such as a mouth sound (e.g., a speech sound or a hum), a clap, or a click. An audio sensor for receiving such a command may form part of the transducer 4270 of the RPT device 4000. Alternatively, the audio sensor may be located on a local external device 4288 that communicates with the RPT device 4000 via a local network 4284. In a further embodiment, the command may be a voluntary breathing action or breathing pattern of the patient sensed via the transducer 4270, with less disruption to the patient's relaxation. Such breathing maneuvers may be, for example, a large sigh, a brief apnea / hypopnea, a series of brief apneas / hypopneas, or repeated rapid periodic bursts of inspiration / expiration in an incoherent manner, etc.

[0372] 8.8 Glossary

[0373] For purposes of this technology disclosure, in some forms of the technology, one or more of the following definitions may apply. In other forms of the technology, alternative definitions may apply.

[0374] 8.8.1 General

[0375] Air: In some forms of the present technology, air may refer to atmospheric air, and in other forms of the present technology, air may refer to some other combination of breathable gases, such as an oxygen-enriched atmosphere.

[0376] Respiratory Pressure Therapy (RPT): The application of a supply of air to the entrance of the airways at a therapeutic pressure that is usually positive relative to atmosphere.

[0377] Continuous Positive Airway Pressure (CPAP) Therapy: A respiratory pressure therapy in which the therapy pressure is approximately constant over the patient's breathing cycle. In some forms of CPAP therapy, the pressure at the airway entrance will be slightly higher during exhalation and slightly lower during inspiration. In some forms, the pressure will vary between the patient's breathing cycles, for example increasing in response to detecting an indication of partial upper airway obstruction, and decreasing in the absence of an indication of partial upper airway obstruction.

[0378] Automatic Positive Airway Pressure (APAP) Therapy: CPAP therapy in which the therapy pressure is automatically adjustable, for example from breath to breath (between minimum and maximum limits), depending on the presence or absence of an indication of an SDB event.

[0379] Insomnia: Problems falling asleep and staying asleep or non-restorative sleep that lasts for more than one month and results in functional impairment. Two types of insomnia are observed:

[0380] (i) Sleep-onset insomnia: difficulty falling asleep;

[0381] (ii) Sleep maintenance insomnia: frequent awakenings during the night or early awakenings.

[0382] Hyperarousal: A state of increased psychological and physiological tension, with consequences such as reduced pain tolerance, anxiety, exaggerated startle response, insomnia, fatigue, and intensified personality traits.

[0383] Post-traumatic stress disorder (PTSD): The development of characteristic symptoms following exposure to an extreme traumatic stressor or event. Characteristic symptoms include persistent re-experiencing of the traumatic event (flashbacks), persistent avoidance of trauma-related stimuli, and persistent symptoms of increased arousal. All symptoms must persist for more than one month and result in clinically significant distress or impaired functioning. Post-traumatic stress disorder is common, usually does not resolve without intervention, and results in high levels of functional impairment and health care costs. Violent crimes, including rape and physical assault, combat exposure, and natural disasters are examples of traumatic events that may involve threats to the integrity of oneself or others and may be accompanied by intense fear, helplessness, or terror. Community prevalence estimates for PTSD vary from 1% to 10%, with higher estimates reported in victims of interpersonal violence (20% to 30%) and combat veterans (15% to 30%).

[0384] Persistent: Continue with treatment.

[0385] Compliant: Continuing treatment for an extended period of time.

[0386] 8.8.2 Respiratory cycle

[0387] Apnea: According to some definitions, apnea has occurred when flow drops below a predetermined threshold for a period of time (e.g., 10 seconds). Obstructive apnea has occurred when some obstruction of the airway does not allow air to flow despite the patient's efforts. Central apnea has occurred when apnea is detected due to a decrease or absence of respiratory effort despite a patent airway. Mixed apnea has occurred when a decrease or absence of respiratory effort occurs simultaneously with an obstructed airway.

[0388] Respiratory Rate: The rate at which a patient breathes spontaneously, usually measured in breaths per minute.

[0389] Duty cycle: The ratio of inspiratory time (Ti) to total breathing time (Ttot).

[0390] Effort (Breathing): The work performed by a spontaneously breathing person trying to breathe.

[0391] Expiratory portion of the respiratory cycle: the period from the start of expiratory flow to the start of inspiratory flow.

[0392] Flow Limitation: A state of affairs in a patient's breathing in which an increase in the patient's effort does not result in a corresponding increase in flow rate. In cases where flow limitation occurs during the inspiratory portion of the breathing cycle, it may be described as inspiratory flow limitation. In cases where flow limitation occurs during the expiratory portion of the breathing cycle, it may be described as expiratory flow limitation.

[0393] Types of flow-limited inspiratory waveforms:

[0394] (i) Flat: Having a rise followed by a relatively flat portion, followed by a fall.

[0395] (ii) M-shaped: having two local peaks, one at the leading edge and one at the trailing edge, and a relatively flat portion between the two peaks.

[0396] (iii) Chair-shaped: having a single local peak at the leading edge followed by a relatively flat section.

[0397] (iv) Inverse chair-shaped: having a relatively flat portion followed by a single local peak located at the trailing edge.

[0398] Hypopnea: According to some definitions, a hypopnea is a decrease in flow rather than a cessation of flow. In one form, a hypopnea occurs when a decrease in flow below a threshold persists for a period of time. Central hypopnea occurs when a hypopnea is detected due to a decrease in respiratory effort. In one form in adults, any of the following may be considered a hypopnea:

[0399] (i) The patient's respiration decreases by 30% for at least 10 seconds with an associated 4% desaturation; or

[0400] (ii) The patient has a decrease in breathing (but less than 50%) lasting at least 10 seconds with an associated desaturation or arousal of at least 3%.

[0401] Hyperpnea: Increased air flow to above normal levels.

[0402] Inspiratory portion of the breathing cycle: The period from the start of the inspiratory flow to the start of the expiratory flow is considered the inspiratory portion of the breathing cycle.

[0403]

[00136] Patency (airway): The degree to which an airway is opened or the degree to which an airway is open. A patent airway is open. Airway patency may be quantified, for example with a value of one (1) for open and a value of zero (0) for closed (obstructed).

[0404] Positive End-Expiratory Pressure (PEEP): The pressure above atmospheric pressure that exists in the lungs at the end of exhalation.

[0405] Peak flow rate (Qpeak): The maximum value of the flow during the inspiratory portion of the respiratory airflow waveform.

[0406] Respiratory disturbance index (RDI): apnea-hypopnea index plus RERA index.

[0407] Respiratory event-related arousal (RERA): A respiratory sequence lasting at least 10 seconds characterized by an arousal from sleep caused by an increase in respiratory effort or a smoothing of the inspiratory portion of the flow waveform when the respiratory sequence does not meet the criteria for apnea or hypopnea.

[0408] Respiratory flow rate, patient airflow rate, respiratory airflow rate (Qr): These synonymous terms may be understood to refer to the RPT device's estimate of the respiratory airflow rate, as opposed to the "true respiratory flow rate" or "true breathing air flow rate," which is the actual respiratory flow rate experienced by the patient and is typically expressed in liters per minute.

[0409] Tidal volume (Vt): The volume of air inspired or exhaled during normal breathing when no extra effort is exerted.

[0410] Inspiratory (inhalation) time (Ti): The duration of the inspiratory portion of the respiratory flow waveform.

[0411] Expiratory (exhalation) time (Te): The duration of the exhalation portion of the respiratory flow waveform.

[0412] Respiratory (total) time (Ttot): The total duration between the start of one inspiratory portion of the respiratory flow waveform and the start of the subsequent inspiratory portion of the respiratory flow waveform.

[0413] Typical recent ventilation: the value around which recent values ​​of ventilation Vent tend to cluster within some predetermined time range, that is, a measure of the central tendency of recent values ​​of ventilation.

[0414] Upper airway obstruction (UAO): includes both partial and total upper airway obstruction. This can be associated with a state of flow limitation, where the flow rate increases only slightly or can even decrease as the pressure difference in the upper airway increases (Starling resistor behavior).

[0415] Upper Airway Resistance Syndrome (UARS): A straightforward condition of UARS includes all three of the following criteria: (1) increased esophageal pressure (respiratory effort) deviation; (2) associated with EEG (electroencephalographic) arousals; and (3) with objective criteria of excessive sleepiness. UARS is not generally considered a distinct syndrome, but is instead lumped under the category of respiratory effort-related arousals (RERA).

[0416] Ventilation (Vent): A measurement of the total amount of gas exchanged by a patient's respiratory system. Measurements of ventilation may include either or both of inspiratory and expiratory flow (per unit time). When expressed as volume per minute, this quantity is often referred to as "minute ventilation". Minute ventilation is sometimes given simply as volume, and is understood to be the volume per minute.

[0417] 8.8.3 RPT device parameters

[0418] Flow rate (or flow): volume (or mass) of air delivered per unit time. Flow rate can refer to an instantaneous quantity. Although flow rate and ventilation have the same scale of volume or mass per unit time, flow rate is measured in a much shorter time period. In some cases, references to flow rate will be references to scalar quantities, i.e. quantities with only magnitude. In other cases, references to flow rate will be references to vector quantities, i.e. quantities with both magnitude and direction. In the case where it is referred to as a signed quantity, the flow rate can be nominally positive for the inspiratory portion of the patient's respiratory cycle, and therefore it can be nominally negative for the expiratory portion of the patient's respiratory cycle. The flow rate will be given with the symbol Q. The total flow rate (Qt) is the flow rate at which air leaves the RPT device. The exhaust flow rate (Qv) is the flow rate at which air leaves the vent to allow exhaled gas to wash out. The leakage flow rate (Ql) is the flow rate of leakage from the patient interface system or elsewhere. The respiratory flow rate (Qr) is the flow rate of air received into the patient's respiratory system.

[0419] Leak: Unexpected flow of air. In one example, a leak may occur due to an incomplete seal between the mask and the patient's face. In another example, a leak may occur in the swivel elbow to the surrounding environment.

[0420] Pressure: Force per unit area. Pressure can be measured in a range of units, including cmH2O, gf / cm 2 , hectopascal. 1cmH2O is equal to 1g-f / cm 2 and is approximately 0.98 hectopascals. In this specification, unless otherwise specified, pressure is given in cmH2O. The pressure in the patient interface is given with the symbol Pm, while the treatment pressure represents the target value achieved by the mask pressure Pm at the current moment in time and is given with the symbol Pt.

[0421] 8.8.4 Terminology used for ventilators

[0422] Adaptive servo ventilator (ASV): A servo ventilator with a variable rather than fixed target ventilation. The variable target ventilation may be derived from some characteristics of the patient, such as the patient's breathing characteristics.

[0423] Backup Rate: A parameter of a ventilator that determines the minimum rate of breaths (usually in breaths per minute) that the ventilator will deliver to the patient if not otherwise triggered by spontaneous breathing effort.

[0424] Cyclic: The termination of the inspiratory phase of a ventilator. When a ventilator is delivering a breath to a spontaneously breathing patient, at the end of the inspiratory portion of the respiratory cycle, the ventilator cycles to stop delivering breaths.

[0425] Expiratory Positive Airway Pressure (EPAP): The base pressure to which intra-breath varying pressures are added to produce the desired mask pressure that the ventilator will attempt to achieve at a given time.

[0426] End Expiratory Pressure (EEP): The desired mask pressure that the ventilator will attempt to achieve at the end of the expiratory portion of a breath. If the pressure waveform template II (Φ) is zero at the end of exhalation, i.e., II (Φ) = 0 when Φ = 1 revolution, EEP equals EPAP.

[0427] Inspiratory Positive Airway Pressure (IPAP): The maximum desired mask pressure that the ventilator will attempt to achieve during the inspiratory portion of a breath.

[0428] Pressure Support: A number indicating the pressure during ventilator inspiration increases with the pressure during ventilator expiration, which usually means the difference in pressure between the maximum during inspiration and the base pressure (e.g., PS = IPAP-EPAP). In some cases, pressure support means the difference in the ventilator target to be achieved rather than what is actually achieved.

[0429] Servomotor: A ventilator that measures patient ventilation, has a target ventilation and adjusts the level of pressure support to bring the patient's ventilation to the target ventilation.

[0430] Spontaneous / Timed (S / T): A mode of a ventilator or other device that attempts to detect the onset of a breath in a spontaneously breathing patient. However, if the device cannot detect a breath within a predetermined time period, the device will automatically begin delivering a breath.

[0431] Volatility: A term equivalent to Pressure Support.

[0432] Triggered: When a ventilator delivers breathable air to a spontaneously breathing patient, it is considered to be triggered to do so at the beginning of the breathing portion of the breathing cycle by the patient's effort.

[0433] Typical recent ventilation: Typical recent ventilation Vtyp is the value around which recent measurements of ventilation tend to cluster over some predetermined time range, ie, a measure of the central tendency of the measurements of ventilation in recent history.

[0434] Ventilator: A mechanical device that provides pressure support to a patient to perform some or all of the work of breathing.

[0435] 8.8.5 Anatomy of the respiratory system

[0436] Diaphragm: A sheet of muscle that stretches across the base of the rib cage. The diaphragm separates the chest cavity, which contains the heart, lungs, and ribs, from the abdominal cavity. When the diaphragm contracts, the chest cavity increases in volume and draws air into the lungs.

[0437] Larynx: The larynx or larynx houses the vocal cords and connects the lower part of the pharynx (hypopharynx) to the trachea.

[0438] Lung: The respiratory organ of humans. The ductal region of the lung contains the trachea, bronchi, bronchioles, and terminal bronchioles. The respiratory region contains the respiratory bronchioles, alveolar ducts, and alveoli.

[0439] Nasal Cavity: The nasal cavity (or nasal fossa) is the large air-filled space above and behind the nose in the middle of the face. The nasal cavity is divided into two parts by a vertical wing called the nasal septum. On the sides of the nasal cavity are three long horizontal necks called the conchae (singular "concha") or turbinates. Towards the front of the nasal cavity is the nose, while the back fuses into the nasopharynx via the choanae.

[0440] Pharynx: The part of the throat that lies directly below (under) the nasal cavity and above the esophagus and larynx. The pharynx is conventionally divided into three parts: the nasopharynx (epipharynx) (the nasal part of the pharynx), the oropharynx (mesopharynx) (the oral part of the pharynx), and the hypopharynx (hypopharynx).

[0441] 8.8.6 Mathematical terms

[0442] Fuzzy logic is used in many places in this technology. The following function is used to represent a fuzzy membership function, which outputs a "fuzzy truth value" in the range [0,1], with 0 representing fuzzy false and 1 representing fuzzy true:

[0443] FuzzyMember(ActualQuantity,ReferenceQuantity1,FuzzyTruthValueAtReferenceQuantity1,ReferenceQuantity2,FuzzyTruthValueAtReferenceQuantity2,...,ReferenceQuantityN,FuzzyTruthValueAtReferenceQuantityN)

[0444] The fuzzy membership function is defined as

[0445]

[0446] in

[0447]

[0448] f j is a fuzzy truth value, and x and x j is a real number.

[0449] In addition to these f k Function "Interp" is defined to be the same as "FuzzyMember", except that the values ​​are interpreted as real numbers rather than fuzzy truth values.

[0450] The fuzzy "OR" of fuzzy truth values ​​is the maximum of these values; the fuzzy "AND" of fuzzy truth values ​​is the minimum of these values. These will be represented by the functions FuzzyOr and FuzzyAnd of two or more fuzzy truth values. It should be understood that other typical definitions of these fuzzy operations will work similarly in the present technology.

[0451] “Exponential decay towards zero” with time constant τ means that during any decay period starting at time t=T, the value of the decay amount V is given by .

[0452]

[0453] 8.9 Other notes

[0454] A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever.

[0455] Unless the context clearly dictates otherwise and where a range of values ​​is provided, it is understood that each intervening value between the upper and lower limits of the range to one-tenth of the unit of the lower limit, and any other stated or intervening value in the stated range, is encompassed within the present technology. The upper and lower limits of these intervening ranges may be independently included in the intervening ranges, which are also encompassed within the present technology, subject to any explicitly excluded limitations in the stated ranges. Where the stated range includes one or both of these limitations, ranges excluding either or both of these included limitations are also included in the present technology.

[0456] Furthermore, where a value or values ​​are set forth herein as part of implementation of the present technology, it should be understood that such values ​​may be approximated unless otherwise indicated and that such values ​​may be used to any suitable significant figures to the extent that the practical implementation of the technology may permit or require it.

[0457] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this technology belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present technology, a limited number of exemplary methods and materials are described herein.

[0458] When a particular material is determined to be preferred for use in forming a component, obvious alternative materials with similar properties may be used as substitutes. In addition, unless otherwise specified, any and all components described herein should be understood to be capable of being manufactured, and likewise can be manufactured together or separately.

[0459] It must be noted that as used herein and in the appended claims, the singular forms "a," "an," and "the" include their plural counterparts unless the context clearly dictates otherwise.

[0460] All publications mentioned herein are incorporated by reference to disclose and describe methods and / or materials as the themes of these publications. Only the disclosure before the filing date of the present application provides the publications discussed herein. Anything herein shall not be construed as admitting that the present technology has no right to publish such publications in advance by means of previous inventions. And then, the date of the publication provided may be different from the actual publication date, and this may need to be confirmed independently.

[0461] These terms "comprises" and "comprising" should be interpreted as referring to elements, components or steps in a non-exclusive manner, indicating that the referred elements, components or steps may be present, utilized, or combined with other elements, components or steps that are not explicitly referred to.

[0462] The subject headings used in the detailed description are included only for the convenience of the reader's reference and should not be used to limit the subject matter found in the entire disclosure or claims. The subject headings should not be used to interpret the scope of the claims or claim limitations.

[0463] Although the present technology has been described with reference to specific embodiments, it should be understood that these embodiments are merely exemplary illustrations of the principles and applications of the present technology. In some cases, terms and symbols may imply specific details that are not required for practicing the present technology. For example, although the terms "first" and "second" may be used, unless otherwise specified, they are not intended to represent any order but may be used to distinguish between different elements. In addition, although the process steps in a set of methods can be described or illustrated in order, such an ordering is not required. Those skilled in the art will recognize that such an ordering can be modified and / or various aspects thereof can be performed simultaneously or even synchronously.

[0464] It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present technology.

[0465] 8.10 Reference marking table

[0466] Patient 1000

[0467] Patient Interface 3000

[0468] Sealed molding structure 3100

[0469] Booster Room 3200

[0470] Structure 3300

[0471] Vent 3400

[0472] Connect to port 3600

[0473] Forehead support 3700

[0474] RPT Device 4000

[0475] External housing 4010

[0476] Upper part 4012

[0477] Section 4014

[0478] Plate 4015

[0479] Base frame 4016

[0480] Handle 4018

[0481] Pneumatic block 4020

[0482] Pneumatic components 4100

[0483] Air filter 4110

[0484] Inlet air filter 4112

[0485] Outlet air filter 4114

[0486] Muffler 4120

[0487] Inlet muffler 4122

[0488] Outlet muffler 4124

[0489] Pressure Generator 4140

[0490] Blower 4142

[0491] Motor 4144

[0492] Anti-overflow check valve 4160

[0493] Air circuit 4170

[0494] Supplemental oxygen 4180

[0495] Electrical Components 4200

[0496] PCBA 4202

[0497] Power supply 4210

[0498] Input device 4220

[0499] Central Controller 4230

[0500] Clock 4232

[0501] Therapy Device Controller 4240

[0502] Protection circuit 4250

[0503] Memory 4260

[0504] Transducer 4270

[0505] Pressure Sensor 4272

[0506] Flow rate sensor 4274

[0507] Motor Speed ​​Transducer 4276

[0508] Data Communication Interface 4280

[0509] Remote external communication network 4282

[0510] Local network 4284

[0511] Remote External Device 4286

[0512] Local external device 4288

[0513] Output device 4290

[0514] Display Driver 4292

[0515] Display 4294

[0516] Algorithm 4300

[0517] Preprocessing module 4310

[0518] Pressure Compensation Algorithm 4312

[0519] Vent Flow Rate Estimation Algorithm 4314

[0520] Leakage flow rate estimation algorithm 4316

[0521] Respiratory flow rate estimation algorithm 4318

[0522] Interference Detection Algorithm 4319

[0523] Therapy Engine Module 4320

[0524] Phase Determination Algorithm 4321

[0525] Waveform determination 4322

[0526] Ventilation Determination Algorithm 4323

[0527] Inspiratory Flow Limitation Determination Algorithm 4324

[0528] Apnea / Hypopnea Determination Algorithm 4325

[0529] Snoring Determination Algorithm 4326

[0530] Target ventilation determination algorithm 4327

[0531] Sleep state determination algorithm 4328

[0532] Therapy parameter determination algorithm 4329

[0533] Therapy Control Algorithm 4330

[0534] Humidifier 5000

[0535] Method 7000

[0536] Step 7010

[0537] Step 7020

[0538] Step 7030

[0539] Step 7040

[0540] Step 7050

[0541] Process 7059

[0542] Step 7060

[0543] Step 7070

[0544] Example Histogram 9000

[0545] Process 10000

[0546] Step 10010

[0547] Step 10020

[0548] Step 10030

[0549] Process 11000

[0550] Step 11010

[0551] Step 11020

[0552] 9 References cited

[0553] Krakow B, Ulibarri VA, Romero EA. Patients With Treatment-Resistant Insomnia Taking Nightly Prescription Medications for Sleep: A Retrospective Assessment of Diagnostic and Treatment Variables. Journal of Clinical Psychiatry Primary Care Companion, 2010: 12(4).

Claims

1. A device for treating SDB-associated hyperarousal, comprising: a pressure generator configured to deliver a flow of air to the airway of the patient at a controlled therapeutic pressure above atmospheric pressure via a patient interface on the air circuit; a transducer for generating a signal related to a characteristic of the air flow; and A controller configured to: determining the patient's voluntary breathing effort or breathing pattern with the aid of a signal from the transducer; controlling the therapeutic pressure of the air flow so as to apply paced breathing to the airway of the patient, controlling providing biofeedback to the patient, wherein the biofeedback matches a temporary breathing rate target for the paced breathing; as well as Responsive to a determination of a voluntary breathing effort or breathing pattern of the patient, the biofeedback is terminated.

2. The apparatus of claim 1 further comprising a user input device comprising a manual control.

3. The apparatus of claim 2, wherein the controller is further configured to terminate the paced breathing and the biofeedback when the manual control is activated. The apparatus of claim 1 , further comprising an audio sensor.

5. The apparatus of claim 4, wherein the controller is further configured to terminate the paced breathing and the biofeedback when the audio sensor detects a predetermined sound.

6. The apparatus of claim 1, further comprising a data communication interface through which the controller is configured to communicate with a local external device.

7. The apparatus of claim 6, wherein the controller is configured to control the local external device to provide the biofeedback to the patient.

8. The apparatus of claim 6, wherein the controller is further configured to receive an audio signal from the local external device.

9. The apparatus of claim 8, wherein the controller is further configured to terminate the paced breathing and the biofeedback upon detecting a predetermined sound in the audio signal.

10. The apparatus of any one of claims 1 to 9, wherein the controller is configured to terminate the paced breathing and the biofeedback in response to a determination of a voluntary breathing effort or breathing pattern of the patient.

11. A computer readable storage medium having instructions stored thereon that adapt a patient to pressure support ventilation therapy, the instructions, when executed by a controller of a respiratory pressure therapy device configured for pressure support ventilation therapy, cause the controller to: controlling a pressure generator of the respiratory pressure therapy device to apply a constant-rate breath to the patient's airway, controlling generation of biofeedback to be provided to the patient, wherein the biofeedback matches a temporary breathing rate target for the paced breathing; and Responsive to a determination of a voluntary breathing effort or breathing pattern of the patient, the biofeedback is terminated.

12. The computer-readable storage medium of claim 11, wherein the biofeedback is one or more of an auditory and a visual modality.

13. The computer-readable storage medium of any one of claims 11 to 12, wherein execution of the instructions causes the controller to terminate the paced breathing upon receiving a command from the patient.

14. The computer-readable storage medium of claim 13, wherein the command is one or more of activation of a manual control or a sound uttered by a patient.

15. The computer-readable storage medium of claim 13, wherein the command is the voluntary breathing effort or another voluntary breathing effort of the patient.

16. The computer readable storage medium of claim 11, wherein execution of the instructions causes the controller to receive sensor data from a transducer representing a voluntary breathing effort or breathing pattern of the patient.

17. The computer readable storage medium of claim 11, wherein execution of the instructions causes the controller to terminate the paced breathing and the biofeedback in response to a determination of a voluntary breathing effort or breathing pattern of the patient.

18. A computer-readable storage medium having stored thereon instructions for controlling a servo-ventilator to treat SDB associated with hyperarousal disorder, wherein the instructions, when executed by a controller of the servo-ventilator, cause the controller to: determining or identifying a measure of patient ventilation, wherein the measure of patient ventilation is a measure of the total amount of gas exchanged by the patient's respiratory system; adjusting a level of pressure support so that a measure of the patient's ventilation reaches a target ventilation, wherein the pressure support is the pressure difference between a maximum value during inspiration and an expiratory positive airway pressure; controlling a servo ventilator to servo-ventilate the patient using a servo ventilation control gain value multiplied by a difference between a measured value of the patient's ventilation and a target ventilation, and determining a sleep state of the patient, The servo-ventilation control gain value is varied according to the determined sleep state.

19. The computer-readable storage medium of claim 18, wherein the servo-ventilation control gain value is relatively low when the patient is determined to be in an awake state, and the servo-ventilation control gain value is relatively high when the patient is determined to be in a sleeping state.

20. The computer-readable storage medium according to claim 18 or 19, wherein the servo-ventilation control gain value (G) is defined as: G = sleep state weight × G0, wherein the sleep state weight is a sleep state weight based on the determined sleep state of the patient, and G0 is a fixed value of the controller gain value.

21. A device for treating SDB-associated hyperarousal, comprising: a pressure generator configured to deliver a flow of air to the airway of a patient at a controlled therapeutic pressure via a patient interface on the air circuit, wherein the controlled therapeutic pressure is above atmospheric pressure; and A controller configured to: determining or identifying a measure of patient ventilation of the patient, wherein the measure of patient ventilation is a measure of the total amount of gas exchanged by the patient's respiratory system; adjusting a level of pressure support so that a measure of the patient's ventilation reaches a target ventilation, wherein the pressure support is the pressure difference between a maximum value during inspiration and an expiratory positive airway pressure; controlling the controllable therapeutic pressure of the air flow to servo-ventilate the patient using a servo-ventilation control gain value multiplied by a difference between a measured value of patient ventilation and a target ventilation; as well as A sleep state of the patient is determined, wherein the servo-ventilation control gain value is varied according to the determined sleep state.

22. The apparatus according to claim 21, wherein when it is determined that the patient is in an awake state, the servo-ventilation control gain value is relatively low, and when it is determined that the patient is in a sleeping state, the servo-ventilation control gain value is relatively high.

23. The apparatus according to claim 21 or 22, wherein the servo-ventilation control gain value (G) is defined as: G = sleep state weight × G0, wherein the sleep state weight is a sleep state weight based on the determined sleep state of the patient, and G0 is a fixed value of the controller gain value.

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