Methods and systems of determining heart rate

Abstract

Techniques for determining the heart rate of a sleeping patient are provided. An IMU obtains sensor data, and the data is filtered using one or more high pass or low pass filters. The components of the data are combined to generate a magnitude vector. Peaks are detected within the filtered signal, and a heart rate is calculated based on the detected peaks.

Description

METHODS AND SYSTEMS OF DETERMINING HEART RATE1 CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application No. 63 / 733,826, filed December 13, 2024, the entire contents being hereby incorporated by reference. The entire contents of PCT / AU2017 / 050859 are hereby incorporated by reference, in its entirety.2 BACKGROUND OF THE TECHNOLOGY2.1 FIELD OF THE TECHNOLOGY

[0002] The present technology relates to one or more of the screening, diagnosis, monitoring, treatment, prevention and amelioration of respiratory-related disorders. The present technology relates to medical devices or apparatus, and their use. The present technology relates to determining cardiac parameters (e.g., heart rate) of a patient using inertial measurement units, such as a gyro sensor or the like.2.2 DESCRIPTION OF THE RELATED ART2.2.1 Human Respiratory System and its Disorders

[0003] The respiratory system of the body facilitates gas exchange. The nose and mouth form the entrance to the airways of a patient.

[0004] The airways include a series of branching tubes, which become narrower, shorter and more numerous as they penetrate deeper into the lung. The prime function of the lung is gas exchange, allowing oxygen to move from the inhaled air into the venous blood and carbon dioxide to move in the opposite direction. The trachea divides into right and left main bronchi, which further divide eventually into terminal bronchioles. The bronchi make up the conducting airways, and do not take part in gas exchange. Further divisions of the airways lead to the respiratory bronchioles, and eventually to the alveoli. The alveolated region of the lung is where the gas exchange takes place, and is referred to as the respiratory zone.

[0005] A range of respiratory disorders exist. Certain disorders may be characterised by particular events, e.g., apneas, hypopneas, and hyperpneas.

[0006] Examples of respiratory disorders include Obstructive Sleep Apnea (OSA), Cheyne-Stokes Respiration (CSR), respiratory insufficiency, Obesity Hypoventilation Syndrome (OHS), Chronic Obstructive Pulmonary Disease (COPD), Neuromuscular Disease (NMD) and Chest wall disorders.

[0007] Heart failure is a relatively common and severe clinical disorder, characterised by the inability of the heart to keep up with the oxygen demands of the body. Management of heart failure is a significant challenge to modem healthcare systems due to its high prevalence and severity. Heart failure is a chronic disorder, which is progressive in nature. The progression of heart failure is often characterised as relatively stable over long periods of time (albeit with reduced cardiovascular function) punctuated by episodes of an acute nature. In these acute episodes, the patient experiences worsening of symptoms such as dyspnea (difficulty breathing), gallop rhythms, increased jugular venous pressure, and orthopnea. This is typically accompanied by overt congestion (which is the buildup of fluid in the pulmonary cavity). This excess fluid often leads to measurable weight gain of several kilograms. In many cases, however, by the time overt congestion has occurred, there are limited options for the doctor to help restabilize the patients, and in many cases the patient requires hospitalization. In extreme cases, without timely treatment, the patient may undergo acute decompensated heart failure (ADHF) events.

[0008] Respiratory failure is an umbrella term for respiratory disorders in which the lungs are unable to inspire sufficient oxygen or exhale sufficient CO2 to meet the patient’s needs. Respiratory failure may encompass some or all of the following disorders. A patient with respiratory insufficiency (a form of respiratory failure) may experience abnormal shortness of breath on exercise.

[0009] Chronic Obstructive Pulmonary Disease (COPD) encompasses any of a group of lower airway diseases that have certain characteristics in common. These include increased resistance to air movement, extended expiratory phase of respiration, and loss of the normal elasticity of the lung. Examples of COPD are emphysema and chronic bronchitis. COPD is caused by chronic tobacco smoking (primary risk factor), occupational exposures, air pollution and genetic factors. Symptoms include: dyspnea on exertion, chronic cough and sputum production.2.2.2 Therapies

[0010] Various respiratory therapies, such as Continuous Positive Airway Pressure (CPAP) therapy, Non-invasive ventilation (NIV), Invasive ventilation (IV), and High Flow Therapy (HFT) have been used to treat one or more of the above respiratory disorders.

[0011] Respiratory pressure therapy is the application of a supply of air to an entrance to the airways at a controlled target pressure that is nominally positive with respect to atmosphere throughout the patient’s breathing cycle (in contrast to negative pressure therapies such as the tank ventilator or cuirass).

[0012] 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 may 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 may be voluntary, and hence patients may elect not to comply with therapy if they find devices used to provide such therapy one or more of: uncomfortable, difficult to use, expensive and aesthetically unappealing.

[0013] Non-invasive ventilation (NIV) provides ventilatory support to a patient through the upper airways to assist the patient breathing and / or maintain adequate oxygen levels in the body by doing some or all of the work of breathing. The ventilatory support is provided via a non-invasive patient interface. NIV has been used to treat CSR and respiratory failure, in forms such as OHS, COPD, NMD and Chest Wall disorders. In some forms, the comfort and effectiveness of these therapies may be improved.2.2.3 Respiratory Therapy Systems

[0014] These respiratory therapies may be provided by a respiratory therapy system or device. Such systems and devices may also be used to screen, diagnose, or monitor a condition without treating it.

[0015] A respiratory therapy system may comprise a Respiratory Pressure Therapy Device (RPT device), an air circuit, a humidifier, a patient interface, an oxygen source, and / or data management.2.2.3.1 Patient Interface

[0016] A patient interface may be used to interface respiratory equipment to its wearer, for example by providing a flow of air to an entrance to the airways. The flow of air may be provided via a mask to the nose and / or mouth, a tube to the mouth or a tracheostomy tube to the trachea of a patient. Depending upon the therapy to be applied, the patient interface may form a seal, e.g., with a region of the patient's face, to facilitate the delivery of gas at a pressure at sufficient variance with ambientpressure to effect therapy, e.g., at a positive pressure of about 10 cmPFO relative to ambient pressure. For other forms of therapy, such as the delivery of oxygen, the patient interface may not include a seal sufficient to facilitate delivery to the airways of a supply of gas at a positive pressure of about 10 cmHiO. For flow therapies such as nasal HFT, the patient interface is configured to insufflate the nares but specifically to avoid a complete seal. One example of such a patient interface is a nasal cannula.2.2.3.2 Respiratory Pressure Therapy (RPT) Device

[0017] A respiratory pressure therapy (RPT) device may be used individually or as part of a system to deliver one or more of a number of therapies described above, such as by operating the device to generate a flow of air for delivery to an interface to the airways. The flow of air may be pressure-controlled (for respiratory pressure therapies) or flow-controlled (for flow therapies such as HFT). Thus, RPT devices may also act as flow therapy devices. Examples of RPT devices include a CPAP device and a ventilator.2.2.3.3 Air circuit

[0018] An air circuit is a conduit or a tube constructed and arranged to allow, in use, a flow of air to travel between two components of a respiratory therapy system such as the RPT device and the patient interface. In some cases, there may be separate limbs of the air circuit for inhalation and exhalation. In other cases, a single limb air circuit is used for both inhalation and exhalation.2.2.3.4 Humidifier

[0019] Delivery of a flow of air without humidification may cause drying of airways. The use of a humidifier with an RPT device and the patient interface produces humidified gas that minimizes drying of the nasal mucosa and increases patient airway comfort. In addition, in cooler climates, warm air applied generally to the face area in and about the patient interface is more comfortable than cold air.2.2.3.5 Data Management

[0020] There may be clinical reasons to obtain data to determine whether the patient prescribed with respiratory therapy has been “compliant”, e.g. that the patient has used their RPT device according to one or more “compliance rules”. One example of a compliance rule for CPAP therapy is that a patient, in order to be deemed compliant, is required to use the RPT device for at least four hours a night for at least 21 of 30 consecutive days. In order to determine a patient's compliance, a provider of the RPT device, such as a health care provider, may manually obtain data describingthe patient's therapy using the RPT device, calculate the usage over a predetermined time period, and compare with the compliance rule. Once the health care provider has determined that the patient has used their RPT device according to the compliance rule, the health care provider may notify a third party that the patient is compliant.

[0021] There may be other aspects of a patient’s therapy that would benefit from communication of therapy data to a third party or external system.

[0022] Existing processes to communicate and manage such data can be one or more of costly, time-consuming, and error prone.2.2.3.6 Vent technologies

[0023] Some forms of treatment systems may include a vent to allow the washout of exhaled carbon dioxide. The vent may allow a flow of gas from an interior space of a patient interface, e.g., the plenum chamber, to an exterior of the patient interface, e.g., to ambient.2.2.4 Screening, Diagnosis, and Monitoring Systems

[0024] Polysomnography (PSG) is a conventional system for diagnosis and monitoring of cardio-pulmonary disorders, and typically involves expert clinical staff to apply the system. PSG typically involves the placement of 15 to 20 contact sensors on a patient in order to record various bodily signals such as electroencephalography (EEG), electrocardiography (ECG), electrooculograpy (EOG), electromyography (EMG), etc. PSG for sleep disordered breathing has involved two nights of observation of a patient in a clinic, one night of pure diagnosis and a second night of titration of treatment parameters by a clinician. PSG is therefore expensive and inconvenient. In particular, it is unsuitable for home screening / diagnosis / monitoring of sleep disordered breathing.

[0025] Screening and diagnosis generally describe the identification of a condition from its signs and symptoms. Screening typically gives a true / false result indicating whether or not a patient’s SDB is severe enough to warrant further investigation, while diagnosis may result in clinically actionable information. Screening and diagnosis tend to be one-off processes, whereas monitoring the progress of a condition can continue indefinitely. Some screening / diagnosis systems are suitable only for screening / diagnosis, whereas some may also be used for monitoring.

[0026] Clinical experts may be able to screen, diagnose, or monitor patients adequately based on visual observation of PSG signals. However, there are circumstances where a clinical expert may not be available, or a clinical expert may not be affordable. Different clinical experts may disagree on a patient’s condition. In addition, a given clinical expert may apply a different standard at different times.2.2.5 Heart Rate

[0027] A person’s heart rate is a cardiac attribute that relates to how many times the person’s heart beats within a given time period (e.g., a minute). A typical resting heart rate of a person can vary between 60 to 100 beats per minute and may be below or above such values depending on various factors of the person (e.g., if they are exercising, etc.).

[0028] There are a variety of techniques that can be used to measure the heart rate of a person. These include manual measurement that is based on counting the number of times a beat is felt / heard in 6 seconds. This may be accomplished by, for example, taking a pulse at one or more arteries of the body (e.g., the radial or carotid arteries). Other techniques for measuring heart rate include ECG / EKG measurements that generate a signal based on electrical activity of the heart. In some instances, such information can be obtained by a person wearing a strap around their torso to acquire the electrical signals generated by the body. Further techniques include pulse oximetry (e.g., via a finger), laser doppler imaging (e.g., via a person’s eye).

[0029] However, these types of techniques may be costly, time-consuming / burdensome, and / or error prone. For example, manually tracking the heartbeat of a person may be inaccurate. Moreover, if a person is sleeping then such a measurement would likely be performed by another person. And while ECG instruments have shown to accurate in some instances, it can be cumbersome for individuals to acquire heartbeat data every day using such a technique (e.g., as it may require wearing a chest strap). Pulse oximetry also may require a person wearing an additional device in order to acquire the necessary data. In a clinical setting, setting up additional sensors and devices to acquire data can be pursued. However, in a home setting that does not have a on staff clinician, such additional steps (especially if performed on a daily / nightly basis) can be burdensome for individuals.

[0030] Accordingly, it will be appreciated that new and improved techniques, systems, and processes are continually sought after in this and other areas oftechnology. For example, to allow for obtaining a sleeping person’s heart rate in an unobtrusive manner.3 BRIEF SUMMARY OF THE TECHNOLOGY

[0031] The present technology is directed towards providing medical devices used in the screening, diagnosis, monitoring, amelioration, treatment, or prevention of respiratory disorders having one or more of improved comfort, cost, efficacy, ease of use, and manufacturability.

[0032] A first aspect of the present technology relates to apparatuses and / or methods used in the screening, diagnosis, monitoring, amelioration, treatment or prevention of a respiratory disorder.

[0033] An aspect of certain forms of the present technology is to provide methods, systems, and / or devices that provide a determination or estimation of the heart rate of an individual.

[0034] An aspect of certain forms of the present technology is to provide methods, systems, and / or devices that provide one or more sensors (e.g., an IMU) with an air conduit of a RPT system. Such sensors may be electrically connected to, for example, a RPT device of an RPT system.

[0035] An aspect of certain forms of the present technology is to provide methods, systems, and / or devices that use a determination or estimation of the heart rate to: 1) generate sleep metrics and / or display such metrics for a user; and / or 2) control, based on such a determined heart rate, one or more attributes (e.g., pressure) of respiratory sleep therapy for the patient.

[0036] Sleep metrics that may be generated based on or in association with heart rate may include one or more of: 1) determining, based on heart rate data, one or more sleep factors that have influenced heart rate of an individual; 2) generating or selecting, based on heart rate data, a sleep signature that corresponds to the heart rate signal of a patient; 3) determining a resting heart rate of a time period that a patient is sleeping and generating a historical graph of such a determined resting heart rate; 4) generating, based on IMU data, sleep position data of a patient; and 5) generating, based at least in part on heart rate data, a sleep score for a patient.

[0037] An aspect of certain forms of the present technology is to provide methods and / or apparatus that improve the compliance of patients with respiratory therapy.

[0038] The methods, systems, devices and apparatus described may be implemented so as to improve the functionality of a processor, such as a processor of a specific purpose computer, respiratory monitor and / or a respiratory therapy apparatus. Moreover, the described methods, systems, devices and apparatus can provide improvements in the technological field of automated management, monitoring and / or treatment of respiratory conditions, including, for example, sleep disordered breathing.

[0039] Of course, portions of the aspects may form sub-aspects of the present technology. Also, various ones of the sub-aspects and / or aspects may be combined in various manners and also constitute additional aspects or sub-aspects of the present technology.

[0040] Other features of the technology will be apparent from consideration of the information contained in the following detailed description, abstract, drawings and claims.

[0041] The determination of heart rate, particularly in sleeping patients undergoing respiratory therapy, can be challenging. The current state of the art. Conventional techniques, such as manual pulse measurement, electrocardiography (ECG), or pulse oximetry, often require direct physical contact with the patient or the use of cumbersome and intrusive devices, such as chest straps, finger clips, or electrodes. These methods can be uncomfortable, disrupt sleep, and are impractical for continuous or long-term monitoring in a home setting. Additionally, polysomnography (PSG) can be expensive, labor-intensive, and / or unsuitable for routine or home-based use. These limitations hinder the ability to unobtrusively and accurately monitor heart rate during sleep, which is important for assessing sleep quality, detecting sleep-related disorders, and optimizing respiratory therapy.

[0042]

[0043] The techniques discussed herein provide approach for determining heart rate using an inertial measurement unit (IMU) integrated into a respiratory therapy system. Unlike traditional approaches, the described system leverages the IMU's ability to detect micro-movements associated with ballistocardiography (BCG) to unobtrusively monitor cardiac activity. The IMU, strategically positioned within the air circuit or patient interface, captures multi-axis motion data (e.g., X, Y, and Zcomponents) generated by the patient’s physiological movements during sleep. This data is processed using specialized algorithms, including high-pass and low-pass filtering, magnitude vector calculations, and peak detection techniques, to determine heart rate without requiring additional wearable devices or invasive sensors.

[0044]

[0045] The described concept enhances prior approaches by facilitating seamless integration with existing respiratory therapy systems, such as Continuous Positive Airway Pressure (CPAP) devices, while maintaining patient comfort and therapy effectiveness. The system’s capability to unobtrusively monitor heart rate in real-time supports improved sleep analysis, including the generation of sleep metrics, sleep stage identification, and personalized therapy adjustments. Additionally, the application of advanced signal processing techniques enables reliable and precise heart rate detection, even under conditions of noise or patient movement. By addressing the limitations of conventional methods, the described system offers a cost-efficient, user-friendly, and adaptable solution for continuous heart rate monitoring in both clinical and home settings.4 BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The present technology is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings, in which like reference numerals refer to similar elements including:4.1 RESPIRATORY THERAPY SYSTEMS

[0047] Fig. 1 shows a system including a patient 1000 wearing a patient interface 3000 receiving a supply of air at positive pressure from an RPT device 4000. The example patient interface shown in Fig. 1 is in the form of nasal pillows. Air from the RPT device 4000 can be humidified via a humidifier 5000. The air passes along an air circuit 4170 to the patient 1000. A bed partner 1100 is also shown. The patient is sleeping in a supine sleeping position; but may be sleeping in other positions throughout the night.4.2 RESPIRATORY SYSTEM AND FACIAL ANATOMY

[0048] Fig. 2 shows an overview of a human respiratory system including the nasal and oral cavities, the larynx, vocal folds, oesophagus, trachea, bronchus, lung, alveolar sacs, heart and diaphragm.4.3 PATIENT INTERFACE

[0049] Fig. 3 shows a patient interface in the form of a nasal mask in accordance with one form of the present technology.4.4 RPT DEVICE

[0050] Fig. 4A shows an RPT device in accordance with one form of the present technology.

[0051] Fig. 4B is a schematic diagram of the pneumatic path of an RPT device in accordance with one form of the present technology. The directions of upstream and downstream are indicated with reference to the blower and the patient interface. The blower is defined to be upstream of the patient interface and the patient interface is defined to be downstream of the blower, regardless of the actual flow direction at any particular moment. Items which are located within the pneumatic path between the blower and the patient interface are downstream of the blower and upstream of the patient interface.

[0052] Fig. 4C is a schematic diagram of the electrical components of an RPT device in accordance with one form of the present technology.

[0053] Fig. 4D is a schematic diagram of the algorithms implemented in an RPT device in accordance with one form of the present technology.

[0054] Fig. 4E is a flow chart illustrating a method carried out by the therapy engine module of Fig. 4D in accordance with one form of the present technology.4.5 HUMIDIFIER

[0055] Fig. 5A shows an isometric view of a humidifier in accordance with one form of the present technology.

[0056] Fig. 5B shows an isometric view of a humidifier in accordance with one form of the present technology, showing a humidifier reservoir 5110 removed from the humidifier reservoir dock 5130.4.6 BREATHING WAVEFORMS

[0057] Fig. 6 shows a model typical breath waveform of a person while sleeping.4.7 HEART RATE SYSTEMS AND METHODS

[0058] Figure. 7 is a schematic diagram of an example heart rate systemin accordance with one form of the present technology.

[0059] Figures 8A and 8B are cross-sectional diagrams of how an IMU may be provided with an air conduit in accordance with various forms for the present technology.

[0060] Figures 9A and 9B are flow character of example processes for calculating a heartrate according to various forms of the present technology.

[0061] Figures 10A-10H are graphs illustrating the results of different signal processing from the process shown in Figure 9A.

[0062] Figures 11A-1 IB are illustrative graphical user interfaces that show different example implementations for how a heart rate may be displayed according to various forms of the present technology.5 DETAILED DESCRIPTION OF EXAMPLES OF THETECHNOLOGY

[0063] Before the present technology is described in further detail, it is to be understood that the technology is not limited to the particular examples described herein, which may vary. It is also to be understood that the terminology used in this disclosure is for the purpose of describing only the particular examples discussed herein, and is not intended to be limiting.

[0064] The following description is provided in relation to various examples which may share one or more common characteristics and / or features. It is to be understood that one or more features of any one example may be combinable with one or more features of another example or other examples. In addition, any single feature or combination of features in any of the examples may constitute a further example.5.1 THERAPY

[0065] In one form, the present technology comprises a method for treating a respiratory disorder comprising applying positive pressure to the entrance of the airways of a patient 1000.

[0066] In certain examples of the present technology, a supply of air at positive pressure is provided to the nasal passages of the patient via one or both nares.

[0067] In certain examples of the present technology, mouth breathing is limited, restricted or prevented.5.2 RESPIRATORY THERAPY SYSTEMS

[0068] In one form, the present technology comprises a respiratory therapy system for treating a respiratory disorder. The respiratory therapy system may comprise an RPT device 4000 for supplying a flow of air to the patient 1000 via an air circuit 4170 and a patient interface (e.g., 3000 etc.).5.3 PATIENT INTERFACE

[0069] A non-invasive patient interface 3000, such as that shown in Fig. 3, in accordance with one aspect of the present technology comprises the following functional aspects: a seal-forming structure 3100, a plenum chamber 3200, a positioning and stabilising structure 3300, a vent 3400, one form of connection port 3600 for connection to air circuit 4170, and a forehead support 3700. In some forms a functional aspect 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 an entrance to the airways of the patient so as to maintain positive pressure at the entrance(s) to the airways of the patient 1000. The sealed patient interface 3000 is therefore suitable for delivery of positive pressure therapy.

[0070] If a patient interface is unable to comfortably deliver a minimum level of positive pressure to the airways, the patient interface may be unsuitable for respiratory pressure therapy.

[0071] The patient interface 3000 in accordance with one form of the present technology is constructed and arranged to be able to provide a supply of air at a positive pressure above the ambient, for example at least 2, 4, 6, 10, or 20 cmH20 with respect to ambient.5.3.1 Seal-forming structure

[0072] In one form of the present technology, a seal-forming structure 3100 provides a target seal-forming region, and may additionally provide a cushioning function. The target seal-forming region is a region on the seal-forming structure 3100 where sealing may occur. The region where sealing actually occurs- the actual sealing surface- may change within a given treatment session, from day to day, and from patient to patient, depending on a range of factors including for example, where the patient interface was placed on the face, tension in the positioning and stabilising structure and the shape of a patient’s face.

[0073] In one form the target seal-forming region is located on an outside surface of the seal -forming structure 3100.

[0074] In certain forms of the present technology, the seal-forming structure 3100 is constructed from a biocompatible material, e.g. silicone rubber.

[0075] A seal-forming structure 3100 in accordance with the present technology may be constructed from a soft, flexible, resilient material such as silicone.

[0076] In certain forms of the present technology, a system is provided comprising more than one a seal -forming structure 3100, each being configured to correspond to a different size and / or shape range. For example, the system may comprise one form of a seal -forming structure 3100 suitable for a large sized head, but not a small sized head and another suitable for a small sized head, but not a large sized head.5.3.1.1 Sealing mechanisms

[0077] In one form, the seal-forming structure includes a sealing flange utilizing a pressure assisted sealing mechanism. In use, the sealing flange can readily respond to a system positive pressure in the interior of the plenum chamber 3200 acting on its underside to urge it into tight sealing engagement with the face. The pressure assisted mechanism may act in conjunction with elastic tension in the positioning and stabilising structure.

[0078] In one form, the seal -forming structure 3100 comprises a sealing flange and a support flange. The sealing flange comprises a relatively thin member with a thickness of less than about 1mm, for example about 0.25mm to about 0.45mm, which extends around the perimeter of the plenum chamber 3200. Support flange may be relatively thicker than the sealing flange. The support flange is disposed between the sealing flange and the marginal edge of the plenum chamber 3200, and extends at least part of the way around the perimeter. The support flange is or includes a springlike element and functions to support the sealing flange from buckling in use.

[0079] In one form, the seal -forming structure may comprise a compression sealing portion or a gasket sealing portion. In use the compression sealing portion, or the gasket sealing portion is constructed and arranged to be in compression, e.g. as a result of elastic tension in the positioning and stabilising structure.

[0080] In one form, the seal-forming structure comprises a tension portion. In use, the tension portion is held in tension, e.g. by adjacent regions of the sealing flange.

[0081] In one form, the seal -forming structure comprises a region having a tacky or adhesive surface.

[0082] In certain forms of the present technology, a seal-forming structure may comprise one or more of a pressure-assisted sealing flange, a compression sealingportion, a gasket sealing portion, a tension portion, and a portion having a tacky or adhesive surface.5.3.1.2 Nose bridge or nose ridge region

[0083] In one form, the non-invasive patient interface 3000 comprises a sealforming structure that forms a seal in use on a nose bridge region or on a nose-ridge region of the patient's face.

[0084] In one form, the seal-forming structure includes a saddle-shaped region constructed to form a seal in use on a nose bridge region or on a nose-ridge region of the patient's face.5.3.1.3 Upper lip region

[0085] In one form, the non-invasive patient interface 3000 comprises a sealforming structure that forms a seal in use on an upper lip region (that is, the lip superior) of the patient's face.

[0086] In one form, the seal-forming structure includes a saddle-shaped region constructed to form a seal in use on an upper lip region of the patient's face.5.3.1.4 Chin-region

[0087] In one form the non-invasive patient interface 3000 comprises a sealforming structure that forms a seal in use on a chin -region of the patient's face.

[0088] In one form, the seal -forming structure includes a saddle-shaped region constructed to form a seal in use on a chin-region of the patient's face.5.3.1.5 Forehead region

[0089] In one form, the seal-forming structure that forms a seal in use on a forehead region of the patient's face. In such a form, the plenum chamber may cover the eyes in use.5.3.1.6 Nasal pillows

[0090] In one form the seal -forming structure of the non-invasive patient interface 3000 comprises a pair of nasal puffs, or nasal pillows, each nasal puff or nasal pillow being constructed and arranged to form a seal with a respective naris of the nose of a patient.

[0091] Nasal pillows in accordance with an aspect of the present technology include: a frusto-cone, at least a portion of which forms a seal on an underside of the patient's nose, a stalk, a flexible region on the underside of the frusto-cone and connecting the frusto-cone to the stalk. In addition, the structure to which the nasal pillow of the present technology is connected includes a flexible region adjacent thebase of the stalk. The flexible regions can act in concert to facilitate a universal joint structure that is accommodating of relative movement both displacement and angular of the frusto-cone and the structure to which the nasal pillow is connected. For example, the frusto-cone may be axially displaced towards the structure to which the stalk is connected.5.3.2 Plenum chamber

[0092] The plenum chamber 3200 has a perimeter that is shaped to be complementary to the surface contour of the face of an average person in the region where a seal will form in use. In use, a marginal edge of the plenum chamber 3200 is positioned in close proximity to an adjacent surface of the face. Actual contact with the face is provided by the seal-forming structure 3100. The seal-forming structure 3100 may extend in use about the entire perimeter of the plenum chamber 3200. In some forms, the plenum chamber 3200 and the seal -forming structure 3100 are formed from a single homogeneous piece of material.

[0093] In certain forms of the present technology, the plenum chamber 3200 does not cover the eyes of the patient in use. In other words, the eyes are outside the pressurised volume defined by the plenum chamber. Such forms tend to be less obtrusive and / or more comfortable for the wearer, which can improve compliance with therapy.

[0094] In certain forms of the present technology, the plenum chamber 3200 is constructed from a transparent material, e.g. a transparent polycarbonate. The use of a transparent material can reduce the obtrusiveness of the patient interface, and help improve compliance with therapy. The use of a transparent material can aid a clinician to observe how the patient interface is located and functioning.

[0095] In certain forms of the present technology, the plenum chamber 3200 is constructed from a translucent material. The use of a translucent material can reduce the obtrusiveness of the patient interface, and help improve compliance with therapy.

[0096] In some forms, the plenum chamber 3200 is constructed from a rigid material such as polycarbonate. The rigid material may provide support to the sealforming structure.

[0097] In some forms, the plenum chamber 3200 is constructed from a flexible material (e.g., constructed from a soft, flexible, resilient material like silicone, textile, foam, etc.). For example, in examples then may be formed from a material which hasa Young's modulus of 0.4 GPa or lower, for example foam. In some forms of the technology the plenum chamber 3200 may be made from a material having Young's modulus of 0. IGPa or lower, for example rubber. In other forms of the technology the plenum chamber 3200 may be made from a material having a Young's modulus of 0.7MPa or less, for example between 0.7MPa and 0.3MPa. An example of such a material is silicone.5.4 RPT DEVICE

[0098] Referring now to Figs. 4A-4E, an RPT device 4000 in accordance with one aspect of the present technology comprises mechanical, pneumatic, and / or electrical components and is configured to execute one or more algorithms 4300, such as any of the methods, in whole or in part, described herein.

[0099] In many places in this document, software (e.g., algorithms, modules, services, applications and the like) and actions (e.g., functionality) performed by software are described. This is done for ease of description; it should be understood that, whenever it is described in this document that software performs any action, the action is in actuality performed by underlying hardware elements (such as a processor and a memory device) according to the instructions that comprise the software. Such functionality may, in some embodiments, be provided in the form of firmware and / or hardware implementations.

[0100] The RPT device 4000 may be configured to generate a flow of air for delivery to a patient’s airways, such as to treat one or more of the respiratory conditions described elsewhere in the present document.

[0101] In one form, the RPT device 4000 is constructed and arranged to be capable of delivering a flow of air in a range of -20 L / min to +150 L / min while maintaining a positive pressure of at least 4 cmH20, or at least 10cmH2O, or at least 20 cmH20.

[0102] The RPT device may have an external housing 4010, formed in two parts, an upper portion 4012 and a lower portion 4014. Furthermore, the external housing 4010 may include one or more panel(s) 4015. The RPT device 4000 comprises a chassis 4016 that supports one or more internal components of the RPT device 4000. The RPT device 4000 may include a handle 4018.

[0103] The pneumatic path of the RPT device 4000 may comprise one or more air path items, e.g., an inlet air filter 4112, an inlet muffler 4122, a pressure generator 4140 capable of supplying air at positive pressure (e.g., a blower 4142), an outletmuffler 4124 and one or more transducers 4270, such as pressure sensors 4272 and flow rate sensors 4274.

[0104] One or more of the air path items may be located within a removable unitary structure which will be referred to as a pneumatic block 4020. The pneumatic block 4020 may be located within the external housing 4010. In one form a pneumatic block 4020 is supported by, or formed as part of the chassis 4016.

[0105] As shown in Fig. 4C, the RPT device 4000 may have an electrical power supply 4210, one or more input devices 4220, a central controller 4230, a therapy device controller 4240, a pressure generator 4140, one or more protection circuits 4250, memory 4260, transducers 4270, data communication interface 4280 and one or more output devices 4290. Electrical components 4200 may be mounted on a single Printed Circuit Board Assembly (PCBA) 4202. In an alternative form, the RPT device 4000 may include more than one PCBA 4202.5.4.1 RPT device mechanical & pneumatic components

[0106] An RPT device may comprise one or more of the following components in an integral unit. In an alternative form, one or more of the following components may be located as respective separate units.5.4.1.1 Air filter(s)

[0107] An RPT device in accordance with one form of the present technology may include an air filter 4110, or a plurality of air filters 4110.

[0108] In one form illustrated in Fig. 4B, an inlet air filter 4112 is located at the beginning of the pneumatic path upstream of a pressure generator 4140.

[0109] In one form illustrated in Fig. 4B, an outlet air filter 4114, for example an antibacterial filter, is located between an outlet of the pneumatic block 4020 and a patient interface 3000.5.4.1.2 Muffler(s)

[0110] An RPT device in accordance with one form of the present technology may include a muffler 4120, or a plurality of mufflers 4120.

[0111] In one form of the present technology (see e.g., Fig. 4B), an inlet muffler 4122 is located in the pneumatic path upstream of a pressure generator 4140.

[0112] In one form of the present technology, an outlet muffler 4124 is located in the pneumatic path between the pressure generator 4140 and a patient interface 3000.5.4.1.3 Pressure generator

[0113] In one form of the present technology, a pressure generator 4140 for producing a flow, or a supply, of air at positive pressure is a controllable blower 4142. For example, the blower 4142 may include a brushless DC motor 4144 with one or more impellers. The impellers may be located in a volute. The blower may be capable of delivering a supply of air, for example at a rate of up to about 120 litres / minute, at a positive pressure in a range from about 4 cmH20 to about 20 cmH20, or in other forms up to about 30 cmH20 when delivering respiratory pressure therapy. The blower may be as described in any one of the following patents or patent applications the contents of which are incorporated herein by reference in their entirety: U.S.Patent No. 7,866,944; U.S. Patent No. 8,638,014; U.S. Patent No. 8,636,479; and PCT Patent Application Publication No. WO 2013 / 020167.

[0114] The pressure generator 4140 may be under the control of the therapy device controller 4240.

[0115] In other forms, a pressure generator 4140 may be a piston-driven pump, a pressure regulator connected to a high pressure source (e.g. compressed air reservoir), or a bellows.5.4.1.4 Transducer(s)

[0116] Transducers may be internal of the RPT device, or external of the RPT device. External transducers may be located for example on or form part of the air circuit, e.g., the patient interface. External transducers may be in the form of noncontact sensors such as a Doppler radar movement sensor that transmit or transfer data to the RPT device.

[0117] In one form of the present technology (see e.g., Fig. 4B), 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 generate signals representing properties of the flow of air such as a flow rate, a pressure or a temperature at that point in the pneumatic path.

[0118] In one form of the present technology, one or more transducers 4270 may be located proximate to the patient interface 3000.

[0119] In one form, a signal from a transducer 4270 may be fdtered, such as by low-pass, high-pass or band-pass filtering.5.4.1.4.1 Flow rate sensor

[0120] A flow rate sensor 4274 in accordance with the present technology may be based on a differential pressure transducer, for example, an SDP600 Series differential pressure transducer from SENSIRION.

[0121] In one form, a signal generated by the flow rate sensor 4274 and representing a flow rate is received by the central controller 4230.5.4.1.4.2 Pressure sensor

[0122] A pressure sensor 4272 in accordance with the present technology is located in fluid communication with the pneumatic path. An example of a suitable pressure sensor is a transducer from the HONEYWELL ASDX series. An alternative suitable pressure sensor is a transducer from the NPA Series from GENERAL ELECTRIC.

[0123] In one form, a signal generated by the pressure sensor 4272 and representing a pressure is received by the central controller 4230.5.4.1.4.3 Motor speed transducer

[0124] In one form of the present technology a motor speed transducer 4276 is used to determine a rotational velocity of the motor 4144 and / or the 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, for example, be a speed sensor, such as a Hall effect sensor.5.4.1.5 Anti-spill back valve

[0125] As shown in Fig. 4B, one form of the present technology, an anti-spill back valve 4160 is located between the humidifier 5000 and the pneumatic block 4020. The anti-spill back valve is constructed and arranged to reduce the risk that water will flow upstream from the humidifier 5000, for example to the motor 4144.5.4.2 RPT device electrical components5.4.2.1 Power supply

[0126] A power supply 4210 may be located internal or external of the external housing 4010 of the RPT device 4000.

[0127] In one form of the present technology, power supply 4210 provides electrical power to the RPT device 4000 only. In another form of the present technology, power supply 4210 provides electrical power to both RPT device 4000 and humidifier 5000.

[0128] In some examples, the power supply may provide electrical power to input device(s), a processor (e.g., central controller 4230), the output device 4290, and / or the pressure generator 4140. The power supply 4210 may also provide electric energy to other components of the RPT device 4000 (or the humidifier 5000, as described above) and / or other components of the RPT system (e.g., one or more sensors that are disposed on a patient interface and / or air conduit.5.4.2.2 Input devices

[0129] In one form of the present technology, an 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 via a touch screen. The buttons, switches or dials may, in one form, be physically connected to the external housing 4010, or may, in another form, be in wireless communication with a receiver that is in electrical connection to the central controller 4230.

[0130] In one form, the input device 4220 may be constructed and arranged to allow a person to select a value and / or a menu option.5.4.2.3 Central controller

[0131] In one form of the present technology, the central controller 4230 is one or a plurality of processors suitable to control an RPT device 4000. The central controller 4230 is show in Figs. 4C.

[0132] Suitable processors may include an x86 INTEL processor, a processor based on ARM® Cortex®-M processor from ARM Holdings such as an STM32 series microcontroller from ST MICROELECTRONIC. In certain alternative forms of the present technology, a 32-bit RISC CPU, such as an STR9 series microcontroller from ST MICROELECTRONICS or a 16-bit RISC CPU such as a processor from the MSP430 family of microcontrollers, manufactured by TEXAS INSTRUMENTS may also be suitable.

[0133] In one form of the present technology, the central controller 4230 is a dedicated electronic circuit.

[0134] In one form, the central controller 4230 is an application-specific integrated circuit. In another form, the central controller 4230 comprises discrete electronic components.

[0135] The central controller 4230 may be configured to receive input signal(s) from one or more transducers 4270, one or more input devices 4220, and / or the humidifier 5000.

[0136] The central controller 4230 may be configured to provide output signal(s) to one or more of an output device 4290, a pressure generator 4140, a therapy device controller 4240, a data communication interface 4280, and / or the humidifier 5000.

[0137] In some forms of the present technology, the central controller 4230 is configured to implement the one or more methodologies described herein, such as the one or more algorithms 4300 which may be implemented with processor-control instructions, expressed 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 an RPT device 4000. However, in some forms of the present technology, some methodologies may be performed by a remotely located device. For example, the remotely located device may determine control settings for a ventilator or detect respiratory related events by analysis of stored data such as from any of the sensors described herein.5.4.2.4 Clock

[0138] The RPT device 4000 may include a clock 4232 that is connected to the central controller 4230.5.4.2.5 Therapy device controller

[0139] In one form of the present technology, therapy device controller 4240 is a therapy control module 4330 that forms part of the algorithms 4300 executed by the central controller 4230.

[0140] In one form of the present technology, therapy device controller 4240 is a dedicated motor control integrated circuit. For example, in one form a MC33035 brushless DC motor controller, manufactured by ONSEMI is used.5.4.2.6 Protection circuits

[0141] The one or more protection circuits 4250 in accordance with the present technology may comprise an electrical protection circuit, a temperature and / or pressure safety circuit.5.4.2.7 Memory

[0142] In accordance with one form of the present technology the RPT device 4000 includes memory 4260, e.g., non-volatile memory. In some forms, memory4260 may include battery powered static RAM. In some forms, memory 4260 may include volatile RAM.

[0143] Memory 4260 may be located on the PCBA 4202. Memory 4260 may be in the form of EEPROM, or NAND flash.

[0144] Additionally, or alternatively, RPT device 4000 includes a removable form of memory 4260, for example a memory card made in accordance with the Secure Digital (SD) standard.

[0145] In one form of the present technology, the memory 4260 acts as a non- transitory computer readable storage medium on which is stored computer program instructions expressing the one or more methodologies described herein, such as the one or more algorithms 4300, software, etc..5.4.2.8 Data communication systems

[0146] In one form of the present technology, a data communication interface4280 is provided, and is connected to the central controller 4230 (see e.g., Fig. 4C). Data communication interface 4280 may be connectable to a remote external communication network 4282 and / or a local external communication network 4284. The remote external communication network 4282 may be connectable to a remote external device 4286. The local external communication network 4284 may be connectable to a local external device 4288.

[0147] In one form, data communication interface 4280 is part of the central controller 4230. In another form, data communication interface 4280 is separate from the central controller 4230, and may comprise an integrated circuit or a processor.

[0148] In one form, remote external communication network 4282 is the Internet. The data communication interface 4280 may use wired communication (e.g. via Ethernet, or optical fibre) or a wireless protocol (e.g. CDMA, GSM, LTE) to connect to the Internet.

[0149] In one form, local external communication network 4284 utilises one or more communication standards, such as Bluetooth, or a consumer infrared protocol.

[0150] In one form, remote external device 4286 is one or more computers, for example a cluster of networked computers. In one form, remote external device 4286 may be virtual computers, rather than physical computers. In either case, such a remote external device 4286 may be accessible to an appropriately authorised person such as a clinician.

[0151] The local external device 4288 may be a personal computer, mobile phone, tablet or remote control.5.4.2.9 Output devices including optional display, alarms

[0152] An output device 4290 in accordance with the present technology may take the form of one or more of a visual, audio and haptic unit. A visual display may be a Liquid Crystal Display (LCD) or Light Emitting Diode (LED) display.5.4.2.9.1 Display driver

[0153] A display driver 4292 receives as an input the characters, symbols, or images intended for display on the display 4294, and converts them to commands that cause the display 4294 to display those characters, symbols, or images.5.4.2.9.2 Display

[0154] A 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 figure “0”, to eight logical signals indicating whether the eight respective segments are to be activated to display a particular character or symbol.5.4.3 RPT device algorithms

[0155] As mentioned above, in some forms of the present technology, the central controller 4230 may be configured to implement one or more algorithms 4300 expressed as computer programs stored in a non-transitory computer readable storage medium, such as memory 4260. The algorithms 4300 are generally grouped into groups referred to as modules.

[0156] In other forms of the present technology, some portion or all of the algorithms 4300 may be implemented by a controller of an external device such as the local external device 4288 or the remote external device 4286. In such forms, data representing the input signals and / or intermediate algorithm outputs necessary for the portion of the algorithms 4300 to be executed at the external device may be communicated to the external device via the local external communication network 4284 or the remote external communication network 4282. In such forms, the portion of the algorithms 4300 to be executed at the external device may be expressed as computer programs, such as with processor control instructions to be executed by one or more processor(s), stored in a non-transitory computer readable storage mediumaccessible to the controller of the external device. Such programs configure the controller of the external device to execute the portion of the algorithms 4300.

[0157] In such forms, the therapy parameters generated by the external device via the therapy engine module 4320 (if such forms part of the portion of the algorithms 4300 executed by the external device) may be communicated to the central controller 4230 to be passed to the therapy control module 4330.5.4.3.1 Pre-processing module

[0158] A pre-processing module 4310 in accordance with one form of the present technology receives as an input a signal from a transducer 4270, for example a flow rate sensor 4274 or pressure sensor 4272, and performs one or more process steps to calculate one or more output values that will be used as an input to another module, for example a therapy engine module 4320.

[0159] In one form of the present technology, the output values include the interface pressure Pm, the vent flow rate Qy, the respiratory flow rate Qr, and the leak flow rate QI.

[0160] In various forms of the present technology, the pre-processing module 4310 comprises one or more of the following algorithms: interface pressure estimation 4312, vent flow rate estimation 4314, leak flow rate estimation 4316, and respiratory flow rate estimation 4318.5.4.3.1.1 Interface pressure estimation

[0161] In one form of the present technology, an interface pressure estimation algorithm 4312 receives as inputs a signal from the pressure sensor 4272 indicative of the pressure in the pneumatic path proximal to an outlet of the pneumatic block (the device pressure Pd) and a signal from the flow rate sensor 4274 representative of the flow rate of the airflow leaving the RPT device 4000 (the device flow rate Qd). The device flow rate Qd, absent any supplementary gas 4180, may be used as the total flow rate Qt. The interface pressure algorithm 4312 estimates the pressure drop AP through the air circuit 4170. The dependence of the pressure drop AP on the total flow rate Qt may be modelled for the particular air circuit 4170 by a pressure drop characteristic AP(Q). The interface pressure estimation algorithm, 4312 then provides as an output an estimated pressure, Pm, in the patient interface 3000. The pressure, Pm, in the patient interface 3000 may be estimated as the device pressure Pd minus the air circuit pressure drop AP.5.4.3.1.2 Vent flow rate estimation

[0162] In one form of the present technology, a vent flow rate estimation algorithm 4314 receives as an input an estimated pressure, Pm, in the patient interface 3000 from the interface pressure estimation algorithm 4312 and estimates a vent flow rate of air, Qv, from a vent 3400 in a patient interface 3000. The dependence of the vent flow rate Qv on the interface pressure Pm for the particular vent 3400 in use may be modelled by a vent characteristic Qv(Pm).5.4.3.1.3 Leak flow rate estimation

[0163] In one form of the present technology, a leak flow rate estimation algorithm 4316 receives as an input a total flow rate, Qt, and a vent flow rate Qv, and provides as an output an estimate of the leak flow rate QI. In one form, the leak flow rate estimation algorithm estimates the leak flow rate QI by calculating an average of the difference between total flow rate Qt and vent flow rate Qv over a period sufficiently long to include several breathing cycles, e.g. about 10 seconds.

[0164] In one form, the leak flow rate estimation algorithm 4316 receives as an input a total flow rate Qt, a vent flow rate Qv, and an estimated pressure, Pm, in the patient interface 3000, and provides as an output a leak flow rate QI, by calculating a leak conductance, and determining a leak flow rate QI to be a function of leak conductance and pressure, Pm. Leak conductance is calculated as the quotient of low pass filtered non-vent flow rate equal to the difference between total flow rate Qt and vent flow rate Qv, and low pass filtered square root of pressure Pm, where the low pass filter time constant has a value sufficiently long to include several breathing cycles, e.g. about 10 seconds. The leak flow rate QI may be estimated as the product of leak conductance and a function of pressure, Pm.5.4.3.1.4 Respiratory flow rate estimation

[0165] In one form of the present technology, a respiratory flow rate estimation algorithm 4318 receives as an input a total flow rate, Qt, a vent flow rate, Qv, and a leak flow rate, QI, and estimates a respiratory flow rate of air, Qr, to the patient, by subtracting the vent flow rate Qv and the leak flow rate QI from the total flow rate Qt.5.4.3.2 Therapy Engine Module

[0166] In one form of the present technology, a therapy engine module 4320 receives as inputs one or more of a pressure, Pm, in a patient interface 3000, and a respiratory flow rate of air to a patient, Qr, and provides as an output one or more therapy parameters.

[0167] In one form of the present technology, a therapy parameter is a treatment pressure Pt.

[0168] In one form of the present technology, therapy parameters are one or more of an amplitude of a pressure variation, a base pressure, and a target ventilation.

[0169] In various forms, the therapy engine module 4320 comprises 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, snore determination 4326, airway patency determination 4327, target ventilation determination 4328, and therapy parameter determination 4329.5.4.3.2.1 Phase determination

[0170] In one form of the present technology, the RPT device 4000 does not determine phase.

[0171] In one form of the present technology, a phase determination algorithm 4321 receives as an input a signal indicative of respiratory flow rate, Qr, and provides as an output a phase of a current breathing cycle of a patient 1000.

[0172] In some forms, known as discrete phase determination, the phase output > is a discrete variable. One implementation of discrete phase determination provides a bi-valued phase output <b with values of either inhalation or exhalation, for example represented as values of 0 and 0.5 revolutions respectively, upon detecting the start of spontaneous inhalation and exhalation respectively. RPT devices 4000 that “trigger” and “cycle” effectively perform discrete phase determination, since the trigger and cycle points are the instants at which the phase changes from exhalation to inhalation and from inhalation to exhalation, respectively. In one implementation of bi-valued phase determination, the phase output <4> is determined to have a discrete value of 0 (thereby “triggering” the RPT device 4000) when the respiratory flow rate Qr has a value that exceeds a positive threshold, and a discrete value of 0.5 revolutions (thereby “cycling” the RPT device 4000) when a respiratory flow rate Qr has a value that is more negative than a negative threshold. The inhalation time Ti and the exhalation time Te may be estimated as typical values over many respiratory cycles of the time spent with phase <4> equal to 0 (indicating inspiration) and 0.5 (indicating expiration) respectively.

[0173] Another implementation of discrete phase determination provides a trivalued phase output <t> with a value of one of inhalation, mid-inspiratory pause, and exhalation.

[0174] In other forms, known as continuous phase determination, the phase output is a continuous variable, for example varying from 0 to 1 revolutions, or 0 to 2 radians. RPT devices 4000 that perform continuous phase determination may trigger and cycle when the continuous phase reaches 0 and 0.5 revolutions, respectively. In one implementation of continuous phase determination, a continuous value of phase <b is determined using a fuzzy logic analysis of the respiratory flow rate Qr. A continuous value of phase determined in this implementation is often referred to as “fuzzy phase”. In one implementation of a fuzzy phase determination algorithm 4321, the following rules are applied to the respiratory flow rate Qr.1. If Qr is zero and increasing fast then is 0 revolutions.2. If Qr is large positive and steady then <b is 0.25 revolutions.3. If Qr is zero and falling fast, then <b is 0.5 revolutions.4. If Qr is large negative and steady then <b is 0.75 revolutions.5. If Qr is zero and steady and the 5 -second low-pass filtered absolute value of Qr is large then <b is 0.9 revolutions.6. If Qr is positive and the phase is expiratory, then is 0 revolutions.7. If Qr is negative and the phase is inspiratory, then <b is 0.5 revolutions.8. If the 5 -second low-pass filtered absolute value of Qr is large, <b is increasing at a steady rate equal to the patient’s breathing rate, low -pass filtered with a time constant of 20 seconds.

[0175] The output of each rule may be represented as a vector whose phase is the result of the rule and whose magnitude is the fuzzy extent to which the rule is true. The fuzzy extent to which the respiratory flow rate is “large”, “steady”, etc. is determined with suitable 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 may be equally weighted, or differently weighted.

[0176] In another implementation of continuous phase determination, the phase <b is first discretely estimated from the respiratory flow rate Qr as described above, as are the inhalation time Ti and the exhalation time Te. The continuous phase <b at any instant may be determined as the half the proportion of the inhalation time Ti that haselapsed since the previous trigger instant, or 0.5 revolutions plus half the proportion of the exhalation time Te that has elapsed since the previous cycle instant (whichever instant was more recent).5.4.3.2.2 Waveform determination

[0177] In one form of the present technology, the therapy parameter determination algorithm 4329 provides an approximately constant treatment pressure throughout a respiratory cycle of a patient.

[0178] In other forms of the present technology, the therapy control module 4330 controls the pressure generator 4140 to provide a treatment pressure t that varies as a function of phase of a respiratory cycle of a patient according to a waveform template 1 ( ).

[0179] In one form of the present technology, a waveform determination algorithm 4322 provides a waveform template 14( ) with values in the range [0, 1] on the domain of phase values provided by the phase determination algorithm 4321 to be used by the therapy parameter determination algorithm 4329.

[0180] In one form, suitable for either discrete or continuously-valued phase, the waveform template 44 ( ) is a square-wave template, having a value of 1 for values of phase up to and including 0.5 revolutions, and a value of 0 for values of phase above 0.5 revolutions. In one form, suitable for continuously-valued phase, the waveform template 44() comprises two smoothly curved portions, namely a smoothly curved (e.g. raised cosine) rise from 0 to 1 for values of phase up to 0.5 revolutions, and a smoothly curved (e.g. exponential) decay from 1 to 0 for values of phase above 0.5 revolutions. In one form, suitable for continuously- valued phase, the waveform template 44() is based on a square wave, but with a smooth rise from 0 to 1 for values of phase up to a “rise time” that is less than 0.5 revolutions, and a smooth fall from 1 to 0 for values of phase within a “fall time” after 0.5 revolutions, with a “fall time” that is less than 0.5 revolutions.

[0181] In some forms of the pre sent technology, the waveform determination algorithm 4322 selects a waveform template 44 ( ) from a library of waveform templates, dependent on a setting of the RPT device. Each waveform template 14( ) in the library may be provided as a lookup table of values 14 against phase values O. In other forms, the waveform determination algorithm 4322 computes a waveform template 44 (O) “on the fly” using a predetermined functional form, possiblyparametrised by one or more parameters (e.g. time constant of an exponentially curved portion). The parameters of the functional form may be predetermined or dependent on a current state of the patient 1000.

[0182] In some forms of the present technology, suitable for discrete bi-valued phase of either inhalation ( = 0 revolutions) or exhalation ( = 0.5 revolutions), the waveform determination algorithm 4322 computes a waveform template fl “on the fly” as a function of both discrete phase and time t measured since the most recent trigger instant. In one such form, the waveform determination algorithm 4322 computes the waveform template 11( , t) in two portions (inspiratory and expiratory) as follows: o = o0 = 0.5

[0183] where □,( / ) and Hc( / ) are inspiratory and expiratory portions of the waveform template 11(0, t). In one such form, the inspiratory portion □,( / ) of the waveform template is a smooth rise from 0 to 1 parametrised by a rise time, and the expiratory portion ne( / ) of the waveform template is a smooth fall from 1 to 0 parametrised by a fall time.5.4.3.2.3 Ventilation determination

[0184] In one form of the present technology, a ventilation determination algorithm 4323 receives an input a respiratory flow rate Qr, and determines a measure indicative of current patient ventilation, Vent.

[0185] In some implementations, the ventilation determination algorithm 4323 determines a measure of ventilation Vent that is an estimate of actual patient ventilation. One such implementation is to take half the absolute value of respiratory flow rate, Qr, optionally filtered by low-pass filter such as a second order Bessel low- pass filter with a comer frequency of 0. 11 Hz.

[0186] In other implementations, the ventilation determination algorithm 4323 determines a measure of ventilation Vent that is broadly proportional to actual patient ventilation. One such implementation estimates peak respiratory flow rate Qpeak over the inspiratory portion of the cycle. This and many other procedures involving sampling the respiratory flow rate Qr produce measures which are broadly proportional to ventilation, provided the flow rate waveform shape does not vary very much (here, the shape of two breaths is taken to be similar when the flow ratewaveforms of the breaths normalised in time and amplitude are similar). Some simple examples include the median positive respiratory flow rate, the median of the absolute value of respiratory flow rate, and the standard deviation of flow rate. Arbitrary linear combinations of arbitrary order statistics of the absolute value of respiratory flow rate using positive coefficients, and even some using both positive and negative coefficients, are approximately proportional to ventilation. Another example is the mean of the respiratory flow rate in the middle K proportion (by time) of the inspiratory portion, where 0 < K < 1. There is an arbitrarily large number of measures that are exactly proportional to ventilation if the flow rate shape is constant.5.4.3.2.4 Determin ation of Inspiratory Flow Limitation

[0187] In one form of the present technology, the central controller 4230 executes an inspiratory flow limitation determination algorithm 4324 for the determination of the extent of inspiratory flow limitation.

[0188] In one form, the inspiratory flow limitation determination algorithm 4324 receives as an input a respiratory flow rate signal Qr and provides as an output a metric of the extent to which the inspiratory portion of the breath exhibits inspiratory flow limitation.

[0189] In one form of the present technology, the inspiratory portion of each breath is identified by a zero-crossing detector. A number of evenly spaced points (for example, sixty-five), representing points in time, are interpolated by an interpolator along the inspiratory flow rate-time curve for each breath. The curve described by the points is then scaled by a scalar to have unity length (duration / period) and unity area to remove the effects of changing breathing rate and depth. The scaled breaths are then compared in a comparator with a pre-stored template representing a normal unobstructed breath, similar to the inspiratory portion of the breath shown in Fig. 6A. Breaths deviating by more than a specified threshold (typically 1 scaled unit) at any time during the inspiration from this template, such as those due to coughs, sighs, swallows and hiccups, as determined by a test element, are rejected. For non-rejected data, a moving average of the first such scaled point is calculated by the central controller 4230 for the preceding several inspiratory events. This is repeated over the same inspiratory events for the second such point, and so on. Thus, for example, sixty-five scaled data points are generated by the central controller 4230, and represent a moving average of the preceding several inspiratory events, e.g., three events. The moving average of continuously updated values of the (e.g., sixty-five)points are hereinafter called the "scaled flow rate ", designated as Qs(t). Alternatively, a single inspiratory event can be utilised rather than a moving average.

[0190] From the scaled flow rate, two shape factors relating to the determination of partial obstruction may be calculated.

[0191] Shape factor 1 is the ratio of the mean of the middle (e.g. thirty-two) scaled flow rate points to the mean overall (e.g. sixty-five) scaled flow rate points. Where this ratio is in excess of unity, the breath will be taken to be normal. Where the ratio is unity or less, the breath will be taken to be obstructed. A ratio of about 1. 17 is taken as a threshold between partially obstructed and unobstructed breathing, and equates to a degree of obstruction that would permit maintenance of adequate oxygenation in a typical patient.

[0192] Shape factor 2 is calculated as the RMS deviation from unit scaled flow rate, taken over the middle (e.g. thirty-two) points. An RMS deviation of about 0.2 units is taken to be normal. An RMS deviation of zero is taken to be a totally flowlimited breath. The closer the RMS deviation to zero, the breath will be taken to be more flow limited.

[0193] Shape factors 1 and 2 may be used as alternatives, or in combination. In other forms of the present technology, the number of sampled points, breaths and middle points may differ from those described above. Furthermore, the threshold values can be other than those described.5.4.3.2.5 Determination of apneas and hypopneas

[0194] In one form of the present technology, the central controller 4230 executes an apnea / hypopnea determination algorithm 4325 for the determination of the presence of apneas and / or hypopneas.

[0195] In one form, the apnea / hypopnea determination algorithm 4325 receives as an input a respiratory flow rate signal Qr and provides as an output a flag that indicates that an apnea or a hypopnea has been detected.

[0196] In one form, an apnea will be said to have been detected when a function of respiratory flow rate Qr falls below a flow rate threshold for a predetermined period of time. The function may determine a peak flow rate, a relatively short-term mean flow rate, or a flow rate intermediate of relatively short-term mean and peak flow rate, for example an RMS flow rate. The flow rate threshold may be a relatively long-term measure of flow rate.

[0197] In one form, a hypopnea will be said to have been detected when a function of respiratory flow rate Qr falls below a second flow rate threshold for a predetermined period of time. The function may determine a peak flow, a relatively short-term mean flow rate, or a flow rate intermediate of relatively short-term mean and peak flow rate, for example an RMS flow rate. The second flow rate threshold may be a relatively long-term measure of flow rate. The second flow rate threshold is greater than the flow rate threshold used to detect apneas.5.4.3.2.6 Determination of snore

[0198] In one form of the present technology, the central controller 4230 executes one or more snore determination algorithms 4326 for the determination of the extent of snore.

[0199] In one form, the snore determination algorithm 4326 receives as an input a respiratory flow rate signal Qr and provides as an output a metric of the extent to which snoring is present.

[0200] The snore determination algorithm 4326 may comprise the step of determining the intensity of the flow rate signal in the range of 30-300 Hz. Further, the snore determination algorithm 4326 may comprise a step of filtering the respiratory flow rate signal Qr to reduce background noise, e.g., the sound of airflow in the system from the blower.5.4.3.2. 7 Determination of airway patency

[0201] In one form of the present technology, the central controller 4230 executes one or more airway patency determination algorithms 4327 for the determination of the extent of airway patency.

[0202] In one form, the airway patency determination algorithm 4327 receives as an input a respiratory flow rate signal Qr, and determines the power of the signal in the frequency range of about 0.75 Hz and about 3 Hz. The presence of a peak in this frequency range is taken to indicate an open airway. The absence of a peak is taken to be an indication of a closed airway.

[0203] In one form, the frequency range within which the peak is sought is the frequency of a small forced oscillation in the treatment pressure Pt. In one implementation, the forced oscillation is of frequency 2 Hz with amplitude about 1 cmHiO.

[0204] In one form, airway patency determination algorithm 4327 receives as an input a respiratory flow rate signal Qr, and determines the presence or absence of acardiogenic signal. The absence of a cardiogenic signal is taken to be an indication of a closed airway.5.4.3.2.8 Determin ation of target ventilation

[0205] In one form of the present technology, the central controller 4230 takes as input the measure of current ventilation, Vent, and executes one or more target ventilation determination algorithms 4328 for the determination of a target value Vtgt for the measure of ventilation.

[0206] In some forms of the present technology, there is no target ventilation determination algorithm 4328, and the target value Vtgt is predetermined, for example by hard-coding during configuration of the RPT device 4000 or by manual entry through the input device 4220.

[0207] In other forms of the present technology, such as adaptive servoventilation (ASV), the target ventilation determination algorithm 4328 computes a target value Vtgt from a value Vtyp indicative of the typical recent ventilation of the patient.

[0208] In some forms of adaptive servo-ventilation, the target ventilation Vtgt is computed as a high proportion of, but less than, the typical recent ventilation Vtyp. The high proportion in such forms may be in the range (80%, 100%), or (85%, 95%), or (87%, 92%).

[0209] In other forms of adaptive servo-ventilation, the target ventilation Vtgt is computed as a slightly greater than unity multiple of the typical recent ventilation J7y .

[0210] The typical recent ventilation Vtyp is the value around which the distribution of the measure of current ventilation Vent over multiple time instants over some predetermined timescale tends to cluster, that is, a measure of the central tendency of the measure of current ventilation over recent history. In one implementation of the target ventilation determination algorithm 4328, the recent history is of the order of several minutes, but in any case should be longer than the timescale of Cheyne-Stokes waxing and waning cycles. The target ventilation determination algorithm 4328 may use any of the variety of well-known measures of central tendency to determine the typical recent ventilation Vtyp from the measure of current ventilation, Vent. One such measure is the output of a low-pass fdter on the measure of current ventilation Vent, with time constant equal to one hundred seconds.5.4.3.2.9 Determination of therapy parameters

[0211] In some forms of the present technology, the central controller 4230 executes one or more therapy parameter determination algorithms 4329 for the determination of one or more therapy parameters using the values returned by one or more of the other algorithms in the therapy engine module 4320.

[0212] In one form of the present technology, the therapy parameter is an instantaneous treatment pressure Pt. In one implementation of this form, the therapy parameter determination algorithm 4329 determines the treatment pressure Pt using the equation

[0213] where:• A is the amplitude,• H( . t) is the waveform template value (in the range 0 to 1) at the current value <4> of phase and t of time, and• Po is a base pressure.

[0214] If the waveform determination algorithm 4322 provides the waveform template II(<b, t) as a lookup table of values II indexed by phase <b, the therapy parameter determination algorithm 4329 applies equation (1) by locating the nearest lookup table entry to the current value <4> of phase returned by the phase determination algorithm 4321, or by interpolation between the two entries straddling the current value <4> of phase.

[0215] The values of the amplitude A and the base pressure Po may be set by the therapy parameter determination algorithm 4329 depending on the chosen respiratory pressure therapy mode in the manner described below.5.4.3.3 Therapy Control module

[0216] The therapy control module 4330 in accordance with one aspect of the present technology receives as inputs the therapy parameters from the therapy parameter determination algorithm 4329 of the therapy engine module 4320, and controls the pressure generator 4140 to deliver a flow of air in accordance with the therapy parameters.

[0217] In one form of the present technology, the therapy parameter is a treatment pressure Pt, and the therapy control module 4330 controls the pressuregenerator 4140 to deliver a flow of air whose interface pressure Pm at the patient interface 3000 is equal to the treatment pressure Pt.5.4.3.4 Detection of fault conditions

[0218] In one form of the present technology, the central controller 4230 executes one or more methods 4340 for the detection of fault conditions. The fault conditions detected by the one or more methods 4340 may include at least one of the following:• Power failure (no power, or insufficient power)• Transducer fault detection• Failure to detect the presence of a component• Operating parameters outside recommended ranges (e.g. pressure, flow rate, temperature, PaO2)• Failure of a test alarm to generate a detectable alarm signal.

[0219] Upon detection of the fault condition, the corresponding algorithm 4340 signals the presence of the fault by one or more of the following:• Initiation of an audible, visual & / or kinetic (e.g. vibrating) alarm• Sending a message to an external device• Logging of the incident5.5 AIR CIRCUIT

[0220] An air circuit 4170 in accordance with an aspect of the present technology is a conduit or a tube constructed and arranged to allow, in use, a flow of air to travel between two components such as RPT device 4000 and the patient interface 3000.

[0221] In particular, the air circuit 4170 may be in fluid connection with the outlet of the pneumatic block 4020 and the patient interface. The air circuit may be referred to as an air delivery tube. In some cases, there may be separate limbs of the circuit for inhalation and exhalation. In other cases, a single limb is used.

[0222] In some forms, the air circuit 4170 may comprise one or more heating elements configured to heat air in the air circuit, for example to maintain or raise the temperature of the air. The heating element may be in a form of a heated wire circuit, and may comprise one or more transducers, such as temperature sensors. In one form, the heated wire circuit may be helically wound around the axis of the air circuit 4170. The heating element may be in communication with a controller such as a central controller 4230.5.6 HUMIDIFIER5.6.1 Humidifier overview

[0223] In one form of the present technology there is provided a humidifier 5000 (e.g. as shown in Fig. 5A) to change the absolute humidity of air or gas for delivery to a patient relative to ambient air. Typically, the humidifier 5000 is used to increase the absolute humidity and increase the temperature of the flow of air (relative to ambient air) before delivery to the patient’s airways.

[0224] The humidifier 5000 may comprise a humidifier reservoir 5110, a humidifier inlet 5002 to receive a flow of air, and a humidifier outlet 5004 to deliver a humidified flow of air. In some forms, as shown in Fig. 5A and Fig. 5B, an inlet and an outlet of the humidifier reservoir 5110 may be the humidifier inlet 5002 and the humidifier outlet 5004 respectively. The humidifier 5000 may further comprise a humidifier base 5006, which may be adapted to receive the humidifier reservoir 5110 and comprise a heating element 5240.5.7 BREATHING WAVEFORMS

[0225] Fig. 6 shows a model typical breath waveform of a person while sleeping. The horizontal axis is time, and the vertical axis is respiratory flow rate. While the parameter values may vary, a typical breath may have the following approximate values: tidal volume Vt 0.5L, inhalation time Ti 1.6s, peak inspiratory flow rate Qpeak 0.4 L / s, exhalation time Te 2.4s, peak expiratory flow rate Qpeak -0.5 L / s. The total duration of the breath, Ttot, is about 4s. The person typically breathes at a rate of about 15 breaths per minute (BPM), with Ventilation Vent about 7.5 L / min. A typical duty cycle, the ratio of Ti to Ttot, is about 40%. In some examples, the breath wave form shown in Fig. 6 may correspond to a respiratory flow signal.5.8 RESPIRATORY THERAPY MODES

[0226] Various respiratory therapy modes may be implemented by the disclosed respiratory therapy system.5.8.1 CPAP therapy

[0227] In some implementations of respiratory pressure therapy, the central controller 4230 sets the treatment pressure Pt according to the treatment pressure equation (1) as part of the therapy parameter determination algorithm 4329. In one such implementation, the amplitude A is identically zero, so the treatment pressure Pt (which represents a target value to be achieved by the interface pressure Pm at thecurrent instant of time) is identically equal to the base pressure Po throughout the respiratory cycle. Such implementations are generally grouped under the heading of CPAP therapy. In such implementations, there is no need for the therapy engine module 4320 to determine phase <b or the waveform template Flf ).

[0228] In CPAP therapy, the base pressure Po may be a constant value that is hard-coded or manually entered to the RPT device 4000. Alternatively, the central controller 4230 may repeatedly compute the base pressure Po as a function of indices or measures of sleep disordered breathing returned by the respective algorithms in the therapy engine module 4320, such as one or more of flow limitation, apnea, hypopnea, patency, and snore. This alternative is sometimes referred to as APAP therapy.

[0229] Fig. 4E is a flow chart illustrating a method 4500 carried out by the central controller 4230 to continuously compute the base pressure Po as part of an APAP therapy implementation of the therapy parameter determination algorithm 4329, when the pressure support^ is identically zero.

[0230] The method 4500 starts at step 4520, at which the central controller 4230 compares the measure of the presence of apnea / hypopnea with a first threshold, and determines whether the measure of the presence of apnea / hypopnea has exceeded the first threshold for a predetermined period of time, indicating an apnea / hypopnea is occurring. If so, the method 4500 proceeds to step 4540; otherwise, the method 4500 proceeds to step 4530. At step 4540, the central controller 4230 compares the measure of airway patency with a second threshold. If the measure of airway patency exceeds the second threshold, indicating the airway is patent, the detected apnea / hypopnea is deemed central, and the method 4500 proceeds to step 4560; otherwise, the apnea / hypopnea is deemed obstructive, and the method 4500 proceeds to step 4550.

[0231] At step 4530, the central controller 4230 compares the measure of flow limitation with a third threshold. If the measure of flow limitation exceeds the third threshold, indicating inspiratory flow is limited, the method 4500 proceeds to step 4550; otherwise, the method 4500 proceeds to step 4560.

[0232] At step 4550, the central controller 4230 increases the base pressure Po by a predetermined pressure increment AP, provided the resulting treatment pressure Pt would not exceed a maximum treatment pressure Pmax. In one implementation, thepredetermined pressure increment AP and maximum treatment pressure Pmax are 1 cmH20 and 25 cmH20 respectively. In other implementations, the pressure increment AP can be as low as 0.1 cmH20 and as high as 3 cmH20, or as low as 0.5 cmH2O and as high as 2 cmH2O. In other implementations, the maximum treatment pressure Pmax can be as low as 15 cmH20 and as high as 35 cmH20, or as low as 20 cmH2O and as high as 30 cmH2O. The method 4500 then returns to step 4520.

[0233] At step 4560, the central controller 4230 decreases the base pressure P by a decrement, provided the decreased base pressure Po would not fall below a minimum treatment pressure Pmin. The method 4500 then returns to step 4520. In one implementation, the decrement is proportional to the value of Po-Pmin, so that the decrease in Po to the minimum treatment pressure Pmin in the absence of any detected events is exponential. In one implementation, the constant of proportionality is set such that the time constant rof the exponential decrease of P is 60 minutes, and the minimum treatment pressure Pmin is 4 cmH20. In other implementations, the time constant T could be as low as 1 minute and as high as 300 minutes, or as low as 5 minutes and as high as 180 minutes. In other implementations, the minimum treatment pressure Pmin can be as low as 0 cmH20 and as high as 8 cmH20, or as low as 2 cmH20 and as high as 6 cmH20. Alternatively, the decrement in Po could be predetermined, so the decrease in Po to the minimum treatment pressure Pmin in the absence of any detected events is linear.5.9 HEART RATE SYSTEMS

[0234] Figure 7 illustrates an example heart rate system 7001. The heart rate system 7001 includes a respiratory therapy system 7000. The respiratory therapy system 7000 may share any or all of the features of the respiratory therapy system discussed in connection with Figure 1. The example respiratory therapy system 7000 includes a RPT device 7002 (which is an example of RPT device 4000), air circuit 7004 (which is an example of air circuit 4170), patient interface 7008 (which is an example of patient interface 3000) that, in use, is configured to provide respiratory therapy to a patient 7010. The heart rate system 7001 also may include one or more computing devices 7030. Computing device 7030 may include, for example a desktop or laptop computer, a mobile device that may be a tablet or phone, or may include a server computer system or a cloud-computing system. Computing device(s) 7030 may include remote external device 4286 and / or local external device 4288.

[0235] In some forms, RPT device 7002 is an example of, or may be, RPT device 4000. In some forms, tube 7004 is an example of, or may be, air circuit 4170. In some forms, patient interface 7008 is an example of, or may be, patient interface 3000.

[0236] Tube 7004 includes an inertial measurement unit (IMU) 7006. As discussed elsewhere herein, IMU 7006 may be disposed within tube (e.g., embedded within the material that is used for the tube), on an inner surface of the tube 7004 (e.g., the surface of the inner part of the tube), on an outer surface of the tube 7004, or some combination thereof. The included IMU may be disposed with a cuff that is part of tube 7004.

[0237] IMU 7006 may include one or more sensors including any or all of an acceleration sensor or accelerometer (e.g., a 3-axis acceleration sensor), a gyro sensor (e.g., a 3-axis gyroscope), and a compass (e.g., digital compass or a magnetometer).In some examples, the acceleration sensor and / or a gyro sensor may sense only one or two degrees (e.g., 1-axis or 2-axis) of movement. In some examples, the IMU 7006 includes an acceleration sensor and a gyro sensor, but not a compass. In other examples, the IMU 7006 includes just an acceleration sensor or just a gyro sensor. In other examples, a compass is combined with a gyro sensor or an acceleration sensor. Illustrative examples of an IMU include MEMS motion sensors that may include the MPU-9150, MPU-9250, ICM-20948, and other types of sensors.

[0238] In some examples, the IMU 7006 may include (or be coupled to, via a circuit board) one or more hardware processors that process the data from the one or more sensors of the IMU. In other words, a resulting sensor output from the IMU may be a digitally processed signal that is based on output from: 1) an accelerometer;2) a gyro sensor; 3) a compass, 4) or some combination thereof. The output from the IMU may thus be raw sensor data from the one or more sensors or may be a signal / data that is based on such raw sensor data. Input to the processes discussed in connection with Figure 9A and 9B may be: 1) the data output from the one or more sensors, 2) processed data generated based on such data, and / or 3) some combination thereof. In some examples, the IMU may include processing for performing one or more of the elements discussed in Figures 9A or 9B.

[0239] In some examples, the IMU 7006 may be electrically connected to the RPT device 7002 via one or more wires 7005. The wires 7005 may provide power for the IMU 7006 and / or may provide a medium for transfer of data from the RPT device7002 to the IMU 7006 and / or patient interface 7008. In some examples, the IMU 7006 may be powered via a battery and may include (or be coupled to) a wireless transmitter configured to wirelessly communicate data to another computing system (e.g., for use in connection with, for example) the various techniques described herein).

[0240] In some examples, IMU 7006 is disposed on a patient-movable structure 7020. In some examples, the patient-movable structure 7020 is, or includes, tube 7004 on the patient side of the tube 7004. In other words, the IMU 7006 may be disposed on a side / end (e.g., the proximal end) of the tube 7004 that is closer to the patient 7010 (and patient interface 7008) than the side to which the tube 7004 is configured to couple to the RPT device 7002 (e.g., the distal end of the tube). In some examples, the tube may include multiple components (e.g., multiple separate removeable attachable structural portions). In some examples, the IMU may be disposed on a component of the tube 7004 that is structurally connected to the patient interface such that the component may generally move as the patient move based on movement by the patient.

[0241] In some examples, the patient-movable structure 7020 may include any of the tube 7004 (e.g., a portion of the tube that is configured to couple to the patient interface 7008), patient interface 7008, the patient 7010, and / or other structure associated with the patient interface 7008 or the patient 7010. In some examples, the patient-movable structure 7020 includes structure that is linked to or associated with a patient 7010 while they are sleeping and can be used to obtain (via the IMU) movements (e.g., micromovements) that may be associated with, for example, ballistocardiography (BSG) techniques and the like. In some examples, patient side structure 7020 may include separate sensors (e.g., an IMU) that may be worn by the patient (e.g., as a chest strap, a ring, a watch, etc.). In some examples, the IMU 7006 may be disposed on or in headgear of the patient interface, for example, associated with a connection port, forehead support, or nasal bridge region of a patient interface (e.g., as shown in Figure 3). In some examples, and as discussed in further detail in connection with Figures 8A and 8B, an IMU 7006 may be disposed in a structure (e.g., a cuff) that is used to couple the air circuit 7004 to the patient interface 7008.

[0242] Other locations for placement of sensors for determining heart rate may be used in accordance with various example embodiment. As an illustrative example, a sensor may be placed on a bedside table next to a patient (e.g., next to the patient asthey are sleeping or prior / after sleeping) and may be configured to detect one or more cardiac values in connection with the embodiments described herein. Such determined cardiac values (e.g., heart rate) may then be used in connection with, for example, the illustrative examples discussed in Figures 11A-1 IB (and others).

[0243] In some embodiments, heart rate system 7001 may be suitable for unobtrusively monitoring or obtaining cardiac-respiratory attributes of a patient undergoing respiratory pressure therapy.

[0244] Heart rate system 7001 also may include one or more hardware processors configured to perform operations that are based on programmed instructions.Examples of such operations are discussed in connection with Figures 9A and 9B.

[0245] Heart rate system 7001 may include non-transitory computer readable memory that is configured to store instructions to perform such operations and / or to store sensor data (whether further processed or not) acquired based on the IMU 7006. In certain example embodiments, the one or more hardware processors may include a hardware processor that is: part of the IMU 7006, included in the RPT device 7002, or provided elsewhere (e.g., computing device 7030 - such as a mobile device, or as part of a cloud-based computing system or the like). For example, in an example, a first processor is included with IMU 7006, a second processor is included with RPT device 7002, and a third processor is provided in a mobile device that communicates with the RPT device 7002 (e.g., via Bluetooth, Wi-Fi, cellular technology, or the like).Multiple processors (including other processors) may cooperatively operate to generate, for example, the heartbeat / heart rate discussed in connection with Figures 9A and 9B, and then output data for viewing as shown in Figure 11 A.

[0246] In certain examples, an example IMU may provide data communication in the form of, for example, I2C. Such a protocol may be infeasible for communicating data along the length of the tube 7004. Accordingly, additional processing functionality may be included in a circuit board that also includes the IMU 7006.This may include an additional hardware processor or circuit to process or transform the signal from the IMU 7006 into a form for communication along the length of the tube (e.g., to an RPT device or a mobile device). For example, a circuit may take the data from the IMU 7006 in I2C and then generate messages that can be communicated using, for example RS-485 or the like.

[0247] In some examples, the data output from the IMU 7006 may be sent to another computing device for further processing. Alternatively, or additionally, insome examples, additional filtering and / or processing may be performed on the data output from the IMU 7006 before transmission (e.g., to the RPT device 7002 or computing device 7030). For example, the IMU may be located on a circuit board that also includes another processor that may process the IMU data. The process may perform, for example, a process for determining a heart rate (e.g., as discussed in Figures 9A or 9B) and the resulting heart rate determination may be communicated to another computing device. Such a transmission may be sent once every 10 seconds, 20 seconds, 30 seconds, 1 minute or other time frame in order to provide, for example, a stream of heartbeat messages. The messages may indicate a “current” heartbeat (e.g., over the past 1 minute, or other time period). In some examples, the provided heartbeat data may allow for “real” time monitoring (and taking subsequent action) of the person’s heartbeat. In certain example embodiments, the processing may be event driven such that each time a new beat is detected (e.g., each new peak in the signal that is classified as a heartbeat) may cause a message to be sent from the hardware resources in the tube 7004. Such functionality may be combined with, for example, communicating a running heartbeat metric.

[0248] As noted herein, in some examples, BCG techniques may be used for measuring a patient’s cardiac parameters such as heart rate (HR). BCG is a technique for measuring small movements (e.g., recoil) that are caused by blood being pumped around the body. Cardiac parameters can include, for example, the heart rate (e.g., bpm) and heart rate variability (HRV) and other.5.9.1 Sensor Placement

[0249] Figures 8A and 8B are cross-sectional function block diagrams that illustrate how an IMU may be provided with a tube in accordance with various forms for the present technology.

[0250] Tubes 8000 and 8050 are examples of air conduit 4170. Tubes 8000 and 8050 may be configured to connect to an outlet port of an RPT device on a first (e.g., distal) end (e.g., 8010). Tubes 8000 and 8050 may be configured to connect to a patient interface on a second (e.g., proximal) end (e.g., 8012). IMUs 8004 and 8054 are examples of IMU 7006. Tubes 8000 and / or 8050 may include multiple removable attachable sections. For example, the tubes may include an adapter at the proximal end that allows for coupling to different types of patient interfaces or the like. The IMU may be located in the adapter of the tube.

[0251] Referring now more specifically to Figure 8A, IMU 8004 is directly mechanically coupled to the tube 8000. In some examples this may be accomplished by inserting / disposing the IMU within, for example, the cuff 8002 that is configured to facilitate connection to a patient interface. IMU 8004 may be structurally coupled to the tube 8000 by, for example, overmolding the cuff 8002 such that the IMU is embedded therein. The IMU 8004 may be coupled to power and / or data wires that are provided within tube 8000. It will be appreciated that other positional locations for the IMU may be provided in accordance with example embodiments.

[0252] Referring to Figure 8B, IMU 8054 may be structurally coupled to tube via a combination of a spring 8058 and a damper 8056. The IMU 8054 may be otherwise unconnected to the structure of the tube 8050. Accordingly, for example, as the tube moves (e.g., as vibrations pass through the tube 8050), such movements may then be passed to the IMU 8054 via the damper 8056 and / or the spring 8058. The IMU may thus be suspended or otherwise structurally isolated from the tube 8050 and / or cuff 8052 thereof. The damper 8056 and / or the spring 8058 may be configured to mechanically filter out a range of frequencies. The frequencies that are filtered out may be those that are known not to be associated with the heart beats from a patient. The mechanical filtering may operate, in some examples, in combination with the signal processing techniques discussed in connection with figures 9A and / or 9B. Accordingly, some frequencies may be mechanically filtered without having to be filtered out electronically (e.g., via software or the like).

[0253] In certain example embodiments, the power and / or data wires that are respectively used to provide power and data communication for the IMU 8054 may be incorporated into the damper and / or spring.

[0254] In certain examples, position the IMU within the tube can allow for leveraging existing electrical options for powering the IMU (e.g., without having to resort on a battery or other power source). Further, existing wires of an existing tube design can be leveraged to provide data transmission capability (e.g., via RS 485). Thus, for example, one wire (or set of wires) can be used to provide power while another can provide data transmission capability.

[0255] It will be appreciated that placement of an IMU within (for example) the patient interface or on the body of the patient may generate a “better” signal of a sleeping patient in some instances. This may be because the amplitudes of the movements may be more pronounced (e.g., the sensor is closer to the body of thepatient). Accordingly, it may be easier (e.g., comparatively) to recognize a person’s heartbeat using data collected from an IMU located on a person or a mask they are wearing. In contrast, IMU placement in a tube (which can be connected to a patient interface) may include additional challenges. Accordingly, in some examples, additional processing may be performed on a generated signal in order to provide a heart rate determination. Such illustrative processing is discussed in connection with Figures 9A and 9B.5.9.2 Techniques For Determining Heart Rate

[0256] Figures 9A and 9B are flow charts of example processes that may be used for determining a heart rate. The techniques discussed in Figures 9A and 9B may be performed based on, for example, sensor data collected by IMU 7006.

[0257] Turning more specifically to Figure 9A, at 9000 sensor data is obtained. As discussed herein, the data obtained may be a fusion of one or more sensors (e.g., a gyro sensor and an acceleration sensor) that are included in an IMU. In certain examples, data from a gyro sensor was observed to be less noisy than that obtained from an acceleration sensor. Furthermore, it was observed that the data from the gyro sensor (e.g., in terms of amplitude and / or strength of signal) was larger than for the accelerometer. It will be appreciated, however, that as a person shifts in position (and the orientation of the IMU is adjusted) that such data may shift.

[0258] The sensor data that is obtained may be individually identified as the X, Y, and Z components of a signal output from a 3-axis IMU. The sensor data may be just from a gyro sensor, just from an acceleration sensor, or based on both acceleration sensor data and gyro sensor data (and may be in combination with a digital compass included in the IMU). An illustrative example of X, Y, and Z gyro sensor data (in Milli Degrees Per Second - mdps) is shown in Figure 10A. In some examples, the time frame for which the sensor data is acquired (for 9000) may be every minute, 30 second, 15 seconds, 10 seconds, 5 seconds, second, or the like. In some examples, the rate at which the IMU acquires sensor data may be provided at the same rate as sensor data 9000 (e.g., 50Hz or 100Hz, etc). In some examples, data may be collected by the IMU and then provided (e.g., as sensor data 9000) upon request. In other words, the example process discussed in Figure 9A may periodically request a batch of IMU sensor data for processing. Accordingly, for example, the techniques shown in Figure 9A may be performed, for example, every minute, every30 second, every 15 seconds, every 10 seconds, every 5 seconds, or the like. In some examples, data that is acquired at 9000 may be a rolling window of sensor data. For example, the data may be the prior 1 -minute window of data that is acquired (at 9000) every 5 seconds.

[0259] In some examples, the acquired sensor data may be in the time domain (e.g., 5 seconds of sensor data). In other examples, the data that is provided may be in the frequency domain (e.g., a Fast Fourier Transform may be applied to the time domain data).

[0260] At 9002, a Butterworth fdter is applied to the X, Y, and Z components of signal. In certain examples, that may include, applying a band pass filter with a lower cut off frequency of (e.g., between 0.5Hz and 1Hz, or between 0.6Hz and 0.8Hz, or about 0.67 Hz) and high cut off frequency (e.g., between 18 and 22 Hz, between 19 and 21Hz, or about 20Hz). Such processing may be applied to each of the components in the signal. In some examples, other types of filtering may be used (or may not be used and processing in 9002 may be skipped). An illustrative example of X, Y, and Z gyro sensor data subjected to such filtering (in mdps) is shown in Figure 10B.

[0261] At 9004, a high pass filter is applied with a cutoff of about 5Hz. It will be appreciated that the cutoff may vary according to certain examples. For example, the cut off may be between about 4 and 6Hz. In some examples, the cutoff may be - e.g., + / - 1, 2, 5, or 10%. It will be appreciated that body movement of the patient can result in large signals at a low frequency (e.g., at about 1Hz). Accordingly, selection of a frequency cutoff of about 5Hz can be used to remove low frequency noise while also preserve the higher frequency of the patient’s heart (e.g., which may be about 10Hz). It will also be appreciated that a frequency cut off may vary from patient to patient or circumstance to circumstance based on, for example, a known resting heart rate, or a level of physical movement of the patient. It will be appreciated that the filtering in 9004 is lower (at the high end) than at 9002. It will also be appreciated that two different filtering steps are performed on the component signals of the signal data (first at 9002, then at 9004). An illustrative example of X, Y, and Z gyro sensor data subjected to such filtering (in mdps) is shown in Figure 10C. Also shown in in Figure 10C is a source of “truth” from an ECG (the bottom signal).

[0262] In some examples, the same cutoff threshold may be used for the high pass filter for each of the components. In other examples, different cutoff thresholdsmay be used for different ones of the components. For example, X may have a cutoff of 4.9Hz, Y 5Hz, and Z 5.1Hz. In some examples, the cutoff threshold may be based on a determined position of the patient (e.g., as discussed elsewhere herein). For example, whether a patient is sitting upright, or sleeping on their side, etc.

[0263] At 9006, the components (X, Y, and Z) are used to calculate a resulting magnitude vector. The magnitude vector g may be calculated as: g = ■ x2+ y2+ z2. An illustrative example of the resulting magnitude vector signal based on the fdtered X, Y, and Z gyro sensor data is shown in Figure 10D. Note that filtering of the individual component signals (e.g., in 9004) is performed prior to the vector calculation. This type of approach can be technically advantageous as the noise that is removed from the signals as a result of filtering in 9004 is not increased. In other words, calculating the vector in 9006 may include squaring the values of the individual component signals. Had the noise not been removed, such a process may have increased the noise in the resulting signal.

[0264] At 9008, a low pass filter is applied to the calculated magnitude vector to smooth out the resulting signal calculated from 9006. In certain examples, the cut off frequency for the low pass filter may be about 1.2Hz. In some examples, the cut off frequency may be adjusted up or down to be, for example between about 1Hz and 1.5Hz. In some examples, the cutoff may be - e.g., + / - 1, 2, 5, or 10%. In some examples, a cutoff for the low pass filter may depend on the slope of the filter - e.g., higher order filters can have steeper slopes or sharper cutoffs. As an illustrative example of how the cut off may be adjusted, if a patient has a higher heart rate (e.g., 78bpm or about 1.3Hz), then a cut off of 1.2 Hz could lose the heart rate signal. Thus, determination of heart rate may vary between different patients (e.g., different patients may have different cutoffs) or the circumstances of the patient. For example, determination of a resting heart rate as discussed herein may use a less aggressive filter cutoff (e.g., to ensure a baseline resting heart rate is obtained) than during sleep.

[0265] Note that in some examples, some filtering is performed prior to generation of the magnitude vector (e.g., 9002 and 9004) and some filtering is performed after (e.g., 9006).

[0266] An illustrative example of the signal subjected to the filtering performed at 9006 is shown in Figure 10E. Also shown in the graph of Figure 10E is the signal prior to filtering, and the ground truth signal (an ECG signal).

[0267] At 9010, a time window over the frequency data is determined. In some examples, this may be a 1-minute window (e.g., to calculate a number of beats per minute) or a 30-second window or other period. In other examples differing windowing schemes may be used. In certain example embodiments, the 1-minute window may be a rolling window with, for example, 5- or 10-seconds intervals. The use of the windowing of the data may allow for defining the scope of data on which peak detection is to be performed (at 9012).

[0268] At 9012, the number of peaks in a signal is calculated. Different types of techniques may be used to determine peaks of a signal within a given window. In certain examples, this may be performed using the scipy fmdpeaks() function. This function is provided as part of the open-source SciPy library, which is a collection of functions for math, science, and engineering.

[0269] In combination with the determining of the peaks (or as an alternative), an option for finding peaks within the processed signal is using peak detection process 9020. This process includes, at 9022, estimating a number of maximum turning points in the signal (e.g., by using the fmdpeaks() function for example). This may include identifying each turning point in the signal. This is illustratively shown in Figure 10F in which the turning points shown from the ground truth are shown in band 1050, and the identified turning points of the signal (from 9008) are shown in band 1052.

[0270] Then, at 9024, a mean of the signal is calculated. In some examples, the calculated mean (e.g., average) may be a mean of each peak (e.g., the amplitude of each turning point in the signal) that has been identified in the signal. Other averages or calculations based on the amplitude or other attribute of the signal may be used in accordance with certain examples.

[0271] At 9026, a threshold is applied to the signal. The threshold is based on the calculated mean and is used to remove lower or higher amplitude peaks (e.g., those less likely to reflect a heartbeat). In certain example embodiments, the threshold determined to be 20% from the calculated mean. Thus, for example, identified peaks with 120% (or more) from the mean amplitude and those identified peaks with 80% (or less) from the mean amplitude, may be removed as these may be less reflective of “real” heartbeats. Other values may be used (e.g., + / - 10%, 15%, 25%, 30%, etc). In other words, such techniques may be applied to remove artifacts from the signal thatare less likely to represent a heartbeat. In certain example embodiments, additional artefact rejection processing may be applied.

[0272] The illustration shown in Figure 10G shows an estimated heart rate of 56 compared to the ground truth signal of 53. The graph shown in Figure 10H shows how the estimation of heart rate may be compared to a ground truth signal over a timer period. Line 1090 is the ground truth and line 1092 is the generated heart rate value using the process shown in Figure 9A.

[0273] Other techniques for determining peaks within the signal (e.g., those that likely represent “real” heartbeats) may also be used in accordance with some examples. As an illustrative example, the Pan-Tompkins QRS detection algorithm (or a variation thereof) may be used to identify peaks within a signal that correspond to heartbeats. In certain example embodiments, the Fourier transform of the signal may be used to facilitate identification of heart beats within the signal.

[0274] With the number of peaks in the window calculated from 9012, then at 9014 the number of beats within the window are calculated. If the window is 1 minute long, then that would represent the heart rate (in beats per minute) of the person.

[0275] At 9016, the resulting calculated heart rate may be output. As discussed below the calculated heart rate may be used to in one or more downstream applications (e.g., as discussed elsewhere herein — such as in connection with, for example, Figures 11A-11B).

[0276] Turning to Figure 9B, another process for calculating heart rate from IMU sensor data is provided. The process shown in Figure 9B may use de-noising in the wavelet domain. In certain examples, a soft thresholding strategy may be adopted for this domain. A biorthogonal 5.5 wavelet can be used to obtain four sets of approximation coefficients and one set of detail coefficients at four scales. The detail coefficients and the approximation coefficients in the lowest scale may be discarded, and soft thresholding can be applied to the other three sets of coefficients. The threshold for each level may be calculated as a 2x of the standard deviation of the coefficients in this level. Then the root mean square (L2 norm) of the 3 -axis vector, is calculated and used to estimate heart rate.

[0277] In some examples, heart rate estimation from the denoised norm of the 3- axis vector can be divided into the following steps. First, Wavelet denoise the X, Y and Z components using the “bior5.5” (biorthogonal 5.5 wavelet). This may be doneby using a pywavelet (pywt) module in python. A thresholding strategy of 2*std of that level was used. In other words, thresholds = [np.std(c) * 2 for c in coeflfs],

[0278] Next, the L2 norm vector was then calculated from the denoised signals. And a signal envelope was extracted using a Hilbert transform.

[0279] A 4th-order band-pass Butterworth fdter may then be applied to keep the signal component with cutoff frequency of 0.67 Hz and 3.33 Hz, which corresponds to 40 to 200 beats per minute (BPM).

[0280] Referring now more specifically to Figure 9B, a flow chart of an example process is shown. At 9050, sensor data is obtained. As discussed herein, the data obtained may be a fusion of one or more sensors that are included in an IMU. The sensor data that is obtained may be the individual X, Y, and Z components of the signal output from an IMU.

[0281] At 9052, wavelet denoising is applied to the components. For example, a biorthogonal 5.5 wavelet was used to denoise the X, Y, and Z components with a thresholding strategy of 2 times the standard deviation level.

[0282] At 9054, a magnitude vector is calculated from the denoised X, Y, and Z signals.

[0283] At 9056, the magnitude vector is subject to a high pass filter. The high pass filter may include a cut off of about 3Hz.

[0284] At 9058, peaks are found within the signal. This may include using the scipy fmdpeaks function and / or using peak detection process 9020.

[0285] At 9060, a heart rate is calculated for a number of peaks within a given time frame (e.g., 1 minute). As with the Example from Figure 9A, the resulting heartbeat may be used in one or more downstream applications.

[0286] Other possible data processing techniques based on the IMU data may be used in connection with some example implementations.

[0287] In some examples, data from the IMU 7006 may be used to determine a sleep position (e.g., a sleep pose) of a sleeping person. For example, there may be multiple different sleep positions including, for example, supine, side sleeping (on either the left or right) and in either supported or provocative, or stomach sleeping. In some examples, data output from the IMU may be used to directly calculate a sleeping position. In some examples, data from the IMU may be used to calculate positional changes between different sleeping positions (which may then be used to infer which position a person is in).5.9.3 Heart Rate Applications

[0288] Figures 11A-1 IB are illustrative graphical user interfaces (GUI) that show different example implementations for how a heart rate may be displayed according to various forms of the present technology. The GUIs shown herein may be displayed on a display of the RPT device 7002 and / or may be displayed on a display coupled to computing device 7030. In some examples, an “app” may be used to display the data shown in these figures to a patient, another person, or a clinician.

[0289] Figure 11A shows three graphical user interfaces according to various forms of the present technology. GUIs 1100 and 1106 may be the same user interface with different resulting data included therein.

[0290] GUIs 1100 and 1106 include a graph (1102 / 1108) that may show a patient’s heart rate over a time period. The period may be a set time (e.g., 8 hours) or may be determined as the time period the person spent sleeping. In some examples, the determination of sleep stage (as discussed elsewhere herein) may be used to determine the length of sleep time.

[0291] In any event, the graphs may show the calculated heart rate data (not shown) and also show a curve (1105 and 1109) that is fitted to that data. As shown, curve 1105 is different from curve 1109. Each curve may act as a personalized sleeping heart rate curve and can be viewed as a signature for the sleeping person for a given night. By presenting a curve to a user, it can be used to provide feedback to the user on their overall sleep quality.

[0292] In some examples, the determined curve may be selected from one of multiple possible preset curves that “best” fits the underlying heart rate data. For example, a type 4 signature is provided in GUI 1100 while a type 2 is shown in GUI 1106. In other examples, a curve fitting algorithm may be used to generate a curve for the heart rate data.

[0293] GUIs 1100 and 1106 may also include the total sleep time for the user, the range of heartbeat rates through the night as the person was sleeping, when the person was determined to fall asleep, and when the person was determined to wake up.

[0294] Examine these (and / or other) factors can assist a person in understanding their sleep quality. For example, if, over the course of a night, a person starts with a higher heart rate (e.g., when they fall asleep at, for example, 11pm), which then dips to a lower point (e.g., as 2am for example), and then gradually rises before the personwakes up (e.g., at 7am). Such a signature may be classified as a “good” sleep or that the person slept well. This is illustrated in graphical user interface 1100. Other possible types of sleep may include working out too soon before sleeping which leads to a higher heart rate upon falling asleep (which falls through the night). When a person wakes up, they may be tired. If a person goes to bed with a low heart rate (e.g., the person is tired); then drop; and then rise. This may be classified as poor sleep.

[0295] Such sleep data may be presented to a patient, which can then be used to help a patient adjust one or more aspects in order to achieve an improved sleep.

[0296] Another GUI that may be generated and displayed may be GUI 1110. GUI 1110 includes a plurality of sleep factors that may be displayed to a user. These may be separated into positive factors (e.g., factors that tend to result in improved sleep quality) and negative factors (factors that tend to result in decrease sleep quality).

[0297] In some examples, these may be presented as a list of factors. In some examples, the factors may be classified based on one or more inputs to automatically identify / classify those factors that have contributed to a sleep. In some examples, users may be prompted to input (for example), the time at which they eat or worked out (e.g., factors that may provide decreased sleep quality if performed by a person too close to their sleep time). In some examples, such data may be automatically collected (e.g., from a smart watch that records workout information, etc). Such data may then be used to prompt users towards improved sleep routines (which may then result in improved sleep quality).

[0298] In some examples, a sleep system may be provided that operates on the heart rate determination techniques discussed and may acquire other signals to facilitate the identification of one or more conditions (e.g., sleep conditions)for a patient. As an example, a flow signal metric (e.g., as discussed in connection with the RPT device algorithms herein) may be acquired in order to determine (for example), if / when a person has fallen asleep. By combining the flow signal metric (e.g., as discussed in connection with the RPT device algorithms herein, such as the respiratory flow rate estimation) with a heart rate, in some examples, the sleep system can then assist in identification of sleep conditions like Bruxism, Restless Ueg Syndrome (RLS), insomnia, etc. Based on identification of such conditions, one ormore personalized / customized treatments can be presented to the user (e.g., meditation exercises, tips before bed, etc.) and / or insomnia solutions can be provided.

[0299] As another example, the heart rate of a patient may be determined while the patient is awake (or transitioning from awake to sleep / or from sleep to awake). The determined heart rate may then be compared to a threshold heart rate. The threshold may be based on a previously determined resting heart rate or may be otherwise set. Based on the comparison, one or more additional prompts may be presented to a user (e.g., via a graphical user interface) to suggest one or more techniques to adjust or control their heart rate. For example, if a patient’s heart rate is elevated prior to sleep, a prompt with a suggestion of paced breathing or a mindfulness exercise may be presented to the patient. This may allow the patient to gradually decrease their heart rate to a level that may improve overall sleep quality. In some examples, distinct types of prompts may be provided based on the determined heart rate. For example, a first prompt may be provided when a heart rate is determined at a first level and a second prompt may be provided when the heart rate is determined at a second level. In some examples, the types of prompts may be based on whether the patient is going to sleep or is waking up from sleep.

[0300] In Fig. 1 IB, an example graphical user interface 1120 is shown. In 1120, a resting heart rate 1122 is displayed. A resting heart rate can provide insight into a person’s overall health. This value may be presented to patient, clinicians, or other users as needed and can enable a better understanding of cardiovascular health, physical fitness, and / or recovery trends overtime. In some examples, the resting heart rate 1122 that is displayed is based on an average resting heart for a minute, an hour, a day, or other time period. In some examples, a heart rate may be determined as a patient is waking up after sleeping. For example, each morning the patient wakes up may include determining the patient’s resting heart rate (e.g., forthat day). This may be performed while the patient is still in bed (e.g., and with the patient interface engaged to the face of the patient).

[0301] Graph 1124 that is included in GUI 1120 may be a historical graph that allows for monitoring changes to a resting heart rate over a period of time (e.g., a week, a month, a year, etc.). This can allow users and / or healthcare providers to make more informed decisions to improve well-being and address potential health issues proactively. For example, a higher resting heart rate (e.g., in the short term) can be indicative of factors such as poor sleep and the like.

[0302] In some examples, a monitored resting heart rate may be combined with other signals. For example, the AHI of a user may be monitored as well and included into GUI 1120 (e.g., as part of graph 1124). This can allow patients (and clinicians or other users in certain example) to visualise how their sleep quality of life has improved (e.g., via the use of respiratory therapy).

[0303] Another example use of certain techniques described herein is shown in GUI 1130 that displays a calculation of a sleep score 1132. The calculated sleep score may be a function of any or all of 1) AHI, 2) heart rate 1134, 3) sleep position 1136, 4) sleep activity 1138, 5) usage of a mask (e.g., 6 hours), and / or other factors. A sleep score may provide users with insight into the link between continued respiratory therapy (e.g., PAP or CPAP) and obtaining improved sleep quality. In some examples, the sleep score may be plotted on an historical graph so as to show users their overtime change in sleep. In some examples, additional data, such as heart rate, AHI, and / or other factors may be included in such a graph.

[0304] In certain example embodiments, any or all of sleep position, sleep activity, and heart rate may be used to facilitate determination of a sleep stage of a sleeping person. In some examples, sleep stages may be one of: awake, REM, Core (or light), and Deep sleep. Additional or alternative stages may be used in accordance with some examples.

[0305] In some examples, the sleep stage of a sleeping person may be derived from analysis of a flow signal processed by an RPT device (e.g., RPT device 4000 - for example a respiratory flow rate estimation). Such a calculation may be augmented based on any or all of parameters associated with sleep position, sleep activity, and / or heart rate. In some examples, the addition of one or more of these further parameters may allow for obtaining a more precise determination of the sleep stage of a sleeping person. In some examples, the addition of one or more of these further parameters to a sleep stage calculation may allow for real-time calculation of the sleep stage of a person. In other words, some techniques for calculating sleep stage may not be able to operate in real time. Instead, a full night’s sleep may be needed in order to understand the different stages of a person’s sleep. In certain examples, the use of sleep position, sleep activity, and / or heart rate can allow for real-time (or quasi-real time) determination of sleep stage. For example, within 1 minute, within 30 seconds, within 10 or 15 seconds, etc.

[0306] By determining a sleep stage in real time, the determination may be acted upon to control respiratory therapy for the patient while they are sleeping (e.g., during respiratory therapy).

[0307] As an illustrative example, as the user drifts off to sleep, the RPT device may ramp the pressure (e.g., based on a patient switching from an awake state to a sleeping state. Further, as the patient wakes up, the pressure can be gently decreased. This can help facilitate smoother and / or more comfortable transition to wakefulness for the user (e.g., because the pressure setting at the flow generator is at a lower pressure setting). It will be appreciated, that decreasing the awake experience of therapy pressure for a user can assist in promoting a more natural and / or restful sleep experience for users of respiratory therapy.

[0308] As another illustrative example, the RPT system can be configured to decrease pressure during a deep sleep and increase the pressure during REM sleep. Such adjustments may be possible due to real time determination of a person’s sleep stage, which may be facilitated due to the techniques discussed herein of calculating sleep position, sleep activity, and / or heart rate. In some instances, this type of pressure adjustment based on sleep stage can preserve or lead to the benefits of a deep sleep while also delivering therapy for the patient (e.g., when it's most beneficial). By leveraging determination of sleep position, sleep activity, and / or heart rate for a real time sleep stage determination, the RPT system can provide improved comfort for patients, while also promoting deeper and more restorative sleep.

[0309] In some examples, the determination of sleep position, sleep activity, and / or heart rate (and / or how those attributes have changed) can be used to dynamically adjust flow settings, or other therapy settings (e.g., increase / decrease pressure, increase / decrease humidity, increase / decrease temperature, etc.) of an RPT device while the patient is sleeping.

[0310] In some examples, data from an IMU can be used to detect positional sleep apnea (POSA). By detecting the sleeping position of a patient, therapy can be adjusted. For example, therapy can be adjusted via dynamic pressure adjustment to thereby decrease AHI and deliver more comfortable therapy for a user who has more apneas in one (or more) sleeping positions than others. For example, when a patient is in the supine position and a POSA detected, the RPT device can dynamically increase pressure at a rapid pace (e.g., more rapidly than a traditional CPAP ramp adjustment). Such a quick / targeted adjustment of the pressure can lead to a lowerAHI for the patient — and thus provide more effective treatment of sleep apnea and a better night’s sleep.

[0311] In contrast, when a patient is side sleeping, the RPT device can dynamically adjust the pressure to be decreased (e.g., to be quickly decreased pressure). The pressure may be, for example, decreased to a low threshold level (e.g., a minimal level) that is sufficient to keep the airway of the patient open. This type of therapy adjustment throughout the night can be more comfortable for a patient because a lower level of pressure is delivered for a greater portion of the night.

[0312] In certain examples, the determination of heart rate (e.g., as shown in Figures 11A and 1 IB), can be used to assist in acclimatization to respiratory therapy. More specifically, heart rate can be used to determine, for example, a comfort level of a patient with PAP therapy. If a patient’s heart rate is elevated, then it may indicate that they are not comfortable with their current respiratory therapy. Such information may be communicated to a clinician; who may then suggest one or more adjustments to therapy (e.g., with a goal of improving patient comfort).

[0313] In contrast, when a patient is side sleeping, the RPT device can dynamically adjust the pressure to be decreased (e.g., to be quickly decreased pressure). The pressure may be, for example, decreased to a low threshold level (e.g., a minimal level) that is sufficient to keep the airway of the patient open. This type of therapy adjustment throughout the night can be more comfortable for a patient because a lower level of pressure is delivered for a greater portion of the night.

[0314] In some examples, the calculation of heart rate data (e.g., as discussed herein), sleep pose data, and flow data (e.g., as discussed in connection with the RPT device algorithms herein) may be combined to determine, for example, cardiopulmonary coupling for the sleeping person.

[0315] As discussed herein, the determination of heart rate, particularly in sleeping patients undergoing respiratory therapy, can present challenges.Conventional techniques — e.g., manual pulse measurement, electrocardiography (ECG), pulse oximetry, and the like — can often require physical contact with the patient or the use intrusive devices (e.g., chest straps, finger clips, electrodes, etc.). Such techniques can be uncomfortable, disrupt sleep, and / or may be impractical for continuous or long-term monitoring — especially in a home setting. PSG, while accurate in some situations for monitoring cardio-pulmonary parameters, may be a more expensive, labor-intensive, and / or unsuitable for routine or home-based use.Such issues can hinder the ability to (e.g., unobtrusively) and monitor (e.g., accurately) heart rate during sleep. The determination of heart rate can play a role in assessing sleep quality, detecting sleep-related disorders, and / or optimizing respiratory therapy.

[0316] The techniques discussed herein operate to determine heart rate using an inertial measurement unit (IMU) integrated into a respiratory therapy system. The described technique can leverage the IMU's ability to detect micro-movements associated with ballistocardiography (BCG) to unobtrusively monitor cardiac activity. The IMU can be positioned within the air circuit or patient interface to capture multiaxis motion data (e.g., X, Y, and Z components) generated by the patient’s physiological movements during sleep. The captured data can then be processed using the techniques (e.g., algorithms) discussed herein. These may include high-pass and low-pass filtering, magnitude vector calculations, and / or peak detection techniques. These may be used to determine heart rate without requiring additional wearable devices or invasive sensors.

[0317] The techniques discussed herein facilitate seamless integration with existing respiratory therapy systems, such as Continuous Positive Airway Pressure (CPAP) devices, while maintaining patient comfort and therapy effectiveness. Unobtrusive monitoring of heart rate in real-time supports improved sleep analysis, including the generation of sleep metrics, sleep stage identification, and personalized therapy adjustments. Additionally, the techniques may include those that enables heart rate calculation with increased reliability — even under conditions of noise or patient movement. The described techniques thus can offer a cost-efficient, user-friendly, and / or adaptable solution for continuous heart rate monitoring in home (and clinical) settings.5.10 GUOSSARY

[0318] For the purposes of the present technology disclosure, in certain forms of the present technology, one or more of the following definitions may apply. In other forms of the present technology, alternative definitions may apply.5.10.1 General

[0319] Air. In certain forms of the present technology, air may be taken to mean atmospheric air, and in other forms of the present technology air may be taken to mean some other combination of breathable gases, e.g. oxygen enriched air.

[0320] Ambient'. In certain forms of the present technology, the term ambient will be taken to mean (i) external of the treatment system or patient, and (ii) immediately surrounding the treatment system or patient.

[0321] For example, ambient humidity with respect to a humidifier may be the humidity of air immediately surrounding the humidifier, e.g. the humidity in the room where a patient is sleeping. Such ambient humidity may be different to the humidity outside the room where a patient is sleeping.

[0322] In another example, ambient pressure may be the pressure immediately surrounding or external to the body.

[0323] In certain forms, ambient (e.g., acoustic) noise may be considered to be the background noise level in the room where a patient is located, other than for example, noise generated by an RPT device or emanating from a mask or patient interface. Ambient noise may be generated by sources outside the room.

[0324] Automatic Positive Airway Pressure (APAP) therapy. CPAP therapy in which the treatment pressure is automatically adjustable, e.g. from breath to breath, between minimum and maximum limits, depending on the presence or absence of indications of SDB events.

[0325] Continuous Positive Airway Pressure (CPAP) therapy. Respiratory pressure therapy in which the treatment pressure is approximately constant through a respiratory cycle of a patient. In some forms, the pressure at the entrance to the airways will be slightly higher during exhalation, and slightly lower during inhalation. In some forms, the pressure will vary between different respiratory cycles of the patient, for example, being increased in response to detection of indications of partial upper airway obstruction, and decreased in the absence of indications of partial upper airway obstruction.

[0326] Flow rate'. The volume (or mass) of air delivered per unit time. Flow rate may refer to an instantaneous quantity. In some cases, a reference to flow rate will be a reference to a scalar quantity, namely a quantity having magnitude only. In other cases, a reference to flow rate will be a reference to a vector quantity, namely aquantity having both magnitude and direction. Flow rate may be given the symbol Q. ‘Flow rate’ is sometimes shortened to simply ‘flow’ or ‘airflow’.

[0327] In the example of patient respiration, a flow rate may be nominally positive for the inspiratory portion of a breathing cycle of a patient, and hence negative for the expiratory portion of the breathing cycle of a patient. Device flow rate, Qd. is the flow rate of air leaving the RPT device. Total flow rate, Qt, is the flow rate of air and any supplementary gas reaching the patient interface via the air circuit. Vent flow rate, Qy, is the flow rate of air leaving a vent to allow washout of exhaled gases. Leak flow rate, QI, is the flow rate of leak from a patient interface system or elsewhere. Respiratory flow rate, Qr, is the flow rate of air that is received into the patient's respiratory system.

[0328] Flow therapy. Respiratory therapy comprising the delivery of a flow of air to an entrance to the airways at a controlled flow rate referred to as the treatment flow rate that is typically positive throughout the patient’s breathing cycle.

[0329] Humidifier. The word humidifier will be taken to mean a humidifying apparatus constructed and arranged, or configured with a physical structure to be capable of providing a therapeutically beneficial amount of water (FLO) vapour to a flow of air to ameliorate a medical respiratory condition of a patient.

[0330] Leak. The word leak will be taken to be an unintended flow of air. In one example, leak may occur as the result of an incomplete seal between a mask and a patient's face. In another example leak may occur in a swivel elbow to the ambient.

[0331] Noise, conducted (acoustic)'. Conducted noise in the present document refers to noise which is carried to the patient by the pneumatic path, such as the air circuit and the patient interface as well as the air therein. In one form, conducted noise may be quantified by measuring sound pressure levels at the end of an air circuit.

[0332] Noise, radiated (acoustic)'. Radiated noise in the present document refers to noise which is carried to the patient by the ambient air. In one form, radiated noise may be quantified by measuring sound power / pressure levels of the object in question according to ISO 3744.

[0333] Noise, vent (acoustic)'. Vent noise in the present document refers to noise which is generated by the flow of air through any vents such as vent holes of the patient interface.

[0334] Oxygen enriched air. Air with a concentration of oxygen greater than that of atmospheric air (21%), for example at least about 50% oxygen, at least about 60%oxygen, at least about 70% oxygen, at least about 80% oxygen, at least about 90% oxygen, at least about 95% oxygen, at least about 98% oxygen, or at least about 99% oxygen. “Oxygen enriched air” is sometimes shortened to “oxygen”.

[0335] Medical Oxygen'. Medical oxygen is defined as oxygen enriched air with an oxygen concentration of 80% or greater.

[0336] Patient. A person, whether or not they are suffering from a respiratory condition.

[0337] Pressure: Force per unit area. Pressure may be expressed in a range of units, including cmfhO. g-f / cm2and hectopascal. 1 cmHjO is equal to 1 g-f / cm2and is approximately 0.98 hectopascal (1 hectopascal = 100 Pa = 100 N / m2= 1 millibar ~ 0.001 atm). In this specification, unless otherwise stated, pressure is given in units of cmHiO.

[0338] The pressure in the patient interface is given the symbol Pm, while the treatment pressure, which represents a target value to be achieved by the interface pressure Pm at the current instant of time, is given the symbol Pt.

[0339] Respiratory Pressure Therapy. The application of a supply of air to an entrance to the airways at a treatment pressure that is typically positive with respect to atmosphere.

[0340] Ventilator. A mechanical device that provides pressure support to a patient to perform some or all of the work of breathing.5.11 OTHER REMARKS

[0341] 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 Patent Office patent files or records, but otherwise reserves all copyright rights whatsoever.

[0342] Unless the context clearly dictates otherwise and where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit, between the upper and lower limit of that range, and any other stated or intervening value in that stated range is encompassed within the technology. The upper and lower limits of these intervening ranges, which may be independently included in the intervening ranges, are also encompassed within the technology, subject to any specifically excluded limit in the stated range. Where the stated rangeincludes one or both of the limits, ranges excluding either or both of those included limits are also included in the technology.

[0343] Furthermore, where a value or values are stated herein as being implemented as part of the technology, it is understood that such values may be approximated, unless otherwise stated, and such values may be utilized to any suitable significant digit to the extent that a practical technical implementation may permit or require it.

[0344] Furthermore, “approximately”, “substantially”, “about”, or any similar term used herein means + / - 5-10% of the recited value.

[0345] Unless defined otherwise, 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 the exemplary methods and materials are described herein.

[0346] When a particular material is identified as being used to construct a component, obvious alternative materials with similar properties may be used as a substitute. Furthermore, unless specified to the contrary, any and all components herein described are understood to be capable of being manufactured and, as such, may be manufactured together or separately.

[0347] It must be noted that as used herein and in the appended claims, the singular forms "a", "an", and "the" include their plural equivalents, unless the context clearly dictates otherwise.

[0348] All publications mentioned herein are incorporated herein by reference in their entirety to disclose and describe the methods and / or materials which are the subject of those publications. The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present technology is not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided may be different from the actual publication dates, which may need to be independently confirmed.

[0349] The terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating thatthe referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced.

[0350] The subject headings used in the detailed description are included only for the ease of reference of the reader and should not be used to limit the subject matter found throughout the disclosure or the claims. The subject headings should not be used in construing the scope of the claims or the claim limitations.

[0351] Although the technology herein has been described with reference to particular examples, it is to be understood that these examples are merely illustrative of the principles and applications of the technology. In some instances, the terminology and symbols may imply specific details that are not required to practice the technology. For example, although the terms "first" and "second" may be used, unless otherwise specified, they are not intended to indicate any order but may be utilised to distinguish between distinct elements. Furthermore, although process steps in the methodologies may be described or illustrated in an order, such an ordering is not required. Those skilled in the art will recognize that such ordering may be modified and / or aspects thereof may be conducted concurrently or even synchronously.

[0352] It is therefore to be understood that numerous modifications may be made to the illustrative examples and that other arrangements may be devised without departing from the spirit and scope of the technology.

Claims

6 CLAIMS1. A method of determining a heart rate of a patient that is sleeping while wearing a patient interface while being supplied with Positive Airway Pressure from a respiratory therapy device that includes a flow generator, the method comprising: obtaining, from an inertial measurement unit (IMU) that is configured to output data based on movement of the patient, sensor data, wherein the sensor data includes X, Y, and Z components; performing high pass filtering that is based on each of the X, Y, and Z components of sensor data at a first cutoff frequency; calculating a magnitude vector signal that is based a combination of each of the X, Y, and Z components of the sensor data to which the high pass filtering has been performed; performing low pass filtering that is based on magnitude vector signal at a second cutoff frequency; classifying, within a time window, peaks within a signal that is based on the filtered magnitude vector signal; and calculating a heart rate for the patient that is based on a number of peaks identified within the signal.

2. The method of any of the above claims, wherein the first cutoff frequency is about 5Hz.

3. The method of any of the above claims, wherein the second cutoff frequency is about 1.2Hz.

4. The method of any of the above claims, further comprising: performing a Butterworth band pass filter based on each of the X, Y, and Z components of the sensor data, wherein the high pass filtering is performed subsequent to the Butterworth band pass filter for the X, Y, and Z components of the sensor data.

5. The method of claim 4, wherein a low cutoff frequency for the Butterworth band pass filter is less than 1Hz and the high cut off frequency is about 20 Hz.

6. The method of any of the above claims, wherein the sensor data is data from a gyro sensor.

7. The method of any of the above claims, wherein the sensor data does not include acceleration sensor data.

8. The method of any of the above claims, further comprising: calculating, based on the classified peaks, a baseline peak value; and removing those classified peaks that are outside of a threshold from the baseline peak value, wherein the heart rate is further based on a number of peaks after removal of peaks that are outside of the threshold.

9. The method of claim 8, wherein the baseline peak value is calculated as a mean of the classified peaks, wherein the threshold is about 20% from the baseline peak value.

10. The method of any of the above claims, wherein an air conduit is configured to removably fluidly couple to the patient interface to the flow generator, wherein the IMU is disposed in a portion of the air conduit.

11. The method of any of the above claims, further comprising: generating a graphical user interface that is based on the calculated heart rate.

12. The method of any of the above claims, wherein eh graphical user interface includes a graph of a calculated heart rate over a sleeping period for the patient.

13. The method of any of the above claims, further comprising: overlaying, on the graph, one of a plurality of sleep flow lines that reflect a quality of the patient sleep.

14. The method of any of the above claims, further comprising: selecting, from among the plurality of sleep flow lines, a sleep flow line that is determined to fit a signal of the heart rate of the patient, wherein the signal of the heart rate of the patient is based on repeated calculation of the heart rate for the patient.

15. The method of any of the above claims, further comprising: determining which sleeping position, out of multiple possible sleeping positions, in which the patient is sleeping.

16. The method of any of the above claims, further comprising: determining a sleep stage of the patient based on the calculated heart rate.

17. The method of claim 16, further comprising: analysing a flow signal of the patient while sleeping and during therapy, wherein the determination of sleep stage is further based on the analysis of the flow signal.

18. The method of claim 16, wherein the sleep stage is determined in real-time while the patient is sleeping.

19. The method of claim 16, further comprising: automatically adjusting one or more operating parameters for how respiratory therapy is delivered to the patient while sleeping based on the calculated heart rate or the determined sleep stage.

20. The method of claim 19, wherein the one or more operating parameters include at least one of: 1) a ramp time; 2) a ramp pressure; and / or 3) a pressure supplied by the flow generator.

21. The method of claim 16, further comprising: automatically adjusting one or more operating parameters for how respiratory therapy is delivered to the patient while sleeping based on: 1) the calculated heart rate or the determined sleep stage; and 2) the sleeping position of the patient.

22. A non-transitory computer readable storage medium storing computer executable instructions for determining a heart rate of a patient that is sleeping while wearing a patient interface while being supplied with Positive Airway Pressure from a respiratory therapy device that includes a flow generator, the stored instructions configured to cause at least one hardware processor to perform operations comprising: the method of any one of claims 1 to 21.

23. A heart rate system comprising: a memory coupled to at least one hardware processor that is configured to perform operations comprising: the method of any one of claims 1 to 21.

24. A respiratory therapy (“RPT”) system comprising: a flow generator configured to provide a positive pressure flow of gas to an airway of a patient; a patient interface configured to be worn by the patient; at least one hardware processor configured to perform operations comprising: the method of any one of claims 1 to 21.

25. An air delivery conduit configured to fluidly couple a patient interface to a respiratory therapy device of a positive airway pressure system, the air delivery conduit comprising: a tubular body configured to transport pressurized treatment air between a proximal end of the tubular body and a distal end of the tubular body, the proximal end being configured to fluidly couple to a patient interface, and the distal end being configured to fluidly couple to a respiratory therapy device; and an inertial measurement unit (IMU) supported at the proximal end, at least one damper structurally connecting the IMU to the tubular body at the proximal end; and at least one spring structurally connecting the IMU to the tubular body at the proximal end.

26. The air delivery conduit of claim 25, wherein the IMU is structurally isolated from the tubular body except via the at least one damper and the at least one spring.

27. The air delivery conduit of any one of claims 25-26, wherein the proximal end includes a cuff portion, and the IMU is provided within the cuff portion28. The air delivery conduit of any one of claims 25-27, further comprising: a plurality of wires, wherein at least one of the plurality of wires is electrically connected to the IMU.

29. A respiratory therapy (“RPT”) system comprising: a flow generator configured to provide a positive pressure flow of gas to an airway of a patient; a patient interface configured to be worn by the patient; and the air delivery conduit of any one of claims 25-28.

30. The RPT system of claim 29, further comprising at least one hardware processor configured to perform operations comprising: the method of any one of claims 1 to 21.

31. A method of determining a heart rate of a patient that is sleeping while wearing a patient interface while being supplied with Positive Airway Pressure from a respiratory therapy device, the method comprising: obtaining, from an inertial measurement unit (IMU) that is configured to output data based on movement of the patient, signal data that includes separate X, Y, and Z components; performing high pass filtering on each of X, Y, and Z components of sensor data at a first cutoff frequency; performing low pass filtering on a combined magnitude vector signal at a second cutoff frequency; based on the performed high pass filtering and the performed low pass filtering, classifying, within a time window, peaks within a filtered signal; andcalculating a heart rate for the patient that is based on a number of peaks identified within the signal.

32. The method of claim 31, further comprising: any one of method claims 2-21.

33. A non-transitory computer readable storage medium storing computer executable instructions for determining a heart rate of a patient that is sleeping while wearing a patient interface while being supplied with Positive Airway Pressure from a respiratory therapy device that includes a flow generator, the stored instructions configured to cause at least one hardware processor to perform operations comprising: the method of any one of claims 31 to 32.

34. A heart rate system comprising: a memory coupled to at least one hardware processor that is configured to perform operations comprising: the method of any one of claims 31 to 32.

35. A respiratory therapy (“RPT”) system comprising: a flow generator configured to provide a positive pressure flow of gas to an airway of a patient; a patient interface configured to be worn by the patient; at least one hardware processor configured to perform operations comprising: the method of any one of claims 31 to 32.

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